Biocomposites based on poly(lactic acid) and superabsorbent sodium polyacrylate

In this research work, biocomposites based on crosslinked particles of sodium polyacrylate, commonly used as superabsorbent polymer, and poly(l-lactic acid) (PLLA) were developed to obtain superabsorbent thermoplastic products, and to elucidate the role of this type of filler (i.e., polymeric crosslinked particles) on their overall physical-mechanical behavior. Samples prepared by melt-blending components with different ratios showed a biphasic system with a uniform distribution of particles, with diameters up to about 50 μm, within the PLLA polymeric matrix. The polymeric biphasic system, coded PLASA, that is, superabsorbent PLLA, showed excellent swelling properties, demonstrating that crosslinked particles retain their superabsorbent ability even if distributed in a thermoplastic polymeric matrix. The thermal characteristics of the biocomposites evidenced enhanced thermal stability in comparison with neat PLLA and also mechanical properties are markedly modified by addition of crosslinked particles, revealing a regular stiffening effect. Furthermore, in aqueous environments the particles swell and are leached from PLLA matrix generating very high porosity. These new open-pore foams coded PLASAW, that is, PLASA after water treatment, produced in absence of organic solvents and chemical foaming agents, with good physicomechanical properties appear very promising for several applications, for instance in tissue engineering for scaffold production.