Thermoreversible Diels-Alder Cross-Linking of BHMF-Based Polyesters: Synthesis, Characterization and Rheology.

2,5-Bis(hydroxymethyl)furan (BHMF)-based polyesters are an interesting new class of biobased and potentially biodegradable furanic polymers. However, their thermal properties are currently insufficient, making them unsuitable for potential applications as commodity plastics. To improve this, several polyesters were synthesized using an enzymatic bulk polymerization process with the monomers BHMF and aliphatic dimethyl esters of varying spacer lengths.

Rapid Microwave-Assisted Chemical Recycling of Poly(-Phenylene Terephthalamide).

Back-to-monomer chemical recycling of polymers is crucial in achieving a circular plastics economy. Herein, we report the rapid microwave-assisted depolymerization of poly(-phenylene terephthalamide) (PPTA), also known as Twaron or Kevlar. The alkaline hydrolysis of PPTA was conducted in a microwave reactor at temperatures ranging from 240 to 260 °C with reaction times of 1-15 min.

Improving the Long-Term Mechanical Properties of Thermoplastic Short Natural Fiber Compounds by Using Alternative Matrices.

Wood plastic composites (WPCs) offer a means to reduce the carbon footprint by incorporating natural fibers to enhance the mechanical properties. However, there is limited information on the mechanical properties of these materials under hostile conditions. This study evaluated composites of polypropylene (PP), polystyrene (PS), and polylactic acid (PLA) processed via extrusion and injection molding.

Borax Cross-Linked Acrylamide-Grafted Starch Self-Healing Hydrogels.

The biocompatibility and renewability of starch-based hydrogels have made them popular for applications across various sectors. Their tendency to incur damage after repeated use limits their effectiveness in practical applications. Improving the mechanical properties and self-healing of hydrogels simultaneously remains a challenge.

Effects of the Amylose/Amylopectin Ratio of Starch on Borax-Crosslinked Hydrogels.

Herein, we simultaneously prepared borax-crosslinked starch-based hydrogels with enhanced mechanical properties and self-healing ability via a simple one-pot method. The focus of this work is to study the effects of the amylose/amylopectin ratio of starch on the grafting reactions and the performance of the resulting borax-crosslinked hydrogels. An increase in the amylose/ amylopectin ratio increased the gel fraction and grafting ratio but decreased the swelling ratio and pore diameter.

Durable and High-Performance Triboelectric Nanogenerator Based on an Inorganic Triboelectric Pair of Diamond-Like-Carbon and Glass.

The long-term durability of triboelectric nanogenerators (TENGs) remains a main challenge for practical applications because of inevitable material abrasion and wear, especially for sliding TENGs. Herein, an inorganic triboelectric pair composed of diamond-like carbon (DLC) and glass with excellent durability and triboelectric output for sliding-mode TENGs is proposed. This triboelectric pair possesses a low coefficient of friction and little abrasion and accordingly excellent durability (>500 000 cycles).

Innovative Approaches for Manufacturing Epoxy-Modified Wood and Cellulose Fiber Composites: A Comparison between Injection Molding and 3D Printing.

The current study focused on improving the properties of polylactic acid (PLA) for wider application in load-bearing scenarios. Various methods were explored to optimize the interaction between PLA and natural fibers, particularly wood fibers (WFs). Alkalized and epoxy-impregnated WFs were evaluated against untreated WFs and cellulose fibers in both injection molding (IM) and fused deposition modeling (FDM).

Ring-opening polymerization of emulsion-templated deep eutectic system monomer for macroporous polyesters with controlled degradability.

Biodegradable polyesters with interconnected macroporosity, such as poly(l-lactide) (PLLA) and poly(ε-caprolactone) (PCL), have gained significant importance in the fields of tissue engineering and separation. This study introduces functional macroinitiators, specifically polycaprolactone triol (PCL) and polyethylene glycol (PEG), both OH-terminated, in the solventless ring-opening polymerization (ROP) of a liquid deep eutectic system monomer (DESm) composed of LLA and CL at a 30 : 70 molar ratio, respectively. The macroinitiators selectively initiate the organocatalyzed ROP of LLA in the DESm during the first polymerization stage, thereby modifying the PLLA architecture.

Enzymatic Synthesis of Copolyesters with the Heteroaromatic Diol 3,4-Bis(hydroxymethyl)furan and Isomeric Dimethyl Furandicarboxylate Substitutions.

Polyesters from furandicarboxylic acid derivatives, i.e., dimethyl 2,5-furandicarboxylate (2,5-DMFDCA) and 2,4-DMFDCA, show interesting properties among bio-based polymers.

Effect of Polyelectrolyte Charge Density on the Linear Viscoelastic Behavior and Processing of Complex Coacervate Adhesives.

It is well-known that the phase behavior and physicochemical and adhesive properties of complex coacervates are readily tuneable with the salt concentration of the medium. For toxicity reasons, however, the maximum applicable salt concentration in biomedical applications is typically low. Consequently, other strategies must be implemented in order to optimize the properties of the resulting complex coacervates.

Lipoic acid-based vitrimer-like elastomer.

Dynamic covalent networks (DCNs) are materials that feature reversible bond formation and breaking, allowing for self-healing and recyclability. To speed up the bond exchange, significant amounts of catalyst are used, which creates safety concerns. To tackle this issue, we report the synthesis of a lipoic acid-based vitrimer-like elastomer (LAVE) by combining (i) ring-opening polymerization (ROP) of lactones, (ii) lipoic acid modification of polylactones, and (iii) UV crosslinking.

Thiol-Ene Click Cross-linking of Starch Oleate Films for Enhanced Properties.

Biobased films were synthesized from starch oleate (DS = 2.2) cross-linked with polyethylene glycol with = 2000 and 1000 g · mol, and ethylene glycol, all of which were esterified with either lipoic acid (LA) or 3-mercaptopropionic acid (MPA). Cross-linking was achieved through a UV-initiated thiol-ene click, and confirmed by Fourier transform infrared spectroscopy and rheometry.

One-Pot Synthesis of Strong Anionic/Charge-Neutral Amphiphilic Block Copolymers.

Despite the ever more versatile polymerization techniques that are becoming available, the synthesis of macromolecules with tailored functionalities can remain a lengthy endeavor. This becomes more conspicuous when the implementation of incompatible chemistries (i.e.

Starch ester film properties: The role of the casting temperature and starch its molecular weight and amylose content.

Oleic acid and 10-undecenoic acid were used to esterify corn, tapioca, potato and a waxy potato starch, with a maximum degree of substitution of 2.4 and 1.9 respectively.

Synthesis and Properties of Fully Biobased Crosslinked Starch Oleate Films.

Starch oleate (degree of substitution = 2.2) films were cast and crosslinked in the presence of air using UV curing (UVC) or heat curing (HC). A commercial photoinitiator (CPI, Irgacure 184) and a natural photoinitiator (NPI, a mixture of biobased 3-hydroxyflavone and n-phenylglycine) were used for UVC.

Biobased Photopolymer Resin for 3D Printing Containing Dynamic Imine Bonds for Fast Reprocessability.

Acrylic photopolymer resins are widely used in stereolithographic 3D printing. However, the growing demand for such thermosetting resins is weighing on global issues such as waste management and fossil fuel consumption. Therefore, there is an increasing demand for reactive components that are biobased and enable recyclability of the resulting thermoset products.

Biobased 2,5-Bis(hydroxymethyl)furan as a Versatile Building Block for Sustainable Polymeric Materials.

Furanic polymers, currently mainly represented by polyethylene 2,5-furandicarboxylate (PEF), also known as polyethylene furanoate, have a fantastic potential to replace fossil-based polymers: for example, polyethylene terephthalate (PET). While 2,5-furandicarboxylic acid (FDCA), a precursor of PEF, and its derived polymers have been studied extensively, 2,5-bis(hydroxymethyl)furan (BHMF) has received relatively little attention so far. Similarly to FDCA, BHMF is a biobased platform chemical derived from renewable sources such as sugars.

New insights in polydopamine formation via surface adsorption.

Polydopamine is a biomimetic self-adherent polymer, which can be easily deposited on a wide variety of materials. Despite the rapidly increasing interest in polydopamine-based coatings, the polymerization mechanism and the key intermediate species formed during the deposition process are still controversial. Herein, we report a systematic investigation of polydopamine formation on halloysite nanotubes; the negative charge and high surface area of halloysite nanotubes favour the capture of intermediates that are involved in polydopamine formation and decelerate the kinetics of the process, to unravel the various polymerization steps.

Scalable and Degradable Dextrin-Based Elastomers for Wearable Touch Sensing.

Elastomer-based wearables can improve people's lives; however, frictional wear caused by manipulation may pose significant concerns regarding their durability and sustainability. To address the aforementioned issue, a new class of advanced scalable supersoft elastic transparent material (ASSETm) is reported, which offers a unique combination of scalability (20 g scale), stretchability (up to 235%), and enzymatic degradability (up to 65% in 30 days). The key feature of our design is to render native dextrin hydrophobic, which turns it into a macroinitiator for bulk ring-opening polymerization.

Strong Anionic/Charge-Neutral Block Copolymers from Cu(0)-Mediated Reversible Deactivation Radical Polymerization.

Despite recent developments in controlled polymerization techniques, the straightforward synthesis of block copolymers that feature both strong anionic and charge-neutral segments remains a difficult endeavor. In particular, solubility issues may arise during the direct synthesis of strong amphiphiles and typical postpolymerization deprotection often requires harsh conditions. To overcome these challenges, we employed Cu(0)-mediated reversible deactivation radical polymerization (Cu(0)-RDRP) on a hydrophobic isobutoxy-protected 3-sulfopropyl acrylate.

A more efficient synthesis and properties of saturated and unsaturated starch esters.

This work presents a series of starch esters synthesized via 1,5,7-triazabicyclo[4.4.0]-dec-5-ene (TBD) catalyzed transesterifications in dimethyl sulfoxide (DMSO).

Influence of different ester side groups in polymers on the vapor phase infiltration with trimethyl aluminum.

The vapor phase infiltration (VPI) process of trimethyl aluminum (TMA) into poly(4-acetoxystyrene) (POAcSt), poly(nonyl methacrylate) (PNMA) and poly(-butyl methacrylate) (PtBMA) is reported. Depth-profiling X-ray photoelectron spectroscopy (XPS) measurements are used for the first time for VPI based hybrid materials to determine the aluminum content over the polymer film thickness. An understanding of the reaction mechanism on the interaction of TMA infiltrating into the different polymers was obtained through infrared (IR) spectroscopy supported by density functional theory (DFT) studies.

Enzymatic Synthesis of Muconic Acid-Based Polymers: Trans, Trans-Dimethyl Muconate and Trans, β-Dimethyl Hydromuconate.

The vast majority of commodity polymers are acquired from petrochemical feedstock, and these resources will plausibly be depleted within the next 100 years. Therefore, the utilization of carbon-neutral renewable resources for the production of polymers is crucial in modern green chemistry. Herein, we report an eco-friendly strategy that uses enzyme catalysis to design biobased unsaturated (co)polyesters from muconic acid derivatives.