Papers by Keyword: Coupling Agent

Abstract: In this study, the hybridization effect on the mechanical properties of the natural fiber reinforced composites was investigated. For this purpose, glass fibers in different ratios of 2.5, 5 and 10 wt% were added in the polymer composites with cotton fibers at the ratios of 12.5 and 25 wt%. In order to have better interfacial bonding and increase the effectiveness of glass fiber on the mechanical properties, maleic anhydride coupling agent was added in the hybrid composite structures. At the end of the study, the best ratios of maleic anhydride, cotton and glass fiber for this kind composites were explored with respect to the economical and mechanical concerns. This study suggests that hybridization can be considered as most promising way to improve the mechanical properties for this novel composite materials.

Abstract: Producing particulate filled polymer composites, even dispersion and sufficient adhesion between filler and polymer matrix is of great importance. In order to solve these issues, methodologies, such as ultrasonic dispersing and coupling agents, are proposed. The impact of particle surface modification with three different titanate coupling agents having the tradenames of TCA L44, TCA L38 and TCA K44 on paper waste sludge particles surface, polyurethane foam composite density, compressive and tensile strengths as well as water absorption and water vapour permeability is evaluated. Apparently, titanates form layer on the particle surface, thus increasing the interfacial adhesion between particles and polymer matrix. Basing on the obtained results, the optimal amount and type of titanate is 1 wt.% of TCA K44.

Abstract: In this study, novel composites materials composed of polymethyl methacrylate (PMMA) reinforced ZrO₂-Al₂O₃-SiO₂ filler system were developed. Zirconia-alumina-silica filler system were synthesized through sol-gel technique. Chitosan and trimethoxypropilsilane (TMPS) were used to modify the composites system. The resulting composites material were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and hardness test. SEM images displayed the composites particles in nanometer size with minor agglomeration. The XRD results revealed the presence of cubic and tetragonal phase of zirconia and also monoclinic silica phases in the composites system. These crystallographic characteristic could affect the mechanical properties of the composites. The hardness value for un-modified composites was 15.27 ± 0.25 VHN and for TMPS 19.43 ± 1.89 VHN and chitosan modification 18.75 ± 2.05 VHN, respectively. Therefore, these novel composites materials composed of PMMA reinforced filler system of zirconia-alumina-silica would provide the potential to apply in dental technology.

Abstract: Titanium dioxide (TiO₂) is normally added into the rubber compounds as a white pigment and inorganic filler for an improvement of thermal property. TiO₂ is also known to have an outstanding photocatalytic activity. This work investigates the properties of natural rubber (NR) compounds filled with 5 phr of nanoTiO₂ (n-TiO₂). Since the direct incorporation of n-TiO₂ into NR encounters incompatibility problem, therefore two types of coupling agent (i.e. bis-(3-triethoxysilylpropyl) tetrasulfide (TESPT) and isopropyl trioleyl titanate (ITT)) are used. The coupling agent loading is varied in a range of 0-20 wt% relative to the n-TiO₂. Mooney viscosities and minimum cure torque (M_L) of the compounds increase with increasing coupling agent content and the ones with ITT show higher viscosity than the mixes with TESPT. The use of TESPT leads to shorter optimum cure time and higher torque difference compared to the use of ITT. The addition of n-TiO₂ results in the improved modulus, reinforcing index and tensile strength compared to the unfilled vulcanizate. The presence of both TESPT and ITT significantly reduces a photodegradation efficiency. The difference in the properties and photocatalytic activity of n-TiO₂ filled NR having TESPT and ITT as coupling agent indicates their possible different level of dispersion and interactions at the interphases.

Abstract: In this paper, we investigated the effects of a coupling agent (KH560) on the mechanical properties of long glass fiber (LGF) reinforced polyphenylene sulfide (PPS) composites. The LGF reinforced PPS composites were prepared utilizing our self-designed mold. It’s found that KH560 was beneficial for improving the mechanical properties of the composites. Meanwhile, the fiber lengths of glass fibers in the original injection molded sample and near the fracture surface were measured under the optical microscope. Comparing to the untreated sample, the sample with KH560 possessed higher proportion of fiber length on 0.75-1.25 mm. It suggested that KH560 could protect glass fibers from broken. Meanwhile, near the fracture surface, two composites possessed similar proportions of fiber length on 0-0.75 mm. That indicated KH560 improved the interfacial bonding between glass fiber and PPS. Scanning electron microscopy (SEM) images showed that more resin adsorbed on the fiber surface, which was consistent with the above phenomena.

Abstract: New finite element homogenization model with nonaffine constitutive equation of rubber is developed to study the deformation behavior of silica-filled rubber under monotonic and cyclic deformation. The obtained results clarified the effect of the volume fraction of the silica coupling agent and the networklike structure connecting the silica particles on essential physical enhancement mechanisms of deformation resistance and hysteresis loss for silica-filled rubber. The finding suggests that the material characteristics of silica-filled rubber are much more controllable than those of carbon-black-filled rubber.

Abstract: This study uses a single screw extruder to make short coir (SC), an agricultural waste, high-strength short glass fiber (SGF), and polypropylene (PP) into pellets, which are then made into wood plastic composites (WPC) on an injection machine. During the process, maleic anhydride grafted polypropylene (PP-g-MA) is used as a coupling agent to improve the interfacial adhesion between coir and PP as well as between SGF and PP. A tensile strength test, flexural strength test, and Izod impact strength test are performed on the samples to examine the mechanical properties. The experiment results show that when the content of SGF increases from 3 wt% to 12 wt%, the tensile strength increases from 26.08 MPa to 36.68 MPa, and flexural strength increases from 36.01 MPa to 49.91 MPa, but the Izod impact strength decreases from 286.16 J/m to 218.14 J/m. In addition, the addition of 2 wt% of PP-g-MA improves the interfacial adhesion between matrices (PP) and reinforcement (SC or SGF), thereby fortifying the mechanical properties of the composites.

Abstract: Maleic anhydride grafted polypropylene (PP-g-MA) is used as a coupling agent, and the influence of its used amount on the mechanical properties of the polypropylene/short glass fiber (PP/SGF) composites is examined. 1, 2, and 3 wt% of PP-g-MA is separately added to PP/SGF composites that are made at an 80/20 ratio (wt%), made into pellets on a single screw extruder, and then made into test samples on an injection machine. When PP-g-MA increases from 1 wt% to 3 wt%, the tensile strength of the PP/SGF composites increases from 56.22 MPa to 64.85 MPa; likewise, flexural strength increases from 67.29 MPa to 81.24 MPa, and Izod impact strength increases from 197.70 J/m 269.61 J/m. SEM images show that the surface of SGF are encapsulated with a layer of PP matrix, which indicates that PP-g-MA can effectively improve the interfacial adhesion between PP and SGF and thus increase the mechanical properties of the resulting composites.

Abstract: In this paper, empirical models are proposed using multiple non linear regressions technique to predict the influence on the Youngs modulus and the tensile strength of the natural fiber reinforced plastic composites (NFRPC). Maleic Anhydride grafted polypropylene (MAPP) has been a proven coupling agent (CA) used to improve the interfacial bonding between the fibers and the plastics material. It is important to include the factor of coupling agent, when making predictions the properties of the composites through the models. For the development of the model, data was collected from various research journals presented in literature. Non linear regression analysis was performed to obtain the empirical model using polymath scientific software. The results were found to be within the acceptable range.

Abstract: To improve the overall performance of the domestic high-modulus carbon fiber/cyanate composites, a macromolecular coupling agent (SCC) based on the raw material styrene, methyl acrylate and γ-methyl (acryloyl) trimethoxysilane was synthesized. It also studies the effect of coupling agent content on the mechanical properties of composites. The results show that the dosage of macromolecular coupling agent with 3%, the performance of the composite materials has been notable improved, its bend strength and interlaminar shear strength are 1100Mpa and 63.5Mpa, which has been raised 6.0% and 16.1%, respectively. SEM micrographs show that the addition of a coupling agent effectively improve the interface compatibility between the resin and fibers in composite.