British Rubber Producers Research Association

Bateman, Gee, Barnard, and others at the British Rubber Producers Research Association [6,7] developed a free radical chain reaction mechanism to explain the autoxidation of rubber which was later extended to other polymers and hydrocarbon compounds of technological importance [8,9]. Scheme 1 gives the main steps of the free radical chain reaction process involved in polymer oxidation and highlights the important role of hydroperoxides in the autoinitiation reaction, reaction lb and Ic. For most polymers, reaction le is rate determining and hence at normal oxygen pressures, the concentration of peroxyl radical (ROO ) is maximum and termination is favoured by reactions of ROO reactions If and Ig. 

Improvement in the processing and vulcanized qualities of a range of systems have been reported over the past decades. Modification of natural rubber, due to work in the British Rubber Producers Research Association, yields some of the most striking applications of microgel. A detailed study at the MV Lomonosov Institute of Fine Chemical Technology, in Moscow, on the effect of microgels on mechanical properties of cis-polyisoprene and butadiene-styrene rubbers extensively illustrates the properties of blends from latex combination of microgel and conventional or linear systems.(31)... 

The mechanisms of autooxidation reactions were elucidated through the landmark research carried out at the British Rubber Producers Research Association, where the kinetics of autooxidation of olefins were studied in the 1940 s and early 1950 s. Some of the key researchers engaged in that work were L. Bateman, J. L. Bolland, G. Gee, A. L. Morris, P. Ten Have, among others. They contributed enormously to our understanding of autooxidation reactions of organic materials. Re-reading their papers produces appreciation of their important work and emphasizes the debt we, in polymer stabilization work, owe them. That work established the following ... 

Over the years, much of the research on accelerated-sulfur vulcanization was done by using natural rubber as a model substrate. Natural rubber was the first elastomer and therefore the search for understanding of vulcanization originated with work on natural rubber. Even in recent years most of the work published on the study of vulcanization has been related to natural rubber. This was because of the tradition of doing research on natural rubber and because of the fact that the largest knowledge base to build upon was with respect to natural rubber. It should be mentioned that a large factor in the establishment of the tradition of research on the vulcanization of natural rubber was the British Rubber Producers Research Association or BRPRA (now called the Malaysian Rubber Producers Research Association or MRPRA). Of course, this institution is essentially devoted to natural rubber. 

In comparison with the developments in new rubbers that have occurred this century, developments concerned with the chemistry of the reactions of the already-formed rubbery polymers have been less immediately spectacular. It has already been pointed out that for about ISO years sulphur has been the dominant vulcanizing agent, almost exclusively used with diene rubbers. It must however be stressed that the efficiency with which the sulphur is used and the quality of the vulcanizates is today vastly superior. In part this is due to systematic semi-empirical studies which led to the development of a wide range of accelerators of vulcanization. It is also in part due to the excellent scientific studies undertaken by many chemists throughout the world but particularly by the Malaysian Rubber Producers Research Association (and its forerunners the Natural Rubber Producers Research Association and the British Rubber Producers Research Association). As a consequence of this work the mechanism of vulcanization and its control, at least in the major diene rubbers, is reasonably well understood. 

Bloomfield and his co-workers at the British Rubber Producers Research Association took particular care not to heat their products above vulcanization temperatures during the analysis stage of their experiments (to avoid additional reactions) and used elemental analysis rather than the somewhat unreliable methods for determining unsaturation then available. As a consequence they were able to show that with cyclohexene and sulphur the following overall reaction occurs ... 

During the quarter of a century following World War II chemists at the British Rubber Producers Research Association (subsequently renamed the Natural Rubber Producers Research Association and, later, the Malaysian Rubber Producers Research Association) developed this work and using a variety of techniques have largely established the nature of the accelerated sulphur vulcanization of natural rubber. Important contributions have also been made by smaller research teams, for example Scheele and co-workers in Germany, and Craig, Juve, Campbell, Coran and Wise, and others in the United States. These studies have shown, not only that there are a variety of chemical structures present in a vulcanized natural rubber... 

The early success of Backstrom s kinetic radical theory of autoxidation was soon to be matched by the more elaborate work of researchers at the British Rubber Producers Research Association (BRPRA) in the late 1940 s. According to the chain reaction theory developed at BRPRA, the process of autoxidation is described in terms of a complex set of elementary reaction steps (Scheme 1) during the stages of initiation, propagation and termination. These early pioneering studies and their contribution to our current understanding of autoxidation and antioxidants has been reviewed recently. ... 

In 1952, the British Rubber Producers Research Association (BRPRA) had reported a detail method of NR depolymerisation through mastication. The stages of the process are ... 

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