Silsesquioxane resin with high strength and fracture toughness and method for the preparation thereof
AssigneesDow Corning Corporation, Massachusetts Institute of Technology
InventorsDimitris Elias Katsoulis, Zhongtao Li, Frederick Jerome McGarry, Bihn Thanh Nguyen, Bizhong Zhu
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Abstract
A cured silsesquioxane resin and method for its preparation are disclosed. By using a silyl-terminated hydrocarbon in the hydrosilylation reaction curable composition used to prepare the cured silsesquioxane resin, the cured silsesquioxane resin has improved strength and toughness without significant loss of modulus. A typical silyl-terminated hydrocarbon useful in this invention is silphenylene.
Claims20
A hydrosilylation reaction curable composition comprising:
- (A) a silsesquioxane copolymer comprising units that have the empirical formula R1aR2bR3cSiO(4-a-b-c)/2, wherein a is zero or a positive number, b is zero or a positive number, c is zero or a positive number, with the provisos that 0.8≦(a+b+c)<3.0 and component (A) has an average of at least two R1 groups per molecule, each R1 is a functional group independently selected from the group consisting of hydrogen atoms and monovalent hydrocarbon groups having aliphatic unsaturation, each R2 is a monovalent hydrocarbon group selected from nonfunctional groups and R1, each R3 is a monovalent hydrocarbon group selected from nonfunctional groups and R1;
- (B) a silyl-terminated hydrocarbon having the general formula
- where R1 and R2 are as described above for component (A), with the provisos that when R1 in component (A) is a hydrogen atom, R1 in component (B) is an unsaturated monovalent hydrocarbon group and when R1 in component (A) is an unsaturated monovalent hydrocarbon group, R1 in component (B) is a hydrogen atom, and R4 is a divalent hydrocarbon group;
- and
- (C) a hydrosilylation reaction catalyst.
A method for preparing a hydrosilylation reaction curable composition comprising:
- (I) mixing
- (A) a silsesquioxane copolymer comprising units that have the empirical formula R1aR2bR3cSiO(4-a-b-c)/2, wherein a is zero or a positive number, c is zero or a positive number, with the provisos that 0.8 ≦(a+b+c)≦3.0 and component (A) has an average of at least 2 R1 groups per molecule, and each R1 is a functional group independently selected from the group consisting of hydrogen atoms and monovalent hydrocarbon groups having aliphatic unsaturation, and each R2 is a monovalent hydrocarbon group independently selected from the group consisting of nonfunctional groups and R1, and each R3 is a monovalent hydrocarbon group independently selected from the group consisting of nonfunctional groups and R1;
- (B) a silyl-terminated hydrocarbon having the general formula
- where R1 and R2 are as described above for component (A), with the provisos that when R1 in component (A) is a hydrogen atom, R1 in component (B) is an unsaturated monovalent hydrocarbon group and when R1 in component (A) is an unsaturated monovalent hydrocarbon group, R1 in component (B) is a hydrogen atom, and R4 is a divalent hydrocarbon group;
- and
- (C) a hydrosilylation reaction catalyst.
Dependencies are inferred from the claim text.