Study of Cross-Linking Density and the Type of Cross Linkage in Polyurethane Elastomers (Sintez i Fiziko-Khimiya Poliuretanov),
FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OH
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From the standpoint of synthesizing cross-linked polymers with the potentially smallest degree of defectiveness of the network, polyurethane polymers are of special interest. The purpose of this work is to study the validity of theories that make it possible to evaluate the cross-linking density based on different physical methods for polyurethane elastomers. One of the main parameters that characterize the structure of cross-linked polymer is the value of the effective cross-linking density or the mean molecular weight of the chain segment between units. The kinetic theory of elasticity and the Flory-Renner theory of swelling are the basis for determining this value. In our study, we used the methods of evaluating the cross-linking density from data about the equilibrium modulus of high elasticity and about the compression of swollen specimens in order to determine the parameter Psi of the Flory equation, which would also make it possible to make these measurements based on data about swelling.
- Elastomers and Rubber