Multiscale study of poly(butylene terephthalate) hydrolysis.

• Hydrolysis of PBT grades differing by initial molar mass and / or presence of pigments. • Kinetic modeling of PBT hydrolysis auto accelerated by chain ends. • Embrittlement criteria common for all PBT's marterials. This paper reports the hydrolysis of several PBT materials (pigmented or not). Degradation was monitored by gel permeation chromatography (chain scission), DSC (crystalline morphology), tensile test (residual mechanical properties) and DVS (polymer-water interaction). The embrittlement comes from chain scission associated with a small chemicrystallization effect. Results lead to the proposal of a kinetic model for the chain scission rate aimed to describe the auto-acceleration effect induced by carboxylic acids (chain ends) and successfully compared to results both from this work or literature. The mixed "average molar mass – crystallinity" criterion proposed in a previous paper was specified. At last, the effect of pigments is illustrated and shows that carbon black (present in particular in one masterbatch) plays an aggravating role on hydrolysis. [ABSTRACT FROM AUTHOR]