Strengthening of immiscible polyamide 6 and isosorbide-containing copolyester blends by reactive compatibilization

Abstract

As the demand for carbon neutrality increases, interests in green polymers are increasing. Poly (ethylene glycol 1,4-cyclohexanedimethylene isosorbide terephthalate) (PEICT) is a copolyester containing isosorbide derived from biomass and has the characteristics of transparency, chemical resistance, and impact resistance. Recently, some studies have reported that PEICT is a promising blend component that can increase impact strength. Polyamide 6 (PA6) is a representative engineering plastic and is used in various fields by enhancing its impact, chemical, and weather resistance. In this study, PA6 and PEICT blends were prepared by melt processing. Blends had two glass temperatures, indicating that PA6 and PEICT were immiscible. A reactive compatibilizer with epoxy functional groups was introduced to reduce the interfacial tension of immiscible PA6 and PEICT. The compatibilizer was predicted to be located between the interfaces of the blend components. The epoxy groups of compatibilizer reacted with the terminal groups of blend components to form branched PA6-co-PEICT copolymers. The copolymers inhibited the aggregation of PEICT and improved the interfacial adhesion between PA6 and PEICT, effectively performing compatibilization. The increased compatibility enhanced the impact transfer between PA6 and PEICT, thereby improving impact strength of blends. Compatibilized PA6/PEICT (80/20) blend showed 4.9 times improved impact strength compared to pristine PA6. The introduction of reactive compatibilizer improved the impact strength and ductility of the PA6, and the improvement was discussed by chemical structural and morphological analysis.