Polycarbonates based on Carbon Dioxide

1. Functional Polycarbonates

Considering the influence of CO2 on the global climate and its formation on a giga-ton scale through combustion of fossil-fuels, aliphatic polycarbonates prepared from CO2 as a C1-component are highly interesting. Besides being resource-saving, such polycarbonates are biodegradable and biocompatible. With these properties, they are suitable for a broad range of applications like construction materials or biomedical purposes. Particularly, multifunctional polycarbonates (mf-PCs) are interesting as innovative materials. Besides different alkyl, vinyl,1 and propargyl groups,2 polycarbonates based on CO2 can be functionalized with ethers3, hydroxyl groups4 and many other groups when using functionalized epoxide monomers. These groups can be the starting point for several polymer modification reactions. Depending on the type of functional group, mf-PCs offer many possibilities, e.g. for graft polymerization1 or for cross-linking.


Figure 1: Synthesis scheme of multifunctional polycarbonates (left) and a simple reactor for the polymerization (right).

Currently we investigate novel synthesis routes, physical properties and modification possibilities for new multifunctional polycarbonates based on CO2.

2. Amphiphilic and Hyperbranched Polycarbonates

Besides aliphatic polycarbonates, amphiphilic structures5 and multifunctional architectures, such as hyperbranched and star-like polymers,6 offer numerous possibilities in the medical, pharmaceutical and materials science world. Branched polycarbonates are interesting for coatings since they offer a high number of functional groups. Also, nonionic amphiphilic polycarbonates are promising for academic research as well as for future industrial application, because of their biodegradability and biocompatibility.


Figure 2: Synthesis scheme of amphiphilic (left) and star-like (right) polycarbonates.

Currently our group targets novel synthesis routes, physical properties and modification possibilities of different polycarbonate architectures and their functionalization.

References

[1] "From CO2-Based Multifunctional Polycarbonates With a Controlled Number of Functional Groups to Graft Polymers" J. Geschwind, F. Wurm, H. Frey, Macromol. Chem. Phys. 2013, 214, 892–901. DOI: 10.1002/macp.201200608.
[2] Propargyl-functional aliphatic polycarbonate obtained from carbon dioxide and glycidyl propargyl ether" J. Hilf, H. Frey, Macromol. Rapid Commun. 2013, 34, 1395–1400. DOI: 10.1002/marc.201300425.
[3] "Stable, hydroxyl functional polycarbonates with glycerol side chains synthesized from CO(2) and isopropylidene(glyceryl glycidyl ether)" J. Geschwind, H. Frey, Macromol. Rapid Commun. 2013, 34, 150–155. DOI: 10.1002/marc.201200682.
[4] Poly(1,2-glycerol carbonate): A Fundamental Polymer Structure Synthesized from CO 2 and Glycidyl Ethers" J. Geschwind, H. Frey, Macromolecules 2013, 46, 3280–3287. DOI: 10.1021/ma400090m.
[5] "CO2-Based Non-ionic Surfactants: Solvent-Free Synthesis of Poly(ethylene glycol)- block -Poly(propylene carbonate) Block Copolymers" J. Hilf, P. Schulze, H. Frey, Macromol. Chem. Phys. 2013, 214, 2848–2855. DOI: 10.1002/macp.201300586.
[6] "Controlled synthesis of multi-arm star polyether-polycarbonate polyols based on propylene oxide and CO2" J. Hilf, P. Schulze, J. Seiwert, H. Frey, Macromol. Rapid Commun. 2014, 35, 198–203. DOI: 10.1002/marc.201300663.