On the properties and processing of polyethylene terephthalate/styrene-butadiene rubber blend

The mixing of incompatible polymers such as polyethylene terephthalate (PET ) and styrene-butadiene rubber (SBR) produces a blend with poor mechanical and impact properties, because polymeric phases interact weakly with each o ther and segregate. The use of SBR grafted with maleic anhydride (MAH) incr eases the compatibility of the SBR-PET system by generating higher interact ions and chemical links between the ingredients of the blend. The induced c ompatibility is reflected in the 2.5-fold increase in the impact resistance of the blend as compared to that of pure PET. The grafting reaction to pro duce SBR-g-MAH is carried out by reactive extrusion using a reaction initia tor benzoyl peroxide (BPO), and the extent of the reaction depends on the c oncentration of MAH and BPO. Results indicate the close relationship betwee n processing conditions and microstructural parameters, such as particle di ameter and interparticle distances of the dispersed rubber phase, necessary to achieve the optimum impact resistance.