Micro theoretical study on the compatibility and mechanical properties of polyacrylamide/polyvinyl alcohol blends

The theoretical method of molecular dynamics was applied to study the PAM/PVA blends at the level of microscopic molecular interaction. The interaction mechanism and nature of PAM/PVA blends are elaborated from the aspects of the compatibility, binding energy and the correlation function analysis, respectively. We have analyzed the static mechanics of system with different quality components, and studied the effects of different quality components on the mechanical properties of system. Results show that the compatibility between PAM and PVA was very good, and the binding energy between the single component of system is decreased with the increase of PVA content, the main reason is that the number of polar functional groups contained in a PAM chain was higher than the same quality PVA chain. In addition, the analysis of the correlation function shows that the single component interacts with each other mainly by hydrogen bonds, and the possibility relationship of the hydrogen bond which formed between the amine groups (-NH₂), carbonyl groups (-C=O), hydroxyl groups (-OH) and the hydrogen atoms around them was O_(-C=O)=O_(-OH)=N_(-NH2). This was a reflection of the polarity relationship among the amide groups, carbonyl groups and hydroxyl groups. The static mechanical results of models with different component quality ratio show that, with the increase of PVA content, the elastic coefficient, the various engineering modulus and cauchy pressure value are all increased, namely the increase of PVA content can significantly improve the mechanical properties and ductility of PAM.