The object of this publication is to provide practical guidance on assessing the useful service life of rubbers. It describes test procedures and extrapolation techniques together with the inherent limitations and problems. This Guide seeks to be comprehensive but concentrates on the most common environmental effects causing degradation and the most important mechanical properties of rubbers. The test procedures used are outlined and the relevant d104books and International standards are referenced.
After price and delivery time, the most frequently asked question about a product is 'How long will it last?' Lifetime expectancy is often many years, the service conditions may be complex, and there is a scarcity of definitive data on durability. The situation is complicated by the fact that there are a vast number of degradation agents, service conditions, properties of importance and different plastics. There are many inherent difficulties in designing durability tests. In many cases, the time scale involved is such that accelerated test conditions are essential. Whilst large amounts of durability data are generated by accelerated methods, much of it is only useful for quality control purposes and relatively little has been validated as being realistically capable of representing service. Most assessments of the lifetime of plastics are made by considering some measure of performance, such as impact strength, and specifying some lower limit for the property, which is taken as the end point. Lifetime is not necessarily measured in time. For example, for some products it will be thought of as the number of cycles of use. The object of this publication is to provide practical guidance on assessing the useful service life of plastics. It describes test procedures and extrapolation techniques together with the inherent limitations and problems. The Guide aims to make available the wealth of information that can be applied to help maximise the effectiveness of a durability-testing programme. This guide seeks to be comprehensive but concentrates on the most common environmental effects causing degradation. The test procedures used are outlined and the relevant textbooks and international standards are well referenced. Examples of lifetime testing studies are cited. The Practical Guide will be useful for anyone responsible for designing, manufacturing or testing plastic components. It will also be of benefit to suppliers and users of end products, as assessment of useful lifetime is critical to the economics and safety aspects of any component. Key features Test methods outlined Accelerated testing discussed Prediction methods described Standards cited Key sources of information listed
Rubber components are used in many demanding applications, from tyres and seals to gloves and medical devices, and failure can be catastrophic. This review of Rubber Product Failure outlines and illustrates the common causes of failure, while addressing ways of avoiding it. There has been increasing pressure to improve performance so that rubbers can be used at higher temperatures and in harsher environments. For example, the under-the-bonnet temperature has increased in some vehicles and new medical devices require longer lifetimes in potentially degrading biological fluids. The expectations of tyre performance in particular are increasing, and retreads have been in the spotlight for failures. The definition of failure depends on the application. For example, a racing car engine seal that lasts for one race may be acceptable, but in a normal car a life span of 10 years is more reasonable. If appearance is critical as in surface coatings and paints, then discolouration is failure, whilst in seals leakage is not acceptable. Each rubber product must be fit for the use specified by the consumer. Failure analysis is critical to product improvement. the cause of the problem can be much harder to find. It can range from a design fault to poor material selection, to processing problems, to manufacturing errors such as poor dimensional tolerances, to poor installation, product abuse and unexpected service conditions. The rubber technologist must become a detective, gathering evidence, understanding the material type and using deductive reasoning. Testing and analysis of failed materials and components add to the information available for failure analysis. For example, stored aged tyres appeared superficially to be alright for use, but on drum testing small cracks grew more quickly than in new tyres leading to rapid failure in service. Quality control procedures such as product inspection, testing and material quality checks can help to reach 100 percent reliability. In critical applications such as electricians' gloves for high voltage working, gloves are inspected before each use, while engine seals may be routinely replaced before the expected lifetime to avoid problems. in the literature is not high. However, several reviews have been written on specific products and references can be found at the end of this review. Around 400 abstracts from papers in the Polymer Library are included with an index. Subjects covered include tyre wear and failure, seals, engine components, rubber bonding failure, rubber failure due to chloramine in water, tank treads, gloves and condoms, medical devices and EPDM roofing membranes.
Annotation This report details the results of accelerated heat ageing studies undertaken on re-mixed samples of those materials studied for the natural ageing study and on the 20 new compounds chosen to represent polymers not available in 1958 and to reflect changes in compounding practice. In addition to those properties studied for the artificial weathering exposures compression set and dynamic properties were also measured.
Rubber is important in many engineering applications because of its unique properties. These properties must be measured with appropriate test methods developed specifically for this class of materials. This book provides, in one volume, comprehensive coverage of the procedures for measuring the whole range of the physical properties of rubber. This new edition presents an up-to-date introduction to the standard methods used for testing, quality control analysis, product evaluation, and production of design data for rubber and elastomers. Factors to be incorporated in the revision include the effects of newer instrumentation, the cutting back of laboratory staff, increased demands for formal accreditation and calibration, trend to product testing, overlap of thermoplastic elastomers with plastics and increased need for design data.
This title brings together a variety of papers presented at the 9th annual Meso meeting in 2007. The topics selected for Meso 2007 are designed to illustrate the relation of thresholds to multiscaling: Flow through capillary tubes in contrast to pipes Laminar and turbulent flow transition Heat convection of thin wires in contrast to cylinders Electrical conductance of macro- and nano-circuits Rubbery and glassy polymers Single- and poly-crystal behavior Strength of wires and round cylindrical bars Uni-axial and multi-axial material: linear and non-linear response Thin and thick plate behavior Brittle and ductile fracture Small and large crack growth behavior Low and high temperature effects Local and global material property characteristics Small and large bodies: size and time effects Specimen and structure
This book provides comprehensive coverage of all aspects of physical testing of elastomers (rubbers and thermoplastic elastomers) including mechanical, electrical, thermal and all aspects of durability. Elastomers are an important class of materials used in such products as tyres, seals and hose which have markedly different properties to other materials. The importance of testing of elastomers means that a comprehensive text on the subject is essential. The advantage over general materials testing books is being more specific while the advantage over general rubber technology books is that testing is dealt with in depth.
Featuring the work one of the world's foremost authorities on rubber curing, this uniquely comprehensive resource provides valuable data that will allow researchers and engineers to find solutions to their own curing problems. It delves into a variety of current evaluation practices for unvulcanized and vulcanized rubber and curing methods, i
This revolutionary and best-selling resource contains more than 200 pages of additional information and expanded discussions on zeolites, bitumen, conducting polymers, polymerization reactors, dendrites, self-assembling nanomaterials, atomic force microscopy, and polymer processing. This exceptional text offers extensive listings of laboratory exercises and demonstrations, web resources, and new applications for in-depth analysis of synthetic, natural, organometallic, and inorganic polymers. Special sections discuss human genome and protonics, recycling codes and solid waste, optical fibers, self-assembly, combinatorial chemistry, and smart and conductive materials.
This is an overview of the factors tyre compounders and engineers must consider when developing compounds for tyres. It discusses compounding ingredients for tyre rubbers by class including polymer types. The future of tyres in vehicles is also outlined. An additional indexed section containing several hundred abstracts from the Polymer Library provides useful references for further reading.
