Effect of nanoparticles orientation on morphology of polymeric nanocomposite foams: preparation of foamed nanocomposite fibers by supercritical carbon dioxide

ABSTRACT

Polymeric foams have received increasing attention in both academic and industrial communities. Using of nanoparticles as heterogeneous nucleation agent has been verified as one of the most valid means to enhance cell nucleation and improve cell morphology. However, few researches have been conducted to investigate the effect of the nanoparticles’ spatial orientation on their nucleation efficiency. In this work, to study the influence of the orientation of nanoparticles on their performance in improving morphology of polymeric foam, thermoplastic polyurethane (TPU) composite fibers with different nanoparticles (carbon nanotubes, graphene and SiO₂) were prepared by using different traction speeds. The different traction speeds lead to different orientation state of the nanoparticles which then resulted different nucleation effect. It was found that carbon nanotubes (CNTs) were easily oriented and aligned along the fiber length direction under the high traction speed, while graphene and SiO₂ nanoparticles did not show orientation under the traction speed in this study. As a result, the foam of TPU/CNTs composite fibers from high traction speed exhibited a much smaller cell size and higher cell density compared to the foams of the fibers from low traction speeds, while TPU/graphene, and TPU/SiO₂ composite fibers with different traction speeds showed almost similar cell size and size density after foaming, indicating that the orientated nanoparticles possessed higher heterogeneous nucleation efficiency. To our best knowledge, this work, for the first time, demonstrated the high nucleation effect of the aligned nanoparticles, which hopefully open a new path for improving the cell morphology of polymeric foam materials.

Graphical ABSTRACT

KEYWORDS:

• Nanoparticles
• TPU
• carbon nanotubes
• foaming

Additional information

Notes on contributors

Guojun Hu

Guojun Hu is an associated professor in Information, mechanical and electrical Engineering Branch College, Shaoxing University Yuanpei College. He received his B.E. in Mechanical Engineering at Northwestern Polytechnical University (1989). His current research focuses on mechanical manufacturing and automation and polymer processing machine.

Fang Feng

Fang Feng is an associated professor in Information, mechanical and electrical Engineering Branch College, Shaoxing University Yuanpei College. Feng earned his B.S. and M.E in Mechanical Engineering at Zhejiang University of Technology (1998) and Taiyuan University of Technology (2007), respectively. The Feng’s current research mainly focuses on the application CAD/CAM in mechanical engineering and polymer processing. He has published more than 10 peer reviewed papers, edited two textbooks, and presided several projects at provincial and ministerial level.