ISSN:
1435-1536
Keywords:
Grafting
;
polypropylene glycol
;
ultrafine ferrite
;
isocyanate group
;
dispersibility
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The grafting of polypropylene glycol (PPG) onto an ultrafine ferrite by the reaction of hydroxyl groups on the surface with isocyanate-capped PPG (PPG-NCO), prepared by the reaction of an equimolecular amount of PPG with tolylene 2,4-diisocyanate, was investigated. When PPG-NCO (M n=2.5×103) was heated with the ferrite in bulk, the percentage of grafting onto the ferrite at 120 °C was increased up to 18.5%. On the contrary, the grafting by the reaction of PPG with hydroxyl groups on the ferrite at 120°C was scarcely observed. The grafted PPG onto the ferrite was removed by hydrolysis with a dilute methanol solution of potassium hydroxide. Therefore, it was considered that PPG was grafted onto the ferrite surface with urethane bond. The grafting of PPG onto the surface was also confirmed by infrared spectra. The reaction of PPG-NCO with the ferrite was accelerated by the addition ofα-picoline as a catalyst. PPG-grafted ferrite was found to produce a stable colloidal dispersion in organic solvents. Furthermore, the effect of molecular weight of PPG-NCO on the grafting onto the ferrite was discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01416057
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