The Preparation, Properties and Potential Applications of “Diimide-Hydrogenated” Styrene-Butadiene (HSBR) and Polybutadiene (HBR) Thermoplastic Elastomers

Abstract

Abstract Our unique diimide-based process for preparing HNBR latex from NDR latex without the use of hydrogen, noble metal catalysts or solvents has now been successfully extended to the preparation of hydrogenated thermoplastic elastomers latexes directly from SBR or BR latex precusors. Commercially available SBR latex such as SBR 1502 can be readily reduced to high saturation levels (95+%) via the diimide reduction technique. Latex cast films of the highly reduced elastomer show excellent ozone and oxidation resistance as expected. Unexpectedly however, the hydrogenated polymer films demonstrate high tensile strength and thermoplastic elastomer (TPE) behavior. The TPE properties have been found to be caused by polyethylene crystallites that exist even in the unstretched films under ambient conditions. Latex is an unusual physical form for a TPE material. As a latex, TPE elastomers can be fabricated into sheets or other products by simple dipping or spraying methods—methods not normally available to TPEs in bulk form. In this regard, HSBR or HBR could function as superior replacements for natural rubber (NR) latex in articles such as tubing, gloves, condoms etc., where ozone and oxidation resistance may be required or in applications where good strength properties coupled with the absence of potentially allergenic proteins and/or curatives may be desirable. Alternatively, HSBR or HBR latexes may also be conventionally coagulated and processed using standard rubber/TPE compounding techniques.