Biopolymers are around for quite some years and gradually started finding applications in various fields. The initial application areas were in the field of disposable packaging while the source of extraction of raw material used to be from renewable resources like potatoes or corn. Because of its unique advantages and being ecofriendly, it started finding applications in the areas of sheet or film extrusion.
But biopolymers have started finding their applications now in the field of injection molding as well wherein the targeted area of applications right now are medical parts, consumer products, disposable cutlery ,rigid packaging etc.
When we say biopolymer , the first name coming to our mind is PLA. [Poly Lactic Acid. ] But there are several other polymers being developed over the years and all are unique in their respective application areas. PTT/PVOH/PHA/CNF/Mater-Bi etc. would be few such polymers to name. There are in fact many such.
Stainless steel screws with low shear rate and shorter L/D ratio has shown better performance while raw material manufacturers recommend that even general purpose screws used for ABS etc. can also process biopolymers. These are hygroscopic material having a small processing window. So Pre drying of polymers are must and a PVC like screw specially when injection molding of PLA will give better result than general purpose screws.
Next post will cover more details on processing these polymers.
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