论文总字数：21488字

摘 要

传统的无机介电材料（介电陶瓷）应用广泛，优势明显。但由于这类材料力学性能较差，且不易加工，在应用方面受到一些限制。因此，通常以聚合物为基体，在其中加入具有较高介电常数的无机粉体或是有机导电材料通过合适的加工方法，制备兼具两者优势的功能复合材料，来拓展介电材料的应用领域。通过钛酸钡（BaTiO₃）与丁腈橡胶（NBR）的复合可以制备出兼具两者优势的聚合物基复合介电材料，但其介电损耗也相对较高。钛酸锶（SrTiO₃）常温下为顺电相，介电常数小于BaTiO₃，但介电损耗极低。本课题选用丁腈橡胶N250S（丙烯腈含量20 wt%）作为基体，将不同比例的BaTiO₃、SrTiO₃与N250S复配共混制备低介电损耗的复合材料。此外，顺电相材料SrTiO₃的掺杂可以改变BaTiO₃的居里温度。通过固相法制备钛酸锶钡（Ba_xSr_1-xTiO₃），调节Ba/Sr比例以改变其居里温度(Tc)，与N250S共混，使复合材料能够在常温下具有较高的介电常数。并在室温条件研究宽频谱下介电性能的变化。

本课题采用X射线衍射分析仪(XRD)，阻抗分析仪，傅里叶红外光谱仪(FTIR)，高阻计，电子万能实验机，扫描电子显微镜(SEM)等对材料进行测试和表征。实验结果表明，双-（γ-三乙氧基硅基丙基）四硫化物（KH845-4）作为一种硅烷偶联剂，成功的包覆在了无机粉体颗粒表面，这样可以改善无机粉体在聚合物中的分散性，同时对NBR这样一种非自补强型橡胶有所补强。在与BaTiO₃、SrTiO₃复配共混体系中，SrTiO₃ 的加入可在一定程度上使力学性能有所提升。另一方面SrTiO₃有着低介电损耗的优势，在加入SrTiO₃之后介电损耗因子有所降低。在与Ba_xSr_1-xTiO₃共混体系中，当x=7时，介电常数最高，且损耗因子无增加趋势。

关键词：丁腈橡胶 钛酸钡 钛酸锶钡 表面改性 介电常数

Preparation and Properties of High Dielectric Nitrile Rubber Functional Composites

Abstract

The traditional inorganic dielectric materials (dielectric ceramics) are widely used, and the advantages are obvious. However, because the poor mechanical properties of these materials, they are difficult to process and limited in the application. Therefore, it is common to use a polymer as a matrix in which an inorganic powder or an organic conductive material having a higher dielectric constant is added by a suitable processing method to prepare a functional composite material having both advantages to expand the dielectric material application areas. The polymer-based composite dielectric materials with high dielectric constant, excellent processability and excellent oil resistance can be prepared by the combination of barium titanate (BaTiO₃) and acrylonitrile-butadiene rubber(NBR), but the dielectric loss is also relatively high. Strontium titanate (SrTiO₃) at room temperature for the cis phase, the dielectric constant is less than BaTiO₃, but the dielectric loss is very low. In this study, nitrile rubber N250S (acrylonitrile content 20 wt%) was used as the matrix, and the composite materials with low dielectric loss were prepared by mixing BaTiO₃, SrTiO₃ and N250S in different proportions. In addition, the doping of the cis phase material SrTiO₃ can change the Curie temperature of BaTiO₃, prepare barium strontium titanate (Ba_xSr_1-xTiO₃) by solid phase method, adjust the Ba / Sr ratio to change its Curie temperature (Tc), and N250S was mixed, so that the composite materials can have a high dielectric constant at room temperature. And the change of dielectric properties under broad spectrum was studied at room temperature.

The materials were tested and characterized by X-ray diffraction (XRD), impedance analyzer, Fourier transform infrared spectroscopy (FTIR), high resistance meter, electronic universal testing machine and scanning electron microscopy (SEM). The experimental results show that bis (γ-triethoxysilylpropyl) tetrasulfide (KH845-4) is successfully coated on the surface of the inorganic powder particles as a silane coupling agent, which can improve the inorganic Powder in the polymer dispersion, while the NBR such a non-self-reinforced rubber has been reinforced. In the complex blends with BaTiO₃ and SrTiO₃, the addition of SrTiO₃ can improve the mechanical properties to a certain extent. On the other hand, SrTiO₃ has the advantage of low dielectric loss, after the addition of SrTiO₃ dielectric loss factor is reduced. In the blends with Ba_xSr_1-xTiO₃, when x = 7, the dielectric constant is the highest, and the loss factor does not increase.

Key words: acrylonitrile-butadiene rubber; barium titanate; barium strontium titanate; surface modified; dielectric constant

目 录

摘 要 I

Abstract II

第一章 绪论 1

1.1 课题背景 1

1.2 国内外研究进展 1

1.3 理论部分 3

1.3.1 NBR简介 3

1.3.2 BaTiO₃简介 3

1.3.3 SrTiO₃简介 4

1.3.4 Ba_xSr_1-xTiO₃简介 4

1.3.5 硅烷偶联剂简介 4

1.3.6 聚合物的介电性能 4

1.4 本课题工作内容与方法 5

第二章 实验部分 7

2.1 实验原材料 7

2.2 实验仪器及设备 7

2.3 实验配方 8

2.4 样品制备 8

2.4.1 BT、ST、B_xS_1-xT粉体表面处理 8

2.4.2 混炼胶和硫化胶制备 8

2.5 表征及性能测试 8

2.5.1 B_xS_1-xT粉体XRD表征 9

2.5.2 BT、ST、B_xS_1-xT粉体粒径的表征 9

2.5.3 傅里叶红外光谱分析 9

2.5.4 两相溶剂分散实验 9

2.5.5 接触角测试实验 9

2.5.6 硫化曲线测试 9

2.5.7 力学性能测试 9

2.5.8 体积及表面电阻率测试 10

2.5.9 耐油性测试 10

2.5.10 介电性能测试 10

第三章 结果与讨论 11

3.1 B_xS_1-xT粉体的表征 11

3.2 BT、ST、BST粉体粒径的表征 11

3.3 粉体改性效果表征 12

3.4 硫化曲线分析 14

3.4 力学性能分析 15

3.5 体积及表面电阻率分析 16

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