THE FORMATION OF HIGHER-ORDER STRUCTURES OF 1,3 IS-O-INSIDE-BIS-O-(P-METHYLBENZYLIDENE)-D-SORBITOL IN PHYSICAL GELS OF MOLTEN POLYMERS AND ORGANIC-SOLVENTS/

Citation
T. Kobayashi et al., THE FORMATION OF HIGHER-ORDER STRUCTURES OF 1,3 IS-O-INSIDE-BIS-O-(P-METHYLBENZYLIDENE)-D-SORBITOL IN PHYSICAL GELS OF MOLTEN POLYMERS AND ORGANIC-SOLVENTS/, Kobunshi ronbunshu, 55(10), 1998, pp. 613-627
Citations number
35
Categorie Soggetti
Polymer Sciences
Journal title
ISSN journal
03862186
Volume
55
Issue
10
Year of publication
1998
Pages
613 - 627
Database
ISI
SICI code
0386-2186(1998)55:10<613:TFOHSO>2.0.ZU;2-3
Abstract
It was found that 1,3 :2,4-cis-O- inside-bis-O- (p-methyl benzylidene) -D-sorbitol (PDTS) is a gelling agent for a wide range of organic sol vents and molten polymers. Falling ball, dynamic viscoelasticity (DVE) , and small-angle X-ray scattering (SAXS) methods are useful for deter ming sol-gel phase transition temperatures (T-fg's) of these physical gels, The X-ray analysis and the theoretical computer calculation appl ying the MOPAC system explored one of the possible models of the fine structure for PDTS fibril crystal networks; unit cell for the PDTS cry stal is a hexagonal lattice, a = b=31.5 Angstrom, c=4.4 Angstrom, and gamma=120 degrees, and each lattice point is occupied with four sets o f pair of intermolecular hydrogen bonded PDTS molecules with dipole mo ments antiparallel each other along the c-axis. The self-assembly form ation of specific fibril crystals accompanied with sol-gel phase trans ition is based upon the relatively faster crystal growth along the c-a xis than perpendicular controlled by thermodynamical stability of poly meric interhydrogen bonding among PDTS molecules. According to the DVE analysis at a critical gel for the 2.5% PDTS/PS system, PDTS gel netw orks in mesoscopic range are characterized that they are mass fractal with d(f)= 2.4, in accordance with d(f)=2.3 +/-0.2 obtained from its s cattering profiles. The strengths of percolation networks made of 1.0, 1.25, and 2.5 wt% of PDTS are about 3.5 X 10(4), 4.3 X 10(5), and 1.0 X 10(6) Pa, respectively.