Polyetherimide production methods

Polyether imide is 4,4 '- diaminodiphenyl ether, or a (or) p-phenylenediamine and 2,2' - bis [4 - (3,4 - dicarboxyphenoxy) phenyl] propane dianhydride in dimethylacetamide solvent condensation by heating, into a powder, an imine of the system.

In the above method, the method can be divided into more nitro and polycyclic polycondensation. The former first cyclization reaction of an imide ring, then nitro aromatic nucleophilic substitution reaction, forming the flexible ether "hinge." The latter is the first cyclization, and cyclization reaction, formation of polymers polycyclic polycondensation step.

PEI can be prepared by melt polycondensation. This approach from the economic, ecological and technical point of view, are promising. Since this method does not use a solvent, the polymer does not contain solvents, which is the processing and use are important.

PEI continuous method can also be used directly in the extruder manufacturing. The method steps are: a mixture of the starting compound passes through the extruder with different temperature zones in the low temperature region to a monomer mixture final product of high temperature melting. Cyclization reaction of water, after appropriate port hole is discharged continuously from the extruder, usually in the final area of ​​the extruder under reduced pressure by vacuum extraction. From the discharge port of the extruder the polymer pellets or sheets can be obtained. But also directly to the extruder and various fillers PEI, PEI-based system with mixing to.

In these methods, the solution polymerization is a method of industrial production. However, continuous extrusion extruder synthetic resin polymerization methods by Shanghai Institute successfully developed small devices that can push industrial production.