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反相悬浮法制备聚(丙烯酸-丙烯酰胺)/粉煤灰高吸水树脂 总被引:1,自引:0,他引:1
《化工新型材料》2017,(2)
以丙烯酸和丙烯酰胺为单体,过硫酸钾为引发剂,N,N′-亚甲基双丙烯酰胺为交联剂,Span80为分散剂,环己烷作为油相,采用反相悬浮聚合法合成聚(丙烯酸-丙烯酰胺)高吸水性树脂。探讨了油水比、分散剂用量和交联剂用量对树脂形态和吸液性能的影响。制备的高吸水树脂最佳吸蒸馏水倍率和吸盐水倍率分别为956g/g和137g/g。引入质量分数为9%的粉煤灰后,树脂仍能保持较高的吸水倍率和吸盐水倍率,分别为616.4g/g和66.3g/g。 相似文献
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以过硫酸钾(KPS)为引发剂,N,N’-亚甲基双丙烯酰胺(NMBA)为交联剂,丙烯酸(AA)、丙烯酰胺(AM)和绢云母为原料,采用快速水溶液聚合法,在没有氮气保护的条件下制备有机-无机复合高吸水树脂。采用傅里叶红外光谱(FT-IR)、扫描电镜(SEM)对复合高吸水树脂结构进行了表征。考察了单体配比、绢云母用量、丙烯酸中和度、交联剂用量、引发剂用量对高吸水树脂吸液性能的影响。得到了最佳聚合反应条件:丙烯酰胺与丙烯酸的质量比为1∶5,交联剂用量为0.014%,引发剂用量为0.2%,绢云母用量为5%,丙烯酸中和度为80%,反应温度为65℃。在此条件下制备的复合高吸水树脂的蒸馏水吸收倍率为790g/g,0.9%的NaCl水溶液的吸收倍率为69.8g/g。最后,对聚(丙烯酸-丙烯酰胺)/绢云母复合高吸水树脂的机理进行了探讨。 相似文献
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采用水溶液聚合法制备高岭土复合聚(丙烯酸-co-丙烯酰胺)高吸水树脂,用红外光谱对树脂的结构进行表征。在将聚合反应与树脂的干燥同时进行的基础上探讨了交联剂用量、引发剂用量、单体配比、丙烯酸中和度、高岭土添加量等条件对树脂吸液性能的影响。结果表明:当丙烯酸中和度75%、单体配比3.5:1、高岭土添加量15%、交联剂用量0.02%、引发剂用量0.8%时,树脂的吸液性能整体最好,吸水倍率达698g·g-1、吸盐水倍率110g·g-1。红外光谱结果表明,丙烯酸、丙烯酰胺单体与高岭土的-OH发生了接枝共聚反应。 相似文献
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以过硫酸钾为引发剂,N,N'-亚甲基双丙烯酰胺为交联剂,丙烯酸、2-丙烯酰胺-2-甲基丙磺酸(AMPS)为单体,聚乙烯醇为有机合成聚合物,硅藻土为无机黏土,采用水溶液聚合法合成有机/无机复合高吸水树脂。采用傅里叶变换红外光谱仪、扫描电子显微镜和热重分析仪对有机/无机复合高吸水树脂进行了表征,考察了引发剂用量、交联剂用量、AMPS用量及硅藻土用量对复合吸水树脂吸液性能的影响。在最佳反应条件下,有机/无机复合高吸水树脂吸蒸馏水倍率、吸0.9%生理盐水倍率分别为1574g/g和101g/g;纯有机高吸水树脂暴露在空气中的吸湿性是复合高吸水树脂的20~30倍,说明有机/无机复合高吸水树脂具有优异的防潮性能,在不同阳离子盐溶液中(Na~+、Ca~(2+)和Fe~(3+))其吸液性能明显优于纯有机高吸水树脂。 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,丙烯酸(AA)和丙烯酰胺(AM)为单体,采用水溶液聚合法合成出钠基膨润土复合聚丙烯酸钠-丙烯酰胺复合吸水树脂.研究了钠基膨润土的添加量、交联剂用量、引发剂用量、中和度及AM的用量对吸水倍率的影响.结果表明,钠基膨润土用量为40%,交联剂用量为0.025%,引发剂用量为0.3%,AM用量为12%及AA的中和度为80%时,吸蒸馏水倍率与吸收0.7%NaCl溶液倍率分别为422.28 g/g和65.80 g/g. 相似文献
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《Advanced Powder Technology》2020,31(4):1659-1664
Concentrated slurry is known to exhibit shear thickening behavior, in which viscosity increases as the shear rate ascends. However, to identify the differences between this shear thickening behavior and rapid increases in viscosity (such as the dilatancy behavior of starch, sand, and other concentrated slurries) and the smooth increases in viscosity exhibited by concentrated slurries, this research investigated the rheological behavior of a polyethylene glycol suspension containing monodispersed silica particles with a size of 2.5 μm. The results found that the increases in viscosity as the shear rate ascends or the increases in elasticity as the strain ascends change consecutively from smooth and reversible behavior (i.e., continuous shear thickening (CST)) to rapid and irreversible behavior (i.e., discontinuous shear thickening (DST)) simply by increasing the concentration of the slurry, even in the case of concentrated slurries comprising of the same particles. DST is a manifestation of dilatancy in which a jamming transition occurs due to collisions between particles. Because CST transitions successively to DST, and the on-set shear stress of shear thickening of CST is almost the same with that of DST, shear thickening in the CST region may, therefore, also be regarded as the result of friction due to collisions between particles. This supports the research by Seto, Mari, Poon et al., which stated that shear thickening occurs due to friction from particle collisions. 相似文献
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剪切增稠液体的制备及其性能表征 总被引:2,自引:0,他引:2
研制了一种新型功能材料——剪切增稠液体(Shear thickening fluid,即STF)。采用溶胶凝胶方法制备纳米二氧化硅作为分散相,极性溶剂作为分散介质。用流变仪测量了二氧化硅质量分数分别为30%、40%、50%、60%和70%的体系稳态和动态粘度曲线,结果表明,在低剪切速率下,出现剪切变稀现象,在高剪切速率下,出现剪切增稠现象。从实验角度证明了剪切增稠的可逆性。并对不同固相含量的剪切增稠液体的性能进行了分析比较。 相似文献
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温敏凝胶流变性能动力学研究 总被引:1,自引:0,他引:1
应用动态流变实验测定了温敏共聚物的流体特性,分析其在溶胶-凝胶转变过程共聚物溶液随温度变化形成凝胶机理。以室内合成的四元共聚物溶液为基础,采用动态流变实验测定了该共聚物溶液在不同温度、浓度下的剪切模量和损耗模量的变化,确定了凝胶特性,并与试管倒置法比较了凝胶温度。实验结果表明,临界温度为143℃,在一定浓度下(高于接触浓度C*),低于此温度共聚物溶液具有一般粘性流体特性;高于此温度可形成凝胶网络结构;溶液在测试温度(65~240℃)内,其损耗角从56.27°逐渐变为31.04°,溶液体系从粘性流体逐渐到粘弹性流体过渡;说明该溶液在一定浓度下具有温敏特性。 相似文献
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Nithin Tom Mathew 《Materials and Manufacturing Processes》2017,32(15):1692-1699
One of the major difference in drilling process when related to other conventional metal removal processes like turning and milling is that the drill tool has to work beneath harsh environment as the metal cutting region is situated deep inside the work material. Also, the chip flow is restricted only through the flutes, and hence there occurs transformation of chip shape, chip thickening, and changes in force and torque. In the present investigation, high throughput drilling has been performed under a dry and wet environment in an intermetallic titanium aluminide which is an exceptional class of material with superior properties. It is found that the chip shape transformed from spiral to folded ribbon as the depth of hole increased. Also, a substantial increase in chip thickness, thrust, and torque was observed, and toward the end of drilling, chip clogging occurred. An analytical model was established by applying the mechanics of oblique cutting to find the torque and thrust by measuring the thickness of chip, and this model was validated experimentally. 相似文献
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Kanai H. Hasegawa H. Chubachi N. Koiwa Y. Tanaka M. 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1997,44(4):752-768
For the noninvasive diagnosis of heart disease based on the acoustic characteristics of the heart muscle, we have developed a new method for accurately tracking the movement of the heart wall. By this method, a velocity signal of the heart wall with a small amplitude of less than 10 μm on the motion resulting from a heartbeat with large amplitude of 10 mm can be successfully detected with sufficient reproducibility in the frequency range up to several hundred Hertz continuously for periods of about 10 heartbeats. In this paper, the method is applied to multiple points preset in the left ventricular (LV) wall along the ultrasonic beam so that the spatial (depth) distributions of the velocity at these points are simultaneously obtained. The motion of the heart wall is divided into the following two components: parallel global motion of the heart wall and the change in myocardial layer thickening at each depth across the LV wall during myocardial contraction/relaxation. The latter component is superimposed on the M (motion) mode image using a color code to map contraction as red and expansion as blue. By preliminary human studies, the principle of the method proposed in this paper is verified and the frequency band of the components generated by thickening and/or thinning in the myocardium is identified. This new approach offers potential for research on noninvasive acoustical diagnosis of myocardial local motility, that is, the myocardial layer function at each depth in the ventricular wall 相似文献
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R. Cristian Neagu Pierre-Etienne Bourban Jan-Anders E. Månson 《Composites Science and Technology》2009,69(3-4):515-522
Damping is an important parameter for vibration control, noise reduction, fatigue endurance or impact resistance of composite materials. In this study, a micromechanical model was used to predict the damping of a composite material containing shear thickening fluids (STFs) at the fibre–matrix interfaces. Predictions of the model and dynamical mechanical analysis results are in concert. The damping of the composites was improved significantly. The dynamic properties exhibited a strong dependence on both frequency and applied external load amplitude. Damping peaks appeared which coincided with the thickening of the STF at the fibre–matrix interface. The location of the peaks depends on the onset of thickening and post-thickening rheological behaviour of the STF. This work shows that a micromechanics approach can be useful for an appropriate choice of microstructural design and properties of STFs in order to control the stiffness and damping behaviour of composites. STFs can be integrated at the microscale of polymer composites to create new materials with load-controlled adaptive dynamic stiffness-damping properties. 相似文献