Improved processing of thermotropic liquid crystalline polyesters

A series of thermotropic liquid crystalline polyesters based onp‐hydroxybenzoic acid, terephthalic acid, 2,6‐dihydroxynaphthalene and containing small amounts of either Bisphenol A, 2,7‐dihydroxynaphthalene, or polyethylene terephthalate (PET) as comonomers were prepared. The latter three materials were investigated as a means of lowering the spinning temperature of the base polymer without sacrificing properties. Samples containing 1–2.5% Bisphenol A or 2.5–5% 2,7‐dihydroxynaphthalene retained most of the properties (modulus fell slightly), but spinning temperature reduction was minimal. Polymers containing 2.5–5% PET retained full properties at spinning temperatures 60–80°C below the control.