Synthesis And Properties Of Sulfonated Polymers Based On Sulfur Trioxide

Sulfonation modification of polymers is an effective method to endow polymers with acidity and improve their hydrophilicity.In this thesis,sulfur trioxide(SO₃)was used as sulfonating agent to synthesize sulfonated polymer and its properties were studied.The catalytic performance of glyceryl acetate catalyzed by self-made sulfonated polyphenylene sulfide nonwoven fabric(SPSSF)as solid acid catalyst and the sulfonated synthesis process and the influence of SO₃ on the synthesis of polyethersulfone(PES)and performance were mainly studied.The main research results were as follows:(1)Study on esterification of acetic acid(HOAc)and glycerol catalyzed by SPSSF.In the previous work of our laboratory,the heterogeneous catalytic preparation of sulfonated polyphenylene sulfide nonwovens was completed.On this basis,the synthesis of glycero acetate was carried out by using the synthesized SPSSF as solid acid,glycerol and acetic acid as reactants.The effects of the amount of catalyst,reaction temperature,molar ratio of glycerol to HOAc and the reaction time on the esterification were studied in detail.On the basis of single factor,the process of esterification was optimized by response surface methodology,and the kinetic model of esterification was established.The results showed that the optimal reaction conditions were as follows:the amount of SPSSF catalyst was 3 g,the molar ratio of glycerol to HOAc was 1:6(glycerol 0.1 mol),the reaction temperature was 110?,and the reaction time was 2 h.At this time,the conversion of glycerol reached 96%,and the absolute error was 0.8%compared with the predicted value(96.8%),indicating that the response surface optimization of the process parameters for the esterification of glycerol with HOAc catalyzed by SPSSF has high accuracy and effectiveness.Under the optimum conditions,the selectivity of diacetin(DAG)was 56.1%.The repeated use test showed that after 5 cycles,the conversion of glycerol and the selectivity to monoacetin(MAG),DAG and triacetin(TAG)did not decrease significantly.The experimental results are better than the existing experimental techniques.The esterification reaction conformed to the second-order kinetic reaction and was controlled by chemical reaction,and the activation energy of the reaction was 23.69k J/mol.(2)The effect of SO₃ on the sulfonation process of PES and its properties.PES is a kind of membrane forming material with excellent performance.The permeability and anti fouling properties of the membrane materials can be significantly improved by improving their hydrophilic properties.Therefore,the sulfonation modification of PES has attracted extensive attention.In this work,SO₃ was used to sulfonate PES under mild conditions.Based on the difference of solubility parameters between PES and sulfonated polyethersulfone(SPES),SPES with certain sulfonation degree(DS)were directly separated from the reaction system to realize the integration of reaction and separation.The effects of SO₃/PES mass ratio,reaction temperature and reaction time on the ion exchange capacity(IEC)and DS were discussed.XPS,NMR and FT-IR showed that SPES was successfully synthesized.It was found that SPES with different DS could be obtained by adjusting the process parameters and directly separated from the reaction system,and the recovery and reuse properties of sulfonated solvent and sulfonating agent were studied.The PES/SPES ultrafiltration membrane was prepared by blending SPES and PES,the separation performance and hydrophilicity of the PES/SPES ultrafiltration membrane were significantly improved.The results show that the solid-phase sulfonation and liquid-phase sulfonation of sulfur trioxide have the advantages of simple synthesis process,high efficiency,environmental protection,mild conditions and simple post-treatment.The prepared SPSSF and SPES have good application prospects.