The effects of intramolecular interactions of random copolymers on the phase behavior of polymer mixtures

Abstract

To explore the effects of intramolecular interactions within the copolymer on the phase separation behavior of polymer blends, copolymers having two different types of intramolecular interactions, i.e., intramolecular repulsion and intramolecular attraction were prepared. In this study, poly(styrene-co-methylmethacrylate) (P(S-MMA)) having intramolecular repulsion caused by positive interaction between styrene and MMA and poly(styrene-co-ethylmethacrylate) (P(S-EMA)) and poly(styrene-co-cyclohexylmethacrylate) (P(S-CHMA)) having intramolecular attraction caused by negative interaction between styrene and methacrylate were blended with tetramethyl polycarbonate (TMPC). The phase behavior of blends was examined as a function of copolymer composition and blend composition. TMPC formed miscible blends with styrenic copolymers containing less than certain amount of methacrylate. The phase separation temperature of TMPC blends with copolymer such as P(S-MMA) and P(S-EMA), first increases with methacrylate content, goes through a maximum and then decreases just prior to the limiting content of methacrylate for miscibility, while that of TMPC blends with P(S-CHMA) always decreases. The calculated interaction energy for TMPC-P(S-EMA) pair is negative and monotonically increases with EMA content of the copolymer. Such behavior contradicted the general notion that systems with more favorable energetic interactions have higher LCST. The detailed inspection of the lattice-fluid theory related to the phase behavior was performed to explain such behavior.

Contribution of the melting stage to the evolution of the morphology and chemical conversion of immiscible polyamide/polyethylene blends in twin‐screw extruders

“…Reactive compatibilization is used extensively to control the size and stability of the dispersed phase and to improve the interfacial characteristics of immiscible polymer pairs. [1][2][3][4] During mixing, reactive functionalized polymers form in situ block or graft copolymers at the interface of the blend components. It is now clear that these graft or block copolymers induce a large reduction both in the interfacial tension and in the dispersed phase coalescence due to steric stabilization.…”

Phase behavior of binary and ternary blends having the same chemical components and compositions

“…DMPC is miscible with TMPC but is immiscible with PS. [4][5][6][7][8]24 According to the binary interaction model, the unfavorable interaction of DMPC with PS and the favorable interaction of DMPC and TMPC both act against miscibility of the copolycarbonate with PS.…”

“…When homopolymer/homopolymer blend is not immiscible, a new miscible blend involving immiscible binary pair often produced via two different routes; Blending of a homopolymer with copolymer that composed of binary pair having strong intramolecular repulsion is known a useful route to prepare a miscible blend. [1][2][3][4][5][6][7][8] The other way preparing miscible blend is the homogenization of two immiscible polymers by adding a third polymer that is miscible with each component. [9][10][11][12][13][14][15][16][17] According to the binary interaction model, 1-3 the former method might be a useful route in developing miscible blends.…”

“…In the previous researches, various miscible blends have been developed via copolymerization. [4][5][6][7][8] The latter method also often used to develop a new miscible blend. However, this method was not successful in developing a new miscible blend unless the third component that is miscible with each component of blend is major component in blend.…”

“…The temperature at which phase separation caused by lower critical solution temperature, LCST, was measured by an annealing technique to access the closest true equilibrium temperature. 6,[25][26][27] …”