Abstract:Due to the good strength and similar toughness of epoxy resins, vinyl ester resins are widely used as thermoset adhesives in structural adhesive joints and as composites for different industrial applications. However, vinyl ester adhesives are difficult to cure completely under environmental conditions, even after long periods of time because of gel formation slows the necessary diffusion of the catalyst across the polymer network.Several studies have used weathering chambers to investigate the degradation mec… Show more
“…The aging causes only decreasing of the band intensities of the carbonyl C=O and C-O-C of the ester groups. Similar observations were made by Alia et al [64].…”
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.
“…The aging causes only decreasing of the band intensities of the carbonyl C=O and C-O-C of the ester groups. Similar observations were made by Alia et al [64].…”
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.
“…These findings revealed a leger change in the structure of the polyester matrix after aging. 61,62 Figure 11.Tensile strength of composites before and after climate exposure cycles.Figure 12.FTIR spectrum of neat matrix and UP/W composite before and after climate aging test.…”
This work aims to investigate the potential of nonwovens made from untreated (U) and alkaline/bleaching treated (T) palm, wool, and polyester fibers as reinforcing materials in polyester matrix for automotive interior applications. Four needle-punched nonwovens were developed and used with and without chloropropyltriethoxysilane (CPTS) treatment as polyester matrix fillers. Eight composite panels were made using the resin transfer molding machine process and compared to the matrix panel in terms of physical, mechanical, thermal, and climate resistance. The produced composite materials have smooth surfaces and provide consumers with four different aesthetically pleasing finishes. The physical results reveal that the UPalm/Wool and UPalm/Polyester nonwovens lower matrix density from 1223.3 Kg/m3 to 1022.3 and 1040.7 Kg/m3, respectively. The SEM images show that palm fibers are more adherent to the matrix after being treated with an alkaline/bleaching solution. This adhesion is also improved after nonwovens are treated with the CPTS precursor. The composite reinforced with CPTS-treated TPalm/Polyester nonwoven has the highest tensile strength and modulus (72.1 MPa and 3.76 GPa), which are 127% and 36% greater than those of the polyester matrix, respectively. The matrix’s flexural strength and modulus are also enhanced by 148% and 59%, respectively, after reinforcing with CPTS-treated TPalm/Polyester nonwoven. The use of TPalm/Wool and TPalm/Polyester nonwovens as polyester matrix fillers reduces their thermal conductivity from 0.125 W/(m.K) to 0.081 and 0.095 W/(m.K), respectively. Moreover, the climate aging results indicate that composites reinforced with CPTS-treated nonwovens are more stable to climate, implying their applicability and durability in automotive interior applications.
“…After the test, to reduce the sample on the adhesive and to reduce corrosion,dry the sample in the room for 0.5 h ~ 1 h before cleaning, and then surface should be gently cleaned with flowing water with a temperature below 40 °C, to remove salt on the surface of the sample, then with an air pressure from the sample of about 300 mm less than 200 kpa samples should be blow dried immediately (Alia et al, 2018). The experimental results show that this kind of material has strong corrosion resistance and meets the selection conditions of marine engineering equipment materials.…”
Section: Figure 3 Neutral Salt Spray Test Boxmentioning
In order to strengthen the advantages of resin matrix composites such as light weight, high strength, fatigue resistance, corrosion resistance and electrical insulation, glass fiber shows great application potential in the field of Marine engineering. Composite profiles were prepared by pullextrusion process, and the retention rate of mechanical properties was higher after 1000 h test in the neutral salt spray test chamber. The extruded composite profile was used as the frame of the solar module for the Marine environmental test. After a long time of marine environmental testing, the appearance of the component had no obvious defects. The strength retention rate of the composite profile was high, and the maximum power attenuation of the component was less than 5%. The results show that the composite profile can be used as a solar panel frame in marine environment.
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