| The specific problem that is of concern here is to stop or at least significantly retard the diffusion of hazardous substances which are released into public places. The solution proposed is to employ the rapidly gelling hydrogels that display effective barrier property to cover the hazardous substances. Rapidly gelling hydrogels are a class of hydrogel materials that can solidify from liquid states at application sites within a short time. Different strategies have been utilized to obtain rapidly gelling hydrogels, due to their potential use in biomedical applications and daily-care applications. In this work, we firstly applied the rapidly gelling hydrogels to the coverings for hazardous substances, and studied the barrier property of the rapidly gelling hydrogels to hazardous substances. In the present studies, the compositions of the PVA/borax hydrogels were optimized according to the characterizing of the gelation time and the stretchability, and rapidly-gelling PVA/toughener/borax hydrogels and PVA/toughener/disinfectant/borax hydrogels based on the optimal composition were obtained. Additionally, the barrier property of the hydrogels to hazardous substances under different conditions was investigated.1. The effects of the reactant composition on the gelation time and the stretchability of hydrogels were investigated in order to obtain the optimal composition of PVA/borax hydrogels. Toughener was incorporated so as to improve the stretchability of the PVA/borax crosslinked system, and the PVA/toughener/borax hydrogels were prepared within a short time. The disinfectants of sodium carbonate and sodium dichloroisocyanurate were incorporated in order to reduce the penetration rates of hazardous substances, and the PVA/toughener/disinfectant/borax hydrogels were prepared..2. The rapidly gelling hydrogels could be a promising barrier material to hazardous chemicals and bacteria. The composition of the hydrogels is 15wt% PVA,0.6wt% SA,0%～0.74% disinfectant and 1:25 borax:PVA ratios. More than 99.9% of the dichlorodiethyl sulfide, dichlorvos, sarin and sodium cyanide can be confined for 12 h by using 10 mm thick hydrogels when the concentration of hazardous chemicals was 20 g/m2～100 g/m2. When the thickness of the hydrogels was 5 mm,100% of the bacillus subtilis, colibacillus and staphylococcus aureus can be confined for one day. The hydrogels exhibited self-healing capability and favorable temperature independence, which demonstrates its superiority as a covering material. |
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