Development of Biodegradable Polyurethane Foam: the Effect of Chain Extenders on Properties and Biodegradation

Abstract

This research studied a synthesis of biodegradable polyurethane foam which is usually synthesized by polyaddition polymerization of difunctional isocyanates, polyols and chain extenders. Recently, the properties of PU foam are primarily depended on varying raw material. In this study, there not only synthesized biodegradable polyurethane foams with different chain extender length to improve their properties but also investigated the accelerative degradation after disposed it into environment. The chain extender structure and content ratio of polyols were varied. Hydrophobic material, Polycaprolactone (PCL) is one of widely used as a main building block of soft segment due to its crystallinity. While polypropylene glycol (PPG) as a hydrophilic material, it can enhance the hydrolytic degradation. This work is focus on the use of cheap accessible diols as the chain extender, ethylene glycol (EG), 1,4 butanediol (BDO) and 1,6 hexanediol (HDO). The urethane linkage and other functional group in PU foam was found by the FTIR spectra. With increasing of PPG content, the compressive strength and young’s modulus, density, as well as the glass transition temperature (Tg) by DSC of all PU foam become to lower. The longer chain of chain extender showed the results that the compressive strength and young’s modulus and water absorption become lower. While the Tg and density become higher. Moreover, the morphologies of cell foam after degradation was confirmed by using SEM, it was showed that the cell size increased and irregular pore characteristic when increasing PPG content up to 10% and synthesizing with HDO chain extenders.