| 1. |
- Bonjour, Olivier, et al.
(author)
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Lignin-Inspired Polymers with High Glass Transition Temperature and Solvent Resistance from 4-Hydroxybenzonitrile, Vanillonitrile, and Syringonitrile Methacrylates
- 2021
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In: ACS Sustainable Chemistry & Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 9:50, s. 16874-16880
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Journal article (peer-reviewed)abstract
- We here report on the synthesis and polymerization of nitrile-containing methacrylate monomers, prepared via straightforward nitrilation of the corresponding lignin-inspired aldehyde. The polymethacrylates reached exceptionally high glass transition temperatures (Tg values), i.e., 150, 164, and 238 °C for the 4-hydroxybenzonitrile, vanillonitrile, and syringonitrile derivatives, respectively, and were thermally stable up to above 300 °C. Copolymerizations of the nitrile monomers with styrene and methyl methacrylate, respectively, gave potentially melt processable materials with tunable Tg values and enhanced solvent resistance. The use of lignin-derived nitrile-containing monomers represents an efficient strategy toward well-defined biobased high Tg polymer materials.
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| 3. |
- Laanesoo, Siim, et al.
(author)
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Combining isosorbide and lignin-related benzoic acids for high-Tg polymethacrylates
- 2024
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In: European Polymer Journal. - 0014-3057. ; 202
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Journal article (peer-reviewed)abstract
- The insertion of rigid aliphatic or aromatic building blocks in polymer structures is an efficient synthetic strategy towards high-Tg polymer materials. In the present work, we have functionalized isosorbide 5-methacrylate with various aromatic lignin-inspired esters to yield a series of isosorbide-2-aryl carboxylate-5-methacrylate monomers (ArIMAs) as single regioisomers. The selection of phenyl carboxylate side groups included benzoate, p-cyanobenzoate, meta/para-methoxybenzoates, and different vanillic acid esters. This afforded a range of seven bio-based monomers with different size, polarity, and substitutions. Polymerizations were carried out by conventional free radical initiation to obtain the corresponding high molecular-weight poly(aryl carboxylate isosorbide methacrylate)s (PArIMAs). The polymerizations were evaluated in different solvents, including toluene, EtOAc, γ-valerolactone, 2-MeTHF, and DMSO to identify the most suitable conditions. The polymers exhibited high glass transition temperatures (Tgs) in a broad range, from 80 to 168 °C, and were thermally stable up to 268 °C. Furthermore, dynamic rheology experiments indicated that the polymers were sufficiently stable for melt processing. The availability of the building blocks combined with the high stability of the polymers make these materials attractive for use as high-performance plastics and coatings.
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| 4. |
- Laanesoo, Siim, et al.
(author)
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Poly(alkanoyl isosorbide methacrylate)s: from amorphous to semi-crystalline and liquid crystalline biobased materials
- 2021
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In: Biomacromolecules. - : American Chemical Society (ACS). - 1526-4602 .- 1525-7797. ; 22:2, s. 640-648
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Journal article (peer-reviewed)abstract
- We have prepared a series of twelve D-isosorbide-2-alkanoate-5-methacrylate monomers as single regioisomers with different pendant linear C2 to C20 alkanoyl chains by using biocatalytic and chemical acylations. By conventional radical polymerization, these monomers afforded high-molecular weight biobased poly(alkanoyl isosorbide methacrylate)s (PAIMAs). Samples with C2-C12 alkanoyl chains were amorphous with glass transition temperatures from 107 to 54 °C, while C14-C20 chains gave semi-crystalline materials with melting points up to 59 °C. Moreover, PAIMAs with C13-C20 chains formed liquid crystalline mesophases with transition temperatures up to 93 °C. The mesophases were studied by polarized optical microscopy, and rheology showed stepwise changes of the viscosity at the transition temperature. Unexpectedly, a PAIMA prepared from a regioisomeric monomer (C18) showed semi-crystallinity but no liquid crystallinity. Consequently, the properties of the PAIMAs were readily tunable by controlling the phase structure and transitions through the alkanoyl chain length and the regiochemistry to form fully amorphous, semi-crystalline or semi-/liquid crystalline materials.
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| 8. |
- Sedrik, Rauno, et al.
(author)
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Chemically Recyclable Poly(β-thioether ester)s Based on Rigid Spirocyclic Ketal Diols Derived from Citric Acid
- 2022
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In: Biomacromolecules. - : American Chemical Society (ACS). - 1526-4602 .- 1525-7797. ; 23:6, s. 2685-2696
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Journal article (peer-reviewed)abstract
- Incorporating rigid cyclic acetal and ketal units into polymer structures is an important strategy towards high-performance materials from renewable resources. In the present work, citric acid, a widely used platform chemical derived from biomass, has been efficiently converted into diand tricyclic diketones. Ketalization with glycerol or trimethylolpropane afforded rigid spirodiols, which were obtained as complex mixtures of isomers. After a comprehensive NMR analysis, the spirodiols were converted into the respective di(meth)acrylates and utilized in thiol-ene polymerizations in combination with different dithiols. The resulting poly(β-thioether ester ketal)s were thermally stable up to 300 °C and showed glass transition temperatures in a range from -7 to 40 °C, depending on monomer composition. The polymers were stable in aqueous acids and bases, but in a mixture of 1 M aq. HCl and acetone, the ketal functional groups were cleanly hydrolyzed, opening the pathway for potential chemical recycling of these materials. We envision that these novel bioderived spirodiols have a great potential to become valuable and versatile bio-based building blocks for several different kinds of polymer materials.
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