| NSF Org: |
CMMI Division of Civil, Mechanical, and Manufacturing Innovation |
| Recipient: |
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| Initial Amendment Date: | November 25, 2013 |
| Latest Amendment Date: | January 23, 2015 |
| Award Number: | 1404627 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Tom Kuech
CMMI Division of Civil, Mechanical, and Manufacturing Innovation ENG Directorate for Engineering |
| Start Date: | September 1, 2013 |
| End Date: | August 31, 2017 (Estimated) |
| Total Intended Award Amount: | $362,771.00 |
| Total Awarded Amount to Date: | $375,316.00 |
| Funds Obligated to Date: |
FY 2014 = $5,000.00 FY 2015 = $7,545.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
926 DALNEY ST NW ATLANTA GA US 30318-6395 (404)894-4819 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
GA US 30332-0420 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): |
MATERIALS PROCESSING AND MANFG, Materials Eng. & Processing |
| Primary Program Source: |
01001415DB NSF RESEARCH & RELATED ACTIVIT 01001516DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.041 |
ABSTRACT
This grant provides funding for the study of the relationship between processing conditions and the healing and reprocessing of polymers and polymer composites containing dynamic covalent bonds. A significant feature of these polymers is that the backbone of the macromolecular chain can break and reconnect through bond exchange reactions. While such dynamic covalent reactions do not change the overall topology and properties of the polymer network, macroscopically they result in stress relaxation and material welding. The proposed work will examine the bond exchange reaction kinetics and welding kinetics and their dependence on processing conditions. Epoxy samples containing dynamic covalent bonds will be prepared in the lab and tested under different thermo-mechanical loading conditions to understand the effects of temperature on the bond exchange reaction kinetics. These samples will be broken then joined together under different thermo-mechanical loading conditions. Special dyes will be incorporated into polymer samples to facilitate monitoring the bond breaking and reforming process, as well as the migration of species due to bond exchange reactions. From these experiments, the relationships between bond exchange reaction kinetics, welding kinetics, and processing conditions will be established. The re-processibility of the dynamic covalent bond epoxy and its composites will also be investigated.
If successful, the results from this work will lead to the development of new ?green? epoxy and composites that can be reshaped and recycled. The primary goal of this research is to establish fundamental principles for bond exchange reaction kinetics and welding kinetics. These principles may include how processing parameters, such as temperature, hold time, applied pressure, and surface roughness, can affect reshaping, welding, and re-processibility of the epoxy. Determining these processing parameters will enable robust processing and recycling of the epoxy, reduction in processing cost, and improvement on product quality. The established principles can also be used for polymers containing other types of dynamic covalent bonds.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
The research objective of this project was to understand the relationship between processing conditions and the healing and reprocessing of epoxy with dynamic covalent bonds and to develop novel reprocessing and recycling methods for epoxy and their composites based on these fundamental understandings.
This project developed fundamental principles of bond exchange reaction kinetics and welding kinetics of epoxy with dynamic covalent bonds and established several innovative methods for healing, reprocessing, and recycling of epoxy and composites. First, this project established the principles of how processing parameters, such as temperature, applied pressure and time, surface roughness could affect welding, and reprocessing of epoxy. These principles led to the development of a new interface model that could predict the welding and reprocessing efficiency of epoxy. Second, based on the fundamental understandings, a new method that utilized epoxy powder to achieve recycling was developed. In this method, a wasted epoxy could be ground into powder that was later reformed into a new solid epoxy and this process could be repeated multiple times. Third, a novel method of using alcohol to recycle epoxy was developed. This method allowed both the epoxy and the alcohol to be collected for reuse. In addition, the alcohol could be used to glue two pieces of epoxy together, which offered a new method for epoxy part repair. Fourth, the alcohol based recycling approach was further developed for recycling carbon fiber composites where the carbon fibers could be reclaimed and reused. Finally, a new type of polymer that could be recycling by water at high temperature was developed.
The fundamental understandings and the new methods developed in this project are applicable for new repairing and recycling approaches for carbon fiber composites. These composites are used with increasing popularity in aerospace, automobile, and even some high-end consumer products, due to their advantage of high stiffness and light weight. However, broad applications of carbon fiber composites are limited by the high cost of carbon fibers and poor recyclability of the matrix polymer. The new methods developed in this project can be used to recycle industrial grade carbon fiber epoxy composites where the carbon fibers can be reclaimed without losing their mechanical properties. The reclaimed carbon fibers can be used as the filament for new composites. In such, the new methods have the potential to reduce the cost of carbon fibers and thus make carbon fiber available to a broader range of applications, such as in regular consumer products. This project also provided learning and training opportunities for students at both graduate and undergraduate levels. Undergraduate students from underrepresented group were involved in this project by participating research directly and thus were encouraged to pursue higher degrees or careers in STEM related field.
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Last Modified: 11/29/2017
Modified by: Hang (Jerry) Qi
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