New Method Of Carbon Fiber Recovery Developed By University Of Nottingham

Feasible method

For example, high temperature decomposition method, microwave radiation method (for strengthening high temperature decomposition) and fluidized bed method can be used for carbon fiber recovery, but these methods will lead to shorter fiber length and lower fiber grade, resulting in lower fiber properties.

The team studied supercritical water, carbon dioxide, and some organic solvents, including ethanol, methanol and acetone, and finally selected a short chain alcohol, which is a cheap, propanol. Propanol can dissolve the resin in normal condition.

Under moderate pressure (2~7 MPa), propyl alcohol can enter supercritical state, and the required temperature is higher than 200 ~ 450 degrees Celsius.

The critical point of water needs 22.1 MPa of pressure and 374 degrees of high temperature.

Ethanol and methanol are effective in dissolving polyester resins in glass fiber composites, but they do not well dissolve epoxy resins.

The test results show that the recycled carbon fiber has high strength and stiffness, which is 99% of the original strength and rigidity.

But until now, these experiments are still in laboratory operation.

Usage quantity

The gradual increase of carbon fiber recycling has been put on the agenda of many countries.

Carbon fiber reinforced plastics (CFRP) composites were originally used in aerospace, automobile racing and high-end sports products. At present, this material is gradually being applied to many new manufacturing fields.

According to relevant reports, the global carbon fiber market has been growing by two digits in the past 5 years. Although the growth rate may slow down in the future, the growth trend will continue. The output value will increase from US $1 billion 500 million in 2008 to US $2 billion 500 million in 2014.

Compound material

The structure is still rather difficult.

Although landfill is still the cheapest option, most EU Member States promulgated laws in 2004 to prohibit landfill disposal of composite materials, because carbon thermosetting materials are non degradable, which will cause health and safety risks.

At the same time, the direct discarding of carbon fiber composites is not economical.

Therefore, all countries pay great attention to the new methods of carbon fiber recovery.

Carbon fiber recycling has three environmental benefits: it prevents the waste of carbon fiber from being buried once, and recycles carbon fiber components to be recycled many times. The recycling process itself greatly reduces energy consumption.