共查询到20条相似文献,搜索用时 156 毫秒
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高吸水树脂(保水剂)在植物栽培上的应用高吸水树脂是一种新型高分子合成材料,它的特点是能迅速吸收比自身重数百倍的水。吸水性强,保水性也强,它所吸人的水分用压力是不能压出来的,只能慢慢释放出来,而且它在土壤中形成团粒结构,使土壤透水性、透气性增强,同时也... 相似文献
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高吸水树脂是一种近年来迅速发展起来的新型特殊功能高分子材料。它具有奇特的吸水能力和保水能力,在与接触的很短时间内,就可膨润成水凝胶,吸收其自身重量数百倍以至数千倍的水。这是以往使用的吸水材料所不可比拟的。据文献资料表明:高吸水树脂因其组成不同,吸水倍数也高低不 相似文献
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木质材料表面粗糙度光学付立叶测量方法的研究 总被引:2,自引:0,他引:2
阐述了木质材料表面粗糙度现有的测量技术与研究现状,研究了木质材料表面的统计模型和一维高斯型木质材料表面光学付立叶变换谱强度分布的模型,并得到了计算木质材料表面粗糙度均方根误差和自相关函数的数学公式。测量两个参数的实验系统,将具有非接触、高测量速度、测量不受被测材料影响和能得到比较多的轮廓信息等优点,进一步完善后,可用于木质材料表面粗糙度的分类检测及监控。 相似文献
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Dissolution and homogeneous graft copolymerization of cellulose were performed in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) with 2-hydroxyethyl methacrylate. The synthesized AmimCl and cellulose graft copolymers were characterized by FTIR, 1 H-NMR and XRD spectroscopy. The results show that AmimCl dissolved cellulose directly by destroying intermolecular and intramolecular hydrogen bonds in cellulose and the crystalline form of cellulose was transformed from cellulose I to cellulose II after regeneration from AmimCl. The best synthetic condition of the cellulose-graft-P (2-hydroxyethyl methacrylate) was that cellulose 0.5 g, 2-hydroxyethyl methacrylate 3.00 g and initiator ammonium persulfate 0.05 g reacted for 180 min at 60°C; the rate of grafting reached 77.3%. 相似文献
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Mariko Yoshioka Kazuhisa Sakaguchi Takashi Ohno Yoshiyuki Nishio Nobuo Shiraishi 《Journal of Wood Science》2009,55(5):335-343
Cellulose powders were pulverized by an ultra high-pressure counter-collision treatment in an aqueous suspension state, and
then used in composites with vinyl polymers and graft copolymerized with methyl methacrylate using ceric ion initiator. The
influence of freeze-drying methods after microfibrillation of cellulose was visualized by scanning electron microscopy (SEM).
The coalescence of microfibrillar structures was observed to increase easily reflecting the freeze-drying conditions. While
the degree of microfibrillation was unsatisfactory for use as fillers in preparing polymer-nanocellulose composites, the situation
was found to be rectified with the use of a proper kneading technique. The roles of microfibrillated cellulose in processes
producing bio-nano-composites suitable for practical uses were studied through SEM observations and measurements of physical
properties. The characteristics of the successive graft copolymerization were studied through examining the monomer conversion
and the grafting effi- ciency. The significant improvement in the grafting became apparent in response to the counter-collision
pretreatment. Dynamic viscoelastic properties of the molded sheets of the grafted products were studied to measure the effects
of the graft copolymerization compared with the corresponding physically blended material and neat poly(methyl methacrylate).
The grafting reaction resulted in composites with much higher heat-resisting properties than those obtained for the latter
two. 相似文献
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采用Fe2+-H2O2二氧化硫脲(TD)氧化还原体系引发甲基丙烯酸缩水甘油酯(GMA)与桉树漂白木浆接枝共聚,并通过交联制得吸油功能材料——GMA接枝纤维.研究了各因素对接枝纤维接枝率及吸油率的影响红外图谱证明GMA已成功接枝到纤维素上.结果表明:当反应温度55℃,单体浓度0.14 mol/L,H2O2质量浓度0.20... 相似文献
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Fe2+-H2O2-二氧化硫脲引发桉木浆与甲基丙烯酸缩水甘油酯接枝共聚的研究 总被引:1,自引:1,他引:0
研究了Fe2 -H2O2-二氧化硫脲体系引发桉木浆与甲基丙烯酸缩水甘油酯(GMA)的接枝共聚.初步讨论了该引发体系的引发机理,用接枝率、接枝效率和单体转化率考察了温度、反应时间、过氧化氢用量、二氧化硫脲用量、单体浓度和液比对接枝的影响.并用红外光谱对接枝纤维产物进行了鉴定.结果表明,组分二氧化硫脲的加入能有效地使接枝共聚得以顺利进行.适当提高温度,增加过氧化氢用量,减小液比,控制合适的二氧化硫脲用量都能提高接枝率和单体转化率,并在较短的时间就能成功接枝.接枝效率几乎不受任何因素的影响,一般维持在97%~99%,接枝过程产生的均聚物极少. 相似文献
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以木质素磺酸钠(LS-Na)、丙烯酸(AA)、丙烯酰胺(AM)为原料,高岭土(Kaolin)为无机添加剂,过硫酸钾(KPS)为引发剂,N,N’-亚甲基双丙烯酰胺(NMBA)为交联剂,通过溶液聚合制备高岭土/木质素磺酸钠-g-AA-AM复合高吸水树脂(LPAAM)。选用正交试验设计方法,以蒸馏水和0.9%NaCl溶液中的平衡吸液倍率为评价参数得到了较优配方:m(AM):m(AA)=1:1,m(KPS)=1.0%,m(NMBA)=0.1%,pH=3。将上述配方制备的LPAAM以不同浓度NaOH于90℃皂化2h,得到皂化后的LPAAM,该树脂在蒸馏水和0.9%NaCl溶液中的平衡吸液倍率分别为1003及89g·g-1。 相似文献
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木材酯化及接枝共聚处理对木材表面自由能影响的研究 总被引:7,自引:0,他引:7
采用接触角测定法,对经用乙酰化法酯化和苯乙烯单体接枝共聚处理改性前后的杉木和杨树表面接触角的变化和表面自由能变化值进行了研究,确定了木材的酯化和接枝共聚改性对木材表面自由能变化的影响因素,研究结果表明,在酯化和接枝改性处理后,液体在杉木和杨木表面上的接触角比在未经处理的木材表面的接触角有所增大,酯化处理产生的接触角增大作用要比接枝共聚所产生的作用大,杉木和“三北一号”杨的表面自由能分别为42.8mN/m和52.3mN/m与大部分木材垢表面自由能相近,木材的酯化的接枝共聚改性可以隆低木材的表面自由能,但酯化对表面自由能的降低各充受树种的影响,而接枝共聚改性对表面自由能的降低基本上不受处理树种的影响。 相似文献
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-TD引发体系下TMP与MMA接枝工艺的研究 总被引:1,自引:1,他引:0
研究了Fe^2+-H2O2-二氧化硫脲(TD)引发体系下热磨机械浆(TMP)浆料与甲基丙烯酸甲酯(MMA)的接枝共聚工艺。分析了在该引发体系下各反应条件对接枝率、接枝效率和单体转化率的影响。结果表明,TD的加入能有效地使接枝共聚得以顺利进行;适当提高温度,增加单体浓度,控制合适的TD用量都能提高接枝率和接枝效率,并能在较短的时间成功接枝;接枝率一般维持在80%以上,适宜条件下能达到91%。 相似文献
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To improve the wet-end properties of linear-type copolymerized polyacrylamide (co-PAM), three types of cationic co-PAM were prepared by graft copolymerization, and their effects on the drainage, paper strength, and filler retention were investigated. Of the three synthesized terpolymers, dextrin-acrylamide-2-(dimethylamino)-ethylmethacrylate graft terpolymers (Dex-graft-(AM-DMAEMA)) moderately improved the wet-end properties compared with the other two graft terpolymers prepared. Notably, addition of 0.1% (on dry pulp) Dex-graft-(AM-DMAEMA) showed high filler retention of 78%. All of the prepared graft terpolymers showed equal or improved wet-end properties compared with acrylamide-2-(dimethylamino)ethylmethacrylate copolymer (AM-DMAEMA), which is a standard cationic co-PAM of similar moleculer weight.Part of this paper was presented at the meeting of the Chubu Branch, Japan Wood Research Society, Kakamigahara, September 13–14, 2000 相似文献