Thiophosphate esters of cashew nutshell liquid derivatives as new antioxidants for poly(methyl methacrylate)

Abstract

In this work, poly(methyl methacrylate) films 1% additivated with new thiophosphate esters antioxidants derived from technical Cashew Nutshell Liquid (CNSL), a byproduct of the cashew nut (Anacardium occidentale L.) industry, were investigated by thermogravimetry (TG/DTG) and differential scanning calorimetry (DSC) measurements under inert (N2) and oxidative (synthetic air) atmospheres. Three new products were synthesized and characterized by GC/MS, 1H and 31P NMR. The analyses were focused on the onset (T e) and offset temperature (T o) of degradation of the films, and on the maximum degradation temperature (T MAX). It was observed that the thermal stability of the films increased with the addition of the thiophosphate ester antioxidants, which indicates that CNSL could be used as a natural source of phenolic material for the synthesis of antioxidants.