Effect of compounding approaches on fiber dispersion and performance of poly(lactic acid)/cellulose nanocrystal composite blown films

This study was aimed to identify the best approach for incorporating cellulose nanocrystals (CNCs) into a poly(lactic acid) (PLA) matrix by examining two different CNC addition approaches. The first approach consisted of melt blending PLA and CNCs in a three-piece internal mixer whereas the second method involved the direct dry mixing of PLA and CNCs. The prepared compounded materials were then blown into films and compared in terms of fiber dispersion, optical, thermal and barrier properties. The experimental results indicated that the extent of fiber dispersion was not influenced by the CNC addition method, i.e., good dispersion was achieved by either method. However, the melt blended PLA/CNC films thermomechanically degraded during the melt blending process. Consequently, the melt blended PLA/CNC films had inferior properties than their direct dry blended counterparts. Thus, the direct dry blending process appeared to be the best approach for incorporating CNCs into the PLA matrix.