• Polymer(Korea)
• /
• v.26 no.4
• /
• pp.523-534
• /
• 2002

A new hydroxypropylcellulose (HPC) capable of exhibiting reflection colours in the temperature ranges of about 60-$130^{\circ}C$ and acrylic acid esters of HPC (ESs) with degree of esterification (DE) ranging from 1 to 3 were synthesized. The crosslinked ES films with the optical pitch ($\lambda_m$) ranging throughout the visible region were also prepared by exposing thermotropic cholesteric phases of ESs with a DE of more than 2 to UV light at $50^{\circ}C$. The thermal and optical properties for both the uncrosslinked and crosslinked samples and the swelling behavior of the crosslinked films in acetone were investigated. The $\lambda_m$'s of ESs, as well as HPC itself, increased with temperature. However, the $\lambda_m$'s of ESs were larger than of HPC at the same temperature and decreased with increasing DE. The temperature dependence of $\lambda_m$of the crosslinked samples was much weaker than that of ESs. Moreover, in contrast with ESs that exhibit a decrease of the isotropization temperature with increase in the DE, the networks were found to decompose at about $210^{\circ}C$, giving no transition to an isotropic state. The crosslinked samples exhibited an anisotropic swelling, suggesting that the two-dimensional crosslinking preferentially performs between ES molecules.