【作者】 雷光财；

【导师】 戴李宗；

【作者基本信息】 厦门大学 ， 高分子化学与物理， 2008， 硕士

【摘要】 高吸水性树脂（SAR）是一类具有高吸水保水性能的高分子材料,已在医用卫生、农林园艺等众多领域扮演重要角色。理想的SAR应具备高吸水能力、高吸水速率、良好的机械强度;多孔性SAR在吸水能力和吸水速率上具有很大优势,已受到广泛关注。国内对多孔性SAR的研究较少,且主要集中于制备方法上,特别集中于水溶液均相聚合上,对多孔性的形成机理没有具体描述,对孔结构的准确控制还有待深入研究。据此,本论文采用反相悬浮聚合法（ISP）制备丙烯酸系多孔性SAR微球,探索微球多孔结构与性能关系,尝试研究微球多孔结构的形成和控制及其成孔机理。（1）以过硫酸铵（APS）为引发剂、N,N’-亚甲基双丙烯酰胺（NMBA）为交联剂,以甲醇为后处理剂,采用ISP制备出AA-AANa-AM共聚物多孔性SAR微球,并用FT-IR、SEM、EDS进行结构组成分析。分析结果表明,成功制备出多孔性SAR微球,当AM与AA比值为1/2、APS与NMBA用量同时达到单体（AA+AM）量的0.46wt%时,SAR微球的成孔情况最佳;SAR微球的多孔结构均为连通、开孔的结构。研究认为,多孔结构的形成需要:①微球内部结构上的差异,差异越大越有利于孔洞的形成;②外界的诱导作用,利用甲醇等沉淀剂诱发部分溶胀SAR微球体系相转变,致使丙烯酸系SAR微球内部区域非均化,诱导作用越强越有利于多孔结构的形成;③微球结构刚性的强弱:在一定范围内,交联密度越小,微球网络刚性越大,越有利于多孔结构的形成。（2）以PEG为成孔剂,制备丙烯酸系多孔性SAR微球。PEG600作为成孔剂能促进微球多孔结构的形成,当PEG600用量为单体（AA+AM）量的13.33wt%时,SAR微球的成孔情况最佳,为似蜂窝状结构;PEG6000作为成孔剂不利于微球多孔结构的形成。研究认为,成孔剂法制备多孔结构需要:①合适的成孔剂,成孔剂越容易脱除,成孔越好;②合适的脱除剂,SAR微球中成孔剂脱除越完全,成孔越好;③合适的网络稳定剂,成孔剂脱除后所留下的孔洞被固定的越好,成孔越好。甲醇具有稳定丙烯酸系SAR微球网络以及脱除成孔剂的作用,甲醇的使用有利于多孔结构的形成与稳定;同时网络交联度的提高,刚性增大,也有利于网络结构的稳定。本论文所制备的多孔性SAR微球毛细管效应显著、微球浸润速率快,吸收100g/g去离子水所需时间在9s以内,比非孔性SAR微球的吸水速率提高近一个数量级;同时多孔性SAR微球“疏松”程度提高,网络结构得到更好的“梳理”,网络更易舒展,提高了微球内可容纳自由溶液的体积,具有更高的吸液倍率。孔数越多,吸液性能提高的越大。SAR微球经Al³⁺、Ba²⁺或Ca²⁺表面交联后,SAR微球多孔结构不受破坏:表面小孔多且分散、内部大孔多且密集;但SAR微球耐热性能得到较大提高,特别是热分解温度提高100℃以上。更多还原

【Abstract】 Super-absorbent resin （SAR） which can absorb and retain a lot of aqueous liquid has been playing an more important role in many fields, such as medicinal products, hygienic products, agriculture, and forestry horticulture, etc.. Desiring features of SAR should have the capacity of super-absorbent, super-absorbent rate and good strength of the swollen gel. Porous SAR has been considered as an important process in increasing absorbent capacity and absorbent rate. At present, the most study of porous SAR are on synthetical methods, especially on aqueous solution polymerization., but without the study of mechanism and control of pore-forming in domestic research. Therefore, porous SAR micro-spheres were synthesized by inverse suspension polymerization （ISP） in this work and the relationship between porous structure and performance, the formation and control of the pore, the mechanism of pore-forming have already been explored in this work.（1） Ammonium persulfate as an initiator and N,N’-methylene-bis-acrylamide （NMBA） as a crosslinking agent, the porous micro-spheres of AA-AANa-AM copolymer were synthesized by ISP. Then the product was filtered and washed by methanol. The morphology, constitution and micro-spherical structure of the copolymer are characterized with FT-IR, SEM and EDS. It is indicated that the porous SAR micro-sphere has been successfully synthesized. When the mass ratio of AM/AA was 1/2 and the mass ratio of （APS+NMBA）/（AA+AM） was up to 0.46wt%, the porous structure is optimal with connecting and open pore. Exploring the mechanism of the pore-forming, it is indicated that the differences in the mass ratio of AA/AM during the polymerization of copolymer, the outside induction and the rigidity of network are the main factors for formation of the porous structure. The more bigger difference of the copolymer’s structure, the stronger outside induction and the stronger the rigidity of the network, the more number of the pore can be found in the micro-spheres.（2） Acrylate porous SAR micro-spheres were synthesized with PEG as a pore-forming agent. The promotion of pore-forming can be promoted by PEG assisting. When the content is up to 13.33% PEG600 （calculated by the amount of AA+AM）, the alveolate porous morphology appeared and as a pore-forming agent, the PEG6000 has a negative effect on pore-forming. It is shown that some obligations of porosigen technique are inevitable which are facile and removable pore-forming agent, eluate by which pore-forming agent can be washed completely and appropriate network stabilizer which assists porous stabilization. Methanol plays a role as network stabilizer and eluate which fulfills the pore-forming and stabilization. Increasing crosslinking and rigidity of network can improve porous stabilization.The porous SAR micro-spheres which were synthesized in this work have remarkable capillary effect and high soaking rate. The water absorbtion rate is 9s/(100g·g^-1), one order of magnitude faster than that of non-porous SAR micro-sphere. Because of more loosen structure which is easer to be expanded, the porous SAR micro-spheres have higher absorbent capacity. The more number of the pore is, the better absorbent performance the porous SAR micro-spheres have.The structure of SAR micro-spheres which were cross-linked with Al³⁺, Ba²⁺ or Ca²⁺, is still porous, which possessed many disperse small pores on the surface and many dense big pores inside. However, the thermal properties of SAR micro-spheres are highly improved, especially thermal decomposition temperature up to above 100℃.更多还原