Starch-gelatine films are promising biodegradable materials for active food packaging, but their industrial adoption beyond laboratory-scale studies is currently limited by formulation-dependent performance, processing limitations and inconsistent experimental reporting. This critical review demonstrates how formulation, processing history, polymer architecture and environmental conditions determine the mechanical, barrier and active properties of starch–gelatine films. Solution casting is widely used for laboratory studies, whereas extrusion, thermo-compression and related thermoplastic methods provide a more direct pathway to continuous manufacture. However, published evidence for process robustness, thermal stability, throughput and post-processing barrier performance is limited. Natural antioxidants and agro-industrial by-products can provide antioxidant, antimicrobial or sensing functionality, but their effectiveness depends on matrix interactions, retention, release or migration and validation in food systems. Relative humidity is also critical because water sorption and plasticization can strongly affect water vapor and oxygen transport. A further limitation is not the absence of recognized standards, but their inconsistent adoption and implementation, together with incomplete reporting of key test conditions across studies. This review proposes an integrated framework linking processing–structure–property relationships with minimum reporting requirements, food-contact safety, application validation and industrial scalability, while identifying future priorities in quantitative structure–property analysis, pilot-scale process validation and standardized reporting to support reliable data-driven design.
Braid-reinforced thermosetting pipes (BRTPs) are rapidly displacing metallic and filament-wound composite pipelines, but their mechanical performance is highly sensitive to manufacturing variables. Here, Response Surface Methodology (RSM) was used to map and optimize the processing parameters–mechanical performance space defined by braiding angle (55°, 65°, 75°), reinforcement layer count (1–3), and matrix system (epoxy, vinyl ester, polyester). BRTPs were fabricated for all factor combinations and tested to relevant ASTM standards for axial tensile strength/modulus, hoop tensile strength/modulus, and pipe stiffness at 5% and 10% diametral distortion. Analysis of variance identified braiding angle and layer count as the primary drivers of stiffness and strength, with matrix type governing deformation resistance and load transfer efficiency. Quadratic RSM models demonstrated high predictive accuracy, with coefficients of determination (R 2 ) of 0.9944, 0.8969, 0.9981, 0.7422, 0.9993, and 0.9994 for the respective responses, and enabled multi-objective optimization. The optimum configuration (epoxy matrix, three layers, 75° braiding angle; desirability = 0.822) yielded experimentally validated values of 80 MPa hoop tensile strength, 0.66 GPa hoop tensile modulus, 18.5 MPa axial tensile strength, 0.643 GPa axial tensile modulus, 11.86 MPa pipe stiffness at 5%, and 15.46 MPa at 10% deflection, all within <5% prediction error. This provides an actionable processing window for high-reliability BRTPs in harsh oil-and-gas service.
In an effort to reduce waste and manufacturing costs in automotive assembly tooling, this study evaluates the potential of replacing the traditional machining of technical plastic connector (CH) supports with Fused Deposition Modelling (FDM) using Polylactic Acid (PLA). Comprehensive experimental evaluations were conducted using different printing parameters to cover mechanical properties (tensile, flexural and compressive strength), environmental durability (thermal ageing, moderate heat exposure and chemical resistance) and functional performance (torque, drop and cyclic load). The results confirm that FDM-manufactured PLA components meet the operational requirements for low-volume automotive tooling. Specifically, a cubic infill density of 20% was found to provide the optimal balance of structural integrity, resource efficiency, and mechanical durability, offering a sustainable and cost-effective alternative to conventionally machined plastics.
The mechanical performance of short carbon fiber (CF)-reinforced styrene–butadiene rubber (SBR) composites is strongly governed by stress transfer across the fiber–matrix interphase. In this study, a multiscale finite element framework was developed to investigate the interfacial behavior of surface-modified short CF/SBR composites containing randomly distributed fibers. The carbon fibers were modified through oxidation, TESPT grafting, and rubber sizing treatment to enhance interfacial adhesion with the rubber matrix. Two interfacial modeling approaches, namely the continuum interphase model and cohesive zone modeling (CZM), were employed to describe the mechanical response of the fiber–matrix interface. The effects of interphase stiffness, representative volume element (RVE) size, and interfacial damage evolution on stress transfer, strain localization, and the effective mechanical response were systematically investigated. Numerical predictions were assessed through comparison with experimental mechanical properties and scanning electron microscopy (SEM) observations. The results demonstrated that the interfacial characteristics significantly influence local stress–strain fields, damage evolution, and the predicted effective stiffness of the composite. The developed multiscale framework provides valuable insights into the role of the fiber–matrix interphase in governing the mechanical behavior of short fiber-reinforced elastomer composites and offers an effective methodology for the design and optimization of rubber-based structural materials.
The separation of post-consumer plastics at high efficiency levels serves as a critical step for circular economy development and environmental protection. The research examined how different air flow rates and three depressants including tannic acid (TA) and polyvinyl alcohol (PVA) and polyethylene glycol (PEG) affect the flotation behavior of engineering plastics polycarbonate (PC) and polyoxymethylene (POM) and acrylonitrile–butadiene–styrene (ABS). The column flotation cell operated under controlled conditions to measure flotation recovery rates at different aeration levels and depressant concentrations. The results demonstrated that flotation efficiency depends heavily on the interaction between hydrodynamic conditions and chemical factors. The baseline aeration conditions enabled high floatability of PC and ABS but TA and PVA depressants reduced their recovery rates and PEG showed variable effects that depended on concentration levels. The absence of depressants allowed POM to reach 100% recovery at elevated air flow rates but TA and PVA consistently reduced its recovery. The operational synergy maps demonstrated specific conditions where air flow rates either supported or diminished the effectiveness of depressant chemicals. The findings demonstrate that engineering plastic recycling reaches its best results through combining optimized air dispersion levels with appropriate depressant amounts in the design process. The experimental results offer useful information for creating a large-scale flotation separation method for waste electrical and electronic equipment polymers.
