Reinforcement of Refined and Semi-Refined Carrageenan Film with Nanocellulose.

Carrageenans obtained from seaweeds can be processed into films for a range of applications including food packaging. The level of carrageenan refinement during extraction can influence the key properties, with semi-refined carrageenan (SRC) containing more impurities than the more refined carrageenan (RC). Further refinement steps, however, result in higher costs associated with the production of RC. In order to obtain a lower cost and more ecofriendly, bio-based material for food packaging applications, SRC was used in this investigation to produce a thin film reinforced with nanocellulose fibrils (NCF). Films derived from RC containing NCF were also investigated with water sensitivity and physico-mechanical and thermal properties among the properties tested. Levels of NCF were varied from 1% to 7% (w/w), and in general, the NCF reinforcement improved the overall properties of both the SRC and RC films, including the water sensitivity and moisture barrier. However, NCF inclusion in SRC film was less effective with regard to the mechanical and thermal properties compared with NCF inclusion in RC film. The enhancement in properties was attributed to the greater cohesiveness of the reinforced polymer structure and the crystalline regions formed in the structures of SRC and RC films by NCF incorporation.

A Review of Property Enhancement Techniques for Carrageenan-based Films and Coatings.

Carrageenan, a polysaccharide extracted from marine algae, is becoming increasingly regarded as a promising renewable biomaterial that has strong potential as a substitute for conventional synthetic plastics. Materials derived from carrageenans have been widely investigated over the recent decades for use in pharmaceutical and biomedical applications through to edible films and coatings. In the area of flexible films, carrageenans suffer from limitations that are primarily a result of their inherent hydrophilicity. Considerable research efforts have been devoted to the improvement of the properties of carrageenan films in order to extend the range of suitable applications. These include blending with other polymers, the use of plasticizers, and reinforcements with nanomaterials. This review comprehensively assesses the current status of carrageenan-based film development including material characteristics and strategies to obtain desirable film properties with particular regard to real applications.