Natural rubber opportunities

Wherever possible, the soaps and surfactants were added to the natural rubber latex as dilute aqueous solutions. The cases where this was not possible were (a) ethylene oxide-fatty alcohol condensates of low ethylene oxide fatty alcohol mole ratio, and (b) sparingly-soluble fatty-acid soaps such as lithium laurate and calcium soaps. The former were added as pastes with water, the latter as dry powders. In all cases, the latex samples were allowed to mature for about three days at room temperature before their mechanical stabilities were determined. This allowed some opportunity for the attainment of adsorption equilibrium. 

As already said in the Preface, a question arose as to the appropriateness of having a chapter in this book devoted to the cure of rubbers and to their properties concerned with the recovery of scrap rubber obtained from old tires. However, the amount of old tire rubber is so large that it could be considered as a raw material, and reclaiming will become a necessity when crude oil and natural rubber experience shortages. This problem is so vast that only a book in itself could describe all the possibilities of reusing. Nevertheless, a large number of opportunities has been identified, and the reclaiming processes based on the cure of these scrap rubbers have been considered. 

Natural Rubber-Based Composites and Nanocomposites State of the Art, New Challenges and Opportunities... 

Our own experience, as well as that of other authors, has shown that very precise measurement for the stress-strain relationship under general biaxial deformation is required to investigate the behavior of the strain energy density function of rubber vulcanizates. Unfortunately, available biaxial extension data are still too meager to deduce the general form of the strain energy density function of rubber-like substances. We wish to take this opportunity to summarize the principal results from our recent efforts, in the hope that they may serve to illustrate the interesting and complex nature of the derivatives 31V/9/,- of such substances. 

NR is one of the world s important natural resources and sihca is considered environmentahy friendly upon disposal. Thus, in terms of sustainability development, development of sihca-fihed NR nanocomposites opens new opportunities for producing green materials/products such as tyres. Traditionally, carbon black is preferred over sihca as fiber in tyres due to the challenge in dispersing sihca in rubber compounds. With the new development, e.g. in situ sol gel silica, admicellar polymerization and polymer-encapsulated sihca, the applications of nano-silica in NR and modified NRs are widened. 

Table 2.5 summarises the main applications of thermal analysis and combined techniques for polymeric materials. Of these, thermomechanical analysis (TMA) and dynamic mechanical analysis (DMA) provide only physical properties of a very specific nature and yield very little chemical information. DMA was used to study the interaction of fillers with rubber host systems [40]. Thermomechanical analysis (TMA) measures the dimensional changes of a sample as a function of temperature. Relevant applications are reported for on-line TMA-MS cfr. Chp. 2.1.5) uTMA offers opportunities cfr. Chp. 2.1.6.1). The primary TA techniques for certifying product quality are DSC and TG (Table 2.6). Specific tests for which these techniques are used in quality testing vary depending upon the type of material and industry. Applications of modulated temperature programme are (i) study of kinetics (ii) AC calorimetry (Hi) separation of sample responses (in conjunction with deconvolution algorithms) and (iv) microthermal analysis.

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