Abstracts

David Attenborough in Blue Planet II did what many polymer scientists in my field have been trying to do for years: Convince the public and government that the challenges of plastic waste are real and need to be fixed. But is this as simple as doing away with single use plastic? This talk will explore the complex nature of our plastic environment, the interdependency of plastics on our goals for lowering our carbon footprint and increasing our expected lifespan, while also showcasing our own work on how polymer chemistry has the opportunity to shape a new sustainable future by developing interdisciplinary solutions that work across the supply chain. Through our project “One Bin To Rule Them All”, we will explore systemic approaches to improving sustainable fates, from reuse to recycling (we work across enzymatic, chemical and mechanical recycling) and the opportunities and risks of new monomers for degradable polymers, and how the environmental sustainability can work in concert with economic and social sustainability. We will also discuss our work on qualifying and quantifying the recycled content in plastic packaging, helping to rebuild trust in recycling and plastics across the policy landscape.

Green material solutions are instrumental in our collective pursuit of a more sustainable society. The bio-based origin is central; however, if this does not connect to green chemistry, we will not contribute towards a more benign material economy. This presentation focuses on our recent work in applying the principles of green chemistry toward the development of circular and non-circular polymeric and biocomposite materials. Great emphasis is on connecting the expected lifetime of the materials with the targeted circularity. In other words, we keep the final application in mind while simultaneously dissecting the challenge to specific chemical problems related to organic, polymer, or material science. Examples of this entail developing new acrylates for in-situ polymerization of transparent and smart biocomposites, chemically recyclable and fully biobased epoxy biocomposites,  development of modular polymerization strategies towards degradable polymer systems, as well as exploring new functionalization concepts for cellulose, such as oxime-ligation towards the reversible covalent functionalization, or chemical modification of cellulose in fully bio-based ionic liquids. Central in this work is to capitalize on the complexity of biopolymers and inherent chemical features of platform molecules and explore concepts such as chemical accessibility, reactivity, and orthogonal functionality.

Society depends on polymeric materials now more than at any other time in history. Although synthetic polymers are indispensable in a diverse array of applications, ranging from commodity packaging and structural materials to technologically complex biomedical and electronic devices, their synthesis and disposal pose important environmental challenges. The focus of our research is the development of sustainable routes to polymers that have reduced environmental impact using catalysis. This lecture will focus on our research to: 1) mechanically recycle polymers; 2) develop chemically recyclable polymers; and 3) transition from fossil fuels to renewable resources for polymer synthesis, as well as the development of polymeric materials that exhibit lower post-use impact on the environment. 

Most of the industrially used polymers are immiscible and incompatible and do not form a homogeneous mixture. Stabilizing these immiscible mixed plastics could increase their lifespan and enable previously unrecoverable mixed plastic wastes to be reprocessed and reused. Here, we study how reversible dynamics covalent bonds can reactivate mixed plastic "dead"; chains into compatibilized multiblock copolymers. We develop a phenomenological bead-spring model and carry out large-scale molecular dynamics (MD) simulations of an incompatible homopolymer blend. These simulations show a clear transition from an immiscible blend to a progressively more miscible one via dynamic crosslinking when thermally activated. The creation of a "living"; gMBCPs, is found to be the underpinning driver for the increased miscibility. They enhance the local density of microphase-separated domains and compatibilize the interfaces of the blend. We further perform non-equilibrium MD simulations and show that the reversible dynamic crosslinking improves the mechanical properties, and thus the reusability of the blend. The work provides fundamental insights into the thermomechanical recycling of polymers.

Friction plays a vital role in locomotion, serving both as a challenge to be overcome and a force to be harnessed.  It also causes wear and the worn-out particles cause pollution. Our experiments show that sub millimeter sized particles worn out due to wear follow a power law distribution.  This would mean a significantly higher presence of sub-micron particles than previously assumed under the exponential distribution model. Considering the slow settling rate of smaller particles, our study underscores the possibility of a substantial underestimation of airborne tire wear particles, raising important questions about their environmental impact.