Search

Polylactide (PLA) is one of the most important bioplastics on the market with a permanent growth in production capacity. Due to its good mechanical properties, it is comparable to polystyrene. But in terms of foaming the melt strength and extensibility of commercial polylactide are rather low. Therefore such commercial grades often need to be chemically modified to induce crosslinking, chain extension or grafting by means of reactive extrusion on a twin-screw extruder. In this work different polylactide grades were used, to better understand the influence of the molecular characteristics, such as molecular weight, acid value and D-content, not only on the modification mechanism, but also on the foam properties. [ABSTRACT FROM AUTHOR]

Bioplastics, which will see rising demand in the next years, have to be compounded by using a twin screw extruder like conventional plastics. By using a twin-screw extruder, the molecular weight of the bioplastic polyhydroxybutyrate (PHB) can be degraded under control. In a second step, the short-chain PHB and a soft phase can be compounded to a larger block copolymer by means of reactive extrusion. The processing step takes place in a process- and material-efficient manner without catalysts, solvents and purification processes. The development of the block copolymer improves the ductile properties of the material without changing the thermal or chemical characteristics. [ABSTRACT FROM AUTHOR]