Yoann Paint

Metallic oxides have been successfully investigated for the recycling of polylactide (PLA) via catalyzed unzipping depolymerization allowing for the selective recovery of lactide monomer. In this contribution, a metallic oxide nanofiller, that is, ZnO, has been dispersed into PLA without detrimental polyester degradation yielding PLA/ZnO nanocomposites directly suitable for producing films and fibers. The nanocomposites were produced by melt-blending two different grades of PLA with untreated ZnO and surface-treated ZnO nanoparticles. The surface treatment by silanization proved to be necessary for avoiding the decrease in molecular weight and thermal and mechanical properties of the filled polyester matrix. Silane-treated ZnO nanoparticles yielded nanocomposites characterized by good mechanical performances (tensile strength in the interval from 55 to 65 MPa), improved thermal stability, and fine nanofiller dispersion, as evidenced by microscopy investigations. PLA/ZnO nanocomposites were further extruded in films and fibers, respectively, characterized by anti-UV and antibacterial properties.

ABSTRACT The influence of the incorporation of hydrophobic nanosilica on morphological and mechanical properties of polyamide 6 (PA) and poly(propylene) (PP) blends has been investigated. Depending on the amount of silica nanoparticles in the blend and the melt mixing procedure, a strong refinement of PP (as minor dispersed phase) droplet size can be achieved thanks to the interfacial confinement of nanoparticles. The accumulation of nanoparticles at the interface allows the formation of an anticoalescence rigid barrier around PP domains that prevents/refrains dispersed phase domains from coalescence as highlighted by transmission and scanning electron microscopies. The mechanical properties of the hybrid blends were also discussed and interpreted in relation with the blend morphology.

ABSTRACT A new approach leading to poly(lactic acid) (PLA) nanocomposites designed with improved nucleating/crystallization ability has been developed. As proof of concept, nanofillers of different morphology (organo-modified layered silicates, halloysite nanotubes and silica) were surface-treated with ethylene bis-stearamide (EBS), a selected fatty amide able to promote chain mobility during PLA crystallization from the melt and nucleation. The fine dispersion of the nucleating additive via nanoparticles (NPs) as ‘nano-template’ is leading to nanocomposites showing unexpected improvements in PLA crystallization rate. This was evidenced by differential scanning calorimetry (DSC) from the high values of the degree of crystallinity (20–40%) with respect to neat PLA (4.3%) and the sharp decrease in crystallization half-time under isothermal conditions (at 110°C), even below one minute. Furthermore, after injection molding the outstanding crystallization properties of PLA were again confirmed. Accordingly, the PLA- nanofiller/EBS nanocomposites revealed remarkable degree of crystallinity (in the range of 30–40%). Surprisingly, the presence of EBS can significantly increase the impact resistance of PLA and PLA based nanocomposites. By considering the remarkable increasing in crystallinity, a key parameter to allow PLA utilization in durable applications, the development of the new approach is expected to lead to significant improvements in the processing and performances of PLA products. To download free the pdf variant please use directly the web site of Nanocomposites journal (W. S. Maney & Son Ltd 2014) : http://www.maneyonline.com/doi/pdfplus/10.1179/2055033214Y.0000000008

Polylactide (PLA), a polyester produced from renewable resources, has a key-position in the market of biopolymers for various applications (packaging, fibers, technical parts). The addition into PLA of selected nanofillers (organo-modified layered silicates, silver, zinc oxide, graphite derivatives, carbon nanotubes, etc.) is actually considered a modern method that can lead to major improvements of PLA properties and to specific end-use characteristics. To the best of our knowledge, we have reported for the first time the possibility to produce PLA-ZnO nanocomposites via melt-blending technology and using a specifically treated nanofiller to limit polyester degradation. These new nanocomposites have been successfully used in the production of fibers, films, or other materials showing multifunctional properties (anti-UV, antibacterial, barrier, etc.) However, it is quite difficult to control ZnO degrading effects at high temperature and long residence time, thus the aim of this stud...

Metallic oxides have been successfully investigated for the recycling of polylactide (PLA) via catalyzed unzipping depolymerization allowing for the selective recovery of lactide monomer. In this contribution, a metallic oxide nanofiller, that is, ZnO, has been dispersed into PLA without detrimental polyester degradation yielding PLA/ZnO nanocomposites directly suitable for producing films and fibers. The nanocomposites were produced by melt-blending two different grades of PLA with untreated ZnO and surface-treated ZnO nanoparticles. The surface treatment by silanization proved to be necessary for avoiding the decrease in molecular weight and thermal and mechanical properties of the filled polyester matrix. Silane-treated ZnO nanoparticles yielded nanocomposites characterized by good mechanical performances (tensile strength in the interval from 55 to 65 MPa), improved thermal stability, and fine nanofiller dispersion, as evidenced by microscopy investigations. PLA/ZnO nanocomposites were further extruded in films and fibers, respectively, characterized by anti-UV and antibacterial properties.