Bioplastics processing

Processing recommendations

In the case of these chemically equivalent polymers, the recommendations for processing will be identical in terms of temperature, possible steaming, pressures, etc. It will also be possible here to use already known property modification technologies (masterbatches, colorants, etc.). It will also be possible to use existing technologies for modifying properties (masterbatches, colorants, etc.).

In the case of bioplastics with novel chemical structures, each will have its own specific features in the same way as conventional polymers. Most of these materials are biodegradable, and therefore require special attention to the presence of moisture and the temperatures employed.

Indeed, these biodegradable plastics are polyesters, materials which are by definition sensitive to hydrolysis. The processing temperatures used for these materials in injection and extrusion (generally between 130 and 200°C) make this reaction, typical of polyester degradation, very rapid and potentially significant. Hydrolysis is further facilitated by the fact that the biodegradable nature of these materials makes them more susceptible to this reaction. It is therefore important to ensure that these polymers are efficiently dried, and in some cases a desiccant is required.

Similarly, they are often sensitive to thermal exposure, even in the absence of water. In processes where stagnation phases can be significant (typically injection molding), it is not uncommon to observe thermal degradation of materials when cycle times are too long. These phenomena therefore need to be taken into account when choosing materials, equipment and means of avoiding them (use of additives, etc.).