合成了2-羟基萘醛苯乙酰腙(1)、2-羟基萘醛-4-羟基苯乙酰腙(2)和2-羟基萘醛-2-甲氧基苯乙酰腙(3)三种新型酰腙化合物,通过单晶X射线衍射(XRD)、元素分析和傅里叶变换红外(FTIR)光谱对化合物结构进行了表征。单晶X射线衍射结果表明,化合物2和3结晶为单斜晶系,空间群C2/c。而化合物1结晶为正交晶系,空间群为Pbca。热重(TG)分析结果表明,化合物1、2、3分子骨架热分解的温度分别为318.23、319.04、323.01°C,对应的热分解过程表观活化能分别为115.90、145.18、129.38 k J?mol-1。微量热研究表明,三种酰腙及其前驱体酰肼与小牛胸腺脱氧核糖核酸(CT-DNA)相互作用均为吸热作用,但作用时间(1.00-50.0 min)和反应熵变(0.47-15.50 k J?mol-1)有较大的差异。化合物1和2与CT-DNA的反应焓变均大于其前驱体酰肼a和b与CT-DNA的反应焓变,而化合物3与CT-DNA的反应焓变却小于其前驱体酰肼c与CT-DNA的反应焓变。
In this work, graphene oxide(GO) nanosheets with surface modification by Tannic and Fe coordination complexes(TA-Fe) were incorporated into poly(vinylidene fluoride)(PVDF) to prepare high constant but low loss polymer nanocomposites, and the effect of TA-Fe interlayer on dielectric properties of the GO@TA-Fe/PVDF nanocomposites was investigated. The results indicate that the dosage, mixing ratio, and reaction time of TA-Fe complexes have obvious influences on the dielectric properties of the nanocomposites. Furthermore, the TA-Fe interlayer significantly influences the electrical properties of GO@TA-Fe nanoparticles and their PVDF composites, and the GO@TA-Fe/PVDF composites exhibit superior dielectric properties compared with raw GO/PVDF. Dielectric losses of the GO@TA-Fe/PVDF are significantly suppressed to a rather low level owing to the presence of TA-Fe layer, which serves as an interlayer between the GO sheets, thus preventing them from direct contacting with each other. Additionally, the dynamic dielectric relaxation of the GO/PVDF and GO@TA-Fe/PVDF nanocomposites was investigated in terms of temperature.
