Porous Polymers Prepared From C₃-ymmetrical Aromatic Molecules And Their Properties

In recent years,the porous polymer has become one of the highlights in agro-scientific research in the multi-disciplinary.Because of the large specific surface areas,lighter texture,rich porous structures,functional and easy adjustment of the reaction process,the excellent physical and chemical stability,the porous polymers have been one of the highlights and applied in the field of chemistry,material and environment,such as heterogeneous catalysis,photovoltaic materials,chemical/biosensing,electrochromic devices,gas storage/separation,and photodegradation.Therefore,the porous polymers become the most popular directions of research on the development of the porous functional material.The C3-symmetrical compounds have many advantages such as plenty of aromatic rings,unique large ? electron delocalization,and more reactive sites,and thus have a wide range of applications.In this thesis,the C3-symmetrical aromatic compounds were studied to prepare the porous materials,whose properties were also studied.The triphenylbenzene-type compounds(triphenylbenzene,truxene,1,3,5-tris(p-biphenyl)-benzene)were selected as the monomers to prepare porous polymers via a variety of synthesis methods.During the course of the study,it was discovered that the truxene(TN)solution showed the red-shift of the fluorescence from 355 nm to 508.5 nm under sunlight.Therefore we discussed the effects of light and oxygen on the luminescence of truxene in the first part of the thesis.Through the characterization methods,the chemical structure of the product was determined,and the mechanism of photooxidation reaction was discussed.In the second part,on the basis of the synthesis of C3-symmetric aromatic molecules,triphenylbenzene(TPB),and its derivatives tris(4-ethoxyphenyl)benzene(TPB-p-C2),tris(2,5-diethoxyphenyl)benzene(TPB-2C2),tris(p-biphenyl)benzene(TDPB)were applied to prepare the porous polymers by the solid-state oxidative coupling reactions.Firstly,the effect of the oxidative agent amounts on the polymer yields was studied.The amorphous polymers exhibited the excellent chemical and thermal stability.Through BET test analysis,it was found that the polymers prepared by the solid-state oxidative coupling reaction have certain porous properties.Due to the conjugated structures,the polymers exhibited unique fluorescence properties.The triphenylbenzene-type polymers were blue light emitting materials,while the PTDPB displayed green light emitting.The results showed the novel photoelectric materials could be prepared by the novel synthesis route and showed broad application prospects.In the third part of the the thesis,the highly cross-linked polymers were prepared by the C3-symmetric aromatic molecules with methylal(FDA)or dibenzylchlorobenzene(DCX)as the external cross-linking agent by one-step Friedel-Crafts reaction.The characterization and performance tests were carried out.All of these porous materials from C3-symmetric molecules showed the excellent thermal stability and high specific surface areas.The porous polymers with FDA as an external cross-linker had the higher thermal stability than that cross-linked by DCX.Among them,the microporous HCP-TPB and HCP-TDPB had the highest specific surface areas of 968.59 m2 g-1 and 1360 m2 g-1,respectively.The TiO2 coated porous polymers were prepared by a simple sulfonation and sol-gel loading method in the fourth part.The results of SEM,XRD,and EDS analysis confirmed the successful preparation of organic-inorganic composite materials.Compared to the original porous polymers,the composite materials reduced the surface area and porosity by the BET test analysis.The adsorption and catalytic performance of the porous composites were tested.Among them,TiO2@HCP-TPB-FDA had a strong adsorption capacity for malachite green in simulated wastewater.After the adsorption equilibrium,the adsorption capacity reached 46.83 mg g-1.Due to the excellent photoelectric properties of C3-aromatic molecules,the porous composites also exhibited excellent photodegradation ability,TiO2@HCP-TPB-FDA was used to degrade the malachite green solution after 1 h with the degradation rate of 93.59%in a simulated light environment.The degradation of the antibiotic tetracycline HCl aqueous solution by TiO2@HCP-TPB-FDA showed the maximum of degradation with 327.27 mg g-1 under sun light.Beside the more degradation efficiency could be achieved to 588.25 mg g-1 under UV lamp(254 nm).Thereby,TiO2@HCP-TPB-FDA porous composite materials performed the high efficiency in the photodegradation application,and could be applied in the field of environmental protection in the future.