Effect of 4,4'-methylenediphenyl diisocyanate on thermal and mechanical properties of Bioflex/lactic acid polycondensate blends

Abstract

Polylactic acid as thermoplastic aliphatic polyester has attracted much attention because of its renewability and biodegradability. The current work investigates the influence of 4,4'-methylenediphenyl diisocyanate (MDI) on thermal and mechanical properties of Bioflex/lactic acid polycondensate blends. Bioflex is a commercial product based on polylactic acid and a thermoplastic copolyester. Lactic acid polycondensate (polylactide) was obtained by direct melt polycondensation of lactic acid in the presence of stannous octoate as the catalyst. The increase in molecular weights (size exclusion chromatography) and the improved mechanical properties (stress-strain analysis) revealed that MDI under reactive extrusion conditions effectively adjusted the compatibility of Bioflex with 10 wt% of polylactide.