self-healing plastics black white

8/9/2019 Self-Healing Plastics Black White

1/5

1

SELF-HEALING PLASTICSTERNA COLEGE OF ENGINEERING, OSMANABAD.

Presented by:

HASHMI MD ABDUL RASHEED.

[email protected]

DIMARI KAMLESH B. [email protected]

Cell no.9969569367

Abstract:

Plastic over time naturally gets weaker, no matter how well made it is, becauseover time microscopic cracks form in the plastic that become weak points in the structurethat will only degrade into ever larger cracks. It becomes important to heal these

microscopic cracks before they can grow larger and become an actual problem.

A new kind of plastic is being developed that contains very small balloonsfilled with liquid. The liquid contains monomer molecules, the building material ofplastic. A new solid plastic that contains a special chemical has been already developed.This chemical is used as catalyst.

The new plastic still cracks like common plastic. But, when it does, themonomer liquid is released and flows into the crack. The catalyst in the solid plasticthen reacts with the liquid monomer. The chemical reaction between the liquid monomerand the catalyst creates polymer molecules that repair the break. The repaired plastic has

seventy-five percent of the strength of undamaged plastic.Overall the embedded small balloons provide two independent effects: the

increase in virgin fracture toughness from general toughening and the ability to self-healthe virgin fracture event.Introduction:

Microencapsulated dicyclopentadiene (DCPD) healing agent and GrubbsRucatalyst are incorporated into an epoxy matrix to produce a polymer composite capable ofSELF-HEALING.

Healing is achieved by incorporating a microencapsulated healing agent and a

catalytic chemical trigger within a polymer matrix. A propagating crack ruptures themicrocapsules and exposes catalyst particles. Crack opening draws the healing agent intothe crack plane, where contact with the catalyst phase initiates polymerization. Thepolymerized healing agent reestablishes structural integrity across the crack plane.
mailto:[email protected]:[email protected]:[email protected]:[email protected]


2/5

1

Chemicals in use:

DICYCLOPENTADIENE:

Dicyclopentadiene, abbreviated DCPD, is the chemical compound with theformula C10H12. At room temperature, it is a white crystalline solid with a camphor-like

odor. Dicyclopentadiene is coproduced in large quantities in the steam cracking ofnaphtha and gas oils to ethylene. The major use is resins, particularly unsaturatedpolyester resins.

When heated above 100 C, dicyclopentadiene undergoes a reaction to yieldcyclopentadiene, a compound important in both organic and inorganic chemistry. Thereaction is reversible and at room temperature cyclopentadiene slowly dimerizes toreform dicyclopentadiene.Dicyclopentadiene is a monomer in polymerization reactions.

PRICE:-High, $0.30 per pound & low, $0.28

IUPAC name 3a,4,7,7a-Tetrahydro-4,7-methano-1H-indene

Other names 1,3-Dicyclopentadiene

Molecular formula C10H12

Molar mass 132.20 g/mol

Density 0.98 g/cm3

Melting point 32.5 C

Boiling point 170 C


3/5

1

The product should find use as an intermediate for UPR (unsaturated polyesterresins ) and petroleum resins, but higher end uses are targeted. In marine use, DCPD hasbeen increasingly substituted for unsaturated polyesters. The C10 structure has analcohol group and a double bond which may be used in innovative ways.

EPOXY MATRIX:

In chemistry, epoxy orpolyepoxide is a thermosetting epoxide polymer thatcures (polymerizes and crosslinks) when mixed with a catalyzing agent or "hardener".

Most common epoxy resins are produced from a reaction between epichlorohydrin and bisphenol-A. The chemistry of epoxies and the range of commercially availablevariations allow cure polymers to be produced with a very broad range of properties. Ingeneral, epoxies are known for their excellent adhesion, chemical and heat resistance,good-to-excellent mechanical properties.

Fig. Structure of unmodified epoxy prepolymer. n denotes the number of polymerizedsubunits and is in the range from 0 to about 25

When epoxies are mixed with the appropriate catalyst, the resulting reaction isexothermic, and the oxygen on the epoxy monomers is "flipped." This occurs throughoutthe epoxy, and a matrix with a high stress tolerance is formed, and "glues" the materialstogether.

GRUBBS CATALYST:

Ruthenium carbene complex was invented by chemistry professor Robert H.Grubbs. The Grubbs' catalyst is ideal because it remains active even on exposure to air,moisture, or most organic functional groups.


4/5

1

Fig: Structure of Grubbs Catalyst, ruthenium carbium.

Molecular formula C43H72Cl2P2Ru

Molar mass 822.96 g/mol

Appearance Purple Solid

CAS number [172222-30-9]

Melting point 153 C (426 K)

Grubbs' Catalyst is a transition metal carbene complex named after the chemist bywhom it was first synthesized, Robert H. Grubbs. In contrast to other olefin metathesiscatalysts, Grubbs' Catalysts tolerate other functional groups in the alkene and arecompatible with a wide range of solvents. For these reasons, Grubbs' Catalysts areextraordinarily versatile.

Process:The microcapsules could be produced by high-speed stirring of an aqueous

mixture of urea and formaldehyde, dicyclopentadiene, resorcinol acid catalyst, andethylene-maleic anhydride resin emulsifying agent. The product is microcapsules of urea-formaldehyde resin containing dicyclopentadiene liquid.

To make their composite system, stir 10% by weight of resinmicrocapsules 100 microm in diameter into the epoxy formulation. They cure the moldedepoxy for 24 hours at room temperature followed by a 24-hour bake at 40 C. Thepolymerization catalyst dispersed throughout is a ruthenium carbene complex invented bychemistry professor Robert H. Grubbs of California Institute of Technology. The Grubbscatalyst remains active even on exposure to air, moisture, or most organic functional

groups.


5/5

1

Self-healing of cracks:

HEAL THYSELF

Video images show a crack rupturing a microcapsule, which releases dicyclopentadiene.The capsules contents were dyed red to aid visualization of the flow.

Conclusion:

1) The addition of microcapsules produced a transition of the fracture plane

morphology to hackle markings.

2) Addition of DCPD-filled urea-formaldehyde (UF) microcapsules yields up to

12.7% increase in fracture toughness and induces a change in the fracture plane

morphology to hackle markings.

3) Overall the embedded microcapsules provide the independent effect to self-heal

the virgin fracture event.

Future scope:

On large scale production, it has several uses.

1) One could be for things that are impractical to fix on a regular basis, like partsdeep inside air plane wings or space ships.

2) It can be used in manufacturing automobile parts like bonnet, hood etc.. whichwont get scratched or crack.

3) And it could be used in people, to replace bone joints that have become broken ordamaged. These include knees or hips.

self-healing plastics black white

Documents