Elastomers published works

Almost all types of elastomers can be bonded to a large variety of substrates by the process known as vulcanization. The strength of similar bonds by adhesive bonding, or post-vulcanization (PV) bonding, as it is also called, was originally believed to be much weaker and less resistant to environmental exposure. Published work has demonstrated that this is not true, with some exceptions. The advantages of PV bonding are " ... 

Extensive reviews on short fibers-reinforced elastomers have been published by Goettler and Shen, ° and more recently by Rajeev. Table 7.11 is a list of selected published works on natural fiber-filled rubber composites, sorted by rubber type. Only vulcanizable rubbers were considered in preparing the table thermoplastic rubber and rubber-plastics blends were omitted. As can be seen most grades of conventional elastomers have been considered with quite a large variety of natural fibers. Natural Rubber, SBR, and EPDM compounds have received much attention, as expected with respect to their industrial importance. A bonding system is us in most cases, with resin types (i.e. resorcinol-formaldehyde, resorcinol-hexamethylenetetramine, sil-ica-resorcinol-hexamethylenetetramine) the most frequent ones. 

In spite of these important results, the two-network method has had little impact on the discussion of the role of chain entangling in cross-linked elastomers. It was therefore decided to make a more detailed examination of the method and to try to develop a simpler method which would require fewer assumptions. The present paper is a discussion of recently published and unpublished work. 

Before BASF investigated this product, Quirk and Hsieh [1], Yuki and coworkers [2,3] and Fischer [4] carried out investigations with this monomer. The first two used the anionic polymerization mechanism and Fischer tried to copolymerize this monomer using free radical polymerization. In the latter case the yields were very low. The use of S/DPE blocks in thermoplastic elastomers [5] has also been briefly described. Some of the work carried out at BASF has been published in a recent review article [6], Owing to the enhanced thermal properties of this copolymer in comparison with atactic polystyrene - the glass transition temperature increases up to 180 °C, depending... 

Published information on urethane polymerization detail largely concerns thermoset urethane elastomers systems.4 13 In particular, the work of Macosko et. al. is called to attention. The present paper supplements this literature with information on the full course of linear thermoplastic urethane elastomer formation conducted under random melt polymerization conditions in a slightly modified Brabender PlastiCorder reactor. Viscosity and temperature variations with time were continuously recorded and the effects of several relevant polymerization variables - temperature, composition, catalyst, stabilizer, macroglycol acid number, shortstop - are reported. The paper will also be seen to provide additional insight into the nature and behavior of thermoplastic polyurethane elastomers. 

The authors would like to extend their appreciation to Dr. A. L. Logothetls for the Invitation to prepare and present this paper at the Rubber Division Session of the Macromolecular Secretariat Symposium 1983, to Dow Corning Corporation for permission to write this paper, to the Fluids, Lubricants, and Elastomers Branch, Nonmetalllc Materials Division, Air Force Materials Laboratory for supporting the f1uorohydrocarbon alkyl spacer work In part under contract No. F33615-69-C-1301 and for permission to Include this work In this paper, and to their many colleagues who carried out the described work (some of which has not been previously published outside the patent literature). 

FTIR-EGA is useful for evaluation of the effects of additives on thermal stability, and conversely can be used to distinguish between similar materials. Chlorine-containing polymers may be readily identified from their hydrogen chloride evolution profiles. Differences in formulations of the same polymer can be detected in the same way. The hydrogen chloride evolution profiles from three samples of PVC compound are shown in fig 4. One of the samples is clearly different from the other two. Confirmatory evidence is usually provided by the profiles for water, carbon dioxide and hydrocarbons. The FTIR-EGA technique has been similarly useful for characterisation of elastomers, epoxy and acrylic adhesive systems, polyurethanes, and acrylic glazing materials. The published literature on thermal degradation has provided a rich base on which to work. 

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. 

Dariusz M. Biel inski, DSc, is a professor at the Institute of Polymer and Dye Technology at Lodz University of Technology, Lodz, Poland, and is also affiliated with the Division of Elastomers and Rubber Technology at the Institute for Engineering of Polymer Materials and Dyes in Piastow, Poland. He has published many scientific papers, books, and patents, and he is an editorial board member of several professional journals and has worked on many technical program committees. 

This chapter deals with materials used by the rubber industry to facilitate the processing of elastomers prior to the vulcanization stage. Much of the work discussed was derived from a number of examinations of specific materials carried out in the laboratories of the Malaysian Rubber Producers Research Association (MRPRA). There is a dearth of such information in a published form thus it is felt that a detailed discussion of the work undertaken would be beneficially published in a laboratory-style reporting form. 

This paper will discuss the relevance and the irrelevance of surface energetics to polymer friction and wear. This survey covers most of the important works published in the past and during this recent Symposium. Since basic principles related to polymer friction have been reviewed by Tabor, and by Savkoor, the scope of this discussion will be limited to pertinent friction mechanisms with emphasis on surface interactions. First will be a brief discussion of the following friction processes polymer sliding, elastomer sliding, lubricated polymer sliding, polymer rolling. 

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