A bioassay for the possible carcinogenicity of 3,3'-dimethoxybenzidine-4,4'-diisocyanate was conducted using Fischer 344 rats and B6C3F1 mice. 3,3'-Dimethoxybenzidine-4,4'-diisocyanate was administered, at either of two concentrations, to groups of 50 male and 50 female animals of each species, with the exception of 49 high dose female rats. The compound was administered in the feed with the ex...

As part of the Survey of Painters and Repairers of Auto bodies by Yale (SPRAY), the determinants of isocyanate exposure in auto body repair shops were evaluated. Measurements (n = 380) of hexamethylene diisocyanate-based monomer and polyisocyanate and isophorone diisocyanate-based polyisocyanate were collected from 33 auto body shops. The median total reactive isocyanate concentrations expresse...

Diisocyanates (dNCOs) are low molecular weight chemical sensitizers that react with autologous proteins to produce neoantigens. dNCO-haptenated proteins have been used as immunogens for generation of dNCO-specific antibodies and as antigens to screen for dNCO-specific antibodies in exposed individuals. Detection of dNCO-specific antibodies in exposed individuals for diagnosis of dNCO asthma has...

As petroleum feedstocks start to dwindle, it is becoming more important to find acceptable replacements for materials made from these feedstocks. Polyurethanes have classically been synthesized from petroleum-based feedstocks, and depending on its properties, polyurethanes can be used in everything from foams, to construction plastics. In recent years there has been an increasing amount of rese...

Hexamethylene diisocyanate (HDI) is used widely to manufacture polyurethanes for paints and coatings. It is an irritant and a chemical asthmagen. The U.S. Occupational Safety and Health Administration time-weighted average permissible exposure limit is 5 ppb and the ceiling limit is 20 ppb. We sought to develop a sensitive and specific immuno-bioassay to supplement workplace air monitoring and ...

Polyurethanes and polyurethane-ureas were prepared by the reaction of diethylene glycol and polyethylene glycol with excess of aromatic and aliphatic diisocyanate to yield isocyanate terminated prepolymers which were subsequently reacted with diols and diamines. These polymers were characterized by IR, 1HNMR spectra, viscosity measurements and thermogravimetric analysis.

A series of polyurethane elastomers based on an aliphatic diisocyanate and a polyether macroglycol was polymerized with various cross-link densities and OH/NCO ratios. Stoichiometries yielding between 8,600 and 12,900 gm/mole/crosslink and an OH/NCO ratio of 1.1 resulted in polymers with the low modulus, yet high strength and elongation necessary for maxillofacial applications.

Inhalation challenges to isocyanates are conducted in specialized centers to confirm occupational asthma. The pattern of asthmatic reactions due to consecutively increasing daily doses of isocyanates is unknown. We conducted a study involving 24 subjects who had undergone specific inhalation challenges to isocyanates (toluene diisocyanate [TDI], n = 8; hexamethylene diisocyanate [HDI], n = 10; ...

In this work, 5,6,7,8-Tetrabromo-2,3-dihydro-2,3-bis(2-hydroxyethyl)phthalazine-1,4-dione is synthesized by the reaction of 5,6,7,8-tetrabromo-2,3-dihydrophthalazine-1,4-dione with 2-bromoethanol in the presence of triethylamine. The obtained monomer was polymerized with different diisocyanates, including hexamethylenediisocyanate (HMDI), tolylene-2,4-diisocyanate (TDI), isophoronediisocyanate ...