Synthesis And Characterization Of Hydroxypropylcellulosegraft Copolymers

This thesis is about the modification of the biocompatible, biodegradable and thermo-responsive hydroxypropylcellulose (HPC). Firstly, graft copolymers based on HPC with zwitterionic, anionic and cationic side chains were synthesized. Then, the effect of side chains on the thermo-responsibility of HPC-g-PMPC was studied. The main results are listed below:1. Hydroxyproyl cellulose graft poly(2-(methacryloyloxy)ethyl phosphorylcholine) (HPC-g-PMPC) with well-defined architecture was synthesised via atom transfer radical polymerization (ATRP) in water and characterized. Aggregation behavior and thermal sensitivity of the HPC-g-PMPC copolymers with different chain lengths and graft densities were investigated by UV-Vis, differential scanning calorimetry (DSC) and dynamic light scattering (DLS). The results indicated that the low critical solution temperature (LCST) of HPC-g-PMPC in aqueous solution can be efficiently regulated to body temperature region by controlling the graft densities. The biocompatibility and efficiency were estimated by cytotoxicity and phagocytosis test. The cytotoxicity results shown than the HPC-g-PMPC have no cytoxicity to cells which indicated the HPC-g-PMPC have good biocompatibility. The phagocytosis results shown that the HPC-g-PMPC could enter into cells efficiently. This suggested that the HPC-g-PMPC copolymer has the potential applications in biotechnology and medicine.2. Hydroxypropyl cellulose graft poly(acrylic acid) (HPC-g-PAA) with well-defined architecture was synthesised via ATRP and characterized. HPC-g-PAA copolymer could self-assemble into aggregations when the concentration of HPC-g-PAA copolymer rises above the critical aggregation concentration (CAC). The aggregations can adsorb protein by the electrostatic interaction, which indicated its application in protein drugs carrier.3. Hydroxypropyl cellulose graft poly(methacrylatoethyl trimethyl ammonium iodide) (HPC-g-PADMEMA-IM) with well-defined architecture was synthesised via ATRP and characterized. HPC-g-PDMAEMA-IM copolymer could self-assemble into aggregations when the concentration of HPC-g-PDMAEMA-IM copolymer rises above the critical aggregation concentration (CAC). The aggregations can adsorb protein by the electrostatic interaction, which indicated its application in protein drugs carrier.