硅烷偶联剂改性SiC晶须/PVDF复合薄膜的制备及其介电性能研究  

Preparation and Dielectric Properties of Silane Coupling Agent Modified SiC Whisker/PVDF Composite Membrane

作　　者：许静 雷西萍[1] 韩丁[1] 刘戈辉 于婷 邢敏 XU Jing;LEI Xi-ping;HAN Ding;LIU Ge-hui;YU Ting;XING Min(Functional Materials Laboratory,College of Materials&Mineral Resources, Xi’an University of Architecture and Technology,Xi’an 710055,China)

机构地区：[1]西安建筑科技大学材料与矿资学院功能材料研究所,西安710055

出　　处：《硅酸盐通报》2018年第9期3028-3035,共8页Bulletin of the Chinese Ceramic Society

摘　　要：设计填料为半导体纳米晶须、基体为高分子聚合物是制备具有良好介电性能和力学性能材料的基本要求。首先利用化学改性法将不同硅烷偶联剂修饰在碳化硅晶须(SiC_w)表面,再利用溶液流延法制备改性SiC_w/聚偏氟乙烯(PVDF)复合薄膜。采用直接观察、FT-IR和热重分析对SiC_w的改性效果进行评价,通过SEM观察SiC_w在PVDF中的分布情况,并测试了该复合薄膜的介电性能随温度的变化情况。结果表明:利用本文的试验方法可成功将硅烷偶联剂引入到SiC_w表面;SEM结果显示,利用化学改性法可有效改善SiC_w的团聚问题,使其均匀分布在PVDF基体内;TGA结果表明,添加SiC_w作为填料可有效改善复合材料的热稳定性能,且当采用KH792型硅烷偶联剂时修饰率为6.37%。室温介电性能测试结果表明:添加改性SiC_w可提高复合材料的介电常数,相对纯PVDF提高了近8倍;在0.1wt%KH792-SiC_w/PVDF的介电性能测试中,当f=100 Hz时介电常数εr达到最大值33,介电损耗tanδ达到最小值0.07,且随频率的增加介电常数逐渐减小,介电损耗先减小后又增加;随着温度的增加,介电常数和介电损耗逐渐增加,当f=500 Hz,T=150℃时,εr最大为110,对应tanδ也最大为1.76。The basic requirement to prepare material which have good dielectric properties and mechanical properties is by using semiconducting nano whisker as filler and polymer as matrix.Firstly,different silane coupling agents were introduced onto SiC whisker(SiC w)surface by chemical modification,and then modified SiC w/polyvinylidene fluoride(PVDF)composite membrane was prepared by solution casting method.The modification effect of SiC w was analyzed by direct observation,FT-IR and thermogravimetric analysis.The distribution of SiC w in PVDF was observed by SEM,and the dielectric properties were compared under different temperatures.Silane coupling agent can be successfully introduced onto the surface of SiC w according to observation directly,FT-IR and thermogravimetric analysis results.The modified SiC w were distributed in the PVDF matrix uniformly by SEM and it illustrated the agglomeration of SiC w can be weakened obviously after introducing silane coupling agent into it.It was showed that the addition of SiC w can improve the thermal stability of PVDF effectively and the modification ratio is 6.37%if using KH792 as silane coupling agent.The dielectric properties of the composite membranes were measured at room temperature.It was found that the dielectric constant can be increased to eight times comparing with pure PVDF after addition of modified SiC w.The composite membrane showed better dielectric properties in 100-2000 kHz if 0.1wt%of KH792-SiC w was introduced to PVDF.The maximum ofεr was 33 and the minimum of tanδwas 1.76 at f=100 Hz.With the increase of frequency,the dielectric constant decreased while the dielectric loss decreased at first and then increased.The dielectric properties of 0.1wt%KH792-SiC w/PVDF membrane was also measured at 20-150℃.It was found that the maximum ofεr and tanδwas 110 and 0.07 at f=500 Hz under the temperature was 150℃,respectively.With the increase of temperature,the dielectric constant and dielectric loss increased gradually.

关 键 词：硅烷偶联剂 SIC晶须 PVDF 介电性能 复合薄膜 

分 类 号：TU332[建筑科学—结构工程]