Polyurethane foam peroxidation

P.R.208 is also used in polyacrylonitrile spin dyeing. It exhibits excellent textile fastness properties and shows good lightfastness. Full shades (3% pigment concentration) equal step 7 on the Blue Scale, while very light (0.1% pigment) red specimens match step 5. The list of applications includes secondary acetate spin dyeing and mass coloration of polyurethane foam and elastomers. P.R.208 is inert to peroxides. 

Chlorinated paraffins, which contain up to 60-70% chlorine, are low in cost and are used as secondary plasticizer in PVC wire and cable insulations. Perchlorobicyclopentadiene has little plasticizing action and is used in polyethylene. Some of the more expensive bromine-containing fire retardants which have been used in the ratio of 5 p.p.h. in polystyrene foam, may be reduced to 0.5 p.p.h. by adding synergists such as peroxides or nitroso compounds. The reaction-type retardants, such as chlorendic acid and anhydride, hydroxy-terminated phosphonated esters, and specific brominated aliphatic esters, are admixed to rigid and flexible polyurethane foams, reinforced polyesters, phenolics, and epoxy resins. 

The requirements of flexible polyurethane slabstock foam manufachirers vary due to sensitivity to antioxidant volatility, preference in physical form (liquid or sohd), and degree of anti-scorch protection. As a result of this broad variation in antioxidant performance demands, several alternative antioxidants to BHT are available. AO-2 and AO-3 combine relatively low volatility and good anti-scorch performance with the advantage of a liquid product form. AO-4 and AO-5 have significantly lower volatility than BHT and improved performance. Addition of peroxide scavengers such as DTDTDP and PHOS-1 can further enhance the scorch resistance of the polyurethane foam. 

Adipic acid (n=4) Despite its name (in Latin adipis is fat), this acid (hexanedioic acid) is not a normal constituent of natural lipids but is a product of oxidative rancidity (lipid peroxidation). It was obtained by oxidation of castor oil with nitric acid (splitting of the carbon chain close to the OH group). Synthesized in 1902 from tetramethylene bromide, it is now obtained by oxidation of cyclohexanol or cyclohexane. It has several industrial uses in the production of adhesives, plasticizers, gelatinizing agents, hydraulic fluids, lubricants, emollients, as an additive in the manufacture of some form of nylon (nylon-6,6), polyurethane foams, leather tanning, urethane and also as an acidulant in foods. Adipic acid is used after esterification with various groups such as dicapryl, di(ethylhexyl), diisobutyl, and diisodecyl. 

The overwhelming majority of foams are TPs, but TSs are also foamed with CBAs, although some of them do create problems. Popular TS foams are made from polyurethane, polyester, phenolic, epoxy, and rubber. Thermal decomposition of the blowing agent with certain plastics such as TS polyesters cannot be applied in this system because the heat of polymerization is not high enough to induce decomposition. But chemical reactions simultaneously produce gas and free radicals they typically involve oxidation and reduction of a hydrazine derivative and peroxide. The reactions are catalyzed by metals, which can be used repeatedly. 

Aromatic urethanes have been stabilized by complexation of peroxides in the polymer and the effect of prior y-irradiation has been investigated, on polyurethanes.The ageing of polyurethane coatings has been investigated, and light-stable integral skin foams have been developed for polyurethanes. Creep behaviour of polyurethanes on ultraviolet exposure has also been investigated. ... 

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