POLY(ARYLENE ETHER)-POLYSILOXANE COMPOSITION AND METHOD
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 thermoplastic composition prepared by a method, 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; and
wherein the hydroxyaryl-terminated polysiloxane constitutes 1 to 8 weight percent of the combined weight of the monohydric phenol and the hydroxyaryl-terminated polysiloxane.
2 . The thermoplastic composition of claim 1 , wherein the reaction time comprises a build time of 80 to 160 minutes.
3 . The thermoplastic composition 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.
4 . The thermoplastic composition of claim 1 , wherein the thermoplastic composition has a weight average molecular weight of at least 30,000 atomic mass units.
5 . The thermoplastic composition of claim 1 , wherein the thermoplastic composition has a weight average molecular weight of 30,000 to 150,000 atomic mass units.
6 . The thermoplastic composition of claim 1 , wherein the thermoplastic composition has an intrinsic viscosity of at least 0.3 as measured at 25° C. in chloroform.
7 . The thermoplastic composition of claim 1 , wherein the thermoplastic composition has an intrinsic viscosity of 0.3 to 0.6 deciliter per gram as measured at 25° C. in chloroform.
8 . The thermoplastic composition of claim 1 , wherein the thermoplastic composition comprises less than 25 weight percent of molecules having a molecular weight less than 10,000 atomic mass units.
9 . The thermoplastic composition of claim 8 , wherein the molecules having a molecular weight less than 10,000 atomic mass units comprise, on average, 5 to 10 weight percent siloxane repeating units.
10 . The thermoplastic composition of claim 1 , wherein the thermoplastic composition comprises less than 25 weight percent of molecules having a molecular weight greater than 100,000 atomic mass units.
11 . The thermoplastic composition of claim 10 , wherein the molecules having a molecular weight greater than 100,000 atomic mass units comprise, on average, 3 to 6 weight percent siloxane repeating units.
12 . The thermoplastic composition of claim 1 , wherein the monohydric phenol consists of 2,6-dimethylphenol, and wherein the thermoplastic composition comprises less than or equal to 0.4 weight percent of 2,6-dimethylphenoxy groups.
13 . The thermoplastic composition of claim 1 , wherein the monohydric phenol consists of 2,6-dimethylphenol, and wherein the thermoplastic composition comprises 0.2 to 0.4 weight percent of 2,6-dimethylphenoxy groups.
14 . The thermoplastic composition of claim 1 , wherein the thermoplastic composition incorporates greater than 80 weight percent of the hydroxyaryl-terminated polysiloxane into the poly(arylene ether)-polysiloxane block copolymer.
15 . The thermoplastic composition 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.
16 . The thermoplastic composition of claim 1 ,
wherein the thermoplastic composition comprises less than 25 weight percent of molecules having a molecular weight less than 10,000 atomic mass units;
wherein the molecules having a molecular weight less than 10,000 atomic mass units comprise, on average, 5 to 10 weight percent siloxane repeating units;
wherein the thermoplastic composition comprises less than 25 weight percent of molecules having a molecular weight greater than 100,000 atomic mass units; and
wherein the molecules having a molecular weight greater than 100,000 atomic mass units comprise, on average, 3 to 6 weight percent siloxane repeating units.
17 . The thermoplastic composition of claim 1 ,
wherein the poly(arylene ether) block comprises arylene ether repeating units having the structure
and
wherein the polysiloxane block has the structure
wherein n is 35 to 60; and
wherein the thermoplastic composition has a number average molecular weight of 10,000 to 30,000 atomic mass units.