Mechanical Spectroscopy of Side Chain Liquid Crystalline Polymers
we report a low frequency mechanical relaxation study of molecular motions near and below glass transition in side chain liquid crystal polymers (SCLCP) in the cholesteric state. The SCLCP was a blend of crosslinked and uncrosslinked materials. Different compositions were studied. These materials exhibit low temperature relaxation processes and a main relaxation connected to the glass transition. Localiscd motions arc responsible for the low temperature processes while the main relaxation exhibits cooperative features and is sensitive to the amount of crosslinked fraction. The relaxation blue in the glass transition range when plotted against normalised reciprocal temperature shows that the molecular motions display a fragile character in agreement with the highly cooperative feature and strong physical aging effects. These observations are discussed in the frame of correlated motions involved in the liquid glass transition.
The aqueous two-phase system has been applied to the separation of biomolecules because of its gentle character, easy operation and high separating efficiency. The systems that are being used may include the poly-poly system, the poly-electrolyte system and the newly-developed micellar system. In this paper, we analyzed the thermodynamic models for the partition-calculating coefficients of protein in each system, hoping that is will be of help for further research.