Household plastic waste and industrial polymer matrix composite material scrap present two scales of problems that can lead to pollution and other environmental issues. Recycling waste and scrap has become increasingly important and has drawn tremendous attention as a promising approach to solving the growing polymer pollution issue. This study aims to create energy-efficient and scalable procedures to manufacture hybrid composite materials using household thermoplastic waste and industrial thermoset matrix composite scrap for the first time to our best knowledge, and evaluate the structural performance of upcycled fiber-reinforced composites. Recycled scrap of pultruded glass fiber vinyl ester composite (rComposite) was mechanically split with an energy-efficient process and subsequently molded with recycled household high-density polyethylene (rHDPE) waste to produce thermoset composite reinforced thermoplastic matrix (rComposite/rHDPE) composites at different rComposite contents, i.e., 20, 27, and 35 wt%. Various characterization methods, including Fourier transform infrared spectroscopy, differential scanning calorimetry, optical microscopy, and scanning electron microscopy analyses, were performed to evaluate the constituent materials and the molded composite. Mechanical testing was also conducted to evaluate the mechanical properties of the composites with different rComposite contents. It was found that the tensile and flexural properties of the rComposite/rHDPE composite increased with increasing rComposite content. There was a 256% increase in tensile strength and an 885% increase in tensile modulus for the 35%-rComposite reinforced rHDPE composite over neat rHDPE, respectively. Overall, this study presents a potential approach of recycling household plastic waste and polymer matrix composite material scrap by developing a hybrid composite material with great mechanical properties.
Multilayer composite materials are used in advanced engineering as a material for heavy-duty products. However, the use of multilayer composite materials requires consideration of their inherent specific properties, such as anisotropy of mechanical characteristics and the possibility of the presence of hidden defects in the form of discontinuity of the material along the interfaces of individual layers (laminations). Evaluation of interlayer failures throughout the life cycle is critical to reducing composite product safety risks. In this article, the analysis of interlayer defects in composites employs comprehensive control, including several non-destructive testing methods: visual inspection, ultrasonic flaw detection, active thermography, and numerical modeling. Interlayer defects obtained as a result of low and high-speed impact on multilayer composite materials are considered. It has been found that the results from numerical modulation of interlayer defects and from non-destructive inspection of defects such as laminations, obtained by different methods, agree satisfactorily.
Rare-earth (RE)-containing magnesium sheet alloys are promising for lightweight structures because they can reduce anisotropy and improve warm formability. Their industrial relevance, however, should be assessed not only through mechanical performance, but also through process-energy demand, corrosion durability, and critical-raw-material considerations. This perspective examines Mg–Zn–RE sheets, with ZE10A as an anchor case, to connect three issues that are often treated separately: low-temperature warm-forming windows, deformation-induced microstructural stability, and corrosion-film kinetics. Current evidence indicates that in the approximately 250–300 °C range, recovery and incipient dynamic recrystallization may improve formability while limiting major grain or phase evolution. Under these recovery-dominated conditions, we propose, as a working hypothesis, that the influence of thermomechanical history on corrosion is mediated primarily by defect architecture, near-surface heterogeneity, and the formation and breakdown kinetics of dynamic, non-passivating films, rather than by extensive precipitation or classical microgalvanic changes. A screening-level discussion of process-energy demand, together with a database-based comparison of the embodied energy and carbon footprint of selected rare-earth elements, is used to frame responsible alloy and processing decisions without claiming a full life-cycle assessment. The perspective concludes with a research roadmap integrating history-faithful forming tests, correlative microstructure mapping, time-resolved electrochemistry, and transparent sustainability assumptions to support predictive manufacturing design rules for Mg–RE sheets.
