Poly(arylene ether)-polysiloxane composition and method
View Patent ↗A thermoplastic composition includes a poly(arylene ether) and a poly(arylene ether)-polysiloxane block copolymer. The thermoplastic composition is prepared by a method that includes oxidatively copolymerizing a monohydric phenol and a hydroxyaryl-terminated polysiloxane. The method is simpler than prior methods of preparing poly(arylene ether)-polysiloxane block copolymers by linking pre-formed poly(arylene ether) and polysiloxane blocks. The method is also produces greater incorporation of polysiloxane into the poly(arylene ether)-polysiloxane block copolymer than prior methods of copolymerizing monohydric phenols and hydroxyaryl-terminated polysiloxane.
1. A method of preparing a thermoplastic composition, comprising:
oxidatively copolymerizing a monohydric phenol and a hydroxyaryl-terminated polysiloxane to form a thermoplastic composition;
wherein the oxidative copolymerization is initiated in the presence of at least 50 weight percent of the hydroxyaryl-terminated polysiloxane and less than or equal to 50 weight percent of the monohydric phenol;
wherein the oxidative copolymerization is conducted with a reaction time greater than or equal to 110 minutes;
wherein the hydroxyaryl-terminated polysiloxane comprises, on average, 35 to 80 siloxane repeating units;
wherein the hydroxyaryl-terminated polysiloxane constitutes 1 to 8 weight percent of the combined weight of the monohydric phenol and the hydroxyaryl-terminated polysiloxane; and
wherein the thermoplastic composition incorporates greater than 80 weight percent of the hydroxyaryl-terminated polysiloxane into the poly(arylene ether)-polysiloxane block copolymer.
2. The method of claim 1 , wherein the thermoplastic composition comprises 1 to 8 weight percent siloxane repeating units and 12 to 99 weight percent arylene ether repeating units.
3. The method of claim 1 , wherein the thermoplastic composition has a weight average molecular weight of at least 30,000 mass units.
4. The method of claim 1 , wherein the thermoplastic composition incorporates greater than 90 weight percent of the hydroxyaryl-terminated polysiloxane into the poly(arylene ether)-polysiloxane block copolymer.
5. The method of claim 1 ,
wherein the monohydric phenol is 2,6-dimethylphenol;
wherein the hydroxyaryl-terminated polysiloxane is a eugenol-capped polydimethylsiloxane comprising 35 to 60 dimethylsiloxane units;
wherein the oxidative copolymerization is initiated in the presence of at least 90 weight percent of the hydroxyaryl-terminated polysiloxane and 2 to 20 weight percent of the monohydric phenol;
wherein the oxidative copolymerization is conducted with a reaction time of 170 to 220 minutes; and
wherein the hydroxyaryl-terminated polysiloxane constitutes 2 to 7 weight percent of the combined weight of the monohydric phenol and the capped polysiloxane.