Work

Polymer-Grafted WS 2 Nanocomposites: from Edge-Site Passivation to Melt-Stable Fused Granular Fabrication

Year: 2026

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide Layered transition metal dichalcogenides (TMDs) are widely regarded as chemically inert nanofillers in polymer composites. Here, we demonstrate that this assumption fails under melt-processing conditions. We show that pristine WS 2 nanopowders act as heterogeneous catalysts for polyester chain scission during melt extrusion, inducing a catastrophic, 10-fold reduction in molecular weight, severe loss of melt viscosity, printing failure, and brittle mechanical behavior at filler loadings as low as 0.2 wt %. To suppress this unexpected catalytic activity, we develop an edge- and defect-selective functionalization strategy for WS 2 based on covalent carboxylation and hydroxylation, followed by surface-initiated ring-opening polymerization of ε-caprolactone. Spectroscopic and microscopic analyses (XPS, XRD, HAADF-STEM, and EELS) demonstrate that polymer grafting is confined to edge and defect sites, while preserving the multilayer 2H-WS 2 lattice. When incorporated into a polycaprolactone (PCL) matrix and processed by large-format fused granular fabrication, polymer-grafted WS 2 nanostructures exhibit stable melt rheology, excellent printability, and substantial mechanical reinforcement, with Young’s modulus and tensile strength increases up to 45% and 65%, respectively, without loss of ductility. Crucially, polymer grafting effectively passivates catalytically active WS 2 edge and defect sites, preventing melt-induced polymer degradation. These findings provide direct experimental evidence that exposed edge sites in layered nanomaterials can actively catalyze polymer degradation under melt-processing conditions and establish edge-site passivation as a general design principle to mitigate chemically driven polymer degradation in polyester-based systems during melt processing, with the magnitude of the effect depending on the chemical susceptibility of the host polymer.

Source: ACS Nano

DOI: 10.1021/acsnano.5c22326

Authors: Mirko Maturi, Alberto Sanz de Leon, Luisa M. Valencia, Sergio I. Molina, Miriam Herrera

Institutions: Universidad de Cádiz, Instituto de Ciencia de Materiales de Sevilla

Language: English

Topic: Polymer Nanocomposites and Properties

Subfield: Polymers and Plastics

Field: Materials Science

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,500

Funders: Universidad de Cádiz, Junta de Andalucía