Microscopic and macroscopic modelling of polymerization shrinkage.

During polymerization of monomers into polymer chains a reduction in volume is observed. Shrinkage may cause internal stresses and strains of a final product. It makes some difficulties in technical applications of polymers, especially in dentistry and stereolithography. In the presented paper, two ways of modelling and descriptions of the polymerization shrinkage will be described: the molecular approach based on chemical analysis, and the phenomenological approach based on investigation of density changes in polymer-monomer system. Because the polymerization is time dependent process, the rate of reaction and the course of reaction are important issues. The influence of viscosity and vitrification on the rate of polymerization and finally on the polymerization shrinkage will be described. [ABSTRACT FROM AUTHOR]