Synthesis and characterization of shape memory polyurethane with polycaprolactone/polyethylene glycol as soft segment
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Date
2019-05
Authors
Yap Saw Yin
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Abstract
The performance of the shape memory polyurethane (SMPU) elastomer depends on its chemical structure, chemical composition, crystallinity of soft segment polyol and degree of phase separation. This paper reports on the effect of molar ratio of (Palm Kernel Oil) PKO on (Polycaprolactone diol) PCL based polyurethanes and PCL-(polyethylene glycol) PEG based polyurethane. In this research, the molar ratio of PKO and types of polyol were used as manipulated variables. The SMPUs were synthesized using polycaprolactone diol, polyethylene glycol and PKO as soft segment, 4,4 methylene-bis(cyclohexyl isocyanate) (HMDI), isophorone diisocyanate (IPDI) and1,4-butanediol as the hard segment with dibutyltin dilaurate as catalyst. The SMPUs were synthesized via two-step bulk polymerization method. Several testing are performed to investigate their properties included shape memory testing, tensile testing, X-Ray Diffraction (XRD), Differential Scanning Calorimetric (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Thermal Gravimetric Analysis (TGA) and Scanning Electron Microscope (SEM). The results showed that the increased of crystallinity of soft segment enhanced the degree of phase separation, mechanical properties and shape fixity of SMPUs synthesized at the same hard segment content (40%). The results also showed that the increased of hard segment content caused the decrement of crystallinity of SMPUs soft segments and shape fixity of SMPUs. In overall, PKO20HS40 demonstrated higher modulus value, tensile strength, elongation at break and shape fixity for the PCL-based polyurethane. 100 IPDI showed higher Young’s Modulus, higher elongation at break and higher shape fixity than 100 HMDI. Both samples with combination of HMDI and IPDI polyurethanes showed much higher value of Young’s Modulus and tensile strength than 100 HMDI polyurethane and 100 IPDI polyurethane. On the other hand, PKO20PEG30 showed higher modulus value, tensile strength and shape fixity for PCL-PEG based polyurethane. With the addition of PEG, the polyurethane exhibited better mechanical properties.