Page 262 - Engineering Plastics Handbook
P. 262

224   Engineering Plastics

        ■ The effect of the amino-substituted position of the etherdiamine
        ■ Number of benzene rings in ether diamine (Table 10.2)
        ■ Amino substituted position in ether diamine
        ■ Optimum molecular weight

        These factors affect the thermoplasticity of polyimides. Then it was con-
        cluded that

        1. Thermoplasticity can be controlled through the selection of ether
           diamine with a specific chain length.
        2. Polyimide from meta amino substituted diamine has less heat resist-
           ance than polyimide from the para form. The polymer of the meta
           form, however, has much better plasticity than that of the para form,
                       and T .
           in light of T g  m
               ®
        Aurum has a chemical structure consisting of repeating units of
        pyromellitic dianhydride and 4,4′-bis(3-aminophenoxy)biphenyl, with T g
        = 482°F (250°C) and T = 734°F (390°C).
                             m

        Products and Design

        Applications Using Mitsui Chemicals
              ®
        Aurum TPI
        There are five major categories for the applications:
        1. Electronics, electrical, and semiconductor
        2. Automotive
        3. Industrial (including business machinery)
        4. Wire, cable, film, and fiber
        5. Aircraft and aerospace

        The heat resistance has helped applications in various parts that need
        high-temperature resistance, up to 455°F (235°C).
          Moreover, the dimensional stability based on high heat resistance
        has increased applications requiring tight tolerances of the parts. The
        superior wear and friction properties of polyimide have fascinated many
        engineers who had to design parts used under harsh conditions. This is
                                                         ®
        so because many kinds of parts made with Aurum have been com-
        mercialized.

        Electronics, electrical, and semiconductor. The excellent dielectric prop-
        erties and resistance to heat and abrasion that characterize Aurum ®
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