Rubber-based products

Continuous vulcanisation of rubber based products such as thin conveyor belting, flooring and similar can be achieved using a large rotating heated drum. Pressure is exerted to the product by means of a continuous stainless steel belt which presses the sheet to the surface of the drum. The belt is also heated from its reverse side to give optimum heat transfer to the vulcanising rubber. 

Waste and litter is not the only concern of the public about plastics. There is enough truth in public criticisms of the performance of many household plastics products to concern the polymer industries. It is perhaps significant that rubber-based products such as motor car tyres,... 

Figure 4.1 The concept of curing and reinforcement in rubber-based products.

In conclusion, rubber-based blends are promising materials that can be designed to fulfill the requirements necessary for various types of applications— from medical devices and biomedical applications, to packaging applications, military and aerospace applications, tire industry applications, and structural applications. The chapter also addresses a new trend in the field of rubber-based product development— recycling old parts into powders and incorporating them in different matrices. 

Rubber-based products permeate our lives, forming part of the many materials used for personal, domestic and industrial purposes. Rubber may be natural, synthetic or a mixture of the two. Since the vast majority of rubberized materials are unlabeled, it is difficult to determine whether a product contains natural or synthetic rubber. The overlap between rubber and plastic further complicates the matter, especially since plastics contain many of the same catalysts, stabilizers, antioxidants and pig-ments/dyes that are present in rubber products. Fregert (1981) listed a number of naphthylamines, substituted para-phenylenediamines, alkylphenols and hydroquinone derivatives, which are utilized in the manufacturing of both rubber and plastic. Although completely cured plastics are rare sensitizers, fully cured rubber products produce allergic reactions as the sensitizers in rubber can leach out or bloom over time. 

As mentioned above, one of the principal problems that can be encountered with these types of systems is when they are applied to waste diene-rubber-based products, such as waste tyres, as the high temperatures that are required to enable some of the chemical agents to react with the sulfur crosslinks (e.g., the diphenyl sulfides, which usually require temperatures of around 150 C or more) also leads to degradation (e.g., reversion and/or oxidation) of the rubber with a reduction in Mw and, hence, important physical properties such a tensile strength. 

In general the nitroso rubbers also suffer from a poor resistanee to ionising radiation, sensitivity to degradation by organie bases, highly toxic degradation products and an exceptionally high cost. The advent of the rubbers based on perfluorofmethyl vinyl ether) considered above and of the phosphonitrilic elastomers considered below would appear to put the commercial future of these materials in extreme doubt. 

Although natural quartz, cristobalite and opal are used as fillers, only synthetic products (fumed and precipitated silicas) find use as fillers in rubber base adhesives. 

An electric conductive rubber base containing carbon black is laminated with an electric conductive cover layer of phosphoric acid ester plasticizer and other ionic surfactants to prepare antistatic mats, where the covers have colors other than black. It is also reported that alkyl acid phosphates act as color stabilizer for rubber. Small amounts of phosphate esters are helpful in restoring reclaimed rubber to a workable viscosity [284,290]. Esters of phosphoric acid are used in the production of UV-stable and flame-retarded alkylbenzenesulfonate copolymer compositions containing aliphatic resins and showing a high-impact strength... 

Foam Rubber A product produced exclusively from a liquid base, e.g., latex. Latex foam has an interconnecting cell structure and is most commonly used for cushioning applications. 

The property of elastic recovery of rubbers allows them to be used for many products which are subjected to deformation, whether by tension or compression, and must not be destroyed by such forces. Abrasion and corrosion resistances are often the main properties in choosing an elastomer-based product over alternative products. In the mineral processing industry, abrasion often results from a... 

The production of polydimethylsiloxane elastomer relies heavily on the purity of the parent dimethyldichlorosilane, since impurities of other monomers noticeably impair the properties of the elastomer and rubbers based on it. Methyltrichlorosilane has the strongest negative effect when dimethyldichlorosilane with impurities of this monomer is subjected to hydrolytic condensation, linear oligodimethylsiloxane develops branched me-... 

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