Extruded polymeric foam

The use of cellular plastics for wall and ceiling insulation of residential buildings has increased more than 200 % over the past decade. Extruded polymeric foam is found in residential construction as sheathing, perimeter and floor insulation under concrete, and combined plaster base and insulation for walls. Both polystyrene and polyurethane foams are highly desirable roof insulants. 

This compound is usually made and used in situ. A 5 g sample was allowed to sit in a screw top vial for a couple of days, one morning it was found to have blown a hole in the lid and extruded a 20 ml plume of polymeric foam [1], An attempt to dry anisyl chloride over molecular sieves pressurised the container, presumably with hydrogen chloride evolved during polymerisation [2],... 

Examples are given of the use of extruded PE foam sections in conjunction with other polymeric materials in the production of triangular, semicircular, rectangular and trapezoidal profiles, e.g. beam-like structures in which the rigid support may be of GRP. The foam can be bonded with thermally-fusible adhesives or two-sided self adhesive tape affixed to the foam prior to fabricating. A standard range of the foam prodncts is available, but other types can be tailor-made. 

The product of a successful suspension polymerization is small, uniform polymer spheres. For certain applications, they are used directly, eg, as the precursors for ion-exchange resins or bead foams. For others, they may be extruded and chopped to form larger, more easily handled molding pellets. 

The liquid monomers are suitable for bulk polymerization processes. The reaction can he conducted in a mold (casting, reaction injection molding), continuously on a conveyor (block and panel foam production), or in an extruder (thermoplastic polyurethane elastomers and engineering thermoplastics). Also, spraying of the monomers onto the surface of suitable substrates provides insulation barriers or cross-linked coatings. 

Hazardous Decomp. Prods. Heated to decomp., emits toxic fumes of POx Uses Flame retardant, plasticizer for PVC, cellulose nitrate, CAB, ethyl cellulose, polymethyl methacrylate, PS, buna N rubber, in vinyl film and sheeting, textile coatings, plastisols, organosols, adhesives, pkg. materials plasticizer in food-contact coatings, dip, rotationally, extruded and inj. molded parts, mech. foam in food-pkg. adhesives in resinous/polymeric food-contact coatings Features Low-temp, plasticizer Regulatory FDA 21CFR 175.105, 175.300, 175.320, 181.27 Manuf./Distrib. Akzo Nobel http //www.akzonobel.com, Ashland http //www.ashchem.com, Bayer http //www.bayerus.com, Monsanto http //www.monsanto. com,... 

PS (Poly.stvrene) Polymers of styrene (vinyl benzene). PS is somewhat brittle and is often copolymerized or blended with other materials to obtain desired properties. HIPS (high impact PS) is made by adding rubber or butadiene copolymers. Commonly known PS foams are produced by incorporating a blowing agent during the polymerization process or injecting a volatile liquid into molten PS in an extruder. 

The polymerization step can be conducted in a mold, in an extruder (TPU production), or continuously on a conveyor (block foam production). Also, spraying... 

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