Ultrasound-assisted-pressure-induced-flow leading to superior polymer/carbon nanotube composites and foams. (2nd December 2015)

• Record Type: Journal Article
• Authors: Li, Dachao; Fu, Dajiong; Yen, Ying-Chieh; Benatar, Avraham; Peng, Xiangfang; Chiu, Debbie Y.; Lee, L. James
• Is Part Of: Polymer. Volume 80(2015)
• Page Start: 237
• Page End: 244
• Publication Date: 2015-12-02
• Subjects: Polypropylene foams -- 'Brick and mud' structure -- Multi-wall carbon nanotube (MWCNT) -- Ultrasound -- Layer-by-layer bimodal structure; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2015.10.058
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: In the presented work, nano-sized carbon particles were coated onto the surface of semicrystalline polymer pellets and molded into an intermediate preform, with a honeycomb-like structure, at elevated temperatures and pressures. The preforms were further processed through pressure induced flow (PIF) at higher pressures or ultrasound assisted pressure induced flow (UAPIF) at lower pressures to achieve polymer nanocomposites with a co-continuous and 'brick and mud' structure. The particle-coated polymer pellets, preforms, and composites can be saturated or partially saturated with a blowing agent, so foaming may occur during or after molding to fabricate polymer nanocomposite foams with a layer-by-layer bimodal cell structure. Using polypropylene and carbon nanotubes as an example, and carbon dioxide as the blowing agent, we show that these new materials can provide superior mechanical and physical properties with good electrical conductivity and foam expansion ratio, not achievable by conventional nanocomposites and foams with the same composition. Graphical abstract: Highlights: High strength PP/MWCNTs nanocomposites were fabricated by using PIF processing and UAPIF processing. Ultrasound assisted PIF processing could substantially decrease the pressure required. Electrically conductive PP/MWCNTs nanocomposites with honeycomb-like structure was obtained. High expansion ratio PP nanocomposite foams with layer-by-layer structure and high mechanical strength were fabricated.