Kar Goutam Prasanna, Biswas Sourav, Bose Suryasarathi
Department of Materials Engineering, Indian Institute of Science, Bangalore-560012.
Phys Chem Chem Phys. 2015 Jun 14;17(22):14856-65. doi: 10.1039/c5cp01452b.
A unique approach was adopted to drive the multiwall carbon nanotubes (MWNTs) to the interface of immiscible PVDF-ABS blends by wrapping the nanotubes with a mutually miscible homopolymer (PMMA). A tailor made interface with an improved stress transfer was achieved in the blends with PMMA wrapped MWNTs. This manifested in an impressive 108% increment in the tensile strength and 48% increment in the Young's modulus with 3 wt% PMMA wrapped MWNTs in striking contrast to the neat blends. As the PMMA wrapped MWNTs localized at the interface of PVDF-ABS blends, the electrical conductivity could be tuned with respect to only MWNTs, which were selectively localized in the PVDF phase, driven by thermodynamics. The electromagnetic shielding properties were assessed using a vector network analyser in a broad range of frequency, X-band (8-12 GHz) and Ku-band (12-18 GHz). Interestingly, enhanced EM shielding was achieved by this unique approach. The blends with only MWNTs shielded the EM waves mostly by reflection however, the blends with PMMA wrapped MWNTs (3 wt%) shielded mostly by absorption (62%). This study opens new avenues in designing materials, which show simultaneous improvement in mechanical, electrical conductivity and EM shielding properties.
采用了一种独特的方法，通过用互溶的均聚物（聚甲基丙烯酸甲酯，PMMA）包裹多壁碳纳米管（MWNTs），将其驱动至不混溶的聚偏氟乙烯-丙烯腈-丁二烯-苯乙烯共聚物（PVDF-ABS）共混物的界面。在含有PMMA包裹的MWNTs的共混物中实现了具有改善的应力传递的定制界面。这表现为，与纯共混物形成鲜明对比的是，含有3 wt% PMMA包裹的MWNTs的共混物的拉伸强度显著提高了108%，杨氏模量提高了48%。由于PMMA包裹的MWNTs定位于PVDF-ABS共混物的界面，电导率仅可根据MWNTs进行调节，MWNTs由热力学驱动选择性地定位于PVDF相中。使用矢量网络分析仪在宽频率范围，即X波段（8-12 GHz）和Ku波段（12-18 GHz）评估电磁屏蔽性能。有趣的是，通过这种独特的方法实现了增强的电磁屏蔽。仅含有MWNTs的共混物主要通过反射来屏蔽电磁波，然而，含有PMMA包裹的MWNTs（3 wt%）的共混物主要通过吸收来屏蔽（62%）。这项研究为设计材料开辟了新途径，这些材料在机械性能、电导率和电磁屏蔽性能方面同时得到改善。
