Resin Film Research Articles

Research Progress on the Preparation of Composite Materials by Resin Film Infusion (RFI)

The resin film infusion (RFI) process is a novel composite molding method for high-fiber content, excellent mechanical properties, low porosity, and adjustable thickness. This review examines two common resin materials used in the RFI process: bismaleimide resin (BMI) and epoxy resin. Furthermore, numerical simulation methods for isothermal and non-isothermal processes in the RFI process are described, focusing on the analysis of the mathematical model of resin flow. Finally, it covers the unique properties of RFI composites and showcases the RFI process’s cost-effectiveness and functionality in fabricating composite structures for various applications. The limitations and potential future developments of RFI process molding technology are also summarized.

Investigation on para‐aramid fiber‐reinforced poly‐ether ketone‐ketone high‐performance composite for ballistic application

AbstractThis investigation highlights the performance of high‐performance polymeric composite for ballistic application. Therefore, reinforcement of para‐aramid fiber in poly‐ether‐ketone‐ketone (PEKK) resin film has been made. The surface of PEKK and para‐aramid fiber was modified by low‐pressure plasma to enhance the surface energy of the polymeric film and reinforcement fiber. The polymeric composite was manufactured by compression molding with a pressure of 2 bar, temperature of 310°C with holding time of 15 min. Due to low‐pressure plasma treatment of PEKK film and para‐aramid fiber, the tensile strength of the composites increases considerably. In the accelerated aging test, the tensile specimens are dipped into concentrated HNO3 and NaOH medium for 15 days. It is observed that there is a decrease in tensile strength. The ultimate tensile strength (UTS) of the virgin specimen was compared to the environmentally aged for 15 days and in this case, also there was a decrease in tensile strength. Two types of composite panels were made (i) 25 layers of PEKK film with 24 layers of para‐aramid fabric and (ii) 45 layers of PEKK film with 44 layers of para‐aramid fabric with 15 mm × 15 mm. The composite panel was tested with four 9 mm handgun bullets fired from a distance of 5 meters with a speed of 430 m/s. In the case of 25 layers of PEKK film with 24 layers of para‐aramid fabric, the composite failed under ballistic test, however, in the case of 45 layers of PEKK film with 44 layers of para‐aramid fabric, the composite was successful under ballistic test.Highlights Film stacking method of PEKK and Aramid fiber. Ballistic composite panel with layers of PEKK and Aramid fiber. Enhancement of mechanical properties of the composite panel with plasma surface treatment. Ballistic testing of composite panel.

Does the universal adhesive's film thickness affect dentin-bonding effectiveness?

To investigate the influence of adhesive resin application modalities on the film thickness of the adhesive resin and the effectiveness of a two-step universal adhesive (UA) bonded in self-etch (SE) bonding mode to high C-factor class-I cavity-bottom dentin. After application of the primer of G2-Bond Universal (G2B, GC), the adhesive resin was applied into standard class-I cavities (human molars) following four application modalities: (1) one layer, strongly air-blown; (2) one layer, gently air-blown; (3) two layers, each gently air-blown; (4) one layer, not air-blown. After being restored with composite, each tooth was sectioned to obtain one micro-specimen (n = 10), of which the adhesive resin film thickness was measured using optical microscopy. The micro-tensile bond strength (μTBS) was tested immediately or upon 100,000 thermocycles. Statistical analyses involved Kruskal-Wallis and Mann-Whitney U testing (p < 0.05). G2B's μTBS was significantly affected by the adhesive resin application modality and aging. Gently air-blowing the adhesive resin resulted in significantly higher immediate μTBS than strong air-blowing or no air-blowing. No significant difference in μTBS was found between single or double gently air-blown adhesive resin applications. The adhesive resin film thickness significantly varied with the application modalities. A too thin or too thick adhesive resin film thickness adversely affected bond strength of the two-step UA applied in SE mode and high C-factor condition. The adhesive resin layer thickness can affect the bonding performance of two-step UAs in high C-factor cavities. Dental clinicians remain advised to avoid improper air-blowing of UAs and strictly follow the application instructions.

Recyclable polytriazole resins with high performance based on Diels-Alder dynamic covalent crosslinking

Abstract N,N-Di-2-propyn-1-yl-2-furanmethanamine (DPFA) was synthesized from 2-furanemethylamine and 3-chloropropyne. Then, furan-containing polytriazoles were made from DPFA and diazide compounds. The Diels-Alder (DA) reaction between 4,4′-bismaleimidodiphenylmethane and furan-containing polytriazoles was used to prepare recyclable polytriazole resins. The effects of the main chain structures on the reversible processes and mechanical properties of the resins were investigated. The results show that the flexibility of the chain structures could be regulated by introducing different contents of azide-terminated polyethylene glycol (PEG) in the polymerization process. The PEG segments could not only promote the degree of the DA reaction but also play a role in reinforcing and/or toughening the recyclable polytriazole resins. RFPTA-5 resin film displays a tensile strength of 107.2 MPa and RFPTA-20 resin film shows an elongation at break of 224.8%. Moreover, the resin films demonstrate high recyclability.

BaSO4-Epoxy Resin Composite Film for Efficient Daytime Radiative Cooling.

Conventional cooling methods are based on active cooling technology by air conditioning, which consumes a large amount of energy and emits greenhouse gases. Radiative cooling is a novel promising passive cooling technology that uses external space as the cooling source and requires no additional energy consumption. Herein, we propose an approach to prepare highly dispersed BaSO4 nanoparticles (NPs) using a direct precipitation method combined with the in situ surface modification technology. The as-prepared PVP-modified BaSO4 NPs with an average size of 20 nm can be stably dispersed in ethanol for more than 6 months and then were used as building blocks to prepare spherical BaSO4 clusters with an average size of 0.9 μm using a scalable spray drying technique. The BaSO4 NPs/clusters (mass ratio 1:1) were used for preparing radiative cooling epoxy resin film, showing a high solar reflectance of 71% and a high sky window emissivity of 0.94. More importantly, this composite film displays superior radiative cooling performance, which can reduce the ambient temperature by 13.5 °C for the indoor test and 7 °C for the outdoor test. Compared with the commercial BaSO4 filled film, our BaSO4-epoxy resin composite film offers advantages not only in radiative cooling but also in mechanical properties with a 16.6% increase of tensile strength and 40.1% increase of elongation at break, demonstrating its great application potential in the field of building air conditioning.

Control the structure of the polyacrylate/epoxy resin film through photopolymerisation

ABSTRACT Double-layered polymer-stabilised cholesteric liquid crystal (PSCLC) films constructed from epoxy resin and polyacrylate were prepared based on photopolymerisation-induced phase separation. Moreover, a PSCLC film with an interpenetrating network was prepared through a one-step photopolymerisation approach. A colourful pattern was prepared based on these two approaches, which was suitably applied for decoration.

Deformation Mechanisms and surface/interface Characteristics of Titanium-based Thermoplastic FMLs under Ultrasonic Impact Loading

Some typical defects like delamination, fiber fracture, non-uniform resin distribution and springback are inevitable as titanium-based thermoplastic FMLs are formed by general stamping process at elevated temperature due to the significant differences of various constituent materials in mechanical and thermal properties as well as deformation mechanism. Thus, a novel ultrasonic impact sizing/shaping process method was proposed in the present work, in which a stepped horn and impact tools with a cylindrical tip end was designed by means of vibration modal and harmonic response analysis, and the corresponding experiment setup was established to verify the process mentioned above. Moreover, ultrasonic impact tests were carried out for titanium-based FMLs stacked by titanium sheet, thermoplastic resin film and carbon fiber reinforced fabric to reveal their sizing/shaping mechanism and the effect of key process parameters such as ultrasonic amplitude, scanning speed of impact tool and its tip end diameter on the surface and interface characteristics of titanium-based FMLs. The research results show that the ultrasonic impact scheme with the ultrasonic amplitude of 12 μm, the scanning speed of impact tool within 2 mm/s ∼ 3 mm/s, the tip end diameter of impact tool within Ø4mm∼Ø6mm are proper for the ultrasonic impact sizing/shaping process of titanium-based FMLs.

Enhanced holding ability between resin and silanization modified diamonds through sintering Si[sbnd]N bond formation at low temperature

Resin-bonded diamond tools often suffer from poor durability and short lifespan due to the agglomeration of abrasive diamonds and the poor holding ability between diamonds and resin, resulting in diamond detachment during the working process. Modifying the diamond surface is necessary to improve the dispersion of diamonds and the holding ability between diamond and resin. However, common metallic modification methods can cause fine-grained diamonds (FGDs) to agglomerate, and metal plating cannot form a chemical bond with resin at low temperatures for preparing resin-bonded diamond tools. A practical non-metallic method for modifying diamond surfaces was proposed to address these issues, utilizing a silane coupling agent to enhance the binding forces between diamonds and binding agents. A uniform amorphous SiO2 film, with a thickness of 30–40 nm, was developed on FGDs with the hydrolysis and condensation reactions of tetraethylorthosilicate in a water and alcohol mixed solution. The SiO2 layer formed with the CO, CO, and C-O-Si chemical bonds can increase electrostatic repulsion between diamonds, overcoming diamond agglomeration. FGDs modified with SiO2 were combined with phenolic resin and pressed at 170 °C, forming SiN bonds between the resin and SiO2 film and improving the bonding force. Moreover, the SiN bonds can be produced at low temperatures, reducing the risk of diamond detachment during their operation. Hence, the lifespan of modified diamond wheel increase by 22 % than that of pristine diamond wheel. This study provides valuable guidance for developing high-performance, long-lasting, resin-bonded diamond tools.

Preparation and characterization of lignin-based epoxy resin via one-step grafting of lignin with E-44 epoxy resin

Aiming for high-value utilization of lignin in pulping black liquor, lignin-based epoxy resin (RLEP) was synthesized by one-step grafting of refined lignin (RL) with E-44 epoxy resin, and then the lignin-based epoxy resin film (RLEPF) was prepared by using phenolic amine as the curing agent. The results showed that the lignin ethers were synthesized by copolymerizing the hydroxyl groups of lignin and the epoxy groups of E-44. Upon increasing the lignin dosage, the epoxy value of RLEP decreased, and the fracture surface of RLEPF changed from a clear-layered structure to an uneven rough surface. Furthermore, the increased lignin dosage resulted in enhancing the elongation at break of RLEPF while the tensile strength and thermal stability were decreased. Compared with the pure E-44 epoxy resin film, the elongation at break of the RLEPF-25 sample significantly improved from 10.61% to 136.51%. Therefore, the lignin-based epoxy resin film prepared by grafting refined lignin with E-44 exhibited excellent toughness. This novel study thus highlights pathways for the resource utilization of the pulping black liquor lignin.

Healing study of poly (ether-imide) and poly ether ether ketone using resin films and a parallel plate rheometer

Healing study of poly (ether-imide) and poly ether ether ketone using resin films and a parallel plate rheometer

Laser–induced breakdown spectroscopy combined with surface coating to enhance emission line intensity of metallic elements in metal sheet

Emission intensity plays an important role in laser–induced breakdown spectroscopy. A new sample preparation method is proposed to enhance the emission intensity for determining metallic elements. A layer of epoxy resin film is cured on the surface of a metal sheet sample, and a laser beam is used to ablate the film and form a circular hole through it. Results show that by using the proposed method, the emission intensity for Al, Cr, Cu, Fe and W increases by 66.7%–699.6%, and the relative standard deviation (RSD) decreases from 6.5%–25.5% to 0.2%–12.9%. This suggests that emission lines with high intensity and low RSD can be obtained using the proposed method. This convenient and low–cost method has the potential for improving the quantification and imaging performance of bulk samples.

Evaluation and Improvement of Bio-Based Sustainable Resin Derived from Formic-Acid-Modified Epoxidized Soybean Oil for Packaging Applications.

Bio-based epoxy resin materials have obtained significant attention in the packaging industry due to concerns about the environmental and economic impacts of traditional petroleum-based plastics. The aim of this research is to improve bio-based resins' properties by investigating varying formic acid contents in the presence of a green catalyst and characterizing their physical, chemical, and mechanical properties for further scaled-up bio-based resin production for industrial packaging applications. The crude soybean oil was epoxidized with formic acid as an oxidizing agent at varying equivalent weights of 10:1 to 10:10 of soybean oil: formic acid in the presence of hydrogen peroxide and choline chloride-oxalic acid as a bi-functional green catalyst. The effect of increasing the amount of formic acid used to epoxidize crude soybean oil was evaluated with infrared (IR) spectroscopy, rheological, and epoxy yield measurements. The results demonstrated that formic acid significantly influenced the epoxidation of soybean oil, leading to a higher conversion of carbon-carbon double bonds, with a selectivity of 98% when the ratio of soybean oil to formic acid was between 10:5 and 10:10. The bio-resin film was formulated using the improved epoxidized soybean oils-from ESO (10:2.5) to ESO (10:10)-and equal amounts of acrylic acid. The results showed that resin films led to an improvement in tensile strength (ca. 180 MPa) and thermal stability at 360 °C. Although further research is necessary, this study provides valuable insights for designing an effective epoxidation process for renewable sources and developing bio-resin materials for future packaging applications.

Superior high-temperature mechanical and thermal performance of carbon fiber/epoxy composites by incorporating highly dispersed aramid nanofibers

Enhancing the high-temperature properties of polymer-matrix fiber-reinforced composites is a challenging task, given the thermal limitations of polymer resins. In this study, we propose a straightforward and efficient method for producing high-performance carbon fiber/epoxy composites with superior high-temperature properties by incorporating highly dispersed aramid nanofibers. To achieve high dispersion of aramid nanofibers in the epoxy, we used a sequential solvent exchange method, which allowed us to fabricate B-stage cured resin films. The aramid nanofiber-hybridized carbon fiber composite, manufactured using resin film infiltration, demonstrated impressive mechanical and thermal properties. Specifically, in the glass transition temperature range at high temperatures, the composite provided 3.1, 5.1, and 6.8 times higher Young's modulus, tensile strength, and short beam strength, respectively, compared to the unmodified composite. Moreover, incorporating aramid nanofibers significantly increased the glass transition temperature by 31 °C, resulting in 2.4 times higher storage modulus and improved thermal stability with an increase in the total weight residue at 800 °C by 33.7 %. Therefore, the highly dispersed aramid nanofiber-embedded carbon fiber composite shows great potential for use in high-performance polymer composite applications.

Interfacial Behavior Between Mold Resin and Sputtered Film Deposited on Electromagnetic Shield Packages

Interfacial Behavior Between Mold Resin and Sputtered Film Deposited on Electromagnetic Shield Packages

Study on corrosion law and characteristics of composite modified basalt fiber concrete in acid environment

The deterioration of concrete materials in the sewage environment is prominent, significantly shortening the structure's service life. Based on the composite modification method, modified basalt fiber high-durability concrete is proposed to solve the problem of insufficient material durability in the sewage environment. The acid environment erosion test was carried out for the modified concrete materials. The macroscopic performance indexes were obtained, such as apparent corrosion characteristics, water absorption rate and compressive strength. The corrosion mechanism and deterioration law of concrete materials under an acid environment were revealed by combining the analysis of the fine structure and corrosion product composition. The results show that the hydration reaction of the modified concrete was adequate. The generation of C–S–H gel and Ca(OH)2 increased significantly. The porosity was reduced by 40%, and the initial strength was increased by 12%. After 240d corrosion, the strength of ordinary concrete was degraded by 41%. The degradation rate of modified concrete was 26%, its residual strength was 1.4 times that of ordinary concrete, and its corrosion-resistant ability was greatly improved. Based on the experiment, the corrosion resistance mechanism analysis was carried out, and it was found that the inorganic aluminium salt compound salt crystal expansion modification effect is better than the sodium methyl silicate reticulated resin film modification. However, after double doping, the corrosion resistance is reduced instead, and it is recommended that inorganic aluminium salts be preferred as anti-corrosion and anti-seepage adding materials. The research results of this paper can better enhance the acid environment erosion resistance of concrete, engineering application prospect is good.

Unveil self-plasticized polyvinyl alcohol derived customizable patterned photosensitive resin films

Since the invention of movable type in ancient times, relief printing, often called flexographic printing, has been performed to mass-produce artifacts ranging from decorative graphics to printed media. Polyvinyl alcohol (PVA) substrates are soluble in water with low toxicity but have the disadvantages of poor elasticity and brittleness. Thus, this study aims to improve the resilience of water-developable photopolymer resin plates by modifying PVA with allyl polyoxyethylene ether (APEG) in solution polymerization. In order to better control polymerization, the reactivity ratios of both were investigated (rVAC = 0.32 and rAPEG = 0.12). Impressively, the lowest glass transition temperature (Tg) of the modified PVA (m-PVA) can reach −49.98 °C, which is significantly lower than that of PVA0599 (degree of polymerization = 500, degree of hydrolysis = 99 mol%) (Tg = 52.02 °C). Moreover, this resultant m-PVA exhibits superior elongation at break (443.23 ± 37.65 %) than PVA0599 (9.98 ± 3.95 %). It is found that photopolymer plates of m-PVA have maintained a 98 % elasticity recovery rate even after water washing. Due to the better elasticity of m-PVA, the clarity of the photopolymer plate is higher than that of traditional PVA. This water-soluble self-plasticized m-PVA is expected to be applied to the fine flexographic printing industry, such as electronic devices, components, and sensors.

Thermal management mechanism employing transparent nanostructures for winter and summer seasons for indoor environments

Metamaterials aim to recognize and emphasize their impact on multiple applications, and the objective of this study is to achieve higher performance of metamaterial solar absorbers for thermal management during winter and summer seasons. This paper outlines the metamaterial design strategy using low-cost materials, with its essence being the exploitation of the unique properties of the metamaterial to extend the composite performance of transparent planar solar absorbers. We designed a transparent multilayer planar absorber coating by using Iron Sesquioxide (Fe2O3) as the dielectric spacer and Titanium (Ti) metal for ground and resonator metal layers with both the cladding made of Silicon dioxide (SiO2) within thin resin film. The proposed MIM design affirms the presence of the negative refraction property of light, a unique property for metamaterials, Additionally, it can be used to retain sufficient energy during absorption which will enhance winter thermal management in buildings for angles of incident θ < 50° and the same setup accessed at θ > 50° will highly reflect the energy and will maintain the low temperatures in a given room during the summer season.

Wavelength-dependence of Norrish type I cleavage reactions in carbonyl groups of dammar resin triterpenoids and its implications for accelerated aging of organic materials

Norrish Type I cleavage reactions of carbonyl groups in dammar triterpenoids were studied using different wavelengths of UV exposure. Films of dammar resin were exposed to xenon arc irradiance, using longpass filters with varying cut-on wavelengths. The results were studied using gas chromatography mass spectrometry of the triterpenoid fraction. It was shown that α-cleavage of carbonyl groups, leading to formation of A-seco compounds, takes place at wavelengths present in daylight filtered by window glass, thus validating the aging method for the study of the stability of materials during indoor exposure. Claims that xenon arc exposure leads to abnormal degradation appear incorrect. By eliminating UV radiation entirely below 400 nm, Norrish reactions are inhibited. These results are of particular relevance in accelerated aging studies in heritage science but also in other fields.

Elastohydrodynamic lubrication of soft-layered rollers and tensioned webs in roll-to-plate nanoimprinting

This work presents the development of a numerical model for the elastohydrodynamic lubrication of roll-to-plate nanoimprinting with flexible stamps. Roll-to-plate nanoimprinting is a manufacturing method to replicate micro- and nanotextures on large-area substrates with ultraviolet-curable resins. The roller is equipped with a relatively soft elastomeric layer, which elastically deforms during the imprint process. The elastic deformation is described by linear elasticity theory. It is coupled to the pressure build-up in the liquid resin film, which is described by lubrication theory. The flexible stamp, which is treated as a tensioned web, is pre-tensioned around the roller. The elastic deformation of the tensioned web is described by the large-deflection bending of thin plates equations, considering its non-negligible bending stiffness. A Fischer–Burmeister complementarity condition captures the contact mechanics between the tensioned web and the roller. The governing equations combine in a coupled elastohydrodynamic lubrication model, which is fully described by a set of non-dimensional numbers. These are used in a parameter study to investigate the effect on the pressure and film height distributions. It is shown that the bending stiffness of the tensioned web results in an additional hydrodynamic pressure peak and corresponding minimum in the film height, near the inlet of the roller contact. An increase of the bending stiffness corresponds to a decrease in film height. The numerical results are compared with benchmarks from literature and experimentally validated with layer height measurements from flat layer imprints. Good agreement is found between the numerical and experimental results.

Preparation of cellulose nanoparticles/epoxy resin composites using the in-situ reaction method for strengthening and toughening epoxy resin film simultaneously

To improve the mechanical properties of epoxy resin (EP), cellulose nanoparticles (CNP)/EP composites were prepared using an in-situ reaction method. Fourier-transform infrared spectroscopy analysis showed that cellulose nanocrystalline (CNC) decomposed into CNP in the reaction, and grafted with epoxy resin E44. Environmental scanning electron microscope analysis showed that the CNP had good interfacial compatibility and dispersion in the EP. TEM analysis showed that the CNC decomposed into CNP during the process of copolymerization with epoxy resin E44, and the size of the CNP was around 50–100 nm. With the addition of 0.3 wt% CNC, the tensile strength of the CNP/EP composite film increased by 24%, the tensile modulus increased by 26%, the elongation at break increased by 61%, and tensile toughness increased by 101%. Therefore, in this work, we presented a novel cellulose nanoparticle to simultaneously strengthen and toughen epoxy resin.