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李从举  黄丽  肖斌  冯苹 《化学学报》2010,68(6):571-575
首先合成了纳米磷酸钙(NCP),用扫描电镜(SEM)和X射线衍射(XRD)进行了表征.再利用静电纺丝法制备了PLA/NCP复合纳米纤维,对纤维进行了TEM,SEM,XRD以及单轴拉力测试的表征.TEM和XRD测试表明,NCP已成功掺杂到聚乳酸纤维中,获得的纤维为复合纤维.SEM测试表明,NCP在溶液中浓度较小时,复合纳米纤维的形貌变化不大;NCP浓度超过PLA质量的7%后,纤维表面出现粒状物;随着浓度继续增大,粒状物逐渐增多,最后很难成纤.拉伸实验结果表明,复合纤维拉伸强度先随着NCP浓度的增加而增大,但NCP浓度超过7%后拉伸强度随着浓度的增加反而减小.  相似文献   
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纳米钛酸钙粉体的制备及其对水中铅和镉的吸附行为   总被引:2,自引:0,他引:2  
张东  侯平 《化学学报》2009,67(12):1336-1342
采用柠檬酸络合溶胶-凝胶法制备了纳米钛酸钙粉体. 以X射线衍射(XRD)、透射电子显微镜(TEM)和傅立叶变换红外光谱(FTIR)对其进行了表征. 考察了该纳米粉体对水中重金属铅和镉的吸附性能, 并以镉离子为例, 系统地研究了吸附热力学和动力学. 结果表明, 该法合成的钛酸钙为钙钛矿结构的纳米粉体, 粒径大小受灼烧温度的影响, 灼烧温度越高, 粉体平均粒径越大, 600 ℃灼烧2 h条件下, 粉体的平均粒径最小, 约为20 nm. 当介质的pH值为4~8时, 钛酸钙对水中的铅和镉具有很强的吸附能力. 其对镉离子的吸附行为符合Langmuir 吸附等温模型和HO准二级动力学方程式, 吸附过程焓变(ΔH)为39.312 kJ•mol-1, 各温度下的自由能变(ΔG)均小于零, 熵变(ΔS)均为正值, 吸附过程的活化能(Ea)为20.359 kJ•mol-1. 该吸附过程是自发的吸热物理过程. 被吸附的铅和镉均可用1 mol•L-1的硝酸完全洗脱回收. 对铅和镉的富集因子均超过200. 将其应用于水中痕量铅和镉的吸附富集和测定, 回收率分别为96.3%~107.2%和93.5%~104.0%, 与石墨炉原子吸收光谱法测定结果一致.  相似文献   
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A nano-calcium carbonate (CaCO3)/silane coupling agent (NCC/SCA) master batch was prepared by the reaction of SCA (γ-aminopropyl triethoxy silane, trade name KH550) with the hydroxyl groups of nano-CaCO3. Both Fourier transform infrared spectroscopy and thermal gravimetric analysis indicated that the nanoparticles were grafted by SCA. An epoxy resin was modified by adding the NCC/SCA master batch. A simple dipping test suggested that a better dispersion of the treated NCC in epoxy could be obtained than that of the untreated NCC. Then samples of epoxy nano-composites were prepared by a hot press process. The compressive property of epoxy nano-composites was investigated; the results of these mechanical property tests revealed that the compressive strength, elastic modulus, and the total fracture work of the epoxy matrix filled with the treated NCC were significantly improved relative to that filled with the untreated NCC.  相似文献   
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Composites of polyamide 66 (PA66)/maleic anhydride grafted poly(ethylene-co-octene) (POE-g-MAH)/nano-calcium carbonate (nano-CaCO3) and PA66/POE-g-MAH/talc were prepared by a one-step blending method. Morphology, crystallization, and mechanical properties of the composite materials were characterized with respect to different amounts of both inorganic fillers, nano-CaCO3 and talc. Results showed that the tensile yield strength and tensile modulus of the composites were increased remarkably with introduction of nano-CaCO3 or talc, but the notched impact strength was significantly lowered for both kinds of composites. Mechanical properties exhibited little difference between the PA66/POE-g-MAH/nano-CaCO3 and PA66/POE-g-MAH/talc composites both for the different shapes and sizes of nano-CaCO3 and the flake-like talc. Results of scanning electron microscopy exhibited agglomeration of the fillers. Differential scanning colorimetry analysis suggested that introduction of the inorganic fillers cause the crystallinity of PA66 to decrease by heterogeneous nucleation. The study provides a basic investigation on polymer/elastomer/rigid filler composites.  相似文献   
5.
The influence of malonic acid (MA) treatment of nano-calcium carbonate (CaCO3) on the crystallization, morphology, and mechanical properties of isotactic polypropylene (iPP)/nano-CaCO3 composites have been studied. The results of differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and polarized light microscopy (PLM) show that untreated nano-CaCO3 facilitates the formation of α phase, while MA treated nano-CaCO3 increases the relative content of β phase of iPP dramatically. The results of scanning electron microscopy (SEM) show that MA treated nano-CaCO3 has better dispersion in the matrix than the untreated one. The toughness of PP/MA treated nano-CaCO3 composite is improved drastically. When 2.5 wt% MA treated nano-CaCO3 is added, the Izod notched impact strength reaches its maximum, which is 2.89 times greater than that of the pure iPP.  相似文献   
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