Polymer Blends

Abstract

The physical approach of blending polymers to develop new or improved polymeric products has been an extremely active area of academic and industrial research for nearly three decades, owing to the much higher costs associated with the alternative of chemical synthesis of new polymers. This activity has been paced by the rapid commercialization of products based on blend technology, including polyamide‐, polyester‐, styrenic‐, vinyl‐, acrylic‐, olefinic‐, and epoxy‐ based materials. The basic principles needed to practice this approach are reviewed, including molecular and thermodynamic factors affecting blend‐phase behavior (miscibility or compatibility), phase morphology, processing, interfacial behavior, and chemical reactions that can occur. General trends and examples of physical properties are given, with special emphasis on the important commercial developments, followed by speculations about future developments.

Phase morphology and thermomechanical analysis of poly(styrene‐co‐acrylonitrile)/ethylene–propylene–diene monomer blends: Uncompatibilized and reactively compatibilized blends with two mixing sequences

“…Therefore, it is brittle in impact testing 9–13. To improve this sometimes undesirable situation caused by unstable craze deformation, it is often modified with rubber particles 14–18. Often, however, the immiscibility and incompatibility of the rubber with SAN produce poor physical properties in the blend 19–24.…”

Chemical interaction in blends of polyamide and butyl rubbers

“…Commonly, block and graft copolymers that possess segments with chemical structures or solubility parameters similar to those of the polymers being blended are effective compatibilizing agents. It is well known that these may be preformed and added to the mixture of polymers undergoing compatibilization, or they may be generated in situ by reaction between coreactive functional groups on the polymers or free‐radical generation and recombination reactions 1–3…”

“…Both are well known for their barrier characteristics as homopolymers 4, 5. Polyamides, however, have limited impact resistance and a high flexural modulus,2 whereas butyl rubbers display typical elastomeric characteristics 5. When butyl rubber (IIR) and its halogenated derivatives, such as bromobutyl rubber (BIIR), are blended with polyamides, the result is a softer material with a reduced flexural modulus.…”

“…A literature search on blends of polyamides with various types of rubber shows activity on blends of this nature over the last 10–15 years 2, 6–12. Dynamic vulcanization is one method described in the literature to prepare blends with useful properties.…”

A novel approach for an in-line atmospheric plasma-treatment of polymers and reinforcements during extrusion

“…Regarding polymer-blends, it is agreed upon, that a significant number of polymer blends is immiscible, due to the unfavourable interaction between molecular segments of the polymer-blend components [27]. Thus, interfacially active copolymers are added [27][28][29][30][31][32][33][34][35][36][37][38] or formed in situ during processing by an interfacial reaction of added functionalized polymeric components [27,[38][39][40][41][42]. The aim of this interfacial compatibilization is to lower interfacial tension, to decrease the dispersed phase domain size, to hinder coalescence, to improve adhesion and to stabilize the morphology [38,[43][44][45][46].…”