Materials Science Forum Vol. 1139

Abstract: This paper, investigated the effects of expandable graphite and ammonium polyphosphate on the flame-retardant properties of nitrile butadiene rubber. Several formulations of NBR were prepared by combining different ratios of expandable graphite and ammonium polyphosphate to evaluate their synergistic flame-retardant effects. The results show that the combination of expandable graphite and ammonium polyphosphate significantly enhances the flame-retardant effects of nitrile butadiene rubber, as evidenced by improved limiting oxygen index values, horizontal burning rates decreased and passed the UL-94 V1 when the ratio of expandable graphite and ammonium polyphosphate as (2/1). Results from TGA demonstrated that the ammonium polyphosphate/expandable graphite combination could retard the degradation of rubber by promoting the formation of a compact char layer on the condensed phase surface. This char layer effectively protects the matrix from heat penetration and the diffusion of flammable gas products, resulting in better flame-retardant performance. The effect of flame retardant on the mechanical properties of nitrile butadiene rubber was also evaluated. The results showed that the mechanical properties decreased with increasing flame retardant content.

Abstract: Edible plastics/films or biopolymers are biodegradable materials which are normally applied as food packaging. This type of packaging has been used for centuries to protect food products by avoiding food deterioration and extending its shelf life. Due to the increasing concerns about health and the environment, edible films are made from biomaterials to produce safe, edible, and environmentally friendly materials. In this study, the biopolymer’s compositions are combined from different types of hydrocolloids (polysaccharides base) with gel forming ability and additives for better structure. The film is formed by applying wet formation (solvent casting technique) and dried at 55°C to create thin films. The thickness, tensile strength (TS), elongation at break (EBA), contact angle, water vapor transmission rate (WVTR), water solubility and oil solubility were determined at different proportions of used hydrocolloids. The plasticizer glycerol was added at different concentrations (10, 20, 30% w/w) for further investigation of the film’s properties.

Abstract: Chitosan (CS), with its non-toxic and antibacterial properties, and Poly(ε-caprolactone) (PCL), known for its biodegradability and biocompatibility, are crucial materials in medical applications. This study proposed a solution utilizing electrospinning to manufacture fibers with nanometer-sized core-shell structures from these materials, with CS serving as the fiber core and PCL forming the shell. The influence of manufacturing technology parameters on fiber size and morphology was thoroughly researched and investigated. The solvent system used, Chloroform/Dimethylformamide (DMF), ensured complete solubility, viscosity control, conductivity, and proper solvent evaporation. Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) results clearly demonstrated the morphology and internal structure of the nanofibers. The water contact angle (WCA) measurements of the fiber membrane showed almost no significant change over time, indicating strong hydrophobicity of the nanofibers. Additionally, the FTIR spectrum revealed distinct core-shell layers without any blending between them, while DSC analysis showed the thermal properties of fiber membranes. In summary, the electrospinning of nanofibers proved to be stable, producing thin fibers with an average diameter of approximately 400 nm. These findings are expected to significantly enhance the applicability of CS/PCL nanofibers across various fields, including healthcare and smart agriculture.