Abrasion resistance of polymers

Sadegzadeh, M. and Kettle, R. J., Abrasion resistance of polymer impregnated concrete. Concrete, 32-34, May (1987). 

Method rf test for abrasion resistance of polymer-modified mortar ... 

Ohama, Y., and Shiroishida, K., Abrasion Resistance of Polymer-Modified Mortars (in Japanese), Nihon-Kenchiku-Gakkai Tohoku-Shibu Kenkyu-Hokokushu, No. 38, pp. 63-66, (Nov. 1981)... 

These improvements in properties not only enhance the performance of polymers in current applications, but also open up totally new product areas, such as — in particular, for polymeric materials — in machinery components, where the inherent softness and poor abrasion resistance of polymers have been the major limiting factors. 

However, the final properties of the tire show some poiats of superiority over natural mbber, ie, iu higher abrasion resistance of cold SBR. Siace the polymer has a T of —45° C compared with the —72 " C of aatural mbber, it shows poorer low temperature properties. Also, siace the resdieace of SBR is only about 50%, compared to at least 70% for the aatural mbber, there is more heat budd-up with SBR. Ia fact, although it is eatirely possible to produce an ad-synthetic automobde tire, this is not the case for tmck tires because their greater mass leads to an unacceptable degree of heat budd-up (13). 

Insertion of flexible blocks into the stiff polymer chain of PAN ensures the possibility of raising the resistance of modified PAN fibres to multiple deformations and, especially, increases significantly the abrasive resistance of fibres made of block copolymers. 

Abrasive wear of polymers has two components material can be removed by the rasping action of a countersurface or it can be sheared off viscoelastically by a countersurface to which it adheres. The precise balance of mechanisms depends on the characteristics of the counterface and the conditions under which the abrasion takes place. Many polymers exhibit excellent wear resistance, which in combination with their low coefficients of friction suit them for applications where lubrication is either impossible or undesirable. We use wear resistant polymers in such diverse applications as bushings in business machines, pump seals, and replacement hip and knee joints. 

Figure 8.17 shows how we can test the mar resistance of polymers. In this test, we rain abrasive grit down on an angled polymer sample at a known rate for a given period of time. We compare samples that have undergone testing under identical conditions to prepare a comparative ranking of mar resistance. 

Most polybutadiene is used in tyre applications, and the majority of this use is in blends with other polymers, such as NR and SBR, where polybutadiene reduces heat build-up and improves the abrasion resistance of the blend. The friction on ice of winter tyres is also improved by using higher levels of polybutadiene in the tread blend. 

Abrasion-resistance of transparent plastics still cannot equal that of glass. We have ways of improving or coating the polymer, but customers keep telling the industry that there is still a long way to go. 

Abrasion resistance is usually measured by the Taber Test procedure described by ASTM D1044. Abrasion resistance of unfilled semicrystalline polymers is linked to the degree of crystallinity that is itself related to the molecular stmcture and weight of the resin and its processing. Table 3.54 includes the results of testing two types of perfluoroalkoxy polymers, PFA and MFA, and ECTFE. Notice the large difference between wear index (weight loss by abrasion in 1000 cycles) of ECTFE which is a partially... 

Many thermoplastic polymers are reinforced with fibers. Reinforcement is nsed to improve physical properties— specifically heat deflection temperature. Glass fibers are the most commonly used reinforcing material. The wear resistance and abrasion resistance of the thermoplastics pol)nners are improved by the use of aramid reinforcing. Although fibers can be used with any thermoplastics polymer, the following are the most important ... 

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