Solubility of multiple gases in amorphous polypropylene

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Modelling of a multizone circulating reactor for propylene polymerization: Impact of thermodynamic model

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Gas phase ethylene polymerization: What is the influence of condensed mode

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Low-field high-resolution PFG-NMR to predict the size distribution of inner droplets in double emulsions

In double emulsions, the inner and outer droplet size distribution (DSD) determines the quality of the double emulsion and is therefore essential to be measured. Low-field high-resolution pulsed-field gradient nuclear magnetic resonance is used to measure the inner DSD in water-in-oil-in-water double emulsions. The Gaussian phase distribution approach is employed with a mixture of two normal distributions to predict bimodal inner droplets. This approach allows the prediction of the swelling of inner droplet during storage of double emulsions, and thus to validate a phenomenological population balance model estimating inner droplet swelling. Only a fraction of the inner droplets are found to swell during storage, due to differences in the Laplace pressure, thus leading to the formation of a bimodal size distribution of the inner droplets. Practical Applications: This methodology is useful to predict the evolution of double emulsions during storage, in a wide range of applications, such as food and pharmaceutical products

"Nanohybrids" based on pH-responsive hydrogels and inorganic nanoparticles for drug delivery and sensor applications.

Allyl-PEG capped inorganic NPs, including magnetic iron oxide (IONPs), fluorescent CdSe/ZnS quantum dots (QDs), and metallic gold (AuNPs of 5 and 10 nm) both individually and in combination, were covalently attached to pH-responsive poly(2-vinylpyridine-co-divinylbenzene) nanogels via a facile and robust one-step surfactant-free emulsion polymerization procedure. Control of the NPs associated to the nanogels was achieved by the late injection of the NPs to the polymerization solution at a stage when just polymeric radicals were present. Remarkably, by varying the total amount of NPs injected, the swelling behavior could be affected. Furthermore, the magnetic response as well as the optical features of the nanogels containing either IONPs or QDs could be modified. In addition, a radical quenching in case of gold nanoparticles was observed, thus affecting the final nanogel geometry

Effect of the addition of salt to Pickering emulsion polymerizations using polymeric nanogels as stabilizers

Nanogels made from crosslinked block copolymer micelles are used as stabilizers in the Pickering emulsion polymerization of styrene. The effect of the addition of salt, i.e. NaCl, on the emulsion polymerization is studied. It is shown that an increase in ionic strength of the dispersing medium in these polymerizations led to the formation of latexes of larger diameters. Along with an increase in size, the morphology of these polymer colloids changed from Janus to patchy with an increase in number of nanogels adsorbed on the polymer surface, as a function of the salt concentration in water. In particular, at the highest tested ionic strength, ca. 25 mM, fully armored polymeric particles surrounded by a dense layer of adsorbed stabilizing nanogels were formed. Kinetic studies carried out at varying NaCl concentrations suggested that particle formation in the reaction followed a combination of a coagulative nucleation mechanism, characterized by a clustering process of Janus precursors to form bigger aggregates, and droplet nucleation. Preliminary film formation studies on latexes made with n-butyl acrylate as a comonomer indicated the potential of this technique for the production of coherent polymer films which included a substructure of functional nanogels

Physical Methods for the Preparation of Hybrid Nanocomposite Polymer Latex Particles

In this chapter, we will highlight conceptual physical approaches towards the fabrication of nanocomposite polymer latexes in which each individual latex particle contains one or more "hard" nanoparticles, such as clays, silicates, titanates, or other metal(oxides). By "physical approaches" we mean that the "hard" nanoparticles are added as pre-existing entities, and are not synthesized in situ as part of the nanocomposite polymer latex fabrication process. We will narrow our discussion to focus on physical methods that rely on the assembly of nanoparticles onto the latex particles after the latex particles have been formed, or its reciprocal analogue, the adhesion of polymer onto an inorganic nanoparticle. First, will discuss the phenomenon of heterocoagulation and its various driving forces, such as electrostatic interactions, the hydrophobic effect, and secondary molecular interactions. We will then address methods that involve assembly of nanoparticles onto or around the more liquid precursors (i.e., swollen/growing latex particles or monomer droplets). We will focus on the phenomenon of Pickering stabilization. We will then discuss features of particle interaction with soft interfaces, and see how the adhesion of particles onto emulsion droplets can be applied in suspension, miniemulsion, and emulsion polymerization. Finally, we will very briefly mention some interesting methods that make use of interface-driven templating for making well-defined assembled clusters and supracolloidal structures

Future innovation in process system engineering

International audienc

Future innovation in process system engineering

International audienc

Optimisation of polymer processes

International audienc