TY - JOUR
T1 - Microstructure and nematic transition in thermotropic liquid crystalline fibers and their single polymer composites
AU - Kalfon-Cohen, Estelle
AU - Marom, Gad
AU - Weinberg, Amotz
AU - Wachtel, Ellen
AU - Migliaresi, Claudio
AU - Pegoretti, Alessandro
PY - 2007/9
Y1 - 2007/9
N2 - We describe a new single polymer composite (SPC) prepared from two liquid crystalline vectran fibers. Vectran M is the as-spun fiber while vectran HS is the high-strength version. A study of the morphology of the pristine materials shows that the two fibers have different crystal structures. The wide-angle X-ray diffraction (WAXD) data confirm the presence of the so-called pseudo-hexagonal (PH) unit cell in vectran M, while an orthorhombic structure is revealed in the vectran HS fibers. A transition to the nematic phase is observed by in situ X-ray diffraction at ∼277°C for the M fibers and at ∼315°C for the HS fibers. During the compaction process, the orientation of the reinforcing fibers is well maintained and the transition to a nematic phase seems to be delayed by processing at high applied pressure. Concomitantly, vectran M loses its orientation and the transition to the nematic phase disappears.
AB - We describe a new single polymer composite (SPC) prepared from two liquid crystalline vectran fibers. Vectran M is the as-spun fiber while vectran HS is the high-strength version. A study of the morphology of the pristine materials shows that the two fibers have different crystal structures. The wide-angle X-ray diffraction (WAXD) data confirm the presence of the so-called pseudo-hexagonal (PH) unit cell in vectran M, while an orthorhombic structure is revealed in the vectran HS fibers. A transition to the nematic phase is observed by in situ X-ray diffraction at ∼277°C for the M fibers and at ∼315°C for the HS fibers. During the compaction process, the orientation of the reinforcing fibers is well maintained and the transition to a nematic phase seems to be delayed by processing at high applied pressure. Concomitantly, vectran M loses its orientation and the transition to the nematic phase disappears.
KW - Liquid crystalline polymer
KW - Nematic transition
KW - Single polymer composite
KW - WAXD
UR - http://www.scopus.com/inward/record.url?scp=34648831512&partnerID=8YFLogxK
U2 - 10.1002/pat.934
DO - 10.1002/pat.934
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
AN - SCOPUS:34648831512
SN - 1042-7147
VL - 18
SP - 771
EP - 779
JO - Polymers for Advanced Technologies
JF - Polymers for Advanced Technologies
IS - 9
ER -