C. Chovino et al., INFLUENCE OF BACKBONE TACTICITY ON THERMOTROPIC PROPERTIES OF SIDE-CHAIN LIQUID-CRYSTAL POLYMETHACRYLATES, Polymer, 39(25), 1998, pp. 6385-6390
In order to study the tacticity effect of the backbone on the thermotr
opic properties of side-chain Liquid crystalline (SCLC) polymers, the
synthesis of four polymethacrylates with different tacticities and bea
ring methoxy biphenyl mesogenic groups was carried out. Homopolymers w
ere obtained upon photopolymerisation at low temperature of two mesoge
nic methoxy biphenyl monomers, with and without ethylene oxide spacer.
Methacrylic acid copolymers were obtained by grafting the same mesoge
nic groups onto 92% syndiotactic or atactic polymethacrylic acids. It
is demonstrated that an increase of 11% of the content of syndiotactic
triads compared to an atactic structure, does not modify the liquid c
rystal behavior of homopolymers. Indeed, smectic OB, A, E and nematic
phases were identified as for similar atactic samples. On the other ha
nd, with both copolymers, the liquid crystalline behavior disappears t
o the advantage of crystalline phases independently on the backbone co
nfiguration. The results confirm that mesogenic interactions govern th
e structural behavior of such polymethacrylate polymers. (C) 1998 Else
vier Science Ltd. All rights reserved.