Phase separation time/temperature dependence of thermoplastics-modified thermosetting systems

Abstract

The cure-induced phase separation processes of various thermoplastics(TP)-modified thermosetting systems which show upper critical solution temperature (UCST) or lower critical solution temperature (LCST) were studied with emphasis on the temperature dependency of the phase separation time and its potential application in the cure time-temperature processing window. We found that the phase separation time/temperature relationship follows the simple Arrhenius equation. The cure-induced phase separation activation energy E a (ps) generated from the linear fitting of the Arrhenius equation is irrelevant to the detection means of phase separation time. We also found that E a (ps) is insensitive to TP content, TP molecular weight and curing rate, but it changes with the cure reaction kinetics and the chemical environment of the systems. With the established phase separation time-temperature dependence relation, we can easily establish the whole cure time-temperature transformation (TTT) diagram with morphology information which is a useful map for the TP/TS composites processing industry.

Self-Assembly of Copolyesters into Stereocomplex Crystallites Tunes the Properties of Polyester Nanoparticles

“…SCs have a significantly lower critical concentration threshold for precipitation from organic solvents in comparison to their homochiral counterparts. Therefore, these l - and d -interactions lead to the self-assembly of stable SC nuclei, which then start to grow. , There are several studies on various materials that self-assemble into nanostructures, for example, on proteins but also on phase separations of copolymers and polymer blends. − …”

Rheology and pressure–volume–temperature behavior of the thermoplastic poly(acrylonitrile-butadiene-styrene)-modified epoxy-DDS system during reaction induced phase separation

“…In these processes, polymer synthesis and shaping take place in a single operation, which involves the conversion of liquid monomers and/or polymers into solid crosslinked polymers. [13][14][15][16][17] Very few systematic studies have been reported on the evolution of rheology in thermoset/thermoplastic (TS/TP) systems; [18][19][20][21] most of the studies are focused on final mechanical properties. The typical isothermal curing of thermoset/thermoplastic based blends is accompanied by the polymerization shrinkage and an increase in complex viscosity due to vitrification of the thermoset-rich phase.…”