PLA Composites and Fibers

which is more hydrophobic than PLA, was blended with PLA by Siparsky et al. [25] to achieve and enhance hydrophobicity. PLA homopolymer and blends were exposed to various temperatures and relative humidities, and WVP of the blends were found to be higher than those of neat PLA. 

Chitosan is a water-insoluble, nontoxic, edible, biodegradable polymer (polysaccharide) that is obtained commercially from chitin by alkaline deacetylation [103]. Chitosan is the second most abundant biopolymer in nature after cellulose. Since chitosan is a polycationic polymer, its high sensitivity to moisture limits its applications. One way to overcome this drawback is to blend the material with humidity resistant polymers such has PLA. Suyatma et al. [104] combined hydrophilic chitosan with hydrophobic PLA (92% L-lactide and 8% mesolactide, Mw = 49,000 Da) by solution and film mixing, resulting in improved water barrier properties and decreased water sensitivity of the chitosan films. However, testing of mechanical and thermal properties revealed that chitosan and PLA blends are incompatible. 

PHB is accumulated by a large number of bacteria as an energy and carbon reserve. PHB is a biodegradable and biocompostable highly crystalline thermoplastic with very low water vapor permeability, similar to that of LDPE [105]. PLA/PHB blends have been studied with the goal of producing PLA-based materials with different physical properties and improved processability [106]. 

The use of inert fillers in polymers can either increase or decrease barrier properties, depending on the degree of compatibility and adhesion between the filler and the polymer matrix [40]. Additives such as plasticizers, impact modifiers, and other monomeric and polymeric additives 

PERMEATION, SORPTION, AND DIFFUSION IN POLY(LACTIC ACID) 

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