Bershtein Vladimir, Fainleib Alexander, Egorova Larisa, Gusakova Kristina, Grigoryeva Olga, Kirilenko Demid, Konnikov Semen, Ryzhov Valery, Yakushev Pavel, Lavrenyuk Natalia
Ioffe Physical-Technical Institute, RAS, 194021, St Petersburg, Russia.
Institute of Macromolecular Chemistry, NAS, 02160, Kyiv, Ukraine.
Nanoscale Res Lett. 2015 Apr 8;10:165. doi: 10.1186/s11671-015-0868-5. eCollection 2015.
Thermostable nanocomposites based on densely cross-linked cyanate ester resins (CER), derived from bisphenol E and doped by 0.01 to 5 wt. % amino-functionalized 2D montmorillonite (MMT) nanoparticles, were synthesized and characterized using Fourier transform infrared (FTIR), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDXS), wide-angle X-ray diffraction (WAXD), dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), far-infrared (Far-IR), and creep rate spectroscopy (CRS) techniques. It was revealed that ultra-low additives, e.g., 0.025 to 0.1 wt. %, of amino-MMT nanolayers covalently embedded into СER network exerted an anomalously large impact on its dynamics and properties resulting, in particular, in some suppression of dynamics, increasing the onset of glass transition temperature by 30° to 40° and twofold rise of modulus in temperature range from 20°C to 200°C. Contrarily, the effects became negligibly small or even negative at increased amino-MMT contents, especially at 2 and 5 wt. %. That could be explained by TEM/EDXS data displaying predominance of individual amino-MMT nanolayers and their thin (2 to 3 nanolayers) stacks over more thick tactoids (5 to 10 nanolayers) and the large amino-MMT aggregates (100 to 500 nm in thickness) reversing the composite structure produced with increasing of amino-MMT content within CER matrix. The revealed effect of ultra-low amino-MMT content testifies in favor of the idea about the extraordinarily enhanced long-range action of the 'constrained dynamics' effect in the case of densely cross-linked polymer networks.
82.35.Np Nanoparticles in polymers; 81.05.Qk Reinforced polymers and polymer-based composites; 81.07.Pr Organic-inorganic hybrid nanostructures.
基于双酚E的致密交联氰酸酯树脂（CER），并掺杂0.01至5 wt.%氨基功能化二维蒙脱土（MMT）纳米粒子的热稳定纳米复合材料，采用傅里叶变换红外光谱（FTIR）、透射电子显微镜（TEM）、能量色散X射线光谱（EDXS）、广角X射线衍射（WAXD）、动态力学分析（DMA）、差示扫描量热法（DSC）、热重分析（TGA）、远红外（Far-IR）和蠕变速率光谱（CRS）技术进行了合成与表征。结果表明，共价嵌入CER网络中的超低含量添加剂，如0.025至0.1 wt.%的氨基MMT纳米层，对其动力学和性能产生了异常大的影响，特别是导致了动力学的一些抑制，使玻璃化转变温度的起始温度提高了30°至40°，并使20°C至200°C温度范围内的模量提高了两倍。相反，当氨基MMT含量增加时，尤其是在2 wt.%和5 wt.%时，这些影响变得微不足道甚至为负。这可以通过TEM/EDXS数据来解释，该数据显示单个氨基MMT纳米层及其薄（2至3纳米层）堆叠比更厚的片层（5至10纳米层）和大的氨基MMT聚集体（厚度为100至500纳米）占优势，随着CER基质中氨基MMT含量的增加，复合结构发生了逆转。超低氨基MMT含量所揭示的效应证明了在致密交联聚合物网络的情况下，“受限动力学”效应的远程作用得到了异常增强这一观点。
82.35.Np 聚合物中的纳米粒子；81.05.Qk 增强聚合物和聚合物基复合材料；81.07.Pr 有机-无机杂化纳米结构。
