Journal of Composites Science

Poor fiber–matrix interfacial adhesion limits the mechanical performance of synthetic fiber-reinforced cementitious composites. To overcome this limitation, this study investigates the impact of surface-treating polypropylene (PP) macrofibers with graphene oxide (GO) on single-fiber pullout behavior. The thermal and structural response of the treated fibers was characterized using Differential Scanning Calorimetry (DSC), and mechanical performance within the cementitious matrix was quantified. DSC analyses revealed changes in the thermal response of the polymer surface caused by the coating. In pullout tests, surface modification with GO resulted in higher resistance values at specific displacement levels, fR0.5 and fR3.5, showing increases of 20% and 18%, respectively. It is concluded that the GO coating effectively acts as an interfacial anchoring agent, optimizing interfacial shear transfer and enhancing the composite’s energy dissipation capacity in cementitious structures.

This study investigated the low-temperature thermal treatment of EVA encapsulant from an end-of-life 180 Wp monocrystalline PV panel while evaluating the preservation of recovered crystalline silicon. TGA showed that EVA underwent major decomposition between approximately 330 and 480 °C, with an onset temperature of 310.4 °C and mass loss of 94.34%. Thermal treatment was subsequently conducted at 300–500 °C for 30–50 min under nitrogen using a Taguchi L9 design. XRD analysis showed substantially improved silicon diffraction intensity after treatment, while the 300 °C residues were unsuitable for analysis due to incomplete EVA decomposition. Taguchi-based analysis was used as a preliminary screening approach to compare the investigated treatment conditions. Within the experimental range, 400 °C for 40 min was identified as a practical treatment condition based on the measured XRD response, treatment duration, and estimated furnace energy requirement. The results indicate that controlled thermal treatment promoted substantial EVA decomposition while maintaining detectable crystalline silicon in the treated material.

Conventional seedling substrates such as rockwool and peat raise environmental concerns associated with disposal and resource extraction. Here, we investigate nanoclay–agarose hydrogels as candidate sustainable and biodegradable alternatives for seed germination and early plant growth under greenhouse conditions. Agarose hydrogels incorporating sodium bentonite nanoclay (NC) or activated carbon (AC) were prepared and evaluated for their structural, thermal, and biological performance using Brassica rapa (bok choy) as a model crop. Structural and physicochemical analyses revealed lamellar architectures, spectral features consistent with agarose–filler interactions, and composition-dependent thermal decomposition profiles. Dried NC hydrogels exhibited more open structures than the comparatively compact AC hydrogels. After 15 days under greenhouse conditions, NC40 (40 wt% nanoclay relative to agarose) achieved 100% germination and the highest mean fresh and dry biomass among the substrates compared for biomass, including rockwool and peat pellets. Over 42 days of soil burial, pure agarose and AC hydrogels showed more extensive visible breakdown consistent with biodegradation of the agarose matrix, whereas NC hydrogels retained their structural form for longer. These findings highlight nanoclay–agarose hydrogels as biodegradable, eco-engineered substrates with the potential to replace conventional growing media and advance sustainable agriculture.