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The review summarizes the various methods of preparing wholly aromatic polyamide -- hydrazides (PAHs). Polyhydrazides are a class of polymers that possess in their repeating units one amide ( -- NHOC -- ) and one hydrazide ( -- CONHNHOC -- ) linking bond between appropriate aromatic nuclei. The review provides several figures of different molecular structures of PAH and expounds the methods of polymerization, low, high temperature, and phosphorylation polycondensation methods. Polyhydrazides exhibit some unique and potentially useful properties such as outstanding thermal and thermooxidative resistance, very high mechanical strength, and ultrahigh moduli. PAHs undergo structural transformation into poly(amide-1,3,4-oxadiazole)s upon heating, which are also considered highly thermally stable polymers. The review presents a description of the structure -- property relation of PAHs. The application of PAHs in reverse osmosis applications has been discussed, as well as the preparation of fibers and metallized PAHs films. Modification of the PAH with carbon nanotubes and graphene and the future prospects for PAHs were introduced with comprehensive references pertaining to this area of research. [ABSTRACT FROM AUTHOR]

Poly(amide-hydrazide)s copolymers were prepared using hydrazide derivative of phenylene diamine to react with aromatic diacid chloride. The wholly aromatic poly(amide-hydrazide)s have better solubility in organic polar solvents, such as N, N-dimethylacetamide, dimethylsulfoxide, 1-methyl-2-pyrollidone, and N, N-dimethylformamide, at room temperature, while still maintaining their high thermal stability. Graphene in the nano size was used as a filler to enhance their thermal and mechanical properties. The polymers as well as the composite were characterized by spectral and mechanical tools as well as by X-ray analysis. POLYM. COMPOS., 38:1311-1318, 2017. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Siliconized epoxy matrix systems have been developed using diglycidyl ether bisphenol A LY556 epoxy resin as a base, hydroxyl-terminated polydimethylsiloxane as modifier, and γ-aminopropyltriethoxysilane as cross-linking agent together with dibutyltin dilaurate as a catalyst. Triethylene tetramine was used as a curing agent. Electrical-resistant glass (E-glass) and ultra-high-molecular-weight polyethylene (spectra)-reinforced composites are fabricated by hand-layup technique using the siliconized epoxy matrix systems. The effect of siloxane and the two fibers on the thermal and morphological characteristics of the siliconized epoxy polymer composites were studied using thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy. The study reveals that the thermal stability of the epoxy systems is enhanced when siloxane is incorporated in them. Morphological studies show that the E-glass fiber reinforcement has better intermolecular adhesion to the epoxy resin than spectra reinforcement due to the presence of ionic sites. [ABSTRACT FROM AUTHOR]