Hybrid foams

Dong, X., et al., Synthesis of graphene-carbon nanotube hybrid foam and its use as a novel three-dimensional electrode for electrochemical sensing. Journal of Materials Chemistry,... 

The afterglow of open-cell foams (punking) can be suppressed by the addition of flame-retardants such as boron trioxide or aluminum hydroxide. Hybrid foams with good mechanical properties and low combustibility can be produced from PF resins and polyisocyanates.104... 

Modesti, M. Zanella, L. Lorenzetti, A. Bertani, R. Gleria, M. Thermally stable hybrid foams based on cyclophosphazenes and polymethanes. Polym. Degrad. Stab. 2005, 87, 287. 

Modification of poly(carbodiimide) foams with polyols afford hybride foams containing urethane sections. However, the thermal stabilities of the poly (urethane carbodiimide) foams are lower. Using isocyanate trimerization catalysts, such as l,3,5-tris(3-dimethylaminopropyl)hexahydro-s-triazine, in combination with the phospholene oxide catalyst gives poly(isocyanurate carbodiimide) foams with improved high temperature properties. The cellular poly(carbodiimide) foams derived from PMDI incorporate six-membered ring structures in their network polymer structure. ... 

In addition to these unmodified foams, many modified or hybrid foams have appeared in the literature, e.g., urethane-modified isocyanurate foams, isocyanurate-modified urethane foams, urea-modified isocyanurate foams, unsaturated poIyester-poI)rurethane hybrid foams, etc. 

These foams include isocyanurate-modified rigid urethane foams, isocyanurate-modified flexible urethane foams, urethane-oxazolidone foams, urethane-based IPN foams, and urethane-based hybrid foams. 

Urethane-Based Hybrid Foams. Hydroxyl-terminated ester oligomers or vinyl esters which have terminal vinyl groups and pendant hydroxyl groups can react simultaneously with isocyanate groups and vinyl monomers in the presence of catalysts to obtain crosslinked hybrid polymers. 

Example (3) Vinyl ester-urethane hybrid foams may be prepared according to the model reaction (c) in the presence of a blowing agent such as CFC-11 (55, 127). 

Matrix Plastic Foams. The matrix for plastic foams includes rigid polyurethane foam, urethane-modified isocyanurate foam, unsaturated polyester-polyurethane hybrid foam, and vinyl ester-polyurethane hybrid foam. 

Hydroxyl-Containing Unsaturated Compounds/Polyurethane Hybrid Foams. Unsaturated polyesters have terminal hydroxyl groups and unsaturated linkages in the polymer skeleton (34). Vinyl esters have terminal vinyl groups and pendant hydroxyl groups. These model structures are shown in Equations (1) and (2) respectively. 

Mazzola et al used polyesters for foamed composites (6). Narkis et al (27) described foamed polyester composites made using random glass mat. Saidla et al (28) reported making foamed polyester composites using -inch glass fibers. Vinyl ester/styrene copolymer foams were developed by Olstowski and Perrish (10, 11). Vinyl ester-based hybrid-foam composites were developed by Frisch and Ashida (19). 

The same company has developed a new generation of highly flame resistant open cell flexible PU/CR hybrid foam materials. The polyurethane and chloroprene are prepared using a brand-new technology called Foam-One. This is a batch process for making flexible slabstock under variable pressure that may range from 1 psi to 25 psi. PU base foams are post-treated with a polychloroprene compound to obtain the hybrid grades. 

Hyrizon, Polyester-polyurethane hybrid foam system, Aristech Acrylics LLC... 

We proceeded in using the toll manufactured RBI-201 material in hybrid PU/RB1-201 polymer foam formulation, and details of the foaming procedure is shown in Fig. 4.5.5. We noted that this toll manufactured RBl-201 was readily dispersed in THF and it can be reasonably dispersed in the polyol of the PU formulation. Thus, foam samples were made from the flow hybrid foaming process as well. The PU formulation employed was the so-called Tigerfoam system. 

Table 4.5.4 Quantitative determination of improvements in thermal properties of the hybrid foam material relative to various references, based on DSC/TGA analysis...

Hybrid foams catalytic performances Esterification Hydrolysis T ransesterification ... 

Figure 43.8 Photograph of a class II silica/ gelatin (60wt% functionalized gelatin) hybrid foam scaffold. The hybrid has 90% porosity. Covalent coupling between silica and gelatin...

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