Phase-diagram for Irregular and Non-Symmetric Cross-linked Polymer Blends

TL;DR

This paper investigates the phase behavior of a two-polymer blend with irregular, non-symmetric cross-links, revealing conditions for complete or partial segregation and the absence of microphase transitions, supported by experimental validation.

Contribution

It introduces a phase diagram for irregular, non-symmetric cross-linked polymer blends, highlighting segregation behavior and phase transition absence.

Findings

Complete segregation occurs at low temperatures with weak, non-permanent cross-links.

Partial segregation is observed with stronger or more permanent cross-links.

No phase transition exists between homogeneous and microphase states in non-symmetric systems.

Abstract

We consider here a blend made of two types of polymers, $A$ and $B$, of different chemical nature. At high temperature the homogeneous mixture is cross-linked. As the temperature is lowered, the two species try to segregate but are kept together by the cross-links. We show that for inhomogeneous, non-regular and non-permanent cross-links, there is a complete segregation at low temperatures if the system is just weakly cross-linked and partial segregation, otherwise. We also demonstrate that there is no phase transition between the homogeneous phase and the microphase for non-symmetric systems. Our analysis is checked with the experiment.