Aromatic polyesters containing pendant azido groups: synthesis, characterization, chemical modification and thermal cross-linking

TitleAromatic polyesters containing pendant azido groups: synthesis, characterization, chemical modification and thermal cross-linking
Publication TypeJournal Article
Year of Publication2019
AuthorsNagane, SS, Verma, S, ,, Sane, PS, Dhanmane, SA, Wadgaonkar, PP
JournalEuropean Polymer Journal
Volume116
Pagination180-189
Date PublishedJUL
Type of ArticleArticle
ISSN0014-3057
KeywordsAromatic polyester, Chemical modification, Click chemistry, Pendant azido group, Thermal cross-linking
Abstract

A partially bio-based bisphenol containing pendant azido group viz., 4,4'-(5-azidopentane-2,2-diyl) diphenol (AZBPA) was synthesized starting from 4,4'-bis (4-hydroxyphenyl) pentanoic acid. AZBPA was reacted with isophthaloyl chloride (IPC), terephthaloyl chloride (TPC) and a mixture of IPC/TPC (50:50 mol%) by phase transfer-catalyzed interfacial polycondensation route to obtain aromatic polyesters containing pendant azido groups. Copolyesters containing pendant azido groups were also synthesized by polycondensation of different molar proportions of AZBPA and commercially available 4,4'-(1-phenylethane-1,1-diyl) diphenol (BPA-AP) with IPC. Inherent viscosities and number average molecular weights of (co)polyesters were in the range 0.85-1.64 dL/g and 58,900-190,400, respectively, indicating the formation of reasonably high molecular weight polymers. Tough, transparent, and flexible films could be cast from chloroform solutions of these polyesters. X-Ray diffraction analysis showed that (co)polyesters were amorphous in nature. (Co)polyesters were characterized using FT-IR, H-1 NMR spectroscopy, XRD, TGA and DSC analysis. The chemical modification of a representative copolyester containing pendant azido groups was carried out quantitatively using copper-catalyzed azide-alkyne cycloaddition (CuAAC) with two alkynes viz., phenyl acetylene (PA) and ethynyl-4-nitrobenzene (ENB). Additionally, (co)polyesters containing pendant azido groups were thermally cross-linked (170 degrees C/12 h) leading to the formation of network structures based on azide to nitrene decomposition and subsequent reactions on polyester backbone. The selected cross-linked polyesters were characterized by stress-strain measurements. The cross-linked polymers exhibited higher tensile strength and Young's modulus and lower % elongation at break compared to corresponding pristine polyesters containing pendant azido groups.

DOI10.1016/j.eurpolymj.2019.04.019
Type of Journal (Indian or Foreign)

Foreign

Impact Factor (IF)

3.621

Divison category: 
Polymer Science & Engineering