Biocomposites

1. Biocomposites Rene Herrmann

2. Is it new? • Bio Composites are not new, bothnatural and industrial. • Wood is an example of a natural bio composite, see http://en.wikipedia.org/wiki/Wood . In the case the celluslose is the reinforcementhold in place by a biomatrix material, such as sap and othercompounds • An earlyindustrialbiocomposite in naturalrubberreinforced by fibers of eithernatural or syntheticorigin. For fiber see, http://waynesword.palomar.edu/traug99.htm and for naturalrubbersee, http://en.wikipedia.org/wiki/Natural_rubber. Reinforcedrubberproductsplayed an importantrole in the automotiveindustry.

3. Whybiocomposites? (start) • Industrial madesyntheticcompositesuse ester or epoxybasedresin systems and reinforcmentsmade of either glas or carbon fiber for most of the productsmade. • The making of synthetic fibers is at present time not limited by material resource. The process of making is howeververyenergy intensive, seehttp://en.wikipedia.org/wiki/Glass • Drawing a glassfiber seehttp://www.compositesworld.com/articles/the-making-of-glass-fiber, specifically step 3: fiberization • Makeing of carbon fiber see, http://en.wikipedia.org/wiki/Carbon_fiber-reinforced_polymer • Whenlimitingoneselfs to matrix materials such as resins, then the limitingfactor is oil. (excludingrubbers/elastomers etc.) see, http://www.pslc.ws/macrog/petsyn.htm

4. Whybiocomposites?(cont. reinforcment) • Natural fibers such as cotton, sisal, hemp are readilyavailable and processes are known to process these fibers intocloth. Seehttp://en.wikipedia.org/wiki/Natural_fiber for animal and vegetable fibers. • Naturallygrowngrasstypes are one potential reinforcmenttype, premittingenergysaving and light weigthstructures. Observe that gras is a tubedstructure, meaningemthytube. • Mostsignificantlytheir potential productionconsumes far less energythen alternative synthetic fibers

5. Whybiocomposites? (cont. resin) • Resinscan be madebased on mineral oils or biologicaloils. The selection and production of biologicaloils is possible by agriculturalmeans. Mineral oilscanifneeded be made be a high temperature, high pressure process usingcoal. This howeverconsumessignificantenergy. • Polymerization of biologicalresins is morepossible by for exampleepoxytation. • For naturallyavailableresinssee, http://en.wikipedia.org/wiki/Resin and http://en.wikipedia.org/wiki/Sap and for a solifiedexeample of naturalresinseehttp://en.wikipedia.org/wiki/Amber

6. Drawbacks in biocomposites • The production of resinrequires still energy and the process of solidificationrequireschemicals of some form that not necessarilly are naturallyavailable. • The naturalbioresinswillultimatlyhavegreater variation in theirpropertiesthensyntheticresins. • All bioreinforcementswillsuffer from rottening and degradation at a much faster rate thensynthetic fibers. Limitingtheirapplication to products with shorter life time.

7. Advantages with biocomposites • Light weigthstructures from tubedreinforments • Localproduction of fibers/reinforcements, recycability of products • Green production policy is a sales argument • Example of biocomposites are seen at, http://en.wikipedia.org/wiki/Biocomposite and https://www.arthrex.com/innovations/index.cfm?adid=3 as well as pdf’sseen at courseshomepage.