Cardanol

". The name of the genus itself is based on the Greek word for "heart". [cite book |author=Alexander Senning |title=Elsevier's Dictionary of Chemoetymology |p [ublisher=Elsevier |year=2006 |isbn=0444522395]

Friction particles are made by polymerizing the unsaturated side chain of cardanol, followed by cross-polymerization with phenol to yield a cardanol-formaldehyde resin by a process analogous to the formation of phenol-formaldehyde resins such as Bakelite. Cardanol-phenol resins were developed in the 1920s by Mortimer T. Harvey, then a student at Columbia University. These resins found use in vehicle brakes after it was found that they had a coefficient of friction that was less sensitive to temperature changes than phenol-formaldehyde resins.

Despite all these uses, only a fraction of the cardanol obtained from cashew nut processing is used in the industrial field. Therefore, there is still interest in developing new applications, such as new polymers. [cite journal |journal=Macromolecular Rapid Communications |author=Ryohei Ikeda, Hozumi Tanaka, Hiroshi Uyama, Shiro Kobayashi |volume=21 |issue=8 |pages=496-499 |title=A new crosslinkable polyphenol from a renewable resource |doi=10.1002/(SICI)1521-3927(20000501)21:8<496::AID-MARC496>3.0.CO;2-G]

The name "cardanol" is used for the decarboxylated derivatives obtained by thermal decomposition of any of the naturally occurring anacardic acids. This includes more than one compound because the composition of the side chain varies in its degree of unsaturation. Tri-unsaturated cardanol, the major component (41%) is shown below. The remaining cardanol is 34% mono-unsaturated, 22% bi-unsaturated, and 2% saturated. [cite book |title=Degradable Polymers: Principles and Applications |author=Gerald Scott |publisher=Springer |year=2003 |isbn=1402007906 |pages=192-194]

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In terms of physical properties, cardanol is comparable to nonylphenol. Cardanol is hydrophobic in nature and remains flexible and liquid at very low temperatures; [cite web |title=Cardolite product overview |accessdate=2008-09-08 |url=http://www.cardolite.com/products.htm] its freezing point is below −20 °C, it has a density of 0.930 g/mL, and boils at 225 °C under reduced pressure (10 mmHg). [US patent reference |number=2098824 | y=1937 | m=11 | d=01 | inventor=Mortimer T. Harvey | title=Process of destructively distilling cashew nut shell liquid] CAS registry number: 37330-39-5.

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