The synthesis of poly(m‐phenyleneisophthalamide) was performed by thermal solid‐phase polymerization from isophthalic acid and m‐phenylenediamine without using any solvents or condensation agents. The two‐stage heating process was conducted. The oligo(m‐phenyleneisophthalamide) was first synthesized at a relatively low temperature (260 °C for 1 h), followed by the polycondensation at 400 °C for 1 min under reduced pressure to produce the aramid with an inherent viscosity of 0.55 dL/g.

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ABSTRACT:The direct polycondensation of isophthalic acid with a mixture of 1,3-phenylenediamine (m-PDA) and 3,4 0 -diaminodiphenyl ether (3,4 0 -ODA) could be successfully performed in the bulk to afford the expected co-aramids for the first time. The co-aramids with low molecular weights and 3,4 0 -ODA contents higher than 50 mol% display excellent thermoplasticity and melt-drawing property. Indeed, several meters long filaments with 12 lm diameter could be produced. In addition, the environmentally friendly method for the preparation of aramid materials as well as the demonstration of their filament formation will open up the new possibility to prepare aramid fibers.