Effect of Methoxy Substituent Position on Thermal Properties and Solvent Resistance of Lignin-Inspired Poly(dimethoxyphenyl methacrylate)s

Abstract

The macromolecular properties, including the glass transition temperature (T g ) and solvent resistance, of lignin-inspired poly(dimethoxyphenyl methacrylate)s were controlled by varying the position of the dimethoxy substituents in the constituent monomers. For the four dimethoxyphenyl methacrylate isomers investigated, with substituents at different locations on the phenyl ring (i.e., 3,5-; 2,3-; 2,4-; and 2,6-), the T g 's of the resulting polymers spanned a wide range from less than 100 °C to greater than 200 °C. Rotational freedom and segmental interactions were responsible for the varying T g 's. The polymers were thermally stable in air up to ∼300 °C, providing a suitable thermal processing window. The poly(dimethoxyphenol methacrylate) homopolymers also exhibited remarkably different solvent resistances to organic solvents, including tetrahydrofuran and chloroform. Furthermore, by copolymerizing various dimethoxyphenyl methacrylate isomers, the T g and solvent resistance of the resulting macromolecules could be tuned independently to gain enhanced control over materials design. The ability to manipulate properties through isomer composition in this lignin-inspired system may facilitate usage in applications such as components in coatings, thermoplastics, thermoplastic elastomers, and other materials.

From Tree to Tape: Direct Synthesis of Pressure Sensitive Adhesives from Depolymerized Raw Lignocellulosic Biomass

“…The T g ’s of P4pGA (56 °C) and P4pGMA (80 °C) with one methoxy group at the ortho position were lower than those of P4pSA and P4pSMA, as the existence of two ortho methoxy groups constrained rotation of the pendant groups and raised the T g ’s of the dimethoxy-based materials. 18 A copolymer of 4pSMA and 4pGMA also was synthesized to demonstrate the feasibility of making polymers from the original biomass mixture, without fractionation into individual components. The monomer ratio of 4pSMA/4pGMA (0.60/0.40) and the segment content in the polymer (0.58/0.42, as determined via 1 H NMR spectroscopy) were consistent, suggesting a random incorporation of each substituent in the polymer backbone.…”

“…Poly(4pSA) and poly(4pGA) (see Figure S3 for 1 H NMR spectra) were synthesized by reversible addition–fragmentation chain-transfer (RAFT) polymerization, using a procedure described in the literature. 18 The initiator, 2,2′-azobis(isobutyronitrile) (AIBN, Sigma-Aldrich, 98%), was recrystallized twice from methanol prior to use. The chain-transfer agent (CTA), 3,5-bis(2-dodecyl-thiocarbonothioylthio-1-oxopropoxy)benzoic acid (BTCBA, Sigma-Aldrich, 98%), was used as received.…”

Preparation of Renewable Epoxy-Amine Resins With Tunable Thermo-Mechanical Properties, Wettability and Degradation Abilities From Lignocellulose- and Plant Oils-Derived Components

“…Lignans and lignin-derived chemicals that can be obtained through pyrolysis (Celikbag et al, 2017; Barde et al, 2018) or controlled depolymerization (Pandey and Kim, 2011; Shuai et al, 2016) are the most used biomass-derived chemical platforms for the design of bio-based BPA-substitutes, for the preparation of sustainable thermosets with high thermo-mechanical properties. Indeed, the aromatic moieties present in these bio-based chemicals confer rigidity to the resulting polymers (Wang et al, 2017; Feghali et al, 2018). For example, there have been many reports on epoxy resins from eugenol (Wan et al, 2016), vanillin (Fache et al, 2015a,b; Hernandez et al, 2016; Mauck et al, 2017; Nicastro et al, 2018; Savonnet et al, 2018; Zhao et al, 2018), ferulic and sinapic acids (Maiorana et al, 2016; Janvier et al, 2017; Ménard et al, 2017), guaiacols (Maiorana et al, 2015), and creosol (Meylemans et al, 2011) with promising performances capable of competing with current DGEBA-based materials.…”

Lignin-Inspired Polymers with High Glass Transition Temperature and Solvent Resistance from 4-Hydroxybenzonitrile, Vanillonitrile, and Syringonitrile Methacrylates

“… 25 These polymethacrylates, as well as similar ones based on phenol, syringol, and syringaldehyde, respectively, have been produced and investigated for various coating applications. 26 , 27 Lignin-derived building blocks, such as eugenol, 28 have also been employed to produce densely cross-linked thermosets with high T g values.…”