Low-temperature relaxations in amorphous polyolefins |
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| Authors: | A. Hiltner E. Baer J. R. Martin J. K. Gillham |
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| Affiliation: | 1. Department of Macromolecular Science , Case Western Reserve University , Cleveland , Ohio , 44106;2. Polymer Materials Program Department of Chemical , Engineering Princeton University , Princeton , New Jersey , 08540;3. Textile Research Institute , Princeton , N.J.;4. Polymer Materials Program Department of Chemical , Engineering Princeton University , Princeton , New Jersey , 08540 |
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| Abstract: | The dynamic mechanical relaxation behavior (1cps) of two series of amorphous polyolefins, ─(CH2)mC(CH3)2─ and ─(CH2)mC(CH3)(CH2 CH3)─ where m = 1, 2, 3 was investigated from 4.2°K to the glass transition. Most of the polymers show a damping maximum or pleateau in the 40 to 50°K region. Various mechanisms which have been suggested for cryogenic relaxations in amorphous polymers are considered as they might relate to the polyolefins. Two secondary relaxation processes above 80°K are distinguished. A relaxation at about 160°K (β) in the second and third member of each series is associated with restricted backbone motion. This process requires a certain degree of chain flexibility since it is not observed in the first member of each series. A lower Temperature process (γ) is observed in each member of the second series and is attributed to motion of the ethyl side group. |
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| Keywords: | flame retardancy mechanical properties polylactide POSS synergistic effect thermal degradation |
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