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ARE NATURAL FIBER COMPOSITES ENVIRONMENTALLY SUPERIOR TO GLASS FIBER REINFORCED COMPOSITES?
INTRODUCTION:-
• Natural fibers have been used to reinforce materials for
over 3,000 years.
• Many types of natural fibers have been investigated for
use in plastics .including , Flax, hemp, jute, straw,
wood fiber, rice husks,wheat,barley,oats .
• Natural fibers have the advantage that they are
renewable resources and have marketing appeal.
• Natural fibers are increasingly used in automotive and
packaging materials.
Agricultural wastes can be used to prepare fiber reinforced polymer composites for commercial use
 Glass fiber-reinforced plastic is a fiber reinforced polymer made of
a plastic matrix reinforced by fine fibers made of glass.
 Glass fiber-reinforced polymer is a lightweight, strong material with many
uses, including boats, automobiles, water tanks, roofing, pipes, cladding and
external door skins.
 The plastic matrix may be epoxy, a thermosetting plastic (most
often polyester or vinylester) or thermoplastic.
MANUFACTURING PROCESSES
 Natural fiber-reinforced polymer
 Hand Laminating
• The fibers, usually, mats are cut and placed in a mould.
• The resin is applied by rollers.
• while using a vacuum bag, excess air is removed and the atmospheric pressure exerts
pressure to compact the composite.
• A possible product is the boat hull shown in fig b.
 Hot Press Method
• pressure and temperature are applied simultaneously.
• This method makes the molded article denser and stronger by reducing porosity.
• Protective atmospheres are usually employed.
• Graphite is a commonly used punch and die material
 Spray-Up (Chopping)
• Spray-up or chopping is an open mold method similar to hand lay-up .
• Suitability for making boats, tanks, transportation components and tub/shower units.
• A chopped laminate has good conformability and is sometimes faster than hand lay-up in
molding complex shapes.
• Although production volume per mold is low.
• It is feasible to produce substantial production quantities using multiple molds.
 Glass fiber- reinforced polymer
 The manufacturing process for GFRP fiber glass uses large furnaces to gradually melt the sand/chemical mix to liquid form.
 Then extrude it through bundles of very small orifices .
 These filaments are then sized with a chemical solution.
 The individual filaments are now bundled together in large numbers to provide a roving.
 The diameter of the filaments, as well as the number of filaments in the roving determine its weight.
 These rovings are used directly in a composite application such as pultrusion, filament winding (pipe).
Comparison of properties
NFRP and GFRP
• lower environmental impacts of natural fiber production compared to glass fiber production.
• Production of natural fibers results in less severe environmental impacts compared to production of glass fibers.
• Natural fiber cultivation depends mainly on solar energy.
• On the other hand, glass production and glass fiber production are both energy intensive processes depending mainly on fossil fuels.
• NFRP components typically will have a higher fiber volume fraction compared to GFRP components .