1. D AY 32: N AME THAT P OLYMER ! The following pages contain images of polymers as they are used in various applications. Each page is about a separate polymer, which appears in all of the applications on that page. It’s possible that 2 different pages might be showing the same polymer. We will form groups, and each group will be given about 2-3 minutes to discuss the polymer shown and try to identify it. Put your best guess and second best guess on the form. Points will be awarded 2 for best guess completely right, 1 for best guess partially correct or second guess completely correct.

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3. Material The most common plastic materials used for making gears are acetal, polybutylene terepthalate (PBT), nylon, polyphenylene sulfide (PPS), and liquid crystal polymer (LCP). Acetal is the most important of all plastics. It offers long term dimensional stability and excellent lubricity. It is often used in gears for office equipment, irrigation equipment, autos, appliances, clocks and meters PBT produces extremely smooth surfaces in molding and is often used in housing. Nylon offers toughness and wears well against other plastics. They are often used in worm gears and housings. PPS offers high stiffness, dimensional stability and extended fatigue life. fatigue LPC works well in small, precision gears under light loads, such as watch gears.

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