The preparation of a new polypropylene-based [PP/P(St-DVB)] sulfonic acid cation exchange membrane is as follows.
Preparation of PP/P(St-DVB) composite membrane: polypropylene microporous membrane was repeatedly impregnated and washed with anhydrous ethanol, and dried under vacuum at 40 ℃ to constant weight. Then the film was immersed in a mixture of styrene monomer, initiator (BPO) and different crosslinking agent (DVB) concentrations for 24h, so that the inside and outside of the film was fully immersed to achieve equilibrium. The glass plate is washed and dried with acetone and distilled water in turn, PSt prepolymer is used as film sealing agent, and the polypropylene film after the monomer is sealed and impregnated with two film plates is used for in-situ polymerization. The polymerization temperature is controlled at 65 ℃, and the temperature is raised to 80 ℃ after 6 hours. After polymerization is completed, the film plate is opened, the film is started, the film is washed and extracted, and transparent PP.
Sulfonation of PP/P(S-DVB) IPN composite membrane: 20ml of 1,2-dichloroethane is added into the reactor, the composite membrane is added to swell for about 30min, 5ml of chlorosulfonic acid is slowly added dropwise at room temperature, and the dropwise addition is stirred for about 20min. The reaction is carried out under stirring for a certain period of time. When the color of the membrane turns yellow, glac, the membrane is then hydrolyzed in NaOH solution to form a Na-type ion-exchange membrane, and the hydrophilicity of the membrane increases. Finally, a sulfonic acid (H) ion exchange membrane was prepared by repeatedly changing with 2mol/L NaOH and 2mol/L HCl.