Preparation And Properties Of Energy Storage Polymer Adsorbents

In recent years,the adsorption and recovery of volatile organic compounds(VOCs)has become a research hotspot.The traditional adsorbents such as activated carbon have some problems in the process of adsorption,such as:high thermal effect,blockage of carbon pores by reaction with active substances,difficult desorption,short service life,easy to cause spontaneous combustion in adsorption process,and so on.Polymer resins are widely used for the adsorption of VOCs due to their high specific surface area,controllable pore structure,and easy desorption and regeneration.However,there is a problem of adsorption exotherm and desorption endotherm in the adsorption process.If this part of the heat is not utilized reasonably,not only the adsorption capacity will be lowered,but also the temperature will be too high,and the adsorbent will explode and ignite.The phase change energy storage microcapsule(simplified as PCESMs)is a kind of material which stores the temporarily unused heat and releases it by some means when necessary.Paraffin wax is widely used as the core material of PCESMs because of its high heat storage ability,easy to obtain,cheap and wide range of phase change temperature.Combining PCESMs with polymer resin to prepare energy-stored polymer adsorbent can solve the exothermic-endothermic problem of polymer adsorbent in the process of adsorption-desorption,thereby increasing the adsorption capacity of the polymer adsorbent.In this paper,PCESMs with 58#paraffin wax as core material and polystyrene as shell material were prepared by suspension polymerization.Then PCESMs and polyvinyl benzyl chloride adsorbent were combined to prepare energy storage polymer adsorbents,the aspect of increasing the surface area of the energy storage polymer adsorbent and improving its adsorption performance was explored.The morphology,latent heat of phase change,specific surface area and pore size were characterized by optical microscopy,differential scanning calorimetry(DSC)and nitrogen adsorption desorption.The specific work is as follows:The PCESMs with paraffin as the core material and polystyrene as the shell material were successfully synthesized by suspension polymerization.By changing the stirring speed,paraffin doping amount and the ratio of styrene(St)and divinylbenzene(DVB),the optimal conditions for preparing high phase transition latent heat were explored:when the stirring speed was 400 rpm,the paraffin doping amount for 10 g and the ratio of St to DVB is 1:1(St and DVB are both 10 g),the PCESMs have a good spherical shape and the latent heat of phase change is up to57.68 J/g.The PCESMs prepared by suspension polymerization have simple operation,good thermal stability,high latent heat of phase change and controllable particle size,and have good application prospects in thermal energy storage.The energy storage adsorbent composites of polyvinyl benzyl chloride polymer adsorbent PCESMs was successfully synthesized by suspension polymerization.the heat storage capacity of the energy storage adsorbent is increased by changing the doping amount of the PCESMs,and the specific surface area is increased by post-crosslinking to improve the adsorption performance.When the ratio of vinylbenzylchloride(VBC)to divinylbenzene(DVB)is 3:1,ie VBC is 9 g,DVB is 3g,the doping amount of PCESMs is 4.5 g,the latent heat of phase change of the energy storage type adsorbent reaches 18.75 J/g,the specific surface area is 62.405m~2/g,the pore diameter is 0.881 nm,after post-crosslinking.The specific surface area is increased to 341.796 m~2/g and the pore diameter is 0.880 nm,however,the DSC test results show that the hyper-crosslinked polymer adsorbent has almost no heat storage capacity after post-crosslinking,the possible reason is that during the post-crosslinking process,1,2-dichloroethane destroys the PCESMs,causing the paraffin to flow out,thereby having no heat storage capacity.