Supertough PLA-Silane Nanohybrids by in Situ Condensation and

Dec 6, 2017 - Scheme 2. Chemical Structures of PLA and Alkoxysilanes Used in This Study. The tensile properties of neat PLA and its APTES hybrids are ...
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Supertough PLA-silane nanohybrids by in situ condensation and grafting Xiangtao Meng, Ngoc Nguyen, Halil Tekinalp, Edgar Lara-Curzio, and Soydan Ozcan ACS Sustainable Chem. Eng., Just Accepted Manuscript • DOI: 10.1021/ acssuschemeng.7b03650 • Publication Date (Web): 06 Dec 2017 Downloaded from http://pubs.acs.org on December 9, 2017

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ACS Sustainable Chemistry & Engineering

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Supertough PLA-silane nanohybrids by in situ condensation and grafting

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Xiangtao Menga,*, Ngoc A. Nguyena, Halil Tekinalpb, Edgar Lara-Curzioa, Soydan Ozcana, b,*

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a

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Road, Knoxville, Oak Ridge, TN 37831, United States

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b

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Knoxville, TN 37996, United States

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Corresponding authors: Soydan Ozcan, Email: [email protected], Tel: +1 865-241-2158;

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Xiangtao Meng, Email: [email protected], Tel: +1 540-200-5467

Materials Science and Technology Division, Oak Ridge National Laboratory, 1 Bethel Valley

Department of Mechanical, Aerospace, Biomedical Engineering, University of Tennessee,

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Abstract

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Brittleness is a key barrier for poly(lactic acid) (PLA) towards broader applications. Supertough

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PLA was achieved by simply mixing a low amount (0.5–1 wt %) of organoalkoxysilane with

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PLA. Three organosilanes, (3-aminopropyl)triethoxysilane (APTES), 3-(triethoxysilyl)propyl

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isocyanate (ICPTES), and trimethoxymethylsilane (MTMS), were selected for this study to

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understand how the functional group on a silane affects the behavior of the PLA-silane hybrids.

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Remarkable improvements in ultimate tensile strain (up to 12 folds) and tensile toughness (up to

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10 folds) were observed in APTES- and ICPTES-modified PLA without any loss in tensile

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strength and modulus. Glass transition temperatures measured by differential scanning

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calorimetry (DSC) and dynamic mechanical analysis (DMA) did not show any obvious decrease.

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We propose that in situ condensation of organosilane and grafting of PLA to form a silica-PLA

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core-shell nanocomplex may be the reason for the improved mechanical properties. Scanning

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electron microscopy (SEM) showed evidence of nanofibrils at fractured surfaces. Dynamic light 1 ACS Paragon Plus Environment

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scattering (DLS) indicated nanoparticle formation (bimodal, 50–200 nm and