27/07/11
Cao su Việt xin giới thiệu đến các bạn một quyển sách nói về thời gian sống hữu ích của cao su, có thể hữu ích với người đang theo nghề cao su...đây là quyển sách có bản quyền, được sưu tầm tại trang chemtec.org.
Sau đây là tóm tắc nội dung:
Practical Guide to the Assessment of the Useful Life of Rubbers
After price and delivery time, the most frequently asked question about a product is 'How long will it last?' This is usually a very difficult question to answer for rubber products because the expected lifetime is often in tens of years, the service conditions may be complex, and there is a scarcity of definitive data on durability. There is a vast matrix of degradation agents, service conditions, properties of importance and different rubbers.
There are also many inherent difficulties in designing tests. In many cases, the timescale 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 lifetime of rubbers are made by considering some measure of performance, such as tensile 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 number of cycles of use.
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. The Guide aims to make available the wealth of information that can be applied to help maximize the effectiveness of a durability testing program.
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 textbooks and International standards are referenced.
Rapra Technology Limited has just completed a 40 year natural ageing program and an accelerated testing program, both on the same set of rubber compounds. The results have been drawn on in this Guide to indicate the limiting factors for particular test methods.
This publication is an output from the Weathering of Elastomers and Sealants project which forms part of the UK government's Department of Trade and Industry's Degradation of Materials in Aggressive Environments Program.
This book will be useful for anyone responsible for designing, manufacturing or testing rubber 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.
