【作者】 陈展云；

【导师】 蒋林斌；

【作者基本信息】 广西大学 ， 有机化学， 2008， 硕士

【摘要】 超强吸水树脂是一种轻度交联的聚合物,它能吸收和保持高于自身重量几百倍以上的水分。本论文主要采用反相乳液聚合方法,以木薯淀粉为主要原料,N,N′-亚甲基双丙烯酰胺为交联剂,分别以过硫酸钾、高锰酸钾、过氧化氢-亚硫酸钠为引发剂通过接枝共聚反应合成淀粉-丙烯酸接枝共聚物,考察了乳液浓度、单体用量、交联剂用量、引发剂用量、反应温度和丙烯酸中和度对树脂吸水性能的影响。并通过红外光谱、X-射线衍射、热重分析等方法表征接技产物结构。具体内容如下:一、研究了木薯淀粉与丙烯酸接枝共聚物的制备,试验了高锰酸钾、过硫酸钾及过氧化氢-亚硫酸钠三种引发剂的引发效果,实验结果表明高锰酸钾的引发效果最佳;并考察了以高锰酸钾为引发剂时,乳液浓度、单体用量、交联剂用量、引发剂用量、反应温度和丙烯酸中和度对吸水树脂吸水率的影响。实验结果表明最佳接枝工艺条件为:淀粉乳浓度1.11%,单体与淀粉的质量比10:1,引发剂和交联剂用量分别为6.3 mmol·L^-1和9.0 mmol·L^-1,反应温度为50℃,丙烯酸中和度为50%;该条件下的接枝产物对去离子水的吸收可达1600余倍,对自来水的吸收可达380倍。二、采用红外光谱（IR）、差示扫描量热法（TG-DSC）、扫描电镜（SEM）和X-射线衍射（XRD）等方法对产物的结构进行了表征。结果表明:红外光谱分析证明产物具有羰基的特征吸收;热分析图谱表明产物比淀粉具有更高的热稳定性;X-射线衍射证明有木薯淀粉的半晶体结构变为无定形态;扫描电镜图谱表明木薯淀粉表面被丙烯酸破坏。以上表征证明在木薯淀粉链上接枝上丙烯酸。三、对接枝制备的超强吸水树脂的吸水速率、保水能力、热稳定性、抗盐性、恢复性等性能进行了实验,实验结果如下:（1）实验证明超强吸水树脂保水性能非常优越。（2）超强吸水树脂在蒸馏水中的吸液速率相当快,吸液后150min达到饱和,这表明吸水树脂在蒸馏水中的吸液速率比较快。（3）在电解质溶液中,随着电解质浓度的增加,树脂吸水性能下降,对于相同浓度的电解质溶液,金属离子所带电荷数越大,树脂的吸收性能越低。（4）超强吸水树脂对有机溶剂几乎不具有吸液能力,但在一定浓度范围内的有机水溶液中具有一定的吸液能力,并出现吸液临界点。（5）超强吸水树脂具有良好的重复使用能力。（6）超强吸水树脂的吸收性能受温度的影响较小,可以在较宽温度范围内使用。（7）树脂在中性范围内使用,能发挥较高吸水性能,而在强酸性或强碱性条件下,吸水性能下降。更多还原

【Abstract】 Super absorbent resins （SAR） are lightly crosslinking hydrophilic polymers that can absorb and retain aqueous solutions up to hundreds of times their own weight. In this paper, a graft copolymer was synthesized by copolymerization of acrylic acid （AA） onto cassava starch, with N,N’-methylene diacrylamide as cosslinking agent, potassium persulfate potassium permanganate and hydrogen peroxide-sodium sulfite as an initiator. The effects of the amount of crosslinking agent, monomer, initiator, the reaction temperature, neutralization degree of acrylic acid, the mass ratio of AA/starch and concentration of starch emulsion were studied. The grafting copolymerization was analysed by FT-IR, XRD and TG.-DSC.Three initiation systems, potassium permanganate, potassium persulfate and hydrogen peroxide-sodium sulfite were used to initiate the graft polymerization of acrylic acid （AA） onto cassava starch. The initiating effects were investigated, and the results showed that the potassium permanganate was the best initiator for this reaction. Initiating with potassium permanganate, the influences of the amount of crosslinking agent, monomer, initiator, the reaction temperature, neutralization degree of acrylic acid, the ratio of AA/starch and concentration of starch emulsion were studied. Such a condition was optimized, as concentration of starch emulsion 1.11%, mass ratio of monomer to starch 10:1, 9.0mmol·L^-1 crosslinking agent and 6.3mmol·L^-1 initiator, 50% neutralization degree of acrylic acid and reaction tmperature 50℃respectively. Under the condition, graft polymerizations of acrylic acid （AA） with cassava starch were done. The absorption rate of the resin was up to 1600 g/g in distilled water, 380 g/g in tap water. The surface sturcture and heat property were analyzed by IR, SEM, TG-DSC, etc. The analysis of IR showed that the synthesized product had carbonyl’s character, which proved graft polymerizations of acrylic acid （AA） with cassava starch. TG-DSC analysis indicated that the products had good thermostability. X-RAY showed that the surface structure of starch became amorphous from semi-crystalline. SEM analysis showed that the surface of starch was destroyed by acrylic acid （AA）.In the last paper, the evaluations of some influential factors such as retention ability, absorption rate, recovery ability, stability and anti-saltability are researched, and some important conclusions were drawn:（1） The results had shown that the SAR had water retention ability and a satisfied stability.（2） The absorption rate of SAR in distilled water was fast and achieved saturating in the first 150 min respectively.（3） The SAR in electrolyte solution declined with the increase of metal cationic charge and the concentration of solution.（4） The SAR nearly had no absorbency in pure organic solvents, but it had one in the mixture of organic solvents（o） and water（w） with a special volume ratio Vo:Vw and appeared a critical point in specific mixture of organic solvents（o） and water（w） with a special volume ratio Vo:Vw.（5） The results had shown the SAR had outstanding recovery properties.（6） The effect of temperature on the absorbency of SAR was weak, and the SAR was used in a large temperature range.（7） The SAR absorbed more in neutral solutions than in acidic or alkli solutions.更多还原