Volume 44, Issue 2

Biopolymer-based nanocomposites have gained significant attention in biomedicine due to their unique properties and potential applications. These nanocomposites combine biopolymers, natural polymers derived from renewable sources, with nanoparticles or other nanoscale materials to create materials with enhanced properties and functionalities. Biopolymers that are used to make bio-nanocomposites are cellulose, alginate, chitosan, starch, polylactic acid (PLA), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), etc. These have different properties, and they can be used in several types of treatments. Scaffolds frequently employ polylactic acid-gelatin, nanocellulose, and chitosan. Studies have shown that some special types of hydrogel films have proven beneficial in anticancer treatment. Synthetic and naturally occurring substances such as PLA, polyvinyl alcohol (PVA), guar gum, and chitosan are employed in the drug delivery system. Nanocomposites such as silver nanoparticles with chitosan, sulfated polysaccharides, and thyme-loaded carrot nanocellulose or starch biopolymer nanocomposites have been used to stop bacterial development. This review article provides a comprehensive insight into biopolymer-based nanocomposites and their uses. Also, it has been incorporated into fields such as biosensors, bioimaging, blood clotting, immunomodulation, antibacterial and antiviral drugs, and food packaging. Hence, the primary objective of this review is to provide an overall perspective on biopolymer nanocomposites in nanomedicine.

Cesium tungsten bronze (CsxWO 3 )-doped PEG/sweet potato form-stable composites are fabricated through a facile two-step method of lyophilization and vacuum impregnation. Abundant starch microsphere enhances the PEG loading capacity above 72 % and also supplies capillary force as well as hydrogen bonding to improve the form-stability of the composites. Here, the latent heat, relative crystallinity (Xc), and light-thermal conversion efficiency of the system with 0.99 wt% CsxWO 3 reach to 137.7 J/g, 97.7 %, and 83.5 %, respectively. The light-thermal conversion efficiency increases from 64.3 % to 91.1 % with 2.00 wt% CsxWO 3 . Besides, the composites exhibit improved thermal stability and excellent thermal reliability. The prepared bio-based composites with low-cost have broad application prospects in the field of energy storage.

To prevent the weathering deterioration of stone building heritages in Putuo Zongcheng Temple, the fluorinated acrylate copolymer was prepared with methyl methacrylate, n -butyl acrylate, and 2,2,3,4,4,4-hexafluorobutyl methacrylate as monomers. The structure and surface morphology of the copolymer were described by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). The antiaging of the copolymer was studied by the ultraviolet aging test; the contact angle and imbibition spontaneous tests were performed to estimate the wettability alteration of the copolymer emulsion. Results show that the fluorinated copolymer with 32.54 % HFMA content possesses optimal aging resistance and superb hydrophobicity. The contact angles of coated samples range from 96.90° to 125.80°. Considering the influence of water on rock weathering, the fluorinated copolymer coating is a potential method to avoid the degrading of stone heritages.

In this paper, the self-reinforced single polymer composites (SR-SPCs) with different mechanical properties were obtained by compound injection molding technology, and the micro-morphology of these samples was observed. Then, using structured statistical methods, analysis of variance, and response surface methodology, study the effects of various molding variables on material morphology and properties and determine the most important molding variables and their interactions. Finally, the associated experimental data are fitted by the least squares minimization program, and the relevant dimensionless equations are obtained. The purpose is to objectively analyze the influence mechanism of molding parameters on SR-SPCs and establish a mechanism model. It was found that temperature change was the most important factor affecting the morphology and mechanical properties. The degree of molecular orientation is the most important factor to determine the tensile strength and elastic modulus of the sample. The change of crystallinity is the most important factor related to the elongation at break. By establishment relevant dimensionless equations, the influence of molding parameters on the mechanical properties of SR-SPCs, such as tensile strength and elastic modulus, was preliminarily studied.

In this study, adhesive bonding of aluminum (Al) to glass fiber reinforced polymer (GFRP) was investigated using finite element analysis to optimize bond strength. Mechanical surface preparation has a great influence on the chemical properties (increasing surface energy and creating a stronger bond) and mechanical properties (creating mechanical interlocking and increasing friction) of adhesive bonding. Hence, the response surface method was employed to examine the influence of groove number (1, 3, 5), groove angle (0, 45, 90°), groove shape (V-shape, square, concave), and joint type (metal–metal, metal–composite, composite–composite) on the tensile strength of the bond. To simulate the bond behavior of Al/GFRP under different parameter conditions, the cohesive zone model was used to consider the crack growth. Optimization results obtained by the desirability function method showed that the maximum bond strength was achieved with a groove number of 1, groove shape of square, groove angle of 0°, and metal–metal joint type. The optimization results predicted by the desirability function and finite element analysis were in good agreement with those obtained by experimental tests.