Decomposition Temperature Of Blends Research Articles

Crosslinking of alginic acid/chitosan matrices using bis phenol-F-diglycidyl ether: mechanical, thermal and water absorption investigation

In this study, blends of alginic acid (AA) and chitosan (Cs) cross-linked with bis phenol-F-diglycidyl ether (BPFDGE) were prepared by solvent evaporation method. Chemical structure was analyzed by FTIR showing the existence of interaction between chitosan and sodium alginate. Three transition temperatures were observed for the AA/Cs/BPFDGE blend system in differential thermo-gravimetric analysis thermograms. The first transition showed weight loss due to elimination of absorbed moisture and second transition was due to cleavage of glycosidic linkage of chitosan and decarboxylation from polysaccharide backbone of alginic acid. In the third transition, decomposition temperature of blends (769 °C) was higher as compared to chitosan (580 °C) and alginic acid (620 °C). Investigation on mechanical properties of blends revealed a decreasing trend due to alginate addition that alters crystallization as well as molecular orientation in AA/Cs blend. Increased water uptake was observed owing to interaction between cationic (chitosan) and anionic (alginic acid) groups.

Preparation and Characterization of Poly (vinyl chloride) Polyblends with Fractionated Lignin

Soda lignin was divided into three fractions by sequential extraction with i-propanol/ethanol mixture (4:1v/v) and methanol. Blends of poly (vinyl chloride) (PVC) and lignin were prepared from these lignin fractions. The influences of lignin on the processabilities of the blends, as well as on their mechanical performances and thermal properties, were investigated. The lignin fraction with low molecular weight accelerates the plasticization of blend. It can be dispersed in a rather uniformly form in PVC matrix than any other fractions. The blend prepared from low-molecular-weight lignin fraction exhibits higher mechanical performances than those of blends prepared from any other fractions. The initial decomposition temperature of blends shows a slight decrease, while the incorporation of high-molecular-weight lignin fraction improves the maximum decomposition temperature of blend. The heterogeneity of soda lignin results in the deteriorated mechanical performances of the blend prepared from un-fractionated lignin.