硅灰石表面改性及其在聚丙烯中的应用

采用硅烷对硅灰石进行了表面改性实验,将活化后的粉体加入聚丙烯材料中,研究了硅烷改性对聚丙烯/硅灰石复合材料性能的影响。通过对改性前后粉体吸油值及红外光谱分析以及对填充聚丙烯材料新鲜断面的扫描电镜分析,研究硅烷改性硅灰石的效果和改性机理。结果表明:硅烷偶联剂适宜用量为硅灰石质量的0.8%~1.2%,改性温度为80℃,时间为15~20 min。表面改性可以显著提高聚丙烯/硅灰石复合材料的拉伸强度、弯曲强度、弯曲模量、热变形温度等性能指标。     

硅灰石表面无机改性及其在聚丙烯中的应用

采用非均匀成核法,通过在硅灰石表面包覆硅酸铝对硅灰石进行了无机改性。扫描电镜（SEM）和X射线衍射（XRD）等测试表明,无机改性硅灰石颗粒表面粗糙,包覆着许多纳米硅酸铝粒子;通过BET比表面积分析仪测定,比表面积提高200%以上;红外光谱（FT-IR）测试表明,无机改性后硅灰石表面羟基增多;白度测试表明,无机改性硅灰石...     

重质碳酸钙/硅灰石复合填料表面改性研究

研究了表面改性剂配方、用量、改性时间等对重质碳酸钙／ 硅灰石复合填料表面改性效果的影响，以及表面改性与复合填料表面的作用机理     

硅灰石针状粉的表面改性及在橡胶中的应用

通过对硅灰石针状粉的表面改性效果及在橡胶中的应用试验研究，认为硅灰石的改性时间、改性温度、改性剂用量、转子转速等工艺条件对硅灰石的改性效果有影响；改性后的硅灰石在橡胶中使用，可赋予橡胶制品良好的耐磨、耐老化和耐疲劳性能，但对橡胶的定伸应力损害目前还是难以克服的；不同种类的偶联剂配合使用、不同形状的矿物填料配合使用对胶料的物理性能有不同的影响。     

硅烷偶联剂改性纳米SiO_2的分散性能

用硅烷偶联剂KH-570对纳米SiO2进行表面改性,用红外光谱仪(IR)、热重(TA)、Zeta电位、SEM、性能测试等对改性纳米SiO2进行了研究,结果表明,偶联剂KH-570与SiO2化学结合形成了Si—O—Si键,其附着量约5.8%,结合溶剂水约10.35%;改性纳米SiO2在乙醇介质中的Zeta电位由-14.9 mV减小到-41.1mV,体系稳定性可达60 h以上;改性SiO2用作光固化牙科复合树脂的填料,分散性显著提高,其维氏硬度、压缩强度、弹性弯曲强度等性能提高10%以上。     

碳化硅颗粒增强铝基复合材料颗粒表面改性技术研究现状

SiC颗粒增强铝基复合材料因具有高的比强度、比刚度、耐磨性及较好的高温稳定性而被广泛应用于航空航天、电子、医疗等领域,但由于SiC颗粒高熔点、高硬度的特点以及SiC颗粒与铝基体间存在界面反应,碳化硅铝基复合材料存在加工性差、界面结合力不足等问题,已无法满足航天等领域对材料性能更高的要求,因此开展如何改善基体与颗粒之间界面情况的研究对进一步提升复合材料综合性能具有重要的科学意义。结合国内外现有研究成果,总结了SiC颗粒与铝基体界面强化机制、界面反应特点、表面改性技术原理及数值建模的发展现状,结果表明,现有经单一表面改性方法处理后的增强颗粒对铝基复合材料性能的提升程度有限,因此如何采用新的手段使复合材料性能进一步提升将成为后续研究热点,且基于有限元数值模拟方法进行复合材料设计也是必然趋势。最后针对单一强化性能提升有限的问题,提出了基于表面改性的柔性颗粒多模式强化方法,同时针对现有的技术难点展望了后续的研究方向,以期为颗粒增强复合材料的制备提供理论参考。     

硅灰石深加工及应用进展

硅灰石是天然产出的偏硅酸盐纤维矿物 ,具有许多优异的工业应用特性。磨细硅灰石是优质的陶瓷原料、冶金助剂 ;高长径比硅灰石是石棉和玻纤的理想代用品 ,可用作橡胶、塑料和油漆涂料的填料 ,起补强和增量的双重作用。本文介绍了硅灰石的工业应用及其深加工进展     

木粉表面自由能和表面极性对木塑复合材料界面的影响

通过毛细管上升法测定了水曲柳木粉(MWF)、落叶松木粉(MWF)的表面接触角,依据Washburn方程和Owens法,求解水曲柳木粉和落叶松木粉的表面自由能及其极性和非极性分量。结果表明,水曲柳木粉的表面自由能为36.06mN/m,体现分子色散力的非极性分量为32.54 mN/m;而落叶松木粉的表面自由能为20.17 mN/m,其非极性分量为10.41 mN/m。因此,与同种塑料复合,水曲柳木粉有比落叶松木粉更好的界面粘接性。扫描电子显微镜进一步证实了水曲柳木粉在基体中的分散性好于落叶松木粉。     

水镁石粉体表面改性及表面能测算

水镁石粉体是聚合物的常用填料,但水镁石极性较大,与基材的相容性也较差,因此必须通过表面改性,降低水镁石粉体表面能,增强亲油疏水性,从而增加与聚合物之间的相容性,而阴离子表面活性剂是合适的改性剂之一。水镁石粉体改性后的表面性能,可以用固体表面能数值的变化来表征,本文选择丙三醇、水、1-溴代萘为探针液体,用直接测定法与Washburn方程间接计算法获得了改性前后水镁石的接触角,通过Lifshitz-van der Waals acid base三参数法计算其表面能。研究结果表明,不同的阴离子基团中,羧酸类、磷酸较之磺酸类硫酸类改性效果有明显优势,表面能的碱分量γ-S和酸分量γ＋S降为0;随着改性剂中非极性链烃的碳原子个数增加,表面能非极性分量γLSW下降很多,最终导致总表面能下降,接触角增加,疏水性增强。     

二氧化硅/硅灰石复合颗粒的制备研究

以水玻璃为主要反应原料 ,利用无机化学沉积改性制备二氧化硅 /硅灰石矿物复合颗粒 ,并利用扫描电镜(SEM)与X荧光光谱分析及力学实验等测试方法表征了该实验的可行性并得出相应结论     

纳米ATO在有机单体介质中的表面改性及分散研究

选用了多种改性剂,用超声波为分散手段,将纳米ATO粉体在有机单体介质中进行表面改性和分散,研究了改性剂种类、改性剂用量、改性时间、超声波输出功率和超声波处理时间等对纳米ATO-单体分散液稳定性的影响,探讨了纳米ATO表面改性机理.结果表明,硅烷偶联剂KH-570是纳米ATO的最佳改性剂,当其用量为纳米ATO的15%(质量分数),改性时间为24h,超声波输出功率为90%,超声波处理时间为12min时,纳米ATO-单体分散液具有最佳的分散稳定性.KH-570主要通过在纳米ATO表面水解产生硅羟基的自缩合,形成包覆改性.     

纳米TiO2表面无机/有机复合改性研究

用液相沉积法对纳米TiO2进行了表面无机/有机复合改性.用XRD、FT-IR进行了包覆膜结构表征,用TEM观察改性后颗粒的形态.测量了有机包覆量对改性样品亲油性的影响.结果表明,液相沉积并经105℃烘干得到的Al2O3膜为非晶态结构,煅烧后才能晶化;有机膜可以在无机膜上生成,其最大包覆量约为7%,且与包覆温度无关;复合包覆后纳米颗粒外形不变,分散性提高;有机包覆量对纳米TiO2的亲油性有非线性影响,包覆量为1.2%时其亲油性最好.     

Surface modification and characterization for dispersion stability of inorganic nanometer-scaled particles in liquid media

Abstract

Inorganic nanoparticles are indispensable for science and technology as materials, pigments and cosmetics products. Improving the dispersion stability of nanoparticles in various liquids is essential for those applications. In this review, we discuss why it is difficult to control the stability of nanoparticles in liquids. We also overview the role of surface interaction between nanoparticles in their dispersion and characterization, e.g. by colloid probe atomic force microscopy (CP-AFM). Two types of surface modification concepts, post-synthesis and in situ modification, were investigated in many previous studies. Here, we focus on post-synthesis modification using adsorption of various kinds of polymer dispersants and surfactants on the particle surface, as well as surface chemical reactions of silane coupling agents. We discuss CP-AFM as a technique to analyze the surface interaction between nanoparticles and the effect of surface modification on the nanoparticle dispersion in liquids.     

多壁碳纳米管的表面修饰及其在溶剂中的分散性

利用高温催化裂解生长多壁碳纳米管,用硝酸氧化使其表面羧酸化,并经酰氯化后与十二烷基胺反应形成表面酰胺化,通过红外、核磁、微量热天平等方法进行表征.结果表明:硝酸氧化后的碳纳米管在水等强极性溶剂中有良好的分散性;酰胺化后,十二烷基脂肪链使碳纳米管表面极性大为降低,因此在氟仿等弱极性溶剂中有良好的分散性.     

Surface modification of implant materials and its effect on attachment and proliferation of bone cells

Osteoblast-like cell response in variation with the air plasma sprayed (APS) TiO2 coating process parameters correlated with coating properties were investigated to evaluate the durability and biocompatibility of the surface-modified implant. The Taguchi technique was used to determine the coating properties affected by plasma spraying parameters on Ti-6AI-4V alloy substrate. The coating properties were characterized by porosity and surface roughness using an image analyzer and surf analyzer, respectively. The MG-63 osteoblast like cell morphology and proliferation data on TiO2 coated substrate were measured by SEM observation and direct cell counting. It was demonstrated that surface roughness increased as spray distance decreased but gas flow rates and spray distance were major factors in the case of porosity. The osteoblast adhesion morphology and proliferation data indicated that osteoblast-like cell morphology was not influenced by process parameters, but cell proliferation was affected to some extent by surface roughness and porosity among TiO2 coated specimens. Specifically, the difference between those of substrate and coating layer was relatively more visible.     

超滤膜的改性研究及应用

随着超滤膜技术的发展，人们对超滤膜提出了各种各样的特性要求，其中解决膜表面的污染问题变得越来越紧迫．超滤膜改性，尤其是在膜表面引入亲水性基团是解决问题的关键．本文从这点出发，结合自身的工作，总结了近年高分子超滤膜改性方面的研究进展，包括表面活性剂在膜表面的吸附改性、等离子体改性、辐照改性、高分子合金和表面化学反应等几种改性方法．     

Surface modification for polystyrene colloidal particles with controlled charge densities

A significant amount of polystyrene sulfonated acid (PSSA) and poly(styrene-ran-acrylic acid) (PSAA) random copolymer can be adsorbed by dispersion of PS particles via a swelling-quenching process. A THF-water mixed solvent was used in the swelling process and a large amount of pure water was used, to give a low concentration of THF% in quenching process. Our results showed that functional PSSA groups were randomly and tightly adsorbed to the PS particles. When the mol.% of charged segments was increased, the progressive adsorption of PSSA chains to the PS particles leads to an increase in the electrophoretic mobility and zeta-potential of aqueous dispersions. Thus, we were able to obtain well-distributed surface charge density on the PS particles.     

Surface modification of silica particles with polyimide by ultrasonic wave irradiation

Spherical silica particles were dispersed in a polyamic acid varnish (PAAV) solution, and ultrasonic wave irradiation resulted in high-speed condensation of conversion to polyimide and in coating of the silica particles. The imidization reaction was verified by Fourier transform IR analysis, thermogravimetry, gel-permeation chromatography and moisture analysis. In addition, the particle coating was observed by transmission electron microscopy. Adsorption of polyimide acid onto the surface of the silica particles while achieving an imidization reaction by ultrasonic wave irradiation has been clearly shown to enhance the rate of the imidization reaction.