Plastic Coatings Research Articles

Current and potential future uses of sorghum to increase nutrient density for human foods.

This review attempts to set forth the current uses and benefits of sorghum ingredients (sorghum syrup, grain, and flour) and implications for future potential uses of sorghum for human consumption. Additionally, this review aims to direct future innovation, research, and development for this grain in all forms, with a particular focus on increasing the nutritional quality of food for human onsumption. Sorghum is an ancient grain that has been underutilized in terms of its nutrient and antioxidant density and functional properties. Sorghum syrup is a sweetener that has a complex flavor profile lending a harmonious balance of sweet and savory in product formulations and provides a lower glycemic index and a higher antioxidant content compared to other commonly used sweeteners. Sorghum syrup has great potential uses within the beverage category, specifically coffee, as a clean-label sweetener with a complex flavor profile. Currently, with growing interest in gluten-free alcohol, specialty brews, and sorghum's shorter growing season compared to barley and wheat, sorghum grain is being used more frequently in alcohol and no- and low-alcohol beverage production. Additionally, sorghum grain is being utilized in products as a non-wheat, nutrient-dense baking grain that has a glycemic index lower than wheat, is high in resistant starch, and contains significantly more antioxidants. Other potential applications for sorghum ingredients include a non-synthetic food dye and a sustainable and biodegradable alternative to plastic films and coatings for foods. Sorghum should be considered an ingredient in product formulation, especially in light of its ability to withstand drought and high temperatures seen in global warming.

Classification of Electronic Waste Components through X-ray and Neutron-Based Imaging Techniques.

In modern society, the amount of e-waste is growing year by year. Waste electronic items are complex, highly heterogeneous systems, containing organic material as well as several exotic, valuable, toxic, mostly metallic elements. In this study, the potential of X-ray and neutron radiography to reveal the inner structure of various complex e-waste was investigated. The images obtained using the two techniques were evaluated together to investigate the possibility of a more efficient segmentation of the individual components. The advantages and limitations of the two methods were identified for the studied waste types. X-ray radiography was found to be preferable for the identification of small metallic parts and for revealing the internal structure of e-waste with thick plastic coatings. Neutron radiography allowed for the identification of several components that did not provide sufficient contrast with X-ray imaging due to their similar X-ray attenuation compared to their surroundings. The combination of the two methods opens up new opportunities and could provide much more effective segmentation than either method alone.

Non-Destructive Testing of Plastic Coatings

Non-Destructive Testing of Plastic Coatings

What smell can tell: using Magic Chemisorbers and GC/MS to capture and analyse volatiles off-gassing from plastic coatings

What smell can tell: using Magic Chemisorbers and GC/MS to capture and analyse volatiles off-gassing from plastic coatings

Electrochemical deposition of coloured Ni/Cu2O bilayer films on large area plastic substrates for decorative applications

ABSTRACT In this study, coloured Ni/Cu2O bilayer films were electrochemically deposited on large area automobile plastic parts (7 × 13 cm) for decorative applications. Such coatings may become an alternative to ubiquitously used Cr coatings for plastics. Purple, dark cyan and gold colours with good homogeneity and high brightness could be produced by tuning the deposition time of the Cu2O layer. Colouration of the bilayer film can be ascribed to interference of light through the metal/dielectric layer, where the thickness of the dielectric layer controls the wavelength of the reflected light. Cu2O film has a compact structure and low roughness, which is essential to obtain uniform colours. Moreover, the Ni/Cu2O bilayer exhibits good adhesion behaviour, environmental stability and enhanced corrosion resistance. This process is industrially viable and enables the large scale production of such decorative coatings.

Thermal lens technique's surrogacy unveiled: A novel tool for microplastic detection and quantification in water

The escalating usage of paper cups and packaging materials with plastic coatings has evolved into a substantial environmental and health concern, evidenced by the report of microplastics in human blood. This research introduces an innovative laser-assisted thermal lens (TL) technique for the precise detection and measurement of microplastics, specifically those leaching from the inner plastic coatings of paper cups. Employing a multipronged approach encompassing scanning electron microscopy, optical microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, UV–visible, and Raman spectroscopy, a comprehensive investigation is conducted into the leaching of microplastics into hot water from paper cups. The thermal diffusivity (D) of water samples containing microplastics is determined using the TL technique based on 120 observations for each temperature conducted using paper cups from three distinct manufacturers. The observation of a strong correlation between the number of microplastic particles (N) and D of the water sample enabled the setting of a linear empirical relation that can be used for computing the microplastics in water at a particular temperature. The study thus proposes a surrogate method for quantifying microplastics in water using the sensitive and non-destructive TL technique.

Polyamide 6 microplastics as carriers led to changes in the fate of bisphenol A and dibutyl phthalate in drinking water distribution systems: The role of adsorption and interfacial partitioning

Microplastics (MPs) co-exist with plastic additives and other emerging pollutants in the drinking water distribution systems (DWDSs). Due to their strong adsorption capacity, MPs may influence the occurrence of additives in DWDSs. The article investigated the occurrence of typical additives bisphenol A (BPA) and dibutyl phthalate (DBP) in DWDSs under the influence of polyamide 6 (PA6) MPs and further discussed the partitioning of BPA/DBP on PA6s, filling a research gap regarding the impact of adsorption between contaminants on their occurrence within DWDSs. In this study, adsorption experiments of BPA/DBP with PA6s and pipe scales were conducted and their interaction mechanisms were investigated. Competitive adsorption experiments of BPA/DBP were also carried out with site energy distribution theory (SEDT) calculations. The results demonstrated that PA6s might contribute to the accumulation of BPA/DBP on pipe scales. The adsorption efficiencies of BPA/DBP with both PA6s and pipe scales were 26.47 and 2.61 times higher than those with only pipe scales. It was noteworthy that BPA had a synergistic effect on the adsorption of DBP on PA6s, resulting in a 26.47 % increase in DBP adsorption. The article provides valuable insights for the compounding effect of different types of additives in water quality monitoring and evaluation.

Influence of plastic shape on interim fragmentation of compostable materials during composting

Common experience with rotting wooden buildings demonstrates that fragmentation is a necessary natural process during biodegradation. In analogy, the loss of structural integrity of biodegradable plastics during biodegradation produces interim microplastic fragments. It is currently not known which parameters govern fragmentation kinetics: chemical structure, physical shape, and composite layers, or composting conditions may all be relevant. Here we investigated the influence of physical shape on the fragmentation of a polyester blend during laboratory tests simulating industrial composting. Methods previously validated on micronized granules as model shape were applied to shapes that better represent consumer products, such as micronized thin films and shredded plastic-coated paper cups. The peak interim number of detected fragments, which are between 3 and 2000 µm, ranked highest for micronized films, lower for micronized plastic granules, and even lower for coated paper cups. The layered structure of polyester on cellulose may thus have stabilized the biodegrading polyester compound against fragmentation. For thin films, fragment counts dissipated with halftime of 2.5 days, and less than 10–8% of the initially added polyester mass was detected in fragments between 3 and 25 µm at the last sampling time point. The physical shape and multilayer structure of the polymer-containing product were found to be decisive for fragmentation kinetics, indicating that tests on micronized polymer granules might not be representative of the release mechanism of fragments from consumer products containing plastic coatings.

Flame Retardant Additives Used for Polyurea-Based Elastomers—A Review

The growing interest in modern polymer materials has targeted research on complex plastic coatings and the possibilities of modifying their features and properties during manufacturing. Today’s modern coatings, including polyurea and polyurethane, are among the most modern developed resins. Compared to other polymer coatings, they are distinguished by their versatility, strength, and durability. They undoubtedly represent the next step in the evolution of coatings. Advances in coating technology have also led to the development of spray, injection, and roto-cast application equipment, improving polyurea-based elastomers’ performance. For many years, there has been much interest in increasing the flame resistance of polymers. This is dictated by safety considerations and the increasing requirements for the flammability of plastics, the area of application of which is growing every year. This text attempts to provide an overview of current research on flame retardant composites. Particular attention was paid to polyurea (PU) and polyurea-based hybrids and the application areas of polyurea coatings. The paper defines flame retardants, discusses how they work, and presents the types of flame retardants and the current trends of their usage in the production of plastics.

Characteristics of novel cycloaliphatic epoxides based on UV-induced cationic ring-opening polymerization for plastic coatings

Cationic ring-opening polymerization (CROP)-capable cycloaliphatic epoxide monomers bearing a benzyl ether group (CE-BEs) were developed as glass-replacement plastic coatings for lightweight automobiles. Three different monomers of bis(((7-oxabicyclo[4,1,0]heptan-3-yl)methoxy)methyl)benzene isomers were synthesized to provide the cycloaliphatic epoxide functional groups. 1H and 13C nuclear magnetic resonance and Fourier transform infrared (FT-IR) spectroscopic analyses confirmed that the monomers were successfully synthesized. The shear viscosity and real-time crosslinking behavior of the CROP coatings were investigated using a rheometer. In particular, the release of thermal energy via CROP under UV irradiation was monitored using differential scanning photocalorimetry. The reaction conversion of cycloaliphatic epoxides by CROP before and after UV irradiation was verified using FT-IR spectroscopy. The transparency of the CROP coating films cured on a polycarbonate substrate was measured using an ultraviolet–visible spectrophotometer, and their adhesion was confirmed using cross-cut tests. For characterization of the surface mechanical properties, a nanoindentation tester and a nanoscratch tester were used in conjunction with an atomic force microscope to evaluate the surface hardness and scratch resistance, respectively. In addition, the thermomechanical properties of the cured CROP coating films were investigated using a rigid-body pendulum tester operated in dynamic physical mode. The ternary coating systems with CE-BEs were found to exhibit high photoreactivity, a dense crosslinking density, a transparent appearance, and enhanced adhesion and mechanical properties, making it suitable for glass-replacement plastic coatings.

Redox Active Zn@MOFs as Spontaneous Reactive Oxygen Species Releasing Antimicrobials.

The rapid development of antimicrobial resistance (AMR) among infectious pathogens has become a major threat and challenge in healthcare systems globally. A strategy distinct from minimizing the overuse of antimicrobials involves the development of novel antimicrobials with a mode of action that prevents the development of AMR microbial strains. Reactive oxygen species (ROS) are formed as a natural byproduct of the cellular aerobic metabolism. However, it becomes pathological when ROS is produced at excessive levels. Exploiting this phenomenon, research on redox-active bactericides has been demonstrated to be beneficial. Materials that release ROS via photodynamic, thermodynamic, and photocatalytic interventions have been developed as nanomedicines and are used in various applications. However, these materials require external stimuli for ROS release to be effective as biocides. In this paper, we report novel zinc-based metal organic framework (Zn@MOF) particles that promote the spontaneous release of active ROS species. The synthesized Zn@MOF spontaneously releases superoxide anions and hydrogen peroxide, exhibiting a potent antimicrobial efficacy against various microbes. Zn@MOF-incorporated plastic films and coatings show excellent, long-lasting antimicrobial potency even under continuous microbial challenge and an aging process. These disinfecting surfaces maintain their antimicrobial properties even after 500× surface wipes. Zn@MOF is also biocompatible and safe on the skin, illustrating its broad potential applications in medical technology and consumer care applications.

Microfluidically Aligned Collagen to Maintain the Phenotype of Tenocytes In Vitro.

Tendon is a highly organized tissue that transmits forces between muscle and bone. The architecture of the extracellular matrix of tendon, predominantly from collagen type I, is important for maintaining tenocyte phenotype and function. Therefore, in repair and regeneration of damaged and diseased tendon tissue, it is crucial to restore the aligned arrangement of the collagen type I fibers of the original matrix. To this end, a novel, user-friendly microfluidic piggyback platform is developed allowing the controlled patterned formation and alignment of collagen fibers simply on the bottom of culture dishes. Rat tenocytes cultured on the micropatterns of aligned fibrous collagen exhibit a more elongated morphology. The cells also show an increased expression of tenogenic markers at the gene and protein level compared to tenocytes cultured on tissue culture plastic or non-fibrillar collagen coatings. Moreover, using imprinted polystyrene replicas of aligned collagen fibers, this work shows that the fibrillar structure of collagen per se affects the tenocyte morphology, whereas the biochemical nature of collagen plays a prominent role in the expression of tenogenic markers. Beyond the controlled provision of aligned collagen, the microfluidic platform can aid in developing more physiologically relevant in vitro models of tendon and its regeneration.

TMBPF-induced neurotoxicity and oxidative stress in zebrafish larvae: impacts on central nervous system development and dopamine neurons

Bisphenol A (BPA), a common bisphenol molecule, is well known in the environment as an endocrine disruptor. Furthermore, BPs (BPA, BPS, BPF, and BPAF) have been shown in recent years to be neurotoxic to zebrafish. Tetramethyl bisphenol F (TMBPF) has recently been introduced as a substitute for bisphenol A (BPA) in various industries, including plastics and food contact coatings. However, a growing number of studies have demonstrated that the toxicity of some BPA substitutes is similar to or even stronger than BPA, posing potential harm to human health and the environment. In this study, we used zebrafish larvae as a model to investigate the neurodevelopmental effects of TMBPF at different concentrations (0, 0.25, 0.5, 1, 2, 4 and 8 mg/L). Our results showed that exposure to TMBPF at concentrations higher than 4 mg/L for 72 h post-fertilization (hpf) resulted in zebrafish mortality, whereas exposure to 2 mg/L for 144 hpf caused deformities. Furthermore, TMBPF exposure inhibited the development of the central nervous system, motor nerves, and dopamine neurons in zebrafish. Real-time polymerase chain reaction (PCR) analysis revealed that TMBPF exposure significantly down-regulated the expression of oxidative stress-related genes (Cu/Zn-SOD, Mn-SOD, and CAT) and neurodevelopmental genes (mbp, gafp, and syn2a), while up-regulated the expression of dopamine-related genes (th1, th2, and dat). Notably, treatment with the antioxidant N-acetylcysteine (NAC) alleviated TMBPF-induced toxicity. NAC can regulate the expression of genes related to oxidative stress, neurodevelopment and dopamine development, and make the nerve development of zebrafish normal. Overall, our research suggested that TMBPF may disrupt the development of the early central nervous system and dopamine neurons, leading to abnormal motor behavior in zebrafish larvae. These results highlight the potential risks associated with the use of TMBPF in various industries and the importance to evaluate its potential risks to human health and the environment.

Study on the performance and application of coatings based on chitosan/gelatin/microbeads composite aerogel

AbstractPlastic reduction regulations have resulted in the gradual replacement of traditional food plastic packaging materials with biodegradable and recyclable paper‐based ones. However, paper is prone to water absorption and moisture damage, and it has poor insulation properties, which can impact food quality and user experience. Recently, biopolymers have gained wide interest as the main substrate for paper coatings, providing various qualities for paper‐based materials to meet food packaging requirements. The coating based on chitosan/gelatin/microbeads composite aerogel prepared in this study not only possesses inherent antimicrobial and preservation properties but also enhances the cardboard's mechanical strength, hydrophobicity, and thermal insulation effect after coating on cardboard. When the coating thickness was 30 μm, the tensile strength of the cardboard was enhanced by 0.65 kN/m, the contact angle increased by 19.3°, and the thermal conductivity coefficient decreased by 0.024 W·m−1·K−1. Therefore, the biopolymer composite coating developed in this study provides an eco‐friendly substitute for plastic coatings on cardboard. In addition to bacteriostatic and preserving freshness, it can also address paper‐based material shortcomings, ensuring food quality and safety with comprehensive packaging protection.

Toxicity of Plastic Additive 1-Hydroxycyclohexyl Phenyl Ketone (1-HCHPK) to Freshwater Microcrustaceans in Natural Water

Various potentially toxic compounds associated with plastic (e.g., plastic additives) can enter the environment during plastic fragmentation and/or weathering. 1-Hydroxycyclohexyl phenyl ketone (1-HCHPK) is a widely used photoinitiator, e.g., in UV-radiation-curable technologies such as 3D-printing, plastic coatings and construction materials. 1-HCHPK may reach aquatic ecosystems via various waste-flows, including leaching from consumer goods. However, knowledge of its potential environmental hazard is scarce. In the present study, we addressed this data gap by assessing the acute and long-term toxicity of 1-HCHPK to freshwater microcrustaceans in environmentally relevant conditions using natural waters. The results showed that the acute toxicity of 1-HCHPK (L(E)C50) to pelagic Thamnocephalus platyurus and Daphnia magna and benthic Heterocypris incongruens ranged between 27 and 55 mg/L. Further, the long-term exposure of D. magna to low levels of 1-HCHPK (0.1 and 1.0 mg/L) did not affect ephippia hatching or organismal fitness, even in three successive daphnid generations. Thus, 1-HCHPK did not pose a hazard to the freshwater microcrustaceans at concentrations < 1 mg/L in the environmentally relevant conditions (i.e., multigenerational life cycle tests conducted in lake water at low chemical exposure concentrations). The tests employed in this study allowed for the environmentally relevant hazard assessment of emerging pollutants such as a plastic additive 1-HCHPK.

Some practical NDE and QC Applications of Time Domain Terahertz Technology

This is an introductory talk, which will briefly discuss the principles of the generation and measurement of terahertz energy, look at its interaction with different materials and show how these principles can be employed to perform inspections of a wide variety of nonconductive materials, including single or multi-layer plastic structures and coatings on both conductive and nonconductive substrates. Terahertz technology, using electromagnetic waves situated between microwaves and the far infra-red, is another ‘tool in the box’ enabling accurate measurement of layer thickness, location of metallic inserts, and detection of discontinuities in materials and configurations that are unsuited for ‘conventional’ inspection approaches. Terahertz investigations are non-harmful, non-contact and normally can be applied from one side of a part. This talk will discuss the applicability of this technology to several practical applications in the aerospace, manufacturing, energy, construction and oil and gas industries. This includes applications where the technology has been implemented into production, and others where it has been investigated, shown to be feasible, but not yet implemented due to external factors. We will also mention its application in several ‘cultural heritage’ investigations. Brief details of equipment used will be discussed and an outline case study showing development of a technique and the accuracy which can be obtained will be presented.

Practical NDE and QC applications of time domain terahertz technology

This is an introductory talk, which will briefly discuss the principles of the generation and measurement of terahertz energy, look at its interaction with different materials and show how these principles can be employed to perform inspections of a wide variety of nonconductive materials, including single or multi-layer plastic structures and coatings on both conductive and nonconductive substrates. Terahertz technology, using electromagnetic waves situated between microwaves and the far infra-red, is another ‘tool in the box’ enabling accurate measurement of layer thickness, location of metallic inserts, and detection of discontinuities in materials and configurations that are unsuited for ‘conventional’ inspection approaches. Terahertz investigations are non-harmful, non-contact and normally can be applied from one side of a part. This talk will discuss the applicability of this technology to several practical applications in the aerospace, manufacturing, energy, construction and oil and gas industries. This includes applications where the technology has been implemented into production, and others where it has been investigated, shown to be feasible, but not yet implemented due to external factors. We will also mention its application in several ‘cultural heritage’ investigations. Brief details of equipment used will be discussed and an outline case study showing development of a technique and the accuracy which can be obtained will be presented.

Dual network interpenetrating degradable waterborne polyurethanes with hydrogen bonded cross‐linked modified β‐cyclodextrin hydrophobic cavities

AbstractThe study gives an investigation on the properties of β‐cyclodextrin (β‐CD) waterborne polyurethane (WPU) composites with cross‐linked network structure and hydrogen bonding system. The polyurethane films modified with β‐CD/PEG exhibit superior thermal stability and biodegradability, it is capable to be applied to bio‐degradable plastic coatings. To improve the distribution of β‐CD in WPU, the β‐CD was modified by three different molecular weights of polyethylene glycol hydrophile (PEG). Since the chain segments and hydrophilic hydroxyl groups of PEG interact with the hydrophobic cavities and edges of β‐CD to form new complexes, thus enhancing the flexibility and structural integrity of WPU chains and conferring better biological properties. The analysis focuses on the changes of thermal stability and biodegradability after modification. The results indicated that the temperature of maximum thermal weight loss rate (Tmax) of β‐CD/PEG/WPU composites reached 394.1°C and the soft segment glass transition temperature (Tg) was −42.4°C after the introduction of β‐CD/PEG. Both are significantly improved compared to WPU, with degradation rates of 31.2% in lipase PBS solution and 14.8% in soil, and can therefore be better applied to current medical devices and biodegradable coatings, as well as other bio‐environmental areas.

Plastic Laminate Antireflective Coatings for Millimeter-Wave Optics in BICEP Array

The BICEP/Keck series of experiments target the cosmic microwave background at degree-scale resolution from the South Pole. Over the next few years, the “Stage-3” BICEP Array (BA) telescope will improve the program’s frequency coverage and sensitivity to primordial B-mode polarization by an order of magnitude. The first receiver in the array, BA1, began observing at 30/40 GHz in early 2020. The next two receivers, BA2 and BA3, are currently being assembled and will map the southern sky at frequencies ranging from 95 to 150 GHz. Common to all BA receivers is a refractive, on-axis, cryogenic optical design that focuses microwave radiation onto a focal plane populated with antenna-coupled bolometers. High-performance antireflective coatings up to 760 mm in aperture are needed for each element in the optical chain, and must withstand repeated thermal cycles down to 4 K. Here, we present the design and fabrication of the 30/40 GHz anti-reflection coatings for the recently deployed BA1 receiver, with indices matched to its various polyethylene, nylon and alumina optical components. We describe an epoxy coating technique designed for alumina optics, which achieves better than 80% transmission at room temperature. For polyethylene optical elements, we present a new heat-compression approach that allows low-density polytetrafluoroethylene AR layers to reach sub-percent reflected power. We describe the planned use of these methods for the next BA cryostats, which may inform technological choices for future small-aperture telescopes of the CMB-S4 experiment.

High-Performance, Degradable, Self-Healing Bio-Based Nanocomposite Coatings with Antibacterial and Antioxidant Properties.

The purpose of this study is to obtain a bio-based coating with good functional activity and self-healing ability, demonstrating its potential in food, materials, and other application fields. Plastic coatings can cause serious environmental pollution. It was a good solution to replace plastic coatings with degradable coatings. However, the development of degradable coatings in the fields of food and materials was limited due to their insufficient antibacterial ability and weak comprehensive properties. Therefore, chitosan nanoparticles (NPs) loaded with gallic acid (GA) were self-assembled with gelatin (GE) to prepare high-performance, degradable, self-healing bio-based nanocomposite coatings with antibacterial and antioxidant properties. The oxygen permeability of GE nanocomposite coatings decreased gradually with the addition of NPs, and the barrier properties increased significantly. At the same time, due to the excellent antioxidant and antibacterial ability of GA, the antioxidant effect of the nanocomposite coatings increased by 119%, and the antibacterial rate against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) increased by 32% and 58%, respectively, compared with the pure GE coatings. In addition, the nanocomposite coatings can be repaired within 24 h after being scratched at room temperature. Finally, GA coated with chitosan nanoparticles can significantly delay the escape of GA, and the retardation of gallic acid release exceeded 89% in simulated solutions after 24 h immersion, extending the service life of the nanocomposite coatings.