DESC:FIELD
The present disclosure relates to a copolymer and a process for its preparation.
BACKGROUND
Concrete is a composite material consisting of an aggregate and a binder. Typically, concrete compositions contain cement as a binder, which can be supplemented or replaced by a polymeric component. The concrete composition thus prepared is known as polymer concrete.
Polymer concrete can be used in the construction industry where protection from corrosion is desired. Polymer concrete can be used as a partial or complete replacement to ordinary Portland cement and as a sealant for concrete and reinforced concrete structures to prevent the effect of salt water, waste water, and chemicals on these structures.
The advantages of polymer concrete include rapid curing at ambient temperatures, adhesion to most surfaces, long-term durability with respect to freeze and thaw cycles, low permeability to water and aggressive solutions, resistance to chemicals, and resistance to corrosion.
Polysulfide is being used as the polymeric component in a large number of polymer concrete compositions. However, polysulfide is a brittle and crystalline material having poor processability.
It is desired that the polymeric component used as a binder in the polymer concrete compositions possesses good mechanical properties that are amenable to melt or solution processing. Polymer concrete compositions having a broad range of properties can be obtained by incorporating polymeric component having high processability.
Further, the polymer concrete compositions comprise aggregates such as silica, quartz, granite, and limestone; and hence, it is desired that the polymeric component used in these compositions has good compatibility with these aggregates.
Furthermore, it is desired that the polymeric component provides concrete compositions with a broad range of properties that can be varied depending upon the intended use.
Thus, there is felt a need to provide a polymeric component having requisite processability and that the properties of the polymeric component are suitably modified so as to prepare concrete compositions of desired properties.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
It is an object of the present disclosure to provide a polymeric component for preparing polymer concrete.
Another object of the present disclosure is to provide a process for preparing the polymeric component used for preparing polymer concrete.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
A copolymer prepared by reacting reactants comprising sulfur and an olefin compound is disclosed. The olefin compound is at least one selected from the group consisting of divinyl monomers, diallyl monomers, cyclic diolefin monomers, glycidyl ether compounds, and rubber polymers. The amount of the olefin compound is in the range of 5wt% to 50wt% of the reactants.
Typically, the divinyl monomers are selected from the group consisting of divinyl sulfone, divinyl terminated polydimethylsiloxane compounds, vinyl crotonate, and adipic acid divinyl ester.
Typically, the diallyl monomers are selected from the group consisting of diallyl phthalate, diallyl isophthalate, 2,2-bis(allyloxymethyl)-1-butanol, and triallylamine. Typically, the cyclic diolefin monomers are selected from the group consisting of cyclodiolefin, bicyclodiolefin, and polycyclodiolefin.
Typically, the rubber polymers are selected from the group consisting of de-vulcanized crumb rubber, crumb rubber, unvulcanized natural rubber, unvulcanized synthetic rubber, ex-reactor natural rubber, and ex-reactor synthetic rubber.
Typically, the glycidyl ether compounds are selected from the group consisting of bisphenol-A modified epoxy resin (BER), epoxy modified dicyclopentadiene (EDP), and epoxy modified vinylnorbornene (EVN).
A process for the preparation of the copolymer of the present disclosure is also disclosed.
A source of sulfur is melted at a temperature in the range of 150° C to 200° C to obtain molten sulfur. An olefin compound is then added to the molten sulfur to obtain a mixture. The olefin compound is at least one selected from the group consisting of divinyl monomers, diallyl monomers, cyclic diolefin monomers, and rubber polymers. The amount of the olefin compound is taken in the range of 5wt% to 50wt% of the total amount of sulfur and the olefin compound. The mixture is then subjected to polymerization at a temperature in the range of 150° C to 200° C to obtain the copolymer.
Typically, the divinyl monomers used in the process of the present disclosure are selected from the group consisting of divinyl sulfone, divinyl terminated polydimethylsiloxane compounds, vinyl crotonate, and adipic acid divinyl ester.
Typically, the diallyl monomers used in the process of the present disclosure are selected from the group consisting of diallyl phthalate, diallyl isophthalate, 2,2-bis(allyloxymethyl)-1-butanol, and triallylamine. Typically, the cyclic diolefin monomers used in the process of the present disclosure are selected from the group consisting of cyclodiolefin, bicyclodiolefin, and polycyclodiolefin.
Typically, the rubber polymers used in the process of the present disclosure are selected from the group consisting of de-vulcanized crumb rubber, crumb rubber, unvulcanized natural rubber, unvulcanized synthetic rubber, ex-reactor natural rubber, and ex-reactor synthetic rubber.
Typically, the glycidyl ether compounds used in the process of the present disclosure are selected from the group consisting of bisphenol-A modified epoxy resin (BER), epoxy modified dicyclopentadiene (EDP), and epoxy modified vinylnorbornene (EVN).
The copolymer of the present disclosure is suitably used in a concrete composition. Using the concrete composition, concrete articles are suitably prepared which are observed to have desired properties.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The copolymer and the process of the present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 depicts the FT-IR spectra of polysulfide-co-5-DVS (A), divinylsulfone (DVS) (B), and polysulfide homopolymer (C).
Figure 2 depicts the FT-IR spectra of polysulfide-co-5-DV-PDMS (A), a divinyl polydimethylsulfoxide compound (DV-PDMS) (B), and polysulfide homopolymer (C).
Figure 3 depicts FT-IR spectra of polysulfide homopolymer, and the copolymers of the present disclosure. Curve 3(a) depicts an FT-IR spectrum of polysulfide homopolymer; curve 3(b) depicts an FT-IR spectrum of polysulfide-co-5-DVS; curve 3(c) depicts an FT-IR spectrum of polysulfide-co-5-DV-PDMS ; curve 3(d) depicts an FT-IR spectrum of polysulfide-co-5-DVA; curve 3(e) depicts an FT-IR spectrum of polysulfide-co-5-DAP, and curve 3(f) depicts an FT-IR spectrum of polysulfide-co-5-DV-DIAP,
Figures 4a and 4b depict the 13C-NMR spectra of DVS, and polysulfide-co-5-DVS respectively.
Figure 5 depicts the UV-visible light absorption spectra of polysulfide homopolymer (1), polysulfide-co-5-DVS (2), polysulfide-co-5-DV-PDMS (3), polysulfide-co-25-DVS (4), and polysulfide-co-25-DV-PDMS (5).
Figure 6a depicts DSC spectra of polysulfide homopolymer (i), polysulfide-co-5-DVS (ii), polysulfide-co-10-DVS (iii), and polysulfide-co-20-DVS (iv).
Figure 6b depicts DSC spectra of polysulfide homopolymer (i), polysulfide-co-5-DV-PDMS (ii), polysulfide-co-10-DV-PDMS (iii), and polysulfide-co-20-DV-PDMS (iv).
Figure 6c depicts DSC spectra of a polysulfide copolymer prepared using 5wt% with various monomers; (i) shows the DSC spectrum of polysulfide-co-5-DAP; (ii) shows the DSC spectrum of polysulfide-co-5-VC; (iii) shows the DSC spectrum of polysulfide-co-5-DIAP; and (iv) shows the DSC spectrum of polysulfide-co-5-DVA.
Figures 7A and 7B depict thermogravimetric analysis (TGA) of polysulfide-co-5-DVS and polysulfide-co-25-DVS.
Figures 7C and 7D depict TGA of polysulfide-co-5-DV-PDMS and polysulfide-co-25-DV-PDMS.
Figures 8 depicts photographs (A, B, C and D) of the concrete articles prepared using binder, and silica in the ratio of 2:1 on mass basis; and wherein the binder is a mixture of the copolymers of the present disclosure and cement. A photograph of a concrete article prepared using a mixture of 90% polysulfide and 10% Portland cement as the binder is shown in Figure 8A; using 90% polysulfide-co-20-DVS with 10% Portland cement as the binder is shown in Figure 8B; using 80% polysulfide-co-20-DVS with 20% Portland cement is shown in Figure 8C; and using 70% polysulfide-co-20-DVS with 30% Portland cement is shown in Figure 8D.
DETAILED DESCRIPTION
Polysulfide, used for the preparation of polymer concrete, is a brittle, and crystalline material having poor processability. The problem of brittleness, and poor processability of polysulfide is solved in the present disclosure by copolymerizing sulfur, and an olefin compound. Each of the olefin compounds is capable of reacting with more than two monomers which is needed for preparing a partially cross-linked polymer. The presence of such an olefin compound provides a site for the partial cross-linking of the polymer chains. This partial crosslinking provides better processability to polysulfide.
In accordance with one aspect of the present disclosure, a copolymer prepared by reacting reactants comprising sulfur, and an olefin compound is disclosed. The olefin compound is at least one selected from the group consisting of divinyl monomers, diallyl monomers, cyclic diolefin monomers, glycidyl ether compounds, and rubber polymers.
The olefin compound comprises a diene moiety in its structure, and this diene moiety enables it to react with more than two monomers. The olefin compound has a functionality of four, and is capable of reacting with a maximum of four monomers. The ability of the olefin compound to react with four monomers enables it to be a part of the polymer backbone (via chain propagation), and also enables it to crosslink the polysulfide.
In accordance with the embodiments of the present disclosure, the divinyl monomers are selected from the group consisting of divinyl sulfone (DVS), divinyl terminated polydimethylsiloxane compounds (DVPDMS), vinyl crotonate (VC), and adipic acid divinyl ester (DVA). In a particular embodiment, the olefin compound is divinyl sulfone (DVS). In another specific embodiment, the olefin compound is divinyl terminated polydimethylsiloxane compound (DV-PDMS).
In accordance with the embodiments of the present disclosure, the diallyl monomers are selected from the group consisting of diallyl phthalate (DAP), diallyl isophthalate (DAIP), 2, 2-bis(allyloxymethyl)-1-butanol, and triallylamine. In a specific embodiment, the olefin compound is selected as diallyl phthalate (DAP).
In accordance with the embodiments of the present disclosure, the cyclic diolefin monomers are selected from the group consisting of cyclodiolefin, bicyclodiolefin, and polycyclodiolefin.
In accordance with the embodiments of the present disclosure, the rubber polymers are selected from the group consisting of de-vulcanized crumb rubber, crumb rubber, unvulcanized natural rubber, unvulcanized synthetic rubber, ex-reactor natural rubber, and ex-reactor synthetic rubber.
In accordance with the embodiments of the present disclosure, the glycidyl ether compounds are selected from the group consisting of bisphenol-A modified epoxy resin (BER), epoxy modified dicyclopentadiene (EDP), and epoxy modified vinylnorbornene (EVN).
The amount of the olefin compound in the copolymer of the present disclosure is in the range of 5wt% to 50wt% of the reactants.
The physical properties of the copolymer of the present disclosure depend on the degree of cross-linking between the polymer chains. The degree of cross-linking, in turn, depends on the proportion of the amount of the olefin compound, and the amount of sulfur. A high amount of the olefin compound provides a high degree of cross-linking to the copolymer.
Accordingly, the physical properties of the copolymer of the present disclosure can be varied by varying the proportion of the amount of the olefin compound, and the amount of sulfur.
Physical properties of the copolymer such as processability also depend on the nature of the olefin compound used. Therefore, copolymers with a wide range of desired physical properties can be obtained by using various aforementioned olefin compounds.
In accordance with another aspect of the present invention, there is provided a process for preparing the copolymer of the present disclosure. The process involves the following steps.
A source of sulfur is melted at a temperature in the range from 150° C to 200° C to obtain molten sulfur. An olefin compound is added to the molten sulfur to obtain a mixture. The olefin compound is at least one selected from the group consisting of divinyl monomers, diallyl monomers, cyclic diolefin monomers, glycidyl ether compounds, and rubber polymers. The amount of the olefin compound in the mixture ranges from 5wt% to 50wt% of the total amount of sulfur, and the olefin compound.
The divinyl monomers used in the process of the present disclosure are selected from the group consisting of divinyl sulfone (DVS), divinyl terminated polydimethylsiloxane compounds (DVPDMS), vinyl crotonate (VC), and adipic acid divinyl ester (DVA). In a particular embodiment, the olefin compound is divinyl sulfone (DVS). In another specific embodiment, the olefin compound is divinyl terminated polydimethylsiloxane compound (DV-PDMS).
The diallyl monomers used in the process of the present disclosure are selected from the group consisting of diallyl phthalate (DAP), diallyl isophthalate (DAIP), 2,2-bis(allyloxymethyl)-1-butanol, and triallylamine. In a specific embodiment, the olefin compound is selected as diallyl phthalate (DAP).
The cyclic diolefin monomers used in the process of the present disclosure are selected from the group consisting of cyclodiolefin, bicyclodiolefin, and polycyclodiolefin.
The rubber polymers used in the process of the present disclosure are selected from the group consisting of de-vulcanized crumb rubber, crumb rubber, unvulcanized natural rubber, unvulcanized synthetic rubber, ex-reactor natural rubber, and ex-reactor synthetic rubber.
The glycidyl ether compounds used in the process of the present disclosure are selected from the group consisting of bisphenol-A modified epoxy resin (BER), epoxy modified dicyclopentadiene (EDP), and epoxy modified vinylnorbornene (EVN).
The mixture of molten sulfur and the olefin compound is allowed to polymerize at a temperature in the range from 150° C to 200° C for a time period in the range of 50 minutes to 500 minutes to obtain the copolymer of the present disclosure.
The copolymer of the present disclosure is used in a concrete composition wherein the copolymer of the present disclosure acts as the binder. The concrete composition additionally comprises at least one aggregate selected from the group consisting of fumed silica, silica, sand, stones, and brickbats In accordance with one embodiment of the present disclosure, the aggregate in the concrete composition is silica.
The ratio of the amount of the binder and the amount of the aggregate in the concrete composition is in the range from 1:1 to 1:3, preferably 1:2.
In accordance with one embodiment of the present disclosure, the concrete composition comprises at least one additional binder such as the binder comprises a mixture of the copolymer of the present disclosure, and at least one additional binder. In a specific embodiment, the additional binder is Portland cement.
The ratio of the amount of the copolymer and the amount of Portland cement is in the range of 1:1 to 1:10.
A concrete article is prepared using the concrete composition comprising the copolymer of the present disclosure. The process for preparing the concrete article involves the following steps.
The copolymer of the present disclosure is maintained at a temperature in the range from 150° C to 200° C, and at least one aggregate is added to obtain a mixture. The mixture is stirred while being heated at a temperature in the range from 150° C to 200° C to obtain a homogeneous mixture. The homogeneous mixture is received in a mold, and is cured at a temperature in the range from 150? C to 200? C for a time period ranging from 15 minutes to 300 minutes, and further cooled to obtain the concrete article.
In accordance with one embodiment, the step of curing is carried out for 30 minutes.
In accordance with one embodiment, the process of preparing the concrete article involves the addition of at least one dye to the mixture of first step to obtain a colored concrete article.
In accordance with one embodiment of the present disclosure, the concrete article is prepared by using an aggregate, and a binder containing a mixture of the copolymer of the present disclosure, and cement. The concrete articles prepared using the concrete composition comprising the copolymer of the present disclosure as the binder, have better mechanical properties such as compressive strength, flexural strength, and tensile strength, and better surface properties as compared to concrete articles prepared using ordinary Portland cement.
Polymerization of sulfur to form polysulfide takes place through a free radical intermediate at a temperature in the range from 175° C to 190° C. The growing polysulfide chain is terminated by the reaction of the free radical intermediate with a chain termination agent. The reaction is known as quenching of the free radical intermediate.
Stabilization of the free radical intermediate prevents the quenching, and allows growth of the polysulfide chain, resulting in the formation of a high molecular weight polymer.
In the present disclosure, the olefin compound stabilizes the free radical intermediate during the polymerization process.
The present disclosure is further described in the light of the following laboratory experiments which are set forth for illustration purpose only, and not to be construed for limiting the scope of the disclosure. The following experiments can be scaled up to industrial/commercial scale, and the results obtained can be extrapolated to industrial scale.
EXPERIMENTS
Experiments 1 to 19
Copolymers according to the present disclosure were prepared using sulfur and the olefin compounds selected from DVS, DV-PDMS, DVA, VC, DAP, DAIP, BER, EDP and EVN. Sulfur is melted at 160° C to obtain molten sulfur. The olefin compound was added to the molten sulfur and they were copolymerized to obtain various copolymers. Some olefin compounds used to prepare the copolymer of the present disclosure are shown in Table 1.
Table 1: Structures of some olefin compounds used for preparation of the copolymer of the present disclosure.
S. No. Olefin Compound Code Structure
1 Divinyl Sulfone DVS
2 Divinyl terminated polydimethylsiloxane DV-PDMS
3 Adipic acid divinyl ester DVA
4 Vinyl crotonate VC
5 Diallyl Phthalate DAP
6 Diallyl Isophthalate DAIP

The Ratio of sulfur: olefin compounds and the resultant copolymers prepared are as mentioned in Table 2.

Table 2: Copolymers prepared by varying the amounts of sulfur and olefin compounds.
Exp Olefin compound Ratio of sulfur: olefin compound (w/w%) Temperature

(° C) Molar amounts of sulfur and the olefin compounds (mmols) Copolymer Code
Exp. 1 Divinyl Sulfone (DVS) 95:5 185 74.2 (Sulfur)
8.46 (DVS) Polysulfide-co-5-DVS
Exp. 2 Divinyl terminated polydimethylsiloxane (DV-PDMS) 95:5 185 74.2 (Sulfur)
5.3 (DV-PDMS) Polysulfide-co-5-DV-PDMS
Exp. 3 Adipic acid divinyl ester (DVA) 95:5 187 74.2 (Sulfur)
5.04 (DVA) Polysulfide-co-5-DVA
Exp. 4 Vinyl crotonate (VC) 95:5 185 74.2 (Sulfur)
8.92 (VC) Polysulfide-co-5-VC
Exp. 5 Diallyl Phthalate (DAP) 95:5 186 74.2 (Sulfur)
4.06 (DAP) Polysulfide-co-5-DAP
Exp. 6 Diallyl Isophthalate (DAIP) 95:5 186 74.2 (Sulfur)
4.06 (DAIP) Polysulfide-co-5-DAIP
Exp. 7 Divinyl Sulfone (DVS) 90:10 189 70.3 (Sulfur)
16.9 (DVS) Polysulfide-co-10-DVS
Exp. 8 Divinyl terminated polydimethylsiloxane (DV-PDMS) 90:10 188 70.3 (Sulfur)
10.7 (DV-PDMS) Polysulfide-co-10-DV-PDMS
Exp. 9 Divinyl Sulfone (DVS) 80:20 187 62.5 (Sulfur)
33.8 (DVS) Polysulfide-co-20-DVS
Exp. 10 Divinyl terminated polydimethylsiloxane (DV-PDMS) 80:20 187 62.5 (Sulfur)
21.5 (DV-PDMS) Polysulfide-co-20-DV-PDMS
Exp. 11 Divinyl Sulfone (DVS) 75:25 185 58.6 (Sulfur)
42.3 (DVS) Polysulfide-co-25-DVS
Exp. 12 Divinyl terminated polydimethylsiloxane (DV-PDMS) 75:25 186 58.6 (Sulfur)
26.9 (DV-PDMS) Polysulfide-co-25-DV-PDMS
Exp. 13 Divinyl Sulfone (DVS) 60:40 185 46.8 (Sulfur)
67.7 (DVS) Polysulfide-co-40-DVS
Exp. 14 Divinyl terminated polydimethylsiloxane (DV-PDMS) 60:40 189 46.8 (Sulfur)
43.01 (DV-PDMS) Polysulfide-co-40-DV-PDMS
Exp. 15 Divinyl Sulfone (DVS) 50:50 187 39.06 (Sulfur)
84.6 (DVS) Polysulfide-co-50-DVS
Exp. 16 Divinyl terminated polydimethylsiloxane (DV-PDMS) 50:50 185 39.06 (Sulfur)
53.5 (DV-PDMS) Polysulfide-co-50-DV-PDMS
Exp. 17 Bisphenol A modified Epoxy resin (BER) 95:5 189 74.2 (Sulfur)
0.05 (BER) Polysulfide-co-5-BER
Exp. 18 Epoxy modified dicyclopentadiene (EDP) 95:5 152 74.2 (Sulfur)
2.9 (EDP) Polysulfide-co-5-EDP
Exp. 19 Epoxy modified vinylnorbornene (EVN) 95:5 150 74.2 (Sulfur)
3.24 (EVN) Polysulfide-co-5-EVN
The copolymer Polysulfide-co-20-DVS of Experiment 9 was analyzed by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR). Also, polysulfide homopolymer and the monomer DVS were analyzed using FT-IR and NMR.
In Figure 1, A shows the FT-IR spectrum for Polysulfide-co-20-DVS; whereas, B, and C show the FT-IR spectra for DVS, and polysulfide homopolymer respectively.
Figure 4a shows the 13C-NMR spectrum for DVS, and Figure 4b shows the 13C-NMR spectrum for Polysulfide-co-20-DVS. The disappearance of the resonance peaks for the olefinic carbon atoms of DVS from ? 129.7, and 137.0 ppm, and an upfield shift of the resonance to ? 59.6, and 26.9 ppm in 13C-NMR spectrum Polysulfide-co-20-DVS indicates the formation of the desired copolymer.
UV-Visible absorption spectra of polysulfide homopolymer, Polysulfide-co-5-DVS, Polysulfide-co-25-DVS, Polysulfide-co-5-DV-PDMS and polysulfide-co-25-DV-PDMS formed were recorded in a (0.2g/cc) solution in 1, 2-dichlorobenzene. The results were as seen in Figure 5. In Figure 5, 1 shows the UV-Visible absorption spectrum for polysulfide homopolymer; 2, and 3 show the UV-Visible absorption spectra of Polysulfide-co-5-DVS, and Polysulfide-co-5-DV-PDMS respectively; and 4, and 5 show the UV-Visible absorption spectra of polysulfide-co-25-DVS and polysulfide-co-25-DV-PDMS respectively. The absorption maxima (?max) of all the polymeric compositions were observed at 320 nm owing to the polysulfide chains (–S–Sx–S-). It is observed that the ?max values for the polysulfide homopolymer and the copolymers formed are close to each other.
The copolymer Polysulfide-co-20-DV-PDMS of Experiment 10 was analyzed by using FT-IR, NMR and UV. In Figure 2, A shows the FT-IR spectrum for Polysulfide-co-20-DV-PDMS; whereas, B, and C shows the FT-IR spectra for DV-PDMS, and polysulfide homopolymer respectively. In Figure 3, (a) shows the FT-IR spectrum for polysulfide homopolymer. Figure 3 (b), (c), (d), (e), and (f) show the FT-IR spectra of the Polysulfide-co-5-DVS, Polysulfide-co-5-DV-PDMS, Polysulfide-co-5-DVA, Polysulfide-co-5-DAP, and Polysulfide-co-5- DIAP respectively, prepared in Experiments 1, 2, 3, 5, and 6. An absorption band at 1080 cm-1 in the FTIR spectra of the copolymers of the present disclosure indicated the presence of C-S bond, thereby indicating the formation of desired copolymers. The absorption band at 1080 cm-1 is marked in Figure 3 by a dotted line.
Physical properties of the copolymers such as crystallinity and thermal stability were determined.
Crystallinity of the copolymers
Crystallinity of the copolymers was evaluated using differential scanning calorimetry (DSC). DSC of Polysulfide-co-5-DVS, Polysulfide-co-10-DVS and Polysulfide-co-20-DVS are shown in Figure 6a (ii), (iii) and (iv) respectively. DSC of Polysulfide-co-5-DV-PDMS, Polysulfide-co-10-DV-PDMS and Polysulfide-co-20-DV-PDMS is shown in Figure 6b (ii), (iii) and (iv) respectively. DSC of polysulfide homopolymer is also provided in Figures 6a (i), and 6b (i) for comparative analysis.
DSC of the polysulfide homopolymer shows two characteristic melting phase transitions (Tm) originating from the orthorhombic phase, and the monoclinic phase at 110° C, and 124° C, respectively.
A decrease in the amplitude of these characteristic melting transitions (Tm) with increasing amount of DVS in polysulfide-co-DVS suggest a decrease in the crystallinity of the polymeric compositions with an increasing amount of DVS.
Polysulfide-co-20-DVS showed absence of both the characteristic melting transitions (Tm) which indicates that polysulfide-co-20-DVS is non-crystalline in nature.
Increasing the amount of the DV-PDMS compound in polysulfide-co-DV-PDMS led to the disappearance of the melting transition (Tm) related to the monoclinic phase. This change in the melting transition (Tm) indicated a partial crystalline nature of polysulfide-co-20-DV-PDMS.
These results are corroborated by the UV spectra shown in Figure 5. A longer wavelength absorption band (low energy band) at 420 nm was observed in the absorption spectrum of Polysulfide-co-20-DVS (spectrum 4), which indicates lack of crystallinity of the Polysulfide-co-20-DVS copolymer. Absence of such an absorption band in the absorption spectrum for polysulfide-co-20-DV-PDMS (spectrum 5) indicates some crystalline nature of polysulfide-co-20-DVPDMS.
Figure 6c shows the DSC of Polysulfide-co-5-DAP, Polysulfide-co-5-VC, Polysulfide-co-5-DIAP, and Polysulfide-co-5-DVA. In Figure 6c, (i) shows the DSC spectrum of polysulfide-co-5-DAP; (ii) shows the DSC spectrum of polysulfide-co-5-VC; (iii) shows the DSC spectrum of polysulfide-co-5-DIAP, and (iv) shows the DSC spectrum of polysulfide-co-5-DVA. The melting phase transitions (Tm) originating from the orthorhombic phase, and the monoclinic phase are observed at 103° C, and 115° C, respectively.
The DSC spectra showed that Polysulfide-co-5-DAP and Polysulfide-co-5-DVA predominantly contain the crystalline copolymer related to monoclinic phase, whereas, Polysulfide-co-5-VC, and Polysulfide-co-5-DAIP showed crystalline copolymers related to both orthorhombic phase as well as monoclinic phase in significant amounts. The crystalline copolymer containing monoclinic phase is denser as compared to the crystalline copolymer containing the orthorhombic phase, which in turn is denser than the copolymer containing the amorphous phase.
Thermal stability of copolymers
The thermogravimetric analysis (TGA) of polysulfide homopolymer, Polysulfide-co-5-DVS, Polysulfide-co-25-DVS, Polysulfide-co-5-DV-PDMS, and Polysulfide-co-25-DV-PDMS are shown in Figures 7(A), 7(B), 7(C) and 7(D). Figures 7(A) and 7(B) show the TGA of Polysulfide-co-5-DVS and Polysulfide-co-25-DVS, respectively. Figures 7(C) and 7(D) show the TGA of the Polysulfide-co-5-DV-PDMS and Polysulfide-co-25-DV-PDMS, respectively. The copolymers showed weight loss in the range from 225° C to 237° C. The data is provided in Table 3.
Table 3: Thermal stability data of copolymers
Sample W120° C (%) W300° C (%) T10% (?C)
Polysulfide (homopolymer) 91 17 200
Polysulfide-co-5-DVS 98 37 225
Polysulfide-co-25-DVS 99.25 51 227
Polysulfide-co-5-DV-PDMS 98.75 59 230
Polysulfide-co-25-DV-PDMS 99.25 62 237
W120° C – weight loss percentage when heated to 120° C; W300° C – weight loss percentage when heated to 300° C; T10% - Temperature at which 10% sample degrades.
The W120° C and T10% values of the copolymers were found to be higher than that for the polysulfide homopolymer. Thus, the copolymers of the present disclosure were found to have higher thermal stability as compared to polysulfide.
Experiment 20
Four concrete articles were prepared using a binder and silica in the ratio of 1:2 on mass basis. The binders used were:
1. a mixture of 90% polysulfide and 10% Portland cement;
2. a mixture of 90% polysulfide-co-20-DVS and 10% Portland cement;
3. a mixture of 80% polysulfide-co-20-DVS and 20% Portland cement; and
4. a mixture of 70% polysulfide-co-20-DVS and 30% Portland cement.
Concrete articles were prepared using these binders. The photographs of the concrete articles prepared using the mixture of 90% polysulfide and 10% Portland cement is shown in Figure 8A; using 90% polysulfide-co-20-DVS with 10% Portland cement is shown in Figure 8B; using 80% polysulfide-co-20-DVS with 20% Portland cement is shown in Figure 8C; and using 70% polysulfide-co-20-DVS with 30% Portland cement is shown in Figure 8D.
It is clearly seen that the concrete articles as shown in Figures 8B, 8C, and 8D have better surface finish than the concrete article seen in Figure 8A.
Experiment 21
Concrete compositions were prepared using sand (as the aggregate), and the copolymers prepared in Experiments 1 to 19 as binder in the ratio of 2:1 (aggregate:binder). The physical properties of the copolymers used varied depending upon the ratio of the amount of sulfur and the amount of the olefin compound. The concrete compositions thus prepared were used for the preparation of molded concrete articles.
Thermo-mechanical properties
The concrete articles prepared using the copolymers of the present disclosure showed superior thermo-mechanical properties as compared to the concrete articles prepared using polysulfide.
Table 4 shows a comparison of the mechanical properties of concrete articles prepared by a polymer concrete comprising Polysulfide-co-5-DVA (prepared in Experiment 3), a polymer concrete comprising Polysulfide-co-5-BER (prepared in Experiment 17), and ordinary cement concrete.
Table 4: Comparison of the mechanical properties of concrete articles
Properties Unit Cement Concrete (after 28 days) Polysulfide-co-5-BER based Concrete (After 7 days) (epoxy based system) Polysulfide-co-5-DVA based Concrete (After 7 days) (vinylic ester based system)
Compressive Strength MPa 25-30 34 37
Tensile Strength MPa 1-3 3 4
Flexural Strength MPa 4-6 8 10
From Table 4, it is evident that the concrete articles prepared using concrete comprising Polysulfide-co-5-DVA and Polysulfide-co-5-BER exhibit superior mechanical properties of compressive strength, tensile strength, and flexural strength as compared to ordinary cement concrete articles.
Further, the concrete articles of the present disclosure can be used for preparation of a wide range of construction products such as paving bricks, I-blocks, curb stones, tiles, and the like.
Experiment 22
Blue and black dyes were mixed with concrete compositions comprising Polysulfide-co-5-DVA as prepared in Experiment 21 and colored concrete articles were prepared using the colored concrete compositions. The obtained colored concrete articles showed good dispersibility of the dyes in the concrete articles.
TECHNICAL ADVANCES AND ECONOMICAL SIGNIFICANCE
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a copolymer that:
? provides a polymeric component for preparing polymer concrete; and
? is a substitute to polysulfide homopolymer based polymer concrete.
The foregoing description of the specific embodiments so fully reveals the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations, and modifications should, and are intended to be comprehended within the meaning, and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description, and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit, and scope of the embodiments as described herein.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations, and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components, and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These, and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure, and not as a limitation.
,CLAIMS:1. A copolymer prepared by reacting reactants comprising sulfur, and an olefin compound, said olefin compound being at least one selected from the group consisting of divinyl monomers, diallyl monomers, cyclic diolefin monomers, glycidyl ether compounds and rubber polymers, wherein the amount of said olefin compound is in the range of 5wt% to 50wt% of said reactants.
2. The copolymer as claimed in claim 1, wherein the divinyl monomers are selected from the group consisting of divinyl sulfone, divinyl terminated polydimethylsiloxane compounds, vinyl crotonate, and adipic acid divinyl ester.
3. The copolymer as claimed in claim 1, wherein the diallyl monomers are selected from the group consisting of diallyl phthalate, diallyl isophthalate, 2, 2-bis(allyloxymethyl)-1-butanol, and triallylamine.
4. The copolymer as claimed in claim 1, wherein the cyclic diolefin monomers are selected from the group consisting of cyclodiolefin, bicyclodiolefin, and polycyclodiolefin.
5. The copolymer as claimed in claim 1, wherein the rubber polymers are selected from the group consisting of de-vulcanized crumb rubber, crumb rubber, unvulcanized natural rubber, unvulcanized synthetic rubber, ex-reactor natural rubber, and ex-reactor synthetic rubber.
6. The copolymer as claimed in claim 1, wherein the glycidyl ether compounds are selected from the group consisting of bisphenol-A modified epoxy, epoxy modified dicyclopentadiene and epoxy modified vinylnorbornene.
7. A process for the preparation of a copolymer of sulfur and an olefin compound, said process comprising the following steps:
i) melting a source of sulfur at a temperature in the range of 150° C to 200° C to obtain molten sulfur;
ii) adding an olefin compound to said molten sulfur to obtain a mixture, wherein the amount of said olefin compound is in the range of 5wt% to 50wt% of the total amount of sulfur, and said olefin compound being at least one selected from the group consisting of divinyl monomers, diallyl monomers, cyclic diolefin monomers, glycidyl ether compounds and rubber polymers; and
iii) allowing said mixture to polymerize at a temperature in the range of 150° C to 200° C to obtain said copolymer.
8. The process as claimed in claim 7, wherein the divinyl monomers are selected from the group consisting of divinyl sulfone, divinyl terminated polydimethylsiloxane compounds, vinyl crotonate, and adipic acid divinyl ester.
9. The process as claimed in claim 7, wherein the diallyl monomers are selected from the group consisting of diallyl phthalate, diallyl isophthalate, 2, 2-bis(allyloxymethyl)-1-butanol, and triallylamine.
10. The process as claimed in claim 7, wherein the cyclic diolefin monomers are selected from the group consisting of cyclodiolefin, bicyclodiolefin, and polycyclodiolefin.
11. The process as claimed in claim 7, wherein the rubber polymers are selected from the group consisting of de-vulcanized crumb rubber, crumb rubber, unvulcanized natural rubber, unvulcanized synthetic rubber, ex-reactor natural rubber, and ex-reactor synthetic rubber.
12. The process as claimed in claim 7, wherein the glycidyl ether compounds are selected from the group consisting of bisphenol-A modified epoxy, epoxy modified dicyclopentadiene, and epoxy modified vinylnorbornene.
13. A concrete composition comprising the copolymer as claimed in claim 1.
14. A concrete article prepared using the concrete composition as claimed in claim 13.