Rubber–Plastic Blends: Structure–Property Relationship

Abstract

Blends of rubbers and plastics have both an extensive history and a variety of applications, since blends retain most of the stiffness of thermoplastics and impart some of the resilience and the impact toughness of rubbers. Most useful blends have morphology of rubber dispersed in the thermoplastic matrix since the reverse does not lead to same degree of utility. The properties of these blends depend on the relative ratio of the rubber and the plastic and, more importantly, on the morphology of the dispersion. A very large research effort has been made in an attempt to control and determine the morphology and the interface of the rubber and the plastic as well as understand the effect of the rubber dispersion on the properties of the blend. Blends are important commercially since they allow the development of unique properties from the same constituents with small changes in the relative amounts or the dispersion. The conventional prac tice of blend formation is the melt mixing of the components although, in some cases, a polymerization process that enables the direct production of the binary blend is possible. These direct production processes are efficient since they pro duce the desired morphology and the required polymers in a single step. Blends have become extremely important for the development of polyolefin rubbers and plastics since a large variety can be mixed in a wide composition ratio to produce novel properties. These blends are easily made and have stable dispersion during processing due to only small thermodynamic differences between the various polyolefins compared with engineering thermoplastics. This chapter describes the physics and the chemistry and more importantly the relationship between the structure of the blend and its properties. This area has been continually progressed [1] and reviewed [2]. Progress arises from new materials and new technologies for making rubber-plastic blends. The area of polyethylene blends cited above is an important development. The Encyclopedia of Polymer Blends: Volume 3: Structure, First Edition. Edited by Avraam I. Isayev.

Effect of Compatibilization on Biobased Rubber-Toughened Poly(trimethylene terephthalate): Miscibility, Morphology, and Mechanical Properties

“…Unfortunately, most of them are synthetic elastomers that lower the overall biobased content of the blend system. Therefore, natural rubber (NR) being a completely biobased toughening agent is a more environmentally conscious alternative, which has yet to be explored, to the best of the authors’ knowledge, though there still remains the issue of phase separation and immiscibility between such polymeric components when blending thermoplastics with rubbers that affect the final macroscopic properties, requiring further compatibilization. , Not only are the individual polymers responsible for the performance of these types of blends, the final morphology also plays a significant role, with the distribution, size, and shape of the dispersed phase being affected during melt processing. Therefore, the use of compatibilizers to influence the intrinsic parameters such as interfacial adhesion, while monitoring the effect the extrinsic parameters such as strain rate and temperature have on them, are important characteristics when toughening rubber-modified ductile matrices …”