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In this paper, geopolymer composite bricks were prepared using polyethylene terephthalate (PET) waste and the influence of PET amount, curing conditions, and durability were investigated, providing valuable insights for developing environmentally friendly building materials. Notably, there is a significant increase of 56% in compressive strength as the temperature rises from 30 °C to 70 °C. The presence of PET waste increases water absorption, which is positively correlated with thermal conductivity by 39%. Additionally, there is a negative correlation of 42% between water absorption and average compressive strength. The use of scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) reveals the presence of voids, fractures, and changes in the composition of the material at a microscopic level. Significantly, substituting PET waste ranging from 0 to 100% enhances thermal conductivity by up to 25%. The use of a clustering algorithm-based analysis highlights the relationship between microstructure and mechanical properties, of fundamental importance for improving geopolymer composite formulations. The results provide crucial information to predict and study the properties of geopolymer composite bricks, highlighting their ability to solve environmental issues in the building materials. [ABSTRACT FROM AUTHOR]

Liquid crystal polymers (LCP) and polytetrafluoroethylene (PTFE) were in situ fibrillated to produce polyethylene terephthalate (PET)/LCP/PTFE composites using a simple and scalable extrusion drawing techniques. The PET/LCP/PTFE composites included high-aspect-ratio PTFE fibrils and rod-like LCP fibrils. The simultaneous in situ fibrillation of LCP and PTFE exerted synergistic effects on crystalline behaviour and viscosity of PET, especially for mechanical properties of PET and its foam. The tensile strength of PET/LCP/PTFE composites and impact strength representing improvements of 34% and 62% over those of PET. The improved mechanical properties can be attributed to the simultaneous abundance of orienting rod-like rigid LCP fibrils and tangling flexible PTFE fibrils in the PET matrix, which contributed to stress transfer from matrix to fibrils. A simultaneously in situ fibrillated PET/LCP/PTFE composite foam was fabricated using a batch foaming system with supercritical CO2 as blowing agent. The cell diameter of this foam decreased by 23% over that of standard PET foam, while its cell density increased twofold. The smaller cell diameter of PET/LCP/PTFE foam and superior mechanical properties of PET matrix collectively led to the good mechanical properties of PET/LCP/PTFE foam. Specifically, the compressive strength of the PET/LCP/PTFE foam represents a 35% increase over that of PET foam. [ABSTRACT FROM AUTHOR]

This article investigates the thermal, mechanical, and shape memory performances of 3D-printed polylactic acid (PLA), polyethylene terephthalate glycol (PETG), and their blends for potential applications in 4D printing. Differential Scanning Calorimetry reveals distinct glass transition temperatures for PLA-PETG blends, confirming their immiscibility. The integration of PETG alters the crystalline structure of PLA, shifting its behavior from brittle to ductile. This confirms PETG's function as an effective plasticizer. The tensile strength and Young's modulus are influenced by material composition and printing orientation. The results show that 75% PLA and 25% PETG blend demonstrated enhanced mechanical properties compared to other polymer blends. Shape memory experiments demonstrate exceptional fixity and recovery rates, reaching 100%, with the 75% PLA blend exhibiting outstanding performance across 15 cycles. These findings, coupled with insights into the impact of programming temperature, offer valuable perspectives for designing 4D-printed structures with shape memory attributes, unlocking innovative applications across diverse fields. [ABSTRACT FROM AUTHOR]

SiNx thin films have garnered attention as promising barrier films, primarily due to their low impurity diffusion rates, making them suitable for various technological applications. Despite their potential, these films face challenges because they are prone to degradation in hostile environments. This study investigated the oxidation behavior of SiNx thin films, particularly when deposited on two different types of substrates: rigid silicon (Si) and flexible polyethylene terephthalate (PET) films. A thorough microstructural analysis of the SiNx films reveals their detailed morphological and compositional characteristics, enabling a comparison between the SiNx/Si and SiNx/PET films. This study further investigates the impacts of high-temperature and humidity exposure on SiNx thin films, systematically elucidating the degradation behaviors and underlying mechanisms. The structural evolution during SiNx film oxidation is illustrated at the nanoscale, and the factors contributing to the oxidation were analyzed. This study deepens our understanding of the interplay between oxidation processes and the unique environmental conditions of substrates, offering insights into enhancing the stability and reliability of these materials. [ABSTRACT FROM AUTHOR]

Several researchers have recently worked to create sustainable building materials. One of the fundamental prerequisites for sustainable construction methods and environmental impact assessments is the use of green building materials and manufacturing processes. In this research study, geopolymer bricks were developed using polyethylene terephthalate waste and different industrial by-products (rice husk ash, ground granulated blast furnace slag, red mud, construction, and demolition waste) and investigated their performances. The polyethylene terephthalate waste was used as a replacement for sand filler in the geopolymer brick up to 100%. Key findings include a workability decrease of 14.75% and a compressive strength reduction of up to 75% with 100% plastic waste replacement, attributed to increased voids and weak geopolymer matrix interaction. Dry density consistently decreases, and water absorption rises to 13.73% with full sand replacement, indicating a porous structure. Impact resistance improves with plastic waste inclusion, enhancing ductility and thermal conductivity by 57% at full replacement. Microstructural analyses reveal correlations between physical–mechanical properties and changes in porosity, microcracks, and bond strength. Machine learning, especially linear regression, proves effective for strength parameter prediction (up to 100% efficacy, R-square of 0.998). The promising results obtained could offer a substantial environmentally friendly solution to the building and construction industry in line with Circular Economy principles. [ABSTRACT FROM AUTHOR]

There is growing interest in the application of 3D printing for demanding environments subject to gamma radiation in areas such as the nuclear industry and space exploration. In this work, the effect of gamma radiation on fused deposition modelled 3D printed parts composed of polyethylene terephthalate glycol (PETG) and acrylic styrene acrylonitrile (ASA) polymers was studied. Dose levels of up to 2.25 MGy were applied to the printed components, doses equivalent to over 1 year operating near spent nuclear fuel cells. Infrared spectroscopy showed the evidence of cross-linking by the formation of peaks corresponding to –OH and C–H bonds. Tensile and hardness testing was used to assess changes in mechanical properties and showed a reduction in ultimate tensile stress and maximum strain in parts made from both polymers, but with PETG retaining greater strength and ductility than ASA, especially at intermediate gamma exposure. Young's modulus and hardness showed either modest increases or a fairly flat response with exposure. Mechanical properties were heavily dependent on the build structure, with horizontal build samples pulled parallel to the filament direction being several times stronger than vertical build samples pulled normal to the layers. Non-irradiated samples pulled parallel to the filament direction were indicative of ductile failure, with rough surfaces, distinct infill and wall regions and evidence of thinning occurring after fracture, but irradiated fracture surfaces were flatter, smoother and without local thinning, suggesting gamma radiation-induced embrittlement in the material. For samples pulled perpendicular to the filament direction, all fractures occurred between layers, creating flat fracture surfaces with no evidence of necking and indicative of brittle failure regardless of whether the samples were irradiated. [ABSTRACT FROM AUTHOR]

PET (polyethylene terephthalate) being widely used in the manufacturing of bottles, especially in the beverages industry, has obvious advantages over glass bottles and cans, including but not limited to its transparency, robustness, and light weightiness, etc. However, its permeability is a major concern for scientists as it evidently affects the quality of packaged food, especially beverages. The fact that it easily allows gases like oxygen and carbon dioxide to pass through them makes it less effective and least cost-efficient when compared with its substitutes. Alternatively, if its permeability is ameliorated, this can drastically improve the overall statistics of profits in the beverage industry. This paper attempts to improve the gas barrier property of PET via a reduction in carbon dioxide (CO2) permeation. Through temperature-induced solution processing, WS2 (tungsten disulfide) is disseminated in PET. The decrease in CO2 permeability in WS2 nanosheets/PET composites is assessed. After an 11-h test run, free-standing composite membranes demonstrated a maximum 99.9% permeability decrease at extremely low filler loading (0.005 wt% WS2) in contrast to the polymer. It is interesting to note that WS2 loading over 0.005 wt% completely reduced permeation. High-aspect-ratio WS2, homogenous dispersion inside PET, and jiggling effect surrounding nanosheets per flake have all contributed to the gas flow's winding path's complexity. Through the use of models developed by Bharadwaj, Neilson, Lape, and Cussler, experimental findings have been confirmed. SEM evaluates the dispersion state, and X-ray diffraction has validated the formation of composites. Higher mechanical resilience of WS2 nanosheets/PET composites and adhesion property was demonstrated by tensile testing and tribology technique. [ABSTRACT FROM AUTHOR]

The study was based on surface functionalization of conductive PANI (polyaniline) polymer for drug delivery systems. Specifically, an electrochemical polymerization technique was performed for the synthesis of PANI layers on tin-doped indium oxide (In2O3:Sn or ITO)-coated PET (polyethylene terephthalate) substrates. Three main factors were studied: binding ability, drug-loading ability and drug-delivering ability. PANI layers, combined with active carbon (AC), were organized as biomaterials to carry the anticancer drug doxorubicin (DOX). Two different films, PANI and PANI with AC, were polymerized in the emeraldine salt form of PANI. A comparison of the two samples proved that AC molecules enabled DOX molecules to bind to the PANI surface, as observed by the UV–Vis absorption spectra of the films. DOX molecules were detected by UV–Vis spectra with an absorption peak at 547 nm. Findings from drug loading/release tests and in vitro cytotoxicity results confirm that these films can be used as drug delivery systems. This work underlines essential role of AC in the PANI layer for drug delivery. [ABSTRACT FROM AUTHOR]

Ammonia being a major environmental pollutant, the regulation and its specific detection are tremendously important. To meet the urgency, the present article brings out a cost-effective, easy handling and enduring material of reduced graphene oxide (rGO)-doped polyaniline (PANI). Attempting an in situ chemical oxidation technique, thin films of this material were prepared on polyethylene terephthalate substrates at different doping percentages of rGO, varying between 0 and 10%. Furthermore, during the synthesis, various amount of hydrochloric acid (HCl) was dissolved within the precursor solution to achieve different acid molar concentration ranging between 0.1 (M) and 2 (M). Structural and compositional analysis of the materials was performed with X-ray diffraction. Three different spectroscopic studies, Fourier transform infrared (FTIR), Raman and ultraviolet–visible (UV–VIS) spectroscopy, were further carried out to analyse the chemical bond, vibrational modes and band gap, respectively. In addition, the surface morphology of the thin films was examined with field emission scanning electron microscopy (FESEM). To know the accurate size of the PANI and rGO, high-resolution transmission electron microscopy (HRTEM) was conducted. The study of ammonia (NH3) sensing in the domain of 50 ppb to 80 ppm exhibits lucrative sensitivity (~ 486% @ 80 ppm and 33% @ 50 ppb) at room temperature (25 °C), outstanding repeatability in the response curves, well-fitted response curve with the power-law (P ~ 0.71), much faster response/recovery times (tres/trec = 2.1 s/57.1 s @ 80 ppm and 3.7 s/112.9 s @ 50 ppb) and incomparably high selectivity towards NH3. The rGO doping variation, and HCl molarity variation, yield that all of the aforementioned supremacy data have been exhibited by 1% PANI-rGO sample synthesised in 1(M) HCl concentration. The frequency dependence of the sample impedance was studied using impedance spectroscopy in the wide frequency range. Density functional theory calculations were also performed to understand the charge transfer mechanism, adsorption strength, and recovery time for NH3 adsorbed rGO, PANI and rGO-PANI heterostructure. The significant charge transfer and formation of the interfacial electric field explained the importance of the rGO-PANI interface in NH3 sensing. [ABSTRACT FROM AUTHOR]

Flexible perovskite solar cells were potential photovoltaic technologies for achieving wearable power sources with excellent power conversion efficiency (PCE) and continuous roll-to-roll processability. However, the inherent fragile property and poor crystallinity of perovskite films on flexible substrates leaded to inferior photovoltaic performance, which impeded their application in wearable devices. Herein, a biodegradable polymer macromolecule, poly(D, L-lactide) (PDLLA), was doped into perovskite precursor solution to prepare perovskite films with favorable bendable and stretchable properties as well as the corresponding flexible PSCs. Extensive theoretical calculations and experimental analysis unraveled that the carbonyl (C = O) groups of PDLLA cross-linkers and undercoordinated Pb2+ defect sites of perovskite films were chemically coupled through C = O···Pb coordination bond and the hydroxyl (O–H) groups at the end of PDLLA molecules anchored perovskite via O–H···I hydrogen bonding interaction. The strong chemical interactions could govern perovskite crystallization to modulate the films morphology, thus prompting the photovoltaic performance of PSCs. Furthermore, this cross-linking structure was instrumental in suppressing perovskite grain boundaries defects to minimize nonradiative recombination and advancing the film flexibility to enhance environmental and mechanical stability of the devices. Consequently, the optimized devices were fabricated in open-air conditions with desirable efficiencies of 18.94% on a rigid substrate and 16.61% on the corresponding flexible substrate. Since the strong chemical interaction between PDLLA additives and perovskites, the as-fabricated flexible devices assembled on the PET/ITO substrate exhibited favorable bending property, retaining 92.1% of the initial PCE after 2000 bending cycles within a bending radius of 2 mm, suggesting the benign mechanical stability of PSCs. This provided a guide for improving the flexibility of perovskite films for the purpose of the realization of the wearable electronic device. PDLLA accumulated at the grain boundary regions cross-links the neighboring perovskite crystals via C = O···Pb coordination bond and O–H···I hydrogen bonding interaction. The suitable molecular chemical chelation can simultaneously coordinate the defects accumulated at the grain boundaries and suppress the ion migration to optimize the photovoltaic performance and the mechanical stability. [ABSTRACT FROM AUTHOR]

Flexible and ultrathin pressure sensors have received significant attention in applications of health monitoring, artificial skin, human–machine interfaces, soft robotics, etc. Bacterial cellulose (BC) is a renewable resource widely used in tissue engineering and flexible pressure sensors owing to its excellent biocompatibility. In this study, after simple mixing (mass ratio 1:1) and freeze-drying of BC and silver nanowires (AgNWs) suspensions, cylindrical BC-AgNWs aerogels (ф = 14 mm, h = 1.6 mm) were obtained. The BC-AgNWs aerogels showed a porous and fluffy structure with an ultralight mass of 3.2 mg. After compression, ultrathin (30 μm) BC-AgNWs films could be easily fabricated. The BC-AgNWs films had excellent mechanical properties and an ultrahigh sensitivity of 47.1 mA kPa−1 V−1. Ultrathin (~ 40 μm) flexible pressure sensors were assembled by encapsulating the BC-AgNWs films between 1-μm-thick polyethylene terephthalate (PET) films. The assembled PET/BC-AgNWs film/PET pressure sensors had a detection limit of 400 Pa and a fast response time of 220 ms. Moreover, the sensors were used to detect human motions such as finger bending, wrist bending, elbow bending, finger pressing, swallowing, and squatting, showing good application prospects in the field of health monitoring. [ABSTRACT FROM AUTHOR]

Recently, dielectric/metal/dielectric (DMD) transparent electrodes based on MoO3 have been applied in solar cells and organic light emitting diodes, by virtue of the favourable properties of MoO3 as hole-transport/hole-injection material. However, amorphous MoO3 layers are easily dissolved in water, thus inhibiting device processing with water-based solutions. To improve the stability in water, the present study introduces DMD electrodes based on mixed molybdenum–titanium–oxide (MTO), fabricated by DC magnetron sputtering from a conductive oxide target. It is demonstrated that the addition of Ti strongly increases the stability in water, while the desirable electronic properties of MoO3, specifically the high work function and wide bandgap, are maintained. The DMD electrodes, with Ag as metal layer, were fabricated on both rigid and flexible substrates, namely glass and polyethylene terephthalate (PET). The obtained electrodes have low sheet resistance around 5 Ω/sq and high average visible transmittance well above 0.7 (including the substrate). As a result of the MTO stability, processing with water-based solutions takes place without electrode degradation. To demonstrate the process compatibility for large-scale, industrial production, the DMDs were sputter-deposited by a roll-to-roll process on a 300 mm-wide PET foil, achieving similar electrode properties with the laboratory-scale samples. [ABSTRACT FROM AUTHOR]

Perhydropolysilazane (PHPS) forms a thin layer by solution processing and converts to dense glass-like silica (SiOx) with excellent chemical resistance, adhesion, and optical properties. However, heat treatment methods for the conversion of PHPS into SiOx are not sufficient for its application to functional polymer films. In this study, our group developed an alternative process using irradiation by intense pulsed UV light (IPL) at low temperatures in an air environment. We prepared PHPS-derived SiOx layers using various exposure energies (4.2, 8.4, and 12.6 J cm−2) and then examined their chemical behaviors, compositions, conversion rates, and refractive indices. The resulting SiOx layer exhibited a 100% conversion rate similar to that of a heat-treated silica layer (600 °C) and a refractive index (RI) value identical to that of amorphous SiO2 (1.45). Moreover, the final SiOx thin layer (160 nm ± 0.7 nm) on a polyethylene terephthalate (PET) film had a transmittance of 90.7% and a pencil hardness of 4H at a load of 750 g. The mean hardness and elastic modulus for the SiOx layer were 3.25 GPa, and 27.98 GPa, respectively, values similar to those of SiOx layers formed by roll-to-roll vacuum deposition. Furthermore, the final SiOx thin layer exhibited no cracks after 100 K bending cycles. Overall, we established that the IPL process is effective for converting PHPS into SiOx layers on flexible polymer films that have good hardness, elastic modulus, and transparency. It can be applied in large-scale roll-to-roll manufacturing processes to generate functional materials for the optical film industry. [ABSTRACT FROM AUTHOR]

Composite materials of polyethylene terephthalate with silanized halloysite nanoclay were prepared and characterized. Halloysite was first functionalized with benzoyloxypropyltrimethoxysilane and then incorporated it into the polymer matrix via melt extrusion at 0.5, 1, and 2 wt% clay load ratios. The modified clay was characterized by means of elemental carbon quantification, thermogravimetric analysis, X-ray diffraction, and nitrogen adsorption–desorption. The silanization was confirmed to have taken place with an approximate reaction yield of 5%. While the silanization did not significantly affect the crystal structure or the morphological properties of the clay, a mass loss starting from 190 °C attributed to the organosilane compound used to modify the clay was observed in the reacted samples, along with increased thermal stability. The composite materials exhibited an increase in Young's modulus and a decrease in the ultimate strain, but not a significant change in the oxygen permeability of the composites with respect to the neat PET. [ABSTRACT FROM AUTHOR]

TEMPO (2,2,6,6-tetramethylpiperidine-N-oxyl)-oxidized cellulose nanofibrils (T-CNF) and silver nanowires (Ag NWs) were formulated as active inks. Their rheological properties were investigated to design optimal conditions for processing by the screen-printing process, with the aim of preparing antibacterial patterns. Rheological experiments mimicking the screen-printing process were applied to different ink formulations to investigate their thixotropic and viscosity properties. The experiments conducted at 1wt% total mass content and different ratios of T-CNF/Ag NWs showed that the recovery (%), the recovery time and the viscosity are formulation dependent. A ratio 2:1 (T-CNF/Ag NWs) and total mass content of 2.5wt% were then selected to prepare an ink suitable for screen printing. Printing defects were corrected by addition of water-soluble polymer hydroxypropyl methylcellulose (HPMC). The selected formulation printed on flexible polyethylene terephthalate (PET) substrate displayed a 67.4% antibacterial activity against E. coli in a standard contact active test, with a transparency superior to 70%, proving the promising features of the developed solution for active packaging applications. [ABSTRACT FROM AUTHOR]

Dielectric/metal/dielectric (DMD) transparent electrodes emerged as a compelling alternative to the widely used indium-tin-oxide (ITO) for solar cells and optoelectronic devices. DMD electrodes are especially attractive for flexible substrates, as, in contrast to ITO, they retain their low electrical resistance upon substrate bending and they do not require deposition at elevated temperatures. In a DMD, the choice of the dielectric is mainly dictated by the device architecture. Owing to its high work function, MoO3 is a commonly used hole-selective dielectric layer. The present work investigates MoOx/metal/MoOx (with 2 < x < 3) DMD electrodes, with Ag and Au as metals, fabricated by direct current, magnetron sputtering, at industry-relevant, high deposition rates. This was possible with a properly engineered MoOx target, providing high electrical conductivity and compactness. The sputtered electrodes on polyethylene terephthalate (PET) substrates show higher figure-of-merit than similar, evaporated electrodes in the literature. It is shown that the DMD electrodes with amorphous MoOx layers have low stability in water, but they are stable to other solvents, such as toluene, dimethylsulfoxide (DMSO), dimethylformamide (DMF), chlorobenzene or chloroform, allowing their implementation in devices like organic light-emitting diodes or perovskite solar cells. Further, it is shown that the electrodes show dramatically enhanced mechanical stability compared to ITO, when subjected to tensile bending tests. [ABSTRACT FROM AUTHOR]

Everlasting pursuit of the high energy efficiency as well as meeting fluctuant temperature causes various lighting requirements over the day, which is driving the demand for creating a multifunctional smart window (SW) system. Here, an upper critical solution temperature (UCST)- and/or lower critical solution temperature (LCST)-type SW system (denoted as SWU, SWL and SWU+L, respectively) was fabricated through a simple bio-inspired physical cross-link process between amorphous CaCO3 (ACC) and poly(acrylic acid) (PAA). Series of mineralized hydrogel-based chromic layers were first in situ formed by sealing the composite of ACC in PAA matrix into polyethylene terephthalate (PET) "sandwich structure" to fabricate the SW system. As expected, the SWU system exhibited a typical UCST transition process, bringing about a luminous transmittance (Tlum) of 40.70% at 25 °C and a Tlum of 74.76% at 45 °C. The high scattering of the initial state as well as large optical contrast (ΔTlum = 34.06%) of the SWU system guarantees residential privacy and energy savings. Also, a thermochromic SWL system with a relatively high luminous transmittance (Tlum) of 47.81% at 25 °C and an acceptable solar modulation property (ΔTlum = 16.06%) was constructed. A conceptual SWU+L system was fabricated, that is, a sharp UCST transition followed by a LCST process. This reversible two-stage optical switch process subsequently occurs by continuously increasing temperature, endowing this SW system highly suitable for SW or logic gate. The SW system with multi-thermo-responsiveness brings more flexibility in building facade design. [ABSTRACT FROM AUTHOR]

Linear 1,10-decanediamine was chosen as a modified monomer to prepare modified poly(ethylene terephthalate) (PET) with a low content of amide bonds through two different synthetic methods. To evaluate the effect of amide bonds on the properties of poly(ester amide) analogs (PETAs), the performance of this new type of PET was compared with 1,10-decanediol-modified PET as a control group. The formation of hydrogen bonds in the PETAs was confirmed, and the stability of hydrogen-bonding interactions based on the low content of amide bonds at high temperature was discussed. Interestingly, physical cross-linking networks formed by hydrogen-bonding interactions improved the thermal stability, rheology, and mechanical properties of the PETAs. The crystallization properties were studied in depth by a series of tests, the results of which illustrated that the low content of amide bonds acted as a critical crystallization accelerator in the PETAs. A feasible strategy to prepare high-performance PET, which may be used as a packaging material, was introduced in this work. [ABSTRACT FROM AUTHOR]

Organic conjugated ionic compound 10,10′-dimethyl-9,9′-biacridinum bis(monomethyl terephthalate) (MMT) is doped into graphene oxide (GO) hole-injecting layer to enhance the electroluminescent performance of organic light-emitting diodes (OLEDs). The composite films are characterized in detail by FTIR, SEM, XPS, and UPS. The XPS result indicates the evident π–π stacking interaction between the conjugated structures of GO and MMT. The UPS result shows the decrease in ionization potential of GO due to MMT-doping. As a result, at the optimal doping ratio of 4 wt%, the maximum luminous efficiency of OLEDs is increased to 15.46 cd/A, which is 3.4 times as 4.55 cd/A of the control device. Besides, the luminance is also enhanced to 19950 cd/m2, while the turn-on voltage is decreased to 2.5 V. Doping organic conjugated ionic compound into the GO hole-injecting layer is a facile and efficient approach to improve the electroluminescent performance of OLEDs. [ABSTRACT FROM AUTHOR]

We report the electrothermal properties of AAA trilayer on polyethylene terephthalate substrate which allowed the development of low-cost high-performance transparent thin-film flexible heater (TTFFH) using RF magnetron sputtering. The structural, electrical, and optical properties of the AAA trilayer were investigated at different thickness of the Ag interlayer. The AAA trilayer-based TTFFH yielded saturation temperatures beyond 100 °C at 10 V at optimized Ag interlayer thickness of 5 nm. The time-dependent temperature profile along with its highly stable and reversible thermal behavior was studied. Most importantly, the AAA trilayer-based TTFFH provides a high-performance alternative to the conventional and expensive ITO electrodes at a much lower cost. [ABSTRACT FROM AUTHOR]

In this work, we reported a facile approach to fabricate silver nanowire (AgNW) networks on flexible substrates. Through immersing the modified poly (ethylene terephthalate) with positively charged functional group into the AgNW dispersion with anionic dispersant, a flexible AgNW transparent conductive film was formed by electrostatic adsorption self-assembly process. Even without a post-treatment process, the as-prepared flexible AgNW films exhibited excellent optoelectrical property, low surface roughness and high reliability. It was shown that the insulating dispersant on AgNWs could be effectively removed by an ion bombardment method and then greatly decreased the sheet resistance of AgNW networks. Because of the nature of spontaneous adsorption, this preparation method can be suitable for an arbitrary shaped substrate, which will broaden the application of AgNW conductive films in optoelectronic devices. [ABSTRACT FROM AUTHOR]

Many efforts have been devoted to developing functional poly(ethylene terephthalate) (PET) due to its special biomedical applications in surgical meshes, heart valves, vascular grafts, artificial ligaments, etc. However, for antimicrobial PET the release of antimicrobial component remains a concern. In this work, an antimicrobial compound with terminal epoxy group was synthesized by ethylene glycol diglycidyl ether (EGDE) and polyhexamethylene guanidine hydrochloride (PHMG). Then, EGDE-PHMG was chemically bonded with PET surface through a reaction between the epoxy group of EGDE-PHMG and the amino group of aminated PET to generate non-leaching and permanent antimicrobial PET. The content of PHMG on PET surface, morphology and hydrophilicity of surface, antimicrobial activity and mechanical property of PET were investigated. The amount of EGDE-PHMG on PET surface reached at 3.96 nmol/cm2, resulting in excellent antimicrobial activities against Escherichia coli and Staphylococcus aureus with above 99.99% of inhibition rates. Due to the good hydrophilicity, excellent antimicrobial property, non-leaching characteristic of antimicrobial component and good mechanical properties, the as-prepared antimicrobial PET was promising in the biomedical applications. [ABSTRACT FROM AUTHOR]

A novel smart Janus membrane for unidirectional water transfer and oil-water separation is facilely fabricated by coating graphene nanoplatelets (GNs) onto one side of polyethylene terephthalate (PET) fabric through high-temperature and high-pressure method and subsequently grafting phosphoric acid (HP) into the other side of PET fabric. Results suggest that the prepared HP-PET-GNs Janus membrane with heterogeneous surface wettability attributed to the hierarchical structure of membrane shows special unidirectional water transfer property. The water droplet can penetrate across the membrane from the GNs-coated (hydrophobic) side to the HP-grafted (hydrophilic) side, and be blocked to pass through the membrane from hydrophilic side to hydrophobic side. Moreover, the HP-PET-GNs Janus membrane is found to have the maximum water flux and separation efficiency of 2073 ± 207 Lm−2h−1 and 99.5 ± 0.2% for methylbenzene-water mixture, and the maximum oil flux and separation efficiency of 3113 ± 52 Lm−2h−1 and 99.6 ± 0.1% for carbon tetrachloride-water mixture, respectively. The water separation efficiency and oil separation efficiency could arrive at 99.0 ± 0.1 and 99.3 ± 0.2% even after 10 separation cycles, respectively. It is revealed that the obtained Janus membrane has excellent separation capability for separating the layered oil-water mixtures and possesses wonderful recyclability. [ABSTRACT FROM AUTHOR]

With the development of the human-computer interaction, smart panel requires more of lightweight and transparency. However, most smart panels have been developed based on bulky metal materials and integrated external circuits, which lack flexibility and transparency. Here we demonstrate an ultrathin and flexible tactile sensor based on few-layer graphene films (GFs). The optical transmittance of the sensor is up to 80% in the visible range, which provides optical transparency enough for an aesthetic view. The sensor is assembled through a very simple method consisted a polyethylene terephthalate substrate and two unconnected GFs. The as-assembled sensors can reflect one-dimensional (1D) touch position with a high sensitivity of 0.23 mm−1. The tactile sensor can be used in the monitoring of finger touch, as well as in the detection of liquid temperature. The GFs-based tactile sensor was transferred on the glass substrate to form a smart window, which can warn of a rainy weather coming without sacrificing the window visual functionalities. In addition, a flexible smart panel has been assembled only connect two external circuits and succeed in reappearing the 2D touch path. [ABSTRACT FROM AUTHOR]

Polyethylene terephthalate microfibril-reinforced composites with linear low-density polyethylene (LLDPE) matrix were manufactured by four industrial processing methods: compression moulding, slit-die extrusion with calendering, extrusion blow moulding and injection moulding. The microfibrils were generated in situ by blending the two polymers together and thermomechanically processing the blend. Thin sheets were manufactured in all the processes, except injection moulding, which was employed for making containers. The oxygen permeability of the films was determined using a commercial machine. The greatest improvement in oxygen barrier property (compared to neat LLDPE films), was found in the compression-moulded microfibrillar composite (MFC) films. Two existing theoretical models were modified to reasonably forecast the oxygen permeability of compression-moulded MFC films. The parallel filler model provides a very good fit to the experimental data for the full mass ratio range. The Lewis and Nielsen model was also trialled for various polymer combinations, producing reasonable results with minor modifications. [ABSTRACT FROM AUTHOR]

Highly bendable, transparent, and conductive films composed of silver nanowires (AgNWs) network and polyethylene terephthalate (PET) substrate were prepared by a transfer-printing and second pressing technique using different dimensional AgNWs. The performance of the films as a function of optical and bending performances with low sheet resistance is enhanced, by controlling the diameter and length of AgNWs, area density, and the mechanical press condition. With the optimized mean diameter ( D) ~40 nm and length ( L) ~15 μm, the as-prepared AgNWs-PET film possesses a sheet resistance of 11.5 Ω/sq, transmittance ( T) of 93.4 %, and haze of 1.23 %. The AgNWs-PET film with the second press treatment at 10 MPa for 20 s shows a very excellent bending performance, with less than 8 % change of the sheet resistance after 46,000 bending cycles without any additional conductive polymer. This highly bendable, transparent, and conductive film is suitable for emerging technologies such as flexible display, electrical skins, and bendable solar cells. [ABSTRACT FROM AUTHOR]

The paper examines the roughening along a metal-polymer interface, to find out whether the relevant length scale is on a sub-grain level or on the grain-size level. This is relevant for understanding the possible delamination of a polymer coating on a metallic substrate. Therefore we have investigated the local lattice orientation in heavily strained ferritic steel using electron back-scatter diffraction. From that data we have calculated the components of the local orientation gradient tensor as well as the local Schmid factor for deformation along [100] and [001] on {101} and {112} slip systems. The curvature of the draw-and-redraw steel- polyethylene terephthalate (PET) laminate interface as well as the curvature of the underlying steel lattice was examined in detail. It is concluded that roughening at a sub-grain length scale along the interface is due to plasticity in the interior of the grains. [ABSTRACT FROM AUTHOR]

Among different strategies to reduce costs in microalgae dewatering process via cross-flow filtration, the one related to membrane material was investigated in order to be decreased. Several materials were tested, starting with the ones commonly used in membrane technology [ceramic, polysulfone (PSf) and polyacrylonitrile (PAN)] to the ones generally employed in packaging industry [acrylonitrile butadiene styrene (ABS), glycol-modified polyethylene terephthalate (PETG) and polylactic acid (PLA)], the latter being considerably cheaper. Experiments carried out showed promising results in terms of permeabilities for PSf-Pluronic F127 blended membranes and PAN membranes (11 ± 1 L/h/m/bar and 22 ± 1 L/h/m/bar, respectively, instead of 2 ± 2 L/h/m/bar of PSf membranes), but with high related costs. PLA membranes showed good mechanical properties, biodegradability and price, but low permeability values (5 ± 1 L/h/m/bar). PETG membranes showed attractive results in terms of costs and permeability, but poor mechanical properties. The polymer that offered the best results was the ABS that reached membrane permeabilities of 19 ± 1 L/h/m/bar, maintaining good mechanical properties while filtering the microalgae Phaeodactylum tricornutum Bohlin. Thus, a novel functionality was found for these not so common polymers in microalgae dewatering. This indicates that use of these materials could also be considered in other aqueous micro/ultrafiltration applications. In addition, the biodegradable PLA polymer introduces a new concept of cheap and environmental friendly membrane in this application. [ABSTRACT FROM AUTHOR]

In this study, we attempted to elucidate the Brittle–ductile transition (BDT) behavior of poly(ethylene terephthalate) (PET)/poly(ethylene-octene) (POE) blends under different situations of interfacial compatibility and test temperature. To modulate the compatibility between PET and PEO, maleic anhydride grafted POE (mPOE) was selected as compatibilizer. Three kinds of elastomeric additives, 100 % POE, mPOE/POE (15/85 w/w), and 100 % mPOE, were blended with PET, resulting in three compatibility situations, namely, poor, moderate, and strong interfacial adhesion, respectively. The impact toughness as a function of elastomer content was measured under different interfacial adhesions and test temperature, and microscopic morphology was revealed by scanning electron microscopy and transmission electron microscopy. The results indicated that the interfacial adhesion determines the fashion of microvoiding and even the matrix shear yielding deformation, which will significantly affect the BDT behavior and its response to test temperature. Our study provides not only an effective route to prepare supertoughened PET blends (improved for 20 folds as comparing to the neat PET), but also a fresh insight into the importance of interfacial adhesion on the toughening of thermoplastic/elastomer system. [ABSTRACT FROM AUTHOR]

The aim of this study is to assess the interactions between the constituent phases of poly(ethylene terephthalate) and thereby analyse the validity of a hybrid interaction model in a mean-field micromechanical model based on layered two-phase inclusions. Two different modelling approaches are used to simulate the behaviour of semicrystalline polymers. The first approach is the micromechanical model based on interactions of the crystalline lamellae and the adjacent amorphous layers. The second approach is a two-scale finite-element model of the spherulitic microstructure. Isotropic poly(ethylene terephthalate) is selected as the model material. The deformation mechanisms at the microscopic scale are examined. Various crystal geometries are used in the finite-element model to analyse the case when the crystalline regions do not form an interconnected network. It is shown that the predictions of the microscopic deformation measures obtained with the micromechanical and the finite-element models are similar. Experimental evaluation of the elastic moduli has been performed to further estimate the applicability of the micromechanical model to PET. [ABSTRACT FROM AUTHOR]

Unidirectional flax/polyethylene terephthalate composites are manufactured by filament winding, followed by compression moulding with low and high consolidation pressure, and with variable flax fibre content. The experimental data of volumetric composition and tensile stiffness are analysed with analytical models, and the composite microstructure is assessed by microscopy. The higher consolidation pressure (4.10 vs. 1.67 MPa) leads to composites with a higher maximum attainable fibre volume fraction (0.597 vs. 0.530), which is shown to be well correlated with the compaction behaviour of flax yarn assemblies. A characteristic microstructural feature is observed near the transition stage, the so-called local structural porosity, which is caused by the locally fully compacted fibres. At the transition fibre weight fraction, which determines the best possible combination of high fibre volume fraction and low porosity, the high pressure composites show a higher maximum performance in terms of tensile stiffness (40 vs. 35 GPa). The good agreement with the model calculations (fibre compaction behaviour, and composite volumetric composition and mechanical properties), allows the making of a property diagram showing stiffness of unidirectional flax fibre composites as a function of fibre weight fraction for consolidation pressures in the range 0-10 MPa. [ABSTRACT FROM AUTHOR]

The conductive polymer composite (CPC) based on carbon black (CB), polyethylene (PE), and poly(ethylene terephthalate) (PET) was fabricated, in which the majority of CB particles were selectively localized in the surface of in situ deformed, highly oriented PET microfibrils. The on-line measurement of the electrical resistivity of the CPC materials indicated that the critical time for conductive network formation decreased with the increase of the annealing temperature and the filler loading. The activation energy for conductive network formation was about 96 kJ/mol, which was much higher than that for common CB/PE composite due to the large size of the conductive microfibrils. By a thermodynamic percolation model, the percolation threshold at equilibrium state was 1.735 vol.%, below which the effective conductive network was never formed. The reorganization velocity of the conductive microfibrils was a function of annealing temperature. This study extended insight into the dynamic process of the conductive network formation during annealing. [ABSTRACT FROM AUTHOR]

Polyethylene terephthalate-exfoliated graphene nanocomposites were prepared by injection molding. Nanocomposites with graphene platelets of 2, 5, 10, and 15% weight fractions were molded and tested for mechanical characterization. Transmission electron microscopy imaging along with X-ray diffraction show that the graphene platelets remained intact and were dispersed into the matrix. An exponential increase in the Young's modulus of the nanocomposites was observed, but with current limits on exfoliation they do not yet reach the potential suggested by idealized predictions. [ABSTRACT FROM AUTHOR]

Mixture of starch and amorphous sodium polyborate (SPB) is found to show high flame retardancy, when its aqueous solution is deposited and dried on organic polymer materials such as polyethylene terephthalate (PET) nonwoven, rigid polyurethane (RPU) foam, and polypropylene (PP) nonwoven. The PET nonwoven (10 mm thickness) and the RPU foam (10 mm thickness) coated with the mixture endure the premixed flame of butane gas burner with length of 100 mm for more than 12 min. The PP nonwoven (0.7 mm thickness) endures the nonpremixed flame with length of 65 mm in the 45 degrees Meckel burner test for more than 2 min. The backside temperatures in the both tests remain below 130 °C. The thermal analyses and the SEM observation indicate the mechanism that the SPB foam promotes the carbonization of starch and that the carbonized layer together with the SPB foam insulate inside from oxygen and heat. [ABSTRACT FROM AUTHOR]

Ropes made of twisted polyester (PET) yarns have been replacing traditional steel ropes and chains as mooring lines for offshore platforms in deep-sea environments. In order to optimise rope manufacture and the design of mooring systems, a thorough understanding of the material's mechanical behaviour is necessary. Besides PET, other materials can also be considered such as PEN, as it also a polyester similar to PET but stiffer. This paper presents a study and comparison of PET and PEN fibres' mechanical behaviour, based on experiments carried out on single filaments. Both fibres show similar non-linear tensile behaviour, with an evolution of modulus in four steps. The same microstructural model is proposed for both fibres, based on microfibrils aligned along the fibre axis and composed of an alternation of amorphous, mesamorphous and crystalline phases. The shape of the tensile loading curve is explained by the successive loading of these phases. Creep behaviour is also evaluated by considering the evolution of creep rate with applied load. This evolution is again similar for PET and PEN, both from a qualitative and quantitative point of view. The similarity in creep rate values for both fibres indicates that the microstructural mechanisms involved in creep may differ from those involved in short term tension loading. [ABSTRACT FROM AUTHOR]

Melt blending of polycarbonate (PC)/poly(ethylene terephthalate) (PET) rich in PC at absence/present of different type of tranesterification catalysts was carried out by using reactive extrusion method. The thermal, dynamic, and morphological properties were studied. It was found that all blends are formed by a PC matrix and a semicrystalline (12-20% of crystallinity) of PET dispersed phase. The addition of a catalyst in the mixing process promotes a refined and homogeneous dispersion of PET, as well as it enhances the dynamicmechanical behavior of PC/PET blends compared with PC. These effects are attributed to the emulsifying effect of the PC-PET copolymer generated by transesterification. Additionally, this copolymer contributes to the miscibility between phases as demonstrated by the glass transition ( T) shift of PC phase and PET phase. [ABSTRACT FROM AUTHOR]

A letter about a study on the thermodynamic interaction of the binary components in nanohybrids is presented. The study evaluated the thermodynamic solubility parameters of positron emission tomography (PET) and the functionalized polyhedral oligomeric silsesquioxane (POSS), along with the thermal and mechanical properties of PET/POSS nanohybrids. The physical characteristics of poly(ethylene terephthalate) and POOS nanohybrids is also described.

0.7 mm sheets of blends of polycarbonate (PC) with polyethylene terephthalate (PET) rich in PC in the presence and absence of three different transesterification catalysts have been obtained using reactive extrusion-calendering processing method in order to evaluate the fracture toughness of these materials applying the essential work of fracture (EWF) approach which has not been previously reported in the literature. The morphology has been characterized by scanning electron microscopy (SEM). In addition, the tensile properties of these materials were determined. There is a decrease on the essential term ( we) values of PC/PET blends without transesterification catalysts while blends with transesterification catalysts present an increment in comparison with neat PC which may related to the product of the transesterification that plays like an emulsifier/compatibilizing agent to reduce the interfacial tension between the components of the blend and reduce the interfacial tension between the two immiscible or incompatible component phases to get a better fracture behavior. This is confirmed by the tensile test results obtained which demonstrate higher values for E and σ y in the case of blends with transesterification catalysts compared with neat PC. For non-essential term of fracture (β wp), blends without catalysts exhibit an increase compared with neat PC by increasing the amount of PET which may due to the lowering of the yielding stress. In contrary, the presence of transesterification catalysts and especially Zn-based shows decrease as a consequence of the restriction that occurred on the movement of PC segments during the transesterification reactions or as a decohesion of the dispersed phase during the test. [ABSTRACT FROM AUTHOR]

Nonwovens made of poly(ethylene terephthalate) (PET) and ethylene–vinyl alcohol copolymer (EVOH) are found to become highly fire resistant by treating with amorphous sodium polyborate (SPB). The fire-resistant nonwovens with 10-mm thickness show a gradual temperature increase up to 127 °C and no hole, when their back sides are fired with a gas burner for 12 min. The analysis using the EPMA and the DTA/TG indicates that the SPB foam promotes the formation of char (carbon) layer, and that the char layer together with the SPB foam insulates inside from the oxygen and the heat. [ABSTRACT FROM AUTHOR]

Poly (ethylene terephthalate) films were treated in supercritical CO2 (s-CO2) fluid, and the modifications in tensile properties were investigated. The yield load peaks became ambiguous and the breaking strains and loads decreased for the treated films. However, the tensile modulus and the yield strain were almost unchanged after the treatments. The yield strain is related to the interplay between the amorphous entanglement density and the stability of crystal blocks. WAXD patterns for the films were hardly modified through the treatment. Thus the orientation for the crystal blocks seems to be unchanged. Moreover, laser Raman microprobe spectroscopic analyses revealed that the orientation of molecular chains is almost retained after the treatments. Thus it is natural to assume that the interplay between the amorphous entanglement density and the stability of crystal blocks will also be kept constant even though the swelling of amorphous regions with s-CO2 occurs during the treatments. From differential scanning calorimetry measurements, it was found that the heat of fusion for the crystallites was a little increased without shifting the peak position after the treatment. Therefore, the increase in crystallinity is not due to the thickening or crystal perfecting for primary lamellae, but due to the secondary crystallization. The increase in crystallinity caused by the secondary lamellae crystallized and combined onto the primary lamellae seems to have reduced the amorphous chains to be deformed easily at tensile tests. Then the breaking strains and loads decreased for the treated films. [ABSTRACT FROM AUTHOR]

Micro- or nano-fibrillar composites (MFCs or NFCs) are created by blending two homopolymers (virgin or recycled) with different melting temperatures such as polyethylene (PE) and poly(ethylene terephthalate) (PET), and processing the blend under certain thermo-mechanical conditions to create in situ fibrils of the polymer that has the higher-melting temperature. These resulting fibrillar composites have been reported to possess excellent mechanical properties and can have wide ranging applications with suitable processing under controlled conditions. However, the properties and applications very much depend on the morphology of created polymer fibrils and their thermal stability. The present paper develops an understanding of the mechanism of micro-/nano-fibril formation in PE/PET and polypropylene (PP)/PET blends by studying their morphology at various stages of extrusion and drawing. It is revealed that this subsequent mechanical processing stretches the polymer chains and creates fibrils of very high aspect ratios, thus resulting in superior mechanical performance of the composites compared to the raw blends. The study also identifies the primary mechanical properties of the main types of MFCs, as well as quantifying their enhanced resistance to oxygen permeability. Furthermore, the failure phenomena of these composites are studied via application of the modified Tsai–Hill criterion. In addition to their usage as input materials in different manufacturing processes, possible applications of these fibrillar composites in two different areas are also discussed, namely food packaging with controlled oxygen barrier properties and biomedical tissue scaffolding. Results indicate a significant scope for using these materials in both areas. [ABSTRACT FROM AUTHOR]

Thermal and spectral analysis is conducted routinely to characterise a large range of materials and compounds. However, tests are often conducted independently on separate samples where comparison between essentially the same material can provide conflicting results. Simultaneous thermal and spectral measurements have the advantage of being able to directly compare results using the same sample. A novel design of a simultaneous thermal and spectral technique is described along with application examples that highlight the benefits of this technique. The thermal analysis was conducted using Differential Scanning Calorimetry (DSC) and the in situ spectral analysis was conducted using a Fourier Transform Near Infrared (FT-NIR) spectrometer. Two examples are used to illustrate the versatility and potential advantages of the combined thermal and spectral method. Analysis of the first and second order transitions of polyethylene terephthalate (PET) is presented along with the pharmaceutical polymorphic conversion of carbamazepine from Form III to Form I through an isothermal hold at 160 °C. [ABSTRACT FROM AUTHOR]

This study addresses the three-dimensional structure and mechanical properties of perpendicular-laid nonwovens produced from PET and PET/PE bicomponent fibers. Two different web-forming methods, air folding and mechanical folding systems, have been employed to produce the perpendicular-laid nonwovens. It is proved that both systems can produce well-developed perpendicular-laid structures. A comparison has been made between mechanical properties and fiber orientation distribution function (ODF). ODFs at three faces of nonwovens were analyzed by image analysis techniques using the two-dimensional Fast Fourier Transform (2D FFT). Further, mechanical measurements were performed at various azimuthal directions to investigate the related mechanical responses in three-dimensions. [ABSTRACT FROM AUTHOR]

Recycled PET from bottles was processed from flakes, which containing different amounts of water uptake. After this process, they are subjected to characterization by differential scanning calorimetry (DSC), thermogravimetry (TG), and Fourier-transform infrared spectroscopy with an attenuated total reflectance accessory (FTIR-ATR). From the DSC and TG results it can be postulate an increase in the proportion of short-molecular-weight distribution in the PET chains, due to the hydrolytic degradation of recycled PET during the thermopressing in presence of water. This hydrolytic degradation probably formed more polar groups on the surface of the processed and recycled PET, like carboxyl groups, as observed by FTIR-ATR. [ABSTRACT FROM AUTHOR]

The recent discovery of melt-processable poly(tetrafluoroethylene) (PTFE) allows for common thermoplastic-polymer processing technologies to be applied to this unique polymer, which heretofore was considered to be highly intractable. In this paper, we report simple melt-spinning of monofilaments of a set of melt-processable (modified) PTFE grades with weight-average molar masses ( M w) ranging from 77 to 292 kg/mol. Fibers were spun at 380 °C at draw-down ratios of up to 2,750, yielding filaments of linear densities as low as 0.8 tex, corresponding to a diameter of ∼20 μm. The maximum Young’s modulus and tensile strength of as-spun fibers produced in this study were 91.7 cN/tex (1,972 MPa) and 12.0 cN/tex (258 MPa), respectively, accompanied by a strain to break of 24%. [ABSTRACT FROM AUTHOR]

In this study two Poly (Ethylene Terephthalate) (PET) polymers obtained from mineral water bottles and a virgin fiber grade PET polymer were investigated. In order to improve their properties when reprocessed at high temperatures, recycled polymers were blended with virgin one. Thermal and rheological properties of extruded recycled/virgin (PET-V/R) blends showed a good microstructural stability compared to extruded pure recycled polymers. Mechanical behaviour of melt spun fibers obtained from recycled/virgin blends were investigated in static (tensile) and dynamic (DMA) modes and gave interesting properties. Fatigue failure of fibers was also studied and resulting fracture morphologies were analysed by Scanning Electron microscopy (SEM). [ABSTRACT FROM AUTHOR]

In this paper, poly(ethylene terephthalate) (PET) spunbonded fibers with tensile strength of 9.67 cN/dtex and diameter of 7 μm were produced in Nordson’s MicroFil™ Spunbond System with a positive attenuator pressure. The influences of the slot width of the attenuator on the properties of PET spunbonded fibers were studied, and Fourier transformation infrared spectrophotometry (FT-IR) and Wide-angle X-ray diffraction were applied to characterize the crystalline and orientation structure of PET spunbonded fibers as well. It was found the attenuator with positive air pressure is more advantageous to spin PET spunbonded fiber and the fiber becomes finer and its’ tensile strength becomes higher with the decrease of the slot width. The air speed in the attenuator was predicted as well. [ABSTRACT FROM AUTHOR]

The effect of the bonding force during flip chip-on-flex (FCOF) assembly on the electrical performance of the nonconductive adhesive (NCA) interconnects was investigated in this study, under the precondition of a reduced processing temperature in order to minimize thermally-induced damage to the low-cost flexible substrates. Pressure cooker tests (PCT) were performed to assess the reliability performance of the adhesive joints in high temperature and high humidity conditions. The assembly process was modified and the processing temperature and the bonding force were adjusted according to the experimental results to enable the use of low cost substrates, such as poly(ethylene terephthalate) (PET) materials in smart card fabrication. [ABSTRACT FROM AUTHOR]