固体含量对PI/SiO2纳米杂化薄膜聚集态结构的影响

以均苯四甲酸二酐(PMDA)和4,4'-二氨基二苯醚(ODA)为有机单体,正硅酸乙酯(TEOS)为无机前驱体,制备了SiO2含量一定,PAA杂化胶液固体含量不同的PI/SiO2纳米杂化薄膜.利用傅立叶变换红外光谱(FT-IR)、原子力显微镜(AFM)、广角X射线衍射仪(WAXD)分析了PAA杂化胶液固体含量对PI/SiO2纳米杂化薄膜聚集态结构的影响.研究结果表明,当PAA杂化胶液固体含量为10%～20%时,团聚的SiO2粒子粒径尺寸随固体含量增加而增加,有机相与无机相界面变清晰,两相作用减弱.随固体含量增加,PI分子链有序度降低,但固体含量对PI分子链有序度的影响很小.     

聚酰亚胺/TiO2纳米杂化膜的制备及表征

将间苯二胺，2,2’-双三氟甲基-4,4’-联苯二胺和2,3,3’,4’-联苯四甲酸二酐反应得到可溶性聚酰亚胺(KPI)，再把KPI与TiO₂溶胶共混，经流延制膜并热亚胺化后得到PI/TiO₂纳米杂化膜。通过红外光谱、扫描电镜、透射电镜和能谱仪对PI/TiO₂纳米杂化膜的成分、结构和形态进行表征。结果表明，TiO₂已成功引入PI基体中，并以纳米尺寸均匀分布。热重分析和拉伸实验表明，TiO₂的引入提高了PI/TiO₂纳米杂化膜热的稳定性和力学性能。紫外-可见光谱表明，TiO₂的掺入并不影响PI/TiO₂纳米杂化膜的光学透过率。分别研究了PI/TiO₂纳米杂化膜对亚甲基蓝和刃天青的光催化活性。24 h内，PI/TiO₂(5%)纳米杂化膜对亚甲基蓝的降解率高达96.40%，说明PI/TiO₂纳米杂化膜具有极强的光催化活性，能起到光催化效果的主要原因是杂化...     

纳米Al2O3的晶型对聚酰亚胺杂化薄膜性能的影响

将经偶联剂处理的纳米Al2O3粉体,借助超声波以一定方式均匀分散于聚酰胺酸溶液中,制备出Al2O3不同晶型、不同含量的PI/纳米Al2O3杂化薄膜,并对杂化薄膜微观形貌、聚集态结构、光透过率、热稳定性、电击穿场强进行研究,分析Al2O3晶型和含量对PI/纳米Al2O3杂化薄膜的结构和性能的影响.结果表明:PI/纳米Al2O3杂化薄膜的热稳定性,电击穿场强均高于纯PI薄膜,且随着纳米Al2O3含量的提高热稳定性也随之提高,电击穿场强先升高后降低;填充Al2O3粉体的晶型对PI薄膜分子链堆积密度有较大的影响,导致添加不同晶型Al2O3的杂化薄膜性能的差异.     

偶联剂用量对聚酰亚胺杂化薄膜结构与性能的影响

用不同用量硅烷偶联剂处理纳米Al2O3粉体,并借助超声波以一定方式将其均匀分散于聚酰胺酸溶液中,制备出不同偶联剂用量的PI/纳米Al2O3杂化薄膜,并对该杂化薄膜的断面形貌、聚集态结构、热稳定性、力学性能、电击穿场强进行表征测试分析.结果表明,偶联剂用量对PI杂化薄膜的聚集态结构影响较小,但对无机纳米粒子在PI基体中的分散状态有较大影响,当偶联剂AE3012的用量为无机粒子质量分数的4%时,该PI杂化薄膜的热稳定性、力学性能、电击穿场强均最高.     

偶联剂对聚酰亚胺／纳米Al2O3杂化薄膜结构与性能的影响

将经不同种类硅烷偶联剂改性的纳米Al2O3粒子借助超声波以一定方式均匀分散于聚酰胺酸胶液中,制备聚酰亚胺/纳米Al2O3杂化薄膜,并对该杂化薄膜的微观形貌、分子链有序度、热稳定性、力学性能、电击穿场强进行表征与测试.结果表明,偶联剂种类影响杂化薄膜的分子链有序度,在使用4种偶联剂改性纳米Al2O3制备的PI杂化薄膜中,使用偶联剂KH550的Pl杂化薄膜的热稳定性、力学性能最好;使用AE3012的PI杂化薄膜的电击穿场强最高.     

纳米杂化PI薄膜击穿孔区形貌及元素分布

无机纳米杂化聚酰亚胺(PI)薄膜具有优良的耐电晕特性,通过观察击穿孔区形貌研究薄膜击穿机理及纳米颗粒的作用,利用SEM观察阶梯式升压强电场击穿无机纳米杂化PI薄膜孔区形貌,能谱仪测试孔区附近元素分布.研究表明:杂化薄膜严重破坏区域仅局限在孔洞附近10～50 μm范围内,随半径增加,其表面由颗粒大小不均匀、表面粗糙不平,逐渐过渡到颗粒均匀的微观结构状态;Cu含量逐渐减少,Au含量逐渐增加,正常区域电极表面没有损伤;氧化铝纳米颗粒在杂化薄膜中起到阻止电极破坏的作用,薄膜击穿机理属热击穿类型.     

表面改性纳米TiO2粒子杂化PI薄膜的制备与性能研究

采用硅烷偶联剂(γ-巯丙基三乙氧基硅烷)对纳米TiO2粒子进行表面处理,通过原位聚合和流延成膜法制备了不同TiO2含量的PI/TiO2杂化膜,研究了杂化膜的热性能、力学性能,并通过扫描电镜(SEM)和广角X衍射(WAXD)研究了杂化膜的微观形貌结构,同时也对杂化膜的接触角和介电常数(ε)进行了研究分析.结果表明,杂化膜较纯膜的热分解温度(T5％)降低,但平均热分解温度仍然高于520℃,且膜的尺寸稳定性得到了提高,即热膨胀系数( CTE)降低;表面形貌分析表明,1％～5％的表面改性纳米TiO2能较好地分散在PI膜里,杂化膜的介电常数(3.50左右)均高于纯膜的的介电常数(2.91),杂化膜的接触角随着TiO2含量的增加呈现先减少后增加的趋势.     

聚氨酯无机杂化材料研究进展及应用前景

介绍了聚氨酯无机杂化材料的性能,叙述了制备聚氨酯无机杂化材料的4种主要方法.重点对国内外聚氨酯无机杂化材料的研究现状进行了分析,对纳米SiO2和蒙脱土杂化的聚氨酯杂化材料进行了着重阐述,进而探讨了无机杂化材料在聚氨酯注浆材料中应用的可能性和今后发展前景.     

新型壳聚糖/DNS杂化材料的制备及对重金属Pb2+的吸附性能研究

在乙醚介质中,通过丁二酸酐与γ-氨丙基三甲氧基硅烷改性后的纳米SiO2(即可分散的纳米SiO2,简称DNS)反应,合成了羧基化的DNS,经过壳聚糖与羧基化的DNS脱水生成酰胺的过程,制备了壳聚糖/DNS杂化材料.通过红外光谱、扫描电镜和热重分析对杂化材料进行表征.研究了壳聚糖及杂化材料微粒吸附Pb2+时pH值、时间、用...     

有机-无机杂化纳米复合材料合成及性能测试

采用溶胶-凝胶法,以甲基三乙氧基硅烷(MTEOS)和正硅酸乙酯(TEOS)及纳米氧化硅为原料,成功制备了有机-无机杂化纳米复合材料及涂层.以X射线衍射(XRD)、富立叶红外光谱(FTIR)、扫描电子显微镜(SEM)和原子力显微镜(AFM)等手段研究了杂化材料的工艺与结构及性能的关系,并对涂覆于铝合金基体上的纳米复合材料涂层的防腐蚀性能进行了实验检测.结果表明,有机-无机杂化纳米复合材料涂层具有优良的抗腐蚀性能.     

纳米SiO2改性聚酰亚胺的研究进展

聚酰亚胺(PI)作为一种功能材料,具有良好的介电性、优良力学性能,已被广泛应用于航空航天及微电子领域,但其明显的吸水性和热膨胀性限制了其在高温和精密状态下的应用。纳米SiO2具有很低的热膨胀系数和较低的吸水性,非常适合于对PI的改性。介绍了纳米SiO2的生产原理、纳米SiO2／PI复合材料的制备方法、性能及其在气体分离膜、光电材料、摩擦材料及包装材料方面的应用,并对这类材料的研究方向提出了自己的建议。     

Bionanocomposites: A New Concept of Ecological,Bioinspired, and Functional Hybrid Materials

Bionanocomposites represent an emerging group of nanostructured hybrid materials. They are formed by the combination of natural polymers and inorganic solids and show at least one dimension on the nanometer scale. Similar to conventional nanocomposites, which involve synthetic polymers, these biohybrid materials also exhibit improved structural and functional properties of great interest for different applications. The properties inherent to the biopolymers, that is, biocompatibility and biodegradability, open new prospects for these hybrid materials with special incidence in regenerative medicine and in environmentally friendly materials (green nanocomposites). Research on bionanocomposites can be regarded as a new interdisciplinary field closely related to significant topics such as biomineralization processes, bioinspired materials, and biomimetic systems. The upcoming development of novel bionanocomposites introducing multifunctionality represents a promising research topic that takes advantage of the synergistic assembling of biopolymers with inorganic nanometer‐sized solids.     

数字散斑相关方法测量聚酰亚胺无机纳米杂化材料的热膨胀系数

利用数字散斑相关方法计算在不同温度下聚酰亚胺无机纳米杂化膜的变形量,并以此计算出聚酰亚胺无机纳米杂化膜的热膨胀系数。实验中同时测量了掺杂有不同浓度粘土、云母和二氧化硅类无机物的聚酰亚胺薄膜的热膨胀系数,并对实验结果进行了分析。     

羟基磷灰石/淀粉基复合生物材料

淀粉基(starch-based)材料是一类重要的生物降解聚合物,羟基磷灰石(HA)是人体骨骼的主要成分,以淀粉基材料为基体、以HA为增强材料的HA/淀粉基复合材料是一类新型的复合生物材料,其具有良好的生物相容性,在骨修复领域具有巨大的应用潜力.初步对该复合材料进行了归类,并介绍了其制备工艺、性能和应用等方面的研究近况,指出改进复合工艺、采用纳米级HA增强并进行表面改性是其发展趋势.     

纳米磁靶向复合材料的研究进照

纳米磁靶向复合材料将纳米技术和磁靶向技术有机结合起来,借助纳米磁性材料的奇异特性,在肿瘤的磁靶向治疗领域具有很大的应用潜力而备受关注.介绍了纳米磁靶向复合材料的组成、制备及应用于肿瘤磁靶向治疗中的研究进展,并对其发展前景进行了展望.     

Synthesis and characterization of functional ladder-like polysilsesquioxane and their hybrid films with polyimide

Ladder-like polyphenylsilsesquioxane has been synthesized by a convenient two-step approach and then modified to ladder-like poly(nitrophenyl)silsesquioxane (LPNPSQ) and poly(aminophenyl)silsesquioxane (LPAPSQ) by nitration and reduction reaction. These ladder-like polysilsesquioxanes (LPSQs) were characterized by Fourier transform infrared, nuclear magnetic resonance and X-ray diffraction (XRD). The results confirm the ladder-like structures of LPSQs and suggest the decrease of regularity after the chemical modification. Then high performance polyimide/ladder-like polysilsesquioxane (PI/LPSQ) hybrid films have been prepared by incorporating synthetic LPSQs with different functional groups into PI matrix, respectively, using conventional techniques. The interfacial interactions between PI matrix and LPSQ were investigated with XRD and scanning electron microscopy. Then the thermal and mechanical properties of the hybrid films were studied using dynamic mechanical analysis and tensile tests. The results indicate that different functional groups in LPSQs have great effects on the interfacial interactions and the properties of the hybrids. Both LPNPSQ and LPAPSQ can be dispersed uniformly in PI matrix because of the physical or chemical interaction between functional groups and PI. With these strong interfacial interactions, PI/LPNPSQ and PI/LPAPSQ hybrid films show higher glass transition temperatures and better mechanical properties.     

Multiple Functionalities of Polyelectrolyte Multilayer Films: New Biomedical Applications

The design of advanced functional materials with nanometer‐ and micrometer‐scale control over their properties is of considerable interest for both fundamental and applied studies because of the many potential applications for these materials in the fields of biomedical materials, tissue engineering, and regenerative medicine. The layer‐by‐layer deposition technique introduced in the early 1990s by Decher, Moehwald, and Lvov is a versatile technique, which has attracted an increasing number of researchers in recent years due to its wide range of advantages for biomedical applications: ease of preparation under “mild” conditions compatible with physiological media, capability of incorporating bioactive molecules, extra‐cellular matrix components and biopolymers in the films, tunable mechanical properties, and spatio‐temporal control over film organization. The last few years have seen a significant increase in reports exploring the possibilities offered by diffusing molecules into films to control their internal structures or design “reservoirs,” as well as control their mechanical properties. Such properties, associated with the chemical properties of films, are particularly important for designing biomedical devices that contain bioactive molecules. In this review, we highlight recent work on designing and controlling film properties at the nanometer and micrometer scales with a view to developing new biomaterial coatings, tissue engineered constructs that could mimic in vivo cellular microenvironments, and stem cell “niches.”     

Photochromism in composite and hybrid materials based on transition-metal oxides and polyoxometalates

Photochromic materials are attractive and promising for applications in many fields. One subject in this area is to prepare and study the photochromism in composite or hybrid materials based on transition-metal oxides or polyoxometalates. Their properties not depend only on the chemical nature of each component, but also on the interface and synergy between them. Since the charge transfer plays a key role in the photochromism of these materials, it is very important to increase the charge (electrons, holes, and protons) interactions between the two components in either composites or hybrids. To realize this, one big challenge is to optimize the two components on a molecular or nanometer scale, which is closely relevant to the constituents, sample history (pre-treatment, preparation, and post-treatment), environment (humidity, presence of reducible or oxidizible matters, light-irradiation wavelength, intensity, time, etc.). Based on these, many novel composite or hybrid materials with improved photochromism, visible-light coloration, reversible photochromism, multicolor photochromism or, possibly, fast photoresponse, have been prepared during the last two decades or three. This may underscore the opportunity of using these composite and hybrid materials as the photonic applications. In present paper, we summarize thoroughly all the recent progress in these subjects.     

B_4C_P/PI聚酰亚胺复合薄膜耐高温及热中子辐照屏蔽性能研究

以耐高温型聚酰亚胺为基体,微米碳化硼(B_4C)为热中子吸收剂,采用粉体表面改性及超声湿混-热亚胺化成膜工艺成功制备了一系列B_4CP/PI聚酰亚胺复合薄膜,重点探讨了不同B_4C含量条件下复合薄膜的耐热性能和力学性能以及不同B_4C含量、不同复合薄膜厚度条件下复合材料的热中子屏蔽性能。研究表明:采用上述工艺,B_4C功能粒子在聚酰亚胺基体中可均匀分散;B_4CP/PI复合薄膜的耐热性随B_4C含量的增加显著提高,力学性能则呈相反趋势;所制备的B_4CP/PI复合薄膜表现出优异的热中子屏蔽性能,中子透射率I/I0随复合薄膜厚度增加及B_4C含量增加呈指数变化规律。据此,可通过材料结构设计,满足不同领域对该类耐高温中子防护材料的应用需求。     

The challenge of ceramic/metal microcomposites and nanocomposites

It is increasingly being recognized that new applications for materials require functions and properties that are not achievable with monolithic materials. The combination of dissimilar materials for these new applications creates interfaces whose properties and processing need to be understood before they can be applied commercially. In the present review paper we try to emphasize the important role and challenges of ceramic/metal micro/nanocomposites in the new technologies. In this respect we will study and review the exotic effects of metal particles embedded into matrix ceramics due to the dissimilar properties of the components, percolation laws, and the nature of the interfaces. From an electromagnetic point of view we have underlined the enormous enhancement of permittivity in the proximity of the percolation threshold, associated with an induced soft mode similar to para-ferroelectric transition. From a mechanical standpoint, the synergic effect of nanometer size, clustering addressed by the percolation theory and ceramic/metal interface features produces an unexpected enhancement in the hardness of the composite giving rise to superhard materials.