Flexible and stretchable polyurethane/waterglass grouting material

Flexibility and stretchability are of ever increasing importance in constructing high-performance grouting materials. Herein, a facile, effective and cost-efficient strategy to make organic-inorganic hybrid chemical grouting material in a “flexible and stretchable” way was based on polymerization of carbon double bond and excellent synergistic interactions among N-Methylol acrylamide, butenediol, waterglass and prepolymer. Upon the optimal percentages of waterglass (44%), N-Methylol acrylamide (3.5%), butenediol (1.5%), Alkylphenol polyoxyethylene (OP-9, 0.5%), 2,2′-azobis[2-(2-imidazolin-2-yl)propane] (0.35%), 2,2-dimorpholinodiethylether (DMDEE, 0.15%) and prepolymer (50%), the obtained polyurethane/waterglass grouting material with three-dimensional interpenetrating network structure displayed an excellent flexibility, satisfactory compressive strength of 13.4 MPa at 50% compression state, and relatively large elongation of up to 60% with a stable stretching for 200 times. The grouting material was mainly composed of amorphous polyurethane and crystalline polysilicic acid/NaHCO3/Na2CO3 composite, and its probable formation mechanism was proposed. Additionally, the grouting material possessed favorable thermal stability and repairment performance for roadway cracks. This work may open a simple and convenient avenue for the preparation of organic-inorganic hybrid chemical grouting material with flexibility and stretchability.