Cottonseed protein bioplastics (CPBs) from cottonseed flour were successfully prepared by hot-press molding in the presence of urea, aldehydes and glycerol. The effect of cross-linking treatment on the thermal stability, water absorption resistance and mechanical strength was investigated, and found to improve all properties. Increasing glycerol concentration resulted in a decrease in denaturation and α-relaxation temperature of the cottonseed protein as well as storage modulus of the plasticised CPBs. Interestingly, the colour and odor of the CPBs before and after hot compression changed. The mechanism proposed involved urea induced protein denaturation and Maillard-driven generation of the cross-linked structure, both in thermal and alkaline processed conditions. According to Fickian diffusivity, liquid transport and liquid permeability, chemical interactions and physical transport processes are responsible for the different water transport behaviours in the CPBs and the cross-linked CPBs, respectively. These findings could provide valuable in-depth information for tailoring the properties of the environmentally sustainable CPBs, which are attractive for low-load bearing applications, such as agriculture, packing and garden amenities, etc.

Feathers, which contain >90% keratin, are valuable natural protein resources. The aim of this study is to prepare antimicrobial feather keratin (FK)-based nanofibers by incorporating silver nanoparticles (AgNPs). A series of AgNPs-embedded feather keratin/poly(vinyl alcohol)/poly(ethylene oxide) (FK/PVA/PEO) composite nanofibers with varying amounts of AgNPs content were fabricated by electrospinning. Their morphology, crystallinity, thermal stability, tensile property, and antibacterial activity were systematically investigated. The average diameters of composite nanofibers gradually decreased with increases in the amount of AgNPs. The crystallinity, thermal stability, and antibacterial activity of FK/PVA/PEO nanofibers were enhanced by embedding AgNPs. When embedded with 1.2% AgNPs, both the tensile strength and elongation-at-break reached the highest level. This work has the potential to expand the application of FK-based nanofibers in the biomaterial field.

Given the pressing climate and sustainability challenges, shifting industrial processes towards environmentally friendly practices is imperative. Among various strategies, the generation of green, flexible materials combined with efficient reutilization of biomass stands out. This review provides a comprehensive analysis of the hydrothermal carbonization (HTC) process as a sustainable approach for developing carbonaceous materials from biomass. Key parameters influencing hydrochar preparation are examined, along with the mechanisms governing hydrochar formation and pore development. Then, this review explores the application of hydrochars in supercapacitors, offering a novel comparative analysis of the electrochemical performance of various biomass-based electrodes, considering parameters such as capacitance, stability, and textural properties. Biomass-based hydrochars emerge as a promising alternative to traditional carbonaceous materials, with potential for further enhancement through the incorporation of extrinsic nanoparticles like graphene, carbon nanotubes, nanodiamonds and metal oxides. Of particular interest is the relatively unexplored use of transition metal dichalcogenides (TMDCs), with preliminary findings demonstrating highly competitive capacitances of up to 360 F/g when combined with hydrochars. This exceptional electrochemical performance, coupled with unique material properties, positions these biomass-based hydrochars interesting candidates to advance the energy industry towards a greener and more sustainable future.

An approach of largely improving the properties of protein-based biopolymers is reported. Cottonseed protein concentrate (CPC) purified from cottonseed protein powder waste, with a protein content of >70% and a plasticizing efficiency of 4.2, was used to produce bioplastic polymer. A prepreg consisting of relatively oriented sisal fiber (SF) was transferred into CPC matrix as reinforcement, giving rise to improved mechanical properties of CPC/SF composites. To enhance interfacial bonding forces between the fiber and polymer, dialdehyde starch, DAS, with varied content (5–30 wt%) was introduced, and the FTIR and NMR results showed that DAS can effectively bridge biomacromolecular chains and form strong chemical bonds within the crosslinked structure. This cross-linking treatment leads to the formation of tight CPC/SF interfaces with strong adhesion, as shown by microscopic images, translating into excellent mechanical performance (e.g. tensile strength 21 MPa), water resistance (e.g. water contact angle 80°) and thermal stability (e.g. glass transition temperature 104 °C) of the composites. The all green composites derived from natural resources with comparable or even superior properties to state-of-the-art biomass-based composites hold great potential for being utilized in larger industries.