【作者】 祁晓华；

【导师】 柳明珠；

【作者基本信息】 兰州大学 ， 高分子化学与物理， 2009， 博士

【摘要】 本学位论文根据高吸水树脂的具体应用要求,结合国内外关于高吸水树脂的最新研究成果,以丙烯酸、异丙烯膦酸和2-丙烯酰胺基-2-甲基-1-丙烷磺酸为聚合单体,以硅藻土、改性高岭土和凹凸棒土为无机添加材料,制备了在生理盐水中常压及加压下吸水率高,吸水速度快,吸水后凝胶强度、分散性、弹性、表面干爽性等性能均好的耐盐性高吸水树脂,并对其溶胀动力学及其在不同电解质溶液中的溶胀行为进行了考察,得到的主要结果有:(1)采用水溶液聚合法,以N,N’-亚甲基双丙烯酰胺为交联剂,以硅藻土和部分中和的丙烯酸为原料,以抗坏血酸-双氧水为氧化还原引发体系,制得了有机-无机复合高吸水性树脂。最佳条件下制得的复合高吸水树脂,在常压下,0.9 wt%NaCl水溶液中的吸水率为99g/g。该树脂具有较快的吸水速度和较好的凝胶强度,且可以重复多次使用。(2)采用水溶液聚合法,以三羟甲基丙烷三缩水甘油醚为交联剂,以羧甲基淀粉改性的高岭土、部分中和的丙烯酸及异丙烯膦酸为原料,以过硫酸铵为引发剂,制得了复合耐盐性高吸水树脂。最佳条件下制得的复合耐盐性高吸水树脂,在常压下,0.9 wt%NaCl水溶液中的吸水率为74g/g。(3)采用水溶液聚合法,以三羟甲基丙烷三缩水甘油醚及N,N’-亚甲基双丙烯酰胺为交联剂,以部分中和的丙烯酸、2-丙烯酰胺基-2-甲基-1-丙烷磺酸为共聚单体,以凹凸棒为无机添加材料,在室温下,以抗坏血酸-双氧水为氧化还原引发体系,采用发泡技术,合成了高吸水树脂,并对该高吸水树脂进行了表面交联,最后再与无机盐共混,制得了具有多孔结构的复合耐盐性高吸水树脂。研究了反应条件对多孔复合高吸水树脂在常压及加压下吸水率和吸水速度的影响。在此基础上,选用正交实验设计方法,同时改变多个影响因素,以常压及加压下,在0.9 wt%NaCl水溶液中吸水率和吸水速度为指标,对合成条件进行了优化。在最佳条件下制备的多孔复合耐盐性高吸水树脂,在0.9 wt%NaCl水溶液中,其常压及加压下吸水率分别为56g/g和9g/g,且吸水速度高达0.493 mL/(g.s)。此外,吸水后的凝胶具有较好的耐盐性、强度、弹性、分散性和表面干爽性。在此基础上,对多孔复合耐盐性高吸水性树脂在不同外界环境中的溶胀行为进行了研究,结果发现:高价阳离子溶液对其溶胀行为影响显著,出现了退溶胀现象;pH值及阴离子对其溶胀行为的影响不如高价阳离子显著;在不含高价阳离子的盐溶液中,由于树脂所具有的多孔结构,表现出supercaseП扩散行为。(4)首次采用电位法测定了高吸水树脂在NaCl溶液中的溶胀动力学。通过理论分析及相关实验,证明了电位法跟踪高吸水树脂在NaCl溶液中溶胀动力学的有效性。根据实验结果,对高吸水树脂在NaCl溶液中的的溶胀机理进行了新的阐述。更多还原

【Abstract】 In this thesis,according to the applications and recent researches on the superabsorbent,a series of superabsorbent composites based on the monomers,acrylic acid,isopropenylphosphonic acid,2-acryloylamino-2-methyl-l-propanesulfonic acid and inorganic materials,diatomite,modified kaolin,attapulgite,were prepared by solution polymerization.On the basis of investigation of the salt-resistant superabsorbent composite synthesis,structure,properties and swelling kinetics,the main results were obtained as follows:（1）A diatomite composite superabsorbent was synthesized by solution polymerization of partially neutralized acrylic acid and diatomite using N,N’-methylenebisacrylamide as a crosslinking agent,and hydrogen peroxide and L-ascorbic acid as a redox initial system.The influences of some reaction conditions,such as diatomite content,neutralization degree of acrylic acid,amount of initiator and crosslinking agent,monomer concentration,and the reaction temperature on swelling characteristic were investigated.The water absorbency of the sample prepared at the optimal conditions was 99 g·g^-1in 0.9 wt%NaCl solution.Moreover,the sample had good swelling rate,hydrogel strength,reswelling ability and water retention.However, the resistance of sample to salt was a little lower than that of polyacrylate.（2）A modified kaolin composite superabsorbent was synthesized by solution polymerization of partially neutralized acrylic acid,isopropenylphosphonic acid（IPPA） and carboxymethyl starch modified kaolin（CMS-kaolin）using trihydroxymethyl propane glycidol ether as a crosslinking agent,and ammonium persulfate as an initiator. The influences of some reaction conditions,such as CMS-kaolin content,neutralization degree of acrylic acid,amount of initiator,amount of crosslinking agent,IPPA content, and the reaction temperature on swelling characteristic were investigated,the water absorbency of the sample prepared at the optimal conditions was 74 g·g^-1in 0.9 wt% NaCl solution. （3）A salt-resistant fast swelling macroporous superabsorbent composite was prepared by copolymerization of partially neutralized acrylic acid, 2-acryloylamino-2-methyl-1-propanesulfonic acid and attapulgite.To enhance the swelling rate of the copolymer,foaming technique was used in the course of copolymerization.Furthermore,for improving the properties of swollen hydrogel,such as strength,resilience and dispersion,the copolymer was surface-crosslinked.And then the surface-crosslinked copolymer was blended with inorganic salt in post treatment process. The influences of some reaction conditions,such as amount of 2-acryloylamino-2-methyl-1-propanesulfonic acid,attapulgite,initiator,N, N’-methylenebisacrylamide,trihydroxymethyl propane glycidol ether,foaming agent, neutralization degree of acrylic acid,and reaction temperature on water absorbency in 0.9 wt%NaCl aqueous solution both under atmospheric pressure and load were investigated. In addition,the effect of them on swelling rate was also studied.After that,an orthogonal design was employed to optimize the reaction conditions.The water absorbency of macroporous superabsorbent composite prepared under optimal conditions in 0.9 wt% NaCl aqueous solution under atmospheric pressure and certain load（P≈2×10³ Pa）were 56 g/g and 9 g/g,respectively,and the swelling rate reached 0.493 mL/（g.s）.The excellent hydrogel strength,resilience and dispersion of swollen hydrogel were also observed.In addition,the effects of pH values,ions and their concentration on swelling behavior of sample were investigated.The results showed that the swelling behavior of sample was affected by pH value.However,the supercase IT diffusion was observed in all NaCl solutions with different pH values.It was found that cations,especially multivalent cations in swelling medium,had significant effect on swelling behavior of sample.An overshooting effect appeared in all solutions containing multivalent cations. For anions,it showed little effect on swelling process,and supercaseΠdiffusion was also observed no matter which anions existed in swelling medium.（4）Open circuit potential measurement was introduced to trace the swelling kinetics of superabsorbent.Based on the results and theoretical analysis,the reliability of open circuit potential measurement in tracing the swelling kinetics of superabsorbent was verified.Moreover,the swelling model for the superabsorbent in salting liquid was slightly modified.更多还原