Polymer-dispersed liquid-crystal polymers (PDLCPs). Morphology of the LCP droplets

• Published in: Polymer engineering and science Vol. 39; no. 10; pp. 1891 - 1902
• Main Authors: Magagnini, Pierluigi, Paci, Massimo, Poli, Giovanna, Tonti, Maria Silvia, Narducci, Piero
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.10.1999; Wiley Subscription Services; Society of Plastics Engineers, Inc; Blackwell Publishing Ltd
• Subjects: Applied sciences; Chemical modifications; Chemical reactions and properties; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Polymer liquid crystals; Ethylene terephthalate polymer; Sebacate copolymer; Thermotropic state; Temperature effect; Benzoate(hydroxy) copolymer; Transesterification; Experimental study; Structure composition relationship; Structure processing relationship; Ester copolymer; Chemical modification; Polymer dispersed liquid crystals; Liquid crystal polymers; Nematic state; Morphology; Ethylene terephthalate copolymer
• ISSN: 0032-3888; 1548-2634
• DOI: 10.1002/pen.11582

“Synthetic blends” of a flexible polymer forming the matrix and a liquid‐crystalline polymer (LCP) forming the dispersed phase have been prepared by transesterification of PET with a mixture of sebacic acid (S), 4,4′‐diacetoxybiphenyl (B) and 4‐acetoxybenzoic acid (H) in the mole ratio 1:1:2. A change of the synthesis conditions causes marked variations of the chemical composition and the morphology of the phases. The SEM investigation of the inner morphology of the LCP droplets of blends consisting of two phases with fairly different aromatic content has shown that the LCP macromolecules are aligned tangentially at the matrix surface boundary, and that the nematic director configuration is toroidal. When the two phases have closer chemical composition, and are therefore supposed to possess improved mutual compatibility, a perpendicular anchoring of the LCP fibrils to the matrix cavity surface, and an axial configuration of the nematic director, are observed. The expected effect of the nematic configuration of the LCP droplets on their ability to deform into fibrils under appropriate flow conditions is preliminarily discussed.