SVIBOR - Project code: 1-07-067


Strossmayerov trg 4, HR - 10000 ZAGREB
tel.: +385 1 459 44 44, fax: +385 1 459 44 69


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Project code: 1-07-067


Main researcher: VEKSLI, ZORICA (51754)

Type of research: basic
Duration from: 01/01/91. to 12/31/93.

Papers on project (total): 41
Papers on project quoted in Current Contents: 18
Institution name: Institut "Ruđer Bošković", Zagreb (98)
Department/Institute: Department for experimental Physics
Address: P.O.Box 1016
City: 10000 - Zagreb, Croatia
Phone: 385 (01) 4561-11-11

Summary: The presented research is concerned with basic understanding of the relationship between polymer structure, morphology, phase composition and relaxation processes and the macroscopic behaviour. Magnetic resonance methods (NMR and ESR - spin probe methods) are utilised. The correlations between the spin probe dynamics in a model system in the slow motion region and the local organization of macromolecules, depending on the size and structure of a spin probe are established. The processes connected with the change of free volume within the general framework of amorphous polymers are studied (crosslinking, degradation, mechanical deformation). The morphology of elastomers and molecular parameters that can influence different morphology are elucidated from the change of free volume. Mixtures of natural rubber and polystyrene latexes are prepared and the influence of the size of polystyrene domains on mechanical properties is studied. The molecular aspects of the reuse of waste rubber is analysed. NMR-relaxation measurements are used to characterize the polymer-polymer miscibility, orientational dynamics of polymer segments in macroscopically oriented block-copolymers and structure and molecular dynamics of melamine resins.

Keywords: ESR - spin probe method, NMR, polymers, molecular dynamics, relaxation processes, free volume, matrix inhomogeneity

Research goals: The main research aim is to gain more understanding about the relaxation behavior of polymers and complex polymer systems depending on the chain structure, phase composition and morphology by using magnetic resonance methods. The technique of spin probe in the region of very slow molecular motion (correlation time longer than 1 microsecond; double modulation ESR) will be applied to analyze the correlation between the change of free volume and the local arranmgements of macromolecules in the glassy polymers. The model system will be used in order to determine temperature limits of the method depending on the structure and size of a probe. In the range of faster motion of a spin probe (correlation time shorter than 0.1 microsecond) the matrix inhomogeneity will be investigated from the distribution of rotational correlation times of a probe in elastomers. This study is concerned with the parameters which influence different morphology of rather similar polymer chain microstructures. The NMR methods will be used to explore phase behavior (or domain structure) and molecular dynamics in elastomers and polymer mixtures in order to understand structure - dynamics - property relationship.


  1. Name of institution: Institut Charles Sadron, C.N.R.S.
    Type of institution: State institute
    Type of cooperation: Joint publishing of scientific papers
    City: 67083 - Strasbourg, Francuska

  2. Name of institution: "Sava" Kranj, Razvojno tehnološki inštitut
    Type of institution: Economical/Production
    Type of cooperation: Joint publishing of scientific papers
    City: 64000 - Kranj, Slovenija

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Last update: 10/09/95