Abstract
The process of steric network formation in polymers is accompanied by the formation of branched macromolecules of varying degrees of complexity. Flory [1] suggested the theory of a broad degree of complexity existing in the molecular chain distribution The larger macromolecular complex-formed appear to become the centre around which the steric structure forms (micro-gel). The reaction system becomes structurally heterogeneous after a certain conversion is reached; it can be assumed that the system is then divisible into two phases (sol-gel) owing to micro-incompatibility i.e. that the system becomes micro-heterogeneous. The transition from a homogeneous to a micro-heterogeneous system must produce changes in the mechanism of network formation, and must be accompanied also by changes of its relaxation properties. We have studied the kinetics of the setting of polyurethane systems in combination with measurements of the vitrification parameters, to check the correctness of our assumption; this was done during the process of network formation.
Published Version
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