(121b) Synthesis and Production of Polyimide Fine Beads by the Use of Micro-Flow-Mixing Technique

We wish to present a new synthetic and production methods to get polyimide fine beads with the diameter from submicron to several microns having a coefficient of variation less than 10%. Polyimide itself is well known to have an excellent heat-resistance property. The fine polyimide beads were obtained by thermal dehydration reaction of fine poly(amic acid) beads, which were prepared by mixing tetracarboxylic acid dianhydride solution with diamine solution using micro-flow-mixing devices. When the nucleophilic polymerization reaction proceeded, the resulting polymer aggregated and precipitated to give spherical shaped beads. When the mixing was carried out by a conventional dropping funnel or by a T-shaped mixing device, fine spherical shaped beads were not obtained. Addition of a base during the polymerization reaction, the uniform reaction took place and monodisperse like fine spherical shaped beads were obtained.