Reactive polystyrene blends, mechanical properties

Specifically, PVC blends with polyethylene, polypropylene, or polystyrene could offer significant potential. PVC offers rigidity combined with flammability resistance. In essence, PVC offers the promise to be the lowest cost method to flame retard these polymers. The processing temperatures for the polyolefins and polystyrene are within the critical range for PVC. In fact, addition of the polyolefins to PVC should enhance its ability to be extruded and injected molded. PVC has been utilized in blends with functional styrenics (ABS and styrene-maleic anhydride co-and terpolymers) as well as PMMA offering the key advantage of improved flame resistance. Reactive extrusion concepts applied to PVC blends with polyolefins and polystyrene appear to be a facile method for compatibilization should the proper chemical modifications be found. He et al. [1997] noted the use of solid-state chlorinated polyethylene as a compatibilizer for PVC/LLDPE blends with a significant improvement in mechanical properties. A recent treatise [Datta and Lohse,... 

Figures 11.3 and 11.4 show that reactive compatibilization can also be used for other types of polymers. Polystyrene is a very brittle polymer and the simple addition of polypropylene already improves the maximum strain. Very significant improvements in ductileness can be achieved by reactive compatibilization. In Fig. 11.4 is indicated that the type of monomer is also important for the mechanical properties of the blend. Both volatility and the...

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