Expert Repair: Self Repairing Polymer

Many consumer goods are made of polymeric materials whose appearance or performance can be altered by impact, scratches or cracks. Driven by manufacturers and consumers, research has increased to extend the life of products.

Self-repairing polymers can provide a satisfactory solution to repair unsightly fractures or damage to specific parts.

There are two different technologies regarding self-healing polymers:

Assisted healing

Assisted wound healing involves encapsulated healing agents, released during the propagation of a crack and reconstituting the material. Because the amount of these agents is limited, the material can only be repaired a certain number of times.

Self-healing

Self-healing (or self-healing) is an inherent healing ability of the material that can heal an infinite number of times. It can involve the movement of polymer chains within the material or allow for the reversible formation of chemical or physical bonds between material constituents.

Focus on a self-healing technique:

Chain creep – Molecular interdiffusion: the case of thermoplastics

In a polymeric material, chain entanglements prevent lateral diffusion of the chains, which then diffuse by creep. The material then behaves like a solid at short times but flutes at longer times. Healing takes place on freshly damaged surfaces, by re-contacting at a temperature above the glass transition (Tg). Gradually, the interface disappears and the mechanical properties at the polymer-polymer interface increase as the crack repairs itself through molecular diffusion at the interface. Increasing the temperature above Tg, as well as increasing the healing time, improves the quality of healing.

Advantages
Temperature and self-healing time can be precisely adjusted over a wide temperature range
ExpertRepair products can be filled and used as a matrix for composite materials
Mechanical properties can be adjusted for a given application
Applications :
Aerospace
Military
Automotive industry
Medical
Cable coating
Tire linings