Herein, we describe the use of gamma irradiation to prepare hydrogels comprising α-cellulose and cellulose nanocrystal (CNC)-reinforced gelatin in the absence of crosslinking agents. In this study, cellulose was extracted from rice husks by an alkali and bleaching treatment followed by acid hydrolysis to produce CNC. A semi-interpenetrating network (semi-IPN) of hydrogels was developed by the miscibility between gelatin and cellulosic materials. Compared to those prepared from α-cellulose, hydrogels prepared by dispersion of CNCs exhibited remarkably enhanced stiffness and swelling properties, which was ascribed to the uniform distribution of CNCs and their increased crystallinity. Improved pore structure, arrangement, and rigidity of CNC-reinforced gelatin hydrogels, which induced the swelling mechanism resulting in higher and faster water uptake was observed with a scanning electron microscope (SEM), compared to cellulose-reinforced gelatin hydrogels. Moreover, in vitro drug profiling demonstrated that CNC/gelatin hydrogels exhibit good drug loading/release behavior and are thus suitable for use in drug-delivery applications.

PH-sensitive poly(acrylic acid) (PAA) hydrogel reinforced with cellulose nanocrystals (CNC) was prepared. Acrylic acid (AA) was subjected to chemical cross-linking using the cross-linking agent MBA (N,N-methylenebisacrylamide) with CNC entrapped in the PAA matrix. The quantity of CNC was varied between 0, 5, 10, 15, 20, and 25 wt %. X-ray diffraction (XRD) data showed an increase in crystallinity with the addition of CNC, while rheology tests demonstrated a significant increase in the storage modulus of the hydrogel with an increase in CNC content. It was found that the hydrogel reached maximum swelling at pH 7. The potential of the resulting hydrogels to act as drug carriers was then evaluated by means of the drug encapsulation efficiency test using theophylline as a model drug. It was observed that 15% CNC/PAA hydrogel showed the potential to be used as drug carrier system.

Eco-friendly materials such as poly(lactic acid) (PLA) and cellulose are gaining considerable interest as suitable substitutes for petroleum-based plastics. Therefore, amorphous cellulose (AC) was fabricated as a new reinforcing material for PLA biocomposites by modifying a microcrystalline cellulose (MCC) structure via milling. In this study, the mechanical properties, thermal properties, and degradability of PLA were analysed to compare the effects of both MCC and AC on PLA. The tensile and impact properties improved at an optimum value with AC at 8 wt% and 4 wt% fibre loading, respectively. Notably, a scanning electron micrograph analysis revealed improved AC fibre–matrix adhesion, compared with MCC fibre–matrix adhesion, as well as excellent interaction between AC and PLA. Both MCC and AC improved the hydrolytic degradation of PLA. Moreover, the biocomposites with AC exhibited superior degradation when the incorporation of AC improved the water absorption efficiency of PLA. These findings can expand AC applications and improve sustainability.

Mechanical behavior of short Twaron fiber thermoplastic natural rubber (TPNR) has been studied with respect to fiber loading and extrusion rates. The composites are prepared at two different compositions of NR/LLDPE matrixes i.e., 60/40 and 40/60. Twaron fibers are varied from 0 to 25% in the composites. The temperature profile for extrusion is 140, 145, 150, and 155°C for feeding zone, melting zone, mixing zone, and die respectively with the extrusion rate of 30, 50, 80, and 100 rpm. It has been found that the tensile strength, Young’s modulus, and impact strength increases with fiber loading, but the strain at break decreases. The optimum fiber loading in the system is found to be 20% in both blends. However, there is no effect of extrusion rate on the strength of composite observed.