Invited Lecture to the First International Conference on Self Healing Materials
18-20 April 2007, Noordwijk aan Zee, The Netherlands
Frank R. Jones
Self-healing composite materials
Wenting Zhang, Dr. Simon Hayes, Prof. Frank Jones
Department of Engineering Materials
University of Sheffield,
Sheffield, UK
Advanced thermosetting polymer composites are susceptible to damage in the form of
cracks, which can lead to the mechanical degradation of polymer materials. The
cracks which form deep in the structure may not be easily detectable to the naked eye
so that repair may not be initiated. Traditional repair methodologies can only achieve
the healing effect by using manual intervention. A self-healing structural polymer
composite material that is capable of repairing these resin cracks automatically and
recovers its structural integrity is sought. It has been shown that the addition of a
macromolecular polymer to an epoxy resin can provide self-healing capability. The
paper will describe the applications of this concept to a variety of resins and
composites. Thus the healing agent should diffuse to crack and cause closure when
heated to an appropriate temperature. Charpy single-notched impact and compact
tension tests were used to measure the effectiveness of the repair technique and the
efficiency of healing recovery of fractured strength relative to the virgin fracture
toughness to 65% was obtained for epoxy resin system as shown below. The healing
efficiency of virgin resin specimens with lower temperature in longer healing duration
can get the similar value with those of at higher temperature in short time. The selfhealing system was sequentially repeatable to several fracture events, it was also
highly reproducible. E-glass fibre reinforced composites with the matrix of this kind
of resin could recover the strength of the materials and obtain the healing of matrix
cracking.
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