Design and optimization of biocompatible thermoplastic elastomers to compound for the manufacturing of medical devices

Abstract

In the last century, plastics changed habits, quality of life and industry. In biomedical sector, the introduction of low-cost and safe for human’s health polymers with a large range of mechanical and chemical properties, gave the possibility to create new biomedical devices. Single-use devices have seen a rapid evolution, from glass-based to thermoset and thermoplastic. Today Polyvinyl Chloride (PVC) represent around 15.2% of the medical plastics market. Unfortunately, PVC compounds have several defects, such as need of different additives to tune the mechanical properties, concern about human health, unsuitable for some specific applications and interaction of PVC with drugs. To overcome this problems, new thermoplastic compounds and blends have been developed to replace PVC compounds, such as thermoplastic elastomers (TPE). The industrial research focused mainly to TPEs and TPO due to their low cost, wide range of both mechanical and chemical properties, and biocompatibility, being in every case a trade-off between desired properties and drawbacks. For example TPEs and TPO cannot be sterilized by steam or autoclave methods, SEBS cannot be glued with Cyclohexanone solvent, TPEs are difficult to print with injection molding, TPO tend to stick in the molds and have low crystallization The developed compounds need also to be transparent, no colored and weldable with radiofrequency welding technique. The present research work focused on the production of new TPE compounds characterized by low hardness, good elongation at break, adequate thermal resistance, good transparency, biocompatibility, and capability to be manufactured with most used technics in biomedical field, in order to replace PVC compounds. Various TPE matrices were considered, and the best ones modified with additives of various nature. All developed compounds have been characterized from optical, thermal and mechanical point of view. Further analyses have been conducted and processing parameters were investigated, to achieve the scale-up of production