TY - JOUR
T1 - Softwood Lignin-Based Methacrylate Polymers with Tunable Thermal and Viscoelastic Properties
AU - Holmberg, Angela L.
AU - Nguyen, Ngoc A.
AU - Karavolias, Michael G.
AU - Reno, Kaleigh H.
AU - Wool, Richard P.
AU - Epps, Thomas H.
N1 - Funding Information:
The authors from the University of Delaware (UD) Department of Chemical and Biomolecular Engineering acknowledge NSF Grant CHE-1507010 and AFOSR-PECASE Grant FA9550-09-1-0706 for partial financial support. The authors from the UD Center for Composite Materials acknowledge a SERDP WP-1758 through the Cooperative Agreement W911NF-06-2-001 for partial financial support. N.A.N. acknowledges the UD Department of Materials Science and Engineering and NIST Award 70NANB10H256 through the UD Center for Neutron Science for financial support. The UD NMR facility used for this project was supported by the Delaware COBRE program with a grant from the National Institute of General Medical Sciences−NIGMS (1 P30GM110758-01) from the National Institutes of Health. The authors thank Scott R. Horton and Prof. Michael T. Klein for helpful discussions; Prof. Joseph F. Stanzione, III, for providing some monomer; Prof. Michael E. Mackay for use of the rheometer; and the UD Advanced Materials Characterization Lab for use of the DSC and TGA instruments.
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/3/8
Y1 - 2016/3/8
N2 - Softwood (guaiacylic) lignin-based methacrylate polymers (LBMPs) that exhibit excellent glass transition temperatures (Tg's), desirable thermal stabilities (greater than 100°C above Tg), and intermediate shear-flow resistances, in comparison to polystyrene and poly(methyl methacrylate), are reported herein. Different R-groups (p-position hydrogen, methyl, ethyl, and formyl groups) in otherwise homologous LBMPs impart distinct characteristics to the flow behavior and thermal properties of these bio-based polymers, which permit the investigation of unique structure-property relationships. More specifically, the zero-shear viscosities (η0's) for the LBMPs span nearly 2 orders of magnitude as the R-group is varied, while the characteristic degradation temperatures differ more modestly (by ≈50°C over the same series of polymers), and the Tg's exhibit minimal, yet application relevant, variations between ≈110 and ≈130°C. These property differences were probed independent of tacticity, molecular weight, and dispersity effects due to the nature of the well-controlled macromolecules generated via reversible addition-fragmentation chain-transfer polymerization. Furthermore, heteropolymers prepared from mixtures of the lignin-based monomers have composition-dependent Tg's and component-dependent thermal degradation temperatures, thermolysis rates, and η0's. The multicomponent materials demonstrate the enhanced tunability inherent in LBMPs. Altogether, this versatile library of softwood lignin-based monomers, and the unique structure-property relationships intrinsic to the resulting polymers, provides a unique platform for building potentially low-cost, high-performance, and bio-based viscoelastic materials attractive for thermoplastic elastomer and binder applications.
AB - Softwood (guaiacylic) lignin-based methacrylate polymers (LBMPs) that exhibit excellent glass transition temperatures (Tg's), desirable thermal stabilities (greater than 100°C above Tg), and intermediate shear-flow resistances, in comparison to polystyrene and poly(methyl methacrylate), are reported herein. Different R-groups (p-position hydrogen, methyl, ethyl, and formyl groups) in otherwise homologous LBMPs impart distinct characteristics to the flow behavior and thermal properties of these bio-based polymers, which permit the investigation of unique structure-property relationships. More specifically, the zero-shear viscosities (η0's) for the LBMPs span nearly 2 orders of magnitude as the R-group is varied, while the characteristic degradation temperatures differ more modestly (by ≈50°C over the same series of polymers), and the Tg's exhibit minimal, yet application relevant, variations between ≈110 and ≈130°C. These property differences were probed independent of tacticity, molecular weight, and dispersity effects due to the nature of the well-controlled macromolecules generated via reversible addition-fragmentation chain-transfer polymerization. Furthermore, heteropolymers prepared from mixtures of the lignin-based monomers have composition-dependent Tg's and component-dependent thermal degradation temperatures, thermolysis rates, and η0's. The multicomponent materials demonstrate the enhanced tunability inherent in LBMPs. Altogether, this versatile library of softwood lignin-based monomers, and the unique structure-property relationships intrinsic to the resulting polymers, provides a unique platform for building potentially low-cost, high-performance, and bio-based viscoelastic materials attractive for thermoplastic elastomer and binder applications.
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U2 - 10.1021/acs.macromol.5b02316
DO - 10.1021/acs.macromol.5b02316
M3 - Article
AN - SCOPUS:84961147637
SN - 0024-9297
VL - 49
SP - 1286
EP - 1295
JO - Macromolecules
JF - Macromolecules
IS - 4
ER -