Preparation And Performance Of Hypercrosslinked Polyaniline

In this thesis,the reduced-state polyaniline is used as the construction unit,and the octavinylsilsesquioxane?OVS?is added as a cross-linking agent,and argon is introduced for protection,and the hypercrosslinked polyaniline?LHPPs?is prepared by the friedel-carfts alkylation reaction under the catalysis of the aluminum trichloride.The physical and chemical properties of hypercrosslinked polyaniline were measured by fourier-transformed infrared?FT-IR?spectra,ultraviolet spectroscopy?UV-vis?,Field-emission scanning electron microscopy?FE-SEM?graphics,field-emission scanning electron microscopy?FE-SEM?graphics,Thermal gravimetric analysis?TGA?and nitrogen adsorption and desorption.The results show that the reduced Polyaniline reacted with OVS successfully,and the specific surface area and pore volume of hypercrosslinked polyaniline increase with the increase of the mass of OVS.The synthesized LHPP-1 to LHPP-3 have a specific surface area in the range of 147-388 m²g^-1and a pore volume in the range of 0.13-0.44 cm³g^-1.When the mass of the added OVS is 70%of the mass of the reduced polyaniline,the specific surface area of the hypercrosslinked polyaniline reaches a maximum of 338 m² g^-1.The prepared hypercrosslinked polyaniline was used for Cr???adsorption.Firstly,the effects of different pH values on the adsorption of Cr???by hypercrosslinked polyaniline were studied by using LHPP-3 as the representative.The results showed that LHPP-3 had pH responsiveness to Cr???adsorption,and when pH 1 The cross-linked polyaniline adsorbed the largest amount of Cr???,which was 558.7 mg g^-1.The different components of the hypercrosslinked polyaniline have a significant impact on the adsorption experiments,because LHPP-1 contains the most amino groups and therefore has the highest adsorption capacity for Cr???(963.7 mg g^-1).The adsorption of Cr???by LHPP-1 accords with the pseudo second-order kinetic model and the Langmuir adsorption isotherm model,indicating that one Cr???can be combined with two adsorption sites and the adsorption process is chemisorption.By studying the adsorption process at different temperatures,it is found that the adsorption process of Cr???by LHPP-1 is spontaneous endothermic.When other cations or anions coexist with Cr???,the effect of LHPP-1 on Cr???adsorption is not significant,indicating that LHPP-1 is selective for Cr???adsorption.The recycling experiments of LHPPs show that the prepared hypercrosslinked polyaniline has recyclability and can maintain 90%adsorption after four cycles.The mechanism study on the adsorption of Cr???by LHPP-1 shows that the adsorption is mainly divided into three steps:first,Cr???adsorbs to each other by electrostatic attraction with the-NH⁺=/-NH₂⁺-group of the adsorbent;secondly,Most of Cr???accepts electrons from the-NH-unit and then reducted to Cr?III?,while-NH-is oxidized to-N=units;finally,most of the Cr?III?cations chelate with in LHPP-1-N=Ph=N-unit.The electrochemical properties of hypercrosslinked polyaniline were studied by LHPP-3.Cyclic voltammetry shows that the prepared hypercrosslinked polyaniline has good rate performance.The electrochemical Nyquist diagram shows that the prepared hypercrosslinked polyaniline has a lower electrical resistance than the eigenstate polyaniline.At a current density of 2 A g^-1,the specific capacitance of the LHPP-3electrode is 338 F g^-1,which is higher than the specific capacitance(225 F g^-1)of the eigenstate polyaniline electrode.LHPP-3 has a higher specific capacitance retention than polyaniline electrodes.