Synthesis and Characterization of certain Biodegradable Thermotropic Liquid Crystalline Random Copolyesters

Abstract

A series of high molecular weight copolyesters were prepared from isophthalic acid, 1,4-butane diol and sebacic acid/ adipic acid through a two step process of melt polycondensation using titanium tetra butoxide as catalyst. The synthesised random copolyesters were characterised by means of IR, 1 H NMR, 13 C NMR, gel permeation chromatography (GPC), viscosity measurements, differential scanning calorimetry (DSC), thermogravimetry (TG) and X-ray diffraction (XRD) studies. The effect copolymer composition on the physical and thermal properties, as well as enzymatic degradation was investigated. The enzymatic degradation was performed in a buffer solution with enzyme Candida cylindracea lipase. The phase behaviour of the polymers was studied by differential scanning calorimetry and optical polarising microscopy equipped with a heating stage. The copolyesters exhibit thermotropic liquid crystalline behaviour with nematic texture as observed by optical polarising microscopy.

Antioxidant Properties of Indole-3-Acetic Acid based Biopolymeric Hydrogels

“…The alcoholic group (-OH) from diol appeared at 4.107-4.196 ppm which has considered as -OH peak from diol [24]. The departure of centre carbon hydroxyl group from citric acid as proved as vanished peak of 4 ppm [25]. The multiple peaks of -CH 2 proton contributed from citric acid observed in the range of 2.514-2.934 ppm.…”

Grafting Copolymerization of Hydrophilic Monomers Onto Alginate for Modification it's Structure

“…The existence of a rather sharp intense peak at 1280 cm -1 (Sulfonic groups) and 1673 cm -1 (carboxamide groups) in IR spectra of the graft copolymers is a certain evidence of grafting. This absorption band arises from stretching vibration mode of the sulfonic and carboxamide groups related to acrylamide and 2-Acrylamido-2-methyl propan Sulfonic acid monomers respectively [12][13][14][15][16] . Most of the other peaks are related to the protein backbone.…”

“…However, upon further increase in the substrate concentration, increase in the reaction medium viscosity restricts the movements of macroradicals leading to decreased grafting ratio and add-on values. It also may be attributed to deactivation of the macroradical growing chains (e.g., by transfer reactions, combination and/ or interaction with the primary radicals) soon after their formation [9][10][11][12][13][14][15][16][17][18][19] .…”

Synthesis and Characterization of Bioactive Amphiphilic Graft Copolymers with Hydrophilic Poly (1, 3-dioxolane) Side Chains

“…amphiphilic graft copolymers with hydrophilic side chains of defined size, we have chosen a method using a precursory polymer [12][13][14][15][16][17] .…”