A novel thermotropic side-chain liquid crystalline ionomer (LCI) containing sulfonic acid groups on the side-chain was synthesized by graft copolymerization of mesogenic monomer 4-allyloxy-benzoxy-4*-methoxyphenyl (ABM) and nonemesogenic monomer 4-allyloxy-azobenzene sulfonic acid (AABS) upon polymethylhydrosiloxane (PMHS). The chemical structures of the polymers were confirmed by IR spectroscopy. DSC and TGA were used to measure the thermal properties of those polymers and the mesogenic properties were characterized by polarized optical micrography (POM), DSC, and WAXD. The clearing point temperature (Tc) of these liquid crystalline ionomers was enhanced 50-607C compared with the polymer without ionic groups. The LCIs exhibit a broad smectic mesogenic region of 80-907C; the thermal stability below 2007C of the polymers decreases with increasing sulfonic acid concentration. The inherent viscosity of 0.5% solutions decreased with increasing sulfonic acid concentration in the polymer chains.

A new series of network liquid crystal polymers were synthesized by graft copolymerization of the difunctional mesogenic monomer 4-allyloxy-benzoyloxy-4'-allyloxybiphenyl (M) upon polymethylhydrosiloxane (PMHS). MonomerMacted not only as a mesogenic unit but also as a crosslinker for the network polymers. The chemical structures of the polymers were confirmed by IR spectroscopy. DSC, TGA, and X-ray scattering were used to measure their thermal properties and mesogenic properties. The glass transition temperature (Tg) of these network liquid crystal polymers was increased when the monomer was increased, and Td (temperature of 5%weight loss) at first went up and reached a maximumat P1, then went down. The slightly crosslinked polymers (P0, P1) show rubber-like elasticity, so it was called liquid-crystal elastomer. Network polymers will lose elasticity property with a highly crosslinked degree, and turn into thermosetting polymers (P4, P5). All polymers exhibited a smectic texture by X-ray scattering.

Liquid crystalline ionomers containing sulfonate groups on the terminal unit of the chain were synthesized by an interfacial condensation reaction of 4,4'-dihydroxy-a,a'-dimethyl benzalazine, the monofunctional dye fast yellow (FY), and a 50/50 mixture of sebacoyl and dodecanedioyl dichlorides. The weight-average molecular weights were estimated from inherent viscosity measurements to be between 6000-11,000 and the sodium sulfonate concentrations ranged from 0-18.4meq/100g polymer. Elemental analyses, however, indicated much higher molecular weights, which suggested that there was a distribution of chains with one, two, or no FY endgroups. The polymers were semicrystalline and melted at ca. 140℃ to form nematic mesophases that were stable over a temperature range of ca. 80℃. They were thermally stable to about 350℃. The ionomeric nature of the polymers was confirmed by the presence of intermolecular associations in nonpolar solvents, as demonstrated by dilute solution viscosity measurements.

A series of siloxane-based liquid-crystalline (LC) elastomers were synthesized by using chemical crosslinking agents containing sulfonic acid groups. The crosslink densities of the elastomers were determined by swelling experiments. Two kinds of melting temperature corresponding to crystallization of siloxane matrix and crystallization of LC segments were clearly detected. Some of the polymers exhibited smectic mesophase textures or cholesteric mesophase textures. A proposed model containing LC segment structure and ionic crosslinking lamellar structure separated by siloxane chains was given. The ion aggregated in domains forces the siloxane chains to fold and form an irregular lamellar structure. Ionic aggregates and LC segments may be dispersed each other to form multiple blocks with increasing ionic crosslinking content.

The miscibility and mechanical properties of the blends of polybutylene terephthalate (PBT) and polypropylene (PP) with a liquid crystalline ionomer (LCI) containing a sulfonate group on the terminal unit as a compatibilizer were assessed. SEMand optical microscopy (POM) were used to examine the morphology of blends of PBT/PP compatibilized by LCI. DSC and TGA were used to discuss the thermal properties of PBT/PP blends with LCI and without LCI. The experimental results revealed that the LCI component affect, to a great extent, the miscibility and crystallization process and mechanical property of PBT/PP blends. The fact is that increasing LCI did improve miscibility of PBT/PP blends and the addition of 1%LCI to the PBT/PP blends increased the ultimate tensile strength and the ultimate elongation.