Synthesis and Characterization of Block Copolymer from Natural Rubber, Toluene-2,4-Diisocyanate and Poly(ξ-aprolactone) Diol-Based Polyurethane

A new type of polyurethane (PU) has been synthesized by using hydroxyl terminated liquid natural rubber (HTNR) and poly(e-caprolactone) (PCL) as a soft segment and toluene-2,4 diisocyanate (TDI) as a hard segment. This PU becomes a biodegradable and recyclable polymer. The PU samples were synthesized by solution polymerization. TDI/PCL polymerization was prepared in order to determine the appropriate NCO:OH ratio which evaluated from the molecular weight of derived PU and the ratios which were able to form a polymeric film. The suitable NCO:OH ratios were 0.84:1 – 1.20:1 and the Mn of the derived PUs was 3000-5500 g/mol determined by using GPC. PU from PCL-HTNR block copolymer was synthesized by varying molar ratio between PCL and HTNR. HTNR has been synthesized by epoxidation reaction and chain cleavage of natural rubber. The Mn of HTNR was in the range of 1700-8000 g/mol. 1H-NMR and FTIR were used to determine the functional group in order to verify the prepared HTNR and PU. Glass transition temperature and thermal decomposition of PU samples were investigated by using DSC and TGA, respectively.