纳米SiO2/EP复合材料的制备与性能研究

环氧树脂(EP)固化后交联密度高,呈三维网状结构,存在质脆、耐热性和耐冲击性较差等缺陷,从而限制了其应用范围。通过在环氧树脂中添加纳米Si O2,可以起到增强、增韧和提高热稳定性的作用。本文采用物理共混方法浇铸成型制备纳米Si O2/EP复合材料,并用偶联剂KH-550对纳米Si O2进行表面改性。主要研究纳米Si O2粒子的表面处理、分散方法和粒子添加量对纳米Si O2/EP复合材料力学性能的影响。结果表明:纳米Si O2的加入可以提高Si O2/EP复合材料的力学性能,其中采用偶联剂处理与超声波分散结合时纳米Si O2在环氧树脂基体中的分散效果最佳,当纳米Si O2粒子添加量为3%时,复合材料的的综合性能最佳。     

水性聚氨酯/纳米二氧化硅杂化材料的研究进展

介绍了制备水性聚氨酯(WPU)/纳米Si O2(二氧化硅)杂化材料的几种方法(如纳米Si O2表面改性法、溶胶-凝胶法和原位聚合法等),特别综述了采用化学接枝改性法制备纳米Si O2和溶胶-凝胶法制备共价键连接的杂化材料的研究进展。最后对WPU/纳米Si O2杂化材料的发展方向提出了建议。     

用于离子迁移谱仪进样的纳米二氧化硅增强硅橡胶膜的制备

以六甲基二硅氮烷为改性剂,采用湿法工艺对纳米Si O2进行表面疏水化改性,制备了用于离子迁移谱仪进样的纳米Si O2增强硅橡胶膜,考察了加热温度与反应时间对纳米Si O2的改性效果,研究了改性纳米Si O2与硅橡胶的相容性、纳米Si O2掺杂硅橡胶膜的厚度及拉伸性能。结果表明,在疏水化改性反应中,随着加热温度的升高或反应时间的延长,纳米Si O2表面羟基数下降,比表面积减小,最佳加热温度为120℃,反应时间为4 h;随着反应时间的延长,改性纳米Si O2与硅橡胶的混合液透光度增大,说明纳米Si O2与硅橡胶的相容性提高;以聚苯乙烯为基底材料,采用溶剂挥发工艺制得纳米Si O2掺杂硅橡胶膜的拉伸强度随着纳米Si O2掺杂量的增加而增大,当纳米Si O2与硅橡胶掺杂质量比为30∶100时,可制得厚为2~5μm的最薄硅橡胶膜。     

SBS和纳米SiO2协同增韧增强PP复合材料的研究

将热塑性弹性体苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)及纳米Si O2同时添加到聚丙烯(PP)中,以期在熔融共混过程中发挥SBS与纳米Si O2的协同增强增韧作用,达到有效改善PP综合性能的目的。用硬脂酸(SA)对纳米Si O2粒子表面进行功能化包覆改性,再经熔融共混技术制备了PP/SBS/纳米Si O2复合材料,研究了纳米Si O2表面处理效果及其用量对复合材料力学性能、流变性能及热性能的影响。力学性能研究结果表明,纳米Si O2与SBS对PP具有明显的协同增强增韧作用。当纳米Si O2质量分数为3.84%时,PP/SBS/纳米Si O2复合材料的综合性能最佳,其拉伸强度、断裂强度和拉伸弹性模量分别为37.4,23.8,129.9 MPa,室温(25℃)断裂强度比纯PP提高了100%;其室温和–20℃下缺口冲击强度分别较纯PP提高了51.5%和66.7%。微观形貌分析表明,熔融共混过程中,纳米Si O2均匀分散于PP基体中,复合材料基体在室温冲击下发生明显塑性变形,导致其冲击韧性明显高于低温冲击韧性。与纯PP相比,PP/SBS/纳米Si O2复合材料的流动性增大,耐热变形性能提高。     

无机纳米粒子改性聚氨酯弹性体的研究进展

介绍了用无机纳米粒子改性聚氨酯弹性体的制备方法,综述了纳米Si O2、纳米Zn O、纳米蒙脱土、纳米Ca CO3、纳米Ti O2、碳纳米管以及其他无机纳米粒子改性聚氨酯弹性体的研究进展,指出了无机纳米粒子改性聚氨酯弹性体目前存在的问题。     

聚酰亚胺／纳米Al2O3-SiO2和聚酰亚胺／纳米Si3N4杂化材料的结构与性能研究

将纳米Al2O3-SiO2、Si3N4分别均匀分散于聚酰亚胺（PI）前驱体聚酰胺酸中，经过热亚胺化制备了PI／纳米Al2O3-SiO2和PI／纳米鼠N4杂化材料。通过傅里叶变换红外光谱仪、X射线衍射仪、高温微量热天平、静态热机械分析仪和差示热分析仪对杂化材料的微观结构及热性能进行了研究，结果表明，杂化材料中聚酰亚胺和无机纳米粒子之间存在相互作用，形成了复合相态结构；加入纳米Al2O3，SiO2、Si3N4后杂化材料的热稳定性均高于纯聚酰亚胺，但并不完全随无机纳米粒子含量的增加而提高；与纯PI相比，在90～130℃的温度范围内PI-8％Al2O3-SiO2、PI-8％鼠Si3N4热膨胀系数分别降低了约11％和47％，加入8％纳米Al2O3-SiO2、Si3N4后杂化材料的热导率分别提高了约8％和13％。PI／纳米Al2O3-SiO2、Si3N4杂化材料不仅保留了PI原有的优异性能，而且充分发挥了纳米无机粒子对PI的特殊改性性能。     

纳米Si3N4及其混杂填料改性PTFE的性能研究

采用模压成型的方法制备了纳米氮化硅(Si3N4)与二硫化钼(MoS2)、玻璃纤维(GF)、纳米三氧化二铝(Al2O3)混合填充的聚四氟乙烯(PTFE)复合材料,研究了PTFE复合材料的力学性能和摩擦学性能。采用扫描电子显微镜(SEM)观察分析了拉伸断面形貌及增强机理。结果表明：Si3N4及其混杂填料均使复合材料表面硬度增大;PTFE/Si3N4/Al2O3纳米复合材料具有较好的拉伸性能;混杂填料均可以显著改善PTFE复合材料的耐磨性能,其中5 %的Si3N4与10 %的Al2O3混杂填充复合材料的耐磨性最好,填料对复合材料摩擦因数影响不大。SEM分析表明,纳米Si3N4、Al2O3与PTFE基体界面结合较好。     

纳米二氧化硅改性纸/塑复合用聚氨酯胶粘剂的研究

以γ-氨丙基三乙氧基硅烷(KH-550)、正硅酸乙酯(TEOS)为原料,采用溶胶-凝胶法制备了改性纳米Si O2(二氧化硅);然后将其引入至PU(聚氨酯)胶粘剂中,制备了纸/塑软包装复合用无溶剂PU胶粘剂。研究结果表明:硅烷偶联剂(KH-550)已成功接入至纳米Si O2结构中,改性纳米Si O2的单分散性良好且粒径分布在100~200 nm范围内;当w(改性纳米Si O2)=0.8%(相对于胶粘剂总质量而言)时,胶粘剂的剥离强度(为420 N/m)相对最大。     

纳米粒子混合填充聚四氟乙烯复合材料的性能

采用模压成型法制备纳米Si3N4或SiC与纳米Al2O3混合填充的聚四氟乙烯(PTFE)复合材料,研究不同质量分数的纳米Si3N4或SiC与5%纳米Al2O3混合填充对PTFE复合材料力学与耐磨性能的影响,利用扫描电子显微镜(SEM)观察复合材料拉伸断面的微观结构,探讨其增强机理.结果表明:纳米SiN4或SiC与Al2O3混合填料均能使PTFE复合材料的硬度和耐磨性提高,且填充Si3N4/Al2O3的PTFE复合材料的硬度、拉伸性能、冲击强度和耐磨性均优于填充SiC/Al2O3的,其中5%Si3N4与Al2O3混合填充的PTFE复合材料有较好的综合性能.微观分析表明:Si3N4/Al2O3在PTFE基体中分散性较好,说明Si3N4与Al2O3具有较好的协同作用.     

SiO2用量对单分散聚脲多孔微球的影响

通过沉淀聚合,以异佛尔酮二异氰酸酯(IPDI)为单体,质量比为3:7的水与丙酮的混合溶液为溶剂,Si O2纳米颗粒为模板制备Si O2/聚脲复合微球,用Na OH溶液刻蚀掉Si O2后得到聚脲多孔微球。固定IPDI用量,改变模板Si O2纳米颗粒的用量制取聚脲多孔微球,用扫描电子显微镜观察微球的形貌,并对聚脲多孔微球的粒径、单分散性进行了测算。结果表明,不加Si O2纳米颗粒制得的实心聚脲微球粒径不均一,加入Si O2纳米颗粒后,制得的聚多孔脲微球的粒径增大,单分散性提高。     

纳米SiO_2杂化粒子的制备及其性能研究

以异佛尔酮二异氰酸酯（IPDI）与纳米SiO2表面Si—OH基团进行反应,制备了表面含—NCO基团的功能化纳米SiO2粒子,进一步用丙烯酸羟乙酯（HEA）对剩余—NCO基进行封端,制备出纳米SiO2/丙烯酸酯粒子,并用红外光谱（FI-IR）、热失重（TGA）、扫描电镜（SEM）等对改性前、后纳米SiO2的分散性进行表征。结果表明,IPDI和HEA均成功地以化学键形式接枝到纳米SiO2表面,接枝率为46.80%;改性纳米SiO2的分散性显著提高,团聚现象明显改善;将不同含量纳米SiO2杂化材料加入紫外光固化涂料中,同比加入未改性纳米SiO2的涂料,改性后的纳米SiO2在使涂料获得较低黏度和较快CC转化率的同时,可以显著地提高固化膜的硬度。     

Surface modification of nanosilica with acrylsilane-containing tertiary amine structure and their effect on the properties of UV-curable coating

In order to improve the dispersion of nanosilica and the mechanical properties of UV-curable coating, nanosilica was modified with acrylsilane-containing tertiary amine structure, which was synthesized by the Michael addition reaction between 3-aminopropyl triethoxysilane and tripropylene glycol diacrylate. The prepared acrylsilane was characterized by ¹H NMR, ¹³C NMR, and FTIR. The modified nanosilica was characterized by FTIR, TGA, and SEM. The TGA analysis showed that the grafting percentage of acrylsilane based on nanosilica was 72.4 wt%. The SEM results showed that the agglomeration of nanosilica was reduced and the dispersion was improved due to the acrylsilane modification. The viscosities of UV-curable coatings with modified nanosilica were determined and it was found that the viscosities of the coatings decreased in comparison with the viscosities of coatings with unmodified nanosilica. The photo-DSC results indicated that both nanosilica and modified nanosilica also decreased the UV-curing speed and final percentage conversion, while the conversion of the coatings containing modified nanosilica was faster than that with unmodified nanosilica owing to the tertiary amine structure and acrylate structure on the surface of the modified nanosilica.     

Surface modification of nanosilica with 3-mercaptopropyl trimethoxysilane and investigation of its effect on the properties of UV curable coatings

This paper describes surface modification of commercial nanosilica with 3-mercaptopropyl trimethoxysilane (MPTMS) and its effect on the properties of UV curable coatings. The mercapto groups were grafted onto nanosilica surface by a condensation of the surface Si–OH with the hydrolysized Si–OH of MPTMS. Fourier transform infrared spectroscopy, thermal gravimetric analysis, and particle size distribution were employed to characterize nanosilica and modified nanosilica. It was demonstrated that the mercapto groups were successfully grafted onto the nanosilica surface with the grafting ratio of 16.8% and the mercapto groups content of 0.9 mmol/g. The dispersion and self-aggregation of nanosilica in UV curable coatings were improved significantly. The photopolymerization kinetics of UV curable coatings, containing various amounts of nanosilica and modified nanosilica, were evaluated by the photo differential scanning calorimetry technique. This indicated that nanosilica both before and after modification decreased UV curing speed and ultimate percentage conversion; however, in comparison with the coatings containing unmodified nanosilica, the coatings containing modified nanosilica exhibited higher curing speeds and conversion ratios. It can be ascribed that the mercapto groups on the nanosilica surface reduced oxygen inhibition during the UV curing process via the thiol–ene click reaction. The mechanical properties of UV curable coatings were also compared.     

聚氨酯丙烯酸酯/SiO_2纳米杂化涂层的制备及其性能研究

采用不同相对分子质量的聚乙二醇(PEG-200、400、600)分别与六亚甲基二异氰酸酯(HDI)反应合成预聚体,再以此预聚体对纳米SiO2进行表面接枝改性,制备了聚氨酯改性纳米SiO2;将改性纳米SiO2分散到聚氨酯丙烯酸酯(PUA)中光固化制备了PUA/SiO2纳米杂化涂层。讨论了PEG相对分子质量对PUA/SiO2纳米杂化涂层的耐热性能和力学性能的影响,并以FT-IR、差示扫描量热法(DSC)等进行表征。结果表明,改性后的纳米SiO2粒子优化了PUA树脂的性能,且以PEG-400与HDI合成的预聚体来改性纳米SiO2用于制备的PUA/SiO2纳米杂化涂层具有较好的耐热性和抗冲击性。     

Preparation and properties of polymerizable silica hybrid nanoparticles with tertiary amine structure

To increase the photopolymerization rate and improve the properties of UV coatings, polymerizable silica hybrid nanoparticles with tertiary amine structure were prepared. Organic compound with isocyanate group was first grafted onto the surface of nanosilica by reaction of nanosilica with isophorone diisocyanate, then the nanosilica bearing isocyanate group reacted with N,N-di(3-propionic acid, 1,4,7-trimethyl-3,6-dioxaoctane-8-yl acrylate, ester) ethanolamine synthesized from tripropylene glycol diacrylate and ethanolamine. The preparation was characterized by ¹H nuclear magnetic resonance (NMR) and Fourier transform infrared spectrometry (FT-IR). Thermogravimetric analysis (TGA) showed that the organic compounds grafted onto the silica decomposed from 256 °C to 650 °C and the grafting percentage based on nanosilica was 105%. The morphology analysis of nanosilica and modified silica by field-emission scanning electron microscopy (FE-SEM) indicated that the silica kept nanosized scale after modification, while the nanosilica dispersion was improved and formation of agglomerates unlikely. Determination of viscosities of coatings with modified nanosilica, it was found that viscosities of the coatings decreased in comparison with the viscosities of coatings with unmodified nanosilica. Compared with pure organic coating, the photopolymerization rate of coatings were faster when modified nanosilica was used from 1 wt% to 5 wt%, but slower when the loadings of modified nanosilica was 7 wt% because co-initiating effects of tertiary amine compound grafted on nanosilica counterbalanced the effects of UV scattering by silica on photopolymerization rate. The hardness and abrasive resistance of cured films also increased and improvement degree was different when the various amounts of modified nanosilica were used.     

纳米二氧化硅粉体的表面改性研究进展

简介了纳米二氧化硅的表面改性方法；重点介绍了国内外纳米二氧化硅的表面改性方法及其对材料性能的影响；指出了纳米二氧化硅在聚合物基复合材料中的应用；展望了其发展前景。     

Unique behavior of in-situ generated nanosilica particles on physico-mechanical properties of fluoroelastomer

Fluoroelastomer (FKM) rubber containing different weight percentage of in-situ generated nanosilica particles have been prepared by sol-gel method using tetraethoxysilane (TEOS) as precursor and n-butyl amine as catalyst. FKM rubber with precipitated silica particles have also been prepared to compare the effect of in-situ generated nanosilica particles and precipitated silica particles on the physico-mechanical properties of FKM rubber. It is interesting to note that the FKM rubber containing in-situ generated nanosilica particles display excellent tensile stress-strain properties, rheological properties and thermal properties in comparison to the FKM rubber containing precipitated silica particles. The better performance of the in-situ generated nanosilica particles has been attributed to the good dispersion of in-situ generated nanosilica particles in FKM rubber matrix when compared to the precipitated silica particles. The fourier transform infrared (FTIR) spectroscopy clearly confirms the existence of chemical interaction between the FKM rubber chains and the in-situ generated nanosilica particles which leads to the good dispersion of the nanosilica particles in the rubber matrix. Strain sweep studies confirm the presence of more rubber-filler interaction in FKM rubber filled with in-situ generated nanosilica particles. On the other hand, strain sweep studies confirm the presence of more filler-filler aggregation in FKM rubber filled with precipitated silica particles. The dispersion of the in-situ generated nanosilica particles and precipitated silica particles in the surface and bulk of FKM rubber has been studied by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Selected samples have been cured to understand the effect of curing on the efficiency of in-situ generated nanosilica particles and precipitated silica particles on the physico-mechanical properties of FKM rubber.     

纳米二氧化硅的结构及表面改性对橡胶复合材料性能影响的研究进展

分析了纳米SiO_2结构及表面改性对其填充橡胶复合材料性能的影响,对比了不同表面改性方法对SiO_2增强效果的影响,指出基于良好分散性的适度结构化和高效功能化表面改性是提高SiO_2增强橡胶复合材料性能的重要因素.简要介绍了纳米SiO_2在橡胶复合材料中的应用研究现状.     

Morphology and crystallization behavior of PCL/SAN blends containing nanosilica with different surface properties

Morphology and crystallization behavior of poly(?‐caprolactone) (PCL) in its 80/20 blends with poly(styrene‐co‐acrylonitrile) (SAN) containing hydrophobic or hydrophilic nanosilica was investigated. It was found that hydrophilic nanosilica displayed a more significant refinement effect on co‐continuous morphology of PCL/SAN blends than hydrophobic nanosilica for its selective distribution within the PCL matrix but closer to the two‐phase interface. Ring‐banded spherulites were observed in both kinds of nanosilica‐filled blends, the periodic distance of which decreased with increasing nanosilica content. Hydrophilic nanosilica reduced the dependence of the periodic distance of ring‐banded spherulites on the crystallization temperature more efficiently than hydrophobic nanosilica. Furthermore, crystallization process of PCL/SAN blends filled with hydrophobic nanosilica was suppressed as the restriction effect of nanosilica on the crystal growth always outweighed their heterogeneous nucleation effect. In contrast, low content of hydrophilic nanosilica (≤1 wt %) were more likely to exhibit growth restriction effect rather than nucleation effect, whereas heterogeneous nucleation effect of higher content of hydrophilic nanosilica (>1 wt %) dominated over growth restriction effect on facilitating the crystallization behavior. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44157.     

纳米SiO2对石灰基材料性能影响研究进展

作为一种应用广泛的无机纳米材料,纳米SiO2颗粒尺寸小、比表面积大、表面吸附性强,在改性石灰早期强度低和耐久性方面效果显著.综述了纳米SiO2对石灰基材料力学性能、耐久性以及改性机理等方面的研究进展,并基于上述综述提出了纳米SiO2改性石灰基材料当前存在的问题,结合纳米SiO2改性石灰的应用情况,展望了该类材料未来的发展方向.