Center for Composite Materials - University of Delaware

Research Summary

Lignin-Based High-Performance Polymers and Block Copolymers

Authors: Joseph F. Stanzione, III (Ph.D.), Kaleigh H. Reno (Ph.D. Candidate), Joshua M. Sadler (Ph.D.), John J. La Scala (Ph.D.), Richard P. Wool (Ph.D. Advisor)

Aim

Schematic of life cycle of lignin-derived plastics. Schematic derived from Saito et al.(1)

Introduction

• High-performance polymers utilized in a wide-variety of industrial, commercial, and governmental applications are derived primarily from petrochemical feedstocks:
•• Epoxy, unsaturated polyester, and vinyl ester resins
•• Polycarbonates
•• Thermoplastic elastomers (SIS & SBS)
•• Styrene (reactive diluent, HAP, VOC, carcinogen)
• Cost and supply of these polymers are extremely volatile

Hypothesis: Lignin is a Viable, Renewable Feedstock for High-Performance Polymers(2)

• Copious paper and pulping industry waste
• 18 - 35 % content in wood
• ~ 20 gigatons generated annually
• Primarily burned for energy recovery
• High variability, intractable biopolymer
• High aromatic content
•• Aromaticity enhances polymer properties
• Extraction methods include:
•• Steam explosion cracking
•• Organosolv delignification
•• Alkaline or Kraft pulping

Research Method

• Lignin intractable in native state
• Strategic methods to selectively fractionate lignin being developed
• Strategic methods to chemically degrade lignin being developed
• Until technology advances further, lignin model compounds utilized to demonstrate lignin’s potential

Lignin Model Compounds (LMCs)(3-6)

• Representative mono-phenols
• Vanillin = main ingredient in extract of vanilla
• Recent studies show modest yields from lignin

Image: Representative lignin model compounds utilized in this research project.

Vinyl Ester 828 (VE828) Cured Resins with Modified LMCs as Reactive Diluents(7-8)

Image 1: Reaction of methacrylic anhydride with a lignin model compound to form a methacrylated lignin model compound monomer.
Image 2: Left: Glass transition temperature (Tg) of the cured VE828-based resins that contained either methacrylated eugenol (ME), styrene, phenyl methacrylate (PM), or methacrylated guaiacol (MG) as the reactive diluent and homopolymers of ME, styrene, PM, and MG as a function of reactive diluent content. Right: storage modulus (E’) at 25 °C of the cured VE828-based resins as a function of reactive diluent content.

• Performed DMA single cantilever-temperature ramp experiments
• Temperature of maximum loss modulus as Tg
• DSC utilized to determine Tgs of homopolymers
• Maximum standard deviations: Tg = ± 2.53 °C, E’ = ± 0.35 GPa

Vanillin-Based Thermoset(9)

Image 1: Two-step, one-pot synthesis scheme to produce a resin that contains a 1:1 mole ratio of methacrylated vanillin (desired mono-functional monomer of Reaction 1) and glycerol dimethacrylate (desired cross-linker of Reaction 2). The methacrylic acid produced in Reaction 1 is consumed in Reaction 2.

Image 2: Vanillin-based thermoset.

Green Attributes & Properties

Incorporating Vanillin Derivatives in Block Copolymers(11)

• Block Copolymers:
•• Applications include solar cells, battery membranes, coatings
•• Use living polymerization to control molecular weights and dispersities for controlling morphologies
•• Replace styrene as structural block with bio-based molecules
•• Work in Collaboration with the Epps’ group

Image: Schematic of potential block copolymer morphologies and the conversion of vanillin into potential useful monomers.

Others uses for Vanillin in Plastics

• Replace bisphenol-A (BPA)
• Polycondensation polymerizations
•• Polyesters
•• Polyurethanes
• High impact strength polymers like Kelvar

Methacrylated Bio-oil Thermoset(10)

Representative schematic of the synthesis of a methacrylated lignin-based bio-oil that can be utilized as a reactive diluent or as a thermosetting resin by itself.

References

(1) Saito, T., et al. Green Chemistry 2012, 14, 3295-3303.
(2) Genome Management Information System, Oak Ridge National Laboratory.
(3) Binder J.B., et al. Biomass Bioenergy 2009, 33, 1122 -1130.
(4) Petrocelli, F.P.; Klein, M.T. Ind. Eng. Chem. Prod. Res. Dev. 1985, 24, 635-641.
(5) Sergeev, A.G.; Hartwig, J.F. Science 2011, 332, 439-443.
(6) Meylemans, H. A., et al. ChemSusChem 2012, 5, 206-210.
(7) Stanzione III, J.F., et al. ChemSusChem 2012, 5, 1291-1297.
(8) Stanzione III, J.F., et al. Polymer In preparation.
(9) Stanzione III, J.F., et al. Green Chemistry 2012, 14, 2346-2352.
(10) Stanzione III, J.F. et al. ACS Sustainable Chem. Eng. 2013, 1, 419-426.
(11) Segalman, R.A. Mat. Sci. and Eng. 2005, 48, 191-226

Acknowledgements

This work is supported by the SERDP WP-1758 and the Army Research Laboratory through the Cooperative Agreement W911NF-06-2-0011.

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