Functionalized TPU for advanced media applications

• Published in: Journal of magnetism and magnetic materials Vol. 155; no. 1; pp. 73 - 76
• Main Authors: Kim, K.J., Vedula, R.R., Glasgow, P.D., Jacobs, P., Farkas, J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-03-1996
• DOI: 10.1016/0304-8853(95)00677-X
• ISSN: 0304-8853

Model polymers were prepared using phosphate functional groups to investigate the interaction to MP surface which has basic surface finish, pH in 8–10 range. The effects of the level of FG and subsequent polymer molecular weights on the dispersion and the viscosity of the dispersion were studied in reference to the polymer conformation and molecular structure in optimizing the performance of the binder polymer for advanced magnetic media design. The analysis showed that the stability ratio, defined by the ratio of the unstabilized dispersion viscosity to that of the stabilized dispersion, depended on the power law of the
M
w of the polymer with the exponent 0.1–0.2 and 0.5 for stable and unstable dispersion, respectively. The power law dependence with different exponents was interpreted as the conformational differences on the pigment surface in the dispersion. From this analysis, it was indicated that the
M
w of a polymer giving a stable dispersion should be above 10 000. The concept of critical
M
w for a stable dispersion is discussed in reference to the steric stabilization by the polymer layer anchored on the pigment surfaces.