Search

According to the Kamlet-Abraham-Taft (KAT) polarity parameters (α, β, π*), polymers and solvents can be categorized as hydrogen-bond (H-bond) acidic (α>β) or H-bond basic (α<β). Recently, we proposed a quantitative hydrogen bonding (QHB) analysis to predict the solubility of polymers in ionic liquids (ILs) using the product of ΔαΔβ<0 as an indicator, where Δα is the difference between the H-bond acidic parameters of the polymer and IL, and Δβ is the difference in their basicity, while the prerequisite of the "complementary" principle (i.e., that one component is H-bond acidic and the other is basic) is satisfied. Here, the applicability of QHB analysis was first confirmed by testing the solubilities of carefully chosen polymer/deep eutectic solvent (DES) pairs, as the DESs were eutectic mixtures dominated by hydrogen bonding interactions. Then, our attention focused on the solubility of cellulose in DESs. Our testing results as well as the typical published results were summarized, which indicate that the potential DESs for cellulose dissolution and regeneration must be of the H-bond basic type because the "complementary" principle should be satisfied as a prerequisite. However, the H-bond basic DESs investigated in this study do not show the superior solubility of cellulose that has been commonly observed for H-bond basic ILs, even if the criterion of ΔαΔβ<0 is satisfied for both DESs and ILs. Possible reasons for this discrepancy are given to understand the varying effectiveness in cellulose dissolution for H-bond basic DESs and ILs. [ABSTRACT FROM AUTHOR]

The master curves of a series of aliphatic polycarbonates (APCs) with different lengths of methylene segments in the repeat unit were obtained by dynamic rheological measurements. The plateau modulus and entanglement molecular weight were determined and cross-checked by different methods. Though having distinct difference in chemical structure of repeat units, both APCs and bisphenol-A polycarbonates have the similar entanglement weight and entanglement spacing. On the other side, the plateau modulus decreases with increasing the length of the side group of aliphatic polycarbonates with different side-chain lengths in the literature. The packing length model can explain the relationship between chain structure and entanglements. [ABSTRACT FROM AUTHOR]