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.
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.
Two inflatable-types of dielectric sensor (one sided-inflatable (OIDS) and two sided-inflatable (TIDS)) were fabricated using acrylic rubber coated with a compliant electrode. The effect of air-pressure (P) on capacitance (C), coated area of compliant electrode, vertical deformation (R inf ) and the volume change were studied. An increase in P expanded the volume, area of coated electrode and R inf respectively. In terms of R inf , OIDS and TIDS were stretched above 500 and 800% while swollen to values higher than 23,000 and 77,000% respectively, in terms of volume expansion. These expansions caused changes in the output C for sensors, due to changes in polarization. The measured normalized sensitivity coefficients (nGF), a fractional change in pressure (ΔP/P o ) versus area strain (ΔA/A o ) was ∼20.73 and ∼13.6 for OIDS and TIDS respectively. TIDS reached 1.1 kPa -1 at 0.4-0.68 kPa while OIDS recorded 0.12 kPa -1 at 0.4-1.1kPa pressure, in terms of sensitivity (S) based on flexible capacitive sensors ((ΔC/C o )/(ΔP)). The OID harvested an electrical energy of ∼208μJ/s at area expansion ∼186% and could theoretically be used to harvest ∼18J in a day. Therefore, the sensors show promising multifunctional characteristics suitable for applications including; detection of pressures from natural disasters windstorm/typhoon and for harvesting energy.
High filler content hybrid polymer composites create complicated drilling behavior, which is attributed to stiffness dissimilarity, fracturing of brittle particles, and spatially non-uniform stress transfer. This research article presents a report on the performance of drilling and the formulation of predictive equations of an epoxy matrix that is reinforced with 15 wt.% eggshell-derived CaCO 3 and 35 wt.% iron dust (total filler: 50 wt%; matrix phase: 50 wt% epoxy resin-hardener system, summing to 100 wt% in total). The study of drilling trials was modeled based on the Taguchi L25 orthogonal array that allowed independent variation of spindle speed, feed rate, and measurement of the outcomes of drilling, delamination factor, circularity error, and cylindricity deviation. The results of multivariate statistical analysis showed that feed rate was the most influential variable, as it explained more than 60% of the variance in delamination and greater than 55% of the variance in geometric deviation. SEM of machined surfaces indicated a homogeneous distribution of fillers and an absence of interfacial voids, which supports damage mechanisms based on the cracking of the matrix, particle pull-out, and brittle CaCO 3 particle fracture. A deep neural network (DNN) was later developed to reflect the nonlinear process-response associations, with an excellent predictive accuracy (R 2 ) over standard regression and shallow artificial neural network designs. Confirmation experiments at the optimal condition of 1800 rpm spindle speed and 0.05 mm/rev feed rate yielded prediction deviations within ±3% for all responses. The experimental-computational method that has been developed herein is a viable approach to quality-based optimization of the drilling of sustainable hybrid composites containing high amounts of filler.
