Thermal properties of poly(methyl methacrylate-co-butylacrylate-co-acrylic acid) modified with divinyl benzene and vinyltrimethoxysilane

The effect of butyl acrylate (BA), divinyl benzene (DVB) and vinyltrimethoxysilane (TMVS) on the thermal properties of poly(methyl methacrylate-co-butyl acrylate-co-acrylic acid) was investigated. Glass transition temperature (T-g), melting temperature (T-m) and specific heat capacity of the copolymers were investigated using Differential Scanning Calorimetry. Thermal stability of the copolymers which is associated with the degradation temperature (T-d) was studied by Thermogravimetric Analysis. Polyacrylates with T-g ranges between -19 degrees Cand 19 degrees C were obtained. With the incorporation of >7 wt% of DVB, the T-g of the copolymer increases from about -17 degrees C to -10 degrees C even though they have not undergone UV irradiation. Gel content results prove that crosslinking has occurred in the copolymers. With increasing amount of TMVS from 0 wt% to 7 wt%, the T-m of the copolymers prepared at acidic pH is about 40-60 degrees C higher than that at the alkaline pH. However, the addition of TMVS gives no significant effect to the T-g and T-d of the copolymer films. The thermal stability of the copolymer has improved with increasing amount of BA and DVB, with DVB being more effective. The highest T-d of 425 degrees C with 8% of DVB has been obtained. Consequently, a polyacrylate copolymer with a T-g of about -13 degrees C, a T-m of 170 degrees C and a T-d of about 424 degrees C has been successfully synthesized. Hence, the soft polyacrylate with its relatively high T-m and T-d could serve as a superb material especially to be applied in the areas that require high melting temperature and good thermal stability.