Molecular Interactions and Toughening Mechanisms in Silk Fibroin-Epoxy Resin Blend Films.

Natural silkworm silks have been applied to reinforce epoxy resin to achieve sub-ambient and impact toughness in the composite. However, the molecular interactions at the silk fiber-matrix interface of the composite are poorly understood. In this work, silk fibroin extracted from Bombyx mori silk is blended with an epoxy resin polymer system to study the molecular interactions between silk fibroin, epoxy compounds, and hardeners. The effects of chemical crosslinks between epoxy groups and hardeners or silk fibroin, as well as physical crosslinks in the β-sheet structure of silk fibroin, were discussed on the thermal stability, glass transition behavior, and mechanical properties of the blend films. A relationship between the crosslinking structure and mechanical properties for the films is proposed to enlighten on the toughening mechanisms. The findings would provide insights into forming strong and tough silk fibroin material as well as understanding the interface interactions of silk-epoxy composites.

[1]  R. Ritchie,et al.  Enhancing the Mechanical Toughness of Epoxy-Resin Composites Using Natural Silk Reinforcements , 2017, Scientific Reports.

[2]  K. Numata,et al.  Silk Resin with Hydrated Dual Chemical-Physical Cross-Links Achieves High Strength and Toughness. , 2017, Biomacromolecules.

[3]  K. Numata,et al.  Tensile Reinforcement of Silk Films by the Addition of Telechelic-Type Polyalanine. , 2017, Biomacromolecules.

[4]  M. Mizuno,et al.  A Biomimetic Silk Fibroin/Sodium Alginate Composite Scaffold for Soft Tissue Engineering , 2016, Scientific Reports.

[5]  J. V. van Esch,et al.  Programing Performance of Silk Fibroin Materials by Controlled Nucleation , 2016 .

[6]  Benjamin P. Partlow,et al.  Tyrosine Templating in the Self-Assembly and Crystallization of Silk Fibroin. , 2016, Biomacromolecules.

[7]  R. Ritchie,et al.  High volume-fraction silk fabric reinforcements can improve the key mechanical properties of epoxy resin composites , 2016 .

[8]  K. Numata,et al.  Influence of Water Content on the β-Sheet Formation, Thermal Stability, Water Removal, and Mechanical Properties of Silk Materials. , 2016, Biomacromolecules.

[9]  Zhansheng Guo,et al.  Temperature-frequency-dependent mechanical properties model of epoxy resin and its composites , 2016 .

[10]  Soo-Jin Park,et al.  Synthesis and application of epoxy resins: A review , 2015 .

[11]  M. Baloch,et al.  Solvent induced miscibility between polymers, and its influence on the morphology, and mechanical properties of their blends , 2015 .

[12]  D. Porter,et al.  Can silk become an effective reinforcing fibre? A property comparison with flax and glass reinforced composites , 2014 .

[13]  R. Lewis,et al.  Mechanical and Physical Properties of Recombinant Spider Silk Films Using Organic and Aqueous Solvents , 2014, Biomacromolecules.

[14]  K. Numata,et al.  Short one-pot chemo-enzymatic synthesis of L-lysine and L-alanine diblock co-oligopeptides. , 2014, Biomacromolecules.

[15]  J. Lee,et al.  Interfacial bonding and degumming effects on silk fibre/polymer biocomposites , 2012 .

[16]  D. Kaplan,et al.  Materials fabrication from Bombyx mori silk fibroin , 2011, Nature Protocols.

[17]  Z. Shao,et al.  Understanding the Mechanical Properties of Antheraea Pernyi Silk—From Primary Structure to Condensed Structure of the Protein , 2011 .

[18]  Jinrong Yao,et al.  The preparation of high performance silk fiber/fibroin composite , 2010 .

[19]  T. Peijs,et al.  Improved fracture toughness of carbon fibre/epoxy composite laminates using dissolvable thermoplastic fibres , 2010 .

[20]  Lei Song,et al.  Flame retardancy and thermal degradation mechanism of epoxy resin composites based on a DOPO substituted organophosphorus oligomer , 2010 .

[21]  D. Kaplan,et al.  Effect of hydration on silk film material properties. , 2010, Macromolecular bioscience.

[22]  S. Prasong,et al.  Structure and thermal characteristics of Bombyx mori silk fibroin films: effect of different organic solvents. , 2010 .

[23]  Daiwen Yang,et al.  Solution structure of eggcase silk protein and its implications for silk fiber formation , 2009, Proceedings of the National Academy of Sciences.

[24]  Fritz Vollrath,et al.  Silk as a Biomimetic Ideal for Structural Polymers , 2009 .

[25]  Z. Shao,et al.  Silk Fibers Extruded Artificially from Aqueous Solutions of Regenerated Bombyx mori Silk Fibroin are Tougher than their Natural Counterparts , 2009 .

[26]  David L. Kaplan,et al.  Effect of water on the thermal properties of silk fibroin , 2007 .

[27]  Ray Gunawidjaja,et al.  Mechanical Properties of Robust Ultrathin Silk Fibroin Films , 2007 .

[28]  David L. Kaplan,et al.  Determining Beta-Sheet Crystallinity in Fibrous Proteins by Thermal Analysis and Infrared Spectroscopy , 2006 .

[29]  P Wyeth,et al.  Characterizing the decay of ancient Chinese silk fabrics by microbeam synchrotron radiation diffraction. , 2006, Biomacromolecules.

[30]  R. Naik,et al.  Thermally Induced α-Helix to β-Sheet Transition in Regenerated Silk Fibers and Films , 2005 .

[31]  C. Panayiotou,et al.  Blends of polymers with similar glass transition temperatures: A DMTA and DSC study , 2004 .

[32]  Yingfeng Yu,et al.  Polymerization induced phase separation in poly(ether imide)-modified epoxy resin cured with imidazole , 2004 .

[33]  Hang Zhang,et al.  Thermal properties of Bombyx mori silk fibers , 2002 .

[34]  Fritz Vollrath,et al.  Materials: Surprising strength of silkworm silk , 2002, Nature.

[35]  T. Asakura,et al.  Comparative structure analysis of tyrosine and valine residues in unprocessed silk fibroin (silk I) and in the processed silk fiber (silk II) from Bombyx mori using solid-state (13)C,(15)N, and (2)H NMR. , 2002, Biochemistry.

[36]  F Vollrath,et al.  The effect of spinning conditions on the mechanics of a spider's dragline silk , 2001, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[37]  M. Elices,et al.  Tensile properties of silkworm silk obtained by forced silking , 2001 .

[38]  J. Cauich‐Rodríguez,et al.  Poly(vinyl alcohol)/poly(acrylic acid) blends: Miscibility studies by DSC and characterization of their thermally induced hydrogels , 1993 .

[39]  H. Scheraga,et al.  Conformational energy studies of β‐sheets of model silk fibroin peptides. I. Sheets of poly(Ala‐Gly) chains , 1991 .

[40]  R. Wetton,et al.  DMTA studies of polymer blends and compatibility , 1990 .

[41]  Y. Saegusa,et al.  Physical properties and structure of silk. XI. Glass transition temperature of wild silk fibroins , 1986 .

[42]  N. Kosuge,et al.  Study on Thermal Degradation Mechanism of Epoxy-Amine Resin Coatings by Torsional Braid Analysis , 1982 .