Effective Reinforcement of Melamine-functionalized WS 2 Nanosheets in Epoxy Nanocomposites at Low Loading via Enhanced I
- PDF / 4,942,427 Bytes
- 11 Pages / 595 x 842 pts (A4) Page_size
- 39 Downloads / 185 Views
Article www.springer.com/13233 pISSN 1598-5032 eISSN 2092-7673
Effective Reinforcement of Melamine-functionalized WS2 Nanosheets in Epoxy Nanocomposites at Low Loading via Enhanced Interfacial Interaction Shahina Riaz Soo-Jin Park*
Department of Chemistry, Inha University, 100 Inharo, Incheon 22212, Korea Received April 14, 2020 / Revised July 16, 2020 / Accepted July 19, 2020
Abstract: We present a two-dimensional tungsten disulfide (WS2)-based material as a reinforcement additive to produce thermally stable, mechanically strong, and light-weight epoxy (EP) composites. An aqueous melamine solution was used to exfoliate the bulk WS2 into nanosheets while simultaneously functionalizing them to obtain melamine-functionalized WS2 (N-WS2) nanosheets. These non-covalently functionalized N-WS2 nanosheets were used as toughening agents for epoxy composites. The contents of the N-WS2 nanosheets were maintained at below 1 wt%. The effect of functionalization on the interfacial properties of EP composites was investigated in terms of the interfacial interactions between the EP and the nanosheets. The results demonstrated that the surface free energy of EP composites increased significantly after the incorporation of N-WS2 nanosheets into the EP matrix and further increased with the increased loading of N-WS2 nanosheets up to a maximal value of 54.38 mJ·m-2 for the composite containing 0.18 wt% N-WS2 nanosheets, suggesting a stronger interfacial interaction between the EP and N-WS2 nanosheets. A gradual decrease in the surface free energy of the EP composites was observed at higher loadings, which might be attributed to the aggregation of N-WS2 nanosheets within the matrix or excessive bonding of the sheets with one another rather than with the EP matrix due to their larger Van der Waals forces and their large surface area. The mechanical properties of the EP composites were analyzed and demonstrated 55%, 101%, 44%, and 15% improvements in the fracture toughness, fracture energy, flexural strength, and flexural modulus, respectively, for the composite containing 0.18 wt% N-WS2 nanosheets. Moreover, the composites displayed increased glass transition temperatures and better thermal stabilities. Keywords: EP composites, N-WS2 nanosheets, fracture toughness, low weight fractions, surface free energy.
1. Introduction Epoxy (EP)-based composite materials have gained significant attention in many technological fields due to their exceptional mechanical strength, excellent electrical insulation, good heat and chemical resistance, and low shrinkage.1-5 Due to rapid developments in the energy and automobile industries over the past few decades, the demand has increased for higher mechanical strength EP-based composite materials for use in high-performance applications.6-8 Several approaches to enhancing the mechanical strength of EP composites were adopted in the past, including Acknowledgments: This research was supported by Korea Evaluation institute of Industrial Technology (KEIT) through the Carbon Cluster Construction project
Data Loading...
