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Nitroxide-mediated homopolymerization and statistical copolymerization of commercially available methacrylates derived from sustainable feedstocks (isobornyl methacrylate (IBOMA) and a mixture of methacrylic esters with an average alkyl side chain length of 13 units (termed C13MA)) was conducted in organic solvent (toluene) and in dispersed aqueous media using an oil-soluble unimolecular initiator (Dispolreg 007) without any controlling comonomers in a controlled manner. IBOMA homopolymerization in emulsion at 83−100 °C revealed the optimal polymerization temperature of 90 °C giving relatively narrow molecular weight distributions (1.46 < dispersities (Đ) < 1.58) and conversion up to 83% in a relatively short time (2 h). IBOMA/C13MA statistical copolymerizations yielded copolymers with tunable glass transition temperature (T g ) prepared in emulsion (−52 °C < T g < 123 °C) and in organic solvent (−40 °C < T g < 169 °C). Resins made in emulsion at 90 °C proceeded up to 92.7% conversion with monomodal molecular weight distributions (M̅ n up to 68,000 g mol −1 and Đ = 1.62−1.72) and were colloidally stable (24% solids and final average particle sizes of 270−481 nm). Furthermore, chain end fidelity was verified by chain extensions with IBOMA and C13MA monomers in both emulsion and organic solvent. These results constitute a readily scalable route to make polymers via nitroxide-mediated polymerization with controlled architecture using biobased feedstocks without the hazards of bulk or homogeneous organic solvent polymerization.

Nitroxide‐mediated polymerization (NMP) of isobornyl methacrylate (IBOMA) and tridecyl methacrylate (TDMA), derived from sustainable feedstocks, with a low fraction of acrylonitrile (AN) co‐monomer were conducted with unimolecular initiator BlocBuilder‐MA™ (BB) and the succinimidyl ester‐functionalized form, NHS‐BB. IBOMA and TDMA‐rich compositions were both polymerized at 100 °C in a controlled manner (i.e., linear increase in number average molecular weight [Mn] with conversion up to ∼40% and low dispersity, Đ < 1.5). SG1‐terminated poly(IBOMA‐stat‐AN) macroinitiator was then cleanly chain‐extended with poly(TDMA‐stat‐AN) and the diblock copolymers exhibited two distinct glass transition temperatures (Tgs), indicative of microphase separation. IBOMA/TDMA/AN terpolymers with different IBOMA/TDMA molar ratios were also synthesized where terpolymers with higher IBOMA content had higher apparent rate constants and higher Tgs. Moreover, chain growth was linear up to conversions of ∼60% and all Đs were 1.51 to 1.64. Finally, 2‐hydroxyethyl methacrylate (HEMA) was incorporated into the IBOMA/TDMA/AN system, resulting in statistical quadripolymers. The quadripolymer Tg decreased with increasing TDMA content and Mn ranged from 12 to 15.4 kg mol−1 and the Đ were 1.39 to 1.54, suggesting the successful incorporation of sustainably sourced monomers into quadripolymers with a broad range of tunable Tgs via NMP with additional functionalities from HEMA. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2422–2436

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Crustacean shell waste is one of the most important chitin sources for commercial use due to its low price and high availability. The extraction of chitin from this residue relies on two removal steps: one for proteins and another one for minerals. Herein, we report a "solvent-free", one-pot process relying on mechanochemistry and aging to convert crustacean shells into chitin with high yields and low ash content. The extraction was performed on European Green Crabs, one of the world's most damaging invasive species, thus converting a serious environmental threat into a biomaterial opportunity. Successful chitin isolation of Green Crabs was achieved by milling of solid acids (i.e., citric, ascorbic, malic, succinic, and salicylic acid) for 10 to 30 min, while a combination of milling and aging was necessary for aqueous acids (i.e., hydrochloric and acetic acid). Milling, aging times, and shell to acid ratios were optimized, while the process could be scaled to 200 g of shell starting materials. This method required limited chemical and energy inputs, which were quantified by sustainability metrics. The process reported is a more sustainable approach for chitin production over the current industrial methods and has the potential to be extended to other chitin sources (e.g., lobster, shrimp, and insects).

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