Phase Separation Kinetics of a Polymer Blend Modified by Random and Block Copolymer Additives

Abstract

The phase separation behavior of polymer blends modified by copolymer additives has been studied using light scattering techniques. Block and random copolymers with equal styrene and butadiene content as well as a random copolymer with unequal monomer composition were used as additives at a concentration of 2.5% (w/w). The symmetric additives lowered the phase boundary with increasing concentration while the asymmetric additive destabilized the phase boundary. The data demonstrate a slowing of the kinetics with the addition of any of the copolymers. In comparison to the binary blend, droplet sizes in the early stage were smaller with added symmetric block copolymer and larger with added asymmetric random copolymer. Scaling analysis of the intermediate stage kinetics showed some deviations relative to binary scaling results. Deviations from Porod's law indicate that modifications to the interfacial boundary are most notable for the asymmetric random copolymer. Self-similarity was seen to hold for all of the systems.

Using neutron reflectivity to determine the dynamic properties of a copolymer in a homopolymer matrix

“…The process that is dominant in this technique is the segregation of the copolymer from a blend to a biphasic interface. Many studies have investigated the surface and interfacial properties of polymer blend thin films, including wetting phenomena, surface and interfacial segregation, and phase separation 17–39. In the case of surface segregation, small differences in the surface energy between the components can drive the segregation process of the lower surface energy component of a polymer blend to an interface.…”

Polymerization‐induced phase separation and resulting thermomechanical properties of thermosetting/reactive nonlinear polymer blends: A review

“…[23][24][25][26][27][28][29] In addition to these methods, cloud-point, dielectric relaxation spectroscopy, and temperature-jump light-scattering and rheometry measurements have also been widely used to investigate PIPS in thermosets. [30][31][32][33][34] Jyotishkumar et al 24 traced the dynamics of phase separation and the final morphologies of a poly(acrylonitrile-butadiene-styrene) (ABS) modified diglycidyl ether of bisphenol A (DGEBA) epoxy system in situ with OM, DSC, rheometry, and small-angle laser light scattering. AFM investigations of ABS showed that the crosslinked polybutadiene (PB) phase was dispersed in the SAN continuous phase.…”

Effects of Hydrophobic Modifications and Phase Transitions of Polyvinylamine Hydrogel Films on Reversible CO2 Capture Behavior: Comparison between Copolymer Films and Blend Films for Temperature‐Responsive CO2 Absorption

“…Another approach to prepare material with unique properties that combines the advantages of two or more polymers is the blending method, which uses conventional mixing technologies with much lower costs than copolymerization. [24,[30][31][32][33][34] The membrane of a PVAm/ poly(ethylene glycol) (PEG) (9:1) blend, for example, showed significantly increased CO 2 permeability and selectivity against CH 4 than the pure PVAm membrane, because the addition of PEG inhibits the crystallization of PVAm that prevents gas transport. [35] In this study, we prepared a series of hydrogel films by modified PVAm and tested the amount of CO 2 released in the low temperature (75 °C) regeneration process after absorbing CO 2 at 30 °C.…”