Preparation And Application Of Porous Organic Materials

With the development of economy,the issues of energy and environmental have become more and more serious.In order to reduce the influence of the greenhouse effect and solve the pollution of the organic gas in the atmosphere,a lot of explorations have been done,especially on the porous organic materials.More and more researchers engaged in the design and synthesis of different types of porous organic materials,the significance of which is not limited in the adsorption of gases,such as carbon capture,hydrogen storage,and the adsorption of organic gases,but extended to catalysis,separation,drug delivery and battery applications and some related areas.However,the rapid development of porous organic materials cannot cover up the challenges in the design,synthesis and applications.For example,how to reduce the production cost of hyper-crosslinked porous polymer and enrich the range of raw materials,which were utilized to prepare ideal porous organic materials with high performance and low cost,to provide the solutions for settling practical problems;in the design stage of porous organic materials,deepen the understanding of the mechanism of pore formation and the utilization of effective means to control pore structures;integrate other methods of pore formation into hypercrosslinked polymers to prepare hierarchical porous materials;actively explore the applications of porous organic materials to solve the current energy and environmental issues,combining with the characteristics and advantages of different kinds of porous organic materials.Around these challenges and problems,the thesis mainly contains three aspects as follows:(1)A new type of porosity-enhanced materials from hypercrosslinked polymer(HCP)precursors were successfully designed and prepared via a two-step strategy.First,the polymer PMS was cross-linked via Friedel-Crafts reaction,yielding a porous polymer;in the second step,chemical etching removed PMS segments and created additional micropores on the HCP(F-HCP).This strategy enriches the range of raw materials for HCPs,and the unique structural feature of PMS offers the opportunity to postmodify the porosity of the prepared HCPs through chemical methods.For example,through changing the cross-linking and etching conditions,the surface areas,pore size distribution,and other properties can be adjusted easily.Because of their large surface areas and favorable pore structures,the PMS-based porosity-enhanced materials exhibit excellent adsorption capacity for CO2 and VOCs,good CO2/N2 selectivity,and superior tolerance to acid.(2)The first novel sulfur-containing porous organic material(S-HCP)was prepared with by-product sulfur and commercial raw bismaleimide as raw material using inverse vulcanization reaction.In the process,sulfur knits bismaleimide,which cannot take place self-polymerization,into three-dimensional network.The rigid skeleton endows the network large porosity(BET specific surface area could reach 450 m2/g).In addition,the heteroatoms,such as nitrogen atoms,could enhance the adsorption performance of sulfur-based porous materials for carbon dioxide and organic vapors.The concept of combining the knowledge of porous materials with the discarded energy and solving the practical environmental problems further expands the application value of the industrial by-product sulfur.(3)Hierarchically porous polymer membranes(HPPM)with micro pores and nano pores were synthesized by a two-step method,which combined BF process with hypercrosslinking posttreatment.One level of uniform macropores was produced by BF process,while the other level of micropores was created via a sequent hypercrosslinking reaction.These two kinds of pore structures in the polystyrene film enhance the adsorption of nitrogen and heat transfer at high temperature,which endowed HPPM with a large specific surface area and excellent chemical and thermal stabilities.The strategy demonstrated the possibility and enriched the methodologies of preparing hierarchically porous materials with different pore forming methods.