DEGRADATION PRODUCTS IN DEGRADABLE POLYMERS

Diffusion and migration of small molecules in polymers affect the long -term properties of the materials and also the surrounding environment s. The interaction of such small molecules (i.e., low molecular weight compounds) with the environment are one of the main factors governing in-vitro and in-vivo behavior of degradable polymers. The type and am ount of formed degradation products are the crucial points deciding th e applicability of degradable polymers. The number of low molecular we ight compounds obtained during long-term use of degradable polymers de pends on the polymeric chain. Hydrolyzable polymers like the polyester s give few degradation products (mainly the monomer) where it is possi ble to relate the amount of products formed with the weight loss and t he molecular weight changes. On the other hand, non-hydrolyzable polym ers like polyethylene form hundreds of products in different amounts, thus complicating this comparison. Degradation products of hydrolyzabl e polyesters (PHB, PLLA, PDLLA/PGA, and PAA) as obtained by (head-spac e)-GC-MS are presented. The concept of fingerprinting based on the abi otic and biotic degradation products formed in degradable LDPE (LDPE starch + prooxidant) is described and can be related to our proposed biodegradation mechanism of polyethylene.