FIELD OF THE INVENTION
[001] The present invention relates to environment friendly modified grafted PVC polymer with less chlorine as a substitute for PVC, and a process of preparation thereof.
BACKGROUND AND PRIOR ARTS 5
[002] PVC is a well known polymer which is used in many purposes like construction, pipes, cables, sheets making etc. PVC contains chlorine and at higher temperature or after continuous longer use of it, materials made of PVC can leach some toxic chlorine atoms or molecules in the environment. In this work PVC has been modified in such a way so that chlorine atoms have been eliminated 10 and replaced up to great extent and thermal stability of modified PVC polymer is also maintained for using as a substitute in place of PVC in different applications.
[003] PVC is made from vinyl chloride monomer known usually by its initials VCM through polymerisation. Some monomers exist in the form of reactive 15 gaseous chemical substances, and some of these may cause health hazards when in direct contact with humans. In these cases they are manufactured and processed under strict control for health, safety and environmental protection. On the other hand, polymers such as PVC, which are manufactured from monomers through polymerisation, are solid and chemically stable substances, therefore do not affect 20 human health. VCM, which is the raw material for PVC, is a gas at ambient temperature but is usually stored in liquid form under pressure. Ethylene and chlorine are raw materials for PVC. The suppliers for these materials include producers of basic petrochemicals, which supply ethylene, and the chlor-alkali or caustic soda industry, which supplies chlorine. 25
[004] By thermal cracking of naphtha or natural gas, the basic petrochemical industry manufactures ethylene and propylene, etc. Naphtha is mainly supplied from the petroleum refinery industry, which uses crude oil as raw material. The
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chlor-alkali industry produces caustic soda, chlorine and hydrogen via electrolysis using industrial grade salt as main raw material. All these industries, by far, are polluting.
[005] At a first stage in the PVC production process ethylene and chlorine are combined to produce an intermediate product called ethylene dichloride; this is 5 then transformed into vinyl chloride, the basic building block of polyvinyl chloride or PVC. The process of `polymerisation' links together the vinyl chloride molecules to form chains of PVC. The PVC produced in this way is in the form of a white powder, not used alone, but blended with other ingredients to give formulations for wide ranges of products including but not limited to utensils, 10 pipes or the likes. PVC formulations have a wide range of applications including the most sensitive, such as medical equipment, plus construction, automotive and electrical cabling.
[006] Most commodity plastics have carbon and hydrogen as their main component elements whereas PVC contains around 57 per cent by weight of 15 chlorine (Cl) as well as carbon and hydrogen. The presence of chlorine in the molecule makes PVC particularly versatile because it makes it compatible with a wide range of other materials. The chlorine content also helps to make PVC flame retardant. It can also be used as a `marker' to distinguish PVC in automatic sorting systems for plastics recycling. PVC formulations can be shaped by a variety of 20 techniques and, using very little energy, made into the final product form. PVC polymer is chemically stable, neutral and non-toxic.
[007] In the earlier review work titled “A review on poly (vinyl chloride) and its modification by crosslinking and grafting”, the inventors stated that such PVC has limited uses but by adding various additives like plasticizers or by doing some 25 chemical modifications, its properties are altered up to great extent. Various studies on PVC and its modification have been reviewed in this paper. FT-IR and TGA/DT A have been mainly used for the characterization. Thermal stability of the modified PVC was observed to be increased in maximum studies but in some
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cases it decreased after crosslinking. Properties of the PVC has been altered up to desired extent by using bi-functional cross-linkers to find wide applications like in construction, household applications, biomedical applications etc.
[008] The original peer-review research paper form the same inventors titled “Study of Grafted Products of cross-linked Polymer of PVC and Multi-functional 5 amines”, it has been stated that the PVC is modified by using multifunctional amines ethylenediamine, diethylenetriamine and ethanolamine as a crosslinker in dimethylformamide. Reaction variables were optimized for getting desired crosslinked polymer which was further reacted with maleic anhydride to form graft polymer. The grafted product was hydrolyzed which on further hydrolysis 10 gives carboxylic group. This carboxylic group may react further with alcoholic group or acid chloride to give a new product. The grafted polymers were characterized by FT-IR-spectroscopy & thermal analysis (TGA/DTA). Swelling behavior of the modified polymers was examined in acidic, alkaline and neutral salt solutions. Cross linked polymers have also shown good absorption capacities 15 in acidic media.
[009] The same author group in yet another publication titled, “Modification of PVC with amino compound and its characterization”, notes that the PVC was modified by using bifunctional amines ethylenediamine, as a crosslinker in dimethylformamide. Reaction variables were optimized for getting desired 20 crosslinked polymer which was further reacted with maleic anhydride to form graft polymer.This product has shown good substitution of carboxylic group into polymer back bone of PVC. The grafted polymers werecharacterized by FT-IR spectroscopy & thermal analysis(TGA/DTA). Swelling behavior of the modified polymers was examined in acidic, alkaline andneutral salt solutions. Cross linked 25 polymers have shown good absorption capacities in neutral and acidic media. Due to good thermal stability and absorption capacities, these polymers might find applications in chromatography.
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[0010] US Patent no. 5338803A mentioned about modified chlorinated polyethylene (CPE) for use as an impact modifier for polyvinyl chloride, comprising a thermoplastic grafted CPE prepared by polymerizing compatible monomers or comonomers, i.emethyl methacrylate/styrene, methylmethacrylate or vinyl acetate, onto the CPE backbone via an aqueous slurry suspension 5 polymerization and the process of producing the cited modified chlorinated polyethylene.
[0011] US 4298714A provides a new polymeric composition of matter. Furthermore, the invention relates to these modifications of polyvinyl-chloride (P.V.C.) by reaction with certain thiol-group containing etheric or thioetheric 10 compounds, to form a family of novel chlorine, sulfur and/or oxygen containing polymers.
[0012] CN 201410370195.9 discloses the environmentally-friendly PA66 plastic material characterized by comprising the following substances in parts by weight: 31-40 parts of PA66 resin, 11-16 parts of polyvinyl chloride resin, 15-26 parts of 15 maleic anhydride grafted polypropylene, 14-28 parts of polyethylene glycol terephthalate, 9-13 parts of nanometer oxide, 8-14 parts of filler, 3-7 parts of alcohol-soluble resin, 3-5 parts of polyvinyl butyral, 9-17 parts of polypropylene, 3-5 parts of normal butanol, 4-7 parts of a halogen-free flame retardant and 9-14 parts of zinc stearate. The plastic modified material disclosed by the invention has 20 good flame retardant property, strong safety, good mechanical properties, good tensile strength, bending strength, shock strength, anti-thermal deformation temperature and the like, and an electronic connector prepared from the environmentally-friendly PA66 plastic material is strong in flame retardant property and long in service life. 25
[0013] As earlier mentioned, PVC is produced by polymerization of VCM. The main polymerization methods include suspension, emulsion, and bulk methods, wherein about 80% of production involves suspension polymerization. First, the raw material VCM is pressurized and liquefied, and then fed into the
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polymerization reactor, which contains water and suspending agents in advance. Next, the initiator is fed into the reactor, and PVC is produced under a few bars at 40 – 60°C.
[0014] The role of water is to remove and control the heat given off in the polymerization process. PVC forms as tiny particles which grow and when they 5 reach a desired size the reaction is stopped and any unreacted vinyl chloride is distilled off and re-used. The PVC is separated off and dried to form a white powder also known as PVC resin. Emulsion polymerization produces finer resin grades having much smaller particles, which are required by certain applications.
[0015] In the present invention, a new modified polymer is a better substitute of 10 PVC, which is having almost same stability and minimum chlorine content. Almost 90-95% Chlorine atoms are removed due to which it becomes environmental friendly. In this modification process cost may be about 20% more than simple original PVC but in the today’s scenario, environmental concern is important so this process and product can easily find application in polymer 15 industry as a better substitute for PVC.
Drawbacks in the existing state of art:
[0016] For getting modified crosslinked and grafted Polymer of PVC, it is first modified by crosslinking of selected bifunctional amines like ethanolamine and di-ethytriamine in dioxane and DMF solvent in the presence of basic medium. In 20 basic medium elimination of chlorine atoms take place easily at about 110°C-120°C which are attached to backbone of PVC. Crosslinked PVC is further grafted to get modified PVC with minimum Cl atoms So obtained product was characterised with thermal analysis (TGA/ DTA) which shows almost same thermal stability of modified polymer. While FT-IR shows the confirmation of 25 new product formed. By analytical techniques, it is also determined that Cl content is reduced by more than 90% as compared to original PVC polymer.
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OBJECTS OF THE INVENTION
[0017] The principal object of the invention is modification of Poly (Vinyl Chloride) by appropriate crosslinking and grafting techniques to get thermally stable substitute for PVC with very less chlorine.
[0018] Another object of the present invention is to design a process of 5 modification of Poly (Vinyl Chloride) by appropriate crosslinking and grafting techniques to get thermally stable substitute for PVC with very less chlorine.
[0019] Yet another object of the present invention is to disclose a process of preparation of an environment friendly substitute for PVC with much reduced chlorine content. 10
SUMMARY OF THE INVENTION
[0020] The present invention discloses and claims a process of preparation of an environment friendly substitute for PVC comprising the steps of dissolving PVC 15 powder in dioxane/ DMF at 400C with stirring on a magnetic stirrer for 3-8 hours 50ºC in order to obtain a clear 5-50 (w/v) % solution; adding concentrated alcoholic KOH solution 5-20%; crosslinking 90-95% aqueous solution of selected bifunctional amines such as ethanolamine, ethylene diamine, di-ethytriamine, di-ethytriamine in dioxane, washing in dioxane or DMF solvent wherein said amine 20 was added with vigorous stirring and the temperature was raised step wise to (80±5)ºC, (100±5) ºC and (120±5) ºC in order to remove unreacted PVC followed by drying; and modifying said cross linked PVC as obtained through reacting it with 20% to 100% w/w of maleic anhydride with respect to said cross-linked PVC in presence of 0.1 N sodium hydroxide solution; and final filtering, washing and 25 drying in oven at 60°C. 1 gm of crosslinked PVC was taken in the 25 ml DMF in round bottom flask prior reacting it with maleic anhydride. The step of
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modification was performed by stirring reaction mixture at 60°C for 1 hour so that polymer becomes soft, and ready for reaction in said step of modification.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
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Fig. 1: FT-IR of original PVC Polymer
Fig. 2: FT-IR of modified polymer
Fig. 3: TGA/DTA of PVC
Fig. 4: TGA/DTA of modified Polymer
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DETAILED DESCRIPTION OF THE INVENTION
[0021] At the very outset of the detailed description, it may be understood that the ensuing description only illustrates a particular form of this invention. However, such a particular form is only exemplary embodiment, and without intending to imply any limitation on the scope of this invention. Accordingly, the description is 15 to be understood as an exemplary embodiment and teaching of invention and not intended to be taken restrictively.
[0022] Throughout the description and claims of this specification, the phrases “comprise” and “contain” and variations of them mean “including but not limited to”, and are not intended to exclude other moieties, additives, components, 20 integers or steps. Thus, the singular encompasses the plural unless the context otherwise requires. Wherever there is an indefinite article used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.
[0023] Features, integers, characteristics, compounds, chemical moieties or 25 groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of
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the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends 5 to any novel one, or any novel combination, of the features disclosed in this specification including any accompanying claims, abstract and drawings or any parts thereof, or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
[0024] The reader's attention is directed to all papers and documents which are 10 filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. Post filing patents, original peer reviewed research paper shall be published. 15
[0025] Figure-1 depicts characteristic FT-IR spectrum of original unmodified PVC polymer by which polymer is characterized. From spectrum we observed sharp band at around 700cm-1, which might be characteristic of C-Cl stretching vibration. Bands in the range of 800-1350 cm-1 correspond to C-C stretching vibrations while band around 2950 cm-1 might be due to -C-H stretching 20 vibration. Bands corresponding to deformation or bending vibration of -C-H bond might be at 1430 cm-1.
[0026] Figure-2 depicts IR spectra of modified PVC with diethylenetriamine. The IR spectrum has absorption bands which are characteristics of specific bonds formed as a result of crosslinking with diethylenetriamine. IR bands around 3310 25 cm-1 & 1650 cm-1 appear due to secondary N-H stretching vibration and N-H in plane bending vibrations respectively, while band around 1200 cm-1 might be due to C-N stretching vibration in the crosslinked molecule. Extra band around 1600 cm-1 might be due to creation of some C=C bonds as a result of
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dehydohalogenation reaction in the polymer. Band at 3050 cm-1 corresponds to CH
stretching vibration.
[0027] Fig-3 and 4 show thermal characterisation of original and modified
polymers respectively. Thermal behaviour of the modified polymer was studied
by TGA/DTA analysis. From the thermal curves, w 5 e observe that crosslinked
polymer looses its mass at the slower rate as compared to simple PVC but
modified polymer is having lower softening point/ glass transition temperature as
compared original PVC. By this characterization we observe that thermal stability
is increased or almost maintained by crosslinking of amine compounds into PVC,
10 which suggest suitability of modified polymer for high temperature range also in
place of already existing PVC.
[0028] As earlier mentioned, for getting modified crosslinked and grafted
Polymer of PVC, it is first modified by crosslinking of selected bifunctional
amines like ethanolamine and di-ethytriamine in dioxane and DMF solvent in the
15 presence of basic medium. In basic medium elimination of chlorine atoms take
place easily at about 110°C-120°C, which are attached to backbone of PVC.
Crosslinked PVC is further grafted to get modified PVC with minimum Cl- atoms
So obtained product was characterised with thermal analysis (TGA/DTA) which
shows almost same thermal stability of modified polymer. While FT-IR shows the
20 confirmation of new product formed. By analytical techniques, it is also
determined that Cl content is reduced by more than 90% as compared to original
PVC polymer.
[0029] The process of obtaining modified PVC and the modified PVC of the
present invention has been found to be novel. The prior art available is modified
25 PVC with reduction in chlorine content up to 50-60% by the inventors
themselves. Whereas the process of obtaining modified PVC in the present
invention achieves reduction in chlorine content up to 90% which was found to be
novel and technically advanced as compared to the prior art.
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[0030] Products (Polymers) were characterised by using FT-IR and TGA analysis. FT-IR confirms the structure of polymer with bonding. TGC show thermal behaviour of polymer which is important for working environment for the polymer and it gives information that up to what temperature it can be used.Figure-4 shows TGA analysis and it shows that modified polymer becomes 5 soft or melts near 190°C which is much higher temperature for stability.
[0031] Modified polymer as designed under this present invention, is almost stable as original PVC. Modified polymer is more Valuable product in today’s scenario. In the present invention, a new modified polymer has been developed, which can be used as a substitute of PVC. New modified polymer is having good 10 thermal stability, inertness and very lesser Chlorine (less than 10%) content.
[0032] The following are illustrative examples of the activity of the antimicrobial peptide. It should be understood that the following examples are illustrative only and not limitative of the invention.
Example 1: 15
Cross linking of PVC with amines in organic solvents (Dioxane/ DMF)
[0033] PVC powder was dissolved in dioxane/ DMF at 400C with stirring on a magnetic stirrer to obtain a clear 5 to 50 (w/v) percent solution. Concentrated alcoholic KOH solution was added (5-20%). For getting modified crosslinked and grafted Polymer of PVC, it is first modified by crosslinking of selected 20 bifunctional amines like ethanolamine and di-ethytriamine in dioxane and DMF solvent in the presence of basic medium. The amine (90-95% in aqueous solution) was added in small portions with vigorous stirring and the temperature was raised step wise to (80±5)0C, (100±5)0C and (120±5)0C in different experiments. Bifunctional amine concentration was varied from 20% to 100 % (v/v).Stirring 25 was continued for 3-8 hrs and the crosslinked product was filtered through a sintered glass funnel. The product was washed with hot dioxane/DMF/water and methanol to remove unreacted PVC, dried and weighed at 500C. The experiment
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was repeated by varying the concentration of reactants, temperature and time. Ethylene diamine, ethanolamine and di-ethytriamine were tried for crosslinking. Best product was obtained with diethylenetriamine with less chlorine.
Example 2:
Modification of cross linked PVC 5
[0034] In this method grafting of c-PVC was tried by reaction of maleic anhydride and c-PVC. Weighed quantity (1gm) of c-PVC was taken in the 25 ml DMF in round bottom flask. Reaction mixture was stirred at 60°C for one hr so that polymer becomes soft then weighed quantity of maleic anhydride (20 % to 100% w/w of c-PVC) was added and heated further for 2-4 hrs. For the 10 conversion of anhydric group into carboxylic group 0.1 N sodium hydroxide solution was added and heated further for one hr and finally acidified using 0.1 N HCl solutions to form carboxylic acidic group. The product was filtered , washed and dried in oven at 60°C.
[0035] Reactions of formation of conjugation in PVC in presence of base and 15 probable crosslinked PVC with diethylenetriamine are as-
(PVC) (Conjugated PVC)
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Example 3:
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Characterization by FT-IR of original PVC Polymer and modified polymer
[0036] Original polymer PVC and modified PVC samples (crosslinked with amines) were characterized by FT-IR Spectroscopy. Their FT-IR spectra are shown in fig 1 & 2 respectively. From fig-1 spectrum we observed sharp band at around 700cm-1, which might be characteristic of C-Cl stretching vibration. Bands 5 in the range of 800-1350 cm-1 correspond to C-C stretching vibrations while band around 2950 cm-1 might be due to -C-H stretching vibration. Bands corresponding to deformation or bending vibration of -C-H bond might be at 1430 cm-1. IR spectrum 2 shows the modification done in the original structure of polymer by cross linking of diethyelene triamne. In which major modifications are depicted 10 by presence of new bands and absence of some bands. IR spectrum has absorption bands which are characteristics of specific bonds formed as a result of crosslinking with diethylenetriamine. IR bands around 3310 cm-1 & 1650 cm-1 appear due to secondary N-H stretching vibration and N-H in plane bending vibrations respectively, while band around 1200 cm-1 might be due to C-N 15 stretching vibration in the crosslinked molecule. Extra band around 1600 cm-1 might be due to creation of some C=C bonds as a result of dehydohalogenation reaction in the polymer. Band at 3050 cm-1 corresponds to C-H stretching vibration.
Example 4: 20
TGA/ DTA of PVC and modified Polymer
[0037] Thermal behaviour & stability of the Polymer PVC and crosslinked PVC with various amine samples were characterized by TGA/ DTA analysis. From the thermal analysis it can be interpreted that loss in weight of the crosslinked polymer is much slower as compared to original polymer, about 50% of the 25 crosslinked polymer weight was lost around 400°C while the of original polymer lost 50% of its weight at around 300°C. Although softening point and glass transition temperature were deceased in the modified polymer. Softening point was decreased by about 70°C. Complex structure of the crosslinked polymer is also confirmed by DTG curve. 30
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Example 5:
Modification of PVC with ethylene-diamine
[0038] PVC can be modified by suing ethylene-diamine in the same manner as described below. FT-IR & TGC are shown below for characterization which confirm the development of new polymer with ethylene-diamine. 5
[0039] Bands at 3310 cm-1 and around 1580 cm-1 might be corresponding to secondary N-H stretching & bending in-plane vibrations respectively and this secondary N-H bond would have been formed by elimination of HCl from reaction of NH2 group of ethylenediamine and Cl- atom of polyvinylchloride .Other main bands in the range of 1100-1250 cm-1 might be due to C-N stretching 10 vibrations.

8-20%
We Claim:
1. A process of preparation of an environment friendly substitute for PVC comprising the steps of;
a) dissolving PVC powder in dioxane/ DMF at 400C with stirring on a magnetic stirrer to obtain a clear 5-50 (w/v) % solution; 5
b) adding concentrated alcoholic KOH solution 5-20%;
c) crosslinking 90-95% aqueous solution of selected bifunctional amines such as ethanolamine, ethylene diamine, di-ethytriamine, di-ethytriamine in dioxane,
d) washing in dioxane or DMF solvent in order to remove unreacted 10 PVC followed by drying; and
e) modifying said cross linked PVC as obtained through reacting it with 20 % to 100% w/w of maleic anhydride with respect to said cross-linked PVC in presence of 0.1 N sodium hydroxide solution; and 15
f) final filtering , washing and drying in oven at 60°C.
2. The process as claimed in claim 1, wherein bifunctional amine is diethylenetriamine.
3. The process as claimed in claim 1, wherein said amine was added with vigorous stirring and the temperature was raised step wise to (80±5)ºC, 20 (100±5) ºC and (120±5) ºC.
4. The process as claimed in claim 3, wherein said stirring was continued for 3-8 hrs.
5. The process as claimed in claim 1, wherein said drying was performed in 50ºC. 25
6. The process as claimed in claim 1, wherein 1gm of crosslinked PVC was taken in the 25 ml DMF in round bottom flask prior reacting it with maleic anhydride.
7. The process as claimed in claim 1, wherein the step of modification was performed by stirring reaction mixture at 60°C for 1 hour so that polymer 5 becomes soft, and ready for reaction in said step of modification.