Modification of PETI-5K imide oligomers: Effect on viscosity

A phenylethynyl (PE) end-capped oligoimide of number average molecular weight M. 5000, known as PETI-5K was modified by: (1) varying molecular weight; (2) addition of phenylethynyl (PE) end-capped reactive diluents to PETI oligomides; (3) incorporation of 1,4-cyclohexanyl diamine with PETI-5K diamines; (4) incorporation of 2,4,5-triaminopyrimidine with PETI-5K; and (5) replacement of the PETI-5 diamines, 3,4'-ODA and APB with 2,2'-bis [4-(4-amino-phenoxy) phenyl] hexafluoropropane (4-BDAF) to determine the effects on glass transition temperature and minimum melt viscosity. All approaches caused a reduction in complex minimum melt viscosity, but the minimum melt temperatures were only sufficiently low enough for the material to have melt stability for a hot-melt coating application in methods (2), (4), and (5). The reduction in the complex minimum melt viscosity of oligomer prepared by method (4) may be due to unreacted monomers and a lower oligomer molecular weight, M-n, than calculated.