Hierarchically structured carbon and silica by chemical foaming

Abstract

Foamed organic/silica hybrid materials are synthesized via cationic polymerization of organic carbonates with twin monomers. They are converted into hierarchically structured carbon and silica.

Twin Polymerization: A Unique Strategy towards Versatile Functional Materials

“…In 2018, Spange and coworkers reported the formation of hierarchically structured carbon and silica materials by chemical foaming. [107] In this context, the chemical foaming of inorganicorganic hybrid materials was performed by simultaneous cationic polymerization of the three carbonates difurfuryl carbonate (20), bis(m-methoxybenzyl) carbonate ( 21 Within this procedure organic-SiO 2 hybrid foams under high volume enlargement within the monomer melt were accessible. Due to CO 2 release thru the cationic polymerization process of the organic carbonates and the associated increase of viscosity via polymerization of the appropriate twin monomers, a macroscopic structure could be realized by the chemical foaming procedure.…”

“…The corresponding pore walls comprise of the characteristic nanostructure of TP, which was proven by converting the hybrid material foams into micro-and mesoporous C and SiO 2 foams. [107] Within these studies the authors were able to demonstrate that the key feature for producing the corresponding foamy products with the targeted chemical and physical properties is the adjustment of the organic carbonates' and twin monomers' reactivity of their aromatic functionalities. This could be reached by the direct combination of the respective monomers possessing the same or similar molecular organic groups to suitably polymerize (Scheme 12).…”

“…The authors point out that the concept described above is promising for the accessibility of a number of tailor-made hybrid material foams including different inorganic oxides. [107] The combination of NP-loaded materials and foams via TP, in order to create supported and through macropores easily accessible NPs, is a reasonable next step to extend this field towards, e. g. heterogeneous catalysis.…”

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

“…Figure 26: The typical range of foam density and glass transition temperature (Tg) obtained by using self-foaming method presented in the review (when provided). [56][57][58][59]74,75,98,100,105,106,123,126,137,[144][145][146][147][148]158,160,167,170,171,187,190,195,212,214,223,[227][228][229]233,237,[242][243][244]248,251,255] In the context of toxicity concerns related to the use of isocyanates, the other self-foaming techniques described in this review are offering promising alternatives to develop safer and environmentally benign foaming technologies, notably for the sector of PPE. Their transfer to the industry is probably just a question of time and more importantly, cost.…”

In Situ and Intraoperative Detection of the Ureter Injury Using a Highly Sensitive Piezoresistive Sensor with a Tunable Porous Structure

“…Introducing pores into materials can effectively decrease the Young’s modulus. This strategy can be realized by chemical foaming and physical template methods. ,− The size, shape, and distribution of pores prepared by chemical foaming are random because it is difficult to control the chemical reaction precisely . Besides, physical template methods that are based on water/oil emulsion principles are complicated to prepare, and emulsion stability is a significant concern, , while methods that are based on sacrificial templating such as sugar, sodium chloride powders, and nickel foam usually result in random pore size and shape. ,, Hence, the nonuniformity of pores by these methods largely limit the stability and uniformity of the flexible pressure sensor.…”