THE PREPARATION, PROPERTIES AND POTENTIAL APPLICATIONS OF DIIMIDE-HYDROGENATED STYRENE-BUTADIENE (HSBR) AND POLYBUTADIENE (HBR) THERMOPLASTIC ELASTOMERS

Our unique diimide-based process for preparing HNBR latex from NBR lat ex without the use of hydrogen, noble metal catalysts or solvents has now been successfully extended to the preparation of hydrogenated ther moplastic elastomers latexes directly from SBR or BR latex precusors.1 Commercially available SBR latex such as SBR 1502 can be readily redu ced to high saturation levels (95+%) via the diimide reduction techniq ue. Latex cast films of the highly reduced elastomer show excellent oz one and oxidation resistance as expected. Unexpectedly however, the hy drogenated polymer films demonstrate high tensile strength and thermop lastic elastomer (TPE) behavior. The TPE properties have been found to be caused by polyethylene crystallites that exist even in the unstret ched 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-method s not normally available to TPEs in bulk form. In this regard, HSBR or HBR could function as superior replacements for natural rubber (NR) l atex in articles such as tubing, gloves, condoms etc., where ozone and oxidation resistance may be required or in applications where good st rength properties coupled with the absence of potentially allergenic p roteins and/or curatives may be desirable. Alternatively, HSBR or HBR latexes may also be conventionally coagulated and processed using stan dard rubber/TPE compounding techniques.