Furan-based Polysemiacylcarbazides by Polyaddition of Bis(furanic hydrazide)s with Diisocyanates

Abstract

A solution polyaddition procedure was applied to prepare furanic polyacylsemicarbazides based on 2,2 -isopropylidene-bis(5-(2-furoyl) hydrazide) and aliphatic or aromatic diisocyanates. Model compounds were prepared to facilitate the synthesis and the characterization of the polymers. A systematic study of reaction parameters (the nature of the organic phase, the temperature, the reaction time, and the concentration of monomers) was carried out. High MW polymers were obtained after 12 h reaction at 20 • C with 0.2 M monomer solutions in dimethylacetamide. In fact, the polyacylsemicarbazides obtained had inherent viscosities ranging from 0.63 to 0.85 dL/g. There showed good solubility in aprotic polar solvents. The 1 H and 13 C-NMR spectra were consistent with the expected structures. These furan-based polyacylsemicarbazides are thermally stable up to 290 • C, but exhibit a complex thermal behavior. This was explained by the cyclohydration of acylsemicarbazide groups into NH-substituted oxadiazoles, resulting in rigid and high melting polymers, less stable, however, than conventional aromatic polyoxadiazoles.

Alternative Monomers Based on Lignocellulose and Their Use for Polymer Production

“… Thus, the dimer is highly stable and can be employed in melt polymerization. The corresponding diacid chloride has also been prepared and applied for the polymerization with bisphenol type diols and diamines. − Conversion of the ester with hydrazine yields the corresponding hydrazide which has been applied for the synthesis of novel poly­(hydrazides) and polysemiacylcarbazides …”

“…449−452 Conversion of the ester with hydrazine yields the corresponding hydrazide which has been applied for the synthesis of novel poly-(hydrazides) 453 and polysemiacylcarbazides. 454 Also more recently FCA dimers have been used in the synthesis of various copolymers, for example, in block copoly(esters) with PET, 455 random copolymers with TPA by melt condensation, 456,457 copolymers with sulfonated isophthalic acids, 458,459 and copolymers with hexamethylene diamine and ethylene glycol. 460 3.1.6.…”