Papers by Keyword: Epoxy

Abstract: Natural fibers are considered as alternative reinforcements in composites due to their accessibility, affordability, renewability and potential positive effects on some properties. Sources of these fibers include bast, leaf, seed and grass. In this paper, untreated tiger grass fiber, which is typically used as material in soft brooms, has been reinforced in epoxy resin with varying loading of 0 %, 5 %, 10 %, 15 % and 20 % by mass of matrix. For the composite manufacturing, the samples were prepared with the use of silicone molds and were subjected to tensile and water absorption tests. Based from the results, the tiger grass fiber reinforcement has provided significant improvements on tensile strength. The sample with 20 % fiber content achieved the maximum strength of 42 MPa which correspond to about 91 % enhancement as compared to the plain sample. This could be associated with the stress transfer between the unidirectional fibers and the epoxy matrix. As for water absorption, all composites only attained minimal mean values that ranges from 0.035 % to 0.063 %. This could be linked to the water-resistant characteristic of the matrix that protected the reinforcing fibers from being exposed directly to water.

Abstract: This article focused on the effect of natural materials on the Mechanical and Physical Properties of Polymer nanocomposite. Fibers and powder underwent treated with an alkaline solution to improve interfacial adhesion. were constructed with the hand lay-up technique with a PMMA/Epoxy blend and natural powders of egg shells and cuttle bone as reinforcements for medical applications in prosthetic arm fabrication. Therefore the cost of raw materials chosen must be important (i.e. economical and cheap for low-income amputees). Consequently, a prosthesis should be comfortable to wear, simple to put on and take off, light weight, long - lasting, and pleasing to the eye in terms of appearance. The polymer mix composition consisted of 25% PMMA and 75% epoxy, together with three distinct concentrations of natural powders (1, 2, and 3 wt.%) relative to the overall composite weight. The cured resin specimen was evaluated for mechanical and physical parameters, including impact strength, flexural strength, hardness, and density. The results demonstrated that the polymer nanocomposite sample achieved peak impact strength values of 12.2 KJ/m² for cuttle bone and 19.48 KJ/m² for eggshell. The flexural strength recorded was 73 MPa for cuttle bone and 71.2 MPa for eggshell, while hardness values were 83.6 for cuttle bone and 83.8 for eggshell at a 3% nanocomposite ratio. Conversely, the other tests of polymer blends (PMMA + Epoxy) using natural fibers (Siwak and flax) attained the highest results. The impact strength of specimens reinforced with siwak fibers significantly exceeds that of specimens reinforced with flax fibers, with flexural strength and hardness of 13.45 KJ/m², 70.6 MPa, and 86.5 shore D, respectively, compared to the base material (PMMA+EP). The density test results demonstrated an elevation in density corresponding to the increasing weight fraction of nanoparticles (eggshell and cuttle bone) in relation to the base material (PMMA+EP). Therefore, these samples may be considered suitable candidates for use as matrix materials that meet the requirements for prosthetic manufacture.

Abstract: In the field of natural fiber-reinforced composites, hybridization of fibers is commonly used to improve the composite’s properties further. Traditionally, this involves the incorporation of secondary fibers to compensate for the limitations of the primary reinforcing material. Recently, the integration of nanomaterials has emerged as a promising approach for hybrid composite fabrication. In this study, Multi-Walled Carbon Nanotubes (MWCNTs) were incorporated into the nito fiber-reinforced epoxy composite for further improvement of the composite’s properties. MWCNTs, when uniformly dispersed, serve as effective nanoreinforcements capable of improving both mechanical strength and thermal behavior. The incorporation of 0.10 wt% MWCNTs resulted in improved impact strength compared to both unreinforced epoxy and nito fiber-reinforced composites. The hybridized composites also exhibited higher peak temperature and overall thermal stability. Water contact angle measurements also indicated enhanced hydrophobicity upon MWCNT addition. However, excessive loading of MWCNTs led to agglomeration and subsequent deterioration of composite performance. These findings highlight the potential of MWCNTs as multifunctional nanofillers in natural fiber-based hybrid composites, offering improved impact resistance, thermal stability, and moisture resistance. Such hybrid systems expand the applicability of natural fiber composites to demanding sectors such as automotive interiors, construction materials, and consumer goods, where improved durability and environmental resistance are critical.

Abstract: This study investigates the impact of voids on the precision and dimensional stability of bonded joints in hybrid CFRP–aluminum assemblies for optical applications. Six CFRP samples were fabricated using filament winding and bonded to anodized aluminum alloy sleeves with DP 190 epoxy. Four samples were cured at 70 °C and two at 20 °C. Dimensional stability was assessed through radial runout measurements at three stages: post-manufacture, after environmental conditioning (including thermal cycling between +70 °C and –40 °C and six thermal shock cycles), and following mechanical resistance tests (shock, bump, and vibration per ISO 9022-3:2015). X-ray computed tomography (CT) revealed frequent defects such as adhesive starvation at joint edges, overflow, and a significant number of voids introduced during mixing. Porosity analysis showed that the presence of voids with equivalent diameters ≥0.5 mm strongly correlated with increased changes in radial runout, suggesting reduced dimensional stability.

Abstract: The purpose of this study is to compare the impact strength of epoxy composites made of basalt fiber reinforced polymer (BFRP) with those that have nanoclay filler. The matrix materials were Epoxy resin (LY556) and Hardener (HY951), the reinforcing material was basalt fiber, and the filler was warmed montmorillonite nanoclay with a volume percentage of 4%. nanoclay was preheated to 45°C for 40 minutes. The fiber of basalt The control group is epoxy composite (N=20). An experimental group (N=20) of epoxy composite reinforced with basalt fiber and 4% nanoclay filler is created using the hand layup technique. The two groups samples are tested. Results are analyzed using the SPSS-V26 statistical tool, the basalt fiber with 4% volume fraction of warmed nanoclay filler epoxy composite shows the better impact strength, the mean significant difference is p<0.048. The impact strength of BFRP composites containing 4% volume fraction of nanoclay is 9.14% higher than that of BFRP composites without filler, according to the study's limitations.

Abstract: In this work, jute and bamboo fiber is used as reinforcement to prepare hybrid composites. The alkali treatment of both the fibers are carried out and the strength of composites prepared with the alkali treated fiber is compared with the composites made from untreated fibers. The bamboo fibers are chopped and pulverized and added to matrix while the jute fiber is used in continuous form. Tensile, flexural, impact, hardness, thermal absorptivity test is carried along with the flammability test. The tensile strength of jute –bamboo-epoxy composite (JBEC) with untreated fibers is observed to be 12.21 MPa while the tensile strength of jute-epoxy composite (JEC) with untreated fiber composite is observed to be 11.72 MPa. Further, the alkali treatment of fiber increases the tensile strength of both the JEC and JBEC by 8%. About 11.12% rise in tensile strength in JEC and 14.35% rise in JBEC is observed due to alkali treatment of fibers. JBEC with alkali treated fibers [JBEC(AT)] shows 42.5HV hardness, while JBEC shows the hardness of 40.2HV. The hardness of JEC increased from 31.3HV to 35.5HV due to alkali treatment. JBEC and JEC with alkali treated fibers [JBEC(AT), JEC (AT)] shows higher thermal absorptivity than JBEC and JEC owing to the fact that higher thermal conductivity of bamboo fibers. The JBEC(AT) shows an ignition temperature of 301°C, while JBEC starts burning at a temperature of 285.6°C. JEC starts burning at 256.56°C and JEC burns by 248.52°C.

Abstract: This study investigates the mechanical properties, water absorption and microstructural analysis of hybrid composites reinforced with Hemp fiber (HF) and Sisal fiber (SF) combined with Silicon Carbide (SiC) particles in epoxy composites. The fibers were treated with 5% NaOH solution for varying durations to enhance their properties. Composite laminates were fabricated using compression molding with different weight fractions of fibers (30 wt%) and SiC particles. The mechanical behaviour of the composites was evaluated through tensile, flexural, and water absorption tests following ASTM standards. The results shows that hybridization with hemp and sisal fibers improves the properties of epoxy composites, with increased hemp fiber content leading to enhanced mechanical performance.These included a tensile strength of 57.82 MPa, flexural strength of 94.7 MPa. The water absorption dipped in 120 hours of immersion in water, with the HFSF/SiC-5 showing the highest water absorption of 6%.The SEM images revealed a homogeneous distribution, fiber pullouts, voids of fibers and filler materials confirmed the presence in the composites.

Abstract: This study explores the potential of Lygodium circinatum (commonly known as Nito vine), an underutilized natural fiber in polymer composites, as reinforcement in epoxy-based polymer composites. With the growing shift toward sustainable alternatives to synthetic fibers, Nito fiber presents an eco-friendly and cost-effective option. Sodium hydroxide (NaOH) treatment was applied to modify the fiber surface, and its effects on the fiber–matrix interaction, thermal stability, and mechanical performance were evaluated. FTIR analysis confirmed the successful reduction of non-cellulosic components such as hemicellulose in the treated fibers. SEM micrographs revealed enhanced interfacial bonding between the NaOH-treated fibers and the epoxy matrix, with reduced signs of debonding. Thermogravimetric analysis indicated improved thermal stability in composites containing treated fibers, as reflected by a higher degradation temperature. Mechanical properties such as tensile and flexural strength and modulus, as well as impact resistance, however, did not exhibit significant improvements, which might also be affected by the variability in the natural fibers and the hand lay-up method. These findings emphasize both the promise of Nito fiber as a viable natural reinforcement and the importance of consistent processing methods in composite fabrication. Overall, this work supports the favorable transition toward natural fibers in composite applications, particularly where thermal performance is prioritized.

Abstract: This work aims to prepare an epoxy basalt powder and apply it as a protective coating for steel. Basalt powder was dispersed in epoxy resin with different doses of 3, 6, 9, and 12% of the epoxy weight. The prepared modified epoxy coatings were applied to the surfaces of carbon steel plates, and the coated samples were evaluated as follows: dry film thickness (DFT), adhesion strength, impact resistance, bending test, abrasion resistance, and fire and chemical resistance. The study revealed that using basalt powder improves the protective performance of epoxy. The obtained results showed that the optimum basalt content is 9%, and the enhancing coating performance of epoxy modified with 9% basalt as compared to neat epoxy was as follows: DFT increased by 50%, adhesion strength enhanced by 85%, and impact resistance increased by 95%. Abrasion and fire resistance were improved by 13% and 30%, respectively. Lastly, the chemical resistance of coatings was changed from fair to excellent. Keywords: epoxy, epoxy basalt coating, steel protection, basalt powder

Abstract: In order to increase the utilization of polymer composite technology, natural fiber reinforced composites are required. Because of its exceptional mechanical qualities, bamboo culm fiber in hybrid composites has drawn the rigorous attention of researchers and producers. Gigantochloa Scortechinii, a particular species of bamboo, was obtained for this investigation from the Bukit Larang hamlet in Melaka, Malaysia. In these trials, a 5 mm thick metal mold was used to manually lay-up epoxy, chopped strand mat, and bamboo fiber. The 355 µm and 500 µm composite bamboo fibers were made. There was a range in the percentage of bamboo fibers from 1% to 5%. After that, the specimens were examined utilizing a variety of methods, including as impact, flexural, and tensile testing. Comparing the 500 µm bamboo hybrid composite to the 355 µm bamboo hybrid composite, the results showed improvements in tensile and impact strength of 22.3–42.3%. For the flexural strength, however, the reverse trend was seen (34.8-36.25%). These results imply that bamboo fiber, which is based on a hybrid composite of chopped strand mat and epoxy, produces outstanding mechanical qualities and can be a good substitute for reinforcing fibers made of composite materials.