hmm....hemp composites anyone?
Posted: Mon Nov 03, 2003 5:43 pm
i was just reading an article on the use of hemp in fiberglass in cars. here's the article (from new scientist magazine, oct. 11-17, 2003)...perhaps it could be used in pole production?
car makers could benefit from a technique which gives the strength of fiberglass composites. this new material could replace conventional composites in car parts such as bumpers and body panels. hemp fiber has been used for centuries to make clothes, sails, ropes, etc. it has recently attracted the attention of the car industry because it is cheaper than glass fiber. but until now, materials reinforced with hemp tended to be weak and used for low-strength components such as interior panelling. Individual hemp fibers, consisting of polymer chains are hugely strong. Hemp's weakness arises from the way its fibers bind together as they grow. Bundles the width of human hair are held together with the weak natural glues lignin and pectin, and it is these bundles that are used to reinforce plastics. When creating material, the trick is to use a polymer that will bind strongly to the bundles to anchor them firmly in place. but because the fibers with hemp bundles are held together so weakly, they tend to slide againsty each other under stress, which weakens the composite. but two canadian researchers have now discovered how to remove the glues from the hemp bundles leaving only the fibers. Mohini Sain and Bhuwan Prasad at the University of Toronto, Canada, found that when the bundles were heated to more than 180 Celsius, the bundles came apart. hey think the glues probably leach out of the bundles and form a hard coating on the fibers. Treated fibers can produce composites 60% of the strength of plastics reinforced with glass fiber. And mixing four parts hemp fiber with one part glass fiber results in a composite as strong and stiff as fiberglass.
car makers could benefit from a technique which gives the strength of fiberglass composites. this new material could replace conventional composites in car parts such as bumpers and body panels. hemp fiber has been used for centuries to make clothes, sails, ropes, etc. it has recently attracted the attention of the car industry because it is cheaper than glass fiber. but until now, materials reinforced with hemp tended to be weak and used for low-strength components such as interior panelling. Individual hemp fibers, consisting of polymer chains are hugely strong. Hemp's weakness arises from the way its fibers bind together as they grow. Bundles the width of human hair are held together with the weak natural glues lignin and pectin, and it is these bundles that are used to reinforce plastics. When creating material, the trick is to use a polymer that will bind strongly to the bundles to anchor them firmly in place. but because the fibers with hemp bundles are held together so weakly, they tend to slide againsty each other under stress, which weakens the composite. but two canadian researchers have now discovered how to remove the glues from the hemp bundles leaving only the fibers. Mohini Sain and Bhuwan Prasad at the University of Toronto, Canada, found that when the bundles were heated to more than 180 Celsius, the bundles came apart. hey think the glues probably leach out of the bundles and form a hard coating on the fibers. Treated fibers can produce composites 60% of the strength of plastics reinforced with glass fiber. And mixing four parts hemp fiber with one part glass fiber results in a composite as strong and stiff as fiberglass.