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Journal of Nanomaterials
Volume 2015, Article ID 136204, 11 pages
http://dx.doi.org/10.1155/2015/136204
Research Article

Influence of Thermal Treatment on Mechanical and Morphological Characteristics of Polyamide 11/Cellulose Nanofiber Nanocomposites

1Polymer Department, National Institute for Research and Development in Chemistry and Petrochemistry, 202 Splaiul Independentei, 060021 Bucharest, Romania
2Faculty of Applied Chemistry and Material Science, University Politehnica of Bucharest, 1-7 Gh. Polizu Street, 011061 Bucharest, Romania

Received 19 November 2014; Accepted 23 January 2015

Academic Editor: Yibing Cai

Copyright © 2015 Denis Mihaela Panaitescu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Nanocomposite films were prepared from polyamide 11 (PA11) and cellulose nanofibers (CN) by melt compounding and compression molding. The impact of thermal treatment on the morphology and mechanical behavior of PA11 and nanocomposite films was studied using dynamic mechanical analysis, tensile tests, X-ray diffraction (XRD), and peak force (PF) QNM technique. Slightly higher storage modulus values were obtained for nanocomposites compared to the matrix before the treatment, but a noticeable increase was observed after the treatment. Although CN addition determined increased tensile strength and modulus both before and after the treatment, the increase was much more significant in the case of treated films. The best mechanical properties were shown by treated PA11 films containing 5 wt% CN, with 40% higher Young’s modulus and with 35% higher tensile strength compared to the matrix. Some of the changes pointed out by static and dynamic mechanical tests were explained by the morphological changes determined by the thermal treatment and emphasized by PF QNM and by the increase of XRD crystallinity. A transition from lamellar stack morphology to one involving spherulites was highlighted by AFM. Thermal treatment has proved a valuable method for improving the mechanical properties of PA11/CN composites.