Journal of Colloid and Interface Science, Vol.291, No.2, 388-395, 2005
Polymerization contraction of light-cured composite resins containing silica/polymethylmethacrylate bonded microstructured networks
The adsorption of methylmethacrylate polymer at silica/methyl methacrylate interfaces was determined to provide microstructured networks whose structural characteristics were determined to be controlled by the amount of polymer initially supplied to the system. First, the microstructure was investigated by determining as a function of the amount of polymer (i) the shrinking rate due to evaporation of the methylmethacrylate monomer, (ii) the rate of sedimentation of the silica/polymer complexes in the methylmethacrylate monomer, and (iii) the height of the sediment in the long term. These different characteristics were found to be strongly correlated. Second, the sedimentation characteristics were determined as a function of the amount of polymer initially supplied to the dispersion of the same silica/polymer system in the ethylene glycol dimethacrylate monomer. Then the rate of the polymerization contraction during light-curing of the resin was determined for the sediment recovered after centrifugation. The slowest polymerization contraction and the smallest contraction were obtained with the filler/polymer/resin system composed of aggregates of medium porosity and size. (c) 2005 Elsevier Inc. All rights reserved.
Keywords:aggregation of silica particles;polymerization contraction;silica/polymer complexes in organic media