Self-healing materials

By Ankush sharma

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INTRODUCTION

A material with the ability to heal itself autonomically.

Proposed in 1980s as a means of healing invisible micro cracks.

Illinios group of white – pioneer.

Mimicking of biological system.

. Self-activated healing of delamination damage in woven composites, composites, part A : applied science and manufacturing, 2000.

. Self- healing polymeric materials : A review of recent developments, progress in polymer science, 2008.

. Healing of impact damage in woven glass fabric reinforced epoxy composites, composites, part A : applied

science and manufacturing, 2008.2

WHY NEED SELF HEALING MATERIALS?

Built in capability to substantially recover their load transferring ability after damage.

Contribute greatly to the safety and durability of polymeric components.

Capable of continuously sensing and responding to damage overthe lifetime.

Restoring the material performance.

Offers great opportunities for broadening the applications.

Refer to the recovery of properties such as fracture toughness,tensile strength.

. Self- healing polymeric materials : A review of recent developments, progress in polymer science, 2008. 3

Strategies of self healing materials

• Hollow glass fiber repair mechanism.• Microencapsulated healing agent.• Micro vascular network.• Hollow fiber approach.• Inclusion of thermoplastic additives.

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. The world of smart healable materials, progress in polymer science, 2009.

. Self- healing polymeric materials : A review of recent developments, progress in polymer science, 2008.

Hollow glass fiber repair mechanism

5. The world of smart healable materials, progress in polymer science, 2009.

Microencapsulation of healing agent

6. The world of smart healable materials, progress in polymer science, 2009.

Micro vascular network

7. The world of smart healable materials, progress in polymer science, 2009.

Hollow fiber approach

8. Self- healing polymeric materials : A review of recent developments, progress in

polymer science, 2008

Inclusion of thermoplastic additives

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. Self- healing polymeric materials : A review of recent developments, progress in polymer science, 2008

Fracture specimens

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. Self healing structural composite materials, composites, part A : applied science andmanufacturing, 2003.

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. DCPD monomer : low viscosity, excellent shelf life.

. Grubb´s  catalyst : bis (tricyclohexylphosphine) benzylidine ruthenium (IV) dichloride

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Fracture of skeletal structure

11. Fracture testing of a self-healing polymer composite, 2002.

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Resealing of puncture damage

12. Self-healing flexible laminates for resealing of puncture damage, smart materials and

structures, 2009.

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Continued…

. Self-healing flexible laminates for resealing of puncture damage, smart materials andstructures, 2009.

Continued…

. Self-healing flexible laminates for resealing of puncture damage, smart materials andstructures, 2009.

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Quantification of healing

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. Self healing structural composite materials, part A : applied science andmanufacturing, 2003.

. The world of smart healable materials, progress in polymer science, 2009.

Healing of impact damage

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. Healing of impact damage in woven glass fabric reinforced epoxy composites,composites, part A : applied science and manufacturing, 2008.

. UF microencapsulated epoxy :10 wt% and 40 µm.

. (CuBr2 (2-MeIm)4) : 2 wt %

Compression after impact results

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. Healing of impact damage in woven glass fabric reinforced epoxy composites,composites, part A : applied science and manufacturing, 2008.

Continued..

Continued..

. Two dash line – compressive strength of the un impacted laminates, virgin specimen without healing agent.

. Healing of impact damage in woven glass fabric reinforced epoxy composites,composites, part A : applied science and manufacturing, 2008. 18

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. Healing of impact damage in woven glass fabric reinforced epoxy composites,composites, part A : applied science and manufacturing, 2008.

Continued…

Continued..

. Indented composite laminates

. healed in an oven at 140°c for 0.5 h.

. Poly(UF) walled microcapsules containing bisphenol-A epoxy(type E-51).

. Curing agent : 2-Ethyl-4-methylimidazole (2E4Mim). . Healing of impact damage in woven glass fabric reinforced epoxy composites,composites, part A : applied science and manufacturing, 2008. 20

. 

Continued..

. Composite laminates impacted at2 J and then compressed to failure.

. Repaired in hot press under 60 kPaat 140°c for 0.5 h.

. Healing of impact damage in woven glass fabric reinforced epoxy composites,composites, part A : applied science and manufacturing, 2008. 21

. Healing matrix system : Hunstman Araldite LY 1556, GY298 epoxy resins

cured with nadic methylene anhydride and cognis chemicals capcure3-800.

. A self-healing thermosetting composite material, part A : applied science and manufacturing, 2006. 22

Continued..

Fracture mechanisms

23. Microcapsule induced toughening in a self-healing polymer composite, materials

science,2004.

. UF microcapsules containing DCPD prepared by emulsion in-situ microencapsulation.

Continued…

. Microcapsule induced toughening in a self-healing polymer composite, materialsscience,2004. 24

. SEM of fracture plane in epoxy with 11vol%, 180µm UF microcapsules. 

Applications• Automotive industry : Nissan Motor co. Ltd. has commercialized

world´s first self-healing clear coat for car surfaces.

• Trade name : “Scratch Guard Coat“.

• This hydrophobic paint repair scratches ( arising from car washings,off-road driving etc.) on coated car surfaces and effective for 3 years.

. Paint contains high elastic resins that prevent scratches reaching the inner layers of painted car surface.

. Depending on depth of scratch and temperature in the surroundingenvironment, the entire recovery occurs between 1 and 7 days.

25. Self-healing materials Fundamentals, Design strategies, and Applications, WILEY VCH, 2009.

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. Two component polyurethane clear coats from Bayer MaterialScience.

. Trade name of raw material : Desmodur and Desmophen.

. Coating heals small scratches under the influence of heat(sunlight).

. Trick employed to design such coatings is based on use of dense polymernetworks with flexible linkages.

. Self-healing corrosion resistant coatings beneficial for structural metallic components such as steel for achieving long-term service lifewith reduced maintenance cost.

. Biocompatible self-healing composite may extend the service lifeof artificial bone, artificial teeth.

. The very-recent discovery of self-healing rubber may find applicationin toy industry.  

. Self-healing materials Fundamentals, Design strategies, and Applications, WILEY VCH, 2009.

Continued..

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. Reflow effect of self-healing clear coats

Continued..

. Self-healing materials Fundamentals, Design strategies, and Applications, WILEY VCH, 2009.

Conclusions• Methods of incorporating self healing capabilities in polymer

composites can now effectively address numerous damage mechanisms at molecular and structural level.

. Underlying core damage successfully restored to the undamaged strength using vascular self healing system which releases liquidhealing agent into the damage zone created by an impact event.

• Hollow fiber, microencapsulation, thermally initiated healing have greater potential to provide multiple healing capabilities over extended time frames. 

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. Self- healing polymeric materials : A review of recent developments, progress in polymer science, 2008.

. Self-healing sandwich panels : Restoration of compressive strength after impact, composites science and technology, 2008.

.  By establishing the relationship between microcapsule size, microcapsules weight fraction, and crack volume, it is now possible to rationally design self healing systems that are tailored to repair specific type of damage.

. A biomimetic approach has been used to develop and demonstrate a self-repairing enhanced damage visibility bleeding composite which provides an effective way to recover mechanical strength and highlight concealed damage after an impact damage.

. Engineering this self-healing composite involves the challenge ofcombining polymer science, experimental and analytical mechanics,and composites processing principle.

Continued..

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. Effect of microcapsule size on the performance of self-healing polymers, polymer, 2007.

. A hollow fiber reinforced polymer composite encompassing self-healing and enhanceddamage visibility, composites science and technology, 2005.

. Autonomic healing of polymer composites, nature, 2001.

Future outlook

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. Devise a circulatory system where the microcapsules are driven to burst and discharge their entire payload at a damaged region, thereby delivering a high concentration of healing agents to a small area.

. Broaden the concept of attainable methods for initiating repair, the variety of polymer materials and composites capable of healing.

. Introduction of multi-step healing processes will further improve the performance of the new self-healing polymeric materials.

. Refine both the self-repairing and damage enhancement processes by the use of tailored resins and dyes which provide improvedrepair properties, damage enhancement and environment stability/longevity.

. Use an instrumented drop-weight impact tester to create a more realistic damage condition within the material and apply CAI testing in order to achieve a more rigorous assessment of the effects of HGF on the host laminate and the subsequent healing performance.

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THANK YOU

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