SYNTHESIS OF MICROCAPSULES FROM PREPOLYURETHANES
Keywords:prepolyurethane, microcapsule, interfacial polymerization.
AbstractPolyurethane (PU) microcapsules containing toluene diisocyanate (TDI) healing agent were synthesized by mixing PU with chain extender ethyleneglycol (EG) via interfacial polymerization of oil–in–water (gum arabic emulsifier). The morphology and size of the capsules greatly depend on a variety of factors including dispersion speed and emulsifier ratio. The preparation of PU prepolymer and microcapsulation of TDI are presented. The diameter of smooth spherical microcapsules ranged from 93, 160 and 239 µm are produced by varying the agitation rate from 800 rpm to 1200 rpm. The core content of microcapsules is influenced by the ratio of chlorobenzene (CB) solvent in oil phase. The microcapsules have about 40.5 wt% of core which are capable of application in self–healing coatings when using 20 wt% CB and 17.5 wt% emulsifer ratio.
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