Biologically degradable composite materials

For ecological reasons, more activities in the area of biologically degradable composite materials, i.e., natu-... 

Composites made from lignocellulosic materials have been restricted from many markets because of their moisture sorption, dimensional instability, and to a lesser extent, biological degradation. These negative properties can be overcome, allowing flakes, particles, and fiber from wood and agricultural residues to find markets related to high-performance composites. 

Cotton seeds are most popular as cores because the surface of the grain is downy so that it holds the composition very well. Rice chaff is also popularly used for smaller class shells. For larger shells seeds of Japanese cypress are used in mountainous districts and pieces of cork j are also used for the largest shells. In any case core material must be roughly spherical, must hold the composition well, and should not allow the fire to remain in it after the explosion and if possible it should be ultimately biologically degradable. 

The manufacture of composite wood products requires the use of bonding thermosetting resins mentioned before. In addition, to protect these products from biological degradation, (e.g., fungal induced decay), preservatives (insecticides and/or fungicides) are combined with resins or applied separately to the composite material. Other propertymodifying chemicals such as waxes and fire retardants [84] may also be used. 

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