Studying of Wear Rate for Ternary Polymer Blends under the Influence of Chemical Solutions (original) (raw)
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Polymer, 1996
A ductile thermoplastic, polycarbonate, has been blended with the diglycidyl ether of bisphenol A (DGEBA) epoxy resin to increase the 'toughenability' of the resin. Cured epoxy-polycarbonate systems showed no increase in fracture toughness relative to the neat epoxy resin. The binary blends were miscible, single-phase systems. Addition of rubber to both the epoxy and the epoxy-polycarbonate blends leads to significant improvements in the critical strain energy release rate, Gic, of the cured resin. The presence of the polycarbonate produced no additional improvement in Gic relative to rubber toughening alone. This is ascribed to a degradation reaction of the polycarbonate occurring during blending. The chemical nature of this reaction is discussed.
WEAR RESISTANCE OF HYBRID BLEND REINFORCED BY FIBERS WITH DIFFERENT MIXING RATIO
The research aims to study the mechanical properties (Hardness and Wear Resistance) of composite materials (epoxy resins with phenolic formaldehyde resin) supported by graphite or silica particles or both, and reinforced with carbon fibers of a standard format (-90, 0, +90).easy INTRODUCTION The main functions of the fiber in a composite are to carry most of the load applied to composite and provide stiffness. For this reason, fiber materials which have high tensile strength and a high elastic modulus are often used for the fiber in composite [1]. Carbon Fibers (CF) appeared in the market in 1960 and are produced from organic fibers (rayon, acrylics, etc.) or from remaining of petroleum or tar distillation. [2]. Carbon fibers are the strongest and stiffest reinforcing fibers for polymer composites, these fibers are the most commonly used after glass fibers. Carbon fibers can give galvanic corrosion in contact with metals. They're generally used together with epoxy, phenols, polyester, where high stiffness and strength are required, i.e. space and automotive applications [3]. Another mechanical property that may be important to consider is the hardness, it is a measure of a material's resistance to localized plastic deformation. Shore hardness is measured with instrument known as a durometer and is also named durometer hardness [4]. In the current study wear test, this method was adopted because it is easy method and can be inference the wear rate because it gives the amount of wear debris. This method is summarized by weighted of the sample before and after the test, and the difference between the two weights represents the amount of wear debris. [6,5]. Carbon has two natural crystalline allotropic forms: graphite and diamond. Graphite derives its name from the Greek word "graphein" [7]. The water solution which contains a concentration of 40% formaldehyde is called formalin. this is used as a preservative for tissues and in embalming, with a boiling point of 21 ° C, it is used in veterinary and in dentistry as well as in the production of chemicals and polymers and is often used in the manufacture of coatings and explosives [4].In general, phenol-formaldehyde produced by two ways, for manufacture two types of polymers, namely Novolac and Resole [15]. Novolac is a type of polymers produced by mixing formaldehyde (37% water solution) with phenol by added an acidic helper (sulfuric, phosphoric or oxalic acid), and heated to the required degree and then equivalent the reaction mixture, and remove the water by distillation (in its final stages under discharge) to a temperature Estimated 160 ° C. Resole is a type is produced by added basic helper with more formaldehyde relative to phenol. Initially, its consists (Oligomer) is called a resole and it is not needed to a hardener (HMTA) but it need just heat treatment [8, 9]. In (2013), Hamid S., studied the mechanical properties (tensile, bending, and hardness) of unsaturated polyester resin reinforced with silica particles in different weight fractions (10, 20, 30 and 40) %. Results showed decreasing in tensile strength and flexural strength with increasing particle concentration, increasing in hardness, tensile modulus and bending modulus with increasing in particle concentration [10,11]. In (2015), Jweeg et.al. designed a new athletic prosthetic foot. The foot was manufactured by using epoxy reinforced by carbon fibers and that gives good mechanical response. The impact tester was designed and manufactured to perform the test. For the same dropped level, the impact response of the samples with glass fiber and carbon fiber have the same peak load for different drop angle but. In addition, it was clear that the responses of the sample manufactured with carbon fiber were more smoothness than the sample manufactured with the glass fiber [12,13]. In (2016), Jagadale U.S. and Raut L.B., investigated the mechanical properties (tensile strength and shear strength) of glass fibers reinforced polymer matrix with different fibers volume fraction (40, 50 and 60) %, hand lay-up and compression molding were used to prepare the samples. Results showed better mechanical properties at volume fraction (50%), further increase in the fiber content leads to increase in the mechanical properties but the composites start to delaminate [14].
Journal of Applied Polymer Science, 1994
The cure process and the mechanical properties of blends of diglycidyl ether of bisphenol-A-based epoxy resin and hydroxyl terminated, internally epoxidized polybutadiene rubber have been studied. Internal oxirane groups are characterized by a main absorption a t 885 cm-' in the infrared spectrum while the terminal oxirane groups of the diepoxide monomer absorb a t 913 cm-'. In the absence of prereaction of the rubber, gelation of the epoxy matrix occurs much faster than any reaction involving the internal oxirane groups or the terminal hydroxyl groups. Therefore, only weak chemical bonding between the rubber particles and the epoxy matrix exists and the fracture toughness of the blends does not show any significant improvement. Upon prereaction of the rubber with an excess diepoxide monomers, a 40% improvement in the value of the critical stress intensity factor is obtained. However, dynamic mechanical spectra of these blends acquired in the rubbery plateau region uniquely demonstrate that this improvement is due to the incorporation of the rubber into the epoxy network rather than to the presence of phase-separated rubber particles. 0 1994 John Wiley & Sons, Inc.
Polymers for Advanced Technologies, 2011
Epoxidized natural rubber (ENR) and thermoplastic polyurethane (TPU) blends were prepared by simple blend and dynamic vulcanization. The main objective was to prepare a low-hardness TPU material with good damping and elastic and mechanical properties. It was found that the incorporation of ENR into the blend shows a reduction in Young's modulus, hardness (i.e. <70 Shore A), damping properties (i.e. tan δ < 0.3), and tension set (i.e. <20%) compared with the pure TPU. This indicates the formation of softer TPU materials with superior damping and elastomeric properties. However, incorporation of ENR sacrificed mechanical properties in terms of tensile strength and elongation at break, but these still remain in the range of applicability for industrial uses. It was also found that dynamic vulcanization caused enhancement of mechanical properties, relaxation, damping, rheological properties, and elasticity of the blends. Temperature scanning stress relaxation measurements revealed an improvement in stress relaxation properties and thermal resistance of the dynamically cured ENR/TPU blend.
Rangsit University, 2014
In this study, the effects of compatibilizer loading on the cure characteristics, thermal and mechanical properties of natural rubber (NR)/synthetic rubber (SR) blends have been investigated. NR was molten and mixed with six synthetic rubbers (butadiene rubber, chloroprene rubber, ethylene-propylene diene rubber, isoprene rubber, nitrile rubber and styrene butadiene rubber) with varied NR/SR weight ratios (100/0, 75/25, 50/50, 25/75 and 0/100) and compatibilizer loadings (0-5 parts per hundred of rubber, phr) on a two roll mill at 70C. The results obtained from differential scanning calorimetry revealed that most of the NR/SR blends both with and without compatibilizer exhibited two glass transition temperatures, indicating that the inclusion of compatibilizers (ENR-25, ENR-50 and Ultrablend-6000) did not improve the compatibility between NR and SRs. However, they could reduce the cure time by 20-50%, as compared to the neat rubber blends, suggesting the reduction in the production energy. Tensile strength of some 50/50 rubber blends with a specific amount and type of compatibilizer improved significantly. Natural rubber/butadiene rubber with 5 phr of ENR-25, natural rubber/chloroprene rubber with 5 phr of ENR-50 and natural rubber/isoprene rubber with 5 phr of Ultrablend-6000 were great examples in terms of improving the mechanical properties.
Polymer Degradation and Stability, 1992
The effects of blend ratio and type of cross-link system on thermal ageing, y-radiation and ozone resistance of blends of natural rubber and ethylene-vinyl acetate (EVA) rubber have been evaluated. The morphology of the blends is such that the EVA forms a continuous phase when its proportion in the blend is 40% or more. The resistance of the blends to thermal ageing, y-radiation and ozone attack is better for those which contain a higher proportion of EVA. These properties are also highly dependent on the type of cure system used.
Wear characteristics of polymer based composites
The dry wear of polytetrafluoroethylene (PTFE)-based composites, including bronze-filled composites (B60), glass-filled composites (G15), and carbon-filled composites (C25), produced by the mold casting method were investigated under different sliding conditions. The Taguchi L27 method and the analysis of variance were used to identify the effect of process parameters on the wear of tested materials. Experimental results showed that the wear resistance of G15 polymer composites was better than those of C25 and B60 ones. The specific wear rate decreased with increasing sliding distance and load, but partly decreased with increasing tensile strength.
Polymer blends of epoxy resin and epoxidized natural rubber
Journal of Applied Polymer Science, 2006
The aim of this research was to investigate the behaviors of epoxy resin blended with epoxidized natural rubber (ENR). ENRs were prepared via in situ epoxidation method so that the obtained ENRs contained epoxide groups 25, 40, 50, 60, 70, and 80 mol %. The amounts of ENRs in the blends were 2, 5, 7, and 10 parts per hundred of epoxy resin (phr). From the results, it was found that the impact strength of epoxy resin can be improved by blending with ENRs. Tensile strength and Young's modulus were found to be decreased with an increasing amount of epoxide groups in ENR and also with an increasing amount of ENR in the blends. Meanwhile, percent elongation at break slightly increased when ENR content was not over 5 phr. In addition, flexural strength and flexural modulus of the blends were mostly lower than the epoxy resin. Scanning electron microscope micrograph of fracture surface suggested that the toughening of epoxy resin was induced by the presence of ENR globular nodules attached to the epoxy matrix. TGA and DSC analysis revealed that thermal decomposition temperature and glass transition temperature of the samples were slightly different.
Studies on the cure and mechanical properties of natural rubber blends
This paper focused on the comparative evaluation of cure characteristics and mechanical properties of blends of natural rubber with dichlorocarbene modified styrene-butadiene rubber and chloroprene rubber with different blend composition. It was found that the Mooney scorch time and cure index shows a negative deviation from the calculated value based on the interpolation between the two component elastomers. However for the blends, modulus and hardness show a positive deviation. The mechanical properties of NR/DCSBR blend are higher than that of NR/CR blends. Flammability, oil and ozone resistance of the blend showed that as the NR content in the blend increases these properties were decreases and also NR/DCSBR blend showed excellent thermal, oil and ozone resistance than that of NR/ CR in entire blend ratios. The mechanical properties, modulus and hardness were also investigated after oil immersion. The changes in mechanical properties were correlated with variation in cross-link density estimated from stress-strain and swelling behavior.