PREPARATION AND CHARACTERIZATION OF POLY ( METHYL METHACRYLATE ) ( PMMA ) AND POLY ( VINYL CHLORIDE ) ( PVC ) ALLOYS
Alloys of Poly (Methyl methacrylate) (PMMA) and Poly (vinyl Chloride) (PVC) were prepared by solvent casting techniques. Physiochemical characteristics of the products were studied. It was found that at certain relative concentration, some of these properties were enhanced, while in some, degraded relative to the constituent homopolymers. These results were interpreted in terms of the interactions between the components of these blends. By means of FT infra red studies, it was established that functional groups were the major players in interactions. Other modes include dipole-dipole, van der waals and mere physical entanglements.
Polymer Blends and Alloys
Overview. Rheology of two-phase blends. Practical aspects of processing of blends. Compatibilization and reactive blending. Practical techniques for studying blend microstructure. Modelling the properties of polymer blends. Toughened polymers. Blends containing liquid crystal polymers. Fibre forming blends and in situ fibre composites. References. Index.
The reactive extrusion of polyethylene/polypropylene blends
The objective of this work was to investigate the compatibilization of a blend of linear low density polyethylene with polypropylene by Injection of a free radical initiator during extrusion. The reactive extrusion process utilized a single screw extruder equipped with two static mixers. The initiator was injected into the extruder feedport and temperature programming used to cause most reaction to occur within the static mixers. Although elongation at yield was increased by 37 percent, impact strength and yield strength decreased by 17 and 54 percent, respectively. Scanning electron microscopy showed that the maximum size of the dispersed phase decreased from a maximum size of four microns to less than two microns upon addition of initiator. Size exclusion chromatography (SEC), temperature rising elution chromatography (TREF), and differential scanning calorimetry showed that the polypropylene in the blend was degrading while the polyethylene was increasing in molecular size. The combination of SEC and TREF was particularly useful in elucidating this result. No copolymer was discerned by any of the methods used.