Blends of Carboxymethyl Cellulose and Cottonseed Protein as Biodegradable Films.

With the increasing awareness of plastic pollution in the environment and the accumulation of microplastics in water, a significant amount of research and development is ongoing to replace the synthetic plastics in packaging and coatings. In this work, we explored the blends of carboxymethyl cellulose (CMC) and washed cottonseed meal (CSM, consisting mostly of cottonseed protein) as agro-based, biodegradable, and sustainable alternatives to plastics. Glycerol was found to be a suitable plasticizer for these blends. The blends of CMC/CSM were produced as single-layer films from 50 to 90 µm in thickness, consisting of different proportions of the components and plasticizer. The evaluated properties included opacity, water vapor permeability, mechanical properties, thermogravimetric analysis, moisture sorption analysis, and water swelling test. Higher percentages of CSM in the blend resulted in higher opacity and lower water vapor permeation rates. The mechanical strength waned with lower levels of CMC. Possible applications for these blends include their use as water-soluble food packaging and coatings and as dissolvable bags and pouches for detergents and agrochemicals.

Bilayer Films of Poly(lactic acid) and Cottonseed Protein for Packaging Applications.

Poly(lactic acid) (PLA) is a common biobased film-former made from renewable biomass, such as polysaccharides from sugarcane, corn, or cassava. It has good physical properties but is relatively expensive when compared to the plastics used for food packaging. In this work, bilayer films were designed, incorporating a PLA layer and a layer of washed cottonseed meal (CSM), an inexpensive agro-based raw material from cotton manufacturing, where the main component is cottonseed protein. These bilayer films were made through the solvent casting method. The combined thickness of the PLA/CSM bilayer film was between 47 and 83 µm. The thickness of the PLA layer in this film was 10%, 30%, or 50% of the total bilayer film's thickness. Mechanical properties of the films, opacity, water vapor permeation, and thermal properties were evaluated. Since PLA and CSM are both agro-based, sustainable, and biodegradable, the bilayer film may be used as an eco-friendlier food packaging material, which helps reduce the environmental problems of plastic waste and microplastics. Moreover, the utilization of cottonseed meal may add value to this cotton byproduct and provide a potential economic benefit to cotton farmers.