| Hierarchical porous cabnons (HPCs) combine the advantages of micro-, meso-and/or macro-porous carbons, and exhibit great specific surface area and multimodal pore sizes. HPCs can be widely used in super-capacitors as ideal electrode materials, environmental protection and industrial catalysis. HPCs are mainly prepared by hard template method, soft template method, template-activation combined method and template-free method. Up to now, HPCs with high specific surface area and great pore structures have been reported, and most of them are prepared by hard template method. However, hard template method have some disadvantages, such as multiple steps, high price of hard template and long-time consuming, which restrict its application in industry. Soft template method can prepare HPCs by only one step-carbonization because of the pyrolysis properties of blocks. In this thesis, two series of VDC copolymers were prepared by emulsion polymerizations. After carbonization, VDC copolymers with different compositions were turned into porous carbons. The synthesis of VDC block copolymers by RAFT living polymerization, the relationship between VDC copolymers micro-phase structure and corresponding HPC microstructure and effects of HPC pore structures on its adsorption and electrochemical properties were investigated.Firstly, PVDC-b-PBA copolymers with different block molar ratios were prepared by RAFT emulsion polymerization method, and the mean molecular weight and molecular weight distribution (MWD), micro-phase structures and thermodegradation behavior of block copolymers were analysized. It was found that the PVDC-b-PBA copolymers all had high molar masses and low MWD (PDI<1.90), and the molecular weights of PVDC-b-PBA copolymers were increased with the ratio of monomer/RAFT reagent, indicating the living nature of polymerization. Micro-phase separations of PVDC-b-PBA copolymers were investigated by atomic force microscopy (AFM) and transmission electron microscope (TEM). With the increase of PBA/PVDC ratio, the micro-phase separations changed from PBA dispersed particle phase, PBA dispersed rodlike phase to PBA and PVDC bicontinuous phase. The thermogravimetric analysis (TGA) revealed that PVDC-&-PBA copolymers all have two weight loss periods (240 ℃ and 400℃),which indicated that PVDC-b-PBA copolymers had blocks and micro-phase separations. RAFT micro-emulsion method was applied to synthesize PS nanocapsules. By varying St/HD weight ratios, RAFT concentrations and adding of AA, the optimized conditions for preparation of PS nanocapsules with low polydispersity of PS and complete encapsulation were obtained. Then, PVDC-b-PS copolymer nanocapsules were prepared by RAFT seed emulsion method after swelling VDC monomer in PS seeded emulsion. The effects of VDC/PS-TTCA molar weight ratio and the addition of crosslinking agent (DVB) on polymerization were investigated. PVDC-b-PS copolymers had high PDI and were distributed as multiple peaks.Secondly, VDC copolymers based HPCs were fabricated by carbonizing the VDC copolymers under high temperature, and the microstructure of VDC copolymer based porous carbons were investigated by N2 adsorption-desorption analysis and scanning electron microscopy (SEM). The result showed that PVDC-b-PBA copolymer based carbons exhibited hierarchical pore structure with meso- and micropores. The specific surface areas and pore volumes of HPCs were increased with the increase of PBA/PVDC ratio. The HPCs prepared from PVDC-b-PS and PVDC-g-PS copolymers exhibited interconnected pore structure and high porosity. The carbons prepared from PVDC-b-PS nano-capsules had large pores caused by the assembly of nanocapsules during carbonization, but the specific surface area and total pore volume were both low because of the blocking effect of PAA chians.Thirdly, the adsorptions of VDC copolymer based porous carbons towards tretraalkylammonium ions were investigated. The result showed that specific surface area, pore structure parameters and the size of ions all had effects on the adsorption amount. It was found that VDC copolymer based porous carbons with high ratio of mesoporosity had great adsorption amount of CTAB, which had a long alkyl structure. PVDC236-b-PBA257 copolymer and PVDC-g-PS copolymer based HPC had the highest adsorption amounts in two series of porous carbons, which were 6.19×10-4mol/g and 1.75×10-4mol/g, respectively.Finally, the electrochemical properties of VDC copolymer based porous carbons were investigated by cyclic voltammetry and charge-discharge method, and the specific capacitances were calculated. The results indicated that VDC copolymer based porous carbons all had the properties of ideal capacitors. Among all the porous carbons, PVDC236-b-BA257 copolymer based HPC had the highest capacitance of 170F/g under the condition of 0.5 A/g current density and PVDC-g-PS copolymer based HPC also had high capacitance of 146F/g at 0.5A/g current density. PVDC-b-PS copolymer based HPC which owned the highest meso-pore ratio (81%), had the most stable capacitance with the increase of current density. |
