1,721,224 research outputs found
INVESTIGATION ON FLAME RETARDANCY AND ANTIDRIPPING OF NOVEL INTUMESCETN FLAME RETARDANT TOWARDS A TRADITIONAL ONE ON POLYPROPYLENE
No full textOptimization of pyrolysis-gas chromatography/mass spectroscopy parameters in order to obtain nanoplastics calibration curves
Full text linkThe issue of plastic pollution is one of the challenges of the coming years. When it comes to agriculture,
this material is widely used, although its degradation leads to formation of micro- and nanoplastics,
whose impact is being studied within the Minagris project. In particular, the identification and
quantification of nanoplastics in soil can be challenging due to their size, which is below the special
resolution of several techniques typically used for the characterization, as Raman or μ-FTIR analysis.
Furthermore, the presence of organic matter or biological agents makes these techniques unsuitable for
this purpose. Pyrolysis-gas chromatography/mass spectroscopy enables to investigate nanosized plastic
samples with low limit of detection (LOD) and limit of quantification (LOQ). In this work, some of the
main types of plastic used in farming have been tested at the nanoscale; with optimized parameters of
py-GC/MS, calibration curves of these polymers have been obtained, in order to test out the likelihood of
analysing them not only qualitatively, but also quantitively. Strong linear correlation has been found
between the peak areas of the markers of each polymer and its quantity under analysis, an outcome
that may be useful for real nanoplastic samples
Towards effective upcycling of polypropylene: evaluation of the introduction of a chain extender on the processability and mechanical properties of recyclates
Full text linkInfluence on the joint effect among expandable graphite and layered clays on poly(ethylene terephthalate) properties
No full text
PLA-PHB BLENDS: THE EFFECT OF DIFFERENT COMPATIBILIZERS AND THE PROCESS PARAMETERS ON MECHANICAL AND RHEOLOGICAL PROPERTIES
No full textIn recent years, it was developed an interest in biodegradable plastics due to the environmental impact of conventional plastics. Particularly there has been an increase in the use of Polylactic acid (PLA). This is one of the most widely used and studied biopolymers. It is a highly transparent, amorphous and rigid material, with a glass transition temperature of around 60°C. It can been processed as a conventional thermoplastic polymer. The main drawbacks of PLA are its high brittleness and low thermal stability. The ways of overcoming these problems are to use plasticizer, copolymerization with others components, making composites and blending with other polymers to obtain a biodegradable plastic with high mechanical properties intermediate between two polymers.. In this work, a blend with Polyhydroxybutyrate (PHB) was chosen.
Specifically, we have studied different compatibilizer systems with different chemical structure to improve the miscibility between PLA and PHB; the thermal and mechanical properties of formulated blends were investigated. Furthermore the process conditions, in terms of, screw configuration and screw speed, have been optimized in order to improve the miscibility of the two phase
Correlation between morphology and processing parameters in polymer blends: preliminary results towards hierarchical structures
Full text linkCyclodextrin nanosponges and phosphorus compounds as flame retardants for ethylene vinyl acetate copolymer
No full textFormation and oxygen diffusion barrier properties of fish gelatin/natural sodium montmorillonite clay self-assembled multilayers onto the biopolyester surface
No full textIn order to expand the application of bio-derived polymers it is imperative that the issues related to their poor gas barrier properties be addressed. Here we explore the sequential layer by layer electrostatic selfassembly approach (abbrev. LbL) for modifying the oxygen transmission rate (OTR) of biopolyesters with the trademark - FF 1482® (abbrev. BP) by deposition of fish gelatin/natural montmorillonite clay (trademark - Cloisite Na+, abbrev. CloNa+). We will show that the deposition of fish gelatin/CloNa+ onto the BP surface is influenced by different process parameters such as dipping time, drying step, polyelectrolyte concentration and surface activation of the BP film via partial alkaline hydrolysis as well as via low pressure plasma. Micro-attenuated total reflectance Fourier-transform infrared spectroscopy (mATR-FTIR) and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) showed that the traditional dipping LbL technique, which involves keeping the film wet throughout all deposition cycles, led to a heterogeneous multilayered structure. The addition of the drying step has proven to be a crucial parameter to obtain a quite homogenous fish gelatin/CloNa+ multi-layered structure. Further, the homogeneity of the multi-layered structure was considerable improved when both the CloNa+ concentration was increased and the BP film surface was activated. By exploiting these processing parameters we were able to achieve successful homogenous fish gelatin/CloNa+ multi-layered structures as shown by SEM/EDS analysis. Further, the optimised samples showed a drastic ecrease in OTR. For example, the OTR value for the sample, in which the BP surface was activated via plasma treatment prior to deposition of fish gelatin/CloNa+, was reduced by 97% of the corresponding value of untreated BP film. This remarkable barrier may be attributed to a greater dispersion of the impermeable inorganic CloNa+ platelets which forces the oxygen molecules to diffuse around them rather than take a straight line pathway that lies perpendicular to the film surface. Thus, this results is a long and tortuous pathway for oxygen molecule diffusion through the multilayered structure
- …
