Search results for "blend"
showing 10 items of 421 documents
A step forward in disclosing the secret of stradivari's varnish by NMR spectroscopy
2017
It is commonly thought that the varnishes used by the great violin-maker Antonio Stradivari may have a role in determining not only the esthetical features but also the acoustic properties of his instruments, and the idea of a “lost secret” is still widespread among musicians and violin-makers. Previous scientific researches on varnish samples of Stradivari's instruments revealed that they were generally made by a mix of linseed oil with and colophony or metal rosinates in different ratios ranging between 75/25 (oil/resin) and 60/40 (oil/rosinate). However, it is still not clear whether the mixture composition can be related to any structural and/or functional feature of the resulting varni…
Gas Barrier, Rheological and Mechanical Properties of Immiscible Natural Rubber/Acrylonitrile Butadiene Rubber/Organoclay (NR/NBR/Organoclay) Blend N…
2020
In this paper, gas permeability studies were performed on materials based on natural rubber/acrylonitrile butadiene rubber blends and nanoclay incorporated blend systems. The properties of natural rubber (NR)/nitrile rubber (NBR)/nanoclay nanocomposites, with a particular focus on gas permeability, are presented. The measurements of the barrier properties were assessed using two different gases—O2 and CO2—by taking in account the blend composition, the filler loading and the nature of the gas molecules. The obtained data showed that the permeability of gas transport was strongly affected by: (i) the blend composition—it was observed that the increase in acrylonitrile butadiene rubber compon…
“Compatibilization” through Elongational Flow Processing of LDPE/PA6 Blends
2018
Polyamide/polyolefin blends have gained attention from the academia and the industry for several years. However, in order to optimize their properties, some drawbacks such as chemical incompatibility must be adequately overcome. This can be done by adding suitable compatibilizers. On the other hand, it is less known that suitable processing techniques may also lead to significant results. In a previous work on a low-density polyethylene/polyamide 6 (LDPE/PA6) blend, we found that the orientation due to elongational flow processing conditions could lead to an unexpected brittle&ndash
Diarylethenes in Optically Switchable Organic Light-Emitting Diodes: Direct Investigation of the Reversible Charge Carrier Trapping Process
2021
Advanced optical materials 10, (2021). doi:10.1002/adom.202101116
Rheological, mechanical and morphological characterization of monopolymer blends made by virgin and photo-oxidized polypropylene
2021
In this work, monopolymer blends of virgin polypropylene and photo-oxidized polypropylene were prepare and characterized. The polypropylene samples were subjected to accelerated ageing to simulate the effects of outdoor exposure of polypropylene. After exposure, samples were pelletized and mixed with the same virgin polymer. The rheological, mechanical and morphological characterization was conducted on both the polymers and the blends. Both viscosity and mechanical properties decrease with increases in the content of recycled, photo-oxidized components and of the level of degradation of this component. In addition, the experimental data were compared with a model that takes into account bo…
Self-Assembly of Polymer Blends and Nanoparticles through Rapid Solvent Exchange.
2019
Molecular dynamics simulations were performed to study the fabrication of polymeric colloids containing inorganic nanoparticles (NPs) via the flash nanoprecipitation (FNP) technique. During this process, a binary polymer blend, initially in a good solvent for the polymers, is rapidly mixed with NPs and a poor solvent for the polymers that is miscible with the good solvent. The simulations reveal that the polymers formed Janus particles with NPs distributed either on the surface of the aggregates, throughout their interior, or aligned at the interface between the two polymer domains, depending on the NP-polymer and NP-solvent interactions. The loading and surface density of NPs can be contro…
Morphology, Rheological and Mechanical Properties of Isotropic and Anisotropic PP/rPET/GnP Nanocomposite Samples
2021
The effect of graphene nanoplatelets (GnPs) on the morphology, rheological, and mechanical properties of isotropic and anisotropic polypropylene (PP)/recycled polyethylene terephthalate (rPET)-based nanocomposite are reported. All the samples were prepared by melt mixing. PP/rPET and PP/rPET/GnP isotropic sheets were prepared by compression molding, whereas the anisotropic fibers were spun using a drawing module of a capillary viscometer. The results obtained showed that the viscosity of the blend is reduced by the presence of GnP due to the lubricating effect of the graphene platelets. However, the Cox–Merz rule is not respected. Compared to the PP/rPET blend, the GnP led to a slight incre…
Cooperativity Scaling and Free Volume in Plasticized Polylactide
2019
The authors would like to thank the region Haute Normandie for their financial support and the acquisition of the Broadband Dielectric Spectrometer. R.G. acknowledges U.S. National Science Foundation (Grant no. DMR-1725188) for the acquisition of PAL spectrometer. The experimental evidence of the increase of activation energy associated with the super Arrhenius behavior governing amorphous polylactide by free volume variations has been obtained through a combination of calorimetric, dielectric, and positron annihilation lifetime measurements. The amount of free volume in polylactide was controlled by the amount of acetyltributylcitrate plasticizer in the composition. Plasticization is shown…
Chain Conformations and Phase Behavior in Confined Polymer Blends
2007
We investigate the chain conformations and phase separation in binary polymer blends. Using large scale semi-grandcanonical Monte Carlo simulations and finite size scaling, we investigate the molecular extension and the intermolecular paircorrelation function in thin films with hard, non-preferentially adsorbing surfaces. The interplay between chain conformations, demixing and the validity of mean field theory is investigated for a large variation of chain lengths 16 ≤ N ≤ 512. Three regimes of film thickness D can be distinguished: (i) For film thicknesses much larger than the unperturbed chain extension R e, bulk behavior is observed, i.e., the critical temperature of demixing T c increas…
Spinodal Decomposition in Binary Polymer Blends: Monte Carlo Simulations and Dynamic Mean Field Theory
2001
Using large scale computer simulations we have investigated the interplay between single chain dynamics and the kinetics of phase separation in a symmetric binary polymer blend. In the framework of a coarse grained lattice model — the bond fluctuation model on a three dimensional lattice — we monitor the growth of concentration fluctuations after a quench from the one phase region into the miscibility gap. Chains of 64 effective segments are simulated in a cell of linear dimension L = 160, i.e., each simulation box contains 256 000 particles. The growth rate of composition fluctuations is averaged over 64 realizations of the temperature quench.