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Vulcanized rubber, property

Aromatic hydrocarbon, halogen hydrocarbon General characteristics At room temperature, the polymer shows vulcanized rubber properties and exhibits thermoplasticity at elevated temperatures. It shows resin properties following increase in styrene concentration. When using trans-polybutadiene, it shows a shape memory tendency. It is possible to process while melted and is strong and has high-elasticity and good low-temperature characteristics. It also has exceptional acid resistance and alkali resistance. [Pg.1551]

Improvement in the solvent and oil resistance of rubbers can be achieved via grafting of acrylonitrile onto rubber [140-142] and rubber blends [143]. The careful control of the degree of grafting allows vulcanized rubber with high-mechanical properties compared with ungrafted vulcanized rubber to be obtained. Also, acid resistance [144] and resistance to microbiological attack [145,146] was improved for cellulose grafted with acrylonitrile, and increases in base resistance were also noted for MMA and a mixture of MMA and ethyl acrylate [13],... [Pg.512]

Thermoplastic elastomers are materials that have the properties of vulcanized rubbers but can be processed by techniques associated with thermoplastics. The commercial importance of TPEs is due to their superior processing properties and economic advantages over conventional rubbers and plastics. TPEs from rubber-plastic blends became important because they combine the superior processability of thermoplastics and the... [Pg.647]

Ionic polymers are a special class of polymeric materials having a hydrocarbon backbone containing pendant acid groups. These are then neutralized partially or fully to form salts. lonomeric TPEs are a class of ionic polymers in which properties of vulcanized rubber are combined with the ease of processing of thermoplastics. These polymers contain up to 10 mol% of ionic group. These ionomeric TPEs are typically prepared by copolymerization of a functionalized monomer with an olefinic unsamrated monomer or direct functionalization of a preformed polymer [68-71]. The methods of preparation of various ionomeric TPEs are discussed below. [Pg.115]

In 1839, Charles Goodyear discovered that sulfur could cross-link polymer chains and patented the process in 1844 [1]. Since then rubber became a widely usable material. By the year 1853, natural rubber (NR) was in short supply. So attempts were made to undo what Goodyear had accomplished. Goodyear himself was involved in trying to reclaim vulcanized rubber to overcome the shortage of NR. Later, as a consequence of World War I, Germany introduced synthetic rubbers, namely the Buna rubbers, which raised the curiosity of polymer chemists all over the world. Subsequently, synthetic rubbers with tailor-made properties were born. This was followed by the discovery of new methods and chemicals for vulcanization and processing. It is obvious... [Pg.1043]

Lord Kelvin s close associate, the expert experimentalist J. P. Joule, set about to test the former s theoretical relationship and in 1859 published an extensive paper on the thermoelastic properties of various solids—metals, woods of different kinds, and, most prominent of all, natural rubber. In the half century between Gough and Joule not only was a suitable theoretical formula made available through establishment of the second law of thermodynamics, but as a result of the discovery of vulcanization (Goodyear, 1839) Joule had at his disposal a more perfectly elastic substance, vulcanized rubber, and most of his experiments were carried out on samples which had been vulcanized. He confirmed Gough s first two observations but contested the third. On stretching vulcanized rubber to twice its initial length. Joule ob-... [Pg.436]

A small amount of the bis-azo compound—sufficient to react with only 1 or 2 percent of the isoprene units—converts the specimen to a material having all of the physical properties characteristic of vulcanized rubber. Polychloroprene may be vulcanized by the action of metal oxides... [Pg.457]

Despite of 150-year s history of vulcanization process, it is impossible to consider that fundamental and applied researches in direction of vulcanization systems perfection are completed. For today one of the ways of rubbers properties improvement is the synthesis and application of the new chemicals-additives, including, vulcanization active, that is connected, first of all, with reduction of global stocks of zinc ores as basic raw material for reception of traditional activator - zinc oxide. Besides, modem increase of industrial potential and the accumulation of big quantity wastes derivate the problems of ecological character, which require the emergency decision. Therefore creation of resourcesaving technologies of the new compounds reception from products of secondary raw material processing has paramount importance. [Pg.190]

Classifying polymers in their crosslinked state according to end-use properties, polymer networks include vulcanized rubbers, crosslinked thermosetting materials, protective coatings, adhesives, polymeric sorbents, microelectronics materials, soft gels, etc. Polymer networks in contrast to uncrosslinked polymers,... [Pg.113]

DuPont was looking for a synthetic rubber (SR). Carothers assigned Arnold Collins to carry out this research. Collin s initial task was to produce pure divinylacetylene. While performing the distillation of an acetylene reaction, in 1930, he obtained a small amount of an unknown liquid, which he set aside in a test tube. After several days the liquid turned to a solid. The solid bounced and eventually was shown to be a SR polychloroprene, whose properties were similar to those of vulcanized rubber but was superior in its resistance to ozone, ordinary oxidation, and most organic liquids. It was sold under its generic name neoprene and the trade name Duprene. ... [Pg.745]

By the process of vulcanization, rubber elasticity, impact resistance, flexibility, thermal stability and many other properties are either introduced or improved. In addition, the crosslinking of non-elastomeric polymers increases the toughness, abrasion resistance and, particularly, the maximum service temperatures of the material. [Pg.141]

Flory,P.J. Network structure and the elastic properties of vulcanized rubber. Chem. Rev. 35, 51-75 (1944). [Pg.164]

Property Requirements of Vulcanized Rubber 2.6.1 Stress-strain Properties... [Pg.12]

Reversion - The softening of vulcanized rubber when it is heated too long or exposed to elevated temperatures. It is a deterioration in physical properties, (extreme reversion may result in tackiness.) This most commonly affects natural rubber linings. [Pg.270]

The importance of crosslinked polymers, since the discovery of cured phenolic formaldehyde resins and vulcanized rubber, has significantly grown. Simultaneously, the understanding of the mechanism of network formation, the chemical structure of crosslinked systems and the motional properties at the molecular level, which are responsible for the macroscopic physical and mechanical properties, did not accompany the rapid growth of their commercial production. The insolubility of polymer networks made impossible the structural analysis by NMR techniques, although some studies had been made on the swollen crosslinked polymers. [Pg.8]

F10. —, N. Rabjohn, and M. C. Shaffer Dependence of elastic properties of vulcanized rubber on the degree of cross-linking. J. Polymer Sci. 4, 225... [Pg.229]

Substitute for Conventional Vulcanized Rubbers, For this application, the products are processed by techniques and equipment developed for conventional thermoplastics, ie, injection molding, extrusion, etc. The S—B—S and S—EB—S polymers are preferred (small amounts of S—EP—S are also used). To obtain a satisfactory balance of properties, they must be compounded with oils, fillers, or other polymers compounding reduces costs. Compounding ingredients and their effects on properties are given in Table 8. Oils with high aromatic content should be avoided because they plasticize the polystyrene domains. Polystyrene is often used as an ingredient in S—B—S-based compounds it makes the products harder and improves their processibility. In S—EB—S-based compounds, crystalline polyolefins such as polypropylene and polyethylene are preferred. Some work has been reported on blends of liquid polysiloxanes with S—EB—S block copolymers. The products are primarily intended for medical and pharmaceutical-type applications and hardnesses as low as 5 on the Shore A scale have been reported (53). [Pg.17]

Effects on physical properties of vulcanized rubber were analyzed in a research lab. Based on research results the influence of three factors on the strength of vulcanized rubber was tested ... [Pg.106]


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