We can define “composites” to materials in which a matrix is reinforced with a fibrous material. 

Simple definition

  • A composite material is composed of at least two materials, which combine to form a new component with additional performances.

Full definition

  • Composite materials are microscopic or macroscopic combinations of two or more distinct engineered materials, non-miscible. The physical and chemical properties of each of the constituent materials remain distinct in the new material. The materials are separated by a distinct interface.
  • These constituent materials work synergistically to produce a composite material that has improved properties when compared with the individual constituent materials. In essence, composite materials are heterogenous.

Each word in this definition is important:

  • “polymer” (or plastic) matrices are most important in volume and value terms,
  • fibrous” reinforcements have a considerable length-over-diameter ratio (or “aspect ratio”), excluding spherical or ellipsoidal “inclusions” – when these are added to polymers, the resulting materials are called “particle reinforced “ materials- . Continuous fibres have an infinite aspect ratio, discontinuous or short fibres have finite aspects ratios (ranging from 10 to many thousands); higher aspect ratios result in higher stiffness and strength of the composite.
  • reinforcement” indicates that this phase has mechanical properties superior to those of the matrix, in terms of stiffness and/or strength and/or toughness and/or…

Learn more about the history of composite materials

History of composites

JEC Group commissioned Ignaas VERPOEST, Emeritus Professor at the Composite Materials Group of the Department of Materials Engineering, Katholieke Universiteit Leuven, to document the history of composites and its key milestones and achievements. Focus is on the most important breakthroughs (“disruptive” innovations). The hundreds of “incremental innovations” in academia and industry have been important as well but describing them all would lead to a few hundreds of pages.

Ignaas VERPOEST was assisted by an international advisory board consisting of Frédéric REUX, Editor in Chief, JEC Composites Magazine; Franck GLOWACZ, Innovation Content Leader, JEC Group; Dale BROSIUS, Chief Commercialisation Officer, Institute for Advanced Composites Manufacturing Innovation (IACMI), Kenichi YOSHIOKA, General Manager Composite Materials Research Laboratories, Toray Composites and Christophe BINETRUY, Professor, Ecole Centrale de Nantes.