Effects of interfacial interaction on chain dynamics of rubber/graphene oxide hybrids: a dielectric relaxation spectroscopy study
Effects of interfacial interaction on chain dynamics of rubber/graphene oxide hybrids: a dielectric relaxation spectroscopy study
复制标题
DOI：
10.1039/c3ra41998c
复制
发表时间：
2013-08
期刊：
影响因子：
3.9
通讯作者：
Siwu Wu;Zhenghai Tang;B. Guo;Liqun Zhang;D. Jia
中科院分区：
文献类型：
--
作者：
Siwu Wu;Zhenghai Tang;B. Guo;Liqun Zhang;D. Jia
采用不同絮凝剂氯化氢和氯化钙共混法制备了氧化石墨烯（GO）片与丁二烯-苯乙烯-乙烯基吡啶橡胶（VPR）的杂化体，形成离子键（HVPR）和氢键（CaVPR）界面。为了揭示界面相互作用对链动力学的影响，研究了这些杂化体的介电弛豫谱。结果表明，所有杂化体均表现出两种不同的弛豫过程：节段弛豫和界面弛豫。氧化石墨烯的浓度对CaVPR的节段动力学没有影响，但在氧化石墨烯浓度为1.5 vol%时，HVPR的节段动力学减慢。同时，HVPR的节段弛豫总是略快于CaVPR。在5 ~ 35℃的温度范围内，氧化石墨烯掺入量低于2.5 vol%的杂化材料均出现了一种新的弛豫模式，其弛豫模式比节段弛豫模式慢，这是由限制链动力学的间相引起的。HVPR界面弛豫时间随氧化石墨烯浓度的降低而减小。而在CaVPR中，随着氧化石墨烯浓度的降低，它先降低后升高。最有趣的是，HVPR的界面弛豫比CaVPR慢。在相同氧化石墨烯浓度下，HVPR中界面链的介电强度（Δe）、计算脆性参数和有效活化焓均高于CaVPR。所有证据表明，HVPR的界面相互作用强于CaVPR。
Hybrids consisting of graphene oxide (GO) sheets and butadiene-styrene-vinyl pyridine rubber (VPR) were prepared by a co-coagulation process with different flocculants, hydrogen chloride and calcium chloride, in order to form two kinds of bonding interfaces, namely ionic bonding (HVPR) and hydrogen bonding (CaVPR) interfaces. To reveal the effects of interfacial interaction on the chain dynamics, the dielectric relaxation spectra of these hybrids have been investigated. The results show that all hybrids exhibit two distinct relaxation processes, segmental relaxation and interfacial relaxation. The concentration of GO has no impact on the segmental dynamics of CaVPR, but the segmental dynamics of HVPR slow down at 1.5 vol% of GO. Meanwhile, the segmental relaxation of HVPR is always a little faster than its CaVPR counterpart. In the temperature range of 5–35 °C, a new relaxation mode, which is slower than the segmental relaxation and attributed to the interphase with restricted chain dynamics, has been observed for all the hybrids with a GO loading lower than 2.5 vol%. The interfacial relaxation time of HVPR decreases with decreasing GO concentration. However, in CaVPR it first decreases and then increases with decreasing GO concentration. Most interestingly, the interfacial relaxation of HVPR is slower than that for CaVPR. The dielectric strength (Δe), the calculated fragility parameter and the effective activation enthalpy of the interfacial chains in HVPR are always higher than those in CaVPR with the same GO concentration. All the evidence indicates the stronger interfacial interactions in HVPR than in CaVPR.