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| Content Provider | Royal Society of Chemistry (RSC) |
|---|---|
| Author | Shimizu, Toshihiro Kobayashi, Yoko Sato, Moriyuki Yamaguchi, Isao |
| Copyright Year | 2010 |
| Abstract | Novel hyperbranched (HB) polyesters with interior 4,7-diphenyl-2,1,3-benzothiadiazole (DBT) units were prepared by melt polycondensation of a dimethyl ester derivative of DBT (BMBT) (A2 monomer) with 2-hydroxymethyl-2-methyl-1,3-propanediol (HMP) (B3 monomer) at various mole ratios (A2/B3) via an A2 + B3 approach. The liquid crystalline (LC) and optical properties were investigated. FT-IR and 1H NMR spectroscopies revealed that the HB polymers have good solubility in chloroform, and can be synthesized without gelation during the polymerization with a degree of branching (DB) of 36–94%. The branched structures of HB polymers are dependent on the feed mole ratio. The HB polymer prepared from a mole ratio of A2/B3 = 1/3 had the highest number average molecular weight (Mn) and a more linear structure than the other HB polymers (A2/B3 = 3/1, 2/1, 3/1 and 1/2), which had the lowest DB values. DSC measurements, polarizing microscopy observations and X-ray analyses suggested that the HB polymer (A2/B3 = 1/3) forms the smectic A phase, whereas the others formed the smectic C phase. UV-vis and photoluminescent (PL) spectra in the solutions and in films indicated that the HB polymers show maximum absorbances and yellow-light emission attributable to the DBT unit. The PL spectra of HB polymers in film showed another broad peak, which was likely to be due to interchain interactions or aggregations, at longer wavelengths. Relative quantum yields (Φ) of the HB polymers in the chloroform solutions were lower than those of HB polymers comprising the 2-phenylbenzothiazole unit. Polarized absorption and fluorescent spectra revealed that the HB polymers have poor orientation properties and the luminescent properties are independent of the orientation structures of HB polymers. |
| Starting Page | 891 |
| Ending Page | 898 |
| Page Count | 8 |
| File Format | HTM / HTML PDF |
| ISSN | 17599954 |
| Volume Number | 1 |
| Issue Number | 6 |
| Journal | Polymer Chemistry |
| DOI | 10.1039/b9py00358d |
| Language | English |
| Publisher | Royal Society of Chemistry |
| Access Restriction | Open |
| Subject Keyword | Chloroform Liquid crystal Photoluminescence Polymerization Polymer Broad Peak Fourier-transform infrared spectroscopy X-ray crystallography Ester Quantum Microscopy DSC DBT Condensation polymer Nuclear magnetic resonance Molar mass distribution Monomer 1,3-Propanediol Melanocytic nevus |
| Content Type | Text |
| Resource Type | Article |
| Subject | Organic Chemistry Biochemistry Bioengineering Biomedical Engineering Polymers and Plastics |
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