Chemical modification of neoprene rubber by grafting cardanol, a versatile renewable materials from cashew industry

In order to plasticize neoprene rubber (CR), a natural plasticizer,derived from Cashew Nut Shell Liquid (CNSL),was covalently bound to CR at room temperature via click chemistry. That is, the covalent attachment of the cardanol-based internal plasticizer to CR matrix, is descried for the first time. The chemical structure and properties of cardanol-based internal plasticizer and internally plasticized CR materials was characterized by FTIR, dynamic mechanical analysis (DMA), plasticizer migration tests, differential scanning calorimeter (DSC), and gel permeation chromatography (GPC). Results indicated when cardanol was grafted onto CR (CR-CPE), CR-CPE had a lower Tg compared with plain CR. Self-plasticization CR samples showed zero migration in petroleum ether, but 1. 58 mg·mL⁻¹ of cardanol leached from CR/cardanol blend(CR-car) system into petroleum ether. The CR-CPE materials were expected to be commercial application in producing food packing, toys, and medical devices with high requirements in migration resistance.