Thermoplastic Films Research Articles

Synthesis of Amorphous Cellulose Derivatives via Michael Addition to Hydroxyalkyl Acrylates for Thermoplastic Film Applications

The aim of this study is to prepare new cellulose derivatives that show good feasibility and processability. Accordingly, in this study, we demonstrate Michael addition to hydroxyalkyl acrylates, that is, 2-hydroxyethyl and 4-hydroxybutyl acrylates (HEA and HBA, respectively), to synthesize amorphous cellulose derivatives under alkaline conditions. The reactions were carried out in the presence of LiOH in ionic liquid (1-butyl-2,3-dimethylimidazolium chloride)/N,N-dimethylformamide (DMF) solvents at room temperature or 50 °C for 1 h. The Fourier transform infrared and 1H nuclear magnetic resonance (NMR) measurements of the products supported the progress of Michael addition; however, the degrees of substitution (DS) were not high (0.3–0.6 for HEA and 0.6 for HBA). The powder X-ray diffraction analysis of the products indicated their amorphous nature. The cellulosic Michael adduct from HEA with DS = 0.6 was swollen with high polar organic liquids, such as DMF. In addition to swelling with these liquids, the cellulosic Michael adduct from HBA was soluble in dimethyl sulfoxide (DMSO), leading to its 1H NMR analysis in DMSO-d6. This adduct was found to form a cast film with flexible properties from its DMSO solutions. Furthermore, films containing an ionic liquid, 1-butyl-3-methylimidazolium chloride, showed thermoplasticity. The Michael addition approach to hydroxyalkyl acrylates is quite effective to totally reduce crystallinity, leading to good feasibility and processability in cellulosic materials, even with low DS. In addition, the present thermoplastic films will be applied in practical, bio-based, and eco-friendly fields.

Engineering and modification of physical properties of thermoplastic polymeric films using oxygen ions bombardment for industrial applications

Engineering and modification of physical properties of thermoplastic polymeric films using oxygen ions bombardment for industrial applications

Optimizing Thermoplastic Starch Film with Heteroscedastic Gaussian Processes in Bayesian Experimental Design Framework

The development of thermoplastic starch (TPS) films is crucial for fabricating sustainable and compostable plastics with desirable mechanical properties. However, traditional design of experiments (DOE) methods used in TPS development are often inefficient. They require extensive time and resources while frequently failing to identify optimal material formulations. As an alternative, adaptive experimental design methods based on Bayesian optimization (BO) principles have been recently proposed to streamline material development by iteratively refining experiments based on prior results. However, most implementations are not suited to manage the heteroscedastic noise inherently present in physical experiments. This work introduces a heteroscedastic Gaussian process (HGP) model within the BO framework to account for varying levels of uncertainty in the data, improve the accuracy of the predictions, and increase the overall experimental efficiency. The aim is to find the optimal TPS film composition that maximizes its elongation at break and tensile strength. To demonstrate the effectiveness of this approach, TPS films were prepared by mixing potato starch, distilled water, glycerol as a plasticizer, and acetic acid as a catalyst. After gelation, the mixture was degassed via centrifugation and molded into films, which were dried at room temperature. Tensile tests were conducted according to ASTM D638 standards. After five iterations and 30 experiments, the films containing 4.5 wt% plasticizer and 2.0 wt% starch exhibited the highest elongation at break (M = 96.7%, SD = 5.6%), while the films with 0.5 wt% plasticizer and 7.0 wt% starch demonstrated the highest tensile strength (M = 2.77 MPa, SD = 1.54 MPa). These results demonstrate the potential of the HGP model within a BO framework to improve material development efficiency and performance in TPS film and other potential material formulations.

Novel Forming Shoulder for Coated Paper‐Based Materials With Improved Convertibility and Minimum Wrinkles for Use in Vertical Form, Fill and Seal Machines

ABSTRACTMost vertical form, fill and seal machines use thermoplastic films. However, the gradual shift towards sustainability has created challenges for the packaging industry to employ flexible coated paper‐based materials for packing products. Forming shoulders are a crucial component in packaging machinery for creating coated paper‐based packaging as the size and shape of the packaging depend on their geometrical features. However, the shoulder geometry and design can negatively affect paper packaging by causing unwanted wrinkles and tears, which can affect the shelf lives of products. Therefore, this study focused on developing a new shoulder and optimizing its geometrical parameters for coated paper‐based packaging. Conventional forming shoulders were experimentally investigated by evaluating the influence of their geometrical parameters on flexible coated papers before focusing on optimizing the new shoulder. Additionally, this study aimed to improve the overall runnability and convertibility of the coated paper on the forming shoulder. The newly designed optimized shoulder features an enhanced geometry that can minimize the stress–strain effect. Additionally, the computerized numerical control machined new shoulder features improved web tracking and material handling process. The study achieved to produce lower surface roughness with minimum number of wrinkles on the pillow bag's surface. Furthermore, it ensures that the oil‐ and grease‐resistance properties of the converted coated paper are maintained and feature an enhanced geometry that minimizes the stress–strain effect on paper, thereby offering a more sustainable and efficient packaging solution.

Discovery of a polyurethane-degrading enzyme from the gut bacterium of plastic-eating mealworms

Although numerous polyurethane (PU)-degrading enzymes were identified from a diverse array of microorganisms in soil or compost, it is intriguing to investigate whether novel PU-degrading enzymes can be discovered in other biological environments. This study reports the discovery of an enzyme (MTL) for PU plastic degradation from the bacterial strain Mixta tenebrionis BIT-26, isolated from the gut of plastic-eating mealworms. MTL shows significant degradation activity towards three commercial PU substrates, including Impranil®DLN-SD, thermoplastic films (PEGA-HDI), and thermoset foams (PEGA-TDI), by cleaving the ester bonds in the polyester polyol moieties. The structure, molecular docking, and site-directed mutagenesis analyses elucidate the substrate binding model. A combination of structure-based comparison and mutational studies reveals the underlying architecture of the enzyme's specificity. These findings provide a fresh perspective into understanding plastic metabolism in the gut of plastic-eating insects and a prospective path for developing a biodegradation technique for plastic waste disposal.

Compression Molding of Low-Density Polyethylene Matrix/Glass-Fiber-Reinforced Thick Laminates.

Thermoplastic fiberglass was compression molded in the form of thick panels with a nominal thickness of 10 mm and a size of 300 × 300 mm2. A simplified procedure was adopted to speed up the lamination procedure and adapt it to the aim of recycling waste, glass fibers, fabrics, and thermoplastic films. Low density polyethylene was used as a matrix to simplify the laboratory process, but the same procedure can be extended to other thermoplastic film, such as polyamide. The final thermoplastic composite shows unique properties in terms of its repairability, and its performance was improved by increasing the number of repairing repetitions. For this aim, a repairability test was designed in the bending configuration, and three consecutive cycles of bending/repairing/bending were carried out. The static mechanical properties of the final thermoplastic composite were, conversely, low in comparison with traditional fiberglass because of the choice of a polyethylene matrix. The bending tests showed that the maximum strength was lower than 10 MPa and the elastic modulus was less than 1 GPa. Nevertheless, the toughness of the thermoplastic composite was high, and the samples continued to deform under bending without splitting into two halves.

Development of thermoplastic films via formulation design technology for millimeter-wave communication applications

Development of thermoplastic films via formulation design technology for millimeter-wave communication applications

Production of Thermoplastic Starch-Aloe Vera Gel Film Embedded with Polyethylene for Improved Tensile Strength and Water Absorption

The water absorption characteristics of thermoplastic starch (TPS) reveal its ability to interact with and absorb water, influencing its overall performance in various applications. The introduction of aloe vera (AV) gel into the TPS polymeric matrix film has proven beneficial in enhancing tensile strength but a notable deficiency is observed in lowering water absorption percentage. Therefore, this paper aims to reduce the water absorption of the TPS30AV polymer matrix film by utilizing polyethylene (PE) without reducing the tensile strength performance of the TPS30AV film. The TPS30AV film was produced using melt-blending and hot-press techniques. Six samples were presented consisting of a control film (TPS30AV) and TPS30AV film with different concentrations of PE resins (5%, 10%, 20%, 30%, and 40%). The film's performance was assessed by examining its mechanical properties, water absorption, and water solubility. The finding shows that TPS30AV with 40% PE has the highest improvement in water absorption percentage which reduces from 309.86% to 34.16% but a tremendous decrement in tensile strength performance. However, TPS30AV with 10% PE has the highest tensile strength, 9.65 MPa with a 20.99% improvement in water absorption reduction. The properties obtained for TPS30AV10PE were also good inYoung's modulus and water solubility percentage. It shows that the film formulated is comparable with previous studies, and improvement has been achieved. As a conclusion, adding PE improved the polymeric structure of TPS30AV and can be used as a biodegradable food-packaging film.

Development of stopped-flow hyper-CEST NMR method on recirculating hyperpolarization system as applied to void space analysis in polymers.

129Xe NMR spectroscopy of polymers can provide important information on void spaces, sometimes called free volume, in polymers. Unfortunately, the spectroscopy's low sensitivity has limited its widespread use in both academic and industrial research. In order to overcome such a difficult situation, hyper-CEST method which employs hyperpolarization and CEST techniques, is examined after the introduction of recirculation and subtraction modes. Alongside the incorporated stopped-flow technique, these modes were very efficient in detecting very weak hidden signals from cellulose nanofiber (CNF) and silk fibroin (SF) films and in discussing the void space in these polymers. From the analysis of detailed saturation frequency dependence in the increment of 100Hz, the chemical shifts of hidden peaks were successfully determined to give reasonable values for the size of void space in CNF and SF. Application on thermoplastic polyurethane film also supported our method of analysis. The subtraction mode was very efficient in judging the presence or absence of any peak at a fixed saturation frequency. These facts support that the mode will surely be useful in the future exploratory study of very weak hidden signals.

The Hydrogen Bonding in the Hard Domains of the Siloxane Polyurea Copolymer Elastomers.

For probing the structure-property relationships of the polyurea elastomers, we synthesize the siloxane polyurea copolymer elastomer by using two aminopropyl-terminated polysiloxane monomers with low and high number-average molecular weight (Mn), i.e., L-30D and H-130D. To study the influence of the copolymer structures on the film properties, these films are analyzed to obtain the tensile performance, UV-vis spectra, cross-sectional topographies, and glass transition temperature (Tg). The two synthetic thermoplastic elastomer films are characterized by transparency, ductility, and the Tg of the hard domains, depending on the reacting compositions. Furthermore, the film elasticity behavior is studied by the strain recovery and cyclic tensile test, and then, the linear fitting of the tensile data is used to describe the film elasticity based on the Mooney-Rivlin model. Moreover, the temperature-dependent infrared (IR) spectra during heating and cooling are conducted to study the strength and recovery rate of the hydrogen bonding, respectively, and their influence on the film performance is further analyzed; the calculated Mn of the hard segment chains is correlated to the macroscopic recovery rate of the hydrogen bonding. These results can add deep insight to the structure-property relationships of the siloxane polyurea copolymer.

An electropermanent magnet valve for the onboard control of multi-degree of freedom pneumatic soft robots

To achieve coordinated functions, fluidic soft robots typically rely on multiple input lines for the independent inflation and deflation of each actuator. Fluidic actuators are controlled by rigid electronic pneumatic valves, restricting the mobility and compliance of the soft robot. Recent developments in soft valve designs have shown the potential to achieve a more integrated robotic system, but are limited by high energy consumption and slow response time. In this work, we present an electropermanent magnet (EPM) valve for electronic control of pneumatic soft actuators that is activated through microsecond electronic pulses. The valve incorporates a thin channel made from thermoplastic films. The proposed valve (3 × 3 × 0.8 cm, 2.9 g) can block pressure up to 146 kPa and negative pressures up to –100 kPa with a response time of less than 1 s. Using the EPM valves, we demonstrate the ability to switch between multiple operation sequences in real time through the control of a six-DoF robot capable of grasping and hopping with a single pressure input. Our proposed onboard control strategy simplifies the operation of multi-pressure systems, enabling the development of dynamically programmable soft fluid-driven robots that are versatile in responding to different tasks.

Secondary cleft palate correction with 3D-printed thermoplastic polyurethane film – a case report

Cleft palate is an oronasal communication that can affect the area comprehending the lips and the soft palate. Its clinical signs vary depending on the degree of the defect and the age of the animal, ranging from nasal secretion, coughing, sneezing, halitosis, respiratory difficulty, aspiration pneumonia, and loss of body condition. Its diagnosis is based on inspection of the oral cavity and imaging tests. Palatal defects must be surgically corrected as quickly as possible, using mucosal flaps, grafts, or implants. A desire to evolve alternative treatments for cleft palates drives the search for ways to manufacture customized pieces. 3D printing and biomaterials have enhanced in detail and applicability; combined with design tools and imaging exams, they allow for the making of precise implants and anatomical models for the planning and execution of surgical procedures. This report describes the case of a female, mixed-breed feline treated at a veterinary clinic; it was diagnosed with secondary cleft palate, had a history of falling, and underwent previous palatoplasties with recurrence. A surgical reintervention was performed to implant a 3D-printed TPU film to close its secondary cleft palate.

Effect of Glycerol and Sisal Nanofiber Content on the Tensile Properties of Corn Starch/Sisal Nanofiber Films.

Currently, petroleum-derived plastics are widely used despite the disadvantage of their long degradation time. Natural polymers, however, can be used as alternatives to overcome this obstacle, particularly cornstarch. The tensile properties of cornstarch films can be improved by adding plant-derived nanofibers. Sisal (Agave sisalana), a very common low-cost species in Brazil, can be used to obtain plant nanofibers. The goal of this study was to obtain sisal nanofibers using low concentrations of sulfuric acid to produce thermoplastic starch nanocomposite films. The films were produced by a casting technique using commercial corn starch, glycerol, and sisal nanofibers, accomplished by acid hydrolysis. The effects of glycerol and sisal nanofiber content on the tensile mechanical properties of the nanocomposites were investigated. Transmission electron microscopy findings demonstrated that the lowest concentration of sulfuric acid produced fibers with nanometric dimensions related to the concentrations used. X-ray diffraction revealed that the untreated fibers and fibers subjected to acid hydrolysis exhibited a crystallinity index of 61.06 and 84.44%, respectively. When the glycerol and nanofiber contents were 28 and 1%, respectively, the tensile stress and elongation were 8.02 MPa and 3.4%. In general, nanocomposites reinforced with sisal nanofibers showed lower tensile stress and higher elongation than matrices without nanofibers did. These results were attributed to the inefficient dispersion of the nanofibers in the polymer matrix. Our findings demonstrate the potential of corn starch nanocomposite films in the packaging industry.

Design of interconnected graphene loaded thermoplastic elastomeric blend composite films for minimizing electromagnetic radiation and efficient heat management

AbstractIn this work, electrically conductive thermoplastic elastomeric blend composite films based on polystyrene (PS)/ethylene‐co‐methyl acrylate (EMA) filled with functionalized graphene were developed via the solution mixing technique. Morphological analysis revealed that selective localization of amine‐functionalized reduced graphene oxide (G‐ODA) sheets in the EMA phase of co‐continuous binary blend formed a well‐connected dense conductive pathway by graphene sheets ultimately facilitating the double percolation phenomenon. The electrical percolation threshold was achieved at ~2 wt% of G‐ODA loading which was much lower than that for both single polymer composites. An electrical conductivity of 0.9 S/cm was obtained for blend composite film with 10 wt% of graphene concentration whereas for the same filler loading, PS and EMA composites exhibited electrical conductivity of 1.9 × 10−1 and 2.3 × 10−1 S/cm, respectively. The obtained thermal conductivity of the blend composite with 10 wt% of G‐ODA loading was 0.95 W/m K with 400% enhancement compared to the neat blend system. The same composite exhibited increased real and imaginary permittivity of 92 and 83, respectively. The electrical percolation threshold is well‐correlated with the percolation concentration found from storage modulus and thermal conductivity data. The fabricated PS/EMA blend composite film exhibited absorption‐dominant electromagnetic interference SE of −25 and − 35 dB in X‐band frequency (8.2–12.4 GHz) for 10 wt% of graphene loading with a sample thickness of 0.5 and 1 mm, respectively.

Characterization of mechanical, thermal and rheological properties of silica-based nanocomposite filled thermoplastic polyurethane film

Characterization of mechanical, thermal and rheological properties of silica-based nanocomposite filled thermoplastic polyurethane film

Thermal Stability of Encapsulated Carbon-Based Multiporous-Layered-Electrode Perovskite Solar Cells Extended to Over 5000 h at 85 °C.

The key to the practical application of organometal-halide crystals perovskite solar cells (PSCs) is to achieve thermal stability through robust encapsulation. This paper presents a method to significantly extend the thermal stability lifetime of perovskite solar cells to over 5000 h at 85 °C by demonstrating an optimal combination of encapsulation methods and perovskite composition for carbon-based multiporous-layered-electrode (MPLE)-PSCs. We fabricated four types of MPLE-PSCs using two encapsulation structures (over- and side-sealing with thermoplastic resin films) and two perovskite compositions ((5-AVA)x(methylammonium (MA))1-xPbI3 and (formamidinium (FA))0.9Cs0.1PbI3), and analyzed the 85 °C thermal stability followed by the ISOS-D-2 protocol. Without encapsulation, FA0.9Cs0.1PbI3 exhibited higher thermal stability than (5-AVA)x(MA)1-xPbI3. However, encapsulation reversed the phenomenon (that of (5-AVA)x(MA)1-xPbI3 became stronger). The combination of the (5-AVA)x(MA)1-xPbI3 perovskite absorber and over-sealing encapsulation effectively suppressed the thermal degradation, resulting in a PCE value of 91.2% of the initial value after 5072 h. On the other hand, another combination (side-sealing on (5-AVA)x(MA)1-xPbI3 and over- and side-sealing on FA0.9Cs0.1PbI3) resulted in decreased stability. The FACs-based perovskite was decomposed from these degradation mechanisms by the condensation reaction between FA and carbon. For side-sealing, the space between the cell and the encapsulant was estimated to contain approximately 1,260,000 times more H2O than in over-sealing, which catalyzed the degradation of the perovskite crystals. Our results demonstrate that MA-based PSCs, which are generally considered to be thermally sensitive, can significantly extend their thermal stability after proper encapsulation. Therefore, we emphasize that finding the appropriate combination of encapsulation technique and perovskite composition is quite important to achieve further device stability.

Effect of graphene nanoplatelets and nano zinc oxide on gas barrier and antibacterial properties of thermoplastic nanocomposites

AbstractGraphene‐loaded thermoplastic nanocomposite films must be evaluated for antibacterial activity, mechanical, and barrier properties before being utilized as food packaging. Herein, economically feasible linear low‐density polyethylene (LLDPE)‐based flexible packaging materials were developed via the melt compounding technique at 170°C temperature by taking advantage of both graphene nanoplatelets (GNP) and nano zinc oxide (ZnO) fillers. Morphological studies reveal that in composites loaded with GNP/ZnO hybrid fillers, ZnO nanoparticles form a network‐like structure throughout the polymer matrix. Simultaneously, GNPs are uniformly dispersed. The inclusion of hybrid nanofiller considerably reduces both the oxygen transmission rate and the water vapor transmission rate (WVTR) in LLDPE nanocomposites. A maximum decrease of 36% and 67%, respectively, in both oxygen transmission rate and WVTR is observed for 3 wt% of hybrid filler loading in a thermoplastic matrix containing 1 wt% of nano ZnO. The antibacterial efficacy of the derived nanocomposite films is obvious against gram‐positive (Bacillus subtilis) and gram‐negative (Escherichia coli) bacterial strains. These nanocomposite films have the potential to be successfully utilized as flexible packaging materials owing to their improved thermal, barrier, and antibacterial effectiveness.Highlights GNP/ZnO was used as a hybrid reinforcing filler in the LLDPE matrix. ZnO nanoparticles establish a network‐like morphology. LLDPE nanocomposite films exhibited excellent antibacterial activity. Oxygen and water vapor barrier properties were significantly improved. The thermoplastic composite films could be used as food packaging materials.

Fracture toughness and failure behavior of CF/epoxy composites interleaved with melt‐infused PET, PEI, and PEEK film

AbstractThis study investigates the effect of incorporating polyethylene terephthalate (PET), polyetherimide (PEI), and polyether‐ether‐ketone (PEEK) thermoplastic films in melt form as interlayers to toughen carbon fiber/epoxy composites. The addition of melt‐infused PET, PEI, and PEEK film into carbon fiber/epoxy composite enhanced the mode‐I interlaminar fracture toughness (ILFT) by 60%, 156%, and 284%, respectively. The primary toughening mechanisms found were plastic deformation and mechanical interlocking through fiber bridging, which left fiber imprint traces on the fracture surface. The mode‐II ILFT of PET, PEI, and PEEK film interleaved laminates was improved by 80%, 188%, and 96%, respectively. Plastic deformation was observed to be the principal toughening mechanism. Notably, these enhancements in ILFT were achieved while simultaneously increasing interlaminar shear strength. These findings show the role of hot‐melt‐infused PET, PEI, and PEEK thermoplastic films in the improvement of ILFT of composites which is crucial in the design of damage‐tolerant composite structures.Highlights Composites were interleaved with PET, PEI, and PEEK films via melt‐infusion. Mode‐I and mode‐II ILFT were significantly enhanced, up to 284% for PEEK. Failure exhibited plastic deformation, extensive fiber bridging, and pull‐out. Melt‐infusion created complex, mechanically interlocked interfaces.

Flexible monolayer films of poly(lactic acid)/gallic acid for active food packaging: Preparation, characterization, and bioactive properties

AbstractThe design of eco‐friendly active food packaging systems based on biobased polymeric materials is a growing field of research because of the pressing concern for sustainable development. Herein, monolayer ternary thermoplastic films composed of poly(lactic acid) (PLA), gallic acid (GA, 2.5% w/w relative to PLA), and a plasticizer (poly(ethylene glycol) [PEG] or epoxidized linseed oil [ELO], 5.0 and 7.5% w/w relative to PLA) are prepared via melt‐mixing followed by compression molding. The ensuing plasticized and self‐standing PLA/GA films are translucent and have good mechanical properties (Young's modulus ~2 GPa) and welding performance. The incorporation of GA yields films with ultraviolet‐light barrier properties (transmittance below 40%, 200–400 nm), antioxidant capacity (radical scavenging activity above 94%), and antibacterial activity against the methicillin‐resistant strain of Staphylococcus aureus (minimum of 3‐log reduction colony forming units mL−1). These thermoplastic films are easily degradable via enzymatic degradation with proteinase K from Tritirachium album, reaching weight loss values of 100% after 9 days. The films plasticized with PEG present slightly better antibacterial action and enzymatic degradation, whereas those plasticized with ELO exhibit marginally higher surface hydrophobicity and thermal stability. Thus, the combination between PLA and GA yielded biobased films with bioactive properties that have potential for application in active food packaging.

Discontinuous interleaving strategies for toughening, damage sensing and repair in multifunctional carbon fibre/epoxy composites

Thermoplastic interleaving is a well-established approach to toughen carbon fibre thermoset laminates, studied over the past five decades. Recently, it has been revisited to create functional smart composites with damage sensing and repair capabilities with a renewed focus on the sustainability and longevity of components. However, the introduction of thermoplastic films within the interlaminar region often lowers fibre volume fraction and performance at elevated temperature, while the addition of impermeable continuous films during manufacture may also limit compatible fabrication methods. Moreover, the incorporation of dielectric thermoplastic films inevitably reduces through-thickness electrical conductivity and prevents accurate damage sensing of delamination in carbon fibre laminates. In this study, strategies of using discontinuous interleaving to improve both fracture toughness and thermomechanical properties of carbon fibre epoxy laminates, with the ability to monitor delamination damage and restore mechanical properties after a short healing step have been explored. Both the interleaving design and the physical properties of the thermoplastic were assessed, which has not been addressed previously. Interleaving high molecular weight thermoplastic with decreasing interleaf width and distance between interleaf zones results in increased fracture toughness (+347 %), by creating a superior toughened interlaminar zone, forcing a migration of delamination into the intralaminar region. A repair efficiency of 77 % was achieved when using a lower molecular weight of thermoplastic; however, the lack of thermoplastic over the entire fracture surface area affects the repairing performance universally. Damage sensing and thermomechanical properties were significantly improved compared to continuous interleaving, demonstrating that discontinuous thermoplastic interleaving strategies offer a favourable combination of toughening, thermal performance and accurate damage sensing for multifunctional high-performance composites.