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New poly(1,3,4‐oxadiazole)s bearing pentadecyl side chains: Synthesis and characterization
Author(s) -
More Arvind S.,
Me Shamal K.,
Wadgaonkar Prakash P.
Publication year - 2011
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.34682
Subject(s) - oxadiazole , dimethylacetamide , polymer chemistry , tetrahydrofuran , isophthalic acid , chemistry , chloride , chloroform , pyridine , side chain , terephthalic acid , inherent viscosity , ether , glass transition , polymer , intrinsic viscosity , organic chemistry , polyester , solvent
The 4‐[4′‐(Hydrazinocarbonyl)phenoxy]‐2‐pentadecylbenzohydrazide was polycondensed with aromatic diacid chlorides viz. , terephthalic acid chloride (TPC), isophthalic acid chloride (IPC), and a mixture of TPC : IPC (50 : 50 mol %) to obtain polyhydrazides which on subsequent cyclodehydration reaction in the presence of phosphoryl chloride yielded new poly(1,3,4‐oxadiazole)s bearing flexibilizing ether linkages and pentadecyl side chains. Inherent viscosities of polyhydrazides and poly(1,3,4‐oxadiazole)s were in the range 0.53–0.66 dL g −1 and 0.49–0.53 dL g −1 , respectively, indicating formation of medium to reasonably high molecular weight polymers. The number average molecular weights ( M n ) and polydispersities ( M w / M n ) of poly(1,3,4‐oxadiazole)s were in the range 14,660–21,370 and 2.2–2.5, respectively. Polyhydrazides and poly(1,3,4‐oxadiazole)s were soluble in polar aprotic solvents such as N , N ‐dimethylacetamide, 1‐methyl‐2‐pyrrolidinone, and N , N ‐dimethylformamide. Furthermore, poly(1,3,4‐oxadiazole)s were also found to be soluble in solvents such as chloroform, dichloromethane, tetrahydrofuran, pyridine, and m ‐cresol. Transparent, flexible, and tough films of polyhydrazides and poly(1,3,4‐oxadiazole)s could be cast from N , N ‐dimethylacetamide and chloroform solutions, respectively. Both polyhydrazides and poly(1,3,4‐oxadiazole)s were amorphous in nature and formation of layered structure was observed due to packing of pentadecyl chains. A decrease in glass transition temperature was observed both in polyhydrazides (143–166°C) and poly(1,3,4‐oxadiazole)s (90–102°C) which could be ascribed to “internal plasticization” effect of pentadecyl chains. The T 10 values, obtained from TG curves, for poly(1,3,4‐oxadiazole)s were in the range of 433–449°C indicating their good thermal stability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci 124:1281–1289, 2012