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Diisocyanato dicyclohexylmethane: structure/property relationships of its geometrical isomers in polyurethane elastomers (1992)

Seneker, S. D. ; Born, L. ; Schmelzer, H. G. ; [et al.]

Springer

Colloid & polymer science 270 (1992), S. 543-548

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ISSN: 1435-1536

Keywords: Diisocyanato dicyclohexylmethane ; polyurethane elastomer ; x-ray diffraction ; dynamic mechanical spectroscopy ; solvent resistance ; mechanical properties

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Notes: Abstract 4,4′-Diisocyanato dicyclohexylmethane (HMDI) is a commercially available diisocyanate used as a building block for polyurethane products that require excellent light stability and hydrolysis resistance. It consists of a mixture of three geometrical isomers, the trans,trans-, cis,trans-, and cis,cis-isomers. We found that the trans,trans-isomer leads to some interesting properties in polyurethane elastomers. Surprisingly, the hardness and percent elongation (properties that usually follow an inverse relationship) both increase with increasing trans,trans- HMDI contents. We also observed dramatic increases in the ultimate tensile strength, split-tear strength, resilience, and solvent resistance. Also, the melting temperature of the elastomers increases with increasing trans,trans content. X-ray analysis of model hard segments showed that the hard segment based ont,t-HMDI is highly ordered, leading to higher melting temperatures and better separation between the hard- and soft-segment phases.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00658285

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Preparation, Properties and Reactions of Polychloroamine Derivatives (1968)

Holtschmidt, H. ; Degener, E. ; Schmelzer, H.-G. ; [et al.]

Weinheim : Wiley-Blackwell

Angewandte Chemie International Edition in English 7 (1968), S. 856-867

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ISSN: 0570-0833

Keywords: Polychloroamines ; Chloroamines ; Amines ; Chlorination ; Synthetic methods ; Chemistry ; General Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Highly chlorinated amine derivatives can be prepared by the high-temperature chlorination of amines and amine derivatives. Essential for the success of this reaction is an adequate temperature control suited to the constitution of the amines. In many cases the chlorination products achieve stability by cleavage reactions with formation of the imidic acid chloride or isocyanide dichloride grouping. Cyclic compounds are formed under special conditions. The chlorination process described can be used to obtain e.g. polychloroaryl and polychloroalkyl isocyanide dichlorides, polychloroaryl and polychloroalkyl imidic acid chlorides, and polychloroheterocyclic compounds.