Editing Composite material (section)

==Overview==
[[File:Cfk heli slw.jpg|thumb|upright|Carbon fibre composite part.]]

Composite materials are created from individual materials. These individual materials are known as constituent materials, and there are two main categories of it. One is the [[matrix (composite)|matrix]] ([[binder (material)|binder]]) and the other [[reinforcement (composite)|reinforcement]].<ref>{{cite web |title=Composite materials - Using materials - AQA - GCSE Chemistry (Single Science) Revision - AQA |url=https://www.bbc.co.uk/bitesize/guides/ztrwng8/revision/6 |access-date=2020-12-18 |website=BBC Bitesize |language=en-GB |archive-date=2021-05-23 |archive-url=https://web.archive.org/web/20210523194850/https://www.bbc.co.uk/bitesize/guides/ztrwng8/revision/6 |url-status=live}}</ref> A portion of each kind is needed at least. The reinforcement receives support from the matrix as the matrix surrounds the reinforcement and maintains its relative positions. The properties of the matrix are improved as the reinforcements impart their exceptional physical and mechanical properties. The mechanical properties become unavailable from the individual constituent materials by synergism. At the same time, the designer of the product or structure receives options to choose an optimum combination from the variety of matrix and strengthening materials.

To shape the engineered composites, it must be formed. The reinforcement is placed onto the mould surface or into the [[molding (process)|mould]] cavity. Before or after this, the matrix can be introduced to the reinforcement. The matrix undergoes a melding event which sets the part shape necessarily. This melding event can happen in several ways, depending upon the matrix nature, such as solidification from the melted state for a thermoplastic polymer matrix composite or chemical [[polymerization]] for a [[thermoset polymer matrix]].

According to the requirements of end-item design, various methods of moulding can be used. The natures of the chosen matrix and reinforcement are the key factors influencing the methodology. The gross quantity of material to be made is another main factor. To support high capital investments for rapid and automated manufacturing technology, vast quantities can be used. Cheaper capital investments but higher labour and tooling expenses at a correspondingly slower rate assists the small production quantities.

Many commercially produced composites use a [[polymer]] matrix material often called a resin solution. There are many different polymers available depending upon the starting raw ingredients. There are several broad categories, each with numerous variations. The most common are known as [[polyester]], [[vinyl ester resin|vinyl ester]], [[epoxy]], [[phenolic resin|phenolic]], [[polyimide]], [[polyamide]], [[polypropylene]], [[PEEK]], and others. The reinforcement materials are often fibres but also commonly ground minerals. The various methods described below have been developed to reduce the resin content of the final product, or the fibre content is increased. As a rule of thumb, lay up results in a product containing 60% resin and 40% fibre, whereas vacuum infusion gives a final product with 40% resin and 60% fibre content. The strength of the product is greatly dependent on this ratio.

Martin Hubbe and Lucian A Lucia consider [[wood]] to be a natural composite of [[cellulose fibre]]s in a [[matrix (biology)|matrix]] of [[lignin]].<ref>{{cite journal |last1=Hubbe |first1=Martin A. |last2=Lucia |first2=Lucian A. |title=The 'love-hate' relationship present in lignocellulosic materials |journal=BioResources |date=2007 |volume=2 |issue=4 |pages=534–535 |doi=10.15376/BIORES.2.4.534-535 |doi-access=free }}</ref><ref>{{cite book |doi=10.1201/9781482269741 |oclc=50869397 |page=5 ff |title=Wood and Cellulosic Chemistry, Revised, and Expanded |date=2000 |last1=Hon |first1=David N.S. |last2=Shiraishi |first2=Nobuo |isbn=978-0-429-17533-6 }}</ref>