Simultaneous interpenetrating networks based on castor oil elastorners and polystyrene. IV. Stress‐strain and impact loading behavior

The stress‐strain and impact loading behavior of simultaneous interpenetrating networks (SIN's) based on three elastomers derived from polymerized castor oil and polystyrene was studied. The elastomers included the sebacic acid polyester, the 2,4‐tolylene diisocyanate (TDI) polyurethane, and the mixed sebacic acid‐TDI poly(ester‐urethane). Both toughened plastic and reinforced elastomer compositions were prepared. Stress‐strain measurements and Izod impact studies were carried out at room temperature. Both the plastic and the elastomeric SIN's proved tougher than their corrresponding homopolymer networks. Elongations to break of about 8 to 16 percent were found for the plastics, while the elastomers ranged from 55 to 125 percent. The castor oil polyester elastomer toughened plastic yielded the greatest improvement in impact resistance, having a value of 68 J/m.