Biocomposites are a category of structural and packaging materials. A wide variety of durable space-filling substances used in industry can be replaced with biocomposites. Examples include fiberglass, polyurethane, gypsum board, and cement. In contrast to these, biocomposites are made of plant or animal material and are biodegradeable or sustainable substitutes.
The name and designation of biocomposites are relatively new, but the choice is familiar as "paper or plastic?" Wood is a building material; cotton is available for packing and wrapping.
New biocomposites are available as well, and they fall into a few categories:
Structural items can be rigid panels suitable for construction. These may be plastic-like organics derived from plant oil, or they may be bundles of stiff fibers from flax. Because structural items are meant to replace wooden beams and panels, they are built to the same dimensions, as in this demonstration house (right). Only a portion needs to be rigid, and the remaining volume is usually filled with an insulating material.
Fabrics are not replacing cloth as much as rubber mats and soft plastic panels. Biocomposite fabrics can be woven of flax or hemp and possibly sealed with a binding agent.
Space fillers for insulation or noise suppression are loose material that may be made from sawdust or plant husks. This material can be blown into walls and poured into boxes before shipping.
Adhesives, glues, and binding materials may be variations on plant resins. Adhesives can hold panels together or bind loose biocomposite solids into a cement (right).
A few favorite sources of biocomposites are mentioned again and again. Peanut oil is an example, as it is for biofuel. Flax and hemp are fibrous plants. Corn and quite a few other plants produce husks or seeds or stalks that would otherwise be waste. These are all sources that are readily available in volume.
Advantages of biocomposites include sustainability and nonpermanence after use. Petroleum chemistry uses a limited resource, but plants and animals are renewable. Also, some biocomposites use inputs that would otherwise be waste products.
A couple of disadvantages must be considered. Some biocomposites do not do well in humid environments. Either they absorb water or they degrade. Also, these organic substances may be attacked by termites and bacteria that would ignore plastic, stone, and steel.