Synthesis and Characterisation of Castor Oil Based Polyurethane (PU) and Its Composites

Tan, Fung Nian (2019) Synthesis and Characterisation of Castor Oil Based Polyurethane (PU) and Its Composites. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

In this project, polyurethane, PU is synthesized by using prepolymer method in which the poly(tetrahydrofuran), poly(THF) reacts with 4,4-methylenediphenyl diisocyanate , MDI to produce a prepolymer following by the addition of chain extender, butane-1,4-diol, BD. 30% castor oil based PU (PUCO3) is synthesized by replacing 30% of poly(THF) with castor oil. Calcium carbonate, CaCO3 and kaolin modified by potassium acetate (KAA) were incorporated into 30% castor oil based PU as fillers by blending and synthesis methods. From results obtained, PUCO3 have improved the glass transition temperature and tensile strength compared to pristine PU because the high degree of unsaturation of castor oil will form the affinity network in the PU structure. CaCO3 does not showed significant changes in the thermal stability and mechanical properties of the PUCO3 due to the in-homogeneous distribution of CaCO3 in PU matrix. For KAA, both blending method and synthesis method have increased the glass transition temperature and percent of elongation while incorporation of KAA by blending method have increased the tensile strength of PU film, this is due to the high speed of stirring in blending method caused the size of KAA become smaller and easily go into gaps between PU chains. The heat applied during synthesis method may help the KAA filled up the spaces between PU chains effectively, thus it increased the glass transition temperature of PU matrix due to the restriction of mobility of PU chains. According to the overall results, 0.03 wt% of KAA is the optimal amount added because it showed significant changes in glass transition temperature, tensile strength and percent of elongation, respectively.