Synthesis and Properties of Alphatic Polyurethanes and Model Compounds Containing Alpha, Alpha, Alpha Prime, Alpha Prime - Tetramethyl-p-Xylylene-Diisocyanate.
Abstract
New materials are needed to replace the rubber compounds which are in current use in certain high stress environments. The rubber materials usually fail due to the high internal temperature which results from compressive cycling under heavy loads. Rubber formulations, such as styrene-butadiene, also fail due to severe mechanical stresses, such as tearing forces. Polyurethanes are being examined as possible replacements due to indications of better mechanical strength. However, hysteric heat buildup in polyurethanes is a major problem. Investigation of the molecular arrangement of the polyurethane samples was made using infrared and X-ray scattering techniques. Low molecular weight model compounds, simulating the polar regions of the polyurethanes, were prepared and characterized by single crystal X-ray diffraction by Dr. Jerry P. Jasinski. Compressive fatigue tests were conducted on some samples which showed good thermal resistance by other tests. The model compounds of p-TMXSI provided information on the possible conformation of this unique structure in the polyurethane chains. Until recently, polyurethanes made from diphenylmethane-4,4'-diisocyanate were the only polyurethane class which had been characterized by X-ray scattering and X-ray crystallographic techniques. Keywords: Polyurethanes, X-ray crystallography, Fatigue (Mechanics); Thermal analysis; Synthetic rubber; Synthesis (Chemistry).
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1987
- Accession Number
- ADA178312
Entities
People
- Brian A. Zentner