Resistance to time-dependent deformation of nanoparticle/polymer composites

Dimensional stability and structural reliability are major concerns for thermoplastics due to their nature of high mobility of polymer chains. Here the authors report the creep experiments on polypropylene filled with 1 vol % TiO2 nanoparticles with diameter of 21 or 300 nm at different load levels and temperatures, which show that the dimensional stability of the nanocomposites is significantly improved, especially by loading small sized nanoparticles. The creep strain and creep rate of nanoparticle-filled polypropylene are reduced by 46% and 80%, respectively, compared to those of the neat matrix. Additionally, creep lifetime is extended by 330% due to the addition of small nanoparticles. (c) 2007 American Institute of Physics.