Abstract
Bone cements prepared with either tetrahydrofurfuryl methacrylate (THFMA) or butyl methacrylate (BMA) and poly(ethyl methacrylate) (PEMA) were characterized after being stored in a dessicator at 30 °C for 1 year by thermal, spectroscopic and mechanical techniques. Differential scanning calorimetry (DSC) revealed evidence of annealing during storage and the presence of a single glass transition temperature (Tg). Annealing occurred to a greater extent in THFMA bone cement, but mechanical testing demonstrated that they also behaved as low modulus matrices compared to PALACOS®. The presence of small amounts of residual monomer (quantified by 1H-NMR) did not affect either their mechanical properties or their Tg. Dynamic mechanical thermal analysis (DMTA) also revealed a single Tg, which was higher than the Tg obtained by DSC. Secondary transitions were also observed, but they were not affected by the frequency in the range from 0.1–30 Hz. However, dielectric thermal analysis (DETA) measurements showed that secondary transitions appeared above 100 Hz. Solution and solid-state 13C NMR spectra of THFMA-PEMA showed that the tetrahydrofuranic (THF) ring is not cleavaged during polymerization.