Synthesis and Degradation of Poly (Diol Citric Itaconate) Polyester Elastomers

Synthetic bioelastomers are a class of biomaterials that are extensively used for biomedical applications. A potential biomaterial is expected to be elastic and flexible, so that it could mimic the mechanical properties of natural tissues. In this paper, we report the studies on two elastomers: Poly(1,12-dodecanediol citrate-co-1,12-dodecanediol itaconate) [p(DDCI)] and Poly(1,4-cyclohexanedimethanol citrate-co-1,4-cyclohexanedimethanol itaconate) [p(CHCI)], containing multifunctional non-toxic monomers; citric acid (CA), 1,12-dodecanediol (DD), 1,4- cyclohexanedimethanol (CHDM) and itaconic acid (IA). Citric acid can undergo polycondensation in the absence of toxic catalyst. Also, its multifunctionality favours crosslinking of polymeric networks during thermal curing conditions. The polyester was characterized by Fourier transform infrared spectroscopy, ¹H NMR spectroscopy and differential scanning calorimetry analysis. The Young's modulus, UTS, % elongation and swelling experiments revealed that the mechanical and swelling characteristics of the polyesters revealed that it is can be fabricated as per the requirements of its biological applications. The solubility tests revealed that the pre-polymers were soluble in common organic solvents therefore facilitating processing ability for scaffold fabrication. The insolubility of postpolymerised polyester confirmed their elastomeric nature and was further evidenced by the glass transition temperature which was well below the body temperature. In vitro degradation studies were performed on the polyester samples. It was observed that the Young's modulus and crosslink density were higher for [p(DDCI)] while the degradation rates of [p(CHCI)] was higher. This was attributed to the structural difference between the two diols and the degree of crosslinking between polymeric chains. As all the monomers used in the material have previously been utilized in other biomaterials the synthesized elastomer were expected to be excellent candidates as future biomaterials.