Dielectric Behavior of BaTiO_3/ PVDF Nanocomposites In-situ Synthesized by the Sol-Gel Method

1　IntroductionFerroelectricceramic polymercompositesconsistingofferroelectricceramicpowderembeddedinapolymermatrixhaveattractedmuchattentionsincetheycombinetheexcellentferroelectricpropertiesoftheceramicsandtheflexiblemechanicalpropertiesofthepolymer[1] …     

Dielectric Behavior of BaTiO3／ PVDF Nanocomposites In-situ Synthesized by the Sol-Gel Method

BaTiO3/ PVDF nanocomposites were prepared via in-situ growth of nanosized BaTiO3 particles in PVDF matrix by using the sol-gel method. The present elements of BaTiO3/ PVDF nanocomposites were analyzed by an electron probe X-ray microanalyser. Nanosized BaTiO3 grown in the composite films was characterized by an X-ray diffractometer and a transmission electron microscope, and the dielectric properties of the composite films were measured. The distribution of BaTiO3 nanoparticles in-situ grown in the PVDF matrix was examined using a scanning electron microscope.     

BT/PANI/PVDF复合材料的制备及介电性能

为提高电介质材料的介电性能,采用原位聚合的方法制备了BT/PANI复合功能体,以其为功能相,制备了BT/PANI/PVDF三相复合材料.采用红外光谱法和X射线衍射法对BT/PANI复合功能体的结构进行了表征,采用扫描电子显微镜和阻抗分析仪对BT/PANI/PVDF三相复合材料的微观形貌和介电性能进行了表征.分析了BT/PANI/PVDF体系中的极化方式,并以此为基础,对介电性能随频率的变化规律进行了解释.结果表明:在BT/PANI/PVDF三相复合体系中,功能相BT/PANI被均匀包覆在聚合物基体中,得到了介电性能较好的BT/PANI/PVDF三相复合材料.     

PbTiO3/PVDF复合材料介电性能及压电性能研究

实验制备了 Pb Ti O3/ PVDF复合材料 ,测试了频率对复合材料介电性能的影响 ,并分析了 Pb Ti O3的体积分数与复合材料介电性能的关系 ;研究了复合材料的压电性能 ;并对样品微观形态进行了分析。     

PU/PVDF 基复合材料的制备及介电性

以聚氨酯(PU)和聚偏氟乙烯(PVDF)为基体,以羟基化碳纳米管(MCNTs-OH)为填料,通过溶液共混法制备了PU/PVDF基复合材料。利用扫描电子显微镜对复合材料的微观形貌进行了表征,利用宽频介电与阻抗谱仪对复合材料的导电性和介电性能进行了测试。结果表明,在MCNTs-OH质量分数为2%, PU/PVDF质量比为1:1时,MCNTs-OH更倾向于分散在PU基体中;其在1.15 kHz的电导率达到最小值,只有78.5 nS/m;虽然该复合材料在频率1.15 kHz下的介电常数最低,但其数值仍高达393.08,而且其介电损耗也最小,低至0.31,具有良好的介电性能。     

Preparation and Characterization of Multi Shape ZnO/PVDF Composite Materials

Two different morphologies of ZnO(lotus-shaped, rod-shaped) and ZnO/PVDF composite materials were prepared. The morphologies of ZnO and composite materials were characterized by scanning electron microscopy(SEM) and transmission electron microscopy(TEM). Fourier transform infrared spectroscopy(FT-IR), thermal gravimetry(TG), and X-ray diffraction(XRD) were also used to characterize the chemical structures and phase composites of ZnO and ZnO/PVDF composite materials. Breakdown voltage, dielectric constant and dielectric loss of ZnO/PVDF composite materials were also tested. Microstructure analysis showed that ZnO nanoparticles dispersed uniformly in the matrix. And the dielectric constant expresses a significantly improvement while the dielectric loss and breakdown voltage expresses no significant change. Moreover, dielectric constant keeps an improvement tendency with increasing content of ZnO.     

高介电聚偏氟乙烯/聚苯胺复合材料的制备及表征

采用溶液共混法制备了高介电聚偏氟乙烯/聚苯胺复合材料,并对复合材料的微观结构、热稳定性和介电性能进行了表征和分析。结果表明:聚苯胺(PANI)在聚偏氟乙烯(PVDF)基体中分散得比较均匀,当质量分数w(PANI)达到10%时,大部分还是独立分散于PVDF基体中,只形成了少量渗流簇;虽然在PVDF中加入PANI会使复合材料的热稳定性变差,但PANI的加入有利于提高复合材料的介电常数。当w(PANI)8%时,复合材料在103Hz时的介电常数随PANI的增加而小幅增加;当w(PANI)由8%提高到10%时,复合材料的介电常数由8%时的57.7突跃至10%时的1 140。对复合材料的介电损耗来说,当w(PANI)8%时,介电损耗较低,但当w(PANI)由8%提高到10%时,介电损耗从1.07增加至12.2。     

聚吡咯/钛酸钡/聚偏氟乙烯复合材料的制备及性能

以聚偏氟乙烯(PVDF)为基体,聚吡咯(PPy)和钛酸钡(barium titanate,BT)为填料,通过溶液共混法制备了不同PPy质量分数的PPy/BT/PVDF三相复合材料,并对复合材料的微观形貌、结构和介电性能进行表征和分析.结果表明,PPy和BT大多均匀分散在聚合物基体中,加入PPy对PVDF的结晶影响较小;...     

CB填充PVDF复合材料导电网络形成的动力学研究

以低结构碳黑(LCB)和高结构碳黑(HCB)作为填料,聚偏氟乙烯(PVDF)作为基体,制备了PVDF/CB导电复合材料.将复合材料以高于PVDF熔点的温度进行等温热处理,实时监测电阻率随时间的变化,研究PVDF/CB体系导电网络形成的动力学过程.结果发现,电阻率-时间曲线呈现出一定的自相似性,即在达到某一临界时间tp时电阻率迅速下降,而且随着热处理温度的升高和CB含量的增加,体系的tp值减小.从tp与热处理温度的Arrhenius关系曲线可以得到PVDF/LCB和PVDF/HCB体系导电网络形成的活化能分别为65 kJ/mol和71 kJ/mol.提出了一个修正的热力学渗流模型预测PVDF/CB体系的tp,理论预测值与实验结果基本吻合.     

PA11/PVDF合金材料的电性能研究

采用PA11和PVDF两种聚合物基体，通过模压工艺制备了PA11/PVDF合金材料，研究了合金材料的介电性能与压电性能。通过XRD和SEM测试对样品的微观形态进行了研究。     

银/聚偏氟乙烯电介质复合材料性能研究

采用溶液共混法制备银(Ag)/聚偏氟乙烯(PVDF)复合材料,研究了Ag粉体积分数及粒径对复合材料介电性能、击穿场强等的影响。结果表明,复合材料的介电常数随填料的体积分数的增加而增大,当Ag粉体积分数为17%时最佳,之后介电常数开始下降。在Ag粉体积含量相同条件下,添加小粒径Ag粉比大粒径Ag粉更有利于提高复合材料介电性能。X射线衍射分析结果表明,Ag在复合材料制备过程中无分解及氧化,适量填充Ag粉有助于复合材料击穿场强的提高。     

The Dielectric Properties and Preparation Method of BaTiO3/PVDF 0-3 Composites

A series of 0-3 composties of the polyvinylidene fluoride (PVDF) and BaTiO3 was prepared,BaTiO3 was modified with titanate coupling agent .The dielectric properties and the interfacial interaction of composites by different preparation methods were examined and compared,The result shows that the relaive dielectric constant ε of the composite prepared in solution has a maximum value at about 70% weight fraction of BaTiO3 and the dielectric loss tanδ increases rapidly when the fraction exceeds 70%, For the composite preared in melt, the relative dielectric constant ε almost raches a maximum value at about 60% weght fraction of BaTiO3 and the dielectric loss is comparatively lower,The deielectric proerties of composites ore improved by using a coupling aent.     

聚偏氟乙烯、水泥和导电填料复合材料的电性能

采用先干混接着双辊塑炼最后高温模压的方法，成功制备了聚偏氟乙烯(PVDF)、水泥和Ti3SiC2或石墨导电复合材料，测量了电导率，并借助扫描电镜表征了复合材料的微观结构。结果表明：聚偏氟乙烯、水泥和石墨填料复合材料比聚偏氟乙烯、水泥和Ti3SiC2填料复合材料的电导率要高，能满足其用于燃料电池双极板的要求，并具有一定的自增湿功能。     

热处理PZT对PZT/PVDF复材电性能的影响

用高温处理PZT陶瓷粉末与PVDF制成压电复合材料,研究了高温处理PZT对复合材料的微观结构、极化特性、压电和介电性能的影响．结果表明：高温处理PZT制备的复合材料孔隙少,其剩余极化明显提高,提高了复合材料的压电系数和介电常数。     

Comparison of PVDF porous membranes modified by two different methods using composite nano-particles

To improve the hydrophilicity and anti-fouling performance in water treatment,both entrapped method and deposited method were used to modify polyvinylidene fluoride(PVDF)porous membrane with composite Al2O3/TiO2 nano-particles.Neat PVDF membrane was prepared and its property was also compared with that of the modified membranes.Membrane permeation flux and anti-fouling performance were measured using a membrane cell.The contact angle between water and membrane surface was detected in order to denote the membrane hydrophilicity.Membrane morphology and surface structure were examined by atomic-force microscopy(AFM)and scanning electron microscopy(SEM).Experimental results showed that modified membranes had higher permeation fluxes than that of the neat PVDF membrane.The addition of nano-particles altered membrane surface morphology and increased surface roughness.Due to the hydrophilicity of nano-particles,however,the membrane anti-fouling performance was improved instead of worsened.The entrapped membrane exhibited better anti-fouling performance than the deposited membrane and the neat membrane.     

纳米Al2O3改性PVDF超滤膜的制备及其抗污染性

为改善聚偏氟乙烯(PVDF)超滤膜的水通量和抗污染性能,以无机纳米氧化铝粒子作为添加剂与PVDF共混,采用相转换法流延成膜.用接触角测定仪测得膜与水的接触角用以表征膜的亲水性的变化;用扫描电镜(SEM)和透射电镜(TEM)观察膜的表面孔分布和断面孔的结构及纳米颗粒在膜中的分散情况;采用万能电子试验机(W-56)强度测定仪测定膜的机械性能;利用杯试超滤装置对改性膜的抗污染性能进行研究,并对污染膜上的污染物进行了气相色谱和质谱分析.结果表明,纳米Al2O3的加入量(质量百分比)为2%时,改性膜具有较好的水通量、强度和抗污染性能;纳米Al2O3的加入没有改变膜的微观结构.改性膜在保持PVDF有机膜原有特性的基础上,通过改善PVDF膜的表面亲水性而使其通量和抗污染性能得到增强.     

原位生成ZDMA对丁腈橡胶-金属粘接性能的影响

在丁腈橡胶（NBR）混炼过程中加入氧化锌（ZnO）与甲基丙烯酸（MAA）,在橡胶基体中原位生成甲基丙烯酸锌（ZDMA）,研究ZDMA对丁腈橡胶-金属粘接性能的影响.实验结果表明：采用原位生成的ZDMA能明显提高橡胶与金属的粘接性能,且优于直接加入ZDMA.粘接力随ZDMA用量的增加而增加,其最大粘接力为244.83 N.     

铌铁酸锶-钛酸铅铁电固溶体的合成与性能研究

通过铌铁矿预合成法制备了(1-x)Sr(Fe1/2Nb1/2)O3-xPbTiO3(SFN-PT)铁电陶瓷。XRD测量表明,合成的SFN-PT陶瓷为纯钙钛矿结构。随着PbTiO3(PT)摩尔分数的增加,SFN-PT陶瓷的晶体结构从三方相向四方相转变,其介电响应也从弥散的宽峰变得比较尖锐,并伴随着介电常数峰值温度(Tm)的升高。少量的MnO2或Li2CO3掺杂能有效地降低SFN-PT陶瓷的介电损耗。SFN-PT陶瓷呈现典型的P-E电滞回线,但是剩余极化强度较小,少量的MnO2或Li2CO3掺杂能明显地降低矫顽场、增大剩余极化强度。SFN-PT陶瓷的压电应变常量d33较小,随着组分的不同,d值在10～22pC/N之间变化。     

二氧化硅改性环氧树脂胶黏剂性能研究

采用聚氨酯增韧环氧树脂,并利用有机化的纳米SiO2为改性剂制备纳米改性环氧树脂胶黏剂.利用扫描电子显微镜( SEM)观察无机纳米粒子在聚合物基体中的分散性及复合材料的断面形貌,结果表明无机纳米粒子在复合材料中分散性良好,而且聚氨酯在环氧树脂基体中形成了“孔洞结构”.采用电子拉力机、TGA以及介电谱仪等方法测试了复合材料...     

PZT/PVDF压电复合材料微观结构与性能研究

采用溶液混合法制备 PZT/ PVDF压电复合材料。首先用固相法制备出适合溶液混合的 PZT陶瓷粉末 ,并且通过陶瓷粉末对 PVDF的吸收量选择乙醇为 PVDF的溶剂进行混合 ,然后烘干制备出 PZT/ PVDF复合粉末 ,再成型极化。实验结果表明这种复合方法提高了 PZT陶瓷颗粒在 PVDF有机基体中的分散度 ,使制得的材料内部均匀 ,结构致密 ,从而提高了 PZT/ PVDF压电复合材料的压电和介电性能。