Role of Surface-Treated Silica Nanoparticles on the Thermo-Mechanical Behavior of Poly(Lactide)

Luca Fambri,Alessandro Pegoretti,Andrea Dorigato

doi:10.3390/app10196731

Abstract

Surface-treated fumed silica nanoparticles were added at various concentrations (from 1 to 24 vol%) to a commercial poly(lactide) or poly(lactic acid) (PLA) matrix specifically designed for packaging applications. Thermo-mechanical behavior of the resulting nanocomposites was investigated. Field Emission Scanning Electron Microscopy (FESEM) micrographs revealed how a homogeneous nanofiller dispersion was obtained even at elevated filler amounts, with a positive influence of the thermal degradation stability of the materials. Modelization of Differential Scanning Calorimetry (DSC) curves through the Avrami–Ozawa model demonstrated that fumed silica nanoparticles did not substantially affect the crystallization behavior of the material. On the other hand, nanosilica addition was responsible for significant improvements of the storage modulus (E′) above the glass transition temperature and of the Vicat grade. Multifrequency DMTA tests showed that the stabilizing effect due to nanosilica introduction could be effective over the whole range of testing frequencies. Sumita model was used to evaluate the level of filler dispersion. The obtained results demonstrated the potential of functionalized silica nanoparticles in improving the thermo-mechanical stability of biodegradable matrices for packaging applications, especially at elevated service temperatures.

Highlights

Starting from the synthesis in the 1960s [1], poly-lactide or polylactic acid (PLA) began to gain successful attention from researchers and industry for the first interesting applications in the biomedical field [2,3], because PLA is a biocompatible and a biodegradable polymer
PLA-Ar805-1 and PLA-Ar805-2 samples were characterized by the presence of iso-dimensional-fumed silica aggregates having a mean dimension of less than
Surface-treated fumed silica nanoparticles were melt-compounded at different amounts with a PLA matrix designed for packaging applications

Summary

Introduction

Starting from the synthesis in the 1960s [1], poly-lactide or polylactic acid (PLA) began to gain successful attention from researchers and industry for the first interesting applications in the biomedical field [2,3], because PLA is a biocompatible and a biodegradable polymer. PLA represents the denomination of a family of polymers derived from lactic-acid or from various lactides; it could be a homopolymer or a copolymer of L-lactic acid and/or. D-lactic acid monomers at different degrees of enantiomeric purity, derived both from oil and from renewable resources [8]. P-L-LA, poly(L-lactic acid), and P-D-LA, poly(D-lactic acid), or poly-L-lactide and poly-D-lactide, are enantiomerically pure semicrystalline polymers, with melting temperatures of about 180 ◦ C and a high crystallinity degree [9].

Methods

Results

Conclusion