Correlation Between Nanostructure and Crystalline Morphology and Mechanical Response in Nylon 6 Nanocomposites
- PDF / 452,398 Bytes
- 9 Pages / 612 x 792 pts (letter) Page_size
- 110 Downloads / 241 Views
B5.10.1
Correlation Between Nanostructure and Crystalline Morphology and Mechanical Response in Nylon 6 Nanocomposites E. Reynaud, D. Shah and E.P. Giannelis Department of Materials Science and Engineering, Cornell University, Ithaca, N.Y. 14853, U.S.A. ABSTRACT Several nylon nanocomposites was prepared using pristine and organically modified silicates. DSC and XRD reveal that the metastable γ phase is stabilized in the nanocomposites and the amount of γ phase scales with the silicate loading. Both storage and loss moduli of the nanocomposites increase with increasing silicate content. The overall characteristics of these systems become more solid-like before the onset of the glass transition. The increases in moduli are most pronounced in the rubbery regime. Pristine silicates have marginal effect on the mechanical response due to poor dispersion and/or lack of interactions with the polymer matrix. INTRODUCTION Polymer-silicate nanocomposites have received widespread attention in the past decade due to impressive property enhancements. The presence of silicate layers in the polymer matrix has a profound influence in the mechanical response of the nanocomposite. This change is a function of the physical dimensions of the silicate layer, dispersion, as well as the interfacial interaction between the silicate surface and the surrounding polymer. Our current research focuses on understanding these effects with the eventual aim of being able to fine-tune modulus and damping of these nanocomposite materials. Polymer silicate nanocomposites have crossed the threshold between research and application [1-3]. Nylon and Thermoplastic Olefin nanocomposites have entered the production stage. There is also better understanding at this point about some of the driving forces behind silicate dispersion in the polymer matrix [4,5]. However the debate remains on how the nanostructure affects the final properties of the resulting nanocomposite. Observed property enhancements for all polymer-silicate combinations do not follow similar trends even for systems with comparable levels of dispersion. Additional complications arise when semi-crystalline systems are investigated. The presence of polymorphic crystalline forms and the effect of the organic-inorganic interface on the crystallization behavior raises a lot of interesting questions regarding the role of the nanoparticles in determining the nanostructure of the polymer crystallites and the properties of the nanocomposite. Nylon 6 nanocomposites are of particular interest because they represent one of the earliest breakthroughs in nanocomposite research and also because they exhibit an across the board improvement of various mechanical and barrier properties with seemingly few tradeoffs in the process. It has been shown that both the α and γ phases are present in the nylon 6 – silicate nanocomposite [6]. Recent work by Vaia et al. has
B5.10.2
shed further light on these hybrids [7,8]. It has been reported that of the α and γ phases, the γ phase is preferentially formed in these s
Data Loading...
