SYNTHESIS AND CHARACTERIZATION OF FUNCTIONALIZED FLUORINATED POLYMERS
Open Access
- Author:
- Liang, Siwei
- Graduate Program:
- Materials Science and Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- None
- Committee Members:
- Qing Wang, Thesis Advisor/Co-Advisor
Ralph H Colby, Dissertation Advisor/Co-Advisor - Keywords:
- oligomeric aniline blocks
block copolymer
fluorinated polymers - Abstract:
- A series of benzoyl peroxide (BPO) derivatives with different substituents, such as protected hydroxyl, carboxylic ester, chlorodiphenyl, carbamate and alkoxysilane groups, at the para-position of the phenyl ring were synthesized via condensation reaction with H2O2 in the presence of N, N’-dicyclohexylcarbodiimide (DCC). The structures of BPO derivatives were characterized by 1H NMR spectra. The polymerization of vinylidene fluoride (VDF) and chlorotrifluoroethylene (CTFE), initialized by the functionalized BPOs, was successfully conducted in acetonitrile. The 1H NMR, 19F NMR spectra and GPC results revealed intact functional groups and 1.9 of functionality degree (two ends). The utility of the telechelic copolymers has been demonstrated by forming cross-linked fluoropolymer networks and by synthesizing well-defined block copolymers through atom transfer radical polymerization (ATRP), polyaddition reaction or polycondensation reaction. Block copolymers, comprised of conducting and ferroelectric blocks, were synthesized to determine the impact of block structures on the dielectric properties. The octaaniline oligomer utilized was synthesized via a modified literature method and has a comparable conductivity to polyaniline. Subsequently, a series of dumbbell-shaped triblock copolymers with octamer anilines at both ends were prepared. The polymer weights characterized by GPC were 59, 45, 32, 17 and 13 kg/mol, resulting in the octaaniline concentrations in the block copolymers of 4.8%, 6.5%, 10%, 14.8% and 18.7% respectively. The block structure was further confirmed by 1H NMR, Uv-Vis and FTIR analysis. An Agilent multifrequency LCR meter was utilized to determine the impact of octaanline concentration, doping reagents, and film preparation methods on the dielectric properties of the block polymers. It was found that both the permittivity and dielectric loss increased with increasing the octaaniline concentration of. By changing the sequence of doping and casting the films, different percolation thresholds of conduction were achieved.