1989 Fiscal Year Final Research Report Summary
Study on the phase transition and molecular motion of polyphosphazenes
| Project/Area Number |
62550649
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
高分子物性
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| Research Institution | Gifu University |
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Principal Investigator |
MORIYA Keiichi Gifu University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (40174461)
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| Co-Investigator(Kenkyū-buntansha) |
YANO Shinichi Gifu University, Faculty of Engineering, Professor, 工学部, 教授 (70021607)
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| Project Period (FY) |
1987 – 1989
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| Keywords | Polyphosphazene / Inorganic Polymer / Dielectric Measurements / Liquid Crystalline Polymer / Mesomorphism / Molecular Motion / Polymer Synthesis / 液晶組織 |
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| Research Abstract |
1. Polyphospbazenes with phenoxy and benzyloxy derivatives in the pendant groups were synthesized and studied the phase transition and molecular motion by DSC and dielectric measurements. In the polyphosphazenes with phenoxy derivative pendant groups beta relaxation and gamma relaxation were observed above and below the glass transition in the dielectric measurements. beta relaxation was considered to be due to the microbrownian notion of tie main chain and gamma' one due to uptake water. In the polyphosphazenes with benzyloxy pendant groups beta refixation and gamma relaxations were observed. gamma relaxations are considered to be local motion of side chain.
2. Synthesis of polyphosphazenes with -SC_6H_5 pendant groups was tried but only 85 % of side chain was replaced.
3. Polyfluoroalkoxyphosphazenes with pendant groups of -OCH_2CF_3, -CH_2(CF_2)_nCF_2H(n=2.4,6) and -CH_2(CF_3)_2 were synthesized and studied the phase transition and molecular motion by dielectric and DSC measurements.
… More
In the polymers with pendant groups of -OCH_2CF_2CF_3 and -OCH_2(CF_2)_6CF_2H(PHDFHP), phase transitions were found at 233 K(DELTAS=13.5 JK^<-1> g^<-1>) and 260 K(DELTAS=7.2 JK^<-1> g^<-1>), respectively. The jumps of the dielectric constant at these temperatures and large phase transition entropies show that the phase transition has the characteristics of first order and the high temperature phases are highly disordered. In PHDFHP the alpha relaxation (DELTAH=105 kJmol^<-1>) was observed. In the polyphosphazenes with the pendant hydrofluoroalkoxy groups the activation enthalpy of the beta relaxation is lower than those of perfluoroalkoxy side groups.
4. Polyfluoroalkoxyphosphazene with cholesterol pendant groups was tried but only 3 % cholesterol was introduced into the side chains.
5. Polyphosphazenes with 4-cyano biphenyl pendant groups are synthesized and studied the mesogenicity by DSC and polarizing microscope observation but the liquid crystalline state was not found. However, in hexakis[4-(4- cyano)biphenoxy] cyclotriphosphazene which is a precursor of polymer, the monotropic nematic phase was found between 529 and 488 K.
6. Synthesis of polyphosphazenes with a 4-decyloxybiphenoxy pendant groups was tried but is not succeeded up to now. But in its precursor, hexakis[4- (4-decyloxy)biphenoxy] cyclotriphosphazenes, the Smectic C was found by the DSC measurements and polarizing microscope observation.
7. Synthesis of polyphosphazenes with alpha-D-glucose was tried but only 5 % in side chain was replaced by the glucose. Less
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Research Products
(10 results)
