Extrinsic and Intrinsic Approaches to Self-Healing Polymers and Polymer Composites

Ming Qiu Zhang, Min Zhi Rong

• Publisher: Wiley
• Year: 2022
• ISBN:
  9781119629979
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Chemical & Biochemical Engineering
• Index: Technology & Engineering

Explore the cutting-edge in self-healing polymers and composites

In Extrinsic and Intrinsic Approaches to Self-Healing Polymers and Polymer Composites, a pair of distinguished materials scientists delivers an insightful and up-to-date exploration of the fundamentals, theory, design, fabrication, characterization, and application of self-healing polymers and polymer composites. The book discusses how to prepare self-healing polymeric materials, how to increase the speed of crack repair, high temperature applications, and how to broaden the spectrum of healing agent species.

The authors emphasize the integration of existing techniques with novel synthetic approaches for target-oriented materials design and fabrication. They provide a comprehensive view of this emerging field, allowing new researchers to gather a firm understanding of the framework for creating new materials or applications. Additionally, the book includes:

• A thorough introduction to the field of self-healing polymers and polymer composites, including the advances made by various laboratories and the challenges, trends, and future directions that characterize modern research in the area
• Comprehensive explorations of the self-healing strategies proposed by the authors, including addition polymerization, systems-based microcapsules and plastic tubes, and more
• Practical discussions of the application of reversible S-S bonds in self-healing polymers
• In-depth examinations of intrinsic self-healing via reversible C-ON bonds

Perfect for polymer and materials scientists, chemists, and engineers, Extrinsic and Intrinsic Approaches to Self-Healing Polymers and Polymer Composites will also earn a place in the libraries of professionals working in the polymer, coatings, paints, medical, defense, and pharmaceutical industries.

1
Basics of Self‐Healing – State of the Art

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CHAPTER MENU

• 1.1 Background
• 1.1.1 Adhesive Bonding for Healing Thermosetting Materials
• 1.1.2 Fusion Bonding for Healing Thermoplastic Materials
• 1.1.3 Bioinspired Self‐Healing
• 1.2 Intrinsic Self‐Healing
• 1.2.1 Self‐Healing Based on Reversible Covalent Chemistry
• 1.2.1.1 Healing Based on General Reversible Covalent Reactions
• 1.2.1.2 Healing Based on Dynamic Reversible Covalent Reactions
• 1.2.2 Self‐Healing Based on Supramolecular Interactions
• 1.2.2.1 Coordination Bonds
• 1.2.2.2 Ionic Associations
• 1.2.2.3 Hydrogen Bonds
• 1.2.2.4 Other Intermolecular Forces
• 1.2.2.5 Host–Guest Inclusion
• 1.3 Extrinsic Self‐Healing
• 1.3.1 Self‐Healing in Terms of Healant Loaded Pipelines
• 1.3.1.1 Hollow Tubes and Fibers
• 1.3.1.2 Three‐Dimensional Microvascular Networks
• 1.3.2 Self‐Healing in Terms of Healant Loaded Microcapsules
• 1.3.2.1 Methods of Microencapsulation
• 1.3.2.2 Healing Chemistries
• 1.4 Insights for Future Work
• References

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1.1 Background

Polymers and polymer composites have been widely used in important engineering fields including aerospace, marine, automotive, surface transport, and sports equipment because of their advantages including light weight, good processibility, and chemical stability in any atmospheric conditions. However, long‐term durability and reliability of polymeric materials are still problematic when they are used for structural applications [1, 2]. This is particularly true when impact resistance is concerned, which is a critical aspect of vehicle design. Their inability to undergo plastic deformation results in energy adsorption via the creation of defects and damage. Besides, exposure to a harsh environment would easily lead to degradation of polymeric components. Comparatively, microcracking or hidden damage is one of the fatal deteriorations generated either during manufacturing or in service as a result of mechanical stress or cyclic thermal fatigue (Figure 1.1). Its propagation and coalescence would bring about catastrophic failure of the materials and hence significantly shorten the lifetime of the structures.

Figure 1.1 Cohesive failures beside plated through holes on copper clad laminates, which used to be produced by thermal stress.

1.1.1 Adhesive Bonding for Healing Thermosetting Materials

Damaged composites or composite structures should be repaired when significant structural degradation is detected [3]. The routine repair procedures for thermosetting composites are shown in Scheme 1.1. Some damage to composites is obvious and easily assessed but in some cases the damage may first appear quite small, although the real damage is much greater. Impact damage to a fiber can appear as a small dent on the reinforced composite surface but the underlying damage can be much more extensive. The decision to repair or scrap is determined by considering the extent of repair needed to replace the original structural performance of the composite [4]. Other considerations are the repair costs, the position and accessibility of the damage, and the availability of suitable repair materials. Easy repairs are usually small or do not affect the structural integrity of the component. Complex repairs are needed when the damage is extensive and the original structural performance of the component needs to be replaced. The best choice of materials would be to use the original fibers, fabrics, and matrix resin. Any alternative would need careful consideration of the service environment of the repaired composite, i.e. hot, wet, and mechanical performance. The proposed repair scheme should meet all the original design requirements for the structure. Some repairs need specialist equipment of a workshop and some form of improvised repair is needed to return the component to a suitable repair workshop. A temporary repair, usually in the form of a patch, can be fixed to the component. Usually a “belt and braces” approach is taken to ensure safety until the component can be repaired at a later date.

Scheme 1.1 Flow chart of the key stages for thermosetting composite repair.

Most damage to fiber reinforced polymer composites is a result of low velocity (and sometimes high velocity) impact [5]. In metals the energy is dissipated through elastic and plastic deformations, and a good deal of structural integrity is retained. In polymer composites the damage is usually more extensive than that seen on the surface. Typical damage is summarized in the following. (i) Delamination following impact on a monolithic laminate. (ii) Laminate splitting, which does not extend through the full length of the part. Its influence on the mechanical performance depends on the length of split relative to the component thickness. (iii) Heat damage, a local fracture with separation of surface plies. Its effect on the mechanical performance depends on the thickness of the part. (iv) Dents in a sandwich structure. (v) Puncture damage in a sandwich structure. (vi) Bolt hole damage, which could be elongation of the hole causing laminate splitting, or damage to the upper plies.

Patch repair, a ...

Table of contents

• Cover
• Table of Contents
• Title Page
• Copyright Page
• Preface
• 1 Basics of Self‐Healing – State of the Art
• 2 Extrinsic Self‐Healing via Addition Polymerization
• 3 Extrinsic Self‐Healing Via Cationic Polymerization
• 4 Extrinsic Self‐Healing via Anionic Polymerization
• 5 Extrinsic Self‐Healing Via Miscellaneous Reactions
• 6 Intrinsic Self‐Healing Via the Diels–Alder Reaction
• 7 Intrinsic Self‐Healing Via Synchronous Fission/Radical Recombinationof the C─ON Bond
• 8 Intrinsic Self‐Healing Via Exchange Reaction of the Disulfide Bond
• Index
• End User License Agreement