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Fumarate is an unsaturated dicarboxylic acid useful as a raw material for unsaturated polyester resins, polybutylene succinate (PBS), poly(propylene fumarate) (PPF), plasticisers, and other products. Biodegradable plastics derived from fumarate are an attractive solution to the serious environmental pollution caused by plastic disposal. A new fumarate production from CO2 and biobased pyruvate using enzymes in aqueous media under ambient temperature and pressure is an environmental approach to overcome plastic pollution and achieve CO2 capture, utilization and storage (CCUS). In this work, fumarate production from pyruvate and low-concentration CO2 below 15% captured from the gas phase using 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES)-NaOH buffer solution with a multi-enzyme system consisting of pyruvate carboxylase from a bovine liver (PC; EC 6.4.1.1), recombinant malate dehydrogenase from bacteria (MDH; EC 1.1.1.37) and fumarase from a porcine heart (FUM; EC 1.1.1.37) in the presence of adenosine 5′-triphosphate (ATP) and NADH was investigated. It was found that pyruvate can be converted into L -malate in high yields (more than 80%) directly using 15% CO2 equivalent to exhaust gas as a carboxylating agent using a dual-enzyme system consisting of PC and MDH in the presence of ATP and NADH after 5 h incubation. Moreover, fumarate production from 15% CO2 and pyruvate as raw materials was accomplished using a dual-enzyme system consisting of PC and MDH. [ABSTRACT FROM AUTHOR]

The flammability of unsaturated polyester resins (UPRs) limits their applications. Herein, a reactive P‐ and N‐containing flame retardant (DPET) having triazole and piperazine rings is reported. The 9,10‐Dihydro‐9‐oxa‐10‐phosphaphenanthrene 10‐oxide (DOPO) was used to introduce P atoms, and eugenol was used to import reactive double bonds to DPET. Different ratios of DPET were mixed with a commercial UPR and the thermal, mechanical, optical, and flame retardancy properties were measured. The addition of 15% of DPET into neat UPR led to a decrease in the water contact angle from 70° ± 2 to 61° ± 2. The gel content values of the UPRs were found to change between 97.5% and 89%. The optical properties of the UPR were adversely affected by the incorporation of DPET. The modulus of the DPET‐containing UPRs increased with increasing amount of DPET and 15% of DPET‐containing UPR displayed a modulus value of 1784 ± 86 MPa. When 15% DPET was added to neat UPR, char yields were increased (from 5.6% to 16.6%). Limiting oxygen index (LOI) values increased with increasing amounts of DPET and reached up to 23.4%. Micro cone calorimeter (MCC) test results showed up to a 20.5% reduction in the peak heat release rate (PHRR) of the UPR when 15% DPET was added. [ABSTRACT FROM AUTHOR]

AbstractOne of the main challenges in rubber-metal adhesive is improving the adhesion strength performance with high thermal stability. A novel rubber-steel adhesives based on resole phenol formaldehyde/unsaturated polyester/soybean oil polyol blends were fabricated to tackle this challenge. SEM investigated the morphology of the fabricated blends, while the curing reaction and the components’ interactions were evaluated using FT-IR and XRD. The heat resistance and curing properties were studied by TGA and DSC. The adhesion properties for rubber-metal adhesive specimens were tested at room temperature. The impact of soybean oil polyol modifier addition was investigated on adhesion performance. The curing conditions (touch dry, full curing, and shelf life) and hardness were investigated. It is obvious that polyol improves the heat resistance of the prepared films and enhances their adhesion behavior. The fabricated adhesive exhibits good adhesion and thermal stability due to the integration of chemical cross-linking in the matrix. It can adhere extensively to substrate surfaces via intermolecular forces with small physical movements. Controlling the curing time and delaying the shelf life could be possible for samples that take a long time to cure completely. The designed fabricated adhesive appeared to desired properties of satisfactory rubber-metal adhesion and good thermal stability. [ABSTRACT FROM AUTHOR]

A comprehensive chemistry experiment is recommended. In this experiment, the pretreatment, controllable catalytic degradation, analytical characterization of thermosetting unsaturated polyester resin and gel swelling were mainly included. The students could not only gain the knowledge on the waste plastic pollution, but also get the basic principles and methods of controllable catalysis and gel preparation. The experiment enables students to experience the theory applying to practice and making waste profitable, which helps to enhance students’ interest in chemical experiments and cultivate their comprehensive innovation ability. [ABSTRACT FROM AUTHOR]

The work summarizes an innovative nanocomposite including synthesized copper nanoparticle (CuNP) impregnated wheat straw (WS) (the agronomic waste from an wheat plant) reinforced unsaturated polyester resin has been established. The addition of nanoparticles (NPs) increased the antifungal properties (~11%), durability (~9%), and strength (~39%) of the composites. Therefore, these nanoparticles have been synthesized from a copper chloride dihydrate precursor and they have been impregnated into wheat straw via cationization. This copper‐impregnated wheat straw (CuIWS) was formulated and employed to create a strong and long‐lasting nanocomposite with unsaturated polyester resin. Their morphological, mechanical, chemical, biodegradability (BD), and thermal properties were estimated and relationships were explicated systematically. Particularly, the tensile strength of polyester resin, crude and treated WS (cationized and copper‐impregnated) composites were 11.70, 14.20, 20.92, and 22.34 N/mm2 respectively. Therefore the reinforcement capability for crude, cationized and copper‐impregnated WS composites increased by ~22%, 75%, and 92% respectively. The residual ash was just about 16.23%, 12.04% and 6.56% for copper impregnated wheat straw composite (CuIWSC), Cationized wheat straw composite (CWSC) and untreated wheat straw composite (UTWSC) respectively point to the existence of ~4.1% Cu incorporated into the wheat straw which holds up the energy dispersive x‐ray (EDX) spectra of ~4.2% copper content. Thermogravimetric analysis (TGA) indicates that the nanocomposites are stable up to 325°C. These nanocomposites also show superlative crystallinity compared to other ones. Water uptake capacity followed typical Fickian diffusion law. The developed nanocomposites might be suitable for automobile and aircraft parts, furniture, and other indoor to outdoor applications. Highlights: TS of the composites increased by increasing the WS filling up to 15%.The crystallinity increased after the addition of nanoparticles.The typical water uptake properties followed the Fickian diffusion rule.Incorporation of nanoparticles increased 11% antifungal properties.The developed nanocomposites are used for inside and outside applications. [ABSTRACT FROM AUTHOR]

In this study, two characteristics of boehmite nanoparticles (BNs) were used to improve the dynamic‐mechanical properties of pure unsaturated polyester resin (Neat UP). (1) Boehmite's ability to target free radical control in the radical curing reaction of UP resin, and (2) adsorption of alkyd chains and creation of attractive interactions with the resin network. X‐ray diffraction (XRD), Fourier‐transform infrared spectroscopy (FT‐IR), and field‐emission scanning electron microscopy (FESEM) analysis were used to identify the synthesis of particles. The results of FESEM analysis showed that the average particle size was 80–100 nm. TGA was used to investigate the thermal properties of the Neat UP and UP resin containing 0.3 wt% BNs (UP 0.3 BNs). The results of the dynamic‐mechanical analysis showed that the elastic modulus of the UP 0.3 BNs composite increased by 42% compared to the Neat UP. To investigate the significant increase observed in the dynamic‐mechanical properties, the curing kinetics were investigated by differential scanning calorimetry (DSC). Investigating the activation energy in terms of the conversion degree showed earlier dominance of the diffusion phenomenon in the UP 0.3 BNs composite. Investigating the diffusion factors provided by Vyazovkin–Sbirrazzouli showed a significant decrease in K and ED in the UP 0.3 BNs composite (−10.5, 19 kJ/mol) compared to the Neat UP resin (−9.5, 40 kJ/mol). Highlights: Targeted control of free radicals increases network regularity of the UP/BNs.Impressive improvement of mechanical properties of UP/BNs compared to Neat UP.Increasing diffusion phenomenon dominance of UP/BNs system compared to Neat UP. [ABSTRACT FROM AUTHOR]

Highlights The development of high‐performance ultra‐high molecular weight polyethylene (UHMWPE) fiber laminate is of great significance in the field of bulletproof materials. However, due to the poor heat resistance of UHMWPE fibers, it is challenging to achieve exceptional mechanical properties in laminates prepared via hot‐pressing. In this study, we employ a self‐made ultraviolet (UV) cross‐linked fully drawn yarn of UHMWPE (UVFDY), which exhibits excellent heat resistance, to prepare a UVFDY/unsaturated polyester resin (UPR) laminate through hot‐pressing. The laminate possesses outstanding mechanical properties, which includes high Barcol hardness (~40 HBa), high tensile strength (~800 MPa), and high storage modulus (~13.7 GPa at 25°C), surpassing those of most conventional UHMWPE fiber laminates. Its remarkable mechanical properties are primarily attributed to the highly cross‐linked networks of cured UPR and the stable structures (gel content ~89%, crystallinity ~81.5%, orientation ~93%, and smoother fiber surface) of UVFDY during hot‐pressing. This work not only provides valuable insights into the preparation of high‐performance UHMWPE fiber laminates but also promotes applications for the self‐made UV cross‐linked UHMWPE fiber. Novel laminate possesses high Barcol hardness. The tensile strength and storage modulus of novel laminate are excellent. UV irradiated fiber with high structural stability during hot‐pressing. [ABSTRACT FROM AUTHOR]

An attempt has been made to optimize areal density and number of layers of needle-punched jute nonwoven fabric for the development of a rigid composite with desirable performance properties using Taguchi L9 experimental design. The hand lay-up followed by compression molding protocol was used to prepare composite sheet with jute nonwoven fabric as reinforcement and unsaturated polyester resin as matrix. We evaluated the tensile strength, flexural strength, and volume of reinforcement of the developed composites, and analyzed the data in Minitab 18.0 software to optimize the processing conditions. Results inferred that the areal density of jute fabric reinforcement positively influenced the mechanical properties of the composite sheet, while the number of layers had a negative impact. Statistical analysis revealed that 400 GSM jute nonwoven fabric in three layers could be an optimum condition to develop a rigid composite sheet with the desirable properties of an automobile product. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Tiangong University is the property of Journal of Tianjin Polytechnic University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Previous studies have reported that the mechanical properties of GFRP, composed of E-glass and unsaturated polyester resin, decrease when subjected to 70 or more thermal cycles ranging from -5 to 40°C (14 hours per cycle). However, there are reports suggesting that the surface temperature of in-service GFRP bridges can exceed 70°C during summer. This indicates that current data on temperature ranges during thermal cycling tests might be insufficient. This study, therefore, investigates the effects of temperature cycling at elevated temperatures on the mechanical properties of GFRP by conducting cycles from -5 to 75°C. Results from the high-temperature range revealed that the strength of unidirectional materials increased in both tensile and bending tests. Conversely, the mechanical properties of bi-directional materials remained relatively unchanged in both tests. Additionally, a slight mass loss in the specimens was noted due to temperature cycling. This suggests that a reduction in water content within the specimens might be a major factor contributing to the observed strength increase. [ABSTRACT FROM AUTHOR]

β‐Myrcene, a terpenic monomer, holds potential for developing sustainable polymer‐based materials with enhanced properties. This study examines the synthesis of a myrcene‐based monomer and its incorporation into unsaturated polyesters, focusing on polymerization, curing, and final properties. Unsaturated polyesters were synthesized with varying myrcene‐based monomer content (6, 12, and 24 mol%), phthalic anhydride, maleic anhydride, propylene glycol, ethylene glycol, and diethylene glycol. Polymerization achieved conversion values of 0.92–0.93, resulting in polyesters with molar masses between 1400 and 1700 g mol−1 and dispersity indices of 2.0 to 2.3. Nuclear magnetic resonance (1H NMR) demonstrated short branch formation in myrcene‐modified polyesters and a high maleate‐to‐fumarate isomerization rate (92.66%–95.7%), affecting carbon–carbon double bonds per polyester mole (2.27 to 4.28) and final resin performance. Rheological analysis in a styrene solution (70/30 wt%) indicated shear‐thinning behavior, with viscosities ranging from 0.59 to 3.8 Pa·s, suggesting branching affects chain entanglement. Differential scanning calorimetry (DSC) revealed decreased curing enthalpy with increasing myrcene content, and it was inferred that myrcene's double bonds did not participate in curing. Glass transition temperatures of cured polyesters (70–107 °C) correlate with enthalpy trends. Thermal stability of myrcene‐modified polyesters is similar to the reference polyester, highlighting myrcene's potential as a sustainable monomer for customizable unsaturated polyesters. [ABSTRACT FROM AUTHOR]

This paper presents two methods for deformation energy or dynamic for measuring and calculating the torsion modulus, G, for composites with hollow glass microsphere (HGM) additives in unsaturated polyester resin. First, we constructed a measurement system with a torsion pendulum, a force sensor (FS), and a rotational movement sensor (RMS). Then, we deduced a relationship between force (F) and torsion angle (θ) to obtain G by deformation energy. Second, using the relaxation curve, θ in function time (t), we deduce an equation that could return the value of G for dynamic. Both techniques are non-destructive and independent of knowing the value of Poisson's ratio. We used samples of approximately 5.00 mm diameters, and the influence percentage of HGM additives differed from that of 100%Wt resin. They obtained G values by opting for these composite materials' different methods, showing a maximum deviation of 5.44%. [ABSTRACT FROM AUTHOR]

The flammability levels, flame retardancy ratings, and reaction-to-fire (fire response) properties (under five radiant heat fluxes, i.e., 15, 25, 35, 50, and 75 kW m−2) for same real E-glass fiber-reinforced unsaturated polyester resin (UPR) composite wind turbine blade (WTB) samples were determined by experimental techniques like limiting oxygen index (LOI), vertical flame test (VFT), and cone calorimeter test (CCT). Based on typical CCT results (main test parameters), thermal and non-thermal hazard assessment index systems were selected, calculated, and compared to deduce corresponding hazard characteristics of the blade samples. The WTB shows a LOI value of 25.10% (combustible) and a non-rated (NR) UL (Underwriters Laboratories) 94 classification according to the after-flame time criterion. CCT analyses indicate that higher external heat fluxes correspond to increased peak heat release rate (PkHRR), total heat release (THR), and mass loss rate (MLR) values, and reduced ignition time (tig), flame duration (tfl), and overall flame (combustion) duration (FD) values. Meanwhile, CCT analyses indicate that higher external heat fluxes result in elevated specific extinction area (SEA), rate of smoke released (RSR), total smoke released (TSR), CO yield (COY), and CO production rate (COP) values, and relatively lower CO2 yield (CO2Y) and CO2 production rate (CO2P) values. These results reflect real WTB fires will pose severe situations with noticeable thermal and non-thermal hazards. Multiple physical and chemical evolution processes undergo in burning processes of such fires with higher PkHRR values through heat releases, transfers, exchanges, and feedback. Composite blade materials may be largely deformed and disintegrated in faster rates. Burning blade blocks may form spotting fires and cause secondary ground fires. Local air quality, visibility levels, working, and health conditions of related persons may be worsened. It is really urgent to develop mature, effective, novel, and even revolutionary fire protection and suppression technologies for such fires. [ABSTRACT FROM AUTHOR]

Highlights The influence of filling by iron‐containing fillers on the heat release kinetics and mechanical properties of industrial unsaturated polyester resin PN‐1 is investigated experimentally. The iron ore concentrate, electrostatic precipitator dust, high alumina cement grade HAC‐1, shavings made of cast iron, fine grade sand are used as fillers. To improve the strength characteristics of polyester resin composites the small amount (0.2–1.0 wt%) of organosilicon additives such as synthetic silicone rubber, tris(trimethylsiloxy) phenylsilane, octamethyl cyclotetrasiloxane are used. The heat release kinetics is studied for different ratios between accelerator (cobalt naphthenate) and initiator (cyclohexanone peroxide). The time to reach the maximum temperature of the heat release is significantly reduced when a large amount of iron ore concentrate is used as filler. The temperature of maximum heat release decreases and the time to reach it increases when adding electrostatic precipitator dust in small amount of 5 wt% to the high filled by iron ore concentrate (295 wt%) composite system. The optimum in strength indicators associated with the ratio of different fractions in systems consisting of two fillers of different properties and granulometric composition is found. The highest values of compressive strength in the cement–iron ore concentrate and sand–iron ore concentrate systems are observed. An increase in the strength characteristics of composites by 15%–20% with organosilicon additive introduction is observed. The addition of the silicone rubber increases the strength properties of samples the most among all additives considered. Effect of filling by iron‐containing fillers on the heat release kinetics and mechanical properties of polyester resin is found. The time to reach the maximum temperature of the heat release is significantly reduced when the resin is filled by a large amount of iron ore concentrate. The temperature of maximum heat release decreases when the electrostatic precipitator dust in small amount is added to the high filled by iron ore concentrate. An increase in the strength characteristics of composites by 15–20% with introduction of organosilicon additives is observed. [ABSTRACT FROM AUTHOR]

Unsaturated polyester resin (UPR) systems are extensively used in composite materials for applications in the transportation, marine, and infrastructure sectors. There are continually evolving formulations of UPRs that need to be evaluated and optimized for processing. Differential Scanning Calorimetry (DSC) provides valuable insight into the non-isothermal and isothermal behavior of UPRs within a prescribed temperature range. In the present work, non-isothermal DSC tests were carried out between temperatures of 0.0 °C and 250 °C, through different heating and cooling ramp rates. The isothermal DSC tests were carried out between 0.0 and 170 °C. The instantaneous rate of cure of the tested temperatures were measured. The application of an autocatalytic model in a calculator was used to simulate curing behaviors under different processing conditions. As the temperature increased from 10 °C up to 170 °C, the rate of cure reduced, and the heat of reaction increased. The simulated cure behavior from the DSC data showed that the degree of cure (α) maximum value of 71.25% was achieved at the highest heating temperature of 85 °C. For the low heating temperature, i.e., 5 °C, the maximum degree of cure (α) did not exceed 12% because there was not enough heat to activate the catalyst to crosslink further. [ABSTRACT FROM AUTHOR]

The aim of the study was to experimentally verify the enhancement of certain mechanical properties of a composite material consisting of unsaturated polyester matrix reinforced with fiberglass, by incorporating specific proportions of sodium aluminosilicate (SAS) powders and talc as fillers for the fabrication of large wind turbine blades. Samples composed of these materials, with varying combinations of the added components, underwent testing for tensile and bending strength, and experiments were conducted to determine their modulus of elasticity. The findings indicate that the inclusion of SAS in the matrix material resulted in increased values of tensile strength and modulus of elasticity up to certain proportions. Solely adding talc to the matrix material led to a rise in bending strength. Increasing the talc percentage in the matrix material reinforced with 20% fiberglass resulted in decreased tensile strength and elastic modulus of the samples, while incorporating a blend of SAS and talc into the matrix material reinforced with 20% fiberglass significantly boosted the elastic modulus and tensile strength of the samples under tensile conditions. [ABSTRACT FROM AUTHOR]

Highlights The main limitations of using natural fibers reinforced unsaturated polyester (UPE) composites is poor impact damage behaviors. This work focuses to improve impact damage resistance and residual strength of needle punched banana and pineapple fibers UPE composites by hybridization and incorporating stainless steel (SS) mesh. Different configurations such as banana/UPE (PB), pineapple/UPE (PP) and banana/pineapple/UPE (H) composites were fabricated. Later, SS mesh was incorporated in PB, PP and H composites which are denoted as BS, PS and HS respectively. All specimens were impacted with incident energy of 3.5 and 15 J using Fractovis instrumental low velocity impact tester at 2 and 4 m/s respectively. Subsequently, residual strength of impacted specimens was estimated using three point bending test. Results reveal that the HS composites have least residual dent of 0.89 and 3.9 mm and maximum contact force of 1507 and 1959 N were obtained under the impacted velocity of 2 and 4 m/s respectively, which indicated better damage resistance followed by PS, PP, BS, H and PB specimens. Similarly, the least absorbed energy of 1.9 and 12 J observed in HS composites showed better impact damage tolerance. Moreover, the damage degree and performance index were computed and validated with obtained results. The least reduction of residual strength of 1.2% and 3.2% in HS composites confirmed the better impact damage resistance as compared with all other configurations. Finally, microstructural analysis was performed to correlate the impact induced damage mechanisms. HS composites exhibited the least residual dent of 0.89 mm Impact load bearing capacity of HS composites was drastically improved by 280% Strong interfacial adhesion between the banana fiber and SS mesh was observed HS composites showed greater impact resistance under both velocities There is no significant reduction of residual strength in HS composites [ABSTRACT FROM AUTHOR]

This study involves the preparation of polymer composites using untreated and treated chicken feather, leather, and cow hair fiber in combination with unsaturated polyester resin (UPR) and analyzing the effect of gamma radiation on tensile properties. These fibers were incorporated into the resin matrix at various weight percentages (2%, 5%, 7%, 10%, 12%, and 15%). Additionally, the nanoparticle ZnO was added in the composites as filler to improve the mechanical properties. The composites that utilized treated chicken feather fibers yielded superior results in comparison to those that relied on untreated fibers. Prepared composites outperformed neat composites when inorganic components were added as filler to UPR. Composite materials' mechanical properties, particularly their tensile strength and modulus, can be improved by combining cow hair feather and chicken feather mixed fibers with ZnO filler and gamma radiation modification, according to this study. The morphological and spectroscopic analysis provides supporting evidence for the mechanical strength between the fibers and the resin. Ionizing gamma radiation modification of the fiber resulted in superior tensile characteristics. The optimized composites of animal fibers were then subjected to gamma radiation of variable dose of 0, 2.5, 5 and 7.5 kGy. The tensile properties were found to be the maximum at 5 kGy. Scanning electron microscopy was used to investigate the structural changes caused by the incorporation of animal fibers (chicken feather and cow hair) and ZnO. Composite material and UPR functional group identification were achieved by means of Fourier Transform Infrared Spectroscopy (FTIR). [ABSTRACT FROM AUTHOR]

In this study, the structural performance of recycled PET foams that are developed as a core material from PET wastes from core‐kit manufacturing process is studied. Compression molding under heat method is used to manufacture recycled PET cores by using waste PET foam powders. Unsaturated polyester resin is used as a binder to collect and bond PET powders to get a compact form. Binder is mixed with waste PET powder and the blend is compressed under the heat with a pressure in a mold. The various powder/binder mixing ratios as 50/50, 60/40, and 78/22 are used to see effect of mixing ratio on density and flexural strength. Moreover, waste short glass fibers are added to mixture to increase strength of core material. The results reveal that flexural strength and density decreases with the increasing of powder content in mixing. In addition, it is noticed that sandwich composite structure prepared with recycled cores shows better bending and shear properties than those of sandwich composites prepared with virgin foam core materials. The results presented here may serve as utilization of foam core wastes from core‐kit manufacturing process by recycling via compression molding applications. [ABSTRACT FROM AUTHOR]

In this article, we examine the influence of bolt threads on the tensile rupture strength of the net section corresponding to single-bolt double-lap connections in pultruded materials made of dicyclopentadiene-based unsaturated polyester resin reinforced with E-glass fibers in the forms of roving, continuous-strand mats and triaxial fabrics that incorporate chopped strand mats and plies oriented in the 45∘ , 90∘ , and −45∘ directions with respect to the longitudinal direction (i.e., roving direction). Thirty-six single-bolt double-lap connection tests were carried out on plates in which the bolt-hole diameter to plate width ratios were 0.5, 0.6, and 0.75. All these connection tests incorporated finger-tight A307 zinc-coated bolts fully threaded in one case and partially threaded in another case. The results from these experiments revealed that bolt threads in contact with the bolt-hole surface influence the tensile resistance of the net section. This influence is evident as the bolt-hole diameter to plate width ratio decreases. Analysis of our findings highlights a notable discrepancy: current design guidelines in both the United States and Europe can considerably underestimate the net section tensile rupture strength of single-bolt connections made from pultruded materials with an offaxis reinforcement scheme. Recommended design guidelines that can be adopted by practicing engineers are proposed. [ABSTRACT FROM AUTHOR]

This work focused on obtaining a low-temperature powder coating characterized by self-healing properties. To achieve this, acrylic resin, blocked polyisocyanates (bPICs) with 1,2,4-triazole, and unsaturated commercial resin were used. The synthesis of bPICs with triazole enabled the low-temperature curing and reversible Diels–Alder (DA) reaction at 160 °C. The chemical structure of bPICs was confirmed using 1H-NMR. The occurrence of the DA and retro-DA (rDA) reactions in the crosslinked polymer, at temperatures of 60–85 °C and 90–130 °C, respectively, was confirmed using Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), and FT-IR spectroscopy. The self-healing properties of the powder coating were examined using polarized optical microscopy. Additionally, the occurrence of the DA and rDA reactions between triazole and unsaturated polyester resin was investigated through repeated self-healing tests. [ABSTRACT FROM AUTHOR]

This research aims to enhance traditional glass fiber composites by utilizing a mediumreactive unsaturated polyester resin (UPR) synthesized from ortho-phthalic anhydride. The UPR is formulated using unsaturated acids, glycols, and styrene monomers, with the reaction tailored to improve mechanical properties beyond those of standard commercial resins. The liquid resin's properties are evaluated for manufacturing viability, and its solidified form demonstrates superior performance compared to industrial benchmarks. The composite, produced via the hand layup technique, features a reduced resin-to-glass fiber ratio. Mechanical property tests confirm its robustness. Additionally, scanning electron microscopy (SEM) analysis reveals the microstructural characteristics to study the UPR performance. [ABSTRACT FROM AUTHOR]

Silsesquioxanes (SQs) are mostly used to provide high‐temperature electrical insulation of resins. Here, SQ is used to functionalize unsaturated polyester (UPE) varnish and investigate the effect of functionalization on the thermal and electrical properties of UPE varnishes. The solvent‐free varnish incorporates a reactive diluent to decrease viscosity and a catalyst to expedite hardening, eliminating the need for solvents. Vinyl toluene (VT) and 1,4‐butanediol dimethacrylate (BDDMA) serve as hardening agents, consistent with prior research. Various characterization tests, including Fourier transform infrared, thermogravimetric analyzer, assessment of thermal conductivity coefficient, and determination of electrical volume–surface resistance, are conducted to determine the physical, thermal, chemical, and electrical properties of the synthesized SQ‐functionalized UPE (UPES) varnishes. Results indicate that the UPES–BDDMA varnish demonstrates the highest thermal decomposition temperature at 438.0 °C, while the UPES–VT varnish exhibits the highest electrical volume resistance of 2.85 × 1015 Ω cm. Volatile organic compound levels in UPE coatings range between 4.9% and 5.10% reflecting the growing demand for eco‐friendly products. It is shown in this study that the use of BDDMA and VT reactive monomers in the synthesis of SQ‐functionalized UPE resin and the properties of the resulting varnishes, especially electrical insulation and thermal stability, are improved. [ABSTRACT FROM AUTHOR]

In this research, hollow inorganic microsphere (Q-cel) reinforced unsaturated polyester composite is produced, and its thermophysical properties have been characterized. The thermal decomposition kinetics of the composite obtained at different heating rates and various compositions are modeled using artificial neural networks. Also, the production optimization of the polyester composite has been evaluated using response surface methodology. The study has been repeated for certain heating rates (5, 10, and 20 K/min). Activation energies of polyester composites have been calculated using thermogravimetric data and kinetic methods. Changes in activation energy during the thermal decomposition (4 wt.% Q-cel, 94 wt.% UP, 580–660 K, and 20 K/min) of the composite are compared using FWO (129.4 kJ/mol), KAS (127.6 kJ/mol), and CR (126.5 kJ/mol). According to the results, it is seen that the activation energy goes up as the temperature and Q-cel ratio by the mass increase. When the amount of the filler in the polyester composite increases, the thermal conductivity coefficient also rises. As well as, it is determined that as Q-cel ratio in the mixture raises, the density of the composite decreases and Shore D hardness goes up. A new and original composite has been produced with Qcel-reinforced unsaturated polyester. The density of the composite is low, its thermal stability is high, and its easy processability will provide a great convenience. Modeling the Qcel ratio of the composite with RSM and the activation energy with ANN have been provided fast, efficient and optimum results. With the composite obtained, both lightweight and thermally stable polymer materials will be produced. [ABSTRACT FROM AUTHOR]

Fireproof coatings are the simplest, most efficient, and oldest method for protecting a wide range of flammable products, such as wood. Furthermore, surface ignition is the initial phase, so surface protection is essential to reduce fire propagation. Furthermore, delaying the spread of flames can help to save someone when a fire starts. This project synthesized flame-resistant resin starting from tetraallyloxysilane monomer as a halogen-free monomer, an intrinsic flame retardant co-curing agent. The following step synthesized polyester resin using terephthalic acid as a heat-resistant resin. Unsaturated polyester was used by bulk radical polymerization. FT-IR and 1H-NMR analysis showed the successful synthesis of the desired monomer and polymeric compound. The thermal degradation and flame retardancy of pure unsaturated polyester resin (UPE) and allyloxysilane-unsaturated polyester (AUPE) were investigated by thermogravimetric analysis (TGA/DTG/DSC). The burning test and the thermal stability of the coating layers were evaluated using standard UL 94. Physical properties of resins were evaluated using Heat Deflection Temp tests (HDT) ISO 75-A, ASTM 648, Hardness ASTM D2583, Volumetric shrinkage ASTM 3521, and Water absorption ASTM D570. The results of the tests show the successful synthesis and their flame retardant properties. [ABSTRACT FROM AUTHOR]

The Sidr Leaves Powder (SLP) is full of natural renewable, and cost-free energy resources with excellent heat resistant properties. Mixing natural fillers in conjunction with unsaturated polyester increases the mechanical and thermal features of composites, which eliminates or reduces the need for additional binders. This study probes the outcomes of supplementing Sidr Leaves Powder at different filler concentrations on the mechanical properties (durability, compression, and impact) as well as thermal conductivity accompanied by FTIR spectroscopy characterization of unsaturated polyester composites. Samples were made using hand-lay molding procedures. The consequences reveal that the maximal impact resistance is (2.52kJ/m²), the highest hardness (72.4 N/mm²), and the highest compressive strength about (48.7 MPa). Moreover, the thermal conductivity's value drops to (0.101 W/m.℃). on 25% volumetric fraction. With FTIR spectra, the evidence of alteration in the chemical content and molecular structure of nanocomposites with varying filler content emerged, making the analysis of the composite material properties possible. These outcomes indicate the prospective usefulness of these composites in such fields as furniture manufacturing, especially in case of a couch due to their super properties. [ABSTRACT FROM AUTHOR]

Copyright of Polimery is the property of Industrial Chemistry Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Sheet molding compounds (SMCs) as an alternative material for low-cost and lightweight automotive structural components require special attention to their failure behavior and collision safety. This study aims to analyze the energy-absorbing response and variability of unsaturated polyester matrix SMCs under the range of strain rates from 10−3/s to 500/s through quasi-static and dynamic tensile tests. Additionally, the tensile process and fracture morphology were characterized using Digital Image Correlation and Scanning Electron Microscopy to reveal the underlying rate-dependent failure mechanism. The results demonstrate a pronounced positive correlation between the tensile strength and absorbed energy of SMCs with strain rates. Specially, the absorbed energy exhibits substantial variability, primarily attributable to the plastic damage behavior during the nonlinear phase. A transition in the failure mode from debonding to pseudo-delamination, accompanied by a more extensive failure area at high strain rates, serves as the main mechanism for enhancing the material energy absorption capacity. [ABSTRACT FROM AUTHOR]

A bipolar plate is one of the most important components of a fuel cell with a proton exchange membrane. Due to the requirement to retain high electrical conductivity, superior mechanical qualities, and low production cost, the development of a suitable material for use as bipolar plate is crucial from a scientific and technological standpoint. Graphite based composites are a viable substitute for metal-based BPs because of their superior mechanical qualities, corrosion resistance, recyclability and cost-effective manufacturing processes. In this work, we attempted to prepare graphite-unsaturated polyester resin composites that would satisfy the technical goals set by the US DOE for 2020 while also making sure that dielectric nature and mechanical strength were well-balanced. Specifically, we tried to investigate how the filler to binder ratio affected the mechanical and dielectric characteristics. With an increase in the amount of graphite up to 5%, the composites' hardness and tensile strength climbed linearly whereas the overall elongation diminishes. The composites' flexural and compressive strengths and the total elongation for compressive and flexural strength increases upto 3% graphite and subsequently drops down as the graphite percentage increases. Composites with 1% graphite have the maximum dielectric strength, while those with 3% graphite show the lowest. Based on these findings, we suggest that a composite that contains between 1% and 3% graphite would work well as a bipolar plate. [ABSTRACT FROM AUTHOR]

Vinyl methyl oxazolidinone (VMOX®) is studied as a new reactive diluent (RD) for highly polar unsaturated polyesters (UPs). Molecules with special structure properties are extensively investigated as components for unsaturated polyester resins (UPRs) and thermosets, particularly for high‐temperature applications. Special diols with a cyclic structure like isosorbide and tricyclodecanedimethanol or special diols with side groups like 2‐methyl‐2‐propyl‐1,3‐propanediol and 2‐ethyl‐2‐butyl‐1,3‐propanediol can provide interesting properties. Bio‐based diols such as isosorbide and 1,3‐butanediol improve the sustainability profile. However, UPs based on such special diols have a higher polarity, limiting their solubility in styrene. This demands a RD, which provides adequate solubility and is suitable for high‐temperature applications. Therefore, our study compares the solubility of highly polar UPs based on special diols in styrene and VMOX®. UPs with different formulations, polarities, and Hansen parameters were synthesized and characterized. The solubility sphere of styrene was determined experimentally with the synthesized UPs. The influence of the special diols on the thermoset properties was investigated in dynamic mechanical analysis measurements. In conclusion, VMOX® as a RD enables full utilization of special diols properties due to the wide solubility window. Moreover, a new class of high‐temperature styrene‐free UP resin was developed. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to investigate the effects of nano or inorganic fillers on unsaturated polyester's (UPE) thermal, mechanical, and physical properties. UPE reinforced with nanoparticles shows better properties than the pure polymer itself. Nano or inorganic fillers are used in the polymeric matrix to improve thermal, mechanical and physical properties. Design/methodology/approach: To improve thermal, mechanical and physical properties, UPE resin was modified with silica (S), boron nitride (BN) and S/BN hybrid nanoparticles at different ratios. Viscosity and solids content measurement, Fourier transform infrared spectroscopy, contact angle measurement, scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and thermal conductivity coefficient tests were performed on the samples. Findings: In the SEM analysis, the UPE sample showed a smooth appearance, while all samples containing additives showed phase separation and overall heterogeneous distribution. TGA results demonstrated that the thermal stability of the resin increased in the presence of S and BN additives. According to the results, it was observed that the presence of S and BN additives in the UPE resin and the use of certain ratios improved the resin properties. Originality/value: As a result of the literature search, to the best of the authors' knowledge, no study was found in which BN nanoparticles were included in the UPE resin together with S. [ABSTRACT FROM AUTHOR]

This article presents partially bio‐based unsaturated polyester resins (UPR) based on 2,5‐furandicarboxylic acid (FDCA). Three different FDCA‐based resins are prepared, which are potentially suited as i) general purpose resin (composed of 1,2‐propylene glycol), ii) resin for pultrusion (composed of diethylene glycol and 1,2‐propylene glycol), and iii) resin for pipe liners (composed of neopentyl glycol and 1,2‐propylene glycol). The mechanical and thermal properties of the bio‐based UPR are systematically investigated and compared with analogous fossil‐based UPR composed of phthalic and isophthalic acid, signaling comparable or even better properties for the bio‐based resins depending on the application targeted. [ABSTRACT FROM AUTHOR]

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Unsaturated polyester resins, one of the most important thermosets, are invariably produced from oil-based monomers. Their application is limited in areas where high thermal stability is required due to their low Tg. Besides, these resins contain 30–40% hazardous styrene as a reactive solvent. Therefore, developing bio-based solventless unsaturated polyester resin with medium to high thermomechanical properties compared to petrochemical-based counterparts is important. In order to achieve this, a series of branched bio-based unsaturated polyester resins were synthesized using bulk polymerization method in two steps. In the first step, four different intermediates were prepared by reacting glycerol (as a core molecule) with either isosorbide (diol), 1,3-propanediol (diol), 2,5-furandicarboxylic acid (saturated diacid), or adipic acid (saturated diacid). In the second step, the branched intermediate was end capped with methacrylic anhydride to introduce reactive sites for cross-linking on the branch ends. The chemical structure of the resins was characterized by 13C-NMR. FT-IR confirmed the polycondensation reaction in the first step and the end functionalization of the resins with methacrylic anhydride in the second step. The effect of 2,5-furandicarboxylic acid and isosorbide on thermomechanical and thermal properties was investigated using dynamic mechanical analysis, differential scanning calorimetry, and thermo-gravimetric analysis. Results indicated that 2,5-furandicarboxylic acid based resins had superior thermomechanical properties compared to a commercial reference unsaturated polyester resin, making them promising resins for high-temperature composite applications. For example, the resin based on 2,5-furandicarboxylic acid and isosorbide and the resin based on 2,5-furandicarboxylic acid and 1,3-propanediol gave glass transition temperatures of 173 °C and 148 °C, respectively. Although the synthesized 2,5-furandicarboxylic acid based resins had higher viscosity (22.7 Pas) than conventional unsaturated polyester (0.4–0.5 Pas) at room temperature, preheated resins can be used for making high-temperature-tolerance fiber-reinforced composite. [ABSTRACT FROM AUTHOR]

The increased interest in the use of polymer composites with natural, biodegradable and renewable fillers is the result of increased awareness of the environment. Therefore, the search for new materials that meet the above expectations is becoming a current issue. The article presents the results of research on composites containing pistachio shells (Pistacia vera L.), which are common agricultural waste, with unsaturated polyester resin based on post-consumer recycled poly(ethylene terephthalate) and vinyl ester resin based on bisphenol-A. The environmentally friendly polymeric cobalt solution was used as the accelerator. In order to study the degradation of the composites, accelerated ageing, immersion in various solvents, and high temperature were used. From the obtained results, it can be observed that accelerated aging resulted in the additional cross-linking of the resin, while the filler absorbed the UV light. During immersion, the polymer matrix was degraded in acetone, whereas the incorporation of pistachio increases its water sorption and the plasticisation effect was also observed. The alkali environment initiated the hydrolysis of ester linkages. The vinyl ester resin-based materials were more chemically and thermally resistant than those from the unsaturated polyester. [ABSTRACT FROM AUTHOR]

Polyurethane/2-hydoxyethyl methacrylate (PU/2-HEMA) hybrids with the modifying properties of unsaturated polyester resin (UPR) were prepared through two steps of polymerization. In the first step, polyurethane prepolymers (PUA) were prepared with an NCO/OH ratio of 2.2 by a polyaddition reaction based on isophorone diisocyanate (IPDI), polyoxypropylene glycol (PPG 2000), and PPG 2700. In the second step, the hybrid was prepared by adding and mixing different contents of 2-hydroxyethyl methacrylate (2-HEMA) to prepolymer polyurethane (PUA). The effect of PUA and PUA/2-HEMA hybrid on the physicomechanical properties of UPR films was studied, including viscosity, compressive strength, hardness, thixotropy, and gamma radiation resistance. The addition of PUA/2-HEMA hybrids improved the physical and mechanical properties of UPR more than the addition of PUA owing to the existence of functional groups derived from PUA and PUA/2-HEMA, such as NCO, double bonds, and NH, which can establish cross-linking between UPR and PUA, as well as between UPR and PUA/2-HEMA. The findings demonstrate that the mechanical properties improve with dose, indicating cross-linking involving the double bonds of 2-HEMA, NH, C=O, as well as the ether group over oxidative degradation. However, an increase in 2-HEMA content in PUA hybrids increases the gamma radiation resistance, tensile, and compressive strengths demonstrating that cross-linking leads over oxidative degradation. This is attributed to the formation of the polymeric network as a result of cross-linking between PUA and 2-HEMA as indicated in the experimental results shown in Table 3 and Schemes 2 and 3. [ABSTRACT FROM AUTHOR]