Foamed composites

In other surfactant uses, dodecanol—tetradecanol is employed to prepare porous concrete (39), stearyl alcohol is used to make a polymer concrete (40), and lauryl alcohol is utilized for froth flotation of ores (41). A foamed composition of hexadecanol is used for textile printing (42) and a foamed composition of octadecanol is used for coating polymers (43). On the other hand, foam is controUed by detergent range alcohols in appHcations by lauryl alcohol in steel cleaning (44), by octadecanol in a detergent composition (45), and by eicosanol—docosanol in various systems (46). 

Chlorine dioxide gas generated from chlorite has been used as a chemosterilizing agent substitute for ethylene oxide in medical appHcations (174,175). Aqueous foam compositions containing chlorine dioxide have also been developed for the sanitization of hard surfaces (176). 

But high stiffness is not always what you want. Cushions, packaging and crashpadding require materials with moduli that are lower than those of any solid. This can be done with foams - composites of a solid and a gas - which have properties which can be tailored, with great precision, to match the engineering need. 

L.D. Booth and L.M. Huber, "Bimetallic Bow of Rigid Urethane Foam Composites", Proc. SPI 6th International Conf.. 1983, pp 85-99. 

A foaming composition having a specific pH and containing an ionic surfactant and a polyampholytic polymer whose charge depends on the pH is circulated in a well. By varying the pH, it is possible to destabilize the foam in such a way as to more easily break the foam back at the surface and possibly to recycle the foaming solution [76]. 

Periodically injecting simultaneously or alternately a noncondensable gas and a foaming composition solution containing alkalis, surfactants and polymers to form combined foam or periodically injecting the gas and the foam previously formed from the solution... 

J. F. Argillier and P. Roche. Drilling method using a reversible foaming composition (procede de forage utilisant une composition moussante reversible). Patent EP 1013739, 2000. 

It has been demonstrated that a fabric/foam composite which passes the cigarette test of BS 5852 Part 1 can fail if a strip of viscose Touching is placed along the junction of the vertical and horizontal parts of the test rig. 

Foam compositions, including a latex and a polynitrile oxide such as 2,4,6-triethylbenzene-l,3-dicarbonitrile oxide, or a latex and an epoxy silane, or a latex and a mixture of the two crosslinkers have been prepared (526). The compositions may also contain additional components, including fillers, surfactants, cell detackifiers, froth stabilizers, froth boosters, viscosity reducers, and compounds to improve resilience, and antioxidants. The compositions are particularly useful in the manufacture of flooring, wall covering, shoe lining and nonwoven materials. 

Yang YL, Gupta MC (2005). Novel carbon nanotube-polystyrene foam composites for electromagnetic interference shielding. Nano Lett. 5 2131-2134. 

Furnace black-reinforced EPDM and NBR blends were compounded with different concentrations of azodicarbonamide foaming agent to produce EPDM and NBR foamed composites. All the mechanical parameters measured were found to decrease as the foaming agent concentration and/or temperature increased. The stress-strain results were discussed with reference to the continuum mechanics theory for compressible materials. 16 refs. 

Patent Number US 5776993 A 19980707 THERMOPLASTIC PVC FOAM COMPOSITION Bong Sub Shin Jae Yeon Lee Dong Keun Kim ... 

This invention relates to a thermoplastic foam composition and more particularly to the thermoplastic... 

Patent Number US 5576080 A 19961119 POLYETHYLENIC FOAMING COMPOSITIONS AND MOULDED FOAMS... 

The resulting polymer foam composition is substantially of the closed cell type. This is evidenced by the fact that for equivalent densities, foams of EVA and acid copolymer are found to exhibit lower helium densities than foams of EVA alone. This is an indication that more of the cells in the EVA/acid copolymer foam are closed. Particularly for an acid copolymer content in the range of about 3-15%, the acid copolymer has been observed to be uniformly dispersed within the EVA in micron-sized particles when analyzed by transmission electron microscopy. 

ABS foam compositions have been developed that contain about 10 parts of a foam modifier and 0.5-2.0 parts of a blowing agent. Sodium bicarbonate is a suitable blowing agent. The foaming modifier is preferably adapted to decrease the foam density and to increase the foam swell of the composition (82). In particular, the foam modifier consists of SAN. The ingredients are admixed and then extruded. Articles with a specific gravity of 0.3-0.47 gem-3 are obtained. 

Table III. Factors Involved in Stability of Foam Composition...

The blow ratio Is the ratio of the weight of the unfoamed composition to the weight of an equal volume of the foamed composition. The relationship between air content of a foam, the blow ratio and the foam density Is Illustrated for an unfoamed composition having a density of 1 g/cc in Table V. 

A high blow ratio Is desired since this creates a large volume of foam with respect to the solids. This serves to minimize variation In dry solids add-on due to variances In knife setting or non-uniform pressure between the two horizontal pad rolls. However, the apparent viscosity of the foamed composition Is directly proportional to Its blow ratio (Figure 5) and the fabric weight and construction will dictate the best coating viscosity for that particular fabric. 

The biological oxidation rate of sulfur foam depends on available surface area, temperature) and access of necessary nutrients, as well as on foam composition. Preliminary test data indicate that in all cases the oxidation rate is less than that of elemental sulfur. Soil pH around the foams at Dempster Highway measured two years after installation was never lower than the pH of the surrounding native soil (Figure 3). Sulfur foam s low toxicity is indicated by the LD60 of > 5 gAg (rat) and the 100% survival rate in a fish bioassay with stickleback (96 hr) (8). 

Similar results have been obtained for other foaming compositions [21,44]. These data indicate that Tr coefficients depend slightly on foam expansion ratio but the decrease is almost twice at level H = 2 cm, which means that the foam decay more intensively at its higher... 

The correlation between the volume or stability of the foam and the hydrophile-lipophile balance (HLB) of surfactants or their mixtures is used to generalise the experimental results derived about the stabilising ability of complex foaming compositions or homologues surfactant series. HLB is an important surfactant parameter, characterising the relative... 

The antifoams were studied on a foam from 1% commercial sulphonol solution. The rate of foam breakdown, caused by the antifoam sprayed, is determined by the foam volume destroyed for 1 min and by the lifetime of one half of the foam column. As tests showed the change in the content of the foaming composition affects the activity of the antifoaming agent but the relative foam stability almost does not change. 

We designate as composite (combined) such systems as are formed by combination of growth and addition systems. As a rule, such systems are produced both by the addition of individual elements and through growth of the individual elements (e.g. pore formation or foaming). Composite systems are, for exemple, ceramics, foam glass, fabrics, Gouch filters, membrane filters, most construction materials, metallic or polymeric cakes, etc. 

Foamed composites are lightweight materials reinforced by fibers. Some of the advantages of these materials are excellent strength/weight ratios, workability, excellent corrosion resistance, and design flexibility of molded products. 

The matrix resins for foamed composites include rigid pol)ruretha-nes, unsaturated polyesters, vinyl esters, and their hybrid resins, such as, unsaturated polyester-urethane hybrid resins and vinyl ester-urethane hybrid resins. The reinforcing fibers include glass fibers, carbon fibers, and organic fibers such as polyamide fiber (Kevlar, DuPont), polyamide-... 

Foamed composites appearing on the market include Thermax (Celotex Corp) (35), Elsen Neo-Lumber FFU (Sekisui Chemical Co., Ltd., Japan) (1,3,8,22), Airlite FRU (Nisshinbo Industries, Inc., Japan) (2), and Polywood (Polymetrics, Inc., Michigan, USA) (5). NPC Inc., New Hampshire, USA, has developed foamed composites, a continuous production process, and equipment for the composites (19, 21). Their product is named Synwood. 

Possible applications of foamed composites include buUding insulation, wood substitutes for applications which require corrosion resistance, high physical strength and light weight. Very recently, a large market for foamed composites has appeared in the automotive industry. One example is a door-trim panel (7). 

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). 

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