Mohamed El-Sakhawy

Paper ages naturally by heat, oxidation, and hydrolysis, which cause a progressive loss of mechanical strength. This study achieved a high yield of 93% amorphous SiO2 from rice husk waste through controlled calcination at 450°C (3 h) and 800°C (2 h), alkaline extraction with 2.5 N NaOH, acid precipitation with 1 N HCl and freeze-drying. The resulting nano-silica particles were incorporated into a 3% w/v hydroxyethyl cellulose (HEC) binder to prepare a 2% w/v impregnation solution, which was applied to paper sheets by soaking for 0–20 min. Structural analyses (FTIR, XRD, SEM) confirmed the successful preparation of hydroxylated amorphous silica and uniform deposition on paper fibers. Optimal mechanical performance was achieved at soaking times of 10–15 min, where a maximum weight percent gain (WPG) of 35.27% was recorded. Post-aging tensile strength and elongation improved by up to 25% and 94%, respectively, compared to uncoated paper. The limiting oxygen index (LOI) values increased from 18.0 to 22.3 vol.%, indicating improved flame retardancy. Density Functional Theory (DFT) calculations revealed that the nano-silica coated paper exhibited a wider HOMO–LUMO energy gap (1.342 to 1.803 eV) and higher chemical hardness (0.671 to 0.902 eV), confirming enhanced chemical stability and reduced susceptibility to oxidative degradation. This study combine bio-derived nano-silica from rice husk waste with DFT quantum chemical analysis to elucidate the molecular-level anti-aging mechanism of a paper coating system. The study demonstrates a sustainable route for converting agricultural waste into functional nanomaterials for paper preservation and performance enhancement.

Due to its excellent antiseptic efficacy and antimicrobial properties, propolis has shown attractive advantages in wound dressings. However, an inclusive review of the propolis-based materials as a wound dressing is still lacking. The current short review summarizes the skin wound healing process, relates evaluation parameters, and then reviews the refined propolis-based materials dressings such as antimicrobial property, adhesion and hemostasis, anti-inflammatory and substance delivery. The approaches implemented to achieve these functions are classified and discussed. Furthermore, applications of propolis wound dressing for treating different types of wounds such as heal wounds, burns, and ulcers are presented. The future directions of propolis-based wound dressings for wound healing are further proposed. This review showed that propolis-based materials might be a promising new dressing for wound occlusion and tissue repairing.

Propolis has been utilized as a natural bio-product from beekeeping for various applications such as wound healing, food packaging, and food production. However, the applications of propolis as food additives are limited by the low oral bioavailability, bitter taste, and aroma. The current review investigates the recent techniques, such as encapsulation, microencapsulation, film casting, and composite materials, which enhance the propolis availability for food applications. Propolis enhances the mechanical properties, oxygen and moisture barrier, antioxidant, and microbial resistance of the resulting materials. Therefore, the utilization of propolis composites as an effective food packaging in the future is promising. Based on these results, the food industry can benefit from developing propolis-based composite. Graphical Abstract