@Article{cmc.2010.017.215, AUTHOR = {J. Wang, D. C. C. Lam}, TITLE = {Nanostiffening in Polymeric Nanocomposites}, JOURNAL = {Computers, Materials \& Continua}, VOLUME = {17}, YEAR = {2010}, NUMBER = {3}, PAGES = {215--232}, URL = {http://www.techscience.com/cmc/v17n3/22561}, ISSN = {1546-2226}, ABSTRACT = {Selected elastic moduli of nanocomposites are higher than the elastic moduli of microcomposites. Molecular immobilization and crystallization at the interfaces had been proposed as potential causes, but studies suggested that these effects are minor and cannot be used to explain the magnitude observed in nanocomposites with >3nm particles. Alternately, molecular simulation of polymer deformation showed that rotation gradients can lead to additional molecular rotations and stiffen the matrix. The stiffening is characterized by the nanostiffening material parameter, l2. In this investigation, an analytical expression for nanostiffening in nanocomposites was developed using finite element analysis. The nanostiffening in nanocomposites was determined by the ratio of l2to the particle size r, and the expression was shown to be in good agreement with experimental data from the literature. The dependence on the ratio suggests that nanostiffening is significant only for nanocomposites with large l2/r but is negligible when l2/r is small.}, DOI = {10.3970/cmc.2010.017.215} }