An epoxy based on the tetraglycidyl 4,4 0 -diaminodiphenyl-methane (TGDDM)/bisphenol A type novolac(F-51) cured with 4,4 0 -diaminidiphenysulfone (DDS) has been modified with Poly (phthalazinone ether nitrile ketone)(PPENK). The interaction between the PPENK and epoxy resin have been investigated by differential scanning calorimetry (DSC), FT-IR, and dynamic mechanical analysis (DMA). The thermal and mechanical properties were characterized by thermogravimetric analysis (TGA), thermomechanical analysis (TMA), flexural, impact strength, and the critical stress intensity factor tests. The results showed that a large number of physical crosslinks formed by intermolecular and intramolecular hydrogen bonding indeed existed in the TGDDM/F-51/ PPENK blends. These interactions gave good compatibility between PPENK and epoxy resin. So that any phase separation had not been detected by DMA and scanning electron microscope (SEM). Beyond that the interaction could also be a benefit to the thermal and mechanical properties. Compared with the neat epoxy resin, the critical stress intensity factor values reached the maximum at 10-phr PPENK, as well as the impact strength.
New poly(phthalazinone ether ketone)s (PPEKs) with pendent terminal ethynyl groups were synthesized by the aromatic nucleophilic substitution (S N Ar) polycondensation reaction of a new bisphenol monomer, 2-(3-ethynylphenyl)hydroquinone, with 4-(4 ′ -hydroxyphenyl)phthalazin-1(2H)-one and 4,4 ′ -bis(4-fluorophenyl) ketone, followed by click modification reaction with 1-azidopyrene. Fourier transform infrared and NMR spectral data of the model compound indicated that the terminal ethynyl groups were stable in S N Ar reaction conditions, thus allowing the synthesis of the desired polymers. The PPEKs obtained with glass transition temperature (T g ) in the range 152-245 ∘ C were amorphous, characterized by wide-angle X-ray diffraction, and dissolved in organic solvent to cast into transparent and flexible films. Differential scanning calorimetry results indicated that the curing reaction of the terminal ethynyl groups of the copolymers took place upon heating to 250 ∘ C. The T g of cured PPEKs was increased to about 260 ∘ C. They also exhibited excellent thermal stability with 5% weight loss temperatures ranging from 448 to 527 ∘ C in various atmospheres. The PPEKs with pendent terminal ethynyl groups were subsequently functionalized with pyrene through click reaction. A dilute chloroform solution displayed a red-shifted emission profile.
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