Synthesis, Structure and Properties of New Tung Oil−Styrene−Divinylbenzene Copolymers Prepared by Thermal Polymerization

Abstract

A variety of new polymers ranging from rubbery materials to tough and rigid plastics have been prepared by the thermal copolymerization of tung oil, styrene, and divinylbenzene. The thermal copolymerization is performed in the temperature range of 85-160 degrees C with variations in the stoichiometry, oxygen uptake, peroxides, and metallic catalysts used. Gelation of the reactants typically occurs at temperatures higher than 140 degrees C, and fully cured thermosets are obtained after post-curing at 160 degrees C. The fully cured thermosets are determined by Soxhlet extraction to contain approximately 90-100% cross-linked materials, and (1)H NMR and FTIR spectroscopy indicates that the cross-linked materials are random copolymers. The new bulk polymeric materials obtained are light yellow and transparent with glossy surfaces, and possess glass transition temperatures of -2 to +116 degrees C, cross-link densities of 1.0 x 10(3)-2.5 x 10(4) mol/m(3), coefficients of linear thermal expansion of 2.3 x 10(-4)-4.4 x 10(-4) per degrees C, compressive moduli of 0.02-1.12 GPa, and compressive strengths of 8-144 MPa. These materials are thermally stable below 300 degrees C and exhibit a major thermal degradation with a maximum degradation rate at 493-506 degrees C.