Lignin-Sourced Aromatics for Biodegradable Flexible Copolyesters Mimicking Poly(Butylene Adipate-co- Terephthalate).

Two new diacid monomers containing either fluorene or sulfone moieties polymerize via step-growth polymerization in the presence of their diol counterparts or alkyl diols (ethylene glycol and 1,6-hexanediol), forming eight new cardo structure polyesters. The polymers exhibit high optical transparency in the thin-film form with refractive indices ranging from 1.56 to 1.69, tunable glass transition temperatures from ca. 40 to 116 °C with no melting temperature, and resistance to thermal degradation in a nitrogenous atmosphere, reaching 350-398 °C before observing 10% weight loss. Their molecular weights, M w , range from ca. 17 to 77 kDa, with an average polydispersity, Đ, of 1.5, and average purified yields of 82%. The polymers absorb light primarily in the UV region from ca. 228 to 320 nm with no absorption from 320 to 800 nm. A critical finding is that some of the fluorene and sulfone monomers induce negative bioactivity and even cell death in T47D-KBLuc cells, a breast cancer cell line, at high concentrations. This report details the project inspiration, monomer synthesis, polymerization steps, structural confirmation, material characterization, and the impact of the new monomer's estrogenic and antiestrogenic bioactivity.

The development of robust methods for the synthesis of chemically recyclable polymers with tunable properties is necessary for the design of next-generation materials. Polyoxazolidinones (POxa), polymers with five-membered urethanes in their backbones, are an attractive target because they are strongly polar and have high thermal stability, but existing step-growth syntheses limit molar masses and methods to chemically recycle POxa to monomer are rare. Herein, we report the synthesis of high molar mass POxa via ring-opening metathesis polymerization of oxazolidinone-fused cyclooctenes. These novel polymers show <5% mass loss up to 382-411 °C and have tunable glass transition temperatures (14-48 °C) controlled by the side chain structure. We demonstrate facile chemical recycling to monomer and repolymerization despite moderately high monomer ring-strain energies, which we hypothesize are facilitated by the conformational restriction introduced by the fused oxazolidinone ring. This method represents the first chain growth synthesis of POxa and provides a versatile platform for the study and application of this emerging subclass of polyurethanes.

3D printing of polyurethane/nanocellulose shape memory composites with tunable glass transition temperature

A class of sustainable and renewable cellulose–rosin copolymers were prepared by immobilizing rosin-derived polymer chains on the backbone of ethyl cellulose (EC) by “grafting from” atom transfer radical polymerization (ATRP). Four different rosin based polymers derived from dehydroabietic acid (DA), one of the major resin acids in natural rosin, were attached to 2-bromoisobutyryl-functionalized EC. Meanwhile, DA-grafted EC was prepared by the simple esterification reaction between DA and EC. Kinetic studies showed that the polymerization of all monomers was controlled. These grafted copolymers adopt a worm-like or rod-like structure in tetrahydrofuran, verified by light scattering experiments. These copolymers have a tunable glass transition temperature and higher thermal stability in contrast to EC. Surface morphology by AFM analysis indicated good film-forming property when rosin polymers were grafted from EC. Additionally, the introduction of DA and rosin polymers remarkably enhanced the hydrophobicity of EC. The static contact angles of all these modified copolymers are above 90°. XPS analysis revealed that the surface of these rosin-modified EC copolymers was dominated by a hydrocarbon-rich rosin moiety. The UV absorption of modified EC composites is indicative of their potential application in UV-absorbent coating materials.

Photopolymerization coupled with mask projection microstereolithography successfully generated various 3D printed phosphonium polymerized ionic liquids (PILs) with low UV light intensity requirements and high digital resolution. Varying phosphonium monomer concentration, diacrylate cross-linking comonomer, and display images enabled precise 3D design and polymeric properties. The resulting cross-linked phosphonium PIL objects exhibited a synergy of high thermal stability, tunable glass transition temperature, optical clarity, and ion conductivity, which are collectively well-suited for emerging electro-active membrane technologies. Ion conductivity measurements on printed objects revealed a systematic progression in conductivity with ionic liquid monomer content, and thermal properties and solvent extraction demonstrated the formation of a polymerized ionic liquid network, with gel fractions exceeding 95%.

As hydrogen-bond donors and acceptors, N,N′-disubstituted sulfamides have been used in a range of applications from medicinal chemistry to anion-binding catalysis. However, compared to ureas or thioureas, the utilization of this unique moiety remains marginal, in part because of a lack of general synthetic methods to access unsymmetrical sulfamides. Specifically, polysulfamides are a virtually unknown type of polymer despite their potential utility in non-covalent dynamic networks, an intense area of research in materials science. We report herein a practical and efficient process to prepare unsymmetrical sulfamides via Sulfur(vi)-Fluoride Exchange (SuFEx) click chemistry. This process was then applied to synthesize polysulfamides. Thermal analysis showed that this family of polymers possess high thermal stability and tunable glass transition temperatures. Finally, hydrolysis studies indicated that aromatic polysulfamides could be recycled back to their constituting monomers at the end of their life cycle.

Highly transparent and photopatternable spirobifluorene-based polythioethers with high refractive indices via thiol-ene click chemistry

Environmental impacts and mitigation potentials of CO2-based biodegradable plastic based on life cycle assessment – A case study of poly(propylene carbonate)

Epoxy‐based shape memory polymers (ESMPs) are important types of thermoset shape memory polymers due to their unique thermomechanical properties, which have great potential in applications ranging from smart actuators to deformable structures. The long‐term storage stability is important for ESMPs, especially when pursuing the same batch of materials for alternatives. Stable storage of ESMP preplomyers in the long term and taking it out for curing when needed are of great benefit to engineering applications which highly require the same batch of materials for high production efficiency, such as in deployable space structures, semiconductor, and electronic packaging. However, this important storage stability of ESMP has not been studied so far. Herein, a series of ESMPs with tunable glass transition temperatures (Tgs) ranging from 100 to 170 °C is prepared. The effect of long‐term storage at low temperatures on rheological, thermal, thermomechanical, mechanical, and shape memory properties is systematically investigated. The ESMP after storage shows an improvement of crosslinking density, Tgs, and mechanical strength, while maintaining chemical structures and excellent shape memory properties. This feasible method of low‐temperature storage realizes overall long‐term stability and enhancement of strength in ESMPs, making it more promising for engineering applications.

Strong and ultrafast stimulus-healable lignin-based composite elastomers with excellent adhesion properties

Vanillin, as a promising aromatic aldehyde, possesses worthy structural and bioactive properties useful in the design of novel sustainable polymeric materials. Its versatility and structural similarity to terephthalic acid (TPA) can lead to materials with properties similar to conventional poly(ethylene terephthalate) (PET). In this perspective, a symmetrical dimethylated dialkoxydivanillic diester monomer (DEMV) derived from vanillin was synthesized via a direct-coupling method. Then, a series of poly(ether-ester)s were synthesized via melt-polymerization incorporating mixtures of phenyl/phenyloxy diols (with hydroxyl side-chains in the 1,2-, 1,3- and 1,4-positions) and a cyclic diol, 1,4-cyclohexanedimethanol (CHDM). The polymers obtained had high molecular weights (Mw = 5.3–7.9 × 104 g.mol−1) and polydispersity index (Đ) values of 1.54–2.88. Thermal analysis showed the polymers are semi-crystalline materials with melting temperatures of 204–240 °C, and tunable glass transition temperatures (Tg) of 98–120 °C. Their 5% decomposition temperature (Td,5%) varied from 430–315 °C, which endows the polymers with a broad processing window, owing to their rigid phenyl rings and trans-CHDM groups. These poly(ether-ester)s displayed remarkable impact strength and satisfactory gas barrier properties, due to the insertion of the cyclic alkyl chain moieties. Ultimately, the synergistic influence of the ester and ether bonds provided better control over the behavior and mechanism of in vitro degradation under passive and enzymatic incubation for 90 days. Regarding the morphology, scanning electron microscopy (SEM) imaging confirmed considerable surface degradation in the polymer matrices of both polymer series, with weight losses reaching up to 35% in enzymatic degradation, which demonstrates the significant influence of ether bonds for biodegradation.

Mexylaminotriazine derivatives form molecular glasses with outstanding glass-forming ability (GFA), high resistance to crystallization (glass kinetic stability, GS), and a glass transition temperature (Tg) above room temperature that can be conveniently modulated by selection of the headgroup and ancillary groups. A common feature of all these compounds is their secondary amino linkers, suggesting that they play a critical role in their GFA and GS for reasons that remain unclear because they can simultaneously form hydrogen (H) bonds and lead to a high interconversion energy barrier between different rotamers. To investigate independently and better control the influence of H bonding capability and rotational energy barrier on Tg, GFA and GS, a library of twelve analogous molecules was synthesized with different combinations of NH, NMe and O linkers. Differential scanning calorimetry (DSC) revealed that these compounds form, with a single exception, kinetically stable glasses with Tg values spanning a very broad range from -25 to 94 °C. While variable temperature infrared spectroscopy combined to chemometrics reveals that, on average, around 60% of the NH groups are still H-bonded as high as 40 °C above Tg, critical cooling rates obtained by DSC clearly show that molecules without H-bond donating linkers also present an outstanding GFA, meaning that H bonding plays a dominant role in controlling Tg but is not required to prevent crystallization. It is a high interconversion energy barrier, provoking a distribution of rotamers, that most efficiently promotes both GFA and resistance to crystallization. These new insights pave the way to more efficient glass engineering by extending the possible range of accessible Tg, allowing in particular the preparation of homologous glass-formers with high GS at ambient temperature in either the viscous or vitreous state.

Recent advances in synthetic methods and monomer design have given access to precision carbohydrate polymers that extend beyond native polysaccharides. In this article, we present the synthesis of a class of chemically recyclable ester-linked pseudo-polysaccharides via the living anionic ring-opening polymerization of glucurono-1,6-lactones. Notably, the pseudo-polysaccharides exhibited defined chain-end groups, well-controlled molecular weights, and narrow molecular weight distributions, all hallmarks of living polymerization. Furthermore, we demonstrate that our approach is modular, as evidenced by tunable glass transition temperatures (Tg) and the ability to produce both amorphous and semicrystalline polymers by adjusting the monomer side chain structure. Lastly, we showcased the complete catalytic chemical recycling of these pseudo-polysaccharides back to the monomers. The flexibility of the polymerization and the recyclability of these pseudo-polysaccharides promote a sustainable circular economy while offering the potential to access polysaccharide-like materials with tunable thermal and mechanical properties.

Access to self-assembled nanoparticles has become increasingly vital for the development of next generation adjuvants for the delivery of nucleic acid therapeutics. However, the block ratio of amphiphilic block copolymers plays a significant role in achieving the desired architectures and in some cases coformulation of two different block copolymers is needed. Herein, we introduce an elegant approach to self-assembled stomatocytes and cubosomes through coformulation of PEG and poly(2-oxazoline) (POx) based lactide diblock copolymers. A series of well-defined POx macroinitiators and their block copolymers with D,L-lactide (PDLLA) has been synthesized and achieved narrow polydispersity indices at high monomer conversions. Thermal analysis of block copolymers indicated tunable glass transition temperatures (Tg) ranging from 33 °C to 56 °C. Other critical factors influencing the structure of the nanoparticle included the ratio of POx-PDLLA and PEG-PDLLA blocks as well as the hydrophobicity of the POx block. Moreover, DLS and cryo-TEM analysis revealed the formation of diverse nanostructures, namely stomatocytes, pseudo-vesicles, and possibly cubosomes. This versatile platform allows for precise control over nanoparticle shapes by adjusting block lengths and coformulation ratios. This highlights the potential of using coformulations in biomedical applications, enabling the rational design of advanced nanomaterials with tailored functionalities for specific targets.

Micro‐structured shape memory polymer (SMP) surfaces are indispensable in various applications. Epoxy polymer emerged as an ideal candidate for SMP surfaces due to its low curing shrinkage and superior thermo‐mechanical properties. In this study, we develop a UV curable epoxy system with tunable glass transition temperature and superior shape memory performance. The glass transition temperatures can widely range from 49 to 164°C by simply tuning the ratio of two comonomers. All samples possess excellent shape fixity, shape recovery ratios, and cycling stability. The synergy of the moldable liquid epoxy precursors and the spatiotemporal UV light allows shape memory epoxy with both surface microstructures and complex macro‐geometries. We anticipate this UV curable epoxy will expand the scopes of surface shape memory applications.