Tuning properties of bio-rubbers and its nanocomposites with addition of succinic acid and ɛ-caprolactone monomers to poly(glycerol sebacic acid) as main platform for application in tissue engineering

Abstract

In this research new types of biomaterials have been introduced. They are based on glycerin, sebacic acid, succinic acid and ɛ-caprolactone as their monomers. Their bio-nanocomposites were prepared with organo-montmorillonite (Cloisite 30B, C30B) and nano-hydroxyapatite (n-HA) by in-situ polymerization technique. Chemical, mechanical and biologocal properties of prepared samples were assessed by different tests. 1H NMR study showed that resin of polymeric chains poly(glycerol-sebacic) (PGSe), poly(glycerol-Sebacic-succinic) (PGSeSu) and Poly(glycerol-sebacic-succinic)-co-polycaprolactone (PGSeSuPC) were successfully synthesized. The results of dynamic contact angle test were showed that the presence of succinic acid and ɛ-caprolactone monomers in PGSe would provide attractive characteristics and the existence of nanoparticles would enhance the hydrophilicity of the samples. According to Dynamic mechanical thermal analysis (DMTA), it was determined that the storage modulus of samples which have been co-polymered by succinic acid and ɛ-caprolactone is higher than that of the PGSe at −40 °C and it is lower in higher temperatures. The existence of succinic acid and ɛ-caprolactone monomers have had softening effects on movement of PGSe chains. In tan(δ) behavior, the glass transformation temperature (Tg) for PGSe is about –7.6 °C and by co-polymerization with succinic acid and ɛ-caprolactone it changed to −11.8 °C and −26 °C respectively. Mechanical analysis on normal and degraded samples were done and their results showed that the presence of e-caprolactone into the bio-rubber’s backbone, has had significant effects on Young’s modulus and tensile strength. However, cyclic tensile test showed that hysteresis and residual strain of PGSeSuPC-C3 sample was higher than other samples. Hydrocatalytic degradation test explained that the existence of succinic acid monomer as an absorbent of water molecules, have enhanced the degradability, while the combination of nanoparticles of C30B and n-HA have had a positive influence on samples degradation.