NEW COPOLYAMIDES BASED ON ADIPIC ACID, ALIPHATIC DIAMINES AND AMINO-ACIDS - SYNTHESIS, CHARACTERIZATION AND BIODEGRADABILITY .5.

Novel series of biodegradable copolyamides were synthesized via melt copolymerization. The statistical copolyamides were produced by reaction of the salt of adipic acid (AA) and bis(para-aminocyclohexyl)methane (PACM) or isophoronediamine (IPD)/alpha-amino acids at 250 degrees C. Elemental analyses, density, viscosity, differential thermal analysis (DTA) and gel-permeation chromatography (GPC) measurements and FT-IR spectroscopy were employed for the characterization of these copolyamides. The semicrystalline (AA/PACM/alpha-amino acids) or amorphous (AA/IPD/alpha-amino acids) nature of these copolyamides was shown with DTA and wide angle X-ray diffraction patterns. Several methods were used in order to investigate and assess their biodegradability such as alkaline hydrolysis (10% w/v NaOH, 80 degrees C), burial in soil (microbial and bacterial attack) and enzymatic hydrolysis (alpha-trypsin and alpha-chymotrypsin). The degradation of the copolyamides was evaluated with the aid of GPC and DTA measurements and correlated to the alpha-amino acid content. These copolyamides could eventually find applications in the field of food packaging and agriculture (disposable plastics) and medicine (sutures).