Abstract:

Objective · To investigate the mechanical properties of polyurethane composite containing polyphosphazene nanospheres. Methods · Test specimens were prepared with different materials, including polyurethane (the PU group), polyurethane containing 1% polyphosphazene nanospheres (the 1% PSZ group), polyurethane containing 5% polyphosphazene nanospheres (the 5% PSZ group), and self-curing silicone rubber soft liner material Sofreliner (the Sofreliner group). The microstructure of test specimens was observed using the scanning electron microscope (SEM). The tensile strength and tearing strength of test specimens were calculated after 0, 1 000, and 3 000 hot and cold cycles. Results · SEM observation showed that there were no nanoparticles aggregating on the surface of test specimens in the 1% PSZ and 5% PSZ groups. Depressions on the surface of test specimens were shallower in the 5% PSZ group than those in the 1% PSZ and PU groups. Before hot and cold cycling tests, the differences in tensile strength and tearing strength among the PU, 1% PSZ and 5% PSZ groups were not statistically significant, but tensile strength and tearing strength were significantly higher in the PU, 1% PSZ and 5% PSZ groups than those in the Sofreliner group (P<0.05). After hot and cold cycling tests, the tensile strength in the PU, 1% PSZ and 5% PSZ groups was slightly decreased, while the tearing strength was not significantly changed. Conclusion · The tensile strength and tearing strength of polyurethane composite are higher than those of Sofreliner and meet the clinical application standard. The surface properties of materials were improved by adding 5% polyphosphazene nanospheres to polyurethane compared with adding 1% polyphosphazene nanospheres, but the tensile strength and tearing strength were not significantly improved.

Key words: polyphosphazenes, polyurethane, mechanical properties, soft liner material