Papers by Keyword: Unsaturated Polyester

Abstract: Coconut shell (CS) reinforced unsaturated polyester (UPE) composites have been prepared by using hand lay-up and compression molding techniques. To improve fiber matrix adhesion, the CS (30 wt%) was chemically treated by two chemical treatments which are alkaline (NaOH) and alkaline-silane with concentration NaOH (6%) and silane (2%). To enhance the performance of CS-UPE composites, graphene nanoplatelets (GNP) was also added as a nano filler. Scanning electron microscopy (SEM) was used to investigate the morphology of the composite samples. Mechanical properties such as tensile and flexural tests of untreated and chemical treated CS-UPE composites was also studied and compared. Overall, the use of alkalized treated CS-UPE composites showed the best mechanical (strength and modulus). Therefore, alkaline treated CS was selected to be re-prepared with graphene as nano filler in UPE composites at 0.5, 1.0 and 1.5 wt% filler loading, respectively. The presence of GNP in CS-UPE composites have demonstrated a significant enhancement in modulus properties but at the expense of tensile strength. The use of 1.0 wt% of GNP seems more optimize loading since the increment of GNP has reduced the tensile strength, which might be due to the agglomeration issue.

Abstract: Biobased products have been widely used to prevent damage to the environment. In this context, the use of composites reinforced with natural fibers, replacing synthetics ones, has motivated several researches in last years. The objective of the present work was to characterize composites prepared with unsaturated polyester resin and untreated sisal fibers by tensile and flexural tests. The untreated sisal fibers reinforcement was investigated using 25 g and 50 g masses. The fibers were randomly arranged into the resin to mold composite boards, using the compression molding technique without heating, in a curing process at 25°C for 48 hours. The results indicated that composite with 50 g presented better tensile strength (49%), flexural strength (71%) and flexural modulus (137%). The increase of fibers content improved the mechanical behavior of the composite. In addition, the use of natural fibers replacing a portion of petroleum-based resin can increase the sustainable concept of the products and reduce manufacturing costs, because it can be used less resin.

Abstract: Nanocomposite was prepared using unsaturated polyester (UP) resin as a matrix and graphene nanoparticles as a reinforcement material in six percentage weights (0, 0.1, 0.2, 0.3, 1 and 1.5%). Mechanical, calorimetric and thermal studies were performed on the (UP) resin/graphene nanocomposite. All tests showed a clear improvement of all mechanical properties examined (hardness, flexural strength (F.S), impact strength (I.S) and tensile strength (T.S)) with increasing graphene percentage. In addition, the temperature of glass transition and thermal conductivity of this composite increased with increasing graphene content.

Abstract: Bamboo fibers as a natural fiber offer numerous advantages such as high specific strength over synthetic fiber when used as reinforcing fiber for polymer composites. Yet the hydrophilic nature of bamboo fibers with high moisture absorption results in incompatibility in between bamboo fibers and unsaturated polyester resin. An experimental study was carried out to investigate the effects of alkali treatment of bamboo fiber on the mechanical properties and water sorption properties of polyester composite. The result revealed that, the bamboo fiber polyester composite with 5% Alkali treated bamboo fiber possesses the highest mechanical properties. Besides, Alkali treated fibers composite showed a significant reduction in moisture uptake compared to untreated fibers, where composite with 7% Alkali treated showed the lowest moisture uptake.

Abstract: This paper presents flexural properties related to vibration behavior of jute reinforced polyester composite. The goal of the research is to seek green composite material that exhibits good strength and flexural properties along with good damping property designed for wind turbine blades. The material for reinforcement in the present study is jute fiber. The material for matrix is polyester resin. Glass and carbon fiber are used for hybridization. Specimens were fabricated by vacuum infusion technique. Laminates were constructed by stacking jute fiber clothes. Hybrid laminates were fabricated by stacking jute clothes covered by one ply glass cloth and jute clothes covered by one ply carbon cloth. Static flexural and free vibration tests were carried out to obtain the elastic modulus and vibration behavior of specimens, respectively. The result shows that the configuration of jute fiber cloth and glass fiber hybridized laminates possesses compromised properties between flexural properties and damping ratio.

Abstract: This study focused on the examination of unsaturated polyester resin based continuous glass filament mat reinforced composites (GFRP) and the modification by core-shell rubber particles (CSR). The goal was to evaluate the effect of CSR toughening on processability, mechanical properties and impact strength as well as the interaction with inorganic color particles in the submicron range on the GFRP. The interlaminar fracture toughness G_Ic of the modified GFRP was improved by about 20% compared to the neat GFRP by using only 2 wt-% of the CSR modifier, while only marginally increasing the viscosity of the reactive mixture. The responsible mechanisms were found to be local shear yielding of the matrix and an improved fiber-matrix adhesion. The hybridization of inorganic color particles and CSR reduced the interlaminar fracture toughness of the laminate, which could be ascribed to the formation of pores due to the introduction of the oxide particles. However, the impact behavior of the GFRP was positively affected.

Abstract: In this study carbon fibre reinforced epoxy, unsaturated polyester, and vinyl ester based, binary (two-component) hybrid matrix polymer composites were produced and mechanically characterized by interlaminar shear tests. Fracture surface of tested composites were investigated by scanning electron microscopy. Toughness of hybrid matrix composites were identified and compared to that of the reference, non-hybrid matrix ones.

Abstract: A solid buoyancy material (SBM) for deep sea was prepared with a new unsaturated polyester as the base resin, the hollow glass microspheres (HGM) as filler and some other additives. The new kind of unsaturated polyester resin (IPP-UP) was prepared with itaconic acid, isophthalic acid and propylene glycol as the raw materials, on the main chain of which the unsaturated double bonds exist as pendant groups. The hollow glass microspheres are purchased from 3M Company, USA, with the density of 0.42g/cm³ and compressive strength 55.2MPa. By adjust the amount of the hollow glass microspheres, samples of SBM for deep sea with different densities, water absorptions and compressive strengths were made. Studies have shown that, when the filling amount of HGM reaches 60% of the base resin system mass, the buoyant material exhibits excellent low density, low water absorption and high compressive strength which are 0.62g/cm³, 0.59% at 20°C for 24 hours and 67.5MPa.

Abstract: In this work we evaluated the mechanical characterization and sorption water of polymer matrix composites reinforced with sisal fibers at different bath temperatures. Experimental tests of tensile (ASTM D 3039), impact (ASTM D 256) and water sorption in samples with rectangular cross section (dimensions of specimens 20x20mm) were made. It was used the unsaturated polyester resin matrix (Resapol 10-316). With the aim of analyzing the tensile strength and the impact, samples were made with fiber content (by weight) of 44.6%. Water sorption tests were performed with the specimens immersed in water at 25°C, 50°C and 70°C. The results showed that for higher water temperature less time the sample takes to reach saturation and mechanical properties is reduced.

Abstract: In this study, unsaturated polyester resin (UP) is blended with resole type phenolic resin (PF) to develop a material with good flame retardancy. The UP/PF resin blends are expected to show good compatibility when compounded with natural fibers which in this research is kenaf fiber. The thermal properties were investigated by thermogravimetric analysis (TGA). The char yields of the UP/PF blends reinforced kenaf composite increased with PF content. The degradation temperature of the composite at 50% weight loss rose to 410.13°C as the PF content was increased to 40%. The result shows with additional of PF to UP resin enhance the thermal stability of the composite. Meanwhile the mechanical performance of UP/PF kenaf composite were evaluated and compared with neat UP and PF reinforced with kenaf fiber using tensile and impact testing. The mechanical properties of all resin blends at different mixing proportions slightly decrease by increasing the phenolic content but shown an improvement as compared to the PF kenaf fiber composite. The fracture surface morphology of the tensile testing samples of the composites was performed by scanning electron microscopy (SEM).