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Thermoplastic elastomers (TPEs) are new type of elastomer materials with comparable and sometimes better mechanical properties than conventional elastomers, while having processing characteristics of thermoplastic materials. Thermoplastic vulcanizates (TPE-V) are elastomer/thermoplastic polymer microheterogenic blends in which elastomer phase is crosslinked and dispersed in a continuous thermoplastic matrix. The subject of this study was evaluation of the phase structure and mechanical properties of the TPE-Vs obtained by reactive processing in the molten state of PP and ethylene-octene elastomer (EOE) blend using silane/moisture as crosslinking system. Morphology was studied by scanning electron microscopy (SEM) and thermal behavior of the blends was studied by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and differential thermal analysis (DTA). It was observed that both thermal behavior and mechanical properties of the compositions were very dependent on blend composition when specimens are subjected to heat or mechanical loads. Glass transition temperature (Tg) decreases with increase in concentration of elastomer in TPE-V.

The effect of modification of plasticizer and stabilizer systems on the radiation resistance of flexible PVC compositions for medical applications was studied. Samples were irradiated in a linear accelerator LAE 13/9 of electrons beam with dose of 25 kGy. Biological-chemical and mechanical-physical property data were measured for irradiated and additionally ageing plasticized PVC compositions of modified formulations and compared with those of standard medical grade compositions. Post-irradiated stability of flexible PVC meeting the Pharmacopoeia requirements has been achieved.

Kinetics of decomposition of poly(vinyl chloride) (PVC), plasticized either by di(2-ethylhexyl)phthalate (DEHP) or medium molecular weight polyesterurethane (PESTUR) or by both plasticizers, was studied by isoconversionalmethods on the basis of thermogravimetric data under dynamic heating conditions. It has been found that the initial decomposition temperature is higher for PVC plasticized with PESTUR in comparison with PVC plasticized with DEHP or with PESTUR/DEHP, and thermal degradation shows features of multistep complex process. Application of polymeric plasticizer leads to the increase in values and a "smoothing" effect in the course of energy of activation and pre-exponential factor at initial stage of decomposition indicating thus the hindered migration of medium molecular weight compound from PVC matrix (in comparison with PVC containing monomeric DEHP) due to steric hindrances as well as due to specific interactions between C=O and Cl groups along the macrochains.