Influence of Vitamin C on Morphological and Thermal Behaviour of Biomedical UHMWPE

Summary Biomedical Ultra-High-Molecular-Weight Polyethylene (B-UHMWPE) is widely used in orthopaedics as a biomaterial because of its mechanical properties and biocompatibility. However the adding of vitamin antioxidants can influence the inflammatory process. Thus, the objective of this study is to evaluate the influence of adding ascorbic acid (vitamin C) at different concentrations to the B-UHMWPE matrix, using for this purpose the Scanning Electron Microscopy (SEM) and Differential Scanning Calorimetry (DSC) analyses. The vitamin C was mixed with B-UHMWPE in concentrations of 0.5, 1.0 and 2.0%wt and the molding was performed with a 10MPa load at 160 °C for 6min.The fracture surface of cross-sectional area of B-UHMWPE modified with vitamin C showed that the vitamin is present in the polymer matrix in the form of small agglomerates, being an indication that there was no fusion of the vitamin C during the processing step. Using the technique of differential scanning calorimetry it was observed that the melting temperature remained constant as well as the crystallisation temperature, but there was a small variation in crystallinity with the addition of vitamin C. From this study, we conclude that the presence of vitamin C (ascorbic acid) did not alter the thermal properties of crystallisation and melting of B-UHMWPE.