Cellulose-graft-polystyrene bottle-brush copolymers by homogeneous RAFT polymerization of soluble cellulose macro-CTAs and 'CTA-shuttled' R-group approach
| Autor: | Heike Herbert, Markus Biesalski, Marcus W. Ott, Michael Graf |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
chemistry.chemical_classification
Materials science Molar mass Polymers and Plastics musculoskeletal neural and ocular physiology Organic Chemistry 02 engineering and technology Polymer 010402 general chemistry 021001 nanoscience & nanotechnology Grafting 01 natural sciences 0104 chemical sciences chemistry.chemical_compound chemistry Polymerization Polymer chemistry Materials Chemistry Copolymer Reversible addition−fragmentation chain-transfer polymerization cardiovascular diseases Polystyrene Cellulose 0210 nano-technology psychological phenomena and processes |
| Zdroj: | Polymer. 98:505-515 |
| ISSN: | 0032-3861 |
| DOI: | 10.1016/j.polymer.2016.05.006 |
| Popis: | In this work we introduce well-defined cellulose-graft-copolymers prepared from CTA-functionalized cellulose and an CTA-shuttled R-approach in solution. Micro-crystalline cellulose was transferred into a cellulose-CTA in a three-step approach with degrees of substitution for CTA, DS(CTA), of about 0.2–0.6. Additional transfer of residual OH-groups with propionic ester groups resulted in cellulose-CTA molecules that were well-soluble in a large number of organic solvents. Model polymerizations using styrene monomer, AIBN as initiator and added free CTA produced well-defined cellulose-graft-PS copolymers. The molar mass of the macromolecules generated on the cellulose backbone were found to be similar as the molar mass of the polymers obtained from the CTA free in solution, which allowed a simple analysis of the graft copolymers. The molar mass of the cellulose-grafted PS could be well-controlled between less than 5000 g/mol to more than 40,000 g/mol by adjusting the reaction conversion through variation of the polymerization time. Analysis of the initiation efficiency showed that by using the CTA-shuttled approach for the generation of cellulose-graft-copolymers one can obtain very high grafting densities (relative amount of grafted chains on the cellulose backbone) as well as grafting ratios (relative mass gain due to grafting of the polymers onto the cellulose backbone). The presented results thus offer a number of possibilities for future design of functional cellulose-based bottle brush architectures. |
| Databáze: | OpenAIRE |
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