Branchpoint, preparation

Together with BTCA, TPA and NTPA, these monomers were reacted with amine-bearing monomers, such as 4,4 -diaminobenzanilide (DABA) (number II in Scheme 2) and 1,4-phenyIenediamine, to create most of the rigid polyamide networks prepared by Aharoni and associates [212, 311, 312, 393, 400, 409-411]. Networks with stiff segments between branchpoints as long as 208 A [400] and as short as 6.5 A [311] were prepared, the latter from equimolar mixture of the trifunctional monomers 5-aminoisophathalic acid and 3,5-diaminobenzoic acid ... 

To the best of our knowledge, no fully aromatic polyester networks have been reported in the literature until now. Several reports appeared describing the preparation of liquid crystal thermosets from rodlike polyester segments and branchpoints or junctions created by the reaction of reactive end-caps with one another [417-419]. These end-capped polyester networks will be discussed, however, with all other fully or mostly aromatic networks made in two steps by reacting the end-caps of stiff segments with each other. 

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