Ferrocene containing copolymers with improved electrostatic dissipation properties for advanced applications

Polyurethane (PU) and polyimide (PI) copolymers containing a ferrocene oligomer (FcOlig) in the backbone were synthesized and characterized. PU materials with the FcOlig in the chain (PU-FcOlig) demonstrated improved electrostatic dissipation properties and decreased electrical resistance in comparison to the unmodified PU parent material. The surface resistance decreased nearly 30 times and the volume resistance decreased nearly 12 times with a 3.5% FcOlig reacted in with Rubinate (R) 9272. The same 3.5% PU-FcOlig material exhibited an average surface potential resulting from charge deposited of 130 +/- 4 V down from 1600 +/- 65 V for the unmodified PU. The charge dissipation time to 1/e (initial voltage divided by e) was also decreased to 81 +/- 7 msec for 1.5% PU-FcOlig materials from an average of 934 +/- 62 msec for the parent PU. Incorporating the FcOlig into the backbone of a PI (BPDA-ODA PI FcOlig) had no significant effects on the electrical properties in comparison to the unmodified parent PI (BPDA, 3,3 ', 4,4 '-biphenyltetracarboxylic dianhydride; ODA, 3,3 '-oxydianiline). The difference in electrical properties between the ferrocene containing PUs and PIs is the lack of FcOlig blocks on or near the surface of the PI. X-ray photoelectron spectroscopy (XPS) confirms that on the surface of the ferrocene containing PUs iron in the form of ferrocene is detected, but even after etching the PIs to a depth of 50, 100, 50 angstrom, and finally scraping the surface with a scalpel no iron was observed. Published in 2006 by John Wiley & Sons, Ltd.