【作者】 崔亦华；

【导师】 崔英德；

【作者基本信息】 广东工业大学 ， 功能高分子材料， 2008， 博士

【摘要】 高吸水性树脂（SAP）作为一种功能性高分子材料,由于其特有的高吸水性和保水性,已经在各个领域得到日益广泛的应用。国内外对高吸水性树脂的研究主要集中在合成方法和反应机理等方面,但考虑到环境保护和经济可持续发展,对使用高吸水性树脂造成的环境影响和其生物降解性的研究也逐渐被提上日程,已有不少研究机构做了这方面的工作。目前市场上使用的高吸水性树脂几乎都是聚丙烯酸（简写为AA）类,但其生物分解性差,易造成地下水及土壤环境污染,可生物降解高吸水性树脂的制备引起了学术界极大的关注。本文通过分子设计,首先合成了一种乙烯基含氧杂环化合物2-亚甲基-1,3-二氧杂环庚烷（简写为MDO）,然后以这种乙烯基含氧杂环化合物MDO和丙烯酸为单体,通过开环共聚与交联反应,合成了主链上含有C-O-C醚键的可生物降解高吸水性树脂,并通过互穿网络结构的设计,改善了高吸水性树脂的机械强度和耐盐性。采用FTIR、¹H-NMR、13C-NMR、SEM、DSC等分析测试方法表征了MDO及所设计合成的新型高吸水性树脂的分子结构,研究了高吸水性树脂的溶胀性能和生物降解性能。具体研究内容及结果如下:以氯乙醛缩二甲醇和1,4-丁二醇为原料,D001型大孔离子交换树脂作为固体酸性催化剂,通过缩合反应制得中间产物2-氯亚甲基-1,3-二氧环庚烷（Cl-MDO）,Cl-MDO再经脱氯反应制得MDO,考察并优化了合成工艺条件,其中:制备Cl-MDO的最优工艺条件为:原料配比n_CDA:n_BDO为1:1.15,D001型离子交换树脂酸性催化剂的质量含量为1%,反应温度为115℃,当甲醇的收集量达到理论计算量时,反应结束。产物经减压蒸馏后得Cl-MDO,Cl-MDO的收率为95%以上。优化的MDO的合成条件为:原料配比n_（BuOK）:n_（Cl-MDO）:1.20:1.0,醇溶液摩尔比n_（BuOH）:n_（BuOK）=1.20:1.0,在105℃的温度下反应5h,再经减压蒸馏后得到收率为70%的MDO产物。分别采用静置溶液聚合法和反相悬浮聚合法,将AA与MDO进行开环交联共聚,制备主链上含有C-O-C醚键的P（AA/MDO）可生物降解高吸水性树脂。对两种聚合工艺进行了优化,结果如下:静态溶液聚合法以过硫酸钾为引发剂。N,N’-亚甲基双丙烯酰胺为交联剂,四丁基溴化氨为相催化剂。MDO质量含量为8%,引发剂质量含量为0.15%,交联剂质量含量为0.2%,相催化剂质量含量为2%,AA中和度为85%,单体浓度为30%,反应温度为75℃和反应时间为2h。在此条件下制备的高吸水性树脂吸水率和吸盐水率可分别达350g/g和82g/g。反相悬浮聚合法采用偶氮二异丁氰为引发剂,N,N-亚甲基双丙烯酰胺为交联剂。环己烷为溶剂,Span60为分散剂,四丁基溴化铵为相催化剂,优化的工艺条件为:MDO质量含量为8%,油水质量比为5.5:1,引发剂质量含量为0.3%,交联剂质量含量为0.2%,AA中和度为85%,分散剂质量含量为5.5%、相转移催化剂质量含量为3%,在反应温度为75℃条件下反应2h,在此条件下制备的高吸水性树脂吸水率和吸盐水率可分别达520g/g和85g/g。为了提高P（AA/MDO）高吸水性树脂的机械强度和耐盐性,采用反相悬浮聚合法制备了PEG-SIPN-P（AA/MDO）半互穿网络结构高吸水性树脂。研究了聚乙二醇（PEG）分子量和质量含量对PEG-SPIN-P（AA/MDO）吸液性能的影响。PEG是非离子直链型聚合物,通过PEG与P（AA/MDO）之间的氢键和相互缠绕作用,能明显提高高吸水性树脂的机械强度和耐盐性,而且当PEG4000的质量含量为4%时,SIPN型高吸水性树脂吸液性能最好,其中吸水率为506g/g。而吸盐水率由85g/g提高到98g/g。研究了MDO单体和互穿体PEG对高吸水性树脂溶胀性能的影响。由于MDO带有支链结构,而且MDO开环后带有羰基,提高了高吸水性树脂的吸液率和吸水速率,同时也降低了高吸水性树脂的脱水速率下降,即提高了保水性。当PEG4000的质量含量为4%时,形成的SIPN型高吸水性树脂机械强度适中,耐盐性能最好,吸水速率也最快。文中还研究了MDO和PEG对高吸水性树脂的溶胀温度效应的影响。采用琼脂板培养法和二氧化碳生成量（PCD）法研究了MDO单体对高吸水性树脂的生物降解性的影响。结果表明:由于引入了MDO单体,微生物枯草杆菌和黑曲霉均能在高吸水性树脂上生长,证明所设计、合成的P（AA/MDO）高吸水性树脂主链上含有C-O-C醚键,是可生物降解聚合物。而且P（AA/MOD）型高吸水性树脂的生物降解速率可以由其主链结构设计决定:MDO质量含量越大,主链上含有C-O-C醚键越多,高吸水性树脂生物降解速率越快:MDO质量含量越小,则降解速率越慢,而且反相悬浮聚合法所合成的高吸水性树脂的降解性能优于静态溶液聚合法。更多还原

【Abstract】 Super-absorbent polymer （SAP）, a functional macromolecular material, possesses excellent properties such as water-absorption, water-retention, etc. SAP has been widely used in many fields. Many studies have been carried out about the synthetic method and reaction mechanism. For the purpose of environmental protection and economic continuous development, this project focuses on the biodegradability of SAP based on acrylic acid （AA）, because AA is the common monomer for the synthesis of SAP, and SAP based on AA is weakly biodegradable and will pollute underground water and soil.In this paper, a cyclic ketene acetal of 2-methylene-1,3-dioxepane （MDO） was prepared. And then biodegradable SAP with C-O-C in the backbone was synthesized by Ring-Opening copolymerization of MDO with acrylic acid （or acrylate）. To improve the strength and anti-saline property, PEG was introduced into the SAP to give interpenetrated networks. During the study, structures of the intermediates, namely 2-Chloromethyl-1,3-Dioxepane（Cl-MDO）, MDO, and biodegradable SAP were characterized with FT-IR, ¹H-NMR, ¹³C-NMR, SEM, and DSC. The swelling property of the biodegradable SAP was studied as well. The detailed contents of this paper are as follows:2-Methylene-l,3-dioxepane can be synthesized by a two-step reaction. At first, an intermediate C1-MD0 was synthesized by condensation reaction of chloroacetaldehyde dimethyl acetal with 1,4-Butanediol （BDO） over D001 Ion Exchange Resin. Secondly, MDO was synthesized by reaction of C1-MD0 with potassium t-butoxode by using t-butyl alcohol as solvent. The optimized technological conditions were investigated, and the results are as follows:Cl-MDO was synthesized with: n_CDA: N_BDO as 1: 1.15, the mass content of D001 Ion Exchange Resin was 1%, the reaction temperature was 115℃. When the calculated amount of methanol has been collected, the crude product is fractionally distilled to produce Cl-MDO. The yield was over 95%.MDO was synthesized with: n_（BuOK）:n_（Cl-MDO）= 1.20:1.0 and n_（BuOH）:n_（BuOK）= 1.20:1.0. The reaction temperature was 105℃. After 5h the crude product was fractionally distilled to produce MDO. The yield was over 70%.Biodegradable SAP with C-O-C in the backbone was synthesized by the Ring-Opening copolymerization of MDO with acrylic acid （or acrylate） by solution polymerization and suspension polymerization. The two methods are as follows:Biodegradable SAP was synthesized by Ring-Opening copolymerization of MDO with acrylic acid （or acrylate） by means of solution polymerization. The reaction was initiated by potassium persulfate and crosslinked by N,N’-methylenebisacrylamide with tetrabutylammonium bromide （TBAB） as catalyst. The optimized technological conditions were the mass content of MDO 8%, the mass content of initiator 0.15%, the mass content of catalyst 2%, the neutralization degree of acrylic acid 85%, the monomer concentration 30%, the reaction temperature 75℃, the time of reaction 2h. The best absorbability of in salt free water was 350g/g and 82g/g in 0.9% NaCl solution.Biodegradable SAP was also synthesized by Ring-Opening copolymerization of MDO with acrylic acid （or acrylate） by means of suspension polymerization. The reaction was initiated by AIBN and crosslinked by N,N’-methylenebisacrylamide with cyclohexane as solvent, SP-60 as dispersant and TBAB as catalyst. The optimized technological conditions were the mass content of MDO 8%, the mass ratio of cyclohexane, asdispersed phase, to water was 5.5:1, the mass content of initiator and crosslinking agent were 0.3% and 0.2% respectively, the neutralization degree of acrylic acid 85%, the mass content of dispersant 5.5%, the mass content of catalyst 3%, the reaction temperature 75℃and the reaction time 2h.The best absorbability of the SAP in salt free water was 520g/g and 85g/g in 0.9% NaCl solution.To improve the properties of strength and anti-saline, the biodegradable SAP of polyethylene （PEG）-Semi-IPN-P（AA/MDO） was synthesized by means of suspension polymerization. The effect of the molecular weight and mass content of PEG on the absorbability of PEG-Semi-IPN-P（AA/MDO） was studied. The results showed that PEG can improve the properties of strength and anti-saline of the biodegradable SAP effectively. The best absorbability of the SAP in salt free water was 510g/g, and the absorbability in 0.9% NaCl solution was improved from 85g/g to 98g/g when the mass of PEG4000 was 4%.The effect of MDO and PEG on the swelling property of the SAP was studied. The absorbability and the swelling rate of P（AA/MDO） increased because of MDO, while the dehydration rate decreased. The strength was suitable, the swelling property and anti-saline of PEG-SIPN-P（AA/MDO） were the best when the mass of PEG4000 was 4%. In this paper, the effect of MDO and PEG on the response of the SAP to swelling temperature was studied.At last, the effect of MDO on the biodegradability of P（AA/MDO） was studied by the method of agar flat analysis and the amount of CO₂ released by the SAP. The results showed that bacillus subtilis and aspergillus nigers can grow on the biodegradability SAP of P（AA/MDO）; P（AA/MDO） with C-O-C in the backbone and they were biodegradable. The biodegradation behaviors of P（AA/MDO） were related to its backbone structure. The biodegradability can be improved as the mass of MDO increase with more C-O-C on the backbone. The biodegradability will become worse as the mass of MDO decreased. The sample prepared with the inverse suspension polymerization is easier to degrade than that prepared with the solution polymerization.更多还原