抄録
In the previous researches and developments of polymer-impregnated concretes (abbreviated as PIC), relatively expensive methyl methacrylate monomer was used for impregnation and the concretes (base materials) impregnated with such monomer were covered by polyethylene film, aluminium foil, etc., during the polymerization process in order to prevent the evaporation of monomer. It is the object of this study to eliminate these disadvantages in the previous studies and prepare low-priced polymer-impregnated concretes reasonably.
In the experiments reported here, styrene monomer having about 1/3 of the cost of methyl methacrylate monomer was selected for impregnation and the basic conditions for manufacturing polystyrene-impregnated concretes were examined by using the heat-polymerization-in-hot-water method, which enables impregnated monomer to polymerize, but prevents the evaporation of monomer from the base material by hydrostatic pressure. In this case, the polystyrene-impregnated mortar or concrete was specially prepared by the heat-polymerization-in-hot-water method after impregnating a dried mortar or concrete with styrene monomer (with addition of trime-thyrolpropane trimethacrylate (TMPTMA) as a crosslinking agent and benzoyl peroxide as a catalyst), and the basic conditions of its process, that is, the composition of impregnating monomer, the temperature of hot water, the immersion time and the polymer-impregnating thickness (or polymer-penetrating depth), were examined.
The conclusions obtained from these experiments are summarized as follows :
(1) The composition of suitable impregnating monomer is : styrene 90, TMPTMA (crosslinking agent) 10, 50 % DOP solution of benzoyl peroxide (catalyst) 4-6 (by weight).
(2) The heat-polymerization-in-hot-water can be attained by immersing the mortar or concrete impregnated with the monomer in hot water at temperature of 70°C to 90°C for 2 hours or more.
(3) The polymer-impregnating thickness can be controlled by varying the evacuation time as well as the soaking time (in the monomer) of the base materials.
