Papers by Keyword: Polymer Composite

Abstract: The paper develops a predictive model to determine the influence of the value of the dispersion component of the free surface energy (FSE) and the volume fraction of fillers on the dispersion component of the FSE of a polymer composite. Mathematical equations and graphical relationships illustrating these relationships are presented. The model is based on the assumption that in composites the FSE value is partially determined by interactions at the polymer-filler interface. Using the predictive model, it was established that the dispersion component of the free surface energy (FSE) can be a reflection of the properties of polymer composites. The reliability of the predictive assessment is shown on the example of an epoxy polymer composite with various mineral fillers.

Abstract: This study investigates an enhancement of carbon-based materials, including multi-walled carbon nanotubes (MWCNTs) and graphite, through Ion Assisted Reaction (IAR) and metal nanoparticle deposition using Physical Vapor Deposition. The IAR process employed Ar⁺ ion beams in reactive gas environments, effectively introducing hydrophilic functional groups such as hydroxyl (-OH) and carboxyl (-COOH) on the MWCNT surfaces. This modification significantly improved dispersion behavior of the treated MWCNTs, particularly in non-polar solvents like N-Methyl-2-pyrrolidone (NMP). Results indicated that the treated MWCNTs demonstrated a slower sedimentation rate compared to untreated samples, with enhanced stability over 120 minutes in NMP. Graphite was modified with copper nanoparticles on its surface using magnetron sputtering in PVD system, leading to a uniform distribution of the modified graphite in matrix. SEM analysis revealed that this modification enhanced the surface roughness of the graphite, facilitating stronger interfacial adhesion with polymer epoxy resin. Composites incorporating these nanoparticle-coated graphite fillers (NPP graphite) exhibited superior thermal and mechanical properties. For instance, a 15% increment in thermal conductivity was observed in epoxy resin composites containing NPP graphite compared to those with untreated graphite. This improvement was attributed to the metallic Cu nanoparticles acting as thermal bridges, effectively transferring heat within the composite matrix. Mechanical properties were evaluated by blending modified fillers into polymer matrices, including polyvinyl chloride (PVC) and polyethylene (PE), with filler concentrations varying from 5 vol% to 15 vol%. Tensile testing and SEM analysis of the fractured surfaces indicated that NPP graphite composites achieved uniform dispersion, reduced agglomeration, and improved interfacial bonding. This study demonstrates that physical surface modification techniques such as IAR and PVD effectively overcome limitations associated with conventional chemical methods. This approach not only improves the dispersion and interfacial adhesion of carbon-based fillers but also enhances their thermal and mechanical performance.

Abstract: The concept of developing a bamboo-based Nylon 66 polymer matrix composite is a relatively novel and very new technical attempt through friction stir processing (FSP). This innovative approach can create a composite material that strengthen the mechanical properties of bamboo and the versatility of Nylon 66. However, successful implementation requires careful consideration of FSP process parameters such us tool rpm, traverse speed, tilt angle and tool design. Among the processing parameters, the tool rpm shows the significant role for severe plastic deformation and temperature generation which leads to the achieving excellent bond. Therefore, in this present study attempt has made to develop the polymer matrix composite (nylon 66 and bamboo powder) using FSW process at a variant rotational speed of 300,400 and 500 rpm with the constant traverse speed of 25 mm min^-1. The deformation behavior and the peak temperature evolved under the tool shoulder during the stirring motion is studied using COMSOL Multiphysics simulation. It is found that, the specimen processed with higher rpm (500rpm) shows the higher volumetric strain and the peak temperature and it is evident that with increasing rpm the higher amount of severe plastic deformation occurred. Initially the process parameters are optimized without bamboo powder on the nylon 66 plate of 6 mm thickness and found that the 500 rpm processed specimen shows the defect free. Prior to the actual FSP, the small keyways taken on the center of the nylon 66 plate in order to add the bamboo powders in it. Actual processing was done with bamboo powder after adding natural bamboo powder of size 50µm. The result reveals that, the bamboo powder has partially expelled out during the period of FSP. This complete study concedes that the processing parameters needs to be optimized and also bamboo added method need to be studied for the successful development of bamboo-based polymer matrix composite.

Abstract: Environmental issues over the eventual fate of post-consumer polymers can be dealt with in two separate ways which is recycling or using biodegradable polymers. However, it is evident that recycling polymers from post-consumer polymers can decrease the mechanical properties over time. Hence, to strengthen the recycled polymers, integrating fibers, such as luffa, into the High-Density Polyethylene (HDPE) matrix, was carried out to produce a fiber reinforced recycled polymer (FRrP) composite. The tensile testing of the FRrP composite shows that the 10% fiber volume fraction (FVF) composite exhibits a higher tensile strength of 3.9% than the neat recycled HDPE (RHDPE). In terms of Young’s Modulus, the 5% FVF of FRrP is shown to have a higher value than the neat RHDPE by 54%. The low density of luffa fibers also contributes to the composites lightweight character. The impact testing shows that the FRrP enhances the impact properties when compared to the neat RHDPE. The peak load, perforation energy, and the total energy absorbed by the FRrP indicate an increasing trend when luffa, of up to 15% FVF, is added as the reinforcement. Thus, the addition of luffa as reinforcement in RHDPE shows significant potential as a high-performance, sustainable, and environmentally friendly material, such as automotive parts and protective gear.

Abstract: Lignocellulosic biomass, such as sorghum stalk fiber, has received a lot of interest as reinforcement in polymer composites because of its renewable nature, low cost, and potential environmental benefits. This is due to crystalline cellulose fibrils embedded in hemicellulose, lignin, wax, and other impurities in the lignocellulosic fiber. As a result, treatment to remove non-cellulosic components, expose cellulose fibrils, and improve the adhesion with polymer matrices is critical for their usage as reinforcement in polymer composites. This study investigates the effects of environmentally friendly steam treatment on sorghum stalk fiber's structural and morphological properties. Sorghum stalk fiber was subjected to steam treatment conditions at different durations. Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and sessile drop tests were used to examine the structural and morphological changes generated by steam treatment. It was observed that the steam treatment of sorghum fiber was successful in eliminating part of the amorphous lignin and hemicellulose components as well as contaminants such as wax, causing the crystallinity ratio to rise. Defibrillation also occurs, and the fiber surface becomes rougher. Due to the rough fiber surface and the space created by defibrillation, the polymer matrix can penetrate the fiber and increase its adhesion by a mechanical interlocking mechanism.

Abstract: Extensive research has been conducted on fiber reinforced polymer (FRP) composites, which have demonstrated superior mechanical properties compared to their individual components. In order to add on to current research trends, the use of ground coffee waste (GCW) and Luffa fibers reinforced polyethylene (PE) composites were fabricated to produce a hybrid natural FRP composite. Tensile testing of the composite indicates that the optimum fiber volume to be between 15% and 35%, as the tensile strength exhibited 9.32 MPa and 8.75 MPa, respectively. Similarly, the tensile modulus of the fabricated composite peaked at 25% with 238 MPa, then declined to 173 MPa at 35%. This indicates that the fibers effectively reinforce the polymer matrix, but once the composite reaches its optimal fiber volume, a decrease in both tensile strength and tensile modulus is observed. The reduction in tensile properties can be attributed to an uneven distribution of load-bearing capacity throughout the composite, as the fibers are no longer able to fully support the matrix once the optimal fiber volume is reached. The specific tensile strength and specific tensile modulus also shows that with the inclusion of Luffa fiber and GCW microfiber contributed to a lighter weight composite. In a nutshell, the hybrid composite fabricated using 25% fiber volume exhibited a tensile strength almost similar to its neat matrix counterpart, though has a noteworthy value in terms of its tensile modulus. The hybrid composite can be as strong in terms of tensile strength, but far more significant in its rigidity, in comparison to the neat polyethylene laminate. Therefore, it showed that the hybrid natural Luffa/GCW FRP has the potential in the engineering industry, such as lightweight furniture, household appliances, automotive parts, and other composite engineering applications.

Abstract: Comparative analysis of two models for predicting residual resource of polymer composite, one proposed by specialists from RS Technologies Inc and the other proposed by Institute of Oil and Gas Problems SB RAS (Russia), was carried out to obtain service life of composite poles for power transmission lines manufactured by RS Technologies Inc (Canada) for cold climate of Republic of Sakha (Yakutia). Models are based on experimental studies of strength of materials during accelerated and full-scale climatic tests. The difference lies in the presence of parameters of climatic zone and test methods in the first model, while the second model considers changes in physical and mechanical properties and structure of materials during aging under conditions of full-scale exposure and accelerated climatic tests. Comparison of results of predicting the durability of fiberglass products in cold climate of Yakutsk (Russia) according to Institute of Oil and Gas Problems SB RAS model and similar products in Calgary (Canada) climate (the closest in terms of climate conditions) according to RS Technologies Inc model showed the same results. Service life of composite support material was approximately 120 years with specified level of permissible decrease in characteristic property index of 75% of the original.

Abstract: The world is evolving toward extending the life of commodities and decreasing waste by recycling. The purpose of this study is to improve resistance of epoxy against the corrosive conditions by reinforcing it with available chemically resistant and low cost materials. Selection of Glass wastes to reinforce epoxy with 50% by weight. Preparation of four sets of samples for this purpose, two sets of samples make and cure at room temperature, while the others cure at 50°C for two hours. Each set make up of both reinforced and unreinforced epoxy. Immersion of these samples in different environment (Water, NaOH, HCl, Benzene and Kerosene) to find out the resistance of the epoxy after reinforcing. After immersion for six months, it is found that the composite seems more resistance compared to matrix material alone. Composites reinforced by glass particles show an increase in mechanical properties when compared to elegant epoxy resin. Density, Vickers hardness and Modulus of elasticity values increased by (31%, 67% and 62%) respectively for composite at room temperature. Improvement of the resistance after the post curing of unreinforced and reinforced epoxy. The solutions that have highest effect for unreinforced samples at room temperature are (HCl and Water). This indicates that epoxy acquire resistance after reinforcing with glass waste which enables it to be utilize in different applications.

Abstract: The development of composites with the waste of industries close to each other would mean an interesting case of industrial symbiosis in search for using less financial and natural resources. This paper presents the development of polymer composites made of three types of waste, produced by industries located in the same region and distant at most 25 km from each other: electronic waste, red mud (obtained during aluminium production), and the waste of wind turbine blades' manufacturing (epoxy resin/glass fibre). Composites were obtained incorporating 5%, 10%, and 15% of industrial waste (red mud and epoxy/fibre) in a matrix of recycled high-impact polystyrene (HIPS) from discarded electronic equipment. Tests were performed to obtain the melt flow index and the composites' water content and study the mechanical properties (tensile and impact) of test specimens produced with the composites by injection moulding (temperature from 200 to 250°C, the injection pressure of 45 MPa, and the injection time of 2.5 s). Results showed that the composites have water content and melt flow index within the specifications for recycled HIPS and are usually more rigid than it, reaching values for Elasticity Modulus up to 34% higher. Therefore, these composites can be applied when materials with more stiffness than HIPS are required.

Abstract: In this work, cellulose was extracted from pineapple leaves by basic hydrolysis and surface-modified by silane coupling agent (Si-69) for use as reinforcing agent in polylactic acid (PLA). The pineapple leaves were subjected to alkali and bleaching treatments to remove hemicellulose and lignin. The corresponding FTIR spectra reveals intensity peaks at 1727 cm^-1 assigned to C=O stretching in hemicellulose, 1614 cm^-1 and 1539 cm^-1 from C=C stretching of lignin and 1241 cm^-1 attributed to C-O stretching of lignin, all of which decreased following the chemical treatments to confirm the effective removal of hemicellulose and lignin. These results were consistent with fiber composition analysis where hemicellulose and lignin both favorably decreased from approximately 20% to 5.46% and 0.47%, respectively, after chemical treatments. However, cellulose content unfortunately also decreased with bleaching cycles despite improving the cellulose yield. The cellulose was effectively surface-modified by 5 wt% and 10 wt% of Si-69 as confirmed with C-O-Si stretching at 1240 cm^-1 from FTIR. As a reinforcing filler to improve PLA performance, cellulose treated by Si-69 were infused into PLA matrix to obtain composite films by solvent casting. As expected, PLA modified with surface-modified cellulose showed the highest value of tensile strength of 21.75 Mpa among the reinforced filler samples and pure PLA, due to a strong adhesion at the interphase of PLA matrix and cellulose.