English Estimating Fatigue of Nr45 Natural Rubber Used in Crank Pulley

Rubber is used as a vibration damper in many engineering applications, especially in the automotive industry. Rubber is used to dampen torsional vibration in internal combustion engines. Therefore, crank pulleys are used to dampen the crankshaft in a certain frequency range. Rubber durability is very important for the crank pulley to perform its duty for a long time. In this study, the dynamic life of NR45 natural rubber with two different mixtures used in crank pulleys was determined by the prepared test approach. A metal-rubber component structure used in the slip test samples was formed and produced. The metal-rubber component is left to force the rubber in the vertical direction with its natural frequency and specified amplitude to simulate torsional vibration in crank pulleys. A test setup design was carried out to force the metal-rubber component at the determined frequency. In the study, life expectancy estimates based on amplitude and frequency were created on experimental data.

Oxidative Destruction of Vulcanized by Changing the Dispersion Composition of Oxidized Vulcanized

The aim of the present work is to study the processes of oxidative destruction of waste vulcanizates (flakes) with nitric acid. The composition of the particles of the main reaction product was determined (oxidized vulcanized). The IR spectra of hexane and acetone extracts of the oxidized vulcanizates are also presented. It was found that the rubber component of the vulcanizates undergoes deep structural changes leading to the formation of products characterized by chemical heterogeneity

Effects of Rubber and Mould Temperatures on the Solid Tire Curing Process

Vulcanization or curing process is a very important process in producing useful rubber products. The quality, performance as well as manufacturing cost of a rubber product are largely affected by the curing process. The curing process takes place when heat is transferred to the rubber compounds inside a heated mould. Curing of a thick article, such as a solid tire, often occurs under transient non-isothermal conditions. The temperature distribution in the rubber significantly affects the cure level distribution throughout the part, especially in a large rubber component. Therefore the ability to predict the distribution of cure level in a rubber part during curing is of great importance for improving the process efficiency and the quality of the final product. In this work, simulations of the curing process of a solid tire, consisting of three layers of different rubber compounds, were performed and the cure level distribution results were evaluated. The simulations are carried out using the commercial finite element software ABAQUS with the cure kinetics model for rubber implemented through the user subroutine UMATHT. The effects of the mold temperature and initial temperature of the solid tire on the cure level distribution and cure time were investigated.

Gas Barrier, Rheological and Mechanical Properties of Immiscible Natural Rubber/Acrylonitrile Butadiene Rubber/Organoclay (NR/NBR/Organoclay) Blend Nanocomposites

In this paper, gas permeability studies were performed on materials based on natural rubber/acrylonitrile butadiene rubber blends and nanoclay incorporated blend systems. The properties of natural rubber (NR)/nitrile rubber (NBR)/nanoclay nanocomposites, with a particular focus on gas permeability, are presented. The measurements of the barrier properties were assessed using two different gases—O2 and CO2—by taking in account the blend composition, the filler loading and the nature of the gas molecules. The obtained data showed that the permeability of gas transport was strongly affected by: (i) the blend composition—it was observed that the increase in acrylonitrile butadiene rubber component considerably decreased the permeability; (ii) the nature of the gas—the permeation of CO2 was higher than O2; (iii) the nanoclay loading—it was found that the permeability decreased with the incorporation of nanoclay. The localization of nanoclay in the blend system also played a major role in determining the gas permeability. The permeability of the systems was correlated with blend morphology and dispersion of the nanoclay platelets in the polymer blend.

DEFORMATION INDEX APPLIED TO IMPACT

ABSTRACT Almost three decades ago, S. Futamura devised the deformation index concept for determining the control parameter for the viscoelastic response of deformed elastomers. We have extended this concept to impact mitigation, wherein material hardness and energy dissipation typically both affect the behavior. Laboratory impact tests were carried out on a series of compounds to deduce the deformation index pertinent to the rubber component. We then analyzed ballistic experiments, wherein material failure is associated with more complex conditions. The utility and limitations of this approach are discussed.

Dynamic Variation of Storage Characteristics and Molecular Structure of Natural Rubber

The quality stability of the natural rubber is a key point to its use in the industries and some special fields. However, due to storage hardening caused by the complicated molecular structure of natural rubber and non-rubber component, the quality uniformity is still not controlled in the nowadays rubber factory. In the previous research, storage hardening phenomena are extensively examined but the special mechanism is controversial and detail information is need to be further revealed. The dynamic evolution of accelerated storage properties and molecular structure of natural rubber have been investigated. The results show that △P increased slowly at first but then increased apparently and PRI has no direct relationship with △P. The storage time of 24 h is the critical storage period in which besides the △P and PRI, the P0, gel content and molecular weight also has obvious transformation. △P has a negative apparent correlation with ester content but protein content is relatively of no account in storage hardening process.

Pressure Sensitivity Enhancement of Porous Carbon Electrode and Its Application in Self-Powered Mechanical Sensors

Microsystems with limited power supplies, such as electronic skin and smart fuzes, have a strong demand for self-powered pressure and impact sensors. In recent years, new self-powered mechanical sensors based on the piezoresistive characteristics of porous electrodes have been rapidly developed, and have unique advantages compared to conventional piezoelectric sensors. In this paper, in order to optimize the mechanical sensitivity of porous electrodes, a material preparation process that can enhance the piezoresistive characteristics is proposed. A flexible porous electrode with superior piezoresistive characteristics and elasticity was prepared by modifying the microstructure of the porous electrode material and adding an elastic rubber component. Furthermore, based on the porous electrode, a self-powered pressure sensor and an impact sensor were fabricated. Through experimental results, the response signals of the sensors present a voltage peak under such mechanical effects and the sensitive signal has less clutter, making it easy to identify the features of the mechanical effects.

Pemilihan Supplier Rubber Parts Dengan Metode Analytical Hierarchy Process Di PT.XYZ

<p>In order to facing an increasingly competitive world of manufacturing industry, it is necessary to select appropriate suppliers to produce quality products at competitive prices. This requires producers to make efficiency. Supplier selection is one way to make efficiency by considering several factors. In this research, the ideal supplier selection is made on rubber component using AHP (Analytic Hierarchy Process) method with three criteria factors that are considered important by the company such as, production factor (48%), quality (40%), and price (12%). Furthermore, this study shows The TRHI as suppliers with the largest value of 51.6% compared to other suppliers such as IKP (24.8%) and IRC (23.6%).</p>

Synthesis and Characterization of NBR´s by RAFT Technique and their use as Rubber Precursor in ABS Type Resins

<p>Different rubbers based on polybutadiene were synthesized in solution by the reversible addition-fragmentation chain-transfer polymerization (RAFT) technique using 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl] entanoic acid as RAFT agent and 1,1’-azobiscyclohexanecarbonitrile (Vazo-88) as initiator. The results obtained in the polymerization of polybutadiene and poly(butadiene-<em>co</em>-acrylonitrile) (NBR) are discussed in terms of molecular weight distribution, composition and microstructure. Composition of polybutadiene in NBR´s was kept constant along the copolymerization, and the vinyl, <em>cis</em> and <em>trans</em> isomers are shown in values of around 12, 26 and 62% in all cases. Resulting rubbers were used to synthesize acrylonitrilebutadiene-styrene (ABS) type resins through an <em>in situ</em> bulk polymerization. Dynamic-mechanical properties and the morphology were analyzed in all the different ABS resins. In DMA analyses, the rubber component presented two transitions as well as an increase in the magnitude of the transition located around -75 °C, which is explained by the significant amount of SAN occlusions in the morphology, analyzed by TEM.</p>