SYNOPSISThe crystalline structure of chitosan membranes made of a high degree of (90%) and low degree of (60% ) deacetylated chitin by various regeneration processes was studied. The results of X-ray and IR spectroscopy investigations testify that the type of crystalline structure, the degree of crystallinity, and the average lateral crystallite size depend basically on the deacetylation degree of the chitin utilized in preparing the membranes. 0 1994 John Wiley & Sons, Inc.
Chitin filaments obtained after alkaline hydrolysis of dibutyrylchitin (DBCH) precursor filaments were investigated. The morphological structure, fine structure, and selected physical and physicochemical properties were studied. The studies of morphological structure included the assessment of the cross-section profile, the length and developing index of the contour line of the cross sections, the appearance of spherolitical crystalline aggregations, and the existence of skin-core building. The appraisal of the fine structure comprised the recognition of the lattice crystal system and the parameters of the unit cell, the crystallinity degree and average lateral crystallite sizes, and the crystalline and amorphous orientation. The characterization of physical properties included the appraisal of density, mechanical, thermal, electrical, and optical properties. In the area of physicochemical properties, swelling and dyeability were examined.
The paper deals with the assessment of the surface modification of glossy continuous poly(ethylene terephthalate) fibers from the point of view of changes in their surface structure in terms of its micro-topography and the molecular and supermolecular structure of the filament surface layers. The performed SEM and AFM investigations have shown differences in the fiber surface carving before and after modification (smoothing or increased roughness), depending on the type of applied enzymatic preparation. Measurements with the use of the ATR-IR method have shown changes in the physicochemical character of the investigated fiber surface. The cleavage of the ester bonds in PET macromolecular chains, resulting from the modifications used, leads to the formation of reactive AOH and ACOOH groups.
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