Synthesis, Structure, and Redox Properties of Nonsymmetric 6-Oxoverdazyls.

Nonsymmetric 6π-electron ("oxidized") 6-oxoverdazyls have been synthesized for the first time. After formal incorporation of a hydrogen atom, the corresponding 7π-electron neutral verdazyl radical is generated. The 7π radical can undergo a further electrochemically reversible reduction to an 8π anion.

Bioderived Thiol-Ene Emulsion Polymerization for Hybrid Latex Particles.

The thiol-ene emulsion polymerization of three dienes synthesized from bioderived compounds, and subsequent preparation of core-shell polymer latexes, is reported. Levoglucosan (LGA), levogucosenone (LGO) and isosorbide were first modified with 4-pentenoic acid to install polymerizable groups. These monomers were used along with a dithiol to prepare poly(thioether) particles via emulsion polymerization using potassium persulfate as initiator and sodium dodecyl sulfate as surfactant.

Synthesis and Characterization of Thiol-Ene Networks Derived from Levoglucosenone.

Levoglucosenone (LGO), a renewable compound obtained from cellulose biomass, has been utilized to prepare novel monomers bearing alkene functional groups. These monomer derivatives of LGO were subsequently cured via ultraviolet (UV)-initiated radical thiol-ene "click" chemistry with commercially available multifunctional thiols to obtain colourless, optically transparent cross-linked thermosets. The monomers prepared in this work are unique due to utilising the internal double bond of the LGO ring during polymerization as part of the cross-linked network.

Promoting Silk Fibroin Adhesion to Stainless Steel Surfaces by Interface Tailoring.

Bonding dissimilar materials has been a persistent challenge for decades. This paper presents a method to modify a stainless steel surface (316 L), routinely used in medical applications to enable the significant adhesion of a biopolymer (silk fibroin). The metallic surface was first covalently grafting with polyacrylamide, to enable a hydrogen bonding compatible surface.

Examining the Role of Aryldiazonium Salts in Surface Electroinitiated Polymerization.

Historically, the irreversible reduction of aryldiazonium salts has provided a reliable method to modify surfaces, demonstrating a catalogue of suitable diazonium salts for targeted applications. This work expands the knowledge of diazonium salt chemistry to participate in surface electroinitiated emulsion polymerization (SEEP). The influence of concentration, electronic effects, and steric hindrance/regiochemistry of the diazonium salt initiator on the production of polymeric films is examined.

α-Aminophosphonate Derivatives for Enhanced Flame Retardant Properties in Epoxy Resin.

This work demonstrates the introduction of various α-aminophosphonate compounds to an epoxy resin system, thereby improving flame retardance properties. The α-aminophosphonate scaffold allows for covalent incorporation (via the secondary amine) of the compounds into the polymer network. This work explores the synergistic effect of phosphorus and halogens (such as fluorine) to improve flame retardancy.

Insulating Composites Made from Sulfur, Canola Oil, and Wool*.

An insulating composite was made from the sustainable building blocks wool, sulfur, and canola oil. In the first stage of the synthesis, inverse vulcanization was used to make a polysulfide polymer from the canola oil triglyceride and sulfur. This polymerization benefits from complete atom economy.

Expanding the Scope of Surface Grafted Polymers Using Electroinitiated Polymerization.

The ability to rapidly modify the surface of materials is a powerful means of tailoring interfaces and interphases for a variety of applications. In this work, we demonstrate the extensive scope of an electrochemically mediated surface modification technique, able to install a range of surface grafted polymers of varying polarity and functionality. The irreversible reduction of aryldiazonium salts initiates polymer growth and provides a "priming layer" for the polymers to attach to, covalently anchoring them to the surface.

Using Polymerization to Increase Puncture Resistance and Induce Reversible Formability in Silk Membranes.

Silk fibroin is an excellent biopolymer for application in a variety of areas, such as textiles, medicine, composites and as a novel material for additive manufacturing. In this work, silk membranes were surface modified by polymerization of aqueous acrylic acid, initiated by the reduction of various aryldiazonium salts with vitamin C. Treatment times of 20 min gave membranes which possessed increased tensile strength, tensile modulus, and showed significant increased resistance to needle puncture (+131%), relative to 'untreated' standards.

Effect of Tow Size and Interface Interaction on Interfacial Shear Strength Determined by Iosipescu (V-Notch) Testing in Epoxy Resin.

Testing methodologies to accurately quantify interfacial shear strength (IFSS) are essential in order to understand fiber-matrix adhesion. While testing methods at a microscale (single filament fragmentation test-SFFT) and macroscale (Short Beam Shear-SBS) are wide spread, each have their own shortcomings. The Iosipescu (V-notch) tow test offers a mesoscale bridge between the microscale and macroscale whilst providing simple, accurate results with minimal time investment.