Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Aggregate of nanoparticles: rheological and mechanical properties | Wang et al. Nanoscale Research Letters 2011 6 114 http content 6 1 114 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Aggregate of nanoparticles rheological and mechanical properties Yu Wang Xiaojun Wu Wei Yang Yuanming Zhai Banghu Xie Mingbo Yang Abstract The understanding of the rheological and mechanical properties of nanoparticle aggregates is important for the application of nanofillers in nanocompoistes. In this work we report a rheological study on the rheological and mechanical properties of nano-silica agglomerates in the form of gel network mainly constructed by hydrogen bonds. The elastic model for rubber is modified to analyze the elastic behavior of the agglomerates. By this modified elastic model the size of the network mesh can be estimated by the elastic modulus of the network which can be easily obtained by rheology. The stress to destroy the aggregates . the yield stress sy and the elastic modulus G of the network are found to be depended on the concentration of nano-silica j wt. with the power of and respectively. Via this concentration dependent behavior we can extrapolate two important mechanical parameters for the agglomerates in a dense packing state j 1 the shear modulus and the yield stress. Under large deformation continuous shear flow the network structure of the aggregates will experience destruction and reconstruction which gives rise to fluctuations in the viscosity and a shear-thinning behavior. Introduction An important application of nano-fillers is to construct nanocomposites with high performance of mechanical properties or certain functionality 1 . Usually for their high surface energy nano-fillers exist in the form of agglomerates. Interestingly some agglomerates such as nano-silica and nano-titanium dioxide can present a chain-like form what is called nanoparticle chain aggregates NCA and its dynamic properties have been mainly revealed by the work of .
