力敏和温敏导电硅橡胶的制备及其性能研究

发布时间：2018-04-01 04:21

  本文选题：导电橡胶　切入点：力敏效应　出处：《昆明理工大学》2015年硕士论文

【摘要】：导电橡胶属于导电高分子复合材料,是将导电填料均匀分散在高分子弹性体基体内,使其同时具有弹性和导电性的一种新型半导体功能材料。导电橡胶具有较好的力敏和温敏等性能,因此适合用于制备柔性触觉传感器的力敏器件和温敏器件。影响导电橡胶的力敏效应和温敏效应的因素很多,力敏机理与温敏机理虽然都是基于导电橡胶的导电机理,但其实质却不一样。本文阐述了导电高分子复合材料的导电机理；分析了基于导电通路理论和量子隧道效应理论的力敏机理和温敏机理；总结归纳了具有代表性的力敏和温敏数学计算模型；提出了新的导电硅橡胶制备工艺,为后续的实验研究打好基础；分别研究了橡胶基体材料的粘度以及组分、硫化剂、炭黑填充量以及改性材料添加剂等因素对导电硅橡胶的力敏效应和温敏效应的影响。本文分别从导电橡胶力敏效应和温敏效应两个方面进行了研究。提出了可以消除填料团聚结块并提高填料分散性的处理方法和利用硅烷偶联剂对填料粉末进行改性的新方式。确定了导电硅橡胶脱模后固化成型所需要的时间为12小时左右。提出了新的导电硅橡胶制备工艺,细化并且量化了制备导电硅橡胶原材料添加顺序、搅拌速度以及搅拌时间等制备参数,提高了导电填料的分散性,降低了渗流阈值(从6%下降到4%)。研究了基体材料的粘度以及组分、硫化剂、改性材料添加剂对导电硅橡胶的压阻特性、弛豫特性以及迟滞特性等力敏性能的影响。发现：(1)硅橡胶基体的粘度(在1500-10000 mPa.s范围内)越高,压阻特性越好,电阻弛豫时间越短,电阻迟滞特性系数越小；(2)双组分基体比单组分基体压阻特性曲线的光滑度好,电阻弛豫时间短,电阻迟滞特性系数小；(3)硅烷偶联剂可以作为硫化剂单独使用；(4)硅烷偶联剂Si-69与正硅酸乙酯并用作为硫化剂时,硫化时间短,压力敏感区间较大,压阻范围较大,电阻弛豫时间较短,且压阻曲线的规律性较好,导电硅橡胶的力敏效应较好；(5)提高硫化温度,能加快硫化速率,但对导电硅橡胶的内部结构产生不良影响,影响复合材料体系的稳定性；(6)添加多壁碳纳米管改性材料能显著增大导电硅橡胶的压阻范围,减小电阻弛豫时间,具有良好的力敏效应,在0-50N压力范围内可以作为柔性力敏传感器的力敏元件使用。研究了不同乙炔炭黑填充量对室温硫化导电橡胶温敏效应的影响。发现在渗流区间4%-12%范围内,当导电填料填充量较少,靠近4%渗流阈值时,导电橡胶呈现正温度系数效应；当导电填料填充量进一步增大,达到8%,处于高电阻区与导电区之间时,导电橡胶先呈现正温度系数效应,后呈现负温度系数效应,存在温度临界点80℃；当导电填料填充量较大,靠近导电区时,导电橡胶呈现负温度系数效应。导电乙炔炭黑填充量为4%的导电硅橡胶在20℃-120℃范围内具有良好的温敏效应,适合作为柔性温敏传感器的敏感器件。对于同一种室温硫化硅橡胶基体(粘度在1500-10000 mPa.s范围内),其粘度越小,导电橡胶表现出负温度系数效应越明显。在炭黑填充量为10%时,单组分制备得到的导电硅橡胶先呈现负温度系数效应,后呈现正温度系数效应；而双组分制备得到的导电硅橡胶的表现出一致性的负温度系数效应。
[Abstract]:The conductive rubber belongs to a conductive polymer composite material , which is a novel semiconductor functional material which uniformly disperses the conductive filler in the polymer elastomer matrix so as to simultaneously have elasticity and electrical conductivity .
The mechanism of force - sensitive mechanism and temperature - sensitive mechanism based on the theory of conductive path and quantum tunneling effect are analyzed .
In this paper , a representative force - sensitive and temperature - sensitive mathematical model is summarized .
The preparation technology of new conductive silicone rubber is proposed , which provides a good basis for the subsequent experimental research .
The effects of the viscosity and the components , vulcanizing agent , carbon black filling amount and the additive of modified materials on the force - sensitive and temperature - sensitive properties of the conductive silicone rubber were studied .
( 2 ) the two - component matrix is better than the single - component substrate pressure resistance characteristic curve , the resistance relaxation time is short , and the resistance hysteresis characteristic coefficient is small ;
( 3 ) the silane coupling agent can be used as a vulcanizing agent alone ;
( 4 ) When the silane coupling agent Si - 69 and ethyl orthosilicate are used as the vulcanizing agent , the vulcanizing time is short , the pressure sensitive interval is large , the pressure resistance range is large , the resistance relaxation time is short , and the regularity of the piezoresistive curve is good , and the force sensitivity effect of the conductive silicone rubber is good ;
( 5 ) the vulcanization temperature can be increased , the vulcanization rate can be accelerated , the internal structure of the conductive silicon rubber is adversely affected , and the stability of the composite material system is influenced ;
( 6 ) Adding multi - wall carbon nanotube modified material can significantly increase the piezoresistive range of conductive silicone rubber , reduce the relaxation time of resistance , and can be used as a force sensitive element of flexible force sensitive sensor in the range of 0 - 50N . It is found that the conductive rubber exhibits positive temperature coefficient effect in the range of 4 % -12 % of percolation range , when the filling amount of conductive filler is less , and near 4 % percolation threshold .
when the filling quantity of the conductive filler is further increased to reach 8 percent , the conductive rubber firstly presents a positive temperature coefficient effect when the conductive filler is positioned between the high resistance region and the conductive region , and then the negative temperature coefficient effect is presented , and the temperature critical point is 80 DEG C ;
The conductive rubber exhibits a negative temperature coefficient effect in the range of 20 鈩，

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