ELASTOMERIC COPOLYMERS WITH A HIGH SULFUR CONTENT AND PROCESS FOR THEIR PREPARATION

Abstract

Elastomeric copolymer with a high sulfur content, comprising sulfur in a quantity higher than or equal to 40% by weight, preferably ranging from 55% by weight to 90% by weight, with respect to the total weight of said elastomeric copolymer, and at least one monomer having general formula (I): CH.sub.2═CH—(CH.sub.2).sub.y-(X).sub.n-(X).sub.m-(CH.sub.2).sub.x—CH═CH.sub.2 (I) wherein: X represents a sulfur atom, a selenium atom, a tellurium atom, preferably a sulfur atom, a selenium atom; y and x, equal to or different from one another, are a whole number ranging from 0 to 4; n and m, equal to or different from one another, are a whole number ranging from 0 to 3, at least one of n and m being equal to 1; said monomer being present in a quantity lower than or equal to 60% by weight, preferably ranging from 10% by weight to 45% by weight, with respect to the total weight of said elastomeric copolymer; provided that, in the case wherein in said general formula (I) X is sulfur, y and x are 1, at least one of n and m must be different from 1 and the sum of n+m must be different from 1. Said elastomeric copolymer with a high sulfur content can be advantageously used in a great many applications such as, for example, thermal insulation, conveyor

Claims

1. Elastomeric copolymer with a high sulfur content, comprising sulfur in a quantity higher than or equal to 40% by weight with respect to the total weight of said elastomeric copolymer, and at least one monomer having general formula (I):
CH.sub.2═CH—(CH.sub.2).sub.y-(X).sub.n-(X).sub.m-(CH.sub.2).sub.x—CH═CH.sub.2   (I) wherein: X represents a sulfur atom, a selenium atom, a tellurium atom; y and x, equal to or different from one another, are a whole number ranging from 0 to 4; n and m, equal to or different from one another, are a whole number ranging from 0 to 3, at least one of n and m being equal to 1; said monomer being present in a quantity lower than or equal to 60% by weight with respect to the total weight of said elastomeric copolymer; provided that, in the case wherein said general formula (I) X is sulfur, y and x are 1, at least one of n and m must be different from 1 and the sum of n+m must be different from 1.

2. Elastomeric copolymer with a high sulfur content according to claim 1, wherein said monomer having general formula (I) is selected from diallyl diselenide, garlic essential oil, divinyl disulphide, or mixtures thereof.

3. Elastomeric copolymer with a high sulfur content according to claim 1, wherein said elastomeric copolymer with a high sulfur content comprises sulfur in a quantity equal to 70% by weight with respect to the total weight of said elastomeric copolymer and at least one monomer having general formula (Ia):
CH.sub.2═CH—(CH.sub.2).sub.y-(X).sub.n-(X).sub.m-(CH.sub.2).sub.x—CH═CH.sub.2   (Ia) wherein: X represents a selenium atom; y is 1; x is 1; n is 1; and m is 1, and wherein said monomer being present in a quantity equal to 30% by weight with respect to the total weight of said elastomeric copolymer.

4. Elastomeric copolymer with a high sulfur content according to claim 1, wherein said elastomeric copolymer with a high sulfur content comprises sulfur in a quantity equal to 70% by weight with respect to the total weight of said elastomeric copolymer and a mixture of monomers having general formula (Ib):
CH.sub.2═CH—(CH.sub.2).sub.y-(X).sub.n-(X).sub.m-(CH.sub.2).sub.x—CH═CH.sub.2   (Ib) wherein: X represents a sulfur atom; y is 1; x is 1; n is 0 or 1; and m is 1 or 2, and wherein said mixture of monomers being present in a quantity equal to 30% by weight with respect to the total weight of said elastomeric copolymer.

5. Elastomeric copolymer with a high sulfur content according to claim 1, wherein said elastomeric copolymer with a high sulfur content comprises sulfur in a quantity equal to 80% by weight with respect to the total weight of said elastomeric copolymer and at least one monomer having general formula (Ic):
CH.sub.2═CH—(CH.sub.2).sub.y-(X).sub.n-(X).sub.m-(CH.sub.2).sub.x—CH═CH.sub.2   (Ic) wherein: X represents a sulfur atom; y is 0; x is 0; n is 1; and m is 1, and wherein said monomer being present in a quantity equal to 20% by weight with respect to the total weight of said elastomeric copolymer.

6. Elastomeric copolymer with a high sulfur content according to claim 1, wherein said elastomeric copolymer with a high sulfur content comprises sulfur in a quantity equal to 70% by weight with respect to the total weight of said elastomeric copolymer and at least one monomer having general formula (Ic):
CH.sub.2═CH—(CH.sub.2).sub.y-(X).sub.n-(X).sub.m-(CH.sub.2).sub.x—CH═CH.sub.2   (Ic) wherein: X represents a sulfur atom; y is 0; x is 0; n is 1; and m is 1, and wherein said monomer being present in a quantity equal to 30% by weight with respect to the total weight of said elastomeric copolymer.

7. Elastomeric copolymer with a high sulfur content according to claim 1, wherein said elastomeric copolymer with a high sulfur content has a glass transition temperature (T.sub.g) higher than or equal to −20° C.

8. Elastomeric copolymer with a high sulfur content according to claim 1, wherein said elastomeric copolymer with a high sulfur content has an elongation at break higher than or equal to 55%.

9. Process for the preparation of an elastomeric copolymer with a high sulfur content comprising: (i) melting the sulfur at a temperature ranging from 110° C. to 190° C. for a time ranging from 1 minute to 15 minutes obtaining sulfur in liquid form; (ii) reacting the sulfur in liquid form obtained in stage (i) with at least one monomer having general formula (I) at a temperature ranging from 110° C. to 190° C. for a time ranging from 1 minute to 15 minutes obtaining a liquid pre-polymer; and (iii) pouring the liquid pre-polymer obtained in stage (ii) into a mould and maintaining said mould at a temperature ranging from 100° C. to 150° C. for a time ranging from 1 hour to 20 hours obtaining an elastomeric copolymer with a high sulfur content.

10. Process for the preparation of a thermoplastic copolymer with a high sulfur content according to claim 9, wherein the sulfur used in said stage (i) is elemental sulfur.

11. Use of an elastomeric copolymer with a high sulfur content according to claim 1, in thermal insulation, conveyor belts, transmission belts, flexible hoses, or elastomeric compositions for tyres.

12. Elastomeric copolymer with a high sulfur content according to claim 1, wherein the sulfur is present from 55% by weight to 90% by weight.

13. Elastomeric copolymer with a high sulfur content according to claim 1, wherein X represents a sulfur atom.

14. Elastomeric copolymer with a high sulfur content according to claim 1, wherein said monomer is present from 10% by weight to 45% by weight.

15. Elastomeric copolymer with a high sulfur content according to claim 1, wherein the T.sub.g is from 18° C. to 10° C.

16. Process for the preparation of a thermoplastic copolymer with a high sulfur content according to claim 9, wherein the sulfur is melted at a temperature from 120° C. to 170° C., wherein the sulfur in liquid form is reacted at a temperature ranging from 120° C. to 170° C. for a time ranging from 2 minutes to 10 minutes, and wherein the liquid pre-polymer is poured and said mould is maintained at a temperature ranging from ranging from 110° C. to 130° C. for a time ranging from 2 hours to 15 hours.

Description

EXAMPLES

Analysis and Characterization Methodologies

[0054] The analysis and characterization methodologies below reported have been used.

Thermal Analysis (DSC)

[0055] The DSC (Differential Scanning calorimetry) thermal analysis, in order to determine the glass transition temperature (T.sub.g) of the copolymers obtained, was carried out by means of a Perkin Elmer Pyris differential scanning calorimeter, using the following thermal programme:

cooling from ambient temperature (T=25° C.) to −60° C. at a rate of −5° C./minute;
heating from −60° C. to +150° C. at a rate of +10° C./minute (first scan);
cooling from +150° C. to −60° C. at a rate of −5° C./minute;
heating from −60° C. to +150° C. at a rate of +10° C./minute (second scan); working under a nitrogen (N.sub.2) stream at 70 ml/minute.

Example 1 (Invention)

Synthesis of Elastomeric Copolymer With Sulfur (70% by Weight) and Diallyl Diselenide (30% by Weight)

[0056] 7 g of pure sulfur [elemental sulfur in the orthorhombic crystalline form (S.sub.8) of Sigma-Aldrich] was charged into a 60 ml glass autoclave equipped with a magnetic stirrer: the autoclave was heated to 160° C. and maintained at said temperature for 10 minutes, thus obtaining the melting of the sulfur, which becomes a yellow liquid. 3 g of liquid diallyl diselenide (Sigma-Aldrich) was then added, drop by drop, to said liquid: the whole was maintained, under stiffing, at 160° C., for 3 minutes, obtaining a solution which remains still fluid and takes on an intense red colour. The fluid solution thus obtained was poured into a Teflon mould that was closed and heated to 120° C. in an oven: said fluid solution was maintained at said temperature for 12 hours, obtaining an elastomeric copolymer black in colour and with translucent appearance.

[0057] Said elastomeric copolymer was subjected to DSC (Differential Scanning calorimetry) thermal analysis, working as described above, for the purpose of measuring the glass transition temperature (T.sub.g) which was found to be equal to −8° C.

[0058] Said elastomeric copolymer was also subjected to elongation at break, determined in accordance with the ISO 37:2017 standard, which was found to be equal to 67%.

Example 2 (Invention)

Synthesis of Elastomeric Copolymer With Sulfur (70% by Weight) and Garlic Essential Oil (30% by Weight)

[0059] 7 g of pure sulfur [elemental sulfur in the orthorhombic crystalline form (S.sub.8) of Sigma-Aldrich] was charged into a 60 ml glass autoclave equipped with a magnetic stirrer: the autoclave was heated to 160° C. and maintained at said temperature for 10 minutes, obtaining the melting of the sulfur, which becomes a yellow liquid. 3 g of liquid garlic essential oil (having the following composition: diallyl disulphide 50% by weight, diallyl trisulphide 13% by weight, allyl sulphide 9%, other compounds 28% by weight—Naissance) was then added, drop by drop, to said liquid: the whole was maintained, under stiffing, at 160° C., for 3 minutes, obtaining a solution which remains still fluid and takes on an intense red colour. The fluid solution thus obtained was poured into a Teflon mould that was closed and heated to 120° C. in an oven: said fluid solution was maintained at said temperature for 12 hours, yielding an elastomeric copolymer black in colour and with translucent appearance.

[0060] Said elastomeric copolymer was subjected to DSC (Differential Scanning calorimetry) thermal analysis, working as described above, for the purpose of measuring the glass transition temperature (T.sub.g), which was found to be equal to −16° C.

[0061] Said elastomeric copolymer was also subjected to elongation at break, determined in accordance with the ISO 37:2017 standard, which was found to be equal to 74%.

Example 3 (Invention)

Synthesis of Elastomeric Copolymer With Sulfur (80% by weight) and Divinyl Disulphide (20% by Weight)

[0062] 8 g of pure sulfur [elemental sulfur in the orthorhombic crystalline form (S.sub.8) of Sigma-Aldrich] was charged into a 60 ml glass autoclave equipped with a magnetic stirrer: the autoclave was heated to 160° C. and maintained at said temperature for 10 minutes, obtaining the melting of the sulfur, which becomes a yellow liquid. 2 g of liquid divinyl disulphide (Sigma-Aldrich) was then added, drop by drop, to said liquid: the whole was maintained, under stiffing, at 160° C., for 3 minutes, obtaining a solution which remains still fluid and takes on an intense red colour. The fluid solution thus obtained was poured into a Teflon mould that was closed and heated to 120° C. in an oven: said fluid solution was maintained at said temperature for 12 hours, obtaining an elastomeric copolymer black in colour and with translucent appearance.

[0063] Said elastomeric copolymer was subjected to DSC (Differential Scanning calorimetry) thermal analysis, operating as described above, for the purpose of measuring the glass transition temperature (T.sub.g), which was found to be equal to −8° C.

[0064] Said elastomeric copolymer was also subjected to elongation at break, determined in accordance with the ISO 37:2017 standard, which was found to be equal to 82%.

Example 4 (Invention)

Synthesis of Elastomeric Copolymer With Sulfur (70% by Weight) and Divinyl Disulphide (30% by Weight)

[0065] 7 g of pure sulfur [elemental sulfur in the orthorhombic crystalline form (S.sub.8) of Sigma-Aldrich] was charged into a 60 ml glass autoclave equipped with a magnetic stirrer: the autoclave was heated to 160° C. and maintained at said temperature for 10 minutes, obtaining the melting of the sulfur, which becomes a yellow liquid. 3 g of liquid divinyl disulphide (Sigma-Aldrich) was then added, drop by drop, to said liquid: the whole was maintained, under stiffing, at 160° C., for 3 minutes, obtaining a solution, which remains still fluid, and takes on an intense red colour. The fluid solution thus obtained was poured into a Teflon mould that was closed and heated to 120° C. in an oven: said fluid solution was maintained at said temperature for 12 hours, obtaining an elastomeric copolymer black in colour and with translucent appearance.

[0066] Said elastomeric copolymer was subjected to DSC (Differential Scanning calorimetry) thermal analysis, working as described above, for the purpose of measuring the glass transition temperature (T.sub.g), which was found to be equal to −12° C.

[0067] Said elastomeric copolymer was also subjected to elongation at break, determined in accordance with the ISO 37:2017 standard, which was found to be equal to 63%.