Highly branched and nontoxic plasticizers based on natural cashew shell oil by a facile and sustainable way

Almost 80% of plasticizers used in polyvinyl chloride (PVC) materials are toxic o-phenyl plasticizers. In order to replace o-phenyl plasticizers in PVC materials, a series of highly branched and nontoxic plasticizers (CHE-4,CHE-8 and CHE-12) based on natural cashew shell oil (CNSL), an agricultural and forestry residue, were synthesized via facile one-pot solvent-free synthesis. The chemical structure, relative molecular mass and thermal stability of the obtained highly branched and nontoxic plasticizers were characterized. The toxicity of CHE-12 was investigated in the low (1000 mg/kg), middle (2000 mg/kg and 3000 mg/kg) and high dose (5000 mg/kg), the results suggested that CHE-12 has toxic doses of 5000 mg/kg and is a non-toxic plasticizer. PVC materials plasticized with CHE-12 showed more excellent thermal stability, plasticizing property and migration stability than dioctyl phthalate (DOP). Microstructure of PVC materials was investigated and the results showed that compatibility of PVC with CHE-12 is better than DOP. The microscopic plasticizing mechanism was also investigated. CHEs were proved to be promising candidates for the chemical conversion of CNSL derivatives into environmentally friendly and non-toxic plasticizers.