Synthesis And Properties Of Multi-Copoly(Aryl Ether)s Containing Phthalazinone Moieties

Poly(aryl ether)s have presented outstanding combination properties,especially in thermal stability and mechanical property.They have become important polymeric materials universally applied in aerial industry,electric engineering,nuclear energy,chemistry, automobile,etc.During the science advancement of 85's and 95's,Our workteam have developed a novel poly(aryl ether)s with twisted non-coplanar structure which show excellent thermal properties and satisfactory solubility.However,They have the problem of poor melting processability because of high melt viscosity.First,from molecular aspect,a novel copolymer-PPBES has successfully been synthesized by nucelophilic substitution reaction with biphenol(BP),4-(4-hydroxyphenyl) -phthlazin-1(2H)-one(DHPZ) and 4,4'-dichlorodiphenylsulfone(DCS),which has both twisted and linear molecular structures in the backbone.The structures of PPBES copolymers have been confirmed by FT IR,¹H-NMR and elementary analysis techniques.PPBESs show amorphous nature determined by wide angle X-ray diffraction(WAXD).The results of dynamic mechanical thermal analysis(DMTA) show that the copolymers exhibit high storage modulus,and PPBESs are probably minute block copolymers containing PPSU segments in the main chains.In this thesis,the influence of reaction factors on molecular weight(Mw),on molecular weight distribution(PD)and on cyclics content have been studied in details.In the period of initial concentration 10%going up to 50%,the Mws are effected significantly and PDs change from wide to narrow accordingly,when initial concentration reaches to 60%,PD can be controlled at about 3.The cyclics content decrease strikingly with initial concentration increasing.The test result show higher initial reaction concentration adopted can control the cyclics content effectively and PD values.GPC results show that Mws of copolymers increase with polymerization time within given time prolonged,and PD widens.The values of Mw and PD of the copolymers increase before decrease with biphenyl moiety content going up from 20%to 100%.Cyclics content of these copolymers increase with phthalazinone content going up.The thermal stability of the end-capped copolymers is improved after inletting chloromethane gas under certain conditions.In addition,The metal ions in the polymers can be removed off effectively by using de-ionized water with 1%HCl. On the basis of statement above,the effect of molecular structure on property has been studied.PPBES copolymers are soluble in a variety of aprotic polar solvents,such as N-methyl-2-pyrrolidinone(NMP),chloroform and N,N-dimethylacetamide(DMAc),etc., Solubilities improve with the increase PPSU segment content in the main chain in such solvents as THF and DMSO.And the thermal properties have been characterized through differential scanning calorimetry(DSC) and thermogravimetric analysis(TGA),the results show that Tgs of the copolymers can be controlled by changing DHPZ and BP monomers feeding ratios,the Tgs can be adjusted between 234～305℃which is higher than T_g value of PPSU(220℃).The molecular weights(Mws) of PPBES 6040(DHPZ/BP,60/40 molar ratio) are controlled by excessive molar DCS.GPC results show that the Mws,T_gs and cyclics content of copolymers are decreased with increasing molar proportion of DCS,but PD is widened.The thermal stability test shows Mws increase and PD widen by either increasing test time or elevating test temperatures.The results of HAAKE rheological property tests show the melting viscosities of copolymers increase with incresing Mws or decrease with increasing biphenyl group content in the backbone.This phenomenon accounts for Mw effect on melt viscosity severely and by inducing PPSU segment into main chain can improve melt processability.The copolymers can be processed by thermal molding and injection molding.The extruded "fiber" has satisfactory flexibility and intensity.And the values of tensile-strength of PPBES copolymers are higher than PPSU.Second,copoly(aryl ether sulfone ketone)(PPBESK) containing phthalazinone and biphenyl moieties has been synthesized by nucelophilic substitution reaction with BP,DHPZ, DCS and 4,4'-difluorobenzophenone(DFK),and one-step(PPBESK-â… ) and two-step (PPBESK-â…¡) feeding methods have been adopted respectively.The obtained copolymers are characterized by FT IR,¹H-NMR,DSC and TGA techniques.PPBESK-â… s are only soluble in TCE,NMP and pyridine solvents but not totally soluble in chloroform and DMAc.And the melting points of PPBESK-â… s can be observed in the range of 300～320℃from DSC results, and the degradation temperatures(T₅%) are above 490℃under the atmosphere of N₂.For the PPBESK-â…¡s,the solubility is greater improved than PPBESK-â… s.WAXD test approves copolymersâ…¡amorphous conformation.The GPC data show Mws of PPBESK-â…¡s decrease before increasing by increasing sulfonyl and phthalazinone content.All PPBESK-â…¡s exhibite excellent thermal properties with T_gs between 252～269℃and the degradation temperatures (T₅%) are above 480℃in nitrogen atmosphere.DMTA results exhibite that the storage modulus of PPBESK-â…¡s are high.The primary and minute transition peaks resulted from the main chain motion and minute segment motion can be observed in the scanning temperature period. Rheological test results show the melt processability of the copolymer has been improved owing to incorporation PPSU segment in the main chain.And mechanical test results indicate the tensile strength and flexural strength of copolymers decrease with increasing biphenyl content in the backbone.Based on the research above,Poly(aryl ether)s containing phthalazinone and biphenyl moieties exhibite satisfactory mechanical properties,high thermal properties and improved melt processabilities.