1.6- hexamethylene diisocyanate, chemical

Stmctural and chemical modification of urethane containing polymer matri-ces with macrocycles - calixarenes having reactive hydrazide groups have been carried out and stmcture, physico chemical and sensor properties of polyure-thanesemicarbazides (PUS) synthesised have been studied. The polymers obtained (on the base of polypropylene glycol MM 1000 and polysiloxane diol MM 860, hexamethylene diisocyanate and calixarene dihydrazide) are identified by IR-spectroscopy, size exclusion chromatography (SEC), DSC, WAXS and SAXS methods. 

The effects of chemical structure of diisocyanate component on the hydrolysis of polyurethanes by R. delemar lipase were examined (Figure 8). The rates of hydrolysis of the polyurethanes containing MDI or tolylene-2,U-diisocyanate (TDI) were smaller than that of the polyurethane containing 1,6-hexamethylene-diisocyanate (HDI). 

These experts collectively have knowledge of hexamethylene diisocyanate s physical and chemical properties, toxicokinetics, key health end points, mechanisms of action, human and animal exposure, and quantification of risk to humans. All reviewers were selected in conformity with the conditions for peer review specified in Section 104(i)(13) of the Comprehensive Environmental Response, Compensation, and Liability Act, as amended. 

If you are exposed to hexamethylene diisocyanate, many factors determine whether you ll be harmed. These factors include the dose (how much), the duration (how long), and how you come in contact with it. You must also consider the other chemicals you re exposed to and your age, sex, diet, family traits, lifestyle, and state of health. 

Table 3-2. Chemical Identity of Hexamethylene Diisocyanate Prepolymers...

Chemical name Hexamethylene diisocyanate biuret Hexamethyene diisocyanate trimer... 

Table 3-3. Physical and Chemical Properties of Hexamethylene Diisocyanate...

Hexamethylene diisocyanate is a highly reactive synthetic chemical that is widely used in the production of polyurethane materials. There is no natural somee of HDI. All of the potential exposures to this compound are associated with the production, handling, use, and disposal of HDI and HDI-containing products or materials. Exposures to HDI are often associated with exposures to its prepolymers, especially to a trimeric biinetic prepolymer of HDI (HDI-BT) (see Figure 5-Ia), whieh is widely used as a hardener in automobile and airplane paints, and whieh typieally contains 0.5-1% unreacted HDI (Alexandersson et al. 1987 Hulse 1984 Karol and Hauth 1982). There is evidence that diisocyanate prepolymers may induce asthma at the same or greater frequency as the monomers (Seguin et al. 1987) therefore, there is a need to assess the potential for human exposme to prepolymeric HDI as well as monomeric HDI. Except for limited data on occupational exposures, no information was foimd in the available literature related to the potential for human exposure to prepolymers of HDI. 

CMA Personal Commimication. 1997. Chemical Manufactiu es Association Hexamethylene Diisocyanate panel comments on Draft ATSDR HDI Profile. 

Dow Chemical. 1964. Study in rats methyl isocyanate and hexamethylene diisocyanate. International Research Development Corporation. EPA/OTS 86-870002225. 

Union Carbide also patented a phosgene-free process for making hexamethylene diisocyanates [40] (Scheme5.5). In this later process, 1,6-hexanediamine was reacted with dry-ice, trimethylchlorosilane, and trichlorophenylsilane to form a halosilyl carbamate intermediate and then converted to the corresponding diisocyanate. However, it should be noted that trichlorophenylsilane used in this process is on the EPA s Extremely Hazardous Chemicals List (40 CFR Part 355, Appendix A). 

A guinea pig inhalation model was developed by Karol (1983) to examine immune and pulmonary responses to TDI. Since that time, this model has been used by other investigators to examine immune and pulmonary responses to TDI and other chemical respiratory allergens such as diphenylmethane diisocyanate (MDI) (Karol and Thome, 1988), trimeric hexamethylene diisocyanate (Des-N) (Pauluhn and Eben, 1991), trimellitic anhydride (TMA) (Botham el al., 1988 Pauluhn and Eben,... 

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