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This study examines the possibility of replacing partially or totally the di(2-ethylhexyl) phthalate (DEHP -low molecular plasticizer) from the poly(vinyl chloride) (PVC) compositions intended for medical devices, with poly("-caprolactone) (PCL -biodegradable, biocompatible, and macromolecular plasticizer). Nine different plasticized PVC (PVC-P) compositions are analyzed from the viewpoint of thermal and mechanical properties, plasticizer loss, and extraction behavior in different medical media. After comparing the experimental results with the data from the literature, corresponding to traditional PVC-P, it can be concluded that the PCL and even PCL-DEHP mixture behave as better plasticizers for PVC, providing a lower extraction risk and similar or even improved thermal and mechanical properties.KEY WORDS: poly(vinyl chloride) (PVC), plasticizers, poly("-caprolactone) (PCL), plasticizer loss, extraction behavior in different medical media.

Thermal properties—such as thermal conductivity, thermal diffusivity, and specific heat—of metal (copper, zinc, iron, and bronze) powder-filled high-density polyethylene composites are investigated experimentally in the range of filler content 0-24% by volume. Experimental results show a region of low particle content, 0-16% by volume, where the particles are distributed homogeneously in the polymer matrix and do not interact with each other. In this region most of the thermal conductivity models for two-phase systems are applicable. At higher particle content, the filler tends to form agglomerates and conductive chains resulting in a rapid increase in thermal conductivity.

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Bromine-containing methacrylate, 2-(2-bromoisobutyryloxy) ethyl methacrylate (BIEM), had been used in the formulation of acrylic radiopaque cements. The effect of this monomer incorporated into the liquid phase of acrylic bone cement (ABC), on the curing parameters, thermal properties, water absorption, density, compression tests and radiopacity was studied. A decrease of maximum temperature and an increase of the setting time were observed with the addition of the brominecontaining monomer in the radiolucent cement composition. Adding BIEM in radiolucent ABCs composition results in the decrease of glass transition temperature and increase in its thermal stability. The ABCs modified with bromine-containing comonomer are characterized by polymerization shrinkage lower than the radiolucent cement. Addition of bromine-containing comonomer in radiolucent ABC composition determines the increase of compressive strength. The ABCs modified with brominecontaining comonomer proved to be radiopaque.