DESC:
FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]

“A WATER ABSORBENT POLYMER AND A PROCESS OF PREPARATION THEREOF”

Hindustan Gum & Chemicals Ltd., an Indian Company at: Birla Colony, Bhiwani 127021, Haryana, India

THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

Field of the Invention:
The present invention provides a super water absorbent polymer product which includes a synthetic polymeric material and a poly glycosyl polymer chain grafted together. The super water absorbent polymer can be mixed with soil and increases the water retention capacity of the soil.

Background of the Invention:
Super water absorbent is an extremely hydrophilic polymer that is crosslinked into a three- dimensional network and has a unique ability to absorb at least a few hundred times of water as compared to its original dry weight. Super water absorbents based on acrylic acid or acrylate polymers have good absorption, retention and permeability properties.

However, super water absorbents, exclusively based on acrylic acid or acrylate polymers, have an inadequate level of biodegradability. Especially, when super water absorbents are used for agricultural purposes, use of super water absorbents exclusively based on acrylic acid or acrylate polymers is disadvantageous.

In some cases, super water absorbents have been made by admixing acrylic acid or acrylatepolymers with natural polymers. The admixtre of acrylic acid or acrylate polymers and natural polymers does not however increase biodegradability of the acrylic acid polymers.

In some cases, natural polymers have been co-polymerized with the acrylic acid or acrylate polymers to form the super water absorbents. However, a lot of difficulties have been faced while adopting this route. By way of example, a weight percentage of the natural polymers as determined on the basis of a total weight percentage of the super water absorbent is limited. Typically, the weight percentage of the natural polymers as determined on the basis of the total weight percentage of the super water absorbent is about 5 to 15 wt.%. By way of another example, attempts to increase the weight percentage of the natural polymers beyond about 15 wt.% results in a mass and more particularly a gel material which is difficult to process.

Thus, there exists a need to provide a super water absorbent polymer product which includes a synthetic polymeric material and more than about 15 wt% of a natural polymer and which is easy to process into a final product. Additionally, there exists a need to load a substantial quantity of a plant nutrient on to the super water absorbent. The loading of the plant nutrient on to the super water absorbent should be in such a manner that the plant nutrient gets released over a period of time to soil (upon mixing the super water absorbent with the soil).

Summary of the invention:
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key or essential features.

Accordingly, the present invention provides a super water absorbent polymer comprising: at least one acrylic acid or acrylate polymer chain; and at least one polyglucosyl polymer chain linked to the at least one acrylic acid or acrylate polymer chain.

In an embodiment of the invention, the polyglucosyl polymer chain is present in an amount in the range of about 18 to about 90% by weight of the super water absorbent polymer. In another embodiment of the invention, the polyglucosyl polymer chain comprises a modified starch. In yet another embodiment of the invention, an aqueous solution containing 50% w/v of the polyglucosyl polymer chain has viscosity in the range of 5000-50000 cps at a room temperature.

The invention furthermore provides a process for preparing the super water absorbent polymer, said process comprising: mixing one acrylic acid or acrylate monomer, a polyglucosyl polymer and a cross-linking agent under a polymerizing condition to obtain the super water absorbent polymer

In an embodiment of the invention, the polyglucosyl polymer chain is present in an amount in the range of about 18 to about 90% by weight of the super water absorbent polymer. In another embodiment of the invention, the polyglucosyl polymer chain comprises a modified starch. In yet another embodiment of the invention, an aqueous solution containing 50% w/v of the polyglucosyl polymer chain has viscosity in the range of 5000-50000 cps at a room temperature.

The super water absorbent polymer product of the present invention addresses the limitations of traditional acrylic acid or acrylate-based super absorbents by incorporating natural polymers and especially at least one polyglucosyl polymer chain for increased biodegradability. The present invention additionally offers benefits such as enhanced water absorption, long term moisture retention, nutrient delivery, ease of processing, and sustainability, making it a promising solution for efficient and eco-friendly agricultural practices.

To further clarify advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings.

Detailed description of the Figures:
In order that the invention may be readily understood and put into practical effect, reference will now be made to exemplary embodiments as illustrated with reference to the accompanying drawings. The figures together with a detailed description below, are incorporated in and form part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages, in accordance with the present invention where:
Figure 1 illustrates FTIR spectra of super absorbent polymer, in accordance with an embodiment of the invention; and
Figure 2 illustrates TGA Spectra of super absorbent polymer in accordance with an embodiment of the invention.

Detailed Description of the invention:
For the purpose of promoting an understanding of the principles of the invention, specific language will be used for describing the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications being contemplated as would normally occur to one skilled in the art to which the invention relates. It will be understood by those skilled in the art that the foregoing general description and the following detailed description are explanatory of the invention and are not intended to be restrictive thereof. Prior to explaining the invention, some of the terms which have been used in the specification are defined in the following paragraphs.

A glycosyl group is a univalent free radical or substituent structure obtained by removing the hemiacetal hydroxyl group from the cyclic form of a monosaccharide and, by extension, of a lower oligosaccharide. The glycosyl group has the chemical structure - I as shown below :
… I

Two or more (preferably more) glycosyl groups can be linked to one another to form a poly glycosyl polymer chain.

In a preferred aspect of the invention, the poly glycosyl polymer chain substantially resembles the structure of at least one of an Amylose (having the chemical structure II), an Amylopectin (having the chemical structure III), pullulan (having well known chemical structure, which is not shown), glycogen (having well known chemical structure, which is not shown), dextran (having well known chemical structure, which is not shown), chrysolaminarin (having well known chemical structure, which is not shown), curdlan (having well known chemical structure, which is not shown), laminarin (having well known chemical structure, which is not shown), lentinan (having well known chemical structure, which is not shown), lichenin (having well known chemical structure, which is not shown), pleuran (having well known chemical structure, which is not shown), and zymosan (having well known chemical structure, which is not shown).

… II

…III

In a preferred embodiment of the invention, since predominantly comprises amylose and amylopectin, both of which contain glycosyl polymer chains, starch can be used as the source of the glycosyl polymer chains. The starch can be obtained from natural resources as well as can be from artificial resources (for example, can be synthesized in the laboratory). Starch can be categorized into native starches and modified starches.

Modified starches are used in applications requiring special properties not attainable by native starches. Chemical modifications of native starches are often performed, in an aqueous suspension under controlled conditions of pH, time and temperature, unless otherwise indicated in the description of the respective annex. After sufficient reaction time, the modified starch is recovered by filtration or centrifugation, washed with water, dried and packaged.

The relevant modification reactions can be, separately or in combination, fragmentations (hydrolysis, oxidation, enzymatic), bleaching, oxidation, esterification, etherification or phosphorylation of one or more of the hydroxyl groups of the a-D-glucopyranosyl units or crosslinking using poly functional agents.

The term dextrinised starch or dextrin roasted starch comprises by way of non-limiting example, starches that are obtained by dry heating or roasting of native starch with hydrochloric acid or ortho-phosphoric acid in heated and/or agitated vessels. Dextrinised starch or dextrin roasted starch include starches identified by International Numbering System (INS) number 1400.

The term acid treated starch comprises by way of non-limiting example, starches that are obtained by treating a slurry or a suspension of native food starch with dilute hydrochloric acid, ortho-phosphoric acid, or sulphuric acid and include starches identified by INS number 1401.

The term alkali treated starch comprises by way of non-limiting example, starches that are obtained by treating a suspended solution of native food starches with sodium hydroxide or potassium hydroxide and include starches identified by INS number 1402.

The term bleached starch comprises by way of non-limiting example, starches that are obtained by treating a suspended solution of native food starches with Peracetic acid and/or hydrogen peroxide, or sodium hypochlorite, sodium chlorite, sulfur dioxide, alternative permitted forms of sulphites, potassium permanganate, or ammonium persulfate and include starches identified by INS number 1403.

The terms oxidized starch comprises by way of non-limiting example, starches that are obtained by treatment of food starch with sodium hypochlorite and include starches that are identified by INS number 1404.

The term enzymatically modified starch comprises by way of non-limiting example, starches that are obtained by treating a suspension of native food starch with one or more food-grade amyolytic-enzymes (e.g., a-amylase (E.C. 3.2.1.1), ß-amylase (3.2.1.2), glucoamylase (3.2.1.3), isoamylase (3.2.1.68), pullulanase (E.C. 3.2.1.41)) and include starches that are identified by INS number 1405.

The term mono-starch phosphate comprises by way of non-limiting example, starches that are obtained by esterification/crosslinking of unmodified food starch with ortho-phosphoric acid, or sodium or potassium orthophosphate, or sodium tripolyphosphate and include starches that are identified by INS number 1410.

The term di-starch phosphate comprises by way of non-limiting example, starches that are obtained by crosslinking of unmodified food starch with sodium trimetaphosphate or phosphorus oxychloride and include starches that are identified by INS number 1412.

The term phosphated di-starch phosphate comprises by way of non-limiting example, starches that are obtained by esterification/crosslinking of unmodified food starch with sodium trimetaphosphate or phosphorus oxychloride combined with esterification with orthophosphoric acid, or sodium or potassium orthophosphate, or sodium tripolyphosphate and include starches that are identified by INS number 1413.

The term acetylated distarch phosphate comprises by way of non-limiting example, starches that are obtained by esterification/crosslinking of unmodified food starch with sodium trimetaphosphate or phosphorus oxychloride combined with esterification with acetic anhydride or vinyl acetate and include starches that are identified by INS number 1414.

The term starch acetate comprises by way of non-limiting example, starches that are obtained by esterification of food starches with acetic anhydride or vinyl acetate and include starches that are identified by INS number 1420.

The term hydroxypropyl distarch phosphate by way of non-limiting example, starches that are obtained by esterification of unmodified food starch with sodium trimetaphosphate or phosphorus oxychloride combined with etherification by propylene oxide and include starches that are identified by INS number 1422.

The term hydroxypropyl starch comprises by way of non-limiting example, starches that are obtained by etherification of unmodified food starch with propylene oxide and include starches that are identified by INS number 1440.

The term hydroxypropyl distarch phosphate comprises by way of non-limiting example, starches that are obtained by esterification of unmodified food starch with sodium trimetaphosphate or phosphorus oxychloride combined with etherification by propylene oxide and include starches that are identified by INS number 1442.

The term starch sodium octenyl succinate comprises by way of non-limiting example, starches that are obtained by treatment of unmodified food starch with Octenylsuccinic anhydride and either sodium hydroxide or sodium carbonate as a pH buffer for neutralization and include starches that are identified by INS number 1450.

The term acetylated oxidized starch comprises by way of non-limiting example, starches that are obtained by treatment of food starch with sodium hypochlorite followed by esterification with acetic anhydride and include starches that are identified by INS number 1451.

The term Starch aluminum octenyl succinate comprises by way of non-limiting example, starches that are identified by INS number 1452.

The term toxicity refers to the potential of the super water absorbents to cause harmful effects on plants when it comes into contact with them. In biological testing, toxicity assessment involves evaluating the adverse effects of the super water absorbent.

The term biodegradability means the capacity of the super water absorbent to break down and assimilate by natural biological processes into simpler, environmentally benign substances. It involves the evaluation of how effectively the super water absorbent can be metabolized and decomposed by microorganisms and other living organisms present in the environment.

Accordingly, the present invention provides a super water absorbent polymer comprising: at least one acrylic acid or acrylate polymer chain; and at least one polyglucosyl polymer chain linked to the at least one acrylic acid or acrylate polymer chain.

In still another embodiment of the invention, the polyglucosyl polymer chain is present in an amount in the range of about 18 to about 90% by weight of the super water absorbent polymer.

In another embodiment of the invention, the polyglucosyl polymer chain comprises modified starch.

In still another embodiment of the invention, an aqueous solution containing 50% w/v of the polyglucosyl polymer chain has viscosity in the range of 5000-50000 cps at a room temperature.

In a further embodiment of the invention, the acrylic acid or acrylate polymer chain comprises acrylic acid monomer and a neutralizing agent.

In yet another embodiment of the invention, the acrylic acid or acrylate polymer chain comprises acrylic acid monomer neutralized to an extent of 40 to 90% by the neutralizing agent.

In a furthermore embodiment of the invention, the neutralizing agent is having an alkali metal cation. In another embodiment of the invention, the neutralizing agent is having a potassium metal cation. By way of non-limiting example, the neutralizing agent is selected from a group comprising sodium hydroxide, potassium hydroxide, and calcium hydroxide. By way of a non-limiting example, the neutralizing agent is potassium hydroxide.

In still another embodiment of the invention, the modified starch is selected from a group comprising an enzymatically modified starch, dextrinised starch, an acid treated starch, an alkali treated starch, a bleached starch, an oxidized starch, mono-starch phosphate, di-starch phosphate, phosphated di-starch phosphate, acetylated distarch phosphate, starch acetate,hydroxypropyl starch, hydroxypropyl distarch phosphate, starch sodium octenyl succinate, and acetylated oxidized starch; and preferably dextrinised starch, oxidized starch, and carboxy methylated starch; and more preferably dextrinised starch.

In a further embodiment of the invention, the super water absorbent polymer comprises a cross- linking agent in an amount of about 0.1 to about 1 % by weight of the super water absorbent polymer.

In an embodiment of the invention, the cross linker is selected from a group comprising methylene bis-acrylamide (MBA), Trimethylolpropane triacrylate (TMPTA), water, or a mixture thereof.

It is preferred to have the superabsorbent polymer in granular form and more particularly in the form of granules having particle size in the range of 600-1200 microns. The superabsorbent polymer in granular form having particle size in the range of 600 to 1200 microns is best suited for agricultural purposes. In particular, superabsorbent polymer in granular form having particle size in the range of 600 to 1200 microns can be easily mixed with commonly available fertilizers and applied to the land. Additionally, superabsorbent polymer in granular form having particle size in the range of 600 to 1200 microns can be easily mixed with the soil (for example during ploughing and leveling of the soil).

The present invention additionally provides a process for preparing the super water absorbent polymer, said process comprising: mixing one acrylic acid or acrylate monomer, a polyglucosyl polymer and a cross-linking agent under a polymerizing condition to obtain the super water absorbent polymer.

In a preferred embodiment, the present invention provides a process for preparation of a superabsorbent polymer by grafting reaction of modified starch with potassium polyacrylate in presence of a suitable crosslinker using a mixed initiator system.

In an embodiment of the invention, the process for preparing the super water absorbent polymer is carried out in a micro batch-wise manner (having a batch size of typically less than 1 kg), a macro batch-wise manner (typically having a batch size in excess of 2.5 kg) or in a continuous manner. Depending upon the manner of preparing the super water absorbent polymer (i.e. the micro batch-wise manner or the macro batch-wise manner the continuous manner), the sequence of introduction of the raw materials will vary. This aspect will be described in detail in the examples provided herein below.

In an embodiment of the invention, the process further comprises addition of at least one polymerization initiator, which may be selected from a group comprising Ammonium persulphate, or a mixed initiator system comprising of 0.02-0.10 wt% of redox including hydrogen peroxide solution and sodium ascorbate and 0.1-1.0wt% of ammonium persulfate.

In an embodiment of the invention, the “polymerizing condition” is includes an elevated temperature, preferably a temperature in a range of 55o to 85o C.

In an embodiment of the invention, at an end of the polymerization, wet super water absorbent polymer is wet, in which case, the wet super water absorbent polymer is subjected to drying, for example, air drying.

Thereafter, the dried super water absorbent polymer is formed into granules and more particularly granules having particle size in the range of 600-1200 microns. In this case, the dried super water absorbent polymer is cut into small pieces and thereafter subjected to grinding.

Experiment 1: Micro-Batch (Lab) Scale process for preparation of superabsorbent polymer:
Lab scale process was performed using different types of polyglucosyl polymers, typically native starches or modified starches such as, Guar Gum, Carboxy methyl Guar Gum, Oxidized Guar Gum, Sesbania Gum, Carboxymethyl Cellulose, Carboxymethyl Tamarid, Cassia Tora Gum, Topica Starch, Carboxy Methyl Starch Oxidized Starch/ Thin Boiling Starch, Maize Starch and Dextrinized Starch.

The process involved mixing the acrylic acid monomer, different types of starches (having different viscosities and in different weight percentage), a cross linker and a polymerization initiator in a kettle. The temperature was maintained at about 65oC to obtain hydrogel materials. The hydrogel materials were subsequently cooled to room temperature and cut into small pieces. Thereafter, the cut pieces were dried in a hot air oven. The dried hydrogel is grinded to have particle size of about 900 microns.

The acrylic acid monomer taken in these experiments was neutralized using potassium hydroxide to an extent of 90%. The cross-linker used in these examples was methylene bis-acrylamide (MBA). The amount of cross-linker used was 0.5 wt% of the weight of the super absorbent polymer. The polymerization initiator was Ammonium persulphate and an amount of initiator used was 0.5 wt%. The different types of starches used, the weight percentage of the starches in the super absorbent polymer, the viscosity of the starches which were used, and the water absorbency for the super absorbent polymer thus obtained is tabulated in Table 1 provided herein below:

Table 1: Results of Experiment 1
S. No Name / Type / Source of polyglucosyl polymer Viscosity Range Brookfield RVT SP #4, 20 RPM at 25 °C) w/w% of polyglucosyl polymer in the SAP Absorbency value
1 Guar Gum (1% w/v aq solution) 5000- 8000 cps 2% 280 g/g
2 Guar Gum (1% w/v aq solution) 5000- 8000 cps 5% 230 g/g
3 Carboxy methyl Guar Gum (1% w/v aq solution) 2000-4000 cps 2% 290 g/g
4 Carboxy methyl Guar Gum (1% w/v aq solution) 2000-4000 cps 5% 250 g/g
5 Oxidized Guar Gum (1% w/v aq solution) 50-100 cps 4% 300 g/g
6 Oxidized Guar Gum (1% w/v aq solution) 50-100 cps 8% 200 g/g
7 Sesbania Gum (1% w/v aq solution) 50 - 100 cps 2% 285 g/g
8 Sesbania Gum (1% w/v aq solution) 50 - 100 cps 5% 210 g/g
9 Carboxymethyl Cellulose (1% w/v aq solution)1000-2000 cps 5% 275 g/g
10 Carboxymethyl Tamarid (1% aq solution) 1000 - 2000 cps 5% 350g/g
11 Carboxymethyl Tamarid (1% aq solution) 1000 - 2000 cps 10% 260 g/g
12 Carboxymethyl Tamarid (8%w/v aq solution) 20000-40000 Cps 5% 330 g/g
13 Carboxymethyl Tamarid (8%w/v aq solution) 20000-40000 Cps 10% 250 g/g
14 Cassia Tora Gum (1%w/v aq solution, Hot & cold). 1000 - 1500 cps 5% 340 g/g
15 Cassia Tora Gum (1%w/v aq solution, Hot & cold). 1000 - 1500 cps 10% 270 g/g
16 Cassia Tora Gum (2% w/v aq solution, Hot & cold). 2000-3000 cps 5% 310 g/g
17 Cassia Tora Gum (2% w/v aq solution, Hot & cold). 2000-3000 cps 10% 250 g/g
18 Topica Starch (1% w/v aq solution, Hot & cold). 1000 - 2000 cps 10% 500 g/g
19 Topica Starch (1% w/v aq solution, Hot & cold). 1000 - 2000 cps 20% 425 g/g
20 Topica Starch (5% w/v aq solution, Hot & cold). 5,000-10,000 cps 10% 450 g/g
21 Topica Starch (5% w/v aq solution, Hot & cold). 5,000-10,000 cps 20% 400 g/g
22 Carboxy Methyl Starch (1% w/v aq solution, Hot & cold). 1000 - 2000 cps 10% 450 g/g
23 Carboxy Methyl Starch (1% w/v aq solution, Hot & cold). 1000 - 2000 cps 20% 375 g/g
24 Carboxy Methyl Starch (8% w/v aq solution, Hot & cold). 5000 - 10000 cps 10% 400 g/g
25 Carboxy Methyl Starch (8% w/v aq solution, Hot & cold). 5000 - 10000 cps 20% 350 g/g
26 Oxidized Starch/ Thin Boiling Starch (1% w/v aq solution, Hot & cold). 1000 - 2000 cps 10% 500 g/g
27 Oxidized Starch/ Thin Boiling Starch (1% w/v aq solution, Hot & cold). 1000 - 2000 cps 30% 425 g/g
28 Oxidized Starch/ Thin Boiling Starch (10% w/v aq solution, Hot & cold). 5000 - 10000 cps 10% 475 g/g
29 Oxidized Starch/ Thin Boiling Starch (10% w/v aq solution, Hot & cold). 5000 - 10000 cps 30% 400 g/g
30 Maize Starch (1% aq solution, Hot & cold). 1000 - 1500 cps 10% 600 g/g
31 Maize Starch (1% aq solution, Hot & cold). 1000 - 1500 cps 25% 450 g/g
32 Maize Starch (5% aq solution, Hot & cold). 2000 - 10000 cps 10% 250 g/g
33 Maize Starch (5% aq solution, Hot & cold). 2000 - 10000 cps 25% 150 g/g
34 Dextrinized Starch (1% w/v aq solution, Hot & cold). 1000 - 15000 cps 18% 480 g/g
35 Dextrinized Starch (50% w/v aq solution Hot & cold). 5,000-50,000 cps 18% 400 g/g

Thus, it was observed that almost all types / sources of the polyglucosyl polymer yielded super absorbent polymer.

All of the “Sources of polyglucosyl polymer” indicated in Table 1 were obtained from SHAANXI HAIBO BIOTECHNOLOGY CO., LTD. No.11 Tangyan South Road, Xian, Shaanxi, China.

When Native Guar gum was used as the sources of the polyglucosyl polymer, the weight percentage of Guar gum which could be used in the polymerization process was restricted to about 5%. Additionally, the Guar gum had to be diluted to a very large extent for use in the process. For instance, an aqueous solution containing 1 w/v of Guar gum had to be used. Attempts to use aqueous solutions having higher concentration of Guar gum did not yield uniform super absorbent polymer. Similar results were observed when Carboxy methyl Guar Gum (Modified Starch), carboxy Methyl Cellulose (Modified Cellulose), and Sesbania Gum (Native Starch) was used. When Oxidized Guar Gum (Modified Starch) was used, the weight percentage of Oxidized Guar Gum which could be used in the polymerization process increased marginally to about 8%. However, even the oxidized Guar Gum had to be diluted to a very large extent for use in the process. For instance, an aqueous solution containing 1 w/v % of Oxidized Guar Gum had to be used. Attempts to use aqueous solutions having higher concentration of Oxidized Guar Gum did not yield uniform super absorbent polymer.

It can be seen that except for Dextrinized starch, no other source of polyglucosyl polymer was able to incorporated in the SAP at a weight percentage in excess of even 30% w/w when an aqueous solution of the source of polyglucosyl polymer contained more than 10% w/v of the polyglucosyl polymer (Serial Number 29). On the other hand, Dextrinized starch could be incorporated in the SAP at a weight percentage in excess of even 30% w/w when an aqueous solution of the Dextrinized starch contained more than 10% w/v of the Dextrinized starch (Serial Number 35).

Experiment 2: Macro-Batch Scale process for preparation of superabsorbent polymer:
The same concept is applied for 7 kg batch process in CKR-10 reactor, with different starches/modified starches such as, Guar Gum, Carboxy methyl Guar Gum, Oxidized Guar Gum, Sesbania Gum, Carboxymethyl Cellulose, Carboxymethyl Tamarid, Cassia Tora Gum, Topica Starch, Carboxy Methyl Starch Oxidized Starch/ Thin Boiling Starch, Maize Starch and Modified Starch (Dextrinized Starch).

The process involved mixing the acrylic acid monomer, different types of starches (having different viscosities and in different weight percentage), a suitable crosslinker and a polymerization initiator inside the CKR batch reactor instead of kettle. Further, the porous superabsorbent polymer obtained is dried in a tray dryer using up flow and down flow of hot air at a temperature range of 80° C for 90 min, followed by subsequent grinding of the dried porous superabsorbent polymer to get the targeted granular superabsorbent polymer having particle size of 1100 microns.

The acrylic acid monomer taken in these experiments was neutralized using potassium hydroxide to an extent of 90%. The cross-linker used in these examples was methylene bis-acrylamide (MBA). The amount of cross-linker used was 0.5 wt% of the weight of the super absorbent polymer. The polymerization initiator was Ammonium persulphate and an amount of initiator used was 0.5 wt%. The different types of starches used, the weight percentage of the starches in the super absorbent polymer, the viscosity of the starches which were used, and the water absorbency for the super absorbent polymer thus obtained is tabulated in Table 2 provided herein below:

Table 2: Results of Experiment 2:

S.No Name / Type / Source of polyglucosyl polymer Viscosity Range Brookfield RVT SP #4, 20 RPM at 25 °C) w/w% of polyglucosyl polymer in the SAP Absorbency value
1 Guar Gum (1% w/v aqsolution) 5000- 8000 cps 2% Uniform Polymer not formed
2 Guar Gum (1% w/v aqsolution).5000- 8000 cps 5% Uniform Polymer not formed
3 Carboxy methyl Guar Gum (1% w/v aq solution).2000-4000 cps 2% 270 g/g
4 Carboxy methyl Guar Gum (1% w/v aq solution).2000-4000 cps 5% 230 g/g
5 Oxidized Guar Gum (1% w/v aq solution).50-100 cps 4% 280 g/g
6 Oxidized Guar Gum (1% w/v aq solution).50-100 cps 8% 170 g/g
7 Sesbania Gum (1% w/v aq solution). 50 - 100 cps 2% Uniform Polymer not formed
8 Sesbania Gum (1% w/v aq solution). 50 - 100 cps 5% Uniform Polymer not formed
9 Carboxymethyl Cellulose (1% w/v aq solution).1000-2000 cps 5% 250 g/g
10 Carboxymethyl Tamarid (1% aq solution). 1000 - 2000 cps 5% 330 g/g
11 Carboxymethyl Tamarid (1% aq solution). 1000 - 2000 cps 10% 240 g/g
12 Carboxymethyl Tamarid (8%w/vaq solution). 20000-40000 Cps 5% 310 g/g
13 Carboxymethyl Tamarid (8%w/vaq solution). 20000-40000 Cps 10% 230 g/g
14 Cassia Tora Gum (1%w/vaq solution, Hot & cold). 1000 - 1500 cps 5% Uniform Polymer not formed
15 Cassia Tora Gum (1%w/vaq solution, Hot & cold). 1000 - 1500 cps 10% Uniform Polymer not formed
16 Cassia Tora Gum (2% w/vaq solution, Hot & cold). 2000-3000 cps 5% Uniform Polymer not formed
17 Cassia Tora Gum (2% w/vaq solution, Hot & cold). 2000-3000 cps 10% Uniform Polymer not formed
18 Topica Starch (1% w/vaq solution, Hot & cold). 1000 - 2000 cps 10% Uniform Polymer not formed
19 Topica Starch (1% w/vaq solution, Hot & cold). 1000 - 2000 cps 20% Uniform Polymer not formed
20 Topica Starch (5% w/vaq solution, Hot & cold). 5,000-10,000 cps 10% Uniform Polymer not formed
21 Topica Starch (5% w/vaq solution, Hot & cold). 5,000-10,000 cps 20% Uniform Polymer not formed
22 Carboxy Methyl Starch (1% w/vaq solution, Hot & cold). 1000 - 2000 cps 10% 380 g/g
23 Carboxy Methyl Starch (1% w/vaq solution, Hot & cold). 1000 - 2000 cps 20% 340 g/g
24 Carboxy Methyl Starch (8% w/vaq solution, Hot & cold). 5000 - 10000 cps 10% 370 g/g
25 Carboxy Methyl Starch (8% w/vaq solution, Hot & cold). 5000 - 10000 cps 20% 300 g/g
26 Oxidized Starch/ Thin Boiling Starch (1% w/vaq solution, Hot & cold). 1000 - 2000 cps 10% 480 g/g
27 Oxidized Starch/ Thin Boiling Starch (1% w/vaq solution, Hot & cold). 1000 - 2000 cps 30% 400 g/g
28 Oxidized Starch/ Thin Boiling Starch (10% w/vaq solution, Hot & cold). 5000 - 10000 cps 10% 400 g/g
29 Oxidized Starch/ Thin Boiling Starch (10% w/vaq solution, Hot & cold). 5000 - 10000 cps 30% 350 g/g
30 Maize Starch (1% aq solution, Hot & cold). 1000 - 1500 cps 10% Uniform Polymer not formed
31 Maize Starch (1% aq solution, Hot & cold). 1000 - 1500 cps 25% Uniform Polymer not formed
32 Maize Starch (5% aq solution, Hot & cold). 2000 - 10000 cps 10% Uniform Polymer not formed
33 Maize Starch (5% aq solution, Hot & cold). 2000 - 10000 cps 25% Uniform Polymer not formed
34 Dextrinized Starch (1% w/v aq solution, Hot & cold). 1000 - 15000 cps 18% 480 g/g
35 Dextrinized Starch (50% w/v aq solution Hot & cold). 5,000-50,000 cps 18% 400 g/g

In many instances, Uniform Polymer not formed. Specifically, when native starches such as Guar Gum, Sesbania Gum, Cassia Tora Gum, Topica Starch, and Maize Starch displayed a tendency to generate distinct agglomerates, resulting in a lack of uniformity within the samples. Contrary to the above, use of the modified starches such as Carboxy methyl Guar Gum, Oxidized Guar Gum, Carboxymethyl Cellulose, Carboxymethyl Tamarid, Carboxy Methyl Starch, Oxidized Starch/ Thin Boiling Starch, and Dextrinized Starch resulted in formation of uniform polymer.

Generally, there was a dip in the absorbency values, the exception being Dextrinized Starch. Dextrinized Starch achieved absorbency value which was at par with what was obtained in Experiment 1.

Experiment 3: Continuous process for preparation of a superabsorbent polymer:
In continuous process only modified starches such as Carboxy methyl Guar Gum, Oxidized Guar Gum, Carboxymethyl Cellulose, Carboxymethyl Tamarid, Carboxy Methyl Starch, Oxidized Starch/ Thin Boiling Starch, and Dextrinized Starch were taken for preparation of a superabsorbent polymer (as the remaining options failed in Experiment 2). The continusous process comprises the steps of:
a) neutralising an acrylic acid with an alkali hydroxide at a temperature of 15-30 °C to a degree of neutralization in the range of 40-90%;
b) mixing a crosslinker to the neutralized acrylic acid to obtain a first reaction mass;
c) preparing an aqueous solution of modified starch having a concentration and viscosity as per Table 3;
d) mixing a crosslinker to the aqueous solution of starch to obtain a second reaction mass;
e) mixing the first reaction mass with the second reaction mass at 30-80 °C and further adding a mixed initiator system comprising of 0.02-0.10 wt% of redox including hydrogen peroxide solution and sodium ascorbate and 0.1-1.0wt% of ammonium persulfate for preparing a porous superabsorbent polymer; the quantity of the second reaction mass is such the wt/wt% of the starch is as per Table 3;
f) drying the porous super absorbent polymer obtained in the step e) under a tray dryer using up and down flow of hot air at a temperature range of 80-170 °C for 20-120 minutes; and
g) grinding the dried porous superabsorbent polymer obtained in the step f) to get the targeted granular superabsorbent polymer having particle size of 600-1200 microns.

The water absorbency for the super absorbent polymer thus obtained is tabulated in Table 3 provided herein below:

Table 3: Results of Experiment 3:

S.No Name / Type / Source of polyglucosyl polymer Viscosity Range Brookfield RVT SP #4, 20 RPM at 25 °C) w/w% of polyglucosyl polymer in the SAP Absorbency value
3 Carboxy methyl Guar Gum (1% w/v aq solution).2000-4000 cps 2% Uniform Polymer not formed
4 Carboxy methyl Guar Gum (1% w/v aq solution).2000-4000 cps 5% Uniform Polymer not formed
5 Oxidized Guar Gum (1% w/v aq solution).50-100 cps 4% Uniform Polymer not formed
6 Oxidized Guar Gum (1% w/v aq solution).50-100 cps 8% Uniform Polymer not formed
9 Carboxymethyl Cellulose (1% w/v aq solution).1000-2000 cps 5% Uniform Polymer not formed
10 Carboxymethyl Tamarid (1% aq solution). 1000 - 2000 cps 5% Uniform Polymer not formed
11 Carboxymethyl Tamarid (1% aq solution). 1000 - 2000 cps 10% Uniform Polymer not formed
12 Carboxymethyl Tamarid (8%w/vaq solution). 20000-40000 Cps 5% Uniform Polymer not formed
13 Carboxymethyl Tamarid (8%w/vaq solution). 20000-40000 Cps 10% Uniform Polymer not formed
22 Carboxy Methyl Starch (1% w/vaq solution, Hot & cold). 1000 - 2000 cps 10% Uniform Polymer not formed
23 Carboxy Methyl Starch (1% w/vaq solution, Hot & cold). 1000 - 2000 cps 20% Uniform Polymer not formed
24 Carboxy Methyl Starch (8% w/vaq solution, Hot & cold). 5000 - 10000 cps 10% Uniform Polymer not formed
25 Carboxy Methyl Starch (8% w/vaq solution, Hot & cold). 5000 - 10000 cps 20% Uniform Polymer not formed
26 Oxidized Starch/ Thin Boiling Starch (1% w/vaq solution, Hot & cold). 1000 - 2000 cps 10% Uniform Polymer not formed
27 Oxidized Starch/ Thin Boiling Starch (1% w/vaq solution, Hot & cold). 1000 - 2000 cps 30% Uniform Polymer not formed
28 Oxidized Starch/ Thin Boiling Starch (10% w/vaq solution, Hot & cold). 5000 - 10000 cps 10% Uniform Polymer not formed
29 Oxidized Starch/ Thin Boiling Starch (10% w/vaq solution, Hot & cold). 5000 - 10000 cps 30% Uniform Polymer not formed
34 Dextrinized Starch (1% w/v aq solution Hot & cold). 5,000-50,000 cps 18% Uniform Polymer not formed
35 Dextrinized Starch (50% w/v aq solution Hot & cold). 5,000-50,000 cps 18% 400 g/g

In many instances, Uniform Polymer not formed. Specifically, when Carboxy methyl Guar Gum, Oxidized Guar Gum, Carboxymethyl Cellulose, Carboxymethyl Tamarid, Carboxy Methyl Starch, and Oxidized Starch/ Thin Boiling Starch displayed a tendency to generate distinct agglomerates, resulting in a lack of uniformity within the samples. Contrary to the above, use of certain grades (especially the grades of Dextrinized Starch which had a viscosity of 5,000-50,000 cps (for an aqueous solution containing 50% w/v aq, Hot & cold) resulted in formation of uniform polymer while certain grades of (especially the grades of Dextrinized Starch which had a viscosity of 1,000-15,000 cps (for an aqueous solution containing 1% w/v of Dextrinized starch, Hot & cold) did not result in formation of uniform polymer.

Experiment 4: Continuous process for preparation of a superabsorbent polymer incorporating Dextrinized Starch at increasing wt/wt%:
A variety of Super absorbent polymers was prepared by a continuous process following the below described process:
a) neutralising an acrylic acid with an alkali hydroxide at a temperature of 30°C to a degree of neutralization in the range of 90%;
b) mixing a crosslinker to the neutralized acrylic acid to obtain a first reaction mass;
c) preparing an aqueous solution of modified starch; wherein the aqueous solution comprising 50% w/v of the modified starch has a viscosity in the range of 5000- 50000 cps at a room temperature;
d) mixing a crosslinker methylene bis-acrylamide (MBA) or Trimethylolpropane triacrylate (TMPTA) to the aqueous solution of modified starch to obtain a second reaction mass;
e) mixing the first reaction mass with the second reaction mass at 30-80 °C and further adding a mixed initiator system comprising of 0.02-0.10 wt% of redox including hydrogen peroxide solution and sodium ascorbate and 0.1-1.0wt% of ammonium persulfate for preparing a porous superabsorbent polymer; the quantity of the second reaction mass is such the wt/wt% of the starch is as per Table 4;
f) drying the porous superabsorbent polymer obtained in the step e) under a tray dryer using up and down flow of hot air at a temperature range of 80-170 °C for 20-120 minutes; and
g) grinding the dried porous superabsorbent polymer obtained in the step e) to get the targeted granular superabsorbent polymer having particle size of 600-1200 microns.

The water absorbency for the super absorbent polymer thus obtained is tabulated in Table 4 provided herein below:

Table 4: Results of Experiment 4:

Sample No Name / Type / Source of polyglucosyl polymer Viscosity Range Brookfield RVT SP #4, 20 RPM at 25 °C) w/w% of polyglucosyl polymer in the SAP Absorbency value
36 Dextrinized Starch (50% w/v aq solution Hot & cold). 5,000-50,000 cps 25% 390 g/g
37 Dextrinized Starch (50% w/v aq solution Hot & cold). 5,000-50,000 cps 30% 360 g/g
38 Dextrinized Starch (50% w/v aq solution Hot & cold). 5,000-50,000 cps 35% 330 g/g
39 Dextrinized Starch (50% w/v aq solution Hot & cold). 5,000-50,000 cps 40% 300 g/g
40 Dextrinized Starch (50% w/v aq solution Hot & cold). 5,000-50,000 cps 45% 260 g/g
41 Dextrinized Starch (50% w/v aq solution Hot & cold). 5,000-50,000 cps 50% 250 g/g
42 Dextrinized Starch (50% w/v aq solution Hot & cold). 5,000-50,000 cps 55% 240 g/g
43 Dextrinized Starch (50% w/v aq solution Hot & cold). 5,000-50,000 cps 60% 230 g/g
44 Dextrinized Starch (50% w/v aq solution Hot & cold). 5,000-50,000 cps 65% 210 g/g
45 Dextrinized Starch (50% w/v aq solution Hot & cold). 5,000-50,000 cps 70% 180 g/g

The data presented in Table 4 highlights a significant finding: uniform super absorbent polymer was being formed when the super absorbent polymer contained up to 70% of Dextrinized Starch. Additionally, the Absorbency value for all super absorbent polymer formed was consistently above 180 g/g.

In an embodiment of the invention, Figure 1 illustrates FTIR spectra of super absorbent polymer Sample 41 (50% w/w Dextrinized Starch (50% w/v aq solution Hot & cold). 5,000-50,000 cps), in accordance with an embodiment of the invention. The dried hydrogel then characterized using FTIR spectra. The FTIR spectra, confirms the presence of starch and polyacrylate. The presence of C=O in polyacrylate is confirms by stretching frequency at 1698 cm-1. The presence of O–H bending for starch is confirmed by stretching frequency at 1551 cm-1. Presence of C–H and C–O of starch and acrylate; N–H of crosslinker are confirmed by stretching frequency at 2935, 1401; and 1446 cm-1, respectively.

In an embodiment of the invention, Figure 1 illustrates TGA Spectra of super absorbent polymer Sample 41 (50% w/w Dextrinized Starch (50% w/v aq solution Hot & cold). 5,000-50,000 cps), in accordance with an embodiment of the invention. The thermo gravimetric analysis of the sample showed that the evolution moistures and volatiles: 0-150o C, monomers: 150-200o C, the degradation of starch derivative observed in the range between 200-350o C, further the grafted poly acrylate part degraded in the region of 350-500o C and the remain metal salt at ~900o C.

Experiment 5: Micro-Batch (Lab) Scale process for preparation of superabsorbent polymer:
A variety of Super absorbent polymers was prepared by a Lab scale process using differing quantities of Dextrinized Starch.

The process involved mixing the acrylic acid monomer, Dextrinized Starch (in quantities as mentioned in Table 5), a cross linker and a polymerization initiator in a kettle. The temperature was maintained at about 65oC to obtain hydrogel materials. The hydrogel materials were subsequently cooled to room temperature and cut into small pieces. Thereafter, the cut pieces were dried in a hot air oven. The dried hydrogel is grinded to have particle size of about 900 microns.

The acrylic acid monomer taken in these experiments was neutralized using potassium hydroxide to an extent of 90%. The cross-linker used in these examples was methylene bis-acrylamide (MBA). The amount of cross-linker used was 0.5 wt% of the weight of the super absorbent polymer. The polymerization initiator was Ammonium persulphate and an amount of initiator used was 0.5 wt%. The different types of starches used, the weight percentage of the starches in the super absorbent polymer, the viscosity of the starches which were used, and the water absorbency for the super absorbent polymer thus obtained is tabulated in Table 5 provided herein below:

Table 5: Results of Experiment 5:

Sample No Name / Type / Source of polyglucosyl polymer Viscosity Range Brookfield RVT SP #4, 20 RPM at 25 °C) w/w% of polyglucosyl polymer in the SAP Absorbency value
46 Dextrinized Starch (50% w/v aq solution Hot & cold). 5,000-50,000 cps 75% 170 g/g
47 Dextrinized Starch (50% w/v aq solution Hot & cold). 5,000-50,000 cps 80% 160 g/g
48 Dextrinized Starch (50% w/v aq solution Hot & cold). 5,000-50,000 cps 85% 150 g/g
49 Dextrinized Starch (50% w/v aq solution Hot & cold). 5,000-50,000 cps 90% 140 g/g

The data presented in Table 5 highlights a significant finding: uniform super absorbent polymer was being formed when the super absorbent polymer contained up to 90% of Dextrinized Starch. Additionally, the Absorbency value for all super absorbent polymer formed was consistently above 140 g/g.

It was also observed, when the starch amount was increased over 90%, the hydrogel formation is not good.

Experiment 6: Eco-Toxicity Tests by Soil bearing Bacteria and Fungi
Since the super absorbent polymer is primarily intended to be used in agricultural purposes, i.e. mixed with the soil where plants are growing, Eco-Toxicity Tests were performed on the super absorbent polymers prepared as per serial numbers 35 to 49.

Each of the super absorbent polymer as per serial numbers 35 to 49 was dissolved in hot water, yielding a saturated solution of the material. This solution was then subjected to agar cup method to determine toxicity towards Bacillus pumillus (ATCC14884), Bacillus megaterium (ATCC14581), Bacillus subtilis (ATCC6051), and Klebsiella sp. (MTCC Accession No. 13289), which are some of the soil borne plant growth promoting bacteria. Also, rigorous agar cup method to determine toxicity towards Colletotrichum sp. (MTCC Accession No. 3405), which is a soil borne plant growth promoting Fungi. The Eco-Toxicity of the super absorbent polymer is tabulated in Table 6 provided herein below:

Table 6: Results of Experiment 6:

Sample No Name of Organism Property of the Organism Toxicity
35 Bacillus pumillus Hormone Non-Toxic
36 Bacillus pumillus Hormone Non-Toxic
37 Bacillus pumillus Hormone Non-Toxic
38 Bacillus pumillus Hormone Non-Toxic
39 Bacillus pumillus Hormone Non-Toxic
40 Bacillus pumillus Hormone Non-Toxic
41 Bacillus pumillus Hormone Non-Toxic
42 Bacillus pumillus Hormone Non-Toxic
43 Bacillus pumillus Hormone Non-Toxic
44 Bacillus pumillus Hormone Non-Toxic
45 Bacillus pumillus Hormone Non-Toxic
46 Bacillus pumillus Hormone Non-Toxic
47 Bacillus pumillus Hormone Non-Toxic
48 Bacillus pumillus Hormone Non-Toxic
49 Bacillus pumillus Hormone Non-Toxic
35 Bacillus megaterium Phosphate Non-Toxic
36 Bacillus megaterium Phosphate Non-Toxic
37 Bacillus megaterium Phosphate Non-Toxic
38 Bacillus megaterium Phosphate Non-Toxic
39 Bacillus megaterium Phosphate Non-Toxic
40 Bacillus megaterium Phosphate Non-Toxic
41 Bacillus megaterium Phosphate Non-Toxic
42 Bacillus megaterium Phosphate Non-Toxic
43 Bacillus megaterium Phosphate Non-Toxic
44 Bacillus megaterium Phosphate Non-Toxic
45 Bacillus megaterium Phosphate Non-Toxic
46 Bacillus megaterium Phosphate Non-Toxic
47 Bacillus megaterium Phosphate Non-Toxic
48 Bacillus megaterium Phosphate Non-Toxic
49 Bacillus megaterium Phosphate Non-Toxic
35 Bacillus subtilis Nitrogen Non-Toxic
36 Bacillus subtilis Nitrogen Non-Toxic
37 Bacillus subtilis Nitrogen Non-Toxic
38 Bacillus subtilis Nitrogen Non-Toxic
39 Bacillus subtilis Nitrogen Non-Toxic
40 Bacillus subtilis Nitrogen Non-Toxic
41 Bacillus subtilis Nitrogen Non-Toxic
42 Bacillus subtilis Nitrogen Non-Toxic
43 Bacillus subtilis Nitrogen Non-Toxic
44 Bacillus subtilis Nitrogen Non-Toxic
45 Bacillus subtilis Nitrogen Non-Toxic
46 Bacillus subtilis Nitrogen Non-Toxic
47 Bacillus subtilis Nitrogen Non-Toxic
48 Bacillus subtilis Nitrogen Non-Toxic
49 Bacillus subtilis Nitrogen Non-Toxic
35 Klebsiella sp Potassium Non-Toxic
36 Klebsiella sp Potassium Non-Toxic
37 Klebsiella sp Potassium Non-Toxic
38 Klebsiella sp Potassium Non-Toxic
39 Klebsiella sp Potassium Non-Toxic
40 Klebsiella sp Potassium Non-Toxic
41 Klebsiella sp Potassium Non-Toxic
42 Klebsiella sp Potassium Non-Toxic
43 Klebsiella sp Potassium Non-Toxic
46 Klebsiella sp Potassium Non-Toxic
47 Klebsiella sp Potassium Non-Toxic
48 Klebsiella sp Potassium Non-Toxic
49 Klebsiella sp Potassium Non-Toxic
39 Colletotrichum sp. - Non-Toxic
40 Colletotrichum sp. - Non-Toxic
41 Colletotrichum sp. - Non-Toxic
42 Colletotrichum sp. - Non-Toxic
43 Colletotrichum sp. - Non-Toxic
44 Colletotrichum sp. - Non-Toxic
45 Colletotrichum sp. - Non-Toxic
46 Colletotrichum sp. - Non-Toxic
47 Colletotrichum sp. - Non-Toxic
48 Colletotrichum sp. - Non-Toxic
49 Colletotrichum sp. - Non-Toxic

None of the super absorbent polymers prepared as per serial numbers 35 to 49 showed toxicity towards any of the 5 micro organisms.

Experiment 7: Bio-Degradability tests
Since the super absorbent polymer is primarily intended to be used in agricultural purposes, i.e. mixed with the soil where plants are growing, bio-degradability Tests were performed on the super absorbent polymers prepared as per serial numbers 35 to 49 as per ISO 17556:2019. The bio-Degradability of the super absorbent polymer is tabulated in Table 7 provided herein below:

Table 7: Results of Experiment 7:

Sample No Percentage Bio-Degradation
35 27.3% within 3 months
36 37.2% within 3 months
37 41.7% within 3 months
38 46.5% within 3 months
39 49.8% within 3 months
40 58.2% within 3 months
41 72.6% within 3 months
42 89.4% within 2 months
43 100% within 5 weeks
44 100% within 5 weeks
45 100% within 5 weeks
46 100% within 5 weeks
47 100% within 5 weeks
48 100% within 5 weeks
49 100% within 5 weeks

Thus, all the super absorbent polymers thus tested showed high degradation.

Experiment 8: Field tests to determine the effect of growing a variety of crops in soil containing the super absorbent polymers
Field Test 1:
In the Field Test 1, two fields each of having a size of 1000 m2 were prepared. In the first field, 25kg of DAP was applied and in the second field, 25kg of DAP and 5kg of Sample 35 was applied. In the summer season, Guar plant was then grown in both the fields and the results thus obtained is tabulated in Table 8 provided herein below:

Table 8: Results of Field Test 1:

25 kg DAP (Control) 25 kg DAP + 5 kg of Sample 35 % increase Positive impact on yield (Population + Seeds / Branches)
Population (5m) 8.21 11.24 36.84 36.84
No. of Seeds 9.06 9.97 10.12 10.12
% Increase in Yield 46.96

Conclusion: Thus it can be seen that when sample 35 was applied to the land, the percentage increase in yield in Guar is about 47%.

Field Test 2:
In the Field Test 2, two fields each of having a size of 1000 m2 were prepared. In the first field, 25kg of DAP was applied and in the second field, 25kg of DAP and 5kg of Sample 36 was applied. In the summer season, Bajra plant was then grown in both the fields and the results thus obtained is tabulated in Table 9 provided herein below:

Table 9: Results of Field Test 2:

25 kg DAP (Control) 25 kg DAP + 5 kg of Sample 36 % increase Positive impact on yield (Population + Tillers)
Population (5m) 6.27 10.13 61.46 61.46
No. of Tillers 2.53 3.43 35.53 35.53
% Increase in Yield 96.98

Conclusion: Thus it can be seen that when sample 36 was applied to the land, the percentage increase in yield in Bajra is about 97%.

Field Test 3:
In the Field Test 3, two fields each of having a size of 1000 m2 was prepared. In the first field, 25kg of DAP was applied and in the second field, 25kg of DAP and 5kg of Sample 37 was applied. In the summer season, Mung (Lentils) plant was then grown in both the fields and the results thus obtained are tabulated in Table 10 provided herein below:

Table 10: Results of Field Test 3:

25 kg DAP (Control) 25 kg DAP + 5 kg of Sample 36 % increase Positive impact on yield (Population + Seeds)
Population (5m) 8.56 10.99 28.45 28.45
No. of Seeds 9.99 11.27 12.82 12.82
% Increase in Yield 41.27

Conclusion: Thus it can be seen that when sample 37 was applied to the land, the percentage increase in yield in Mung is about 41%.

Field Test 4:
In the Field Test 4, two fields each of having a size of 1000 m2 was prepared. In the first field, 25kg of DAP was applied and in the second field, 25kg of DAP and 5kg of Sample 38 was applied. In the summer season, Cotton plant was then grown in both the fields and the results thus obtained is tabulated in Table 11 provided herein below:

Table 11: Results of Field Test 4:
25 kg DAP (Control) 25 kg DAP + 5 kg of Sample 36 % increase Positive impact on yield (Population + Tillers)
Population (5m) 6.35 8.16 28.36 28.36
No. of Branches 19.24 22.76 18.30 18.30
% Increase in Yield 46.65

Conclusion: Thus it can be seen that when sample 38 was applied to the land, the percentage increase in yield cotton is about 47%.

Field Test 5:
In the Field Test 5, two fields each of having a size of 1000 m2 was prepared. In the first field, 25kg of DAP was applied and in the second field, 25kg of DAP and 5kg of Sample 39 was applied. In the winter season, Mustard plant was then grown in both the fields and the results thus obtained is tabulated in Table 12 provided herein below:

Table 12: Results of Field Test 5:
25 kg DAP (Control) 25 kg DAP + 5 kg of Sample 36 % increase
Average of Population (3m) 20.74 25.52 23.02
Average of Height 83.39 94.00 12.71
Average No. of Leaves 16.64 22.36 34.33

Conclusion: Thus it can be seen that when sample 39 was applied to the land, all the properties of the mustard plant increased substantially.

Field Test 6:
In the Field Test 6, two fields each of having a size of 1000 m2 was prepared. In the first field, 25kg of DAP was applied and in the second field, 25kg of DAP and 5kg of Sample 40 was applied. In the winter season, wheat plant was then grown in both the fields and the results thus obtained is tabulated in Table 13 provided herein below:

Table 13: Results of Field Test 6:
25 kg DAP (Control) 25 kg DAP + 5 kg of Sample 36 % increase
Average of Population (1m) 41.52 49.21 18.53
Average of Height (cm) (152) 22.10 26.43 19.56
Average No. of Tillers (44) 4.14 5.31 28.41
Average of Tiller/meter (10) 90.43 117.80 30.27

Conclusion: Thus it can be seen that when sample 40 was applied to the land, all the properties of the wheat plant increased substantially.

Field Test 7:
In the Field Test 7, two fields each of having a size of 1000 m2 was prepared. In the first field, 25kg of DAP was applied and in the second field, 25kg of DAP and 5kg of Sample 41 was applied. In the winter season, gram plant was then grown in both the fields and the results thus obtained is tabulated in Table 14 provided herein below:

Table 14: Results of Field Test 7:
25 kg DAP (Control) 25 kg DAP + 5 kg of Sample 36 % increase
Average of Plant population /2 meter 15.06 18.85 25.15
Average of Plant height (cm) (9) 17.42 20.61 18.31
Average of Number of branches/plant (2) 6.40 7.80 21.88

Conclusion: Thus it can be seen that when sample 41 was applied to the land, all the properties of the gram plant increased substantially.

Field Test 8:
In the Field Test 8, two fields each of having a size of 1000 m2 was prepared. In the first field, 25kg of DAP was applied and in the second field, 25kg of DAP and 5kg of Sample 42 was applied. Potato plant was then grown (in the month of August) in both the fields and the results thus obtained are tabulated in Table 15 provided herein below:

Table 15: Results of Field Test 8:
25 kg DAP (Control) 25 kg DAP + 5 kg of Sample 36 % increase
Average of No. of Stem per Tuber (27) 4.92 6.52 32.61
Average of Height (cm) 45.35 51.04 12.54

Conclusion: Thus it can be seen that when sample 42 was applied to the land, all the properties of the potato plant increased substantially.

Field Test 9:
In the Field Test 9, two fields each of having a size of 1000 m2 was prepared. In the first field, 25kg of DAP was applied and in the second field, 25kg of DAP and 5kg of Sample 43 was applied. Pea plant was then grown (in the month of August) in both the fields and the results thus obtained are tabulated in Table 16 provided herein below:

Table 16: Results of Field Test 9:

25 kg DAP (Control) 25 kg DAP + 5 kg of Sample 36 % increase
Average of Plant Height (cm) 52.18 61.27 17.43
Average of No. of Shoots/ plant 2.38 2.47 3.98

Conclusion: Thus it can be seen that when sample 43 was applied to the land, all the properties of the pea plant increased substantially.

Field Test 10:
In the Field Test 10, two fields each of having a size of 1000 m2 was prepared. In the first field, 25kg of DAP was applied and in the second field, 25kg of DAP and 5kg of Sample 45 was applied. Tomato plant was then grown (in the month of August) in both the fields and the results thus obtained are tabulated in Table 17 provided herein below:

Table 17: Results of Field Test 10:
25 kg DAP (Control) 25 kg DAP + 5 kg of Sample 36 % increase
Average of Height (cm) 39.21 45.77 16.72

Conclusion: Thus it can be seen that when sample 45 was applied to the land, the average height of the tomato plant increased substantially.

Field Test 11:
In the Field Test 11, two fields each of having a size of 1000 m2 was prepared. In the first field, 25kg of DAP was applied and in the second field, 25kg of DAP and 5kg of Sample 46 was applied. Carrot plant was then grown (in the month of August) in both the fields and the results thus obtained are tabulated in Table 18 provided herein below:

Table 18: Results of Field Test 11:
25 kg DAP (Control) 25 kg DAP + 5 kg of Sample 36 % increase
Average of Root length (cm) 20.34 23.61 16.08
Average of Shoot length (cm) 70.81 75.46 6.56

Conclusion: Thus it can be seen that when sample 46 was applied to the land, all the properties of Carrot plant increased substantially.

Field Test 12:
In the Field Test 12, two fields each of having a size of 1000 m2 was prepared. In the first field, 25kg of DAP was applied and in the second field, 25kg of DAP and 5kg of Sample 48 was applied. Cauliflower plant was then grown (in the month of August) in both the fields and the results thus obtained are tabulated in Table 109 provided herein below:

Table 19: Results of Field Test 12:
25 kg DAP (Control) 25 kg DAP + 5 kg of Sample 36 % increase
Average of Leaves 16.80 18.98 12.98
Average of Leaf lenth (cm) 52.28 60.60 15.91

Conclusion: Thus it can be seen that when sample 48 was applied to the land, all the properties of Cauliflower plant increased substantially.

Field Test 13:
In the Field Test 13, two fields each of having a size of 1000 m2 was prepared. In the first field, 25kg of DAP was applied and in the second field, 25kg of DAP and 5kg of Sample 49 was applied. Onion plant was then grown (in the month of August) in both the fields and the results thus obtained are tabulated in Table 20 provided herein below:

Table 20: Results of Field Test 13:

25 kg DAP (Control) 25 kg DAP + 5 kg of Sample 36 % increase
Average of Leaf length (cm) 18.6 22.3 19.89

Conclusion: Thus it can be seen that when sample 49 was applied to the land, the average of leaf length of Onion plant increased substantially.

From Field Trials as undertaken, it was observed that all of the super absorbent polymers thus obtained increased one or more properties of the plant.

Advantages of the present invention:
One of the advantages of the present invention is the super absorbent polymer’s Exceptional Water Absorption capacity. The super water absorbent polymer, with its three-dimensional crosslinked network structure, exhibits an extraordinary ability to absorb water. It can absorb several hundred times its dry weight in water, making it highly effective in retaining and storing moisture.

An advantage of the present invention is the Effective Moisture Retention capacity. The polymer's exceptional water absorption capacity translates into superior moisture retention properties, which can significantly reduce the frequency of irrigation and maintain optimal soil moisture levels for extended periods.

Yet an advantage of the present invention is the Enhanced Soil Permeability. The Super water absorbents based on acrylic acid or acrylate polymers possess excellent permeability, allowing water and nutrients to move through the polymer structure and reach plant roots efficiently.

Still an advantage of the present invention is Customizable Formulations. The ability to incorporate natural polymers into the super water absorbent formulation offers a customizable approach. This allows tailoring the product's properties to specific plant and soil types, optimizing its performance for diverse agricultural and horticultural applications.

A further advantage of the present invention is Sustainable Solution: By incorporating a significant proportion of natural polymer content (more than 15 wt%), the product takes a step towards improved biodegradability. This addresses environmental concerns associated with non-biodegradable materials commonly used in super water absorbents.

Another advantage of the present invention is Long-Term Nutrient Delivery: The product's unique capacity to load plant nutrients and gradually release them into the soil over time promotes consistent and sustained nourishment for plants, supporting healthy growth and development. A further advantage of the present invention is Reduced Irrigation Demand. The advanced water absorption and retention capabilities of the super water absorbent can lead to substantial water savings, making it an environmentally friendly and water-efficient choice for agriculture and gardening.

Another advantage of the present invention is Compatibility with Soil Mixing. The controlled release of plant nutrients upon mixing the super water absorbent with soil aligns with best practices for efficient nutrient management. This method ensures that plants receive nutrients gradually and as needed, minimizing wastage.

While specific language has been used to describe the disclosure, any limitations arising on account of the same are not intended. As would be apparent to a person in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein.
,CLAIMS:WE CLAIM:

1. A super water absorbent polymer comprising:
at least one acrylic acid or acrylate polymer chain; and
18 to 90% w/w of at least one polyglucosyl polymer chain linked to the at least one acrylic acid or acrylate polymer chain.

2. The super water absorbent polymer as claimed in claim 1, wherein the polyglucosyl polymer chain comprises a modified starch.

3. The super water absorbent polymer as claimed in claim 1, wherein an aqueous solution containing 50% w/v of the polyglucosyl polymer chain has viscosity in the range of 5000-50000 cps at a room temperature.

4. The super water absorbent polymer as claimed in claim 1, wherein the acrylic acid or acrylate polymer chain comprises acrylic acid monomer neutralized to an extent of 40 % to 90% by the neutralizing agent

5. The super water absorbent polymer as claimed in claim 4, wherein the neutralizing agent is having an alkali metal cation.

6. The super water absorbent polymer as claimed in claim 5, wherein the neutralizing agent is having a potassium metal cation.

7. The super water absorbent polymer as claimed in claim 1, wherein the modified starch is selected from a group comprising an enzymatically modified starch, dextrinised starch, an acid treated starch, an alkali treated starch, a bleached starch, an oxidized starch, mono-starch phosphate, di-starch phosphate, phosphated di-starch phosphate, acetylated distarch phosphate, starch acetate, hydroxypropyl starch, hydroxypropyl distarch phosphate, starch sodium octenyl succinate, and acetylated oxidized starch; and preferably dextrinised starch, oxidized starch, and carboxy methylated starch; and more preferably dextrinised starch.

8. The super water absorbent polymer as claimed in claim 1, wherein the super water absorbent polymer comprises a cross-linking agent in an amount of about 0.1 to about 1 % by weight of the super water absorbent polymer.

9. A process for preparing a super water absorbent polymer comprising:
mixing of acrylic acid or acrylate monomer with a polyglucosyl polymer in presence of a cross-linking agent under a polymerizing condition to obtain the super water absorbent polymer, the polyglucosyl polymer being present in an amount in the range of 18 to 90% w/w of the super water absorbent polymer.

10. The process as claimed in claim 9, wherein the polyglucosyl polymer chain comprises a modified starch selected from a group comprising an enzymatically modified starch, dextrinised starch, an acid treated starch, an alkali treated starch, a bleached starch, an oxidized starch, mono-starch phosphate, di-starch phosphate, phosphated di-starch phosphate, acetylated distarch phosphate, starch acetate, hydroxypropyl starch, hydroxypropyl distarch phosphate, starch sodium octenyl succinate, and acetylated oxidized starch; and preferably dextrinised starch, oxidized starch, and carboxy methylated starch; and more preferably dextrinised starch.

11. The process as claimed in claim 9, comprising addition of at least one polymerization initiator selected from a group comprising Ammonium persulphate, or a mixed initiator system comprising of 0.02-0.10 wt% of redox including hydrogen peroxide solution and sodium ascorbate and 0.1-1.0wt% of ammonium persulfate.

12. The process as claimed in claim 9, wherein at an end of the polymerization, wet super water absorbent polymer thus obtained is wet and the same is subjected to drying.

13. The process as claimed in claim 12, wherein dried super water absorbent polymer is formed into granules having particle size in the range of 600-1200 microns.