AbstractThe dynamic mechanical properties of molded and cast polyacrylonitrile and copolymers have been measured by an automatic Rheovibron. The transitions are described for the amorphous, “paracrystalline,” and crystalline phases. Based upon a number of polymer theories of multiple phases in polymeric systems, the transitions have been assigned to specific polymer motions. Three transitions are defined for the alpha transition region. The mechanical response is compared to x‐ray diffraction and infrared to ascertain the transition assignments in decreasing order beginning with the highest temperature transition as (1) the main transition for the amorphous phase (T1), (2) dipole–dipole interaction which is related to the “paracrystalline phase” (T2), and (3) secondary transition for the amorphous
展开▼
