超交联法制备中空微孔聚合物微球

Preparation of Hollow Microporous Polymer Microspheres by Hypercross-Linked Method

以改性Si O2纳米微球为模板,经乳液聚合在其表面包覆聚苯乙烯-二乙烯基苯(PS-DVB)共聚物壳层,再通过超交联的方法在PS-DVB壳层中形成微孔结构,最后用氢氟酸(HF)除去Si O2内核得到中空微孔聚合物微球(HMPMs)。采用粒度分布仪、红外光谱、透射电镜、比表面积及孔隙分析仪对其形貌和结构进行了表征。结果表明,当DVB含量增加到5%以后,才能获得中心对称的核壳结构Si O2/PS-DVB复合微球;随着DVB含量的增加,中空微孔聚合物的比表面积呈下降趋势,其中DVB含量为0.5%的中空微孔聚合物比表面积达到778.07 m2/g;中空微孔聚合物微球壳层中不仅存在大量微孔,同时存在少量介孔和大孔结构,通过调节DVB的含量在一定程度上可实现对孔结构的调控,这为进一步实现对各种荧光、磁性或药物小分子的负载研究提供了理论依据。

The hollow microporous polymer microspheres（ HMPMs） were synthesized by hypercross-linked method.The fabrication included the copolymerization between styrene（ St） and divinylbenzene（ DVB） via emulsion polymerization on 3-glycidoxypropyltrimethoxy silane（ γ-MPS） grafted silica cores and the formation of microporous channels via Friedel-Crafts reaction. Inorganic cores were removed with HF to obtain the HMPMs. The morphology and structure were characterized by particle size analyzer,FT-IR spectroscopy,TEM,specific surface area and porosity analyzer. The Si O2/ PS-DVB composite microspheres with central symmetrical core-shell structure can be obtained only when the content of DVB reaches or exceeds 5%; The BET surface area decreases with the increasing DVB content. The as-prepared HMPMs＇ BET surface area can be as high as 778. 07 m2/ g when the DVB content is 0. 5%. The hollow cross-linked polymer shell combines massive microporous and a certain amount of mesoporous and macroporous features in one unit.The pore size is found to be tunable by changing DVB content to a certain extent. This provides a theoretical basis for further implementation of loading various fluorescent,magnetic or small drug molecules into HMPMs.