Foams fabrication

Polyurethanes. These polymers can be considered safe for human use. However, exposure to dust, generated in finishing operations, should be avoided. Ventilation, dust masks, and eye protection are recommended in foam fabrication operations. Polyurethane or polyisocyanurate dust may present an explosion risk under certain conditions. Airborne concentrations of 25—30 g/m are required before an explosion occurs. Inhalation of thermal decomposition products of polyurethanes should be avoided because carbon monoxide and hydrogen cyanide are among the many products present. 

It is very hard to determine the burning behavior of upholstered furniture on the basis of the fire characteristics of the foam, fabric, and framing materials and to account for the geometry and configuration of the furniture and how it is ignited. It is much easier to test the entire furniture item. The calorimeter described in the section was developed for this purpose. 

The foam-fabric contact time, or the machine contact time (KCT), is determined by the ratio of the nozzle orifice dimension in the direction of fabric travel to the fabric velocity ... 

National Emission Standards for Hazardous Air Pollutants Flexible Polyurethane Foam Fabrication Operations... 

Inhalation and dermal exposure can occur during the manufacture and use of TDI. Workers and individuals in close proximity to the plant may inhale emissions from urethane foam production manufacturing facilities. It can be present as a unreacted impurity in materials, for example, TDI has been found in a urethane foam fabric coating in a concentration of <200 mgkg h... 

Pollutants Flexible Polyurethane Foam Fabrication Operations... 

The polyether triols are the most important class of polyether polyols and they are used in flexible PU foam fabrication. The majority of polyether triols used in flexible foams are copolymers of PO-EO. Random copolymers are used in continuous slabstock flexible foams and block copolymers (PO-EO), with terminal poly[EO] block, are used in moulded foams (hot moulding and cold cure moulding processes). 

By using, together with a diol, a triol such as TMP or glycerol it is possible to obtain polyesters with a functionality (f) higher than 2 OH groups/mol, situated in the range of 2-3 OH groups/mol. These polyester polyols are used for flexible PU foam fabrication. Flexible PU foams based on polyester polyols have a unique property their clickability (capacity to be easily cut) and are used in laminates for textile industry. 

By chemical recovery of polyester [poly(ethylene terephthalate) (PET)] (Chapter 16) and PU wastes, by alcoholysis or by aminolysis (Chapter 20), new polyols are obtained that can be used in rigid PU foam fabrication. The vegetable oil polyols, obtained by chemical transformation of the double bonds in vegetable oils in various hydroxyl groups are a very attractive route to obtain polyols from renewable resources (Chapter 17). 

Polyether Polyol Technologies for Rigid Foam Fabrication... 

The last traces of alkylene oxides are removed by vacuum distillation at 100-110 °C. After the phenolic group alkoxylation, that is the first group which is alkoxylated, the resulting structure becomes much more stable and it is possible to develop degassing at higher temperature, without the risk of viscosity increase. The resulting Mannich polyols are used in polyurethane foam fabrication without any other supplementary purification. The reactions involved in the alkoxylation of Mannich bases to Mannich polyols are presented in reaction 15.10 [9]. 

A partial esterification reaction takes places (19.5). This side reaction does not have a negative effect on rigid PU foam fabrication because it gives a very convenient tetrafunctional compound, which participates, together with the amidic polyol, to build the crosslinked structure of polyurethane. These compounds containing ester groups are present in low concentrations, maximum 5-7% [1,2]. 

The reaction of polyethylene terephthalate) (PET) with diethanolamine, followed by propoxylation, gives liquid amidic polyols useful in rigid PU foam fabrication. This method is an efficient variant of PET waste chemical recovery (bottles, x-ray films, fibres and so on) [1]. 

Glycolysis of flexible PU foams is also possible. At a ratio of PU waste DEG of 1-1.5 1, two layers are formed (the superior layer being rich in polyether), but at a higher ratio of 2-4 1 a homogeneous polyol mixture results, with an hydroxyl number of 360-390 mg KOH/g, which was used successfully in rigid PU foam fabrication [35]. 

In The Dow Chemical Co. s Plastics Department, we have a Plastics Technical Service (PTS) and a Coatings Technical Service (CTS). One is concerned with those plastics which are readily identified as such, because they are films, sheets, foams, fabricated products, or materials to be molded or extruded. The other deals with monomers and polymers or copolymers which, in resin and latex form, ordinarily lose their identity. Typical applications are in paints, paper coatings, and textile coatings. 

In this context, nanoporous carbons are extremely interesting materials which can be used either as electrodes of supercapacitors or hydrogen reservoir. They are commercially available at a low cost and under various forms (powder, fibers, foams, fabrics, composites) [3]. They can be obtained with well-developed and controlled porosity [4,5] and with a rich surface functionality [6,7], As far as electrochemistry applications are concerned, very important advantages of carbons are a high electrical conductivity, a good chemical stability in various electrolytic media and the possibility to control wettability by the nature of the surface functionality. When they are not playing the role of active material for the storage process, carbons may be also useful as additive in a composite to improve its physical properties. Particularly carbon nanotubes are able to improve the electrical conductivity and mechanical properties of electrodes [8],... 

Condit, D. A., D. Malek, A. D. Cianciolo, and C. H. Hofrichter. 1978. Life hazard evaluation of flexible polyurethane foam/fabric composites typical of cushioned upholstered furniture. 

Chem. Descrip. Vinyl chloride homopolymer Uses PVC for blown foams, fabric coalings, plastisol printing inks Features Med. m.w. provid good balance of fused film physical props, and tusion chars. exc. chem. foam chars, with good oveitlow resist good disp. tor easier plastisol formulation Properties Wh. tine powd. sp. gr. 1.40 bulk dens. 0.34-0.42 g/cm relative vise. 2.34 (1% in cyclohexanone) 0.06% moisture Geon 213 [PolyOne/Specialty Resins]... 

Uses Flame retardant for ABS plastics, coatings, lacquers, PU foams fabrication of business machines, industrial equip., elec, mfg., elec, razors, hand tool housings, projector housings, cinema equip, cases, sm. automotive parts, motor housings, elec, appliances inc. heat stability in thermoplastics... 

Anon., Karl Mayer, Spacer Fabrics - An Alternative to Laminated Foam Fabrics (April 1992). Verkauf Information Service, N. 656, Karl Mayer Textilmaschinenftibric GmbH,Obertshausen, Germany. 

J. Pinto, et al.. Solid skin characterization of PMMA/MAM foams fabricated by gas dissolution foaming over a range of pressures. Defect and Diffusion Forum 326-328 (2012) 434-439. 

Fig. 5. Schematic illustration of the salt-leaching technique for porous foam fabrication.

Fig. 6. SEM micrograph of a PLLA foam fabricated using the salt-leaching technique.

Explosive production Hexible polyurethane foam fabrication 11/15/00 (07/00) (07/01) (FFFF) ... 

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