Superabsorbent biphasic system based on poly(lactic acid) and poly(acrylic acid)

Abstract

In this research work, biocomposites based on crosslinked particles of poly(acrylic acid), commonly used as \nsuperabsorbent polymer (SAP), and poly-L-lactic acid (PLLA) were developed to elucidate the role of the filler (i.e., \npolymeric crosslinked particles) on the overall physico-mechanical behavior and to obtain superabsorbent thermoplastic \nproducts. Samples prepared by melt-blending of components in different ratios showed a biphasic system with a regular \ndistribution of particles, with diameter ranging from 5 to 10 m, within the PLLA polymeric matrix. The polymeric \nbiphasic system, coded PLASA i.e. superabsorbent poly(lactic acid), showed excellent swelling properties, demonstrating \nthat cross-linked particles retain their superabsorbent ability, as in their free counterparts, even if distributed in a \nthermoplastic polymeric matrix. The thermal characteristics of the biocomposites evidence enhanced thermal stability in \ncomparison with neat PLLA and also mechanical properties are markedly modified by addition of crosslinked particles \nwhich induce regular stiffening effect. Furthermore, in aqueous environments the particles swell and are leached from \nPLLA matrix generating very high porosity. These new open-pore PLLA foams, produced in absence of organic solvents \nand chemical foaming agents, with good physico-mechanical properties appear very promising for several applications, \nfor instance in tissue engineering for scaffold production.