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.