V. Percec, Y. Tsuda
1991
Citations
0
Influential Citations
18
Citations
Journal
Polymer
Abstract
Abstract The isomorphism of polyether chains based on 1-(4-hydroxyphenyl)-2-(2-methyl-4-hydroxyphenyl)ethane (MBPE) and α,ω-dibromoalkanes (MBPE-X, MBPE-X/Y(A/B) and MBPE-X/Y/Z(A/B/C), where X, Y, Z are the number of methylene units in the spacer and A/B/C the molar ratio between each spacer), most of which display virtual mesophases, was investigated in their crystalline and liquid-crystalline phases. Binary mixtures of polyethers with even-even, even-odd and odd-odd spacers, binary copolyethers and polyethers, binary copolyethers and copolyethers, ternary copolyethers and polyethers, and ternary mixtures of polyethers were all investigated. Out of 20 mixtures studied, only eight were isomorphic either within both their crystalline and liquid-crystalline phases or within only their liquid-crystalline or crystalline phases. The mixtures displaying isomorphism are: MBPE-7/MBPE-9, MBPE-8/MBPE-10, MBPE-5/13(50/50)/MBPE-9/11(50/50), MBPE-5(33)/MBPE-7(33)/MBPE-9(33), MBPE-5/7/9(33/33/33)/MBPE-5, MBPE-5/7/9(33/33/33)/MBPE-7, BPE-8/10(50/50)/MBPE-8/16(50/50) and MBPE-5/7/9(33/33/33)/MBPE-9. In the case of mixtures of homopolymers, the tendency towards isomorphism increases with the decrease of the difference between the spacer length and parity. In the case of mixtures of copolymers with copolymers and of copolymers with homopolymers the tendency towards isomorphism increases by increasing the number of flexible spacers from the copolymer. By analogy with copolymers containing structural units that are isomorphous within mesomorphic phases, mixtures of polymer chains that display virtual mesophases and are isomorphic in their mesophase can be used to determine virtual mesomorphic phase transition temperatures and thermodynamic parameters of the parent homopolymers.