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Experimental Study on the Swelling Behavior of Polymer Networks in a Nematic Solvent
Author(s) -
Bouchikhi N,
AlachaherBedjaoui L,
Bouchaour T.,
Tabieguia G.J. Fossi,
Maschke U.
Publication year - 2014
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.201300017
Subject(s) - liquid crystal , differential scanning calorimetry , swelling , materials science , polymer , mesogen , solvent , phase (matter) , polymer chemistry , monomer , chemical engineering , acrylic acid , organic chemistry , composite material , chemistry , thermodynamics , liquid crystalline , physics , optoelectronics , engineering
Summary Swelling properties and phase diagrams of binary systems composed of polyacrylate networks and a low molecular mass liquid crystal (LMWLC) have been investigated. The networks were prepared by ultraviolet (UV) irradiation of reactive mixtures including a monomer, a crosslinking agent and a photo‐initiator. Poly(n‐butylacrylate) networks were prepared using two crosslinking agents: 1,6‐hexanedioldiacrylate (HDDA) and a mesogenic acrylic acid 6‐(4'‐(6‐acryloyloxy‐hexyloxy)biphenyl‐4‐yl oxy) hexyl ester (AHBH). The obtained dry polyacrylates were characterized by differential scanning calorimetry, and immersed in an excess of a LMWLC solvent 4‐cyano‐4'‐pentylbiphenyl (5CB), forming polymer gels. A detailed study by polarized optical microscopy allowed to determine the swelling degree of the gels and to follow the phase behavior of the solvent inside the polymer matrix in a wide range of temperature. Swelling data were used to establish the phase diagrams in terms of composition and temperature. It was found that the poly(n‐butylacrylate) network obtained with the nematic crosslinking agent show fluctuations in the region of the nematic‐isotropic transition temperature of 5CB, probably due to the presence of nematic‐nematic coupling effects between the nematic solvent and the nematic moieties of AHBH.