PVA类高吸水性树脂的制备

以PVA为原料,用顺丁烯二酸酐作交联剂制得了PVA类高吸水性树脂.研究了交联剂用量、反应温度、PVA聚合度以及处理产物的溶液pH值对树脂吸水率的影响.得到的最佳制备条件为:ω(顺丁烯二酸酐/PVA)为30%,反应温度在98～105℃,所用PVA的聚合度为1700,处理产物的溶液pH值为10左右.     

十二钨钴酸钾的动力学测定

十二钨钴酸钾具有四面体结构,其中金属离子是配合物的中心原子,作为配体的多酸阴离子(W3O10)在四面体顶角,它们具有Keggin结构。本实验用紫外可见光谱测定法,以287nm为测定波长,测定浓度为8 0×10-4mol/L的K5CoW12O40溶液与浓度分别为4 0×10-3、6 0×10-3、8 0×10-3mol/L、12×10-3mol/L的NaNO2溶液进行氧化还原反应时的吸光度。以不同浓度时的ln(A—A∞)对t作图呈线形关系,确定氧化剂反应级数为一。以不同的kobs对还原剂浓度作图,其图形也呈直线,确定还原剂的反应级数也为一,其反应的速率常数K=0 21×103(min-1)。说明K5CoW12O40的氧化还原反应机理是外界反应机理。此法在杂多酸化学中有着重要的意义。     

温度对二氧化氯膜分离及测定的影响

溶液温度对二氧化氯的膜分离效果及流动注射分析(FIA)的准确度、精密度肯定有一定的影响.文章讨论了温度对二氧化氯膜渗透、扩散和气、液相分离效果[1]的影响,从而确定了二氧化氯膜分离及流动注射分析(FIA)的最佳实验温度(20℃).     

复合酶法优化木薯微孔淀粉的工艺及吸附性研究

为优化木薯微孔淀粉的制备工艺,提高吸附性能,采用复合酶法对木薯淀粉进行处理.借助L9(34)正交实验,研究复合酶的用量、pH值、反应温度和反应时间对微孔淀粉吸附性的影响.实验得出:与木薯淀粉对亚甲基兰溶液、食用油的吸附性能相比,微孔淀粉的吸附性能明显提高.最佳工艺条件是:酶用量2.0%,pH值5.5,温度50℃,反应时间36 h.     

丙烯酰胺与长链季铵盐共聚树脂的制备与性能

采用长链烷基烯丙基二甲基氯化铵(RADM)和丙烯酰胺为原料,过硫酸钾为引发剂,N,N′ 亚甲基双丙烯酰胺为交联剂,水溶液聚合法制备了高吸水性树脂,并对最佳反应条件进行了研究。得到最佳条件:x(交联剂)=0 2%、x(RADM)=1 5%～2 5%、n(引发剂)∶n(总单体)=1∶2000、反应温度70℃、反应时间4h。在此条件下制备的共聚树脂在室温吸去离子水达自身质量的535倍,吸w(NaCl)=0 9%的盐水溶液达63倍;树脂溶胀平衡后在106Pa的压力下的保水率大于80%;树脂在溶胀后分别与含金黄色葡萄球菌和大肠杆菌的含菌液接触8h,抗菌率大于75%。     

Superabsorbent polymeric materials. XIII. Effect of oxyethylene chain length on water absorbency for the sodium acrylate and poly(ethylene glycol) methyl ether acrylate (PEGMEAn) copolymeric gels

In a previous study, we prepared a series of xerogels based on sodium acrylate (NaA) and 2‐hydroxyethyl methacrylate (HEMA, OE = 1) or poly(ethylene glycol) methacrylate (PEGMA, OE = 6) with different oxyethylene (OE) units. The effect of the contents of HEMA and PEGMA in the copolymeric gel on the swelling behavior in deionized water and various saline solutions was studied. Their results showed that the water absorbencies for these two series gels were effectively improved by adding a small amount of HEMA or PEGMA. In this article, a series of novel xerogels based on NaA and hydrophilic monomer poly(ethylene glycol) methyl ether acrylate (PEGMEA_n), which was synthesized from acryloyl chloride and poly(ethylene glycol) monomethyl ether with three oxyethylene (OE = 9, 16, 45) chain lengths, were prepared by inverse suspension polymerization. The effects of OE chain length in the copolymeric gel on the water absorption behavior and initial absorption rate for the present xerogels were investigated. Results showed that adding a small amount of PEGMEA_n could effectively increase the water absorbency of the gels. In addition, the water absorbency decreased with an increase of the OE chain length in PEGMEA_n. The initial absorption rate for the present copolymeric gels increased with increasing OE chain length in PEGMEA_n and the content of PEGMEA_n in the copolymeric gels. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 927–934, 2006     

Synthesis of poly(acrylic acid)/sodium humate superabsorbent composite for agricultural use

A novel poly (acrylic acid)/sodium humate superabsorbent composite was synthesized by graft copolymerization reaction of acrylic acid (AA) on sodium humate micropowder using N,N′‐methylenebisacrylamide (MBA) as a crosslinker and potassium peroxydisulfate (KPS) as an initiator in aqueous solution. The effects on water absorbency of factors such as reaction temperature, initial monomer concentration, and degree of neutralization of AA, amount of crosslinker, initiator, and sodium humate were investigated. The superabsorbent composite was characterized by scanning electron microscopy, and the graft copolymerization reaction of AA on sodium humate micropowder was characterized by IR spectroscopy. Results obtained from this study show that the water absorbency of the superabsorbent composite synthesized under optimal conditions for synthesis with a sodium humate content of 5.3% exhibited absorption of 684 g H₂O/g sample in distilled water. Water‐retention in soil is enhanced by the use of the superabsorbent composite. The effect of superabsorbent composite on the growth of corn is reported. The superabsorbent composite may be of use as water management materials for agriculture purposes in desert and drought‐prone areas. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5137–5143, 2006     

织物结构改变对吸湿排汗性能的影响

从纤维类别、织物紧密度、织物组织等因素的改变来改善织物的吸湿透汽性。主要选用天然纤维中的棉和化纤中的二维中空涤纶、普通圆截面涤纶、纳米竹碳涤纶,采用纯纺或混纺方式,以不同紧度和平纹、2/2斜纹、透孔、六枚变则缎纹4种组织织成织物。采用正交试验和极差分析方法,对16种不同织物的吸水高度和透湿量进行检测,找出最主要影响因素。结果表明,织物的原料成分是影响吸湿排汗性的最主要因素,中空涤纶与棉混纺织物比普通涤棉混纺织物的吸水度高276.5%,透湿量高75%。     

Combined Bioscouring and Bleaching of Cotton Fibres

SUMMARY

Cotton fibres were scoured with acid and alkaline pectinases and bleached with peracetic acid. Because of similar treatment conditions of both processes, they were combined in one bath as one-step and two-step processes. At the beginning of the treatments, pH 5 was set for acid pectinases and pH 8 for alkaline pectinases. To activate the peracetic acid, pH was also adjusted during the process. Tetrasodium pyrophosphate was added to improve the effects of bleaching and scouring. The highest CIE whiteness values and water absorbencies were obtained in a one-step process with alkaline pectinases and peracetic acid.     

Cellulose mercerization: Use of amino acid‐glycerol ethers as wetting agents

The action of a new nonconventional series of (tryptophan‐phenylalanine‐histidine and tyrosine)‐glycerol‐ether surfactants as wetting agents in hot cotton mercerization was studied. The mercerization result was evaluated with the barium hydroxide absorption number, water absorbency and moisture regain, and mechanical properties of fibers; the dyeability of the mercerized samples with a direct and reactive dye was also studied. An improvement was observed for all the above parameters in the presence of the aforementioned wetting agents despite their being used in very low concentrations. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009