Comparative study on water structures in polyHEMA and polyMEA by XRD‐DSC simultaneous measurement

Abstract

ABSTRACT:We have found that poly(2-methoxyethylacrylate) (polyMEA) has excellent blood compatibility and proposed that the property is due to freezing bound water in the polymer. This water is defined as that which coldcrystallizes at around À45 C in the heating process of differential scanning calorimetry (DSC). In addition, we have already reported that the water in polyMEA is classified into three types, nonfreezing, freezing bound, and free waters, whereas the water in other polymers is just classified into two types: free and nonfreezing waters. (J Biomed Mater Res 68A, 2004, 684) However, the phenomenon observed by DSC is the enthalpy change and is not a direct evidence for crystallization. To confirm coldcrystallization, a comparative investigation of the thermal and crystallographical properties of water in hydrated polyMEA and poly(2-hydroxyethylmethacrylate) (polyHEMA) as a control was carried out using simultaneous measurements by X-ray diffractometer (XRD) and DSC. In addition, the effect of the water content in the polymers on the properties was studied. As for polyMEA, the finding that XRD crystalline peaks appearing in the heating process were assigned to hexagonal ice indicated cold-crystallization. On the other hand, in the case of polyHEMA, the crystal due to ice was formed only in the cooling process, and during the heating process, the growth of crystal ice was not observed.

DSC and TMA studies on freezing and thawing gelation of galactomannan polysaccharide

“…Both freezing bound water and non-freezing water were categorized as bound water. The results obtained in this study indicated the presence of freezing bound water in LBG hydrogels [21,22]. Micrographs ( Figure 6) also showed that quenched gel had small pore whose cell wall was thin.…”

Structural Changes of Gluten/Glycerol Plastics under Dry and Moist Conditions and during Tensile Tests

“…44,45 In this case, the dwater position was close to reported intermolecular distances of water clusters in water containing polymeric materials. [46][47][48] Furthermore, in our samples, there is a large amount of glycerol besides the AH and urea. Glycerol also interacts with water and the glycerol-water mixture may show different X-ray diffraction peak position depending on the concentration.…”

The Relationship Between Water Structure and Blood Compatibility in Poly(2-methoxyethyl Acrylate) (PMEA) Analogues

“…[23] They attributed the exothermic peak in the DSC heating profile of hydrated PMEA to the crystallization of water molecules to form the hexagonal crystal of ordinary ice. [23] Therefore, it is safely assumed that the exothermic peak at À40 8C for hydrated PMEA analogues is attributed to the cold crystallization of water molecules. In the present study, the amounts of intermediate water and non-freezing water in hydrated PMEA analogues were quantified by using the equations showed in the method part.…”