Polylactic acid reinforced with nanocellulose: current applications and future trends

In recent years renewed interest on the development of biopolymers, based on constituents obtained from natural resources is gaining much attention. Reinforced biopolymer with natural fibres is the future of ‘‘green composites’’ addressing many sustainability issues. Among the available biopolymer, Polylactic acid (PLA) is the only natural resource polymer produced at a large scale of over 140,000 tonnes per year. PLA is a biodegradable thermoplastic aliphatic polyester derived from renewable resources, such as corn starch (in the United States and Canada), tapioca roots, chips or starch (mostly in Asia), or sugarcane (in the rest of the world). In 2010, PLA had the second highest consumption volume of any bioplastic of the world. Natural fibre reinforced PLA based biocomposites are widely investigated by the polymer scientists in the last decade to compete with non renewable petroleum based products. The type of fibre used plays an important role in fibre/matrix adhesion and thereby affects the mechanical performance of the biocomposites. For the processing of polymer nanocomposites, cellulose nanoparticles are an ideal candidate, because of their mechanical properties, reinforcing capabilities, abundance, low density, and biodegradability. Cellulose is probably the most used and well-known renewable and sustainable raw materialA comprehensive and exhaustive review was carried out based on the combination of nanocellulose with PLA to produce nanocomposite materials. The processing conditions to obtain the nanoscale materials are summarized and discussed. The main advantages and limitations of these nanomaterials are addressed. The addition of cellulose nanocrystals (CNC) to the biopolymers such as PLA, is pioneer of a new potential to create innovative bio-nanocomposite materials with improved properties and performance. However, safety issues of nanocellulose should be precisely monitored and controlled in order to confirm whether it has no harmful effects on human´s health and on environment.N/