Characteristics of biodegradable polylactide/gelatinized starch films: Effects of starch, plasticizer, and compatibilizer

Polylactide (PLA) blends with 0–40 wt % gelatinized starches (GSs) in the presence of plasticizers and compatibilizer for improving interfacial bonding between two phases were prepared. The effects of compatibilizer, type and amount of starch, including type and concentration of plasticizer on the physical, morphological, thermal, and mechanical properties of these films were investigated. Two types of starch (corn and tapioca) were added as fillers, whereas the glycerol amount was varied from 0 to 35 wt % based on starch content. Polyethylene glycol (PEG400) and propylene glycol (PG) were added as plasticizers at four different amounts (5–20 wt %) based on PLA content, while methylenediphenyl diisocyanate was used as a compatibilizer at 1.25 wt % of GS. The results indicated that the presence of glycerol had no effect on the thermal degradation of GS. For PLA plasticization, the plasticized PLA with PEG400 had better properties than that with PG. Water absorption isotherm of the blend films increased as the amount of starches increased; in contrast, the tensile properties decreased progressively with the addition of the GS content. The blend films with gelatinized corn starch had higher tensile properties than those with gelatinized tapioca starch.