Zeolite filled siloxane composite foams: Compression property

Abstract

In this article, mechanical behavior under compression loads of an innovative adsorbent material, based on silicone composite foams filled with SAPO 34 zeolite, is presented. The innovative composite foams were obtained profiting by the dehydrogenative coupling of siloxane constituents. These new adsorbent systems have been proposed to overcome to the low mechanical stability of conventional SAPO-34 coating for adsorption chiller. In this concern, static and cyclic compressive tests at room temperature have been carried out. Samples at increasing content of SAPO 34 zeolite were tested to evaluate the influence of the filler content on the mechanical behavior of the composite foam. The results showed that the presence of zeolite reduces the elastic limit of the foam and increases the strength. The foams evidenced also acceptable mechanical stability to cyclic compressive loads. The encouraging results confirm the possible use of these new composite foams as adsorbent materials for cyclic adsorption heat pumps. V C 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46145.

Experimental evaluation of the hydrothermal stability of a silicone/zeolite composite foam for solar adsorption heating and cooling application

“…Consequently, the mechanical compression behavior will be characterized by a very flat plateau region . Vice versa, if the foam has a certain structural inhomogeneity or low foaming ratio, the collapse regime will be characterized by a stress plateau having a certain slope Finally, the densification stage, in which an abrupt stress increase occurs, can be identified.…”

“…39 At the same time, due to the presence of a large number of hydroxyl groups on the surface of the zeolite, there will be an increase in crosslinking combined with a reduction of the foaming ratio which will make the structure more rigid. 35 The composite foam can be schemed consisting of multiple micelles, consisting of a zeolite particle core and an external siloxane shell, chemically interconnected each other (as high crosslinking level of the foam). 38,40 Figure 5 shows cross-sectional view of cell wall in a F50 composite foam.…”

“…This structural nonuniformity is a direct consequence of the greater difficulty of foaming found for this type of samples, which leads to a structure, mechanically stable but characterized by local heterogeneity. 35,41 The higher content of zeolite makes the slurry more viscous and therefore makes the chemical and physical foaming process, that usually takes place for this class of composite foams, 25 less effective. This lack of structural homogeneity has repercussions on the mechanical behavior of the foam in the medium and long aging time.…”

Assessment of sorption kinetics of carbon nanotube‐based composite foams for oil recovery application

“…Finally, the tin catalyst (0.5 g) was added under vigorous stirring for about 15 s. The final mixture was put in a cylindrical mold with diameter 2 cm defining a proper shape during the foaming phase. The foaming is caused by the chemical reaction between PDMS and PMHS compounds that involves the formation of hydrogen bubbling evolution . Subsequently, a soft curing stage at 60°C for 24 h was carried out in an oven to complete foaming and compound reaction.…”

Micro‐tomographic characterization of composite recycled glass‐silicone foams for applications in civil engineering

“…The strong chemical interaction between the two components is a stimulus to identify their potential effective combination aimed to obtain a performing composite material in terms of physical–mechanical properties. For this purpose, a fundamental topic is offered by the morphology of the cellular structure of the composite foam, which plays a key role in the durability and stability of the foam itself . The definition and discrimination of the main morphometric parameters of the foam and how these vary according to the synthesis conditions is a relevant aspect that needs to be investigated for its optimization during the experimental research and development.…”