| Abstract: | A novel micron‐sized microencapsulated curing accelerator, imidazole (Im), particles, was first prepared by an ultrasound‐assisted dispersing and spray‐drying method and can significantly prolong the shelf life of epoxy resin‐based microelectronic packaging material. The shell of the encapsulated particles was made from ladderlike copoly(phenyloctyl silsesquioxane) (Ph‐Oct‐T), which was synthesized by a “stepwise coupling polymerization” method. Its softening or flowing temperature can be adjusted by changing the composition. Carbon tetrachloride (CCl4) was chosen as both a solvent of the capsular material Ph‐Oct‐T and a suspending/precipitating agent of the fine Im particles. Subsequently, the solution containing Ph‐Oct‐T and suspended Im particles was treated by a spray‐drying process to produce the microencapsulated curing accelerator, Im particles, whose size and appearance was observed by scanning electronic microscopy (SEM). A greatly improved shelf life of the epoxy resin composition containing this microencapsulated curing accelerator was exhibited by curing tests and DSC measurements. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 873–878, 2002 |
