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This study compares the degradation process of unsaturated polyester resin (UPR) and vinyl ester resin (VER) and their biocomposites with kraft lignin. In order to study their degradation, accelerated aging, immersion in different solvents, microwave radiation and high temperature were applied. The results show that, depending on the conditions, the degradation assumes a different course. The VER resin is more chemically resistant than the UPR resin. In the case of the composites immersed in an aggressive solvent (acetone), it can be observed that the polymer matrix is degraded, whereas in water only a small increase of weight takes place. Immersion in NaOH initiates the degradation process consisting in the hydrolysis of ester bonds, which are especially observed for pure resins. Under the influence of UV radiation and microwaves, the resins are additionally cross-linked. Thermogravimetric analysis shows that in the case of composites heated to 1000 °C, a residual mass remains, which is carbonized with lignin. In turn, composites treated with microwaves lost weight.

Vinyl ester resins (VERs) are one of the main categories of polymeric matrices for fabrication of high-performance commercial composites. They have more desirable properties compared with unsaturated polyester resins. Inserting urethane functional groups in the structure of VERs and producing urethane vinyl ester resin (UVER) improve its impact and chemical resistance, enlongation and toughness. The use of isocyanate as the primary resource in urethane preparation, which is derived from phosgene toxic material, may be associated with environmental hazards; as a result, non-isocyanate polyurethane (NIPU) methods have been developed. Herein, we have described the preparation and characterization of UVER by isocyanate-free system. First, cyclic carbonates of epoxides, 2-hydroxy-3-(4-(oxiran-2-ylmethoxy)butoxy)propyl methacrylate (HOMBPM) and diglycidyl ether of bisphenol-A epoxy resin (DGEBA) were synthesized by treatment of the corresponding epoxides with atmospheric pressure of carbon dioxide and tetrabutylammonium bromide (TBAB) as a catalyst. Then, the as-prepared cyclic carbonates were reacted with ethylenediamine in the presence of different catalysts to produce non-isocyanate epoxy vinyl ester urethane prepolymer. UVER is a potential compound for curing with VERs and fabricating materials with superior mechanical features such as elongation and tensile strength in comparison to VERs. Characterization techniques such as FTIR, 1 H and 13 C NMR spectroscopy and titration methods for measurements of epoxy equivalent weight (EEW), acid number and amine value are used in the synthesis of the desired compounds. Graphical Abstract

The paper presents the results of research on composites containing wood flour and vinyl ester resins as matrices. One of the resins was a commercially available vinyl ester resin (VER) based on bisphenol A, while the other (VPE)-not containing bisphenol A, was obtained by us in an innovative way protected by a patent, whereas light yellow wood flour (WF) powder was obtained from spruce ( ) and fir ( ). Due to the fact that vinyl ester resins are characterized by large mechanical and chemical resistance, they are used mainly in the form of composites for the production of everyday products. To verify the possibilities of their biomedical applications, our studies focused on the evaluation and comparison of cytotoxicity of both resins using human skin fibroblasts and their resistance to bacterial bio-film adhesion for the aerobic Gram-positive bacteria ATCC 25923, PCM 896 (Polish Collection of Microorganisms), and the aerobic Gram-negative bacteria ATCC 25992.

Total or partial replacement of styrene with low volatilities diluents can be considered the most effective way to reduce the environmental risks and destructive effects of styrene release on human health. In this respect, phthalic acid-derived diluents are ideal candidates to replace styrene because of their easy availability, low volatility, and inexpensive. In the present study, a reactive diluent (D 1 ) was synthesized from dimethyl phthalate (D p ) and hydroxyl ethyl methacrylate (HEMA) to produce a copolymer with epoxy acrylate (EA) resin. Nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) confirmed the chemical structure of synthesized diluents and EA resins. Also, the viscosity, thermal stability, and mechanical properties of EA resin samples were investigated using the rheology test, thermogravimetric analysis, tensile test, and flexural test. The results showed that diluent D 1 (active diluent) is more effective than D p (deactivated diluent) and styrene, especially in reducing the viscosity of EA resins. Overall, the great effect of diluent D 1 in improving the rheological properties (before curing) and the thermal stability and mechanical properties (after curing) of EA resins make this diluent a suitable alternative to styrene in the production of commercial EA resins. Graphical abstract

Ensuring long-term wellbore integrity is critical for carbon dioxide geological storage. Ordinary Portland cement (PC) is usually used for wellbore primary cementing and plug operation, and set cement is easily corroded by acidic fluids, such as carbon dioxide, in underground high-temperature and high-pressure (HTHP) environments, resulting in a decrease in the mechanical properties and an increase in permeability. In order to achieve long-term wellbore integrity in a CO2-rich environment This study introduces materials such as thermosetting vinyl ester resin (TSR), filler composite resin (FCR), and low-cost resin cement (RC). Corrosion experiments were conducted using four materials in 28 days under supercritical carbon dioxide gas and water phase conditions of 60 °C and 10 MPa. The samples were characterized through mechanical property testing machines, core permeability measuring instruments, FTIR, XRD, and SEM. The results proved that after corrosion, PC mechanical properties decreased, the permeability increased, and the microscopic composition and morphology changed greatly. Penetrating corrosion occurs in the sample in the gas phase environment, and propulsive corrosion from outside to inside occurs in the water phase environment. However, TSR, FCR, and RC materials all maintain excellent resistance to carbon dioxide corrosion in gas and water environments. They have higher compressive strength and extremely low permeability compared to ordinary Portland cement. These three materials’ compressive strengths can be maintained around 131, 99, and 58 MPa, and permeability can be stabilized at <6 × 10−7, <6 × 10−7, and 0.16 mD levels. In summary, the above three materials all show better performance than ordinary Portland cement and are promising alternative materials that can be used in primary cementing and plug operations of carbon dioxide geological storage wells.

This study incorporated silane coupling agent KH550-modified nano-alumina (KH550-Al2O3) into vinyl ester resin (VER) for modification. The effect of KH550-Al2O3 on the flexural properties of VER and basalt fiber-reinforced vinyl ester resin (BF/VER) composites was investigated. In addition, dynamic mechanical analysis (DMA) and long-term elevated temperature aging of the composites were performed. The surface functionalization of KH550-Al2O3 was confirmed by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and energy-dispersive X-ray spectroscopy (EDS). It was revealed by scanning electron microscopy (SEM) that the aggregation of KH550-Al2O3 had been reduced within the VER matrix, the resin was effectively enhanced, and the fiber–matrix interfacial bonding was improved. Based on the experimental results, the optimal filler loading of KH550-Al2O3 was 1.5 wt%. Compared with the control group, the resin matrix exhibited 18.1% and 22.7% improvements in flexural strength and modulus, respectively, while the composite showed increases of 9.3% and 7.6% in these properties. At 30 °C, the storage modulus of the composites increased by 11.5%, with the glass transition temperature rising from 111.0 °C to 112.5 °C. After 60 days of thermal aging at 120 °C, the retained flexural strength and modulus were 64.3% and 87.4%, respectively.

Polymer concrete, which contains silica fume powder and vinyl ester resin as two replacements for Portland cement, has improved mechanical properties and durability compared to ordinary concrete. Thus, this kind of concrete is considered to be a high-strength concrete that is resistant to corrosion and chemical attacks. In this paper, the effects of the combination of silica fume powder and vinyl ester resin as two Portland cement replacements on the workability and slump value, initial and final water absorption, compressive and tensile strength, and failure and fracture paths of the polymer concrete have been investigated. All investigations have been based on 16 different polymer concrete mixture designs. The results indicate that the optimum percentages for a combination of silica fume and vinyl ester resin, which has the maximum compressive strength (34.26 MPa) and the maximum tensile strength (4.92 MPa), are a combination of 10% silica fume and 5% vinyl ester resin. To evaluate the durability of polymer concrete, the water absorption of all mixture designs has also been measured. Accordingly, the mixture design, which includes a combination of 15% vinyl ester resin and 5% silica fume, has a minimum initial and final water absorption equal to 0.62% and 1.95%, respectively.

Purpose Phenolic epoxy vinyl ester resin (PEVER) is an advanced resin matrix, which has excellent heat resistance, electrical insulation. However, the brittleness and poor toughness of its curing product limited its application, so this paper aims to modify the PEVER with hyperbranched polyimide (HBPI), so as to enhance the toughness, heat resistance and dielectric properties of PEVER. Design/methodology/approach Hexamethylene diisocyanate trimer was used as the central reactant. Methyl tetrahydrophthalic anhydride was used as the branching unit, stannous octoate was used as the catalyst and hydroquinone was prepared as the inhibitor. Then, the hyperbranched structure of HBPI was characterized by Fourier transform infrared spectrometer and 13C-NMR. Next, PEVER was mixed with different contents of HBPI, and then the authors tested its curing product. Findings It is found that with the addition of HBPI, the free volume of the system was increased and the content of polar groups was decreased in each unit space, so the dielectric constant (ε) and the dielectric loss (tanδ) were decreased. In addition, PEVER could be well toughened by HBPI and the thermal stability of PEVER was improved. Originality/value HBPI has excellent heat resistance. The addition of hyperbranched polymer increases the free volume of the system so it can slow down the transfer of stress and its nearly circular structure can absorb the impact energy from all directions. Moreover, an appropriate amount of free volume can decrease the dielectric constant of PEVER by reducing the content of polar groups.

In the world of composites the mostly used matrix materials was polyester resin and for few application epoxy resins were also used as the matrix element for building up the composite material. In recent days by replacing these polyester and epoxy resins vinyl ester resin show parametric advantages in terms of thermal, physical and mechanical properties of the resultant composites. In this work a brief study on the composites materials with vinyl ester as matrix phase has done to show the advantageous of using vinyl ester resin and the review paper also suggests the usage of vinyl ester resin as effective replacement for polyester and epoxy resin i.e. in which application can the vinyl ester resin used as matrix element for making composite material.

Two-dimensional nanosheets are highly effective tougheners for vinyl ester resins. The toughening effect is related to the high specific surface area and unique two-dimensional planar structure of the nanosheets. In this study, a coupling agent γ -(2,3-epoxypropoxy) propytrimethoxysilane (Kh-560) was used to modify MXene nanosheets (M-MXene) for use in toughening vinyl ester resin. The mechanical properties, including the tensile strength, flexural strength, Young’s modulus and elongation, of neat vinyl ester resin and vinyl ester resin modified with MXene and M-MXene were investigated. The results showed that modification significantly improved the mechanical properties of the vinyl ester resin. The tensile and flexural strengths of the MXene-nanosheet-modified vinyl ester resin were 27.20% and 25.32% higher, respectively, than those of the neat vinyl ester resin. The coupling agent improved the interfacial compatibility between the MXene nanosheets and vinyl ester resin, which resulted in the tensile and flexural strengths of the M-MXene-nanosheet-modified vinyl ester resin being 52.57% and 54.60% higher, respectively, than those of the neat vinyl ester resin for a loading quantity of nanosheets of only 0.04 wt %, which is economically viable. The main mechanisms by which the nanosheets toughen the resin are crack deflection and crack pinning.