2000 Fiscal Year Final Research Report Summary
Thee-dimensional structural analysis and rheology on phase-separated structure of polymer blends
| Project/Area Number |
11305067
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| Research Category |
Grant-in-Aid for Scientific Research (A).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
高分子構造・物性(含繊維)
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| Research Institution | Kyoto Institute of Technology |
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Principal Investigator |
TAKAHASHI Masaoki Kyoto Institute of Technology, Department of Polymer Science and Engineering, Professor, 繊維学部, 教授 (50115870)
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| Co-Investigator(Kenkyū-buntansha) |
JINNAI Hiroshi Kyoto Institute of Technology, Department of Polymer Science and Engineering, Lecturer, 繊維学部, 講師 (20303935)
柴山 充弘 東京大学, 物性研究所, 教授 (00175390)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Polymer Blends / Laser Scanning Confocal Microscopy / Three-dimensional structural analysis / Rheology / (Phase-Separated) Morphology |
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| Research Abstract |
The following results were obtained :
(l) Observation and structural analysis of phase-separated structure of a polymer blend
Direct measurement of phase-separated structure of a polymer blend bicontinuous morphology was done by tuse of laser scanning confocal microscopy (LSCM). The phase-separated structure was obtained in three-dimension (3D). Time-evolution of interfacial curvatures and their distributions were experimentally obtained, from which two basic processes of reducing interfacial area were found to occur in the course of the phase-separation.
(2)Development of thinning algorithm
An algorithm to find out the connectivity of network structure was developed. It is based on the existing algorithm but is modified to offer reliable results by applying some improvements that include modification of thinning rules at edge planes, better treatment ofjunctions attaching to the edge planes, etc. Infinite periodic minimal surfaces (IPMS) were used to check the precision and reliability of
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the algorithm. Although a few improvements may be necessary, the algorithm gives reasonable agreement with the mathematical predictions.
(3) Application of 3D thinning algorithm to a phase-separated morphology of a polymer blend
The 3D thinning algorithm were further used to obtain geometrical and topological features of the bicontinuous phase-separated structure of a polymer blend. It is found that the phase-separated domain possess, for the most part, 3 branches at each junction. Interjunction distance showed maximum at a distance a little bit shorter than the periodicity of the phase-separated structure. The Euler characteristics, demonstrating complexity of the network, showed that the bicontinuous structure of the polymer blend is topologically equivalent to a sphere with 2 to 3 handles. The dynamical self-similarity has been confirmed from the time-evolution of the geometrical and topological parameters.
(4) Observation of deformation and shape recovery of a dispersed droplet phase
An apparatus was developed to apply large step strains and to observe the shape of a deformed droplet phase from two perpendicular directions. It was found that the droplet shape changes to reduce the interfacial area. Starting from a flat ellipsoid, the shape changes to a rodlike, a dumbbell, an ellipsoid of revolution and finally back to a sphere.
(5)Relationship between shape recovery and stress relaxation for a dispersed droplet phase
The deformation and shape recovery of dispersed phase and the stress contribution from the interface are investigated for a blend melt of polystyrene and polycarbonate. The affinely deformed droplets recover to the spherical shape with the maximum relaxation time depending on the strain magnitude. The process of this recovery corresponds very well with the plateau and terminal relaxation appeared in the relaxation modulus.
(6) Viscoelasticity of polymer blend melt with continuous structure
The dynamic viscoelasticity and stress relaxation behavior are investigated for a 50/50 blend melt of polystyrene and poly (methyl methacrylate) with the modulated structure due to melt blending. The frequency dependence of the storage modulus shows a power law, reflecting the bicontinuous nature of the blend. The stretching and contraction of the continuous structure with the constant orientation angle are observed under large step strains. Less
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