Interaction energies between relatively rigid benzobisoxazole and benzobisthiazole polymers were calculated in an attempt to gain insight into the very high mechanical strength and unusual solvent resistance of these materials. The predicted details of the chain packing and the corresponding densities were found to be in good agreement with experimental results obtained on relevant model compounds in the crystalline state. The interaction energies are estimated to be very large, with van der Waals contributions being far more important than Coulombic ones. Additional calculations indicate that protonation of the chains should greatly decrease the intermolecular attractions, even at very high dielectric constant. This conclusion is consistent with the fact that only extraordinarily strong acids are solvents for these types of chain molecules.
All Science Journal Classification (ASJC) codes
- Organic Chemistry
- Polymers and Plastics
- Inorganic Chemistry
- Materials Chemistry