Rubber heat resistance tests

ISO 188, Rubber, vulcanized or thermoplastic - Accelerated ageing and heat resistance tests (available in English only), 1998. 

ISO 188 1998 Rubber, vulcanised—Accelerated ageing or heat resistance tests. 

ISO 188 2011 Rubber, Vulcanized or Thermoplastic. Accelerated Ageing and Heat Resistance Tests. 

Neoprene is the generic name for polychloroprene rubber. It has been produced commercially since 1931 and had rapid and wide acceptance because it is much superior to natural rubber for heat and oil resistance. Heat resistance is far better than NR, BR or SBR. but less than EPDM. When heated in the absence of air, neoprene withstands degradation better than other elastomers which are normally considered more heat resistant, and retains its properties fifteen times longer than in the presence of air. Compression set at higher temperature is better than natural rubber and 100°C is typically the test temperature rather than 70°C. Abrasion resistance is not as good as natural rubber but generally better than most heat resistant and oil resistant rubbers. This is also true for tear strength and flex resistance. 

Even before the discovery of vulcanisation by Goodyear [1], the effects on rubber of heat, light, acids and alkalies were studied. Testing became necessary when early investigators faced problems with rubber and its vulcanisates. Possibly the earliest chemical resistance test on rubber was undertaken by Goodyear when he treated rubber with nitric acid and this yielded a hardened mass [2, 3]. He mistakenly called this phenomenon vulcanisation, before he accidentally discovered vulcanisation with sulfur at a later point. 

Tests for elastomer resistance to air have to be considerably accelerated in the laboratory by exposure to pure oxygen (pressure test, 21 bar, 70°C) or in the ozone test chamber (standard pressure, 50-200 ppm ozone, 25°C, s. Section 2.2.8). While oxygen influence is rated as a percentage loss of properties, comparable to heat aging tests in air, ozone influence is evaluated according to crack formation in the rubber transverse to the tensile or bending direction (evaluation levels 0 to 3) [229]. 

Matsushita Electric Industries Co. Ltd have described in patents [28] the use of a porous heat-resistant layer to provide increased abuse tolerance to hthium-ion cells. In particular, the presence of a heat-resistant layer provides improved performance in nail penetration tests. In one example, a heat resistant layer consisting of alumina particles and a polyacrylonitrile rubber binder is coated onto both sides of the negative electrode and used with a conventional separator. In one embodiment, the separator is not used, and instead the separation is provided entirely by the coating on the negative electrode. According to one patent disclosure [29], the battery does not need a conventional expensive separator sheet, thereby making the production cost low, which holds great industrial promise. ... 

HAF (high-abrasion furnace black) highly reinforcing furnace carbon black increasing resistance of a rubber compound to abrasion, heat aging exposure of polymeric materials under specified conditions (temperature, time, presence or absence of air or oxygen, etc.) then testing them... 

Apart from being simply measures of how much a rubber creeps, relaxes or sets under any given conditions, these tests can also be used as measures of ageing characteristics, low temperature resistance or resistance to chemicals. These other applications of the tests are not generally considered in this chapter but it is impossible to make a complete distinction. In particular, set tests commonly used as a quality control tool involve heat... 

For each specific application of a rubber compound as an insulating material, there is a minimum value of resistivity below which it does not function satisfactorily. In addition, insulating compounds are required to withstand the effect of water, moist atmosphere, or heat without their resistivity values falling below a satisfactory level. Insulation resistance measurements frequently serve as useful control tests to detect impurities and manufacturing defects in rubber products. 

Introduce 5 drops of the 0.1 M solutions to be tested into each of five test tubes carrying some form of serial numbers resistant to heat and water (rubber bands), and prepare a beaker of hot water in which all the tubes can be heated at once. Measure 2.5 mLofFehling ssolutionlintoa 10-mLflask... 

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