The gelation mechanism of non-water gel comprising PEG

We have developed a non-water gel comprised of polyethylene glycol (PEG) and hydroxypropylcellulose (HPC) as a gelling agent. We investigated the gelation mechanism of the HPC/PEG system on the basis of a stress-controlled rheometer and an X-ray diffractometer. From these results, we found that two gelation mechanisms coexisted in the HPC/PEG system; the entanglement of interacting HPC polymer chains which behave like a flexible polymer and the cross-linking of the microcrystalline domains of the HPC main chains. In the lower HPC concentration range, the gelation is dominated by the cross-linking of the microcrystalline domains of the HPC main chains. In the higher HPC concentration range, on the other hand, the gelation is dominated by the entanglement of interacting HPC polymer chains.