Durameter scales

Hardness of PTFE is determined by a mrmber of methods, such as ASTM D758 or D2240 (Rockwell R Scale), or by Durameter scales. The mrmbers reported are Rockwell R Scale of 58, Durameter A Scale of 98, and Durameter D Scale of 50-65.P" Figure 3.25 illustrates the variation of hardness of PTFE and nylon as a function of temperatures. Both plastics become softer with increasing temperature but, in all temperatures, nylon is harder than PTFE. 

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