原位插层聚合制备聚丁二烯/蒙脱土纳米复合材料及其结构与性能研究

采用负离子引发原位插层聚合法制备了聚丁二烯(PB)/有机蒙脱土(OMMT)纳米复合材料(NC).对OMMT纯化方法、OMMT种类和溶剂等因素对聚合反应的影响进行了研究.不同方法纯化的OMMT消耗的BuLi量相差一倍;采用OMMT-DK1制备的NC具有较宽的分子量分布,而采用OMMT-DK1B和OMMT-DK4制备的NC则具有较窄的分子量分布;OMMT在环己烷中不溶解,在甲苯和二甲苯等溶剂中可形成均匀溶液.采用XRD、TEM和H-NMR等仪器对PB/OMMT NC的插层结构、化学结构和形态进行了分析;采用DSC、TGA和DMA等仪器对PB/OMMT NC的Tg、热学性能和动态力学性能进行了研究,结果表明,采用负离子原位插层聚合可得到剥离型PB/OMMT纳米复合材料;与OMMT插层复合明显改变了PB的微观结构组成,在OMMT含量为6.2wt%时,1,2-结构含量增加了近一倍,Tg和Tdc分别增加了10 K和16 K;E′、E″均明显提高,而tanδ下降.

STUDIES ON PREPARATION OF POLYBUTADIENE/MONTMORILLONITE NANOCOMPOSITES BY ANIONIC POLYMERIZATION AND THEIR STRUCTURE AND PROPERTIES

Polybutadiene/montmorillonite nanocomposites(NC) were prepared by in situ anionic polymerization.The effects of treating method of OMMT,the kinds of OMMT and solvent on polymerization were studied.The structure and properties of the nanocomposites were characterized by using XRD,TEM,HNMR,DSC,TGA and DMA.A two times change of Buli wastage was found for OMMTs treated by different methods.The NCs had wide molecular weight distribution,when OMMT-DKI was added,whereas the NCs had narrow molecular weight distribution when OMMT-DK1B and OMMT-DK4 were added.The OMMT was soluble in toluene and xylene,but didn't dissolve in cyclohexane.XRD and TEM showed that the exfoliated nanocomposites were prepared by the in situ anionic polymerization.From the H-NMR spectra of polybutadiene(PB) and PB/OMMT nanocomposites,microstucture changes of PB were found.The 1,2 unit content of PB increased approximately 100%,when 6.2 wt% of OMMT was added.The results of DSC and DMA indicated that T_g and T_(dc) were increased approximately 10 K and 16 K,respectively,when 6.2 wt% of OMMT was added.Both the storage and loss moduli increased with OMMT addition,and tanδ values decreased.