Polymer/Graphene Composites via Spinodal Decomposition of Miscible Polymer Blends
Polymer/Graphene Composites via Spinodal Decomposition of Miscible Polymer Blends
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DOI：
10.1021/acs.macromol.9b01391
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发表时间：
2019-10-22
期刊：
影响因子：
5.5
通讯作者：
Macosko, Christopher W.
中科院分区：
文献类型：
--
作者：
Kou, Yangming;Cheng, Xiang;Macosko, Christopher W.
导电聚合物复合材料 (CPC) 具有广泛的工业应用，例如静电放电 (ESD) 保护。在此，我们首先将石墨烯纳米片（GNP）溶液混合到聚（甲基丙烯酸甲酯）（PMMA）和聚（苯乙烯-丙烯腈）（SAN）的可混溶混合物中，然后通过远高于较低临界溶液温度的退火诱导PMMA/SAN旋节线分解，从而构建了CPC。所得复合材料显示出空间规则、共连续的聚合物域，其中 GNP 优先位于富含 SAN 的相内并形成导电网络。我们发现 GNP 诱导 SAN 局部成核到厚度类似于 4R(g) 的表面层。在这些 SAN 层旁边形成了小的 PMMA 域，并且在较长的退火时间内保持稳定。结果，GNP 产生了局部混合形态，该形态不同于仅由旋节线分解产生的整体形态。在退火过程中，GNP 抑制了域粗化并保留了共连续形态，同时它们在聚合物基体中的连通性得到了改善。此外，诱导 PMMA/SAN 相分离使三元共混物的电导率显着提高了 5 个数量级以上。与将炭黑复合到均聚物基质中的传统 CPC 制造方法相比，我们的方法在 1 wt% GNP 负载量下实现了类似于 10(-8) S/cm 的整体电导率，使该系统适合 ESD 保护。
Conductive polymer composites (CPCs) enjoy broad industrial applications such as electrostatic discharge (ESD) protection. Herein, we constructed CPCs by first solution blending graphene nanoplatelets (GNPs) into a miscible blend of poly(methyl methacrylate) (PMMA) and poly(styrene-co-acrylonitrile) (SAN) and then inducing PMMA/SAN spinodal decomposition by annealing well above the lower critical solution temperature. The resulting composite showed spatially regular, co-continuous polymer domains, in which GNPs preferentially localized within the SAN-rich phase and formed a conductive network. We found that GNPs induced local nucleation of SAN into surface layers of similar to 4R(g) in thickness. Small PMMA domains formed next to these SAN layers and were stable against long annealing times. As a result, GNPs created local blend morphologies that were different from the bulk morphology arising from spinodal decomposition alone. During annealing, GNPs suppressed domain coarsening and preserved the co-continuous morphology, while their connectivity in the polymer matrix was improved. Additionally, inducing PMMA/SAN phase separation significantly increased the ternary blend's electrical conductivity by over 5 orders of magnitude. Compared to the conventional approach of CPC manufacture of compounding carbon black into a homopolymer matrix, our approach achieved bulk electrical conductivity of similar to 10(-8) S/cm at 1 wt % GNP loading, rendering this system suitable for ESD protection.