Macromolecular Research最新文献

Temporary protective film (TPF) is used as a surface protection for the encapsulation layer during cell cutting and laser lift-off in the manufacturing process of an organic light-emitting diode. TPFs should satisfy the following requirements: good wettability on the surface during the protection step, low peel strength, and clear debonding properties during the removal step. Herein, we used multi-arm-structured trimethylolpropane ethoxylate (TPEG) and linear-structured poly(ethylene glycol) 200 (PEG200) plasticizers to attain these requirements for a polyurethane-based a pressure-sensitive adhesive (PSA). The PSA films with TPEG successfully satisfied the aforementioned requirements. The PSA films with plasticizers exhibited similar wettability and polar surface energy with those of the substrate, thereby demonstrating an interface energy with the substrate of approximately zero. Additionally, the 180° peel strength test showed that the peel strength of the PSA with TPEG was lower than that with PEG200. The observation coincides with small-amplitude oscillatory shear test results obtained via rotational rheology measurements. Furthermore, debonding properties were characterized using time-of-flight secondary ion mass spectrometry (TOF–SIMS) of the adherend surfaces after peeling off the TPFs. The structural properties of TPEG affected migration to a lesser extent than those of PEG200. This is in good agreement with the surface free energies of the adherend surfaces after removing the TPFs. The proposed design strategy can be applied in electronic industry where surface protection using ultra-peelable adhesive films is required.

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This study aimed to address the environmental concerns associated with petrochemical-derived bisphenol-A, commonly used in epoxy resin synthesis, by developing an eco-friendly alternative utilizing bio-based ascorbic acid, or vitamin C. The epoxy compound was synthesized by leveraging the hydroxyl group inherent in ascorbic acid through a reaction with epichlorohydrin. Optimal curing conditions were determined via dynamic scan and isotherm analysis using Differential Scanning Calorimetry (DSC) for the newly synthesized epoxy resin in combination with isophorone diamine (IPDA) as the curing agent. The cured product, obtained under the identified optimal curing conditions, exhibited a soft hardened form with a tensile strength of 7.5 MPa and an elongation of 6%. These findings underscore the feasibility of synthesizing a commercially viable eco-friendly epoxy resin utilizing ascorbic acid, thus contributing to the ongoing pursuit of sustainable material alternatives. The results suggest potential scalability for mass production, emphasizing the significance of this approach in addressing the demand for environmentally friendly materials in various industrial applications.

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Synthesis of ascorbic acid-based epoxy resin.

In this project, the oxidative chemical polymerization method is used to prepare polymer composite that consisting of polypyrrole polymer (PPy) and iron oxide nanoparticles (Fe₂O₃NPs). Then deposited this blend (PPy/Fe₂O₃) onto the PET substrate to creating flexible nanocomposite PET/(PPy/Fe₂O₃). Analyzing the samples using X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) proves that the composite was effectively formed. With varying Fe₂O₃ ratios, the dielectric parameters of PET polymer and PET/(PPy/Fe₂O₃) composite have been documented at frequencies of 40–5.6 MHz. The surface properties were significantly enhanced by irradiation. The surface free energy increases from 41.36 mJ/m² to 66.23 mJ/m² and water contact angle reduces from 58.36° for PET to 39.25°. The results demonstrated that the composite surface characteristics were enhanced as the concentration of Fe₂O₃ changed. The obtained data showed that the fabricated samples have better properties than the PET films that can be utilized in many applications as capacitors and storage devices.

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a SEM of PET, b SEM of PPy/Fe₂O₃, c SEM of PET/(PPy/Fe₂O₃, d contact angle with ratiosof Fe₂O₃ and e surface free energy with ratios of Fe₂O₃

The purpose of this study is to identify factors affecting the dispersion and printing properties of pastes that are required to form fine line width electrodes by controlling the rheological properties of pastes applied in various fields. In particular, to solve the problem of high cost and low efficiency of silver used in the front electrode of silicon solar cells, it is necessary to print uniform fine lines with high aspect ratio to achieve higher efficiency while reducing raw material consumption. In this study, ethyl cellulose (EC), a conventional general-purpose binder, and xanthan gum (XG), which is widely used as a thickener in the food industry and has excellent temperature stability and the advantage of having a high viscosity even with a small content, used as binders. An organic solution was prepared by completely dissolving the binder in a solvent, and then inorganic particles and glass flecks were added to prepare the final paste. The rheological properties of the paste were measured, and the aspect ratio and the electrical conductivity of the electrodes were assessed after screen printing and firing. The results indicated that the paste prepared with XG binder exhibited a higher overall viscosity compared to the paste with EC binder and demonstrated a superior shear-thinning behavior. The pastes with optimal printing properties were found to contain 12 wt% EC and 7 wt% XG, respectively. In the frequency sweep test, XG had higher G' and G'' than EC, showing relatively good sedimentation stability and high aspect ratio. Viscosity recovery through hysteresis test was also better for XG than EC. For the final electrical conductivity, both EC and XG showed a value of 10³ Ω⋅m order. However, if the electrodes were formed from a paste made of XG, the final solar cell efficiency is expected to be higher due to the larger area receiving sunlight due to the high aspect ratio.

Graphical Abstract

This study investigates the rheological properties of pastes formulated with ethyl cellulose and xanthan gum for screen-printed electrodes in silicon solar cell fabrication. Xanthan gum-based pastes exhibit higher viscosity and better shear thinning behavior compared to ethyl cellulose-based pastes, with optimal printing properties observed at 7 wt% xanthan gum content. The findings suggest that utilizing xanthan gum-based pastes could lead to higher efficiency in silicon solar cells due to the potential for achieving larger aspect ratio electrodes

The utilization of bio-derived zinc metal–organic frameworks (bioZnMOFs) as crystalline materials represents an advanced innovation with dual significance in both physicochemical and biological realms. BioZnMOFs based on essential amino acids such as l-phenylalanine, l-histidine, and l-tryptophan were dispersed in collagen–starch hydrogels (mass ratio 1%) to generate the materials ZnF, ZnH, and ZnT, respectively. Using solid-state ¹³C NMR, the chemical components of these systems were identified. The surface structure of these biomatrices was inspected by SEM, indicating that ZnT generates the largest occluded clusters. EDS analysis revealed that Zn(II) ions are uniformly distributed in all the semi-IPN biomatrices. WAXS analysis demonstrated a semi-crystalline structure, while FTIR analysis revealed that the ZnH matrix shows the greatest physicochemical interaction processes, benefiting crosslinking (40 ± 5%), swelling (4900 ± 510%), storage modulus (1000 Pa at 35 Hz), and reduced gelation time (10 ± 1 min) in this biomatrix. These materials display slow degradation in collagenase-rich environments and vegetable substrate. ZnH and ZnT matrices stimulate monocyte metabolism, while ZnF and ZnH actively promote fibroblast metabolism, encouraging proliferation at 48 h. ZnT shows modulation of IL-10 and TNF-α cytokine secretion in monocytes, suggesting its potential in wound healing applications. Additionally, the ZnT matrix enhances tomato root cell metabolism and proliferation. After 30 days, plants growing on ZnT matrices exhibit larger stem diameters and more leaves, showcasing their agricultural potential. Overall, these bioZnMOF-based materials offer versatile solutions with promising applications in biomedicine and agriculture.

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High energy radiation processing has proven to be remarkably effective in enhancing the properties of polymeric materials. Specially, electron beam (E-beam) radiation stands out as a versatile technique for crosslinking, compatibilizing, and grafting polymer blends and composites. Its reputation for simplicity, high speed, environmental friendliness, and user-friendliness has made it the preferred method in industries such as automotive, electrical insulation, ink curing, surface modification, food packaging, medical sterilization, and healthcare. This review focuses on recent advancements in the application of E-beam irradiation to ethylene vinyl acetate (EVA) blends and composites, with a specific focus on incorporating partially nanoscale clay to achieve desired properties and the controlled crosslinking of blends and nanocomposites using high-energy radiation. Numerous studies have investigated the development and modification of EVA with various thermoplastic and elastomeric polymers, highlighting radiation-induced grafting of different monomers onto the polymer backbone. The review primarily examines the utilization of EVA blends and composites for the purpose of adjusting their physical, chemical, thermal, surface, and structural properties. Additionally, it investigates the formation of crosslinking by analyzing gel content and optimizing the dosage of crosslinking co-agents and fillers. Furthermore, the study explores the effect of E-beam irradiation on the tensile properties, specifically the enhancement of tensile strength resulting from crosslinking formation at varying E-beam radiation doses. Additionally, the diverse applications of high-energy radiation-modified polymers in industries such as automotive, wire and cable insulation, heat shrinkable tubes, sterilization, biomedical, nuclear, and space industries are discussed. These applications demonstrate the extensive potential and practicality of utilizing high-energy radiation processing to enhance the properties of polymeric materials in various industrial settings.

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Effects of electron beam irradiation on ethylene vinyl acetate blends and composites.