Study On Structure And Properties Of Xylitol-based Bioelatomers

In this paper, the two-step melt polycondensation method (prepolymerization and curing) was utilized to prepare PXS and PXO bioelastomer by using xylitol, sebacic acid and suberic acid. The nano-hydroxyapatite(n-HA), which is one of the components of human bone tissue with good biocompatibility, was used to fabricate the PXS/n-HA nanocomposites by is-situ polycondensation method to enhance the mechanical properties of the elastomer furtherly.FTIR, DSC, XRD and other measurements were used to characterize and investigate the structure and properties of bioelastomer. PXS and PXO are all composed of sol and gel, and the elastomer exhibited some ordered structure. With the increase of diacid in the reaction, the elastomer has crystallized structure. DSC results indicated that the glass transition temperatures (Tg) of these material are all below room temperature, which insure the elastomer has high-elastic properties at body temperature. The more diacid in the reaction, the lower Tg was observed. The mechanical properties resulsts indicted that the tensile strengths of PXO and PXS were 0.16-1.72MPa and 0.24-3.22MPa respectively, and the elongations at break of PXO and PXS are 166-212% and 47-251% respectively for different momoer ratios. At the same monomer molar ratio, PXS exhibited better mechanical strength than PXO. The elastomers were both biodegradable and the degredation rate could be controlled by altering the monomer ratios. In addition, the material had good stability in the water enviroment due to its low water absorption.The mechanical property of PXS/n-HA nanocomposites demonstrated higher tensile strength and elongation at break. The tensile strength of PXS/n-HA nanocomposites is increased from 0.16-1.72MPa to 0.77-3.48 MPa and 0.5 to 2 times than PXS, and the elongation at break increased form 47-251% to 166-885% and 2 to 2.5 times than PXS. Also, it showed that the smaller particle size of n-HA, the higher mechanical properties of the elastomers. Micromophology indicated that the n-HA was fairly dispersed in elastomers except some conglomeration. The better dispersion could cause the higher mechanical properties. The PXS/n-HA nanocomposites had slower degradation rate compared with the PXS. In briefly, the elastomers had great potential to be used into tissue engineering area due to its good mechanical properties and biodegradation.