Preparation Of Oriented Porous Polystyrene And Its Application In Synthesis Of Aligned One-dimensional Materials

At present,there were many researches on nano-scale porous materials and nano-scale aligned one-dimensional materials,and less researched on micro-scale porous materials and aligned one-dimensional materials.In this project,a kind of directionally arranged porous polystyrene material with a diameter of micrometers and a length of centimeters was prepared,and the application potential of this material as a filter material was studied,and then the directionally arranged microtubule materials were synthesized by template synthesis method.The physical and chemical phenomena and principles in the process of synthesizing microtubule materials and the application of the obtained microtubule materials.This subject mainly includeed the following three aspects.Firstly,a commercial polyacrylonitrile(PAN)fiber with a diameter of about 20 ?m was used as a template,and it was immersed in styrene.After bulk polymerization of styrene,the product was placed in N' N-dimethylformamide(DMF)and dimethylformamide at 50?.The oriented porous polystyrene material was prepared by etching in a mixed solution of sulfoxide(DMSO)for 3 d.Through SEM observation,the pore size distribution of the oriented porous polystyrene was uniform,the channels were arranged vertically,and the two ends were connected.Compression test results showed that the mechanical strength of oriented porous polystyrene was anisotropic,and the elastic modulus in the axial direction(8.2 MPa)was greater than that in the radial direction(0.4 MPa).Filtration experiments using polydisperse polystyrene microspheres as samples showed that this anligned arrangement of porous polystyrene can screen polystyrene microspheres larger than 19 ?m,showed good filtration performance.Using aligned porous polystyrene as a template,ultralong aligned mesoporous bioactive glass tubes(AMBGTs)with a length of about 8 mm were fabricated.The structure and composition of AMBGTs were tested by SEM,TEM,SAXS and BET.The tube diameter of AMBGTs was about 15 ?m,and there was an ordered mesoporous structure on the tube wall,which can increase its specific surface area.Through EDS and Mapping test results,it was found that the element distribution of AMBGTs was uniform,and the actual composition was close to the theoretical value.Mineralization experiments were performed on AMBGTs by preparing simulated body fluids(SBF),which showed good in vitro bioactivity.Due to the tubular macroporous and mesoporous structure of AMBGTs,its specific surface area was large(240.98 m2/g),which was suitable for drug carrier materials.Using ibuprofen(IBU)as the drug loading model,the drug loading and release behaviors of AMBGTs were studied.The results showed that the release of IBU had the characteristics of fast at first and then slow,which was in line with the Fick diffusion model without solvent erosion.Finally,by controlling the contact time of styrene and PAN fibers before polymerization and the time of PAN etching,N-doped carbon microtubes(CMT)were prepared after carbonizing aligned porous polystyrene under N2 atmosphere,and then passed through 5 M nitric acid.Modified carbon microtubes(MCMT)were obtained by reflux modification of CMT.The BET test results showed that there were mesopores on the MCMT tube wall,the specific surface area was 28.31 m2/g and the average pore size was 3.5 nm.The adsorption behavior of cationic dyes methylene blue(MB),rhodamine B(RhB)and anionic dye methyl orange(MO)was studied using MCMT as adsorbent.Under the condition that the initial concentration of MB was 20 mg/L,the adsorption capacity of MCMT for MB in alkaline environment was 5 times higher than that in acidic or neutral environment.When the pH value was 8,the maximum adsorption capacity of MCMT for MB was 1875.4 mg/g,and it hardly adsorbs RhB and MO.MCMT has the characteristics of high adsorption capacity and high selectivity for MB.According to the detection results,it was speculated that the selective adsorption of MB by MCMT was related to the molecular size and charge of the dye.The fitting results of adsorption isotherms and adsorption kinetics showed that the adsorption behavior of MB by MCMT belonged to monolayer adsorption and was controlled by chemical factors.