Functionalized copolymers of isoolefins and diolefins and their use as compatibilizers
Functionalized copolymers of isoolefins and conjugated diolefins, methods of preparing the copolymers, and their use as compatibilizers are disclosed. The diolefin monomer units of the co-polymer are modified at the C—C double bond along the backbone of the copolymer to include an oxygen containing functional group such as epoxide, ester or alcohol. The functionalized copolymers improve the wettability of a non-hydrophilic surface towards hydrophilic polymer and allows for the formation of homogenous layers of the hydrophilic polymers. In particular, the spreading of a hydrophilic polymer on a non-hydrophilic substrate is facilitated by applying the co-polymers as an interfacial layer between the two incompatible materials. The resulting coated substrates exhibit resistance to protein adsorption and cell growth after grafting. The co-polymers are especially suited in the coating of biomedical devices where a high degree of uniformity of the coated surface is required.
1. A substrate comprising a butyl rubber surface coated with a compatibilizer for increasing the wettability of the butyl rubber surface towards a hydrophilic polymer, the compatibilizer comprising a functionalized copolymer comprising repeating units derived from at least one C 4 -C 8 isoolefin and repeating units derived from at least one C 4 -C 16 conjugated diolefin, wherein the copolymer comprises one or more units derived from the at least one conjugated diolefin wherein a C—C double bond along a backbone of the copolymer prior to functionalization is functionalized with an oxygen containing functional group in the functionalized copolymer.
2. The substrate of claim 1 , wherein the oxygen containing functional group is epoxide, hydroxyl, or —OC(O)—R, wherein R is H, C 1-6 alkyl, C 1-6 alkyl substituted with —O—C 1-6 alkyl, C 1-6 alkyl substituted with —C(O)R′ or C 1-6 alkyl substituted with —O—C 1-6 alkyl-C(O)R′, where R′ is H, OH, C 1-6 alkyl or —O—C 1-6 alkyl.
3. The substrate of claim 2 , wherein the functionalized copolymer comprises one or more functionalized isoprene units represented by the formula:
where R is H, C 1-6 alkyl, C 1-6 alkyl substituted with —O—C 1-6 alkyl, C 1-6 alkyl substituted with —C(O)R′ or C 1-6 alkyl substituted with —O—C 1-6 alkyl-C(O)R′,
where R′ is H, OH, C 1-6 alkyl or —O—C 1-6 alkyl.
4. The substrate of claim 2 , wherein the functionalized copolymer has a weight average molecular weight of about 250,000 to about 1,500,000 g/mol.
5. The substrate of claim 2 , wherein the copolymer prior to functionalization comprises about 0.5 mol % to about 20 mol % of the repeating units derived from the conjugated diolefin and about 80 mol % to about 99.5 mol % of the repeating units derived from the isoolefin.
6. The substrate of claim 2 , wherein the copolymer prior to functionalization comprises units derived from isobutylene.
7. The substrate of claim 2 , further comprising a hydrophilic polymer coated on the compatibilizer.
8. The substrate of claim 1 , wherein the oxygen containing functional group is —OC(O)—R, wherein R is H, C 1-6 alkyl, C 1-6 alkyl substituted with —O—C 1-6 alkyl, C 1-6 alkyl substituted with —C(O)R′ or C 1-6 alkyl substituted with —O—C 1-6 alkyl-C(O)R′, where R′ is H, OH, C 1-6 alkyl or —O—C 1-6 alkyl.
9. The substrate of claim 8 , wherein the functionalized copolymer comprises one or more functionalized isoprene units represented by the formula:
where R is H, C 1-6 alkyl, C 1-6 alkyl substituted with —O—C 1-6 alkyl, C 1-6 alkyl substituted with —C(O)R′ or C 1-6 alkyl substituted with —O—C 1-6 alkyl-C(O)R′,
where R′ is H, OH, C 1-6 alkyl or —O—C 1-6 alkyl.
10. The substrate of claim 9 , wherein the functionalized copolymer has a weight average molecular weight of about 250,000 to about 1,500,000 g/mol.
11. The substrate of claim 10 , wherein the copolymer prior to functionalization comprises about 0.5 mol % to about 20 mol % of the repeating units derived from the conjugated diolefin and about 80 mol % to about 99.9 mol % of the repeating units derived from the isoolefin.
12. The substrate of claim 11 , wherein the copolymer prior to functionalization comprises units derived from isobutylene.
13. The substrate of claim 12 , further comprising a hydrophilic polymer coated on the compatibilizer.
14. The substrate of claim 9 , wherein the copolymer prior to functionalization comprises about 0.5 mol % to about 20 mol % of the repeating units derived from the conjugated diolefin and about 80 mol % to about 99.5 mol % of the repeating units derived from the isoolefin.
15. The substrate of claim 9 , wherein the copolymer prior to functionalization comprises units derived from isobutylene.
16. The substrate of claim 1 , wherein the functionalized copolymer comprises one or more functionalized isoprene units represented by the formula:
where R is H, C 1-6 alkyl, C 1-6 alkyl substituted with —O—C 1-6 alkyl, C 1-6 alkyl substituted with —C(O)R′ or C 1-6 alkyl substituted with —O—C 1-6 alkyl-C(O)R′,
where R′ is H, OH, C 1-6 alkyl or —O—C 1-6 alkyl.
17. The substrate of claim 1 , wherein the functionalized copolymer has a weight average molecular weight of about 250,000 to about 1,500,000 g/mol.
18. The substrate of claim 1 , wherein the copolymer prior to functionalization comprises about 0.5 mol % to about 20 mol % of the repeating units derived from the conjugated diolefin and about 80 mol % to about 99.5 mol % of the repeating units derived from the isoolefin.
19. The substrate of claim 1 , wherein the copolymer prior to functionalization comprises units derived from isobutylene.
20. The substrate of claim 1 , further comprising a hydrophilic polymer coated on the compatibilizer.