Synthetic fibers

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Synthetic fibers are fibers which are produced by artificial means. Raw materials are synthesized (joined) to long molecular chains in a process known as polymerization. The polymer is melted or dissolved into a spin-solution. The solution is forced through nozzles having small holes to form long fiber filaments.

As starting material for the synthesis of polymer chains one usually use fractions of oil distillations (naphtha and alkenes), but the first polyamide manufacturing used pentose utilized by corncobs. Today oil chemistry is dominant in the manufacture of synthetic fiber polymers, even if plant material can be used for synthetic fibers such as PLA fiber (Ingeofiber).

The most common synthetic fiber is polyester (PET). Polyamide (PA) which is durable, is also used in industrial applications. Another common synthetic fiber is acrylic. The same synthetic fibers may have different names (trade name), depending on who manufactured it and where it is manufactured.

The major environmental impact from the manufacture of synthetic fibers is that the raw material in the majority of cases are raw oil which is very energy intensive to extract. Oil extraction does not only affect the environment, it is also politically and socially controversial. The oil is polymerized and is converted into polymers that are spun into fibers primarily by melt spinning processes. The polymerization requires different types of chemical catalysts to get the process working (which often is not good for the environment) and then must also chemicals be added to provide the fiber different characteristics. Examples of this is when you want the fibers to be matt or if you want to add optical brighteners.

Polyester is made not only from oil but require much energy to produce. 1 kg polyester requires 109 mega joules of which half is the raw material itself and the other half is spent in production. 1 kg of polyamide requires 150 mega joules, compared with 50 mega joules for cotton. [1]

The high speeds at spinning requires the use of lubricants, spinning lubricants which are mostly mineral oils with additives of surfactants to facilitate washout when dyeing. The production results in emissions of greenhouse gases because of the energy-intensive manufacturing and oil extraction.

• Polyester
• Polyamid

• Textile Environmental Handbook
• [1] Fletcher, Kate, Sustainable Fashion and Textiles - Design journeys