Beschreibung:
<jats:title>Abstract</jats:title><jats:p>In order to increase the molecular weights of poly(ethylene terephthalate‐co‐oxyben‐zoate)s (PET/PHB) these polymers were modified with methylene‐diphenyldiisocyanate (MDI) in the melt to couple the carboxy terminal groups, forming a copolyester amide. Starting from M̄<jats:sub>n</jats:sub> 12 500, various M̄<jats:sub>n</jats:sub> values, partly up to 60 400, were obtained in dependence on the MDI quantity. The copolyester amides were characterized by IR spectroscopy, DSC, M̄<jats:sub>n</jats:sub> and rheological measurements. The MDI modification of PET/PHB causes also an increase in melt viscosity and a decrease in crystallinity in the solid state. Injection molded samples showed a considerable increase in tensile strength, elastic modulus and above all impact strength.</jats:p>