聚二乙烯苯型多孔吸附剂的纳米孔结构表征

采用氮气吸附法 ,研究聚二乙烯苯多孔吸附剂的纳米孔结构 .结果表明 ,以甲苯 液体石蜡 (2 :1)为致孔剂制备的聚二乙烯苯多孔吸附剂 ,其比表面和孔体积随致孔剂用量增大而增加 .在二乙烯苯总含量相当时 ,m 二乙烯苯与p 二乙烯苯等比例混合制备的吸附剂 ,具有最大的比表面和孔体积 ,而聚m 二乙烯苯吸附剂和聚p 二乙烯苯吸附剂依次下降 .中孔分布研究说明 ,各种吸附剂的中孔主要分布在 2～ 2 0nm之间 ,其中在5nm附近存在一个明显的分布峰 ,是吸附剂在制备时由于致孔剂的存在而在微核 微核之间形成的孔 .微孔分布研究发现 ,聚m 二乙烯苯吸附剂和聚p 二乙烯苯吸附剂的微孔集中分布在 0 .4～ 1.2nm之间 ,这些微孔可能是微核内部不规整聚集的高分子链之间的缝隙和紧密接触的微核之间的缝隙 .用扫描电镜观察吸附剂内部 ,显示吸附剂的确是由微核聚集形成的 ,其间存在着大小不同的纳米尺度的空隙

CHARACTERIZATION OF THE NANOSCALED PORES IN POROUSPOLYDIVINYLBENZENE ADSORBENTS

The nanoscaled pores in porous polydivinylbenzene beads,prepared by the suspension polymerization of pure divinylbenzene isomers or industrial divinylbenzene in presence of toluene/liquid paraffin (2:1, V/V) as the mixed porogen,were characterized by nitrogen adsorption at 77?K and by scanning electron microscopy.It was found that the specific surface area and total pore volume were enlarged by increase of porogen amount.Among the polydivinylbenzene adsorbents with almost same total content of divinylbenzene monomers,only poly( m divinyl\|benzene co p divinylbenzene) (1∶1) adsorbent,other than poly( m divinylbenzene) or poly( p divinyl\|benzene),possessed the largest specific surface area (726.3?m 2/g) and total pore volume (0.6637?mL/g).From the mesopore size distributions of the polydivinylbenzene adsorbents according to BJH method,it was observed that mesopores were mainly distributed in the diameter range of 2～20?nm and a peak at about 5?nm appeared.The result suggested that it was the mixed porogen to result in such mesopores in the polydivinylbenzene adsorbents.The mesopores could be directly observed on scanning electron micrographs.Micropore size distributions of poly( m divinylbenzene) and poly( p divinylbenzene), calculated on basis of HK method and SF method,revealed that there were lots of micropores in the range of 0.4～1.2?nm.Micropores would be the cavities formed owing to irregular aggregation of highly crosslinked polymeric chains.