Influences of the Periodicity in Molecular Architecture on the Phase Diagrams and Microphase Transitions of the Janus Double-Brush Copolymer with a Loose Graft

Abstract

The backbone of the Janus double-brush copolymer may break during long-term service, but whether this breakage affects the self-assembled phase state and microphase transitions of the material is still unknown. For the Janus double-brush copolymers with a periodicity in molecular architecture ranging from 1 to 10, the influences of the architectural periodicity on their phase diagrams and order–disorder transitions (ODT) were investigated by the self-consistent mean field theory (SCFT). In total, nine microphases with long-range order were found. By comparing the phase diagrams between copolymers of different periodicity, a decrease in periodicity or breakage along the copolymer backbone had nearly no influence on the phase diagrams unless the periodicity was too short to be smaller than 3. For copolymers with neutral backbones, a decrease in periodicity or breakage along the copolymer backbone reduced the critical segregation strengths of the whole copolymer at ODT. The equations for the critical segregation strengths at ODT, the architectural periodicity, and the volume fraction of the backbone were established for the Janus double-brush copolymers. The theoretical calculations were consistent with the previous theoretical, experimental, and simulation results.

Polyacrylate Thermoplastic Elastomer Replacing SBS for Modified Asphalt

“…A synthesis scheme of polyacrylate thermoplastic elastomer is proposed by summarizing the existing monomers, polymerization methods and initiator molecular structures, which provides a guideline for replacing SBS and for improving the comprehensive performance and service life of modified asphalt. Keywords: Thermoplastic Elastomer; Acrylate Copolymer; Long Life Material; Asphalt Modifier; Synthesis Scheme [8,9]。因此，有必要设计性能更好的新型 TPE 分子替代 SBS 用于改性沥青 [5,10]。 在设计新型 TPE 时，其硬嵌段和软嵌段要求分别 具有高、低的玻璃化转变温度(T g )，以分别提高沥青 的高温和低温性能 [7,11]。丙烯酸酯类聚合物能形成富 有弹性或耐高温的材料 [12,13]，有着耐水性、耐油性、 耐候性、耐碱性、耐氧性、耐光性和臭味少等特点 [12,14]。而且丙烯酸酯可以方便地和苯乙烯等多种单体共 聚合 [9,13]，为 TPE 的分子设计和材料性能调控提供 了很大的灵活性 [12,15] [9,13,17]。对于线型 TPE，宜采用活性聚合方 法，每个嵌段选用单体进行共聚以调节 T g [9]。对于梳 型 TPE， 建议的合成路线为： 先制备出遥爪接枝链 [18]…”