Journal of Plastic Film & Sheeting

Polymer coatings are widely employed to improve the surface performance of engineering components by providing corrosion resistance, wear protection, hydrophobicity, biocompatibility, and functional surface characteristics. Among various deposition methods, thermal spray technologies have emerged as highly effective methods for fabricating polymer and polymer-based composite coatings on metallic, ceramic, and polymeric substrates. This review provides a comprehensive overview of thermally sprayed polymer coatings, focusing on processing methods, coating characteristics, and key application areas, along with commonly used polymers such as polyethylene (PE), polyamide (PA), polyimide (PI), polyurethane (PU), polyether ether ketone (PEEK), polyethylene terephthalate (PET), and fluoropolymers. This review critically examines the development of polymer and polymer-based composite coatings fabricated via thermal spray techniques, including flame spraying, high-velocity oxy-fuel (HVOF), plasma spray (PS), and cold spray (CS) processes. Each process offers distinct advantages in terms of particle heating, velocity, deposition efficiency, coating density, and substrate thermal exposure. Flame spraying remains the most established method for large-scale polymer coating deposition, whereas cold spray has attracted increasing attention due to its low-temperature solid-state deposition capability that minimizes thermal degradation. High-velocity oxy-fuel (HVOF) and plasma spray (PS) processes are particularly suitable for producing dense coatings and polymer ceramic composites with improved wear resistance. Functional properties including wear resistance, corrosion protection, ice-phobic behaviour, self-lubrication, antimicrobial packaging, and biofouling/fouling resistance, and biomedical applications are systematically discussed. Future opportunities are highlighted for the development of multifunctional, high-performance, and sustainable polymer-based thermal spray coatings for advanced applications in aerospace, marine, energy, transportation, and infrastructure sectors.

The multi-layer co-extrusion blown film machine is capable of producing composite films with multiple advantages by integrating materials with distinct properties, thereby endowing the film material with excellent barrier performance and high strength. The automatic air ring can dynamically adjust the cooling rate of the film bubble at various angles in real time via its air temperature and air volume regulation control system, which enhances the uniformity and precision of film thickness and consequently ensures the quality of the multi-layer co-extrusion composite film. Based on an investigation into the working principle of the automatic air ring and considering the airflow characteristics within it, a turbulent model for the automatic air ring flow field for the multi-layer co-extrusion blown film machine has been established using the Realizable k-ε flow field model. This study analyzes and investigates the automatic air ring flow field of the multi-layer co-extrusion blown film machine from perspectives such as air ring structural parameters and blown film process parameters. Furthermore, the coupling mechanism of multiple physical quantities during film bubble shaping is explored, and the control parameters of the automatic air ring flow field are optimized. By regulating the flow state of the cooling air within the automatic air ring, the film bubble stability is ensured. A multi-physical field coupling experimental study of the multi-layer co-extrusion blown film machine elucidates the regulatory mechanism of process parameters on film thickness distribution: increasing the inlet air temperature by 20 K accelerates the film thickness thinning rate; an asymmetric air door layout reduces the film thickness fluctuation range while minimizing the temperature difference to 0.53 K. Through collaborative optimization of temperature and air volume, both the film thickness uniformity and the bubble stability are significantly improved.

Per- and polyfluoroalkyl substances (PFAS) represent a diverse group of synthetic chemicals widely utilized in industrial processes, consumer goods, food-contact materials, and plastics due to their exceptional chemical stability and resistance to degradation. However, their pervasive presence in the environment, persistence, and ability to bioaccumulate have raised increasing concerns about human exposure and associated health risks. Dietary intake, through contaminated food, drinking water, and food packaging materials, serves as a primary route of exposure, placing the gastrointestinal tract at the center of PFAS–host interactions. Recent research suggests that the gut microbiome plays a significant role in modifying PFAS toxicokinetics, bioavailability, and biological effects. This review consolidates current insights into the complex relationship between PFAS and the gut microbiome, detailing mechanisms such as microbial uptake, bioaccumulation, enzymatic defluorination, β-oxidation-like biotransformation processes, and alterations in bile acid and short-chain fatty acid metabolism. Conversely, exposure to PFAS can disrupt microbial diversity, compromise intestinal barrier integrity, and affect various host functions, including immune response, metabolism, liver and kidney health, and neuroendocrine regulation. Experimental studies, data from human cohorts, and findings from multi-omics approaches reveal that microbiome-driven changes contribute to chronic health issues like inflammation, metabolic disorders, insulin resistance, and immune system dysregulation. Additionally, advancements in metagenomics, metabolomics, and transcriptomics are shedding light on the intricate mechanisms underlying PFAS–microbiome interactions. These developments underscore the potential for microbiome-targeted interventions to mitigate the adverse health effects of these enduring environmental pollutants.

This work develops a structurally CO₂-derived, high-performance biodegradable packaging material by melt-blending poly (propylene carbonate phthalate-ran-cyclohexene carbonate phthalate) (PPC-X) with a CO₂-based polyurethane (PPC-PU) as an effective plasticizer. The resulting composites exhibit a dramatic plasticizing effect: elongation at break increases from 3.52% (neat PPC-X) to 47.84% at 20 wt% PPC-PU while maintaining a tensile strength of 22.84 MPa and increases to 168.71% at 30 wt%. DMA, DSC, and SEM analyses confirm excellent miscibility and a homogeneous morphology, with the mechanism attributed to synergistic plasticization, hydrogen bonding, and dipole interactions. The optimized composite (20 wt% PPC-PU) also shows superior barrier properties, with permeability coefficients of 0.54 cm³·mm/(m²·day·atm) for CO₂, 1.41 cm³·mm/(m²·day·atm) for O₂, and 3.70 × 10^-4 g·mm/(m²·day) for water vapor, outperforming commercial biodegradable (e.g., PLA/PBS/PBAT) and petroleum-based (e.g., PET) films. The material retains its inherent biodegradability and exhibits improved thermal stability (ΔT_d1max ≈ +10°C) with minimal Tg change (ΔTg <4°C). This study establishes a sustainable strategy to create tough, high-barrier PPC-X-based packaging films, addressing a critical need for petrochemical-free alternatives.

This study focuses on controlling the interfacial adhesive strength between heat-sealed styrene-co-butadiene block copolymer (SBC) and glycol-modified polyethylene terephthalate (PETG) multilayer films. In comparison, the interfacial bond strength of coextruded PETG/SBC/PETG films was weaker. The lamella structures of SBC and free polybutadiene increased the interfacial adhesive strength. The coextruded films with applied thermal pressing were also examined. When exposed to heat, the interfacial adhesive strength improved. The butadiene layer segregated along the adhesive interface, as observed by transmission electron microscopy. The butadiene layer improved the interfacial adhesive strength. The applied pressure caused the butadiene layer to segregate in a parallel manner along the adhesive interface. The developed lamellar structure did not increase adhesive strength. We considered that the adhesive strength decreased due to a thinner butadiene layer with higher pressure. We concluded that adhesive segregation along the adhesive interface improved the bond strength.