Polyphenols represent a highly abundant group of plant-derived natural compounds, characterized by remarkable structural diversity and potent antioxidant activity. Based on their chemical structures, polyphenols are broadly categorized into flavonoids, phenolic acids, stilbenes, tannins and lignans. Among these polyphenolic groups, tannins stand out for their large and complex polyphenolic frameworks and strong metal-chelating abilities. Tannic acid, a well-known hydrolyzable tannin, is one of the most extensively utilized polyphenols because of its dense phenolic composition, strong metal-chelating ability and capacity to form diverse non-covalent interactions. This review highlights recent advancements and applications of tannic acid-based micro- and nano-formulations, with particular emphasis on their roles in emulsion stabilization, enhancement of UV-barrier properties and food safety sensor applications.

Enhancing the interfacial bonding performance between carbon fibers (CF) and thermoplastic resins is extensively researched. In this study, we propose a novel method for the synergistic surface modification of carbon fibers using a silane coupling agent and poly-carbonate diol (PCDL), which significantly improves the interfacial compatibility between CF and polycarbonate (PC). Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) confirmed the successful grafting of silane onto the surface of CF and subsequent PCDL sizing. Mechanical characterization showed that the modified carbon fiber composites exhibited a 47.3% increase in interlaminar shear strength (ILSS) relative to the unmodified system. Notably, with a loading of 10 wt%, the modified fibers improved the tensile strength, flexural strength, and notched impact toughness by 36.2, 38.5, and 39.6%, respectively. The impact fracture surfaces exhibited typical characteristics of ductile fracture, with a dense and gap-free interfacial layer forming between the fiber and the matrix, indicating that the efficiency of stress transfer was effectively enhanced. The findings of this study are expected to provide a valuable technical reference for the fabrication of carbon fiber–reinforced thermoplastic composites.

This study investigates the interaction between poly(butylene adipate-co-terephthalate) (PBAT) and amber powdered waste (AbW) from jewelry at different filler concentrations (0, 1, 2.5, and 5 wt%) obtained via melt mixing in a corotating twin screw extruder. The resulting materials were pelletized and processed using two techniques: 1) cast film extrusion and 2) injection molding. The shaped specimens exhibited excellent interfacial adhesion. Thermal behavior, as assessed by Vicat softening temperature (VST), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA), showed minimal variation among the composites. Despite similar melt flow rate (MFR) values among the samples, the incorporation of AbW affected the behavior of the polymer during cast film extrusion. Consequently, the composite films exhibited lower tensile mechanical parameters (tensile strength, Young’s modulus, stress and strain at break) compared to the neat PBAT film. In turn, the injection molded composites showed improved tensile, flexural, and impact parameters compared to their neat counterpart. Additionally, a slight decrease in water contact angle (WCA) suggested increased surface hydrophilicity of the extruded films. These findings demonstrate the potential of AbW as an additive for biopolymer composites with enhanced mechanical performance. The increased surface hydrophilicity is particularly relevant for applications targeting biocompatibility and biodegradability.

The current experimental investigation presents a comparative evaluation of selected biodegradable polymer blends and their composites, focusing on their material properties. Two biopolymers, polylactic acid (PLA) and polybutylene adipate-co-terephthalate (PBAT), along with pineapple fibers (F), as bio-reinforcement were taken for the analysis, which was conducted in two stages: During first stage, PBAT was melt-blended with PLA in varying weight fractions (10, 20, 30, 40, and 50 wt%) to produce PLA/PBAT blend (B) and in second stage, PLA, PBAT, B 80/20 blend were reinforced with pineapple fiber (10, 20, and 30 wt%). The samples were fabricated using extrusion-injection molding. The samples were characterized for density, thermal degradation, crystallinity, and mechanical behaviour. Among the blends, the optimal B 80/20 combination exhibited tensile strength, flexural strength, and elongation at break of 47.9±2.4, 88.2±5.4 MPa, and 330.6±10.47%, respectively. Results indicate that the PLA-based composites (PF) exhibit significantly better density, tensile strength, and flexural strength as compared to neat polymers, blends, blend-based composites (BF), and PBAT-based composites (TF). Among the PF composites, the PF 70/30 composite demonstrated superior performance, with maximum tensile and flexural strength values of 73.9±1.3 and 107.1±4.3 MPa, respectively.

The study investigates the use of repurposed milled carbon fibre (mCF) as reinforcement for polyamide 66 (PA66) in gear applications, addressing environmental and cost concerns of virgin carbon fibres. Neat PA66 and PA66 composites reinforced with mCF, glass fibres (GF), and carbon fibres (CF), with and without polytetrafluoroethylene (PTFE), were injection moulded and evaluated for microstructure (fibre length), thermal, mechanical, surface, and tribological properties, as well as gear performance under VDI 2736 guidelines. CF reinforced composites showed the highest modulus and tensile strength, followed by mCF and GF. PTFE reduced modulus and strength in binary composites. All reinforced composites significantly lowered the coefficient of friction (COF) and wear rate compared to neat PA66, with mCF showing the most notable improvements. PTFE slightly improved tribological performance only for GF (wear) and CF (COF) composites. In gear testing, binary composites outperformed neat PA66, with CF performing best, followed by mCF and GF. Ternary composites had slightly lower performance than their binary equivalents. Correlation analysis showed that gear performance is closely linked to structural integrity. Failure analysis revealed higher crack susceptibility in mCF reinforced gears due to shorter fibre length. The findings highlight mCF reinforced PA66 as a sustainable, cost-effective material for durable polymer gears.