Softwood (guaiacylic) lignin-based methacrylate polymers (LBMPs) that exhibit excellent glass transition temperatures (T g 's), desirable thermal stabilities (greater than 100 °C above T g ), 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 (η 0 '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 T g '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 T g 's and component-dependent thermal degradation temperatures, thermolysis rates, and η 0 '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.

High separations costs reduce the practicality of polymers sourced from renewable bio-oils, motivating economical multicomponent bio-oil polymerizations. Thus, this paper investigates polymerization behavior of model bio-oil components and their mixtures.

We report the synthesis and melt self-assembly behaviors of densely grafted, core−shell bottlebrush (csBB) polymers derived from covalently linking narrow dispersity, symmetric composition ABA-type triblock polymers through their chain midpoints. Derived from sequential ring-opening polymerizations of εdecalactone and rac-lactide initiated from 5-norbornene-2-exo,3-exo-dimethanol, poly(lactide-block-ε-decalactone-block-lactide) macromonomers (M n = 9.2−17.8 kg/mol; Đ = 1.19−1.25) were enchained by living ring-opening metathesis polymerization (ROMP) into csBBs with backbone degrees of polymerization N bb = 8−43. Temperature-dependent small-angle X-ray scattering (SAXS) studies indicate that the critical triblock arm degree of polymerization (N arm ) required for melt segregation decreases with increasing N bb , leading to reductions in the accessible ordered lamellar microdomain (d) spacings. We derive a phenomenological relationship between the critical triblock arm segregation strength at the order−disorder transition (χN arm ) ODT and N bb to enable the future design of microphase separated core−shell bottlebrushes, which self-assemble at sub-10 nm length scales for nanolithography and nanotemplating applications.