Compatibilization of PLA grafted maleic anhydrate through blending of thermoplastic starch (TPS) and nanoclay nanocomposites for the reduction of gas permeability

Abstract

Here, the effects of compatibilization and clay nanoparticles on the gas permeability of nanocomposites of poly-lactic acid (PLA)/thermoplastic starch (TPS)/nanoclay were discussed. TPS and compatibilized PLA/TPS were tailored in the first step. The starch with D-sorbitol as a plasticizer was mingled through the internal mixer. Afterward, the maleination method was utilized on PLA to ameliorate the compatibilization of PLA and TPS. In this regard, maleic anhydrate (MA) has been grafted on PLA in the presence of L101 as a peroxide initiator via melt mixing to obtain PLA-g-MA. The optimum content of PLA-g-MA was about 4 phr, confirmed by DMTA and SEM. Noteworthy, the presence of PLA-g-MA has moderately improved the oxygen barrier. Then, the nanocomposites of PLA and TPS containing 1% of Cloisite-30B as well as the optimum compatibilizer (4phr), were produced by melt mixing in the masterbatch module leading to the formation of an extraordinary well-dispersed structure according to XRD patterns. The mixing order controlled the localization of nanosheets. It was concluded that the inclusion of 1% nanoclay in the PLA phase reduces the oxygen permeability by 55% compared to the pristine blend due to the tortuosity effect of nanosheets that are appropriately dispersed in the matrix.

Keywords

• PLA/starch blend
• polymer nanocomposite
• compatibilization procedure
• gas permeability