In the present investigation, a compatibilized blend of thermoplastic polyurethane (TPU) and polydimethylsiloxane (PDMS) is prepared by using copolymer of ethylene and methyl acrylate (EMA) as a reactive compatibilizer. Detailed in vitro biocompatibility studies were carried out for this compatibilized blend and the material was found noncytotoxic towards L929 mouse fibroblast subcutaneous connective tissue cell line. Microporosity was created on the surface of membranes prepared from the blend material by adopting the crazing mechanism. Cell proliferation and growth studies on the membranes surface showed that the microporous surface favoured ingrowth of the cells compared with a nonmicroporous surface. Suture holding strength studies indicate that the microporous membranes have enough strength to withstand the cutting and tearing forces through the suture hole. This blend material could be evaluated further to find its suitability in various implant applications. 1. Introduction Thermoplastic polyurethane (TPU) and polydimethylsiloxane rubber (PDMS) are two well known biomaterials with excellent biocompatibility and biostability. A large volume of literature resources are available describing the biomedical applications of these two materials [1–6]. If TPU and PDMS are blended together, the mechanical strength and biocompatibility of TPU can be added to the inertness and biocompatibility of PDMS. The resulting blend material has several advantages. One of the main advantages is the formation of a thermoplastic elastomer material, which has the properties of an elastomer at room temperature and allows processing in conventional plastic processing equipments like injection moulding machine or an extruder. Furthermore, it allows tailoring of the end use property requirements by adjusting the ratio of the blend components. Being a thermoplastic elastomer material, the need for crosslinking the PDMS component can be avoided, which is a major gain. This is because crosslinking involves the use of various curing chemicals and there is a chance for migration of these chemicals to the surrounding tissues during the long term implantation period of the material, which will result in toxicity for the surrounding tissues and results in the rejection of the implant from the body [7]. The main obstacle in blending TPU with PDMS is the formation of an immiscible blend which will lead to phase separation. This can be addressed by adopting the reactive blending or in situ compatibilization technique using a copolymer capable of making specific interactions with the
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