Reactive polystyrene blends, mechanical

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...

The study on this in situ reactive compatibilization of polyolefin and polystyrene, using Friedel-Crafts benzene ring alkylation, was extended to a single screw extrusion process for PE/PS and PP/PS blends [27]. The mechanical characterization of various blends showed that the in situ compatibilization of PE/PS and PP/PS blends was again achieved within the processing time in a single screw extruder. 

Everaert et al. prepared poly (methylene oxide)/ polystyrene-poly (2,6-dimethyl-l, 4 phenylene ether) (POM/(PS/PPE)) and studied the fractionated crystallization of POM when different glass transition temperature matrices were produced by changing the composition of the PS/PPE phases [305,306]. Wilkinson et al. produced a series of polypropylene/polyamide 61 SEES ternary blends. The progressive replacement of SEES by reactive SEES-g-MA reduced the interfacial tension between the components and then the blends could exhibit significant variations in mechanical and thermal behavior [307]. 

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