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Title: Enhancing the Mechanical Toughness of Epoxy-Resin Composites Using Natural Silk Reinforcements

Abstract

Strong and tough epoxy composites are developed using a less-studied fibre reinforcement, that of natural silk. Two common but structurally distinct silks from the domestic B. mori/Bm and the wild A. pernyi/Ap silkworms are selected in fabric forms. We show that the toughening effects on silk-epoxy composites or SFRPs are dependent on the silk species and the volume fraction of silk. Both silks enhance the room-temperature tensile and flexural mechanical properties of the composite, whereas the more resilient Ap silk shows a more pronounced toughening effect and a lower critical reinforcement volume for the brittle-ductile transition. Specifically, our 60 vol.% Ap-SFRP displays a three-fold elevation in tensile and flexural strength, as compared to pure epoxy resin, with an order of magnitude higher breaking energy via a distinct, ductile failure mode. Importantly, the 60 vol.% Ap-SFRP remains ductile with 7% flexural elongation at lower temperatures (-50 °C). Under impact, these SFRPs show significantly improved energy absorption, and the 60 vol.% Ap-SFRP has an impact strength some eight times that of pure epoxy resin. Lastly, the findings demonstrate both marked toughening and strengthening effects for epoxy composites from natural silk reinforcements, which presents opportunities for mechanically superior and "green" structural composites.

Authors:
 [1];  [1];  [1];  [2]; ORCiD logo [3]
  1. Beihang Univ., Beijing (China). Intl. Research Center for Advanced Structural and Biomaterials, School of Materials Science and Engineering
  2. Fudan Univ., Shanghai (China). State Key Lab. of Molecular Engineering of Polymers, Laboratory of Advanced Materials, Dept. of Macromolecular Science
  3. Beihang Univ., Beijing (China). Intl. Research Center for Advanced Structural and Biomaterials, School of Materials Science and Engineering; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1416937
Grant/Contract Number:  
AC02-05CH11231
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 7; Journal Issue: 1; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Composites; Mechanical properties

Citation Formats

Yang, Kang, Wu, Sujun, Guan, Juan, Shao, Zhengzhong, and Ritchie, Robert O. Enhancing the Mechanical Toughness of Epoxy-Resin Composites Using Natural Silk Reinforcements. United States: N. p., 2017. Web. doi:10.1038/s41598-017-11919-1.
Yang, Kang, Wu, Sujun, Guan, Juan, Shao, Zhengzhong, & Ritchie, Robert O. Enhancing the Mechanical Toughness of Epoxy-Resin Composites Using Natural Silk Reinforcements. United States. doi:10.1038/s41598-017-11919-1.
Yang, Kang, Wu, Sujun, Guan, Juan, Shao, Zhengzhong, and Ritchie, Robert O. Wed . "Enhancing the Mechanical Toughness of Epoxy-Resin Composites Using Natural Silk Reinforcements". United States. doi:10.1038/s41598-017-11919-1. https://www.osti.gov/servlets/purl/1416937.
@article{osti_1416937,
title = {Enhancing the Mechanical Toughness of Epoxy-Resin Composites Using Natural Silk Reinforcements},
author = {Yang, Kang and Wu, Sujun and Guan, Juan and Shao, Zhengzhong and Ritchie, Robert O.},
abstractNote = {Strong and tough epoxy composites are developed using a less-studied fibre reinforcement, that of natural silk. Two common but structurally distinct silks from the domestic B. mori/Bm and the wild A. pernyi/Ap silkworms are selected in fabric forms. We show that the toughening effects on silk-epoxy composites or SFRPs are dependent on the silk species and the volume fraction of silk. Both silks enhance the room-temperature tensile and flexural mechanical properties of the composite, whereas the more resilient Ap silk shows a more pronounced toughening effect and a lower critical reinforcement volume for the brittle-ductile transition. Specifically, our 60 vol.% Ap-SFRP displays a three-fold elevation in tensile and flexural strength, as compared to pure epoxy resin, with an order of magnitude higher breaking energy via a distinct, ductile failure mode. Importantly, the 60 vol.% Ap-SFRP remains ductile with 7% flexural elongation at lower temperatures (-50 °C). Under impact, these SFRPs show significantly improved energy absorption, and the 60 vol.% Ap-SFRP has an impact strength some eight times that of pure epoxy resin. Lastly, the findings demonstrate both marked toughening and strengthening effects for epoxy composites from natural silk reinforcements, which presents opportunities for mechanically superior and "green" structural composites.},
doi = {10.1038/s41598-017-11919-1},
journal = {Scientific Reports},
number = 1,
volume = 7,
place = {United States},
year = {Wed Sep 20 00:00:00 EDT 2017},
month = {Wed Sep 20 00:00:00 EDT 2017}
}

Journal Article:
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