A5056263965- Polymer composites and self-healing
- Advanced Materials and Mechanics
- Advanced Sensor and Energy Harvesting Materials
- Photochromic and Fluorescence Chemistry
- Electrospun Nanofibers in Biomedical Applications
- Additive Manufacturing and 3D Printing Technologies
- Natural Fiber Reinforced Composites
- Synthetic Organic Chemistry Methods
- Polymer Nanocomposites and Properties
- Advanced Cellulose Research Studies
- Advanced Polymer Synthesis and Characterization
- Conducting polymers and applications
- Tribology and Wear Analysis
- Thermal properties of materials
- Hydrogels: synthesis, properties, applications
- Modular Robots and Swarm Intelligence
- Mobile Learning in Education
- Carbon Nanotubes in Composites
- Soft Robotics and Applications
- Graphene research and applications
- Innovative Teaching and Learning Methods
- Carbon dioxide utilization in catalysis
- Flame retardant materials and properties
- Mechanical Engineering and Vibrations Research
- Reflective Practices in Education
Wright-Patterson Air Force Base
2021-2024
National Transportation Research Center
2024
Oak Ridge National Laboratory
2024
North Carolina State University
2017-2020
Hokkaido University
2019
North Central State College
2017
Vitrimers hold great promise as adaptive materials capable of shape reconfigurability, welding, and self-healing due to dynamic covalent reactions occurring above the vitrimer transition temperature (Tv). Previous literature reports Tv one value influenced mainly by chemistry; however, also significant inconsistencies when measuring or identifying trends. Herein, we present unique data interpretation methods analyze stress–relaxation elongational creep results allowing for excellent...
Epoxy materials are an indispensable class of polymers due to their excellent mechanical properties and high thermal resistance. However, traditional epoxy typically non-recyclable face issues with fatigue creep. To combat the issue recyclability, research interest is increasingly centered on vitrimer materials, which exhibit a dynamic covalent bond exchange reaction at temperatures allowing for self-healing, recycling, shape reprogramming. Herein, we discuss creep mechanics vitrimers;...
Abstract Incorporating dynamic bonds into polymers enables static thermosets to be transformed active materials, possessing the reprocessability of thermoplastics while maintaining bulk properties fully crosslinked networks. This new class termed covalent adaptable networks (CANs), has helped bridge gap between traditional and thermoplastics. Here, epoxy-based were synthesized by combining a diepoxide monomer with an oligosiloxane prepolymer containing aminopropyl groups, which crosslink...
Vitrimers, a subset of covalent adaptable networks (CANs), are class polymer material capable self-healing and shape reprocessing at temperatures above their topology freezing temperature (Tv), where dynamic bond exchange reactions dominate. In particular, epoxy vitrimers have the strength traditional low (T < Tg) coupled with processing capabilities thermoplastic high > Tv). addition, vitrimer composites attractive as potential industrial due to enhanced thermomechanical performance. While...
With sustainability at the forefront of material research, recyclable polymers, such as vitrimers, have garnered increasing attention since their introduction in 2011. In addition to a traditional glass-transition temperature (Tg), vitrimers second topology freezing (Tv) above which dynamic covalent bonds allow for rapid stress relaxation, self-healing, and shape reprogramming. Herein, we demonstrate memory, reconfigurability properties function experimental conditions, aiming toward...
Natural fiber composites offer an advantage in terms of weight saving for many automotive applications; however, natural lack properties to justify substitution synthetic composites. Hybridizing the by adding a fraction fibers is innovative approach provide balance between composite's performance and saving. In this study, coir (40 wt%)-reinforced polypropylene (PP) were hybridized substituting with glass (0-30 wt%). The prepared using novel wet-laid technique followed compression molding,...
The ability to change shape and control curvature in 3D structures starting from planar sheets can aid assembly add functionality an object. Herein, we convert of memory polymers (SMPs) into objects with controllable by dictating where the shrink. Ink patterned on surface sheet absorbs infrared (IR) light, resulting localized heating, material shrinks locally wherever temperature exceeds activation temperature, Ta. We introduce two different mechanisms for controlling within SMP sheets....
Vitrimers are an exciting class and new generation of polymer materials combining the strength a traditional thermoset with reprocessability thermoplastic polymer. However, key debate in literature has surrounded best method to identify vitrimer topology freezing temperature (Tv), above which dynamic covalent bond exchange reactions occur, allowing for self-healing, recycling, shape reconfigurability vitrimers. While common methods Tv include stress relaxation, creep, fluorescence, we herein...
Lignin-containing cellulose nanofibrils (LCNFs) are mainly produced commercially from treated wood pulp, which can decrease some of the carbon-negative benefits utilizing biomass feedstock. In this work, LCNFs prepared non-wood feedstocks, including agricultural residues such as hemp, wheat straw, and flax. These feedstocks allowed for preparation with a variety properties, tailored hydrophobicity. The their subsequent extensively characterized to determine roles that play on morphology...
Robotics and active materials have forged the path for grasping manipulating delicate objects of various geometries sizes. To date, majority soft robotic grippers used hydrogels or elastomers, which can repeatably grasp manipulate small objects. Many these achieve their grip (due to shape change) only in presence either solvent exposure external pneumatic pressure. Here, we demonstrate thermoplastic polystyrene sheets that actuate from flat into response light maintain upon removal light....
Vitrimers, an emerging class of polymer materials, are thermosets with dynamic covalent cross-linkers, allowing for topology rearrangement at elevated temperatures. However, vitrimers have several drawbacks, such as slow response times and often lack photothermal catalytic activity. Herein, we demonstrate that embedding functional nanofillers, i.e., hierarchically assembled plasmonic gold nanoparticles (AuNPs) on graphene nanoplatelets (GNPIs) into a vitrimer matrix, induces ultrafast...
ABSTRACT We report a simple method to strain, and thereby program, shape memory polymers by compressing planar thermoplastic sheets. This work is motivated the limited number of commercially available prestrained polymer sheets; current examples include: Shrinky Dinks, Eastman's Embrace, polyurethane shrink films. However, these commercial specimens limit sample thickness, composition, amount stored strain. show here that melt pressing can strain sheets over range thicknesses chemical...
Abstract Corrugations can dramatically change the effective mechanical properties of a thin sheet. Such alternating ridges and grooves are typically fabricated by processing. Herein, ability to trigger tune corrugations within ( ≈ 300 µ m thick) thermoplastic sheets rapidly seconds) using only light is reported. Patterns black ink on otherwise transparent, flimsy sheet preferentially adsorb external IR light, inducing localized heating underlying polymer. This causes shrinkage polymer,...