Preparation and Characterization of Polyester Based on bis- (2- hydroxypropyl terephthalate)

Abstract

Polyester based on bis- (2-hydroxypropyl terephthalate) (BHPT) and maleic anhydride (MA) was prepared and its structure confirmed by spectral analysis. The kinetic of the condensation reaction was investigated at three different temperatures (180–200 °C) in the presence and the absence of p-toluene sulphonic acid (PTSA) as a catalyst. The reaction order was found to be second and third order in the presence and absence of the catalyst, respectively. The activation energy was calculated in both cases and was found to be 15.7 and 145.5 kJ mol−1 in the presence and absence of the catalyst, respectively. The polyester was mixed with styrene monomer, and with methyl ethyl ketone peroxide (0.5 wt.%) as initiator and cobalt naphthenate (0.25 wt.%) as accelerator to obtain a styrenated resin with good mechanical properties. N-phenyl maleimide (NPMI) was also used together with styrene in different ratios to form a copolymer. No pronounced improvement in the mechanical and the thermal properties was found after the introduction of NPMI.