A novel class of crosslinkable poly(phthalazinone ether ketone)s with relative high molecularweight and good solubility were successfully synthesized by the copolymerization of bisphthalazinone containing monomer, 3,3 0 -diallyl-4,4 0 -dihydroxybiphenyl and 4,4 0 -difluorobenzophenone. The synthesized polymers with inherent viscosities in the range of 0.42 to 0.75 dL/g can form flexible and transparent membranes by casting from their solution. The crosslinking reaction of these polymers can be carried out by thermally curing of the virgin polymers in or without the presence of crosslinking agent. The experimental results demonstrated that the crosslinking reaction also occurred to some extent during the polymerization. The crosslinked polymers exhibited equivalent glass transition temperature (T g ) at lower crosslinking density, and showed higher T g than virgin polymers at higher crosslinking density. The crosslinked high-temperature polymer can be used as the base material for high temperature adhesive, coating, enamel material, and composite matrices.
A reactive poly (ether ether ketone) PEEK with pendant propenyl groups was prepared by nucleophilic aromatic substitution of 4, 4’-Difluorobenzophenone (DFBP), diallylbisphenol A (DABPA) and bisphenyl A (BPA) as monomer. The prepared reactive PEEK with varying proportion was introduced to toughen bismaleimide (BMI) resin composing of 4,4'-bismaleimidodiphenyl methane (BMDM) and DABPA by melt technique without any solvent. The properties of the BMI resin as a function of the reactive PEEK concentration were evaluated. The presence of PEEK heightened the temperature of “ene” reaction for BMI and DABPA and slightly lowered the glass transition temperature (Tg) of the blends. The impact strength and fracture toughness were highest elevated from 9.0 KJ/m2and 186 J/m2to 15.2 KJ/m2and 239 J/m2 by 10 phr PEEK, respectively. At the same time, the thermal stability was improved by increasing the proportion of the PEEK. Scanning electron microscopy (SEM) of fracture surface revealed that the blends have good interfacial adhesion.
A series of hybrid membranes with special microstructure, based on sulfonated poly (fluorenyl ether ketone) ionomer (SPFEK, IEC=1.74 mequiv.g-1) and secondary amine group containing SiO2(SiO2–NH–NH2), has been successfully designed and prepared for vanadium redox flow battery (VRB) application. The hybrid membranes are prepared by simply adding KH792 into the SPFEK solution in N,N’-dimethylacetamide (DMAc), followed by dispersion, co-condensation and solvent casting. The water uptake, mechanical property, proton conductivity, (VO)2+permeability and single cell performance are investigated in order to understand the relationship between morphology and property of the membranes. The hybrid membranes show dramatically improved proton selectivity when compared with SPFEK. The vanadium ion (VO)2+permeability through the hybrid membrane is about 10 times lower than that of virgin SPFEK. The columbic efficiency and energy efficiency of the single cell of the hybrid membrane are higher than the SPFEK membrane. The results inidicate that hybrid membranes of this type are promising for VRBs.
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