Rheological evidence for high-temperature phase transitions in melts of high-density polyethylene
نویسندگان
چکیده
Melts of commercial high-density polyethylene (M — w = 36–85 6 10) were subjected to the hydrodynamics of a Haake Rheocord blender at temperatures (T) spanning the normal processing range (190–2608C), far beyond the disappearance of solid crystals at about 1408C. Torque measurements revealed a peculiar dependence on T, including transitions at about 2088C and 2278C, and non-Arrhenius behavior above and below this range. Resemblances to liquid-crystal polymer phenomena are pointed out, and the impact on the melt processing industries is discussed.
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