MOSIEWICKI mirna Alejandra
congresos y reuniones científicas
Resins, Foams and Shape Memory Copolymers from Vegetable Oils and Oleochemicals
F. ALTUNA; C. MEIORIN; D. MARIN; J. P.ESPINOSA; M. A. MOSIEWICKI; R. RUSECKAITE; M. I. ARANGUEN; P. M. STEFANI
Simposio; Third International Symposium. Frontiers in Polymer Science; 2013
The aim of this work is to present our current work on vegetable oil - based resins, foams and shape memory copolymers. Thermal, mechanical and optical properties of epoxy resins synthesized by the partial replacement of the synthetic diglycidyl ether of bisphenol A (DGEBA) with increasing amounts of epoxidized soybean oil (ESO) using a cycloaliphatic anhydride as a cross-linking agent and 1-methyl imidazole as an initiator were investigated. The combination of DGEBA with 40 wt % ESO resulted in a resin with significant improvement in the impact strength (38% higher than the neat DGEBA) accompanied by a small reduction of the glass transition temperature, Tg (from 120ªC to 109ºC) a reduction of about 11ºC in Tg value and without a loss in transparency and with additional benefit of being more environmentally sound than neat synthetic epoxy resins. Current work is undertaken in order to synthesize triacylglycerides containing sterically accessible terminal epoxy functionalities which are far more reactive than the internal epoxy groups in ESO. DGEBA/ESO formulations were used to produce syntactic foams. Formulation with 60%ESO and 55% (volume) of glass microballons gave rise to foams with comparable compression and thermal properties than those of the 100% synthetic counterpart. Some selected properties of shape memory copolymers obtained by cationic copolymerization of tung oil with styrene were also studied. Tg values were close to room temperature for all the copolymers, and values increased with styrene content as well as occurred with the modulus. These hard elastomers presented shape memory behavior with high recovery and fixity ratios, as well as high damping quality (damping factors 0.4 and 1.38 at 28.9 and 43.3 °C, for the tung oil homopolymer and the copolymer with 70 wt% styrene, respectively), opening possibilities for practical applications that require material response close to room temperature.