【作者】 司丽春；

【导师】 王治强； 王戈；

【作者基本信息】 北京化工大学 ， 高分子化学与物理， 2004， 硕士

【摘要】 本论文利用水滑石类层状化合物(LDHs)结构上的诸多优点,如离子交换性、主体层板组分和层板电荷密度可调、制备方法多样、晶粒尺寸及其分布可控等,对LDHs为模板制备纳米聚合物进行研究。具体设计思想如下:将单体插层组装到LDHs层间,并使其在层间发生原位聚合反应,而后利用层板的碱性,选用适当的酸溶解水滑石层板以释放出层间聚合物或利用LDHs的离子交换性能将层间生成的聚合物交换出来,达到分离纯化在模板中生成的纳米聚合物的目的。取得的研究成果如下:用共沉淀法制备了晶相单一,结晶性较好的4-乙烯基苯磺酸插层水滑石(SS-LDHs),根据产物的层间距和单体的范德华半径可知,该单体在水滑石层间呈双层倾斜排列。SS-LDHs在150℃下反应,经NMR和UV-Vis的表征可知,层间单体全部发生了聚合,得到聚4-乙烯基苯磺酸插层水滑石(PSS-LDHs)。通过XRD对单体在层间的聚合反应进行了原位跟踪,实验结果表明,单体在层间开始聚合反应后,层间距随反应的进行而变大。在冰浴下用乙酸酐溶解PSS-LDHs层板,可以得到层间聚合物PSS的沉淀,用乙醚洗涤过量的乙酸酐,可以得到纯净的PSS。 TEM和AFM的测试结果显示PSS为片状结构,尺寸在100nm以<WP=4>下,厚度为8-10nm。以Mg2Al-CO3-LDHs为前体,用离子交换的方法不能制备丙烯酸插层水滑石AA-LDHs。但以Mg2Al-NO3-LDHs为前体,用丙烯酸钠溶液进行离子交换反应,可以得到层状结构保持良好的AA-LDHs。以K2S2O8为引发剂,可以引发单体在层间的聚合反应,得到聚丙烯酸插层水滑石PAA-LDHs。用Na2CO3对PAA-LDHs进行第二次离子交换反应,可以将层间的PAA交换到层外,以丙酮为沉淀剂可以得到纯净的PAA产物。分离得到的PAA为结晶聚合物,结构单元呈周期性排列,但存在一定的晶格缺陷。PAA的TEM照片表明,该聚合物为片状结构,尺寸在100nm以下。更多还原

【Abstract】 Layered double hydroxides are a type of materials with lamellar structure. They have some charming properties such as ion-exchange, tunable charge density of layers, large variety of compositions, versatile preparation methods, and diversity of particle size and particle size distribution. Therefore they are perfect candidate as template to prepare nano-polymers. In detail, the reaction system is firstly defined as the assembly of two components, a monomer and a bi-dimensional material LDH as the template. The subsequent in situ polymerization occurs in the interlayer region of the template. Finally the template layers are dissolved by acid so that the produced polymers are free and collected. Another method is exchanging polymer in interlays using anion exchange property of LDHs.The monomer intercalated product SS-LDHs was prepared by coprecipitation method. Given the gallery height determined by XRD analysis of SS-LDHs and the monomer’s covalent radius, we suggest a bilayer arrangement for the intercalated SS anion in interlays of LDHs. The obtained SS-LDHs was heated at 150oC to afford the polymerization of the intercalated monomer, then the polymer intercalated product PSS-LDHs was gained. The gallery height of PSS-LDHs increased following reaction time by XRD analysis. Acetic anhydride can dissolve the layers and precipitate the polymers as well under lower temperature. TEM and AFM micrograph of finely grounded PSS samples reveals that the diameters of the produced polymers are less 100 nm and the thickness 8-10nm. Mg2Al-CO3-LDHs and Mg2Al-NO3-LDHs were allowed to react with acrylate anions in order to prepare the monomer intercalated product AA-LDHs by anion <WP=6>exchange. When Mg2Al-CO3-LDHs was used the anion exchange reaction did not accur. When Mg2Al-NO3-LDHs was employed the reaction proceeded to form a AA-LDHs intercalation compound. The interlayer acryiate anions were polymerized to form a polymer intercalation product PAA-LDHs with initiator K2S2O8. PAA formed in the interlayer of LDHs was exchanged by Na2CO3 with second anion exchange reaction. The finely grounded PAA was crystal polymer and its structure unit arranged periodicity with a little crystal lattice disfigurement. TEM micrograph of PAA samples suggested less 100 nm diameters and plate morphology.更多还原