New composites based on polylactide, nanoclay, and rubber

Three types of composites, namely, polylactide (PLA)/nanoclay, PLA/core-shell rubber, and PLA/nanoclay/rubber were melt compounded via a co-rotating twin-screw extruder. The effects of two types of organically modified montmorilloninte (MMT) nanoclay (i.e., Cloisite 30B and 20A), two types of core (polybutylacrylate)-shell (polymethylmethacrylate (PMMA)) rubber (i.e., Paraloid EXL2330 and EXL2314), and the combination of nanoclay and rubber on the mechanical properties and thermal properties of the composites were investigated. According to X-ray diffraction (XRD) analysis, both types of PLA/5 wt% nanoclay composites had intercalated morphology. In comparison with pure PLA, both types of PLA/5 wt% nanoclay composites had increased modulus, slightly reduced tensile strength, and similar impact strength. On the other hand, PLA/EXL2330 composites with a rubber loading level of 10 wt% or higher had much higher impact strength but lower modulus and strength when compared to pure PLA. Simultaneous addition of 5 wt% nanoclay (Cloisite 30B) and 20 wt% EXL2330 resulted in a PLA composite with a 134% increase in impact strength, similar modulus, and a 28% reduction in tensile strength in comparison to pure PLA. It was also found that the addition of rubber EXL2330 promoted the intercalation process.