Soft and hard sections from cellulose-reinforced poly(lactic acid)-based food packaging films: A critical review

The cellulose-reinforced poly(lactic acid) (PLA)-based films have been of great interest for use as food packaging material. However, the semicrystalline behavior of both biobased hydric polymers has not been taken into account in many investigations studying the mechanical, thermal, antimicrobial and barrier properties, as well as the biodegradability and compostability in these composite materials. A critical analysis of the existing literature in this field, highlighting mainly the studies made during the last five years in terms of crystalline and amorphous regions, 'soft' and 'hard' sections, as well as the blend of these immiscible polymers is shown in this review. The perspectives of future work that should be done to solve the many existing concerns have also been suggested in this review. We can indicate from the papers analyzed that the new trends in the development of these materials as food packaging will be focused on shape memory, pH-sensitive and active films to maintain the food shelf-life, and achieve non-adulteration of them, as well as having food packaging materials more convenient for today's society.