| Hypercrosslinked polymer is considered to be an organic porous polymer material with great development potential for its high specific surface area,mild synthesis conditions,wide sources of reaction monomers,good physical and chemical stability,etc.Friedel-crafts alkylation is usually used in the preparation of traditional HCPs.The reaction needs anhydrous system and the products are mostly hydrophobic framework,which limits the development of its application field to some extent.In this paper,a series of hydroxy rich hypercrosslinked polymers were prepared in aqueous system by phenol formaldehyde polycondensation,the hydration and swelling mechanisms were studied,and their adsorption properties for organic pollutants in aqueous solution were investigated.The details are as follows:?1?Seven hydroxy rich hypercrosslinked polymers with different skeleton structures were prepared by condensation of catechol,hydroquinone,resorcinol and phenol with formaldehyde.The polycondensation products of catechol,hydroquinone and formaldehyde have higher specific surface area,which are 619 m2·g-1 and 852.03m2·g-1,respectively.The formed pores are mainly micropores and low-end mesopores.The specific surface area and surface hydroxyl content of the product can be increased by introducing phenol to the catechol and formaldehyde system.All the product have good swelling properties in ethanol,n-hexane,toluene and water.?2?Based on the theory of multi-body interaction and density functional activity,the synergistic effect of hydrogen bond interaction in hydrate of four model compounds of HF-HCPs unit was studied.The synergistic effect of hydrogen bond interaction plays an important role in the hydration and expansion of HF-HCPs.In the development stage of hydration and swelling process,due to the significant synergistic effect of H2O???H2O,and the stronger H2O???H2O interaction than HF-HCPs???H2O interaction,the change rate of H2O???H2O hydrogen bond interaction is greater than that of HF-HCPs???H2O hydrogen bond interaction,resulting in the rapid thickening of the hydration layer between H2O and H2O,and the enhancement of HF-HCPs hydration Expansion.In HF-HCPs???H2O???H2O,the interaction energy between H2O???H2O and the two hydroxyl groups of HF-HCPs model molecule is higher than that between H2O???H2O and the combination of hydroxyl and methoxy groups at the same time.The synergistic effect of HF-HCPs?H2O?n clusters was confirmed.With the increase of n,the interaction energy of each unit increases.The end stage of hydration expansion process can be interpreted as:the synergistic effect range of HF???HCPs?H2O?nclusters is limited,and the thickness of hydration layer is limited.Therefore,when the change of En value tends to 0.0k J·mol-1,the polymer network is completely expanded,and the osmotic pressure difference on the network is equal to zero.In this case,the expansion process is terminated.The swelling behavior of HF-HCPs?H2O?n cluster is mainly attributed to the synergistic effect of hydrogen bond interaction between H2O molecules.?3?Pyridine and 2,4-dinitrochlorobenzene were used as model compounds to study the adsorption properties of HF-HCPs.HF-HCPs has a fast adsorption rate for pyridine and2,4-dinitrochlorobenzene,the adsorption equilibrium can be reached within 40 minutes,and the adsorption kinetic process conforms to the PSO kinetic model.Pyridine and2,4-dinitrochlorobenzene can be adsorbed by HF-HCPs in aqueous solution through hydrogen bonding and hydrophobic interaction,and the adsorption isotherm data can be fitted by Langmuir model.The adsorption of 2,4-dinitrochlorobenzene by HF-HCPs in different concentrations of ethanol was investigated,and the role of hydrogen bond in the adsorption process was verified.?4?Using melamine,resorcinol and p-benzenedicaldehyde as raw materials and dimethyl sulfoxide as solvent,hypercrosslinked polymers containing both hydroxyl group and secondary amine group were prepared under hydrothermal conditions.The influence of the ratio of melamine and resorcinol on the specific surface and pore size distribution of polycondensation products was investigated.The increase of the ratio of melamine can increase the specific surface area of products and the amino content of polymer surface.The surface of NH-HCPs contains a large number of hydroxyl and secondary amino groups.The amino group can produce chemical adsorption with salicylic acid,while the hydroxyl group can combine with salicylic acid through hydrogen bond or electrostatic action.The adsorption process is an exothermic spontaneous process. |
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