Phenol-formaldehyde foam properties

The friability of a rigid foam is not an easy property to determine, and it is seldom used as a quality control measurement. However, for certain materials such as phenol-formaldehyde foam it can be a useful tool in formulation work to ensure that the product is suitable for the application area. In certain instances the test method is best adapted to the foam being tested, for example the time duration of the test may be shortened if the material is being abraded too harshly. 

Foams prepared from phenol—formaldehyde and urea—formaldehyde resins are the only commercial foams that are significantly affected by water (22). Polyurethane foams exhibit a deterioration of properties when subjected to a combination of light, moisture, and heat aging polyester-based foam shows much less hydrolytic stabUity than polyether-based foam (50,199). 

Phenol—formaldehyde resins are used as mol ding compounds (see Phenolic resins). Their thermal and electrical properties allow use in electrical, automotive, and kitchen parts. Other uses for phenol—formaldehyde resins include phenoHc foam insulation, foundry mold binders, decorative and industrial laminates, and binders for insulating materials. 

Mixtures of rubber latices or elastomer foams were modified with colloidal silica to give improved properties. Typical processes involved drying, gelling, or coagulating the colloidal silica within the elastomer system. Silica sols were used with phenolic, formaldehyde-based, melamine, polyester, acrylic, vinyl or styrene polymer-copolymer, polyamide, and styrene-butadiene rubber systems to provide strength to films and coatings. 

The Mannich polyols described are aromatic aminic polyols, the aromatic rings have a real contribution in improving the physico-mechanical, thermal and fire proofing properties of the resulting rigid polyurethane (PU) foams. The Mannich bases, for example the Mannich base resulting from one mol of nonyl-phenol, 2 mols of formaldehyde and 2 mols of... 

Urea-formaldehyde resins are applied in the field of electronics. They possess superior electrical insulation properties compared to phenolic resins and are used in the production of mainly sockets, plugs and switches. A special application of urea-formaldehyde resins consists in the obtaining of foams for placing on airport... 

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