Study On Synthesis And Characterization Of Poly(Aryl Ether Sulfone Ether Ketone Ketone)s Having Pendant Carboxyl Groups And Its Adsorption

Poly (aryl ether sulfone ether ketone ketone)s having pendant carboxyl groups (PESEKK-A) attached to the main chain were synthesized by binary copolymerization of trimellitic anhydride chloride (TMAC) with 4,4'-diphenoxy diphenyl sulfone (DPODPS), and ternary polymerization of TMAC, DPODPS with isophthal chloride (IPC)/ terephthal chloride (TPC). The polymerization was low temperature solution polycondensation, using aluminum trichloride (AlCl3) as catalyst, 1,2-dichloro ethane (DCE) as solvent, N,N- dimethyl formamide (DMF) as cosolvent. Considering the application of carboxyl-contaning polymers in fields of ion-exchange and ion-adsorption and the excellent solvent-resistace and corrosion-resistance of PESEKK-A, the load ability of PESEKK-A and its sodium salt PESEKK-Na on Cu2+,Ag+,Cd2+ was studied.Trimellitic anhydride chloride (TMAC) was synthesized by the reaction of trimellitic acid anhydride(TMA) with thionyl chloride(SOCl2), using CMA as catalyst, 1,2-dichloro ethane(DCE) as solvent. TMAC was separated from the reaction system by vacuum distillation. The mass ratio of TMA with SOCl2, the ratio of catalyst (compared with the total mass of TMA and SOCl2 ), temperature and time were 1.34, 0.28%, 100 oC, 10 h, respectively. The structure was confirmed by means of FT-IR, 1H-NMR, 13C-NMR techniques. The melting point of TMAC prepared was 66.5～67.5 oC, and the purity was above 99%, determined by HPLC. The process could be conducted 3 times in the same reaction vessel, and the average yield of TMAC was above 95%. Moreover, the purity kept during the circulation process. The solvent and the excessive SOCl2 could be completely reused without further disposal, additional 1/10 of the original mass of CMA was needed to compensate the loss of CMA when circulation process was conducted.In the binary copolymerization, the molar ratio of TMAC/DPODPS was 1:1. The effect of usage of DMF and concentration of monomers on the molecular weight was studied. FT-IR and 1H-NMR indicate that there exists both meta- and tere- structure unit in the backbone, and the ratio of meta-structure unit is much higher than that of tere-structre unit. The polymer can disovled in few solvents, i.e., concentrated sulfuric acid(98%), dichloroacetic acid and trifluoroacetic acid, shows high solvent-resistant and corrosion-resistant.In the ternary polymerization, two series of PESEKK-A were synthesized over a wide molar ratio of TMAC/TPC, TMAC/IPC. 1H-NMR spectrum indicates that reaction of DPODPS with TMAC exhibits high regioselectivity, produces only meta-orientation of the resulting ketone linkages in the ternary polymerization. When heated, the resulting resins of ternary polymer polymerization can dissolve or swell in DMF, dimethyl sulfoxide (DMSO), N-methyl-pyrrolidone (NMP) and P-xylene besides concentrated sulfuric acid(98%), dichloroacetic acid and trifluoroacetic acid, show better solubility. As ratio of carboxyl increases, the solubility becomes weaker. All the polymers prepared here are amorphous according to the WAXD patterns. The bulky carboxyl greatly destroyed the regularity and leads to the amorphous structure. With the content of TMAC increasing ,Td with 5% weight loss decreases. The carboxyl is the weak point of the chain in thermal oxidation degradation. Use of thermal gravity analysis (TGA) and FT-IR indicates that carboxyl begins to undergo decarboxylation when temperature is about 240℃.Study of load ability shows that the load ability of resin is affected by PH, time, temperature and initial concentration. Sodium salt of the resin (PESEKK-Na) possesses better load ability than PESEKK-A. The favorable PH for load of Cu²⁺,Ag+,Cd²⁺ with PESEKK-Na are 4.7, 4.5 and 5.7,respectively. The maximum load amount of Cu²⁺,Ag+,Cd²⁺with PESEKK-Na are 1.03 mmol/g,0.8153mmol/g,0.5586mmol/g, respectively .The resin can be reused without loss of load ability. Results show that PESEKK-Na has the potential to be applied in fields of separating valuable metals and environmental protection.