Reprocessable Networks from Vegetable Oils, Salts, and Food Acids: A Green Polymer Outreach Demonstration for Middle School Students.

Massive amounts of mismanaged plastic waste have led to growing concerns about their adverse impacts on the environment, ecosystem, and human health. Enabling efficient plastic recycling is a key component for developing a sustainable future, which requires cohesive efforts in technology innovations, public awareness, and workforce development. Particularly, outreach activities to inform the broader community about current efforts to fabricate sustainable polymeric materials can play a central role in inspiring future generations while also improving their knowledge, viewpoints, and behaviors to address plastic waste challenges. Herein, this account demonstrates an effort to educate middle school students about a key emerging concept in polymer science for sustainable material development: reprocessable polymer networks. Background information is provided to the students about the need to transition from petroleum-based chemical feedstocks to their bioderived counterparts. We note that the materials used in this demonstration lesson are all produced from common household foods, with which students routinely interact in various applications, making them not only safe but also compelling for the middle school classroom.

Fluorescence Resonance Energy Transfer Measurements in Polymer Science: A Review.

Fluorescence resonance energy transfer (FRET) is a non-invasive characterization method for studying molecular structures and dynamics, providing high spatial resolution at nanometer scale. Over the past decades, FRET-based measurements are developed and widely implemented in synthetic polymer systems for understanding and detecting a variety of nanoscale phenomena, enabling significant advances in polymer science. In this review, the basic principles of fluorescence and FRET are briefly discussed. Several representative research areas are highlighted, where FRET spectroscopy and imaging can be employed to reveal polymer morphology and kinetics. These examples include understanding polymer micelle formation and stability, detecting guest molecule release from polymer host, characterizing supramolecular assembly, imaging composite interfaces, and determining polymer chain conformations and their diffusion kinetics. Finally, a perspective on the opportunities of FRET-based measurements is provided for further allowing their greater contributions in this exciting area.

Expedient Synthesis and Ring-Opening Metathesis Polymerization of Pyridinonorbornenes.

Pyridine-containing polymers are promising materials for a variety of applications from the capture of contaminants to the self-assembly of block copolymers. However, the innate Lewis basicity of the pyridine motif often hampers living polymerization catalyzed by transition-metal complexes. Herein, we report the expedient synthesis of pyridinonorbornene monomers via a [4+2] cycloaddition between 2,3-pyridynes and cyclopentadiene. Well-controlled ring-opening metathesis polymerization was enabled by careful structural design of the monomer. Polypyridinonorbornenes exhibited high Tg and Td, a promising feature for high-temperature applications. Investigation of the polymerization kinetics and of the reactivity of the chain ends shed light on the influence of nitrogen coordination on the chain-growth mechanism.