Polysilazane as a new foaming agent to prepare high-strength, low-density epoxy foam

Abstract

Polysilazane (PSN2) was used as chemical foaming agent to prepare epoxy foam for the first time. Using the new foaming agent, epoxy foams with high strength and low density were successfully prepared. The density of epoxy foam can be tuned from 0.321 to 0.151 g cm −3 by changing the content of PSN2 from 2.50 to 7.50 wt%, with the compressive strength varied from 7.39 to 1.25 MPa. The morphology, porosity, mechanical property, thermal conductivity and adhesive property of foams with different polysilazane content were investigated. Besides, the effect of polyamine curing agent and surfactant on foams was also investigated to optimize the as-prepared epoxy foam.

Preparation of epoxy resin foam by composite foaming agent prepared from microporous silica and 4,4′‐bisoxybenzenesulfonyl hydrazide

“…It is difficult for the epoxy resin foam obtained by traditional chemical foaming methods to reach the megapascal level, often only a few MPa. [45][46][47] It is obvious from the compression curve that traditional foaming is far lower than the compression strength obtained by our method. Therefore, our mechanical level is improved by one to two orders of magnitude.…”

“…Compared with epoxy resin foam (8% CFA), epoxy resin foam (7% CFA) has a higher compressive strength (34 MPa). It is difficult for the epoxy resin foam obtained by traditional chemical foaming methods to reach the megapascal level, often only a few MPa 45‐47 . It is obvious from the compression curve that traditional foaming is far lower than the compression strength obtained by our method.…”

Self-foaming polymers: Opportunities for the next generation of personal protective equipment

“…[246] Cheng et al expanded epoxy formulations with a polysilazane (PSN) compound instead of PMH. [247] The difference with PMH is the nature of the released gazes. In the case of PSN, gaseous dihydrogen is released first, followed by the formation of ammonia as schematized in Figure 24a.…”

Ultra-porous and lightweight microwave absorber based on epoxy foam loaded with long carbon fibers

“…However, the epoxy foams show a higher density than that of PU foam composites [12][13][14] which further limits their use in anechoic chambers, where voluminous absorbers are used to provide absorption at low frequencies (typically < 2 GHz). Several studies have focused on reducing the density of epoxy foam [15] and epoxy resin [12,16] based composites. Indeed, several foaming methods of composite materials are studied [17] and porous composites can be prepared from resins using mechanical [18-20], physical [21] and chemical blowing agents [22,23] or by processing techniques like foaming by injection or extrusion molding [24,25].…”