POS7-0503
Accelerating Interfacial Chain Dynamics in Polylactic-acid Nanocomposites via Densely Grafted Cellulose Nanocrystals: Translating to Macroscopic Property Breakthroughs
Topic
S7. Innovations in Polymeric Composites: From Design and Processing to Industrial Applications
When and Where
Sep 30, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Heesuk KIM
Jinhye BAE
Presenter(s)
Hyojin Jung (Seoul National University)
Co-Author(s)
Abstract
Polylactic acid (PLA) is a prominent biodegradable polymer whose performance can be significantly enhanced by incorporating cellulose nanocrystals (CNCs) as functional fillers. However, the intrinsic chemical incompatibility between the hydrophobic PLA and hydrophilic CNC surfaces often leads to filler aggregation, limiting their macroscopic performance. To overcome this fundamental bottleneck, we precisely designed PLA-grafted CNC (gCNC) to tailor interfacial structures and polymer dynamics.
This study systematically compared the distinct effects of physical adsorption vs. chemical grafting at the interface by using a model system and a commercial high-MW matrix. Small-angle X-ray scattering and rheological analyses revealed that the densely grafted layer of gCNC acts as a shell, inducing uniform dispersion and NP-induced fluidification that reduces melt viscosity even below that of neat PLA. Furthermore, broadband dielectric spectroscopy and quasi-elastic neutron scattering demonstrated that anchored grafted chains adopt a unique stretched conformation, expanding free volume and consistently accelerating segmental dynamics across ns and ps timescales. Crucially, this dynamic acceleration and microstructure directly translated into macroscopic property breakthroughs. Tensile testing showed that the dynamic gCNC interface successfully overcomes the conventional stiffness-toughness trade-off by providing an effective energy dissipation mechanism. Simultaneously, the dynamically relaxed interfacial structure facilitated enzymatic infiltration pathways, remarkably accelerating the overall biodegradability. Ultimately, this work establishes a multi-scale correlation extending from nanoscale interfacial dynamics to macroscopic multi-functionality, offering a new physical paradigm for the design of high-performance sustainable polymers.
This study systematically compared the distinct effects of physical adsorption vs. chemical grafting at the interface by using a model system and a commercial high-MW matrix. Small-angle X-ray scattering and rheological analyses revealed that the densely grafted layer of gCNC acts as a shell, inducing uniform dispersion and NP-induced fluidification that reduces melt viscosity even below that of neat PLA. Furthermore, broadband dielectric spectroscopy and quasi-elastic neutron scattering demonstrated that anchored grafted chains adopt a unique stretched conformation, expanding free volume and consistently accelerating segmental dynamics across ns and ps timescales. Crucially, this dynamic acceleration and microstructure directly translated into macroscopic property breakthroughs. Tensile testing showed that the dynamic gCNC interface successfully overcomes the conventional stiffness-toughness trade-off by providing an effective energy dissipation mechanism. Simultaneously, the dynamically relaxed interfacial structure facilitated enzymatic infiltration pathways, remarkably accelerating the overall biodegradability. Ultimately, this work establishes a multi-scale correlation extending from nanoscale interfacial dynamics to macroscopic multi-functionality, offering a new physical paradigm for the design of high-performance sustainable polymers.
