A new synthetic route to symmetrical 2,6-diarylphenols (1) has been developed. This route has, as its key step, a phase transfer catalyzed double nucleophilic displacement reaction of 1,3-dibromopropane by a 1,3-diarylpropanone leading to a 2,6-diarylcyclohexanone. The latter compound is then converted to 1 by catalytic dehydrogenation. Phenols prepared in this way were 2,6-bis(p-tolyl)phenol (1a), 2,6-bis(p-methoxyphenyl)phenol (1b) and 2,6-bis(p-biphenylyl)phenol (1c). All intermediates and products were characterized by elemental analysis, IR, ('1)H NMR and ('13)C NMR spectroscopy. These phenols were then polymerized oxidatively to give the corresponding polyoxyphenylenes which were characterized by IR, ('1)H NMR and ('13)C NMR spectroscopy. Molecular weights and molecular weight distributions were derived from gel permeation chromatography. Glass transition temperatures, crystallization temperatures and crystalline melting points were determined by differential scanning calorimetry. Thermal stability was monitored by thermal gravimetric analysis. The desired goal of a high molecular weight soluble polymer which crystallizes thermally but which has a lower crystalline melting point than poly(oxy-2,6-diphenyl-1,4-phenylene) (PDPP) (480(DEGREES)C) was achieved with poly{oxy-2,6-bis(p-tolyl)-1,4-phenylene} (PDTP), which melted at 321(DEGREES)C. The homopolymer from 1b (PDAP) could not be prepared with high molecular weight due to extensive crystallization and insolubilization during polymerization. Attempted polymerization of 1c produced only dimer. The three monomers were each copolymerized randomly with 2,6-diphenylphenol. All copolymers were completely amorphous as determined by differential scanning calorimetry. The blending behavior of PDTP and PDAP with PDPP was investigated by differential scanning calorimetry. Both blends produced clear films. In each case, however, the homopolymers crystallized and melted independently.
| Identifer | oai:union.ndltd.org:UMASS/oai:scholarworks.umass.edu:dissertations-5799 |
| Date | 01 January 1981 |
| Creators | DANA, DAVID ERIC |
| Publisher | ScholarWorks@UMass Amherst |
| Source Sets | University of Massachusetts, Amherst |
| Language | English |
| Detected Language | English |
| Type | text |
| Source | Doctoral Dissertations Available from Proquest |
Page generated in 0.0022 seconds