Biodegradation of some natural polymers in blends with polyolefines

The biodegradation of two-component blends containing synthetic and natural polymers was studied. Polyethylene, polypropylene and modified polyester w ere used as synthetic components. Three materials of natural origin, i.e. p owdered cellulose, sodium alginate and chitosan in lyophilized form, were u sed as Filers. The samples were prepared in the form of films of different thicknesses and contained various amounts of natural components. In general the content of synthetic components ranged from 50 to 75wt%, natural polym ers 5-21wt% and other additives 11-38wt%. The biodegradation tests were carried out in soil and water. The effect of microorganisms' action on the samples was estimated by the loss of mass, wa ter sorption capacity and electron microscope studies. In some experiments the mass lass exceeds the sum of masses of all introduced natural component s. It means that some art of synthetic polymer is also damaged during biode gradation. Generally the results obtained lead to the conclusion that biodegradability of two-component polymer films depends considerably on the dimensions of t he natural component particles and their distribution in the film. Films co ntaining large and weakly dispersed particles prove to be more sensitive to biodegradation. Accessibility of natural component particles for the bath containing microorganisms plays an important role in the biodegradation cou rse. Films filled with cellulose are better degradable in soil while the fi lms containing sodium alginate biodegrade in aqueous medium more easily. Co pyright (C) 1999 John Wiley & Sons, Ltd.