Synthesis And Properties Of Copoly(Phthalazinone Ether)S Containing Biphenyl Moiety

Poly(arylene ether)s (PAEs) are one of the most important families of high performance engineering thermoplastics due to the combination of properties such as relatively low cost,good processability,high thermal stability and good machanical performance.Poly(phthalazione aryl ether)s (PPAEs) based on bisphenols containing phthalazionne moiety are a novel class of PAEs developed by Jian et al.,compared with commercial PAEs,PPAEs have high glass transition temperatures and good solubility in organic solvents.PPAEs have been used in high themperature resistant insulant matierials,serpration film and marix for advanced composites.However, the twisted,rigid phthalazione structure in the backbone result in high melt viscosities and poor melt processability.Copolymerizing bisphenols with greater flexibility than DHPZ can improve the processability of PPAEs effectively.In this thesis,several series of copoly(phthalazinone ether)s containing biphenyl moiety in the main chain were synthesized. The influences of introducing biphenyl structure into the main chain of PPAEs on the thermal properties,solubility,crystallity and processabilities were studied.The soluble PEDEK precuesors were synthesized by biphenyl-4,4’-diol (BP) and4,4’-difluoro(N-benzohydroxylidindene aniline)(Ketimine) via nucleophilic polycondensation. A series of block copolymers composed of poly(phthalazinone ether sulfone ketone)(PPESK) and poly(aryl ether ketone) with biphenyl structure (PEDEK) were synthesized by PPESK oligomer and soluble PEDEK oligomers, followed by hydrolysising in mild condition.The structure of block copolymer precursors and copolymers were investigated by FTIR, inherent viscosity,solext test.DSC,TGA, WAXD mearsurements show that there was a gradual descent of glass transition temperature of these copolymers with the increasing content of PEDEK in the main chain.however.the crystallinity measured by WAXD and thermal stability of copolymers increased with the increasing content of PEDEK.The Tgs and Tms of block copolymers are above220℃and below400℃respectively.Three kinds of dihalogen monomers containing biphenyl structure were prepared from BP with4,4’-difluorobenzophenone (DFK),2,6-difluorobenzonitrile (DFBN) and4,4’-dichlorophenyl sulfone (DCS) respectively through pseudo high dilution, and then three dihalogen monomers with4-(4’-hydroxyphenyl)phthalazin-1(2H)-one (DHPZ) were prepared to alternate poly(phthalazinone biphenyl ether)s (a-PPBEs).The structure of momomers and polymers were confirmed by FTIR,NMR etc. Besides, TGA, DCS, DMA tests demosrate that alternate poly(phthalazinone biphenyl ether nitrile)(a-PPBEN) had the best themal property and WAXD tests show that a-PPBEs were amorphous.On the basis of statement above, difuloromonomer containing biphenyl and ketone structure (K-trimer), DHPZ,DCS were synthesized to be a novel series of copolymers called PPBEKSs.The structure and properties of copolymers were investigated by FTIR,NMR, TGA,DSC,WAXD and solubility test. With the increasing content of sulfone unit, their solubility in organic solvent and Tgs increased while their thermal stability decreased.The results of HAAKE rheological tests of alternate poly(phthalazinone biphenyl ether ketone) and PPBEKSs show that the balance torque of copolymers increased and the residence time decreased with increasing content of sulfone group in the backbone, which demonstrate that the processability of PPBEKSs became worse with the increasing molar ratios of DCS to K-trimer.And melting stability of a-PPBEK and PPBEKS(K-trimer/DCS=8/2) was similar to poly(ether sulfone)(PES) but their balance torque were lower than that of PES,which implied that a-PPBEK and PPBEKS(K-trimer/DCS=8/2) had prominent processing performance.