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接枝共聚法合成高吸水性树脂 总被引:3,自引:0,他引:3
以过硫酸钾为引发剂,过硫酸钾与玉米淀粉的质量比为0.014;糊化的玉米淀粉与丙烯酸按质量比1∶6的比例发生接枝聚合反应.反应温度50 ℃,反应时间2.5 h~3.0 h,丙烯酸的中和度为92%,制得高吸水性树脂,并讨论了其吸水性能.在室温、中性酸度环境下,合成的高吸水性树脂吸水倍率最高,可达到560 g/g。 相似文献
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以N,N’-亚甲基双丙烯酰胺为交联剂,过硫酸钾为引发剂,马铃薯淀粉与丙烯酸及其钠盐接枝共聚合成了交联型淀粉接枝丙烯酸高吸水树脂。研究了交联剂、引发剂和中和对高吸水树脂吸水率的影响。合成的最佳高吸水树脂的吸液能力(g/g)为:去离子水1240,自来水390,人工血95,生理盐水80,人工尿70。同时对高吸水树脂的吸水速率、不同浓度的NaCl溶液下的吸水量和不同的pH下的吸水量进行了测试。高吸水树脂45min内吸水量就达1050 g/g,在pH为3~9之间有较高的吸水量。 相似文献
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通过改变吸水树脂质量、吸液时间、外部溶液离子强度等条件,用过滤法测定淀粉接枝聚合物的吸水率和吸水速率.经分析,测定淀粉系高吸水性树脂吸水率的合理条件为:干树脂粒径在60~80目之间,质量1.500g,吸水时间为30min;外部离子浓度越高,吸液率越低. 相似文献
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以玉米淀粉为原料合成了可生物降解的高吸水树脂,并在淀粉中引入磷酸根离子,然后对制备的树脂进行保水保肥等性能的研究。结果表明:磷酸酯淀粉类高吸水树脂具有较好的吸水性能,吸水倍率达339.65g/g,对0.9%NaCl溶液的吸液率有71.90g/g。树脂对氮肥的吸附量随氮肥浓度的增加而增加,在硫酸铵浓度为24g/L时达到最大值405.82mg/g;树脂加入土壤后,最大吸氮量达344.99mg/g。磷酸酯淀粉类高吸水树脂加入土壤后能改善土壤结构,提高土壤的保水保肥性能。最佳树脂用量为1.5%,当超过这个用量,树脂吸水膨胀后对土壤结构不利。用量为1.5%的树脂与土壤混合5d后,释放量不超过吸附的26%。 相似文献
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耐盐性魔芋葡甘聚糖吸水树脂的制备 总被引:4,自引:0,他引:4
以魔芋葡甘聚糖(KGM)为原料接枝丙烯酰胺、丙烯酸制备耐盐性吸水树脂,研究了接枝共聚反应单体及KGM质量配比、中和度、交联剂浓度、引发剂浓度、乙二胺四乙酸(EDTA)质量分数对吸水树脂吸液倍率的影响,通过Box-Behnken实验设计对制备条件进行优化。结果表明,丙烯酰胺与丙烯酸质量比为0.192,交联剂浓度为0.067g/mol,引发剂浓度为0.439g/mol,中和度为90%,乙二胺四乙酸(EDTA)质量分数为12.2%时,该耐盐性树脂吸生理盐水倍率达125g/g,吸纯水倍率达700g/g。 相似文献
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交联羧甲基玉米淀粉/PVA复合膜制备工艺的研究 总被引:5,自引:2,他引:3
以玉米淀粉为原料,采用先醚化后交联改性工艺合成了交联羧甲基玉米淀粉(CCMS).通过改性淀粉与聚乙烯醇(PVA)溶液共混反应,并辅以增塑剂、增强荆、交联剂及疏水化改性剂等加工助荆制备了性能优异的CCMS/PvA复合膜.研究了复合膜制备过程中的影响因素及其对薄膜耐水性能、透光性能和力学性能的影响.结果表明,当交联羧甲基玉米淀粉与PVA的质量比为7:3,甘油用量为10%(质量分数),复合交联剂用量3.3%(质量分数),疏水化改性荆聚酰胺多胺环氧氯丙烷树脂(PPE)用量为1.5%(质量分数),溶液pH为10,反应温度88℃,反应时间35min时,淀粉膜的拉伸强度为40.5MPa,断裂伸长率为311%,透光率为82%,吸水率最小为3.6%(质量分数). 相似文献
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A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling. 相似文献
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An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a
rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate
agreement is demonstrated between the derived relations and experimental data. 相似文献
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Liebert A Wabnitz H Grosenick D Möller M Macdonald R Rinneberg H 《Applied optics》2003,42(28):5785-5792
A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue. 相似文献
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水三相点是开尔文热力学温度的唯一基准点,也是ITS-90国际温标重要的定义固定点。因此,水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来,中国计量科学研究院研制出一系列高质量的水三相点容器,加强了水三相点的研究,为不确定度的分析提供了更为可靠的实验依据。同时,不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此,根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明,其扩展不确定度为0.16mK(k=2.69,P=0.99)。 相似文献
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Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995. 相似文献