Due to different polarity and structure between the thermoplastic and elastomeric phases, most thermoplastic elastomers are incompatible. Poor interfacial adhesion and high interfacial tension between rubber and thermoplastic phases are main reasons for incompatibility of these systems. The blends of polypropylene (PP)/ethylene propylene diene monomer (EPDM) containing 20% EPDM may be compatibilized with maleic anhydride grafted PP (PP-g-MAH) and maleic anhydride grafted EPDM (EPDM-g-MAH) ranging from 0 to 6 phr. The dynamic rheological behaviour of the blends in presence of compatibilizer and applying dynamic vulcanization were studied using parallel plate rheometric mechanical spectrometer (RMS) at 190°C. The Cole- Cole and van Gurp-Palmen plots for all samples were plotted to make correlation between rheology and the obtained morphology of the blends. It was found that the complex viscosity (h*) of the dynamic vulcanized blends levelled up with increase of compatibilizer concentration while for un-vulcanized blends it was levelled off for the same ratio of PP/EPDM. Storage modulus of compatibilized samples showed two relaxations shoulder at high concentration of compatibilizer which at low frequencies is attributed to interfacial relaxation and at high frequencies is related to EPDM droplets. There was no considerable difference among intersection frequencies (wc) for un-vulcanized samples which means compatibilizer is more effective in combination with dynamic vulcanization. Morphological study showed that the size of dispersed phase decreased with combination of dynamic vulcanization and Compatibilization.

The Compatibilization effect of a hyperbranched poly(amide-ester) (HBP) on poly(acrylonitrile-butadiene-styrene)/poly(vinylchloride) (ABS/PVC) blends was examined. The effects of the amounts of HBP on mechanical properties of ABS/PVC (80/20, mass ratio) blends were investigated. The results showed that a small quantity of HBP had a significant effect on mechanical properties and can improve the compatibility of the ABS/PVC blends; the tensile strength of the ABS/PVC (80/20) blends reached to a maximum value when HBP content increased to 2 phr and then dropped quickly by adding more HBP, the impact strength of the ABS/PVC (80/20) blend decreased with incorporation of HBP, the higher HBP added, the greater impact strength of ABS/PVC blend decreased. The scanning electron microscopy indicated that the surfaces of ABS/PVC blends were mainly composed of separate tiny droplets and some cavities. When HBP was introduced into ABS/PVC (80/20) blends, the asperity of the surface decreased, and shear band began to form either partially or completely. DSC Analysis also confirmed that HBP could improve the compatibility of the ABS/PVC blends.

In this study, poly carbonate (PC) and poly (ethylene terephthalate) (PET) were reactive melt-blended under two different conditions to produce PC/PET copolymers. For each condition, samples were taken at specified mixing times representative a specific structure of copolymers and each one employed to physically compatibilize a PC/PET blend with a fixed composition. Reactive blending and copolymer structure are described by solubility analysis results. Continues declining and going through a minimum are two trends of solubility versus mixing time depending on reactive blending condition. Decreasing and increasing patterns of solubility curves were attributed to the formation of copolymers with longer and shorter block lengths, respectively, and the level of solubility was related to the amount of produced copolymers. Differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) techniques were employed to investigate blend compatibility. The content and structure of copolymers showed favorable correlation of Tg differences of blend components and PET crystallinity. As expected, Tg of blend components approached to each other by the addition of copolymers, and the copolymers with longer block length caused less Tg differences. The melting point and crystallinity of PET were affected by introducing the copolymers too. In addition to the main melting endotherm, melting endotherm peaks of compatibilized blends had a shoulder that its corresponding melting point and crystallinity are related to the copolymer structure so that the longer length of block copolymer or higher its amount leads to the higher melting points. The SEM micrographs showed that, after the addition of the copolymer, smaller PET particles formed and uniformly dispersed in the PC matrix. A strong correlation between the blend morphology and the level of blend compatibility was demonstrated. The more compatibilized PC/PET blend, the better dispersion of PET particles in the PC matrix was obtained. The results of this study could be a basis for designing and production of compatibilizers suitable to achieve a desired level of compatibility in PC and polyester blends, specially in PC/PET blend.

Most polymer blends are immiscible and need to be compatibilized. Compatibilization can be accomplished either by addition of a compatibilizer or by reactive processing. Grafting has been the most common method for compatibilizing two immiscible polymers during reactive processing. In this work, the reactive blending of EPDM (ethylene- propylene-diene monomer) rubber and SAN (styrene-acrylonitrile) copolymer was studied. The blends were prepared in an internal mixer with three types of organic peroxides as initiator. The effects of initiator type and concentration, EPDM content, and mixing sequences of components were investigated. Blends were separated to their structural components (i.e., SAN, EDPEM, SAN-g-EPDM, and gelled EPDM) which were then characterized by FTIR spectroscopy and SEM microscopy techniques. Mechanical properties including tensile and impact strength as well as elongation-atbreak were measured. From the three initiators used, the blends which have 2,5- dimethyl-2,5-di-(t-butyl peroxy) hexane as initiator show better mechanical properties. Also, SEM studies reveal a good compatibility for SAN/EPDM blends using this initiator. The blend using 40 wt% of EPDM of the mentioned initiator contains 16.24 wt% SANg- EPDM. Impact strength of the blends was affected by mixing sequences of the components. The Blends prepared by mixing sequences of SAN/initiator/EPDM show the highest impact strength of the order of 45 J/m.