Manufacture, physical properties, and degradation of biodegradable polyester microbeads

The conventional microbeads in cosmetics and personal care products comprise non-biodegradable plastics, which pollute the marine environment. In the present study, we used a simple melt-homogenizing method to manufacture microbeads from four biodegradable polyesters, i.e., poly(butylene succinate) (PBS), poly(butylene succinate adipate) (PBSA), poly(lactic acid) (PLA), and poly[(R)-3-hydroxybutyrate] (P(3HB)). We then determined the morphology, compression properties, and biodegradability of each polyester. The microbeads ranged in size from 25 to 200 mu m, were almost spherical, and had smooth surfaces, as verified by scanning electron microscopy (SEM). The single microbeads were subjected to compression tests because their mechanical properties are correlated to their sensory performance. The compression strengths of the four plastic microbeads, which were comparable to those of commonly used microbeads such as polyethylene and polypropylene, were widely distributed. In particular, the PBSA and P(3HB) microbeads were readily biodegradable, as evaluated by enzymatic degradation and sea water degradation tests, indicating their potential as alternatives to conventional microbeads.

Automated summary

This study utilized a simple melt-homogenizing method to produce microbeads from four biodegradable polyesters, which are commonly found in cosmetics and personal care products. The microbeads ranged in size from 25 to 200 μm, had smooth surfaces, and exhibited comparable compression strengths to conventional microbeads like polyethylene and polypropylene. Particularly, poly(butylene succinate adipate) and poly[(R)-3-hydroxybutyrate] microbeads showed high biodegradability and have the potential to replace conventional microbeads.