@article {42973,
	title = {Synthesis and characterization of polyhydrazides and poly(1,3,4-oxadiazole)s containing multiple arylene ether linkages and pendent pentadecyl chains},
	journal = {High Performance Polymers},
	volume = {29},
	year = {2017},
	month = {SEP},
	chapter = {836-848},
	abstract = {<p>A new diacylhydrazide monomer, namely, 4-(4-(4-(4-(hydrazinocarbonyl)phenoxy)-2-pentadecylphenoxy)phenoxy) benzohydrazide (HPPDPB), was synthesized starting from 4-(4-hydroxyphenoxy)-3-pentadecylphenol. HPPDPB was polycondensed with terephthalic acid chloride (TPC), isophthalic acid chloride (IPC) and a mixture of TPC and IPC (50:50 mol\%) to obtain polyhydrazides containing multiple arylene ether linkages in the backbone and pendent pentadecyl chains. Polyhydrazides were subsequently cyclized in the presence of phosphorus oxychloride to obtain the corresponding poly(1,3,4-oxadiazole)s. Polyhydrazides and poly(1,3,4-oxadiazole)s exhibited inherent viscosities in the range 0.65{\textendash}0.72 dL g-1 and 0.54{\textendash}0.62 dL g-1, respectively, which indicated the formation of reasonably high-molecular weight polymers. Polyhydrazides were soluble in polar aprotic solvents such as N,N-dimethylformamide, N,N-dimethylacetamide (DMAc), 1-methyl-2-pyrrolidinone and pyridine whereas poly(1,3,4-oxadiazole)s exhibited excellent solubility even in common organic solvents such as chloroform, dichloromethane and tetrahydrofuran. Tough, transparent and flexible films of polyhydrazides and poly(1,3,4-oxadiazole)s could be cast from DMAc and chloroform solutions, respectively. X-Ray diffraction studies revealed amorphous nature of polyhydrazides and poly(1,3,4-oxadiazole)s and the formation of layered structure was observed due to ordered packing of pentadecyl chains. The 10\% decomposition temperature (T 10) values for poly(1,3,4-oxadiazole)s were in the range 425{\textendash}440{\textdegree}C indicating their good thermal stability. Glass transition temperature (T g) values of polyhydrazides and poly(1,3,4-oxadiazole)s were in the range 175{\textendash}192{\textdegree}C and 92{\textendash}103{\textdegree}C, respectively. The excellent solubility characteristics and the large gap between T g (92{\textendash}103{\textdegree}C) and T 10 (425{\textendash}440{\textdegree}C) values give poly(1,3,4-oxadiazole)-containing pendent pentadecyl chains better opportunities for processability.</p>},
	doi = {10.1177/0954008316660368},
	author = {Tawade, Bhausaheb V. and Valsange, Nitin G. and Wadgaonkar, Prakash P.}
}
