纳米SiO_2增强增韧聚丙烯(PP)的研究

采用微胶囊包覆的方法对二氧化硅无机纳米粒子(nano SiO2)进行了表面处理,然后通过熔融共混法制备聚丙烯(PP)/ SiO2 纳米复合材料。力学性能测试、DSC及材料断面形貌分析等表明:用此改性方法制得的 nano SiO2 微胶囊采用常规的熔融混合法就能在基体树脂PP中达到纳米级的均匀分散,且在复合材料中可起异相成核的作用,从而提高 PP的结晶温度和结晶度,并能使PP/SiO 复合材料的拉伸强度提高43%,缺口冲击强度提高107%。     

纳米SiO2的表面处理及HDPE/SiO2复合材料研究

采用多种方法对纳米SiO2粒子进行表面处理,通过母料法工艺制备了HDPE/纳米SiO2复合材料,研究了纳米SiO2的含量对HDPE复合材料性能的影响.结果表明:经适当处理的纳米SiO2粒子能均匀地分散在HDPE中,能显著改善HDPE复合材料的力学性能;当纳米SiO2的质量分数为6%时,HDPE复合材料的综合力学性能最佳.     

PP／SiO2纳米粒子复合材料中偶联剂用量的确定

目的：探索聚丙烯／二氧化硅（PP／SiO2）纳米粒子复合材料中偶联剂的最佳用量。方法：首先用熔融共混法制备PP／SiO2纳米粒子复合材料,再通过分析复合材料的力学性能和冲击试样断面的SEM照片来探索硅烷KH－560的最佳用量。结果：硅烷KH－560的用量为SiO2纳米粒子的10％时,PP／SiO2纳米粒子复合材料的综合力学性能最佳。结论：传统的计算处理微米级无机填料硅烷用量的经验公式不能适用于无机纳米粒子。     

纳米二氧化硅粒子增韧聚丙烯的研究

研究了纳米二氧化硅(SiO2)粒子对聚丙烯(PP)的冲击强度和拉伸强度的影响，比较了溶液共混法与聚合法的改性效果差异，并从机理上进行了探讨．研究发现：用溶液共混法制备的纳米SiO2／PP复合材料，其冲击强度在纳米SiO2粒子含量为4％左右时达到最大值，约为未经改性的PP材料的8倍；用纳米SiO2粒子改性的PP材料的拉伸强度与未经改性的PP材料基本一致；在相似的工艺条件下，共混法对PP的增韧效果较聚合法显著．     

SiO2纳米粒子增强改性聚乙烯力学性能的研究

以不同比例的SiO2纳米粒子与mLLDPE／LDPE基材进行熔融共混所获得的复合材料为研究对象,力学性能测试和SEM、TEM观察照片研究结果表明：当使用经处理的2％SiO2纳米粒子时,其复合材料力学性能达到最佳值;与纯mLLDPE／LDPE相比,拉伸强度、断裂伸长率分别提升了13．7MPa和174．9％,表明了SiO2无机纳米粒子被分散于基材中,与基材形成牢固的界面结合,与基体树脂之间的链段发生缠结,形成了有利于力学性能提高的界面结构．     

聚丙烯/纳米SiO2 复合材料的制备和表征

使用熔融共混法制备了聚丙烯（PP）／纳米SiO2复合材料。研究发现，硅烷偶联剂对纳米SiO2在PP中的分散起一定的作用，但不是非常有效。添加马来酸酐接枝聚丙烯（PP—g—MAH）相容剂后，可以使纳米SiO2均匀地分散于PP中。当纳米SiO2的质量分数为2％时性能较优，与纯PP相比，V形缺口冲击强度提高了90％，拉伸强度提高了5％，弯曲强度提高了23％。最后，对PP—g—MAH大幅度改善纳米SiO2在PP中分散效果的机理作了初步推断。     

纳米ZnO/PP复合材料性能研究

以钛酸酯偶联剂对不同粒径的纳米ZnO粒子进行表面处理 ;采用熔融共混工艺制备了纳米ZnO/PP复合材料 ;并对复合材料力学性能及其结晶性能进行研究。结果表明 :偶联剂改善了复合材料的力学性能 ;平均粒径为 80nm的纳米ZnO质量分数为 4 %时 ,其复合材料的综合性能相对较好 ,复合材料的冲击强度、拉伸强度和弯曲强度均得到不同程度的提高 ;纳米ZnO具有异相成核作用 ,能够起到细化PP球晶的作用。     

纳米SiO2增强增韧HDPE的研究

采用微胶囊包覆的方法对二氧化硅无机纳米粒子进行表面处理．然后通过熔融共混法制备高密度聚乙烯(HDPE)／SiO2纳米复合材料．力学性能测试技材料断面形貌分析等显示．此改性方法制得的纳米SiO2微胶囊采用常规的熔融混合法就能在基体树脂HDPF中达到纳米级的均匀分散，对基体树脂HDPE具有明显的增强增韧效果。     

PP/SiO2 纳米粒子复合材料中偶联剂用量的确定

目的　探索聚丙烯 /二氧化硅 (PP/Si O2 )纳米粒子复合材料中偶联剂的最佳用量 .方法　首先用熔融共混法制备 PP/Si O2 纳米粒子复合材料 ,再通过分析复合材料的力学性能和冲击试样断面的 SEM照片来探索硅烷 KH-560的最佳用量 .结果　硅烷 KH-560的用量为 Si O2 纳米粒子的 1 0 %时 ,PP/Si O2 纳米粒子复合材料的综合力学性能最佳 .结论　传统的计算处理微米级无机填料硅烷用量的经验公式不能适用于无机纳米粒子     

纳米SiO2对环氧树脂浇铸体性能的影响

以纳米SiO2作为增强材料，制备纳米复合材料，研究了不同的纳米SiO2含量对纳米复合材料冲击强度，拉伸模量，玻璃化温度的影响，采用正电子湮没技术研究纳米粒子对自由体积参数的影响。结果表明，当纳米粒子SiO2含量为3％时，纳米复合材料的拉伸模量为3．57GPa，冲击强度为15.94kJ/m^2，玻璃化温度为126．65℃，分别比纯基体提高了12．6％，56．3％，40．4％。     

Effect of Wet Surface Treated Nano-SiO2 on Mechanical Properties of Polypropylene Composite

Nano-SiO2/polypropylene composite was prepared by melt-blending process. The nano-SiO2 particles were organized by wet process surface treatment with silane coupling agent KH-570. The effect of mass fraction of nano-SiO2 particles and dosage of KH-570 on the toughening and strengthening of PP matrix were investigated based on the fractography of impact notch and the analysis of crystal structure by X-ray and dispersive structure of nano-SiO2 by TEM. Results show that the impact and flexural strength and modulus of the composite are improved obviously with low loading of nano-SiO2 (3wt%-5wt%), and the izod impact strength of PP increases twice with 4wt% nano-SiO2. The nano-SiO2 particles treated can disperse into the matrix resin, which has evident heterogeneous nucleation effects on the crystallization of PP. The optimal toughening and strengthening effects of PP matrix can be obtained when the content of nano-SiO2 and KH-570 are 4wt% and 3wt%, respectively.     

熔融共混制备尼龙6/纳米SiO2复合材料与性能研究

通过熔融共混将表面经硅烷偶联剂改性处理的纳米SiO2与尼龙6(PA6)切片共混,以双螺杆挤出机制备了纳米SiO2增强尼龙6复合材料,其中,纳米SiO2的质量分数为2.5%;借助差示扫描量热仪(DSC)、热重分析仪(TG)、数控毛细管流变仪等仪器研究了其热学性能与流变性能. 结果表明:经硅烷偶联剂表面改性处理的纳米SiO2分散性好,制备的尼龙6/纳米SiO2复合材料热稳定性有所改善、结晶度下降、熔体黏度的切敏性增加.     

A Comparative Study on the Pozzolanic Activity between Nano-SiO2 and Silica Fume

The pozzolanic activity of nano-SiO2 and silica fume was comparatirely stndied by X-ray diffraction （ XRD ） , differential scanning calorimetry （DSC）, scanning electron micrascopy （SEM） and the compressive , bond and bending streugths of hardened paste and concrete were also measured. Results indicate that the compressive strength development of the paste made from Ca（OH）2 and nano-SiO2, the reaction rate of Ca（ OH）2 with nano- SiO2 and the velocity of C-S-H gel formation from Ca （ OH）2 with nano-SiO2 showed marked increases over those of Ca（ OH）2 with silica fume. Furthermore, the bond strength at the interface between aggregate and hardened cement paste, and the bending strength of concrete incorporated with 3% .NS increased more than those with SF, especially at early ages. To sum up, the pozzolanic activity of nano-SiO2 was much greater than that of silica fume. The results suggest that with a small amount of nano-SiO2, the Ca（ OH）2 crystal at the interface between hardened cement paste and aggregate at early ages may be effectively absorbed in high performance concrete.     

纳米SiO2颗粒镍基复合刷镀层组织与磨损特性

应用电刷镀技术制备含有纳米SiO2的镍基复合镀层,测试了该镀层的显微硬度和摩擦磨损性能,分析了纳米陶瓷颗粒沉积量对镀层摩擦磨损性能的影响,研究了复合镀层表面形貌、陶瓷颗粒分布的特点．试验结果表明,纳米陶瓷颗粒复合镀层比快镍镀层具有更高的显微硬度和良好的耐磨性．     

Effect of wet surface treated nano-SiO<Subscript>2</Subscript> on mechanical properties of polypropylene composite

Nano-SiO2/polypropylene composite was prepared by melt-blending process. The nano-SiO2 particles were organized by wet process surface treatment with silane coupling agent KH-570. The effect of mass fraction of nano-SiO2 particles and dosage of KH-570 on the toughening and strengthening of PP matrix were investigated based on the fractography of impact notch and the analysis of crystal structure by X-ray and dispersive structure of nano-SiO2 by TEM. Results show that the impact and flexural strength and modulus of the composite are improved obviously with low loading of nano-SiO2 （3 wt%-5 wt%）, and the izod impact strength of PP increases twice with 4 wt% nano-SiO2. The nano-SiO2 particles treated can disperse into the matrix resin, which has evident heterogeneous nucleation effects on the crystallization of PP. The optimal toughening and strengthening effects of PP matrix can be obtained when the content of nano-SiO2 and KH-570 are 4 wt% and 3 wt%, respectively.     

有机化纳米SiO2填充尼龙66复合物的结构与性能

通过原位表面修饰法制备了有机化纳米SiO2,用熔融共混法制备了尼龙66/SiO2纳米微粒复合材料并研究了复合材料的力学性能.通过示差扫描量热分析(DSC)和动态力学热分析(DMA)研究了复合材料的结晶性能和动态热机械性能.研究表明,纳米SiO2质量分数为4%的复合材料性能提高较为明显,其中简支梁缺口冲击强度提高51.3%,断裂伸长率提高47.3%,弹性模量提高23.8%;纳米SiO2在尼龙66结晶过程中起到异相成核作用,限制了尼龙66的分子链段运动使得复合材料的玻璃化转变温度提高,提高了尼龙66的结晶速率,降低了结晶度;纳米SiO2质量分数为1%复合材料在0℃时的储能模量较纯尼龙66提高21.1%,损耗模量较纯尼龙66提高83.6%,说明纳米SiO2能改善复合材料的低温脆性.     

碳酸钙晶须的制备与填充性能

研究了用CaCl2—MgCl2—Mg(OH)2体系碳化制备CaCO3晶须的过程。结果表明，反应体系中初始的n(CaO)／n(MgCl2)及未转化完全的Ca(OH)2粒子对最终所得产物的形态有决定性作用。在较高的初始n(CaO)／n(MgCl2)下，所得粉体由CaC0。球形粒子、玉米棒状晶须和少量光滑晶须构成。在较低的n(CaO)／n(MgCl2)下，晶须的形成过程不同于高n(CaO)／n(MgCl2)下的情况，可以制备出由大量光滑晶须和少量球形粒子构成的粉体材料。与纳米CaCO3粒子相比,Ca—CO3晶须在一定填充量时对聚丙烯具有较好的增强增韧作用，前者在高含量时具有明显的增韧作用，但会引起拉伸强度下降。     

Preparation of ultra-nano talcum in sand mill and its application in the polypropylene

The grinding of ultra-fine talcum powder and its application in a polypropylene (PP) matrix were investigated. Ultra-fine talcum powder was prepared by adjusting the grinding parameters of the physical milling process. The talcum powder exhibited polymodal distribution. The layered morphology of talcum particles in a horizontal sand mill was rarely damaged or destroyed. PP-talcum nanocomposites were prepared by melt blending using a twin-screw extruder. Nano talcum can be seen as a single particle, although it is not very apparent. The bending strength of talcum-filled PP was gradually increased by approximately 28%. The impact strength linearly decreased as the filler weight ratio increased. The overall maximum improvement in mechanical properties was recorded when the filler ratios increased from 15 wt% to 20 wt%.