INVESTIGATION OF POLYMERS BY MAGNETIC RESONANCE METHODS
Main researcher
: VEKSLI, ZORICA (51754) Assistants
VALIĆ, SREĆKO (135761)
RAKVIN, BORIS (40206)
ANDREIS, MLADEN (485)
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
Communication
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.
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.
COOPERATION - INSTITUTIONS
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
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 Other information about the project.