Formation of stretched fibrils and nanohybrid shish-kebabs in isotactic polypropylene-based nanocomposites by application of a dynamic oscillatory shear
| Autor: | Wei Li, Lengwan Li, Tairong Kuang, Xiangfang Peng, Kunlun Hong, Hao-Yang Mi, Lihong Geng, Bin-Yi Chen |
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| Rok vydání: | 2018 |
| Předmět: |
chemistry.chemical_classification
Materials science Nanocomposite Polytetrafluoroethylene General Chemical Engineering 02 engineering and technology General Chemistry Polymer Molding (process) 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Industrial and Manufacturing Engineering 0104 chemical sciences chemistry.chemical_compound chemistry Flexural strength Tacticity Environmental Chemistry Composite material 0210 nano-technology Superstructure (condensed matter) Nanoscopic scale |
| Zdroj: | Chemical Engineering Journal. 348:546-556 |
| ISSN: | 1385-8947 |
| DOI: | 10.1016/j.cej.2018.04.197 |
| Popis: | The hierarchical structures from micro- to nano-scale in polymeric materials can dramatically affect their physical properties. Controlling the formation of hierarchical structures in polymers through processing remains a challenge. We present here a green and convenient polymer processing approach to prepare isotactic polypropylene (iPP)/polytetrafluoroethylene (PTFE) nanocomposites with hierarchical superstructures via recently developed loop oscillating push-pull molding (LOPPM) method. By taking full advantage of intense oscillatory shear, the in situ generated PTFE fibrils are refined into nanoscale and well aligned, serving as the central shish to induce the formation of nanohybrid shish-kebab (NHSK) superstructure with iPP crystalline lamellae (kebabs). The structure evolution of NHSK superstructures was further examined using molecular dynamics simulations. The stretched fibrils can promote the kebabs growing into large domains with a more compact and ordered molecular chain configuration, compared to that in systems without fibrils or with flexible fibrils. The well-aligned fibrils and NHSK superstructure play a crucial role in enhancing properties. The prepared iPP/PTFE nanocomposites containing 3 wt% PTFE achieved 197.9% and 36.0% improvement in impact and flexural strength, respectively, as compared with the conventional injection-molded composites. Meanwhile, the LOPPM iPP/PTFE nanocomposites exhibits excellent resistance to thermal deformation under harsh environment (over 150 °C) while fabricates a hydrophobic surface. These findings provide a facile strategy to produce high-performance polymers from judiciously controlled sample preparations. |
| Databáze: | OpenAIRE |
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