Preparation and Performance Enhancements of Low-Heat-Releasing Polyurethane Grouting Materials with Epoxy Resin and Water Glass

Abstract

Polyurethane (PU) grouting materials possess excellent fluidity and strong injectability. However, the high heat release during the reaction process restricts its application. In this study, with the addition of water glass (WG), a prepolymer was prepared by epoxy resin reacted with isocyanate to form modified polyurethane. The effects of epoxy resin and water glass on the compressive properties, expansion rate, structure of the cell, and maximum reaction temperature of the grouting materials were also investigated. The results showed that the cell size of modified PU was smaller and more regular, the maximum reaction temperature of the modified PU was reduced to 89 °C, and the compressive strength and expansion rate went up to 0.27 MPa and 57, respectively. This investigation will expand the application of PU grouting materials in underground engineering.

Novel polyurethane foam with low released heat for application in bone binder

“…The polymer cross-linking density was determined by swelling equilibrium experiment. 22 The mechanical properties and bond strength of the samples were tested by universal mechanical property tester (WDW-20, Wanchen).…”

“…For example, physical foaming agent (HCFC-141b) and high-boiling point solvent were used to reduce the released heat of PU. The released heat-induced temperature was still high as about 101.0 C. 21 The water glass was introduced to curing system of PU to reduce the released heat of PU, in which released heat-induced temperature was reduced from 124.6 to 89 C. 22 The water glass and thermally conductive aluminum oxide (Al 2 O 3 ) were added to PU, in which the released heat-induced temperature was reduced from 115.0 to 95 C. From above respects, although the released heat-induced temperature of conventional PU have been reduced by tuning its reaction process or improving its thermal conductivity, yet, it still exhibits high temperature (>80 C). So, it is still a high interesting to find a new method for reducing released heat of PU-based bone adhesive.…”

“…The released heat‐induced temperature was still high as about 101.0°C 21 . The water glass was introduced to curing system of PU to reduce the released heat of PU, in which released heat‐induced temperature was reduced from 124.6 to 89°C 22 . The water glass and thermally conductive aluminum oxide (Al 2 O 3 ) were added to PU, in which the released heat‐induced temperature was reduced from 115.0 to 95°C.…”

Effect of a Simulated Coal Mine Environment on Polyurethane Grouting Material and a Proposed Polyurethane Strengthening Method

“…Grouting technology, which plays a significant role in the field of green mine construction, has been widely utilized in mine engineering as an effective means to seal water, stabilize ground, heat insulation, and repair cracks [1]. Over the past few decades, distinct grouting materials have been developed, such as waterglass [2], silica sol [3], cement [4], PU, epoxy resins [5], and their compounds [6]. Given its excellent synthetic properties, such as its outstanding chemical stability [7], large expansion rate [8], high mechanical strength [9], corrosion resistance [10], self-extinguishing flame retardancy [11], low environmental pollution risk, low permeability [12], and fast reaction times, PU grouting has been widely applied as a sealing and plugging method to prevent mine disasters [13].…”