Showing papers by "Robert Pfeffer published in 2004"

Polymer coating/encapsulation of nanoparticles using a supercritical antisolvent process

Abstract: A process, method and/or system for preparing polymer-coated nanoparticles and/or other ultrafine particles utilizing a supercritical fluid, e.g., supercritical carbon dioxide (SC CO2), as an antisolvent that may be added to a solution of a polymer and an organic solvent in which insoluble nanoparticles or the like are suspended. The coating process occurs when the supercritical fluid (e.g., SC CO2) and the nanoparticle-containing suspension are combined to cause the suspended nanoparticles to precipitate as coated nanoparticles. Processing parameters for optimizing and/or enhancing the efficacy and/or efficiency of the coating process, method and/or system and for controlling the coating and/or agglomeration of coated particles are also described. The process, method and/or system has wide ranging applicability, e.g., for coating and/or encapsulation of pharmaceuticals, cosmetics, food products, chemicals, agrochemicals, pesticides, polymers, coatings, catalysts and the like.

System and method for nanoparticle and nanoagglomerate fluidization

Abstract: With the coupling of an external field and aeration (or a flow of another gas), nanoparticles can be smoothly and vigorously fluidized. A magnetic force and/or pre-treatment may be employed with the fluidizing gas and, when coupled with a fluidizing medium, provide excellent means for achieving homogenous nanofluidization. The magnetic force interacts with non-fluidizing magnetic particles and helps to break channels as well as provide enough energy to disrupt the strong interparticle forces, thereby establishing an advantageous agglomerate size distribution. Enhanced fluidization is reflected by improved performance-related attributes. The fluidized nanoparticles may be coated, surface-treated and/or surface-modified in the fluidized state. In addition, the fluidized nanoparticles may participate in a reaction, either as a reactant or a catalyst, while in the fluidized state.

Ordered particle structures and methods of making same

Abstract: Techniques and methods of formation of ordered mixtures of particles by 'clustering'. Clustering comprises local 'structuring' consisting of a large 'host' and smaller 'guest' particles by various techniques. Small amounts of polymer are coated onto solid particles by various means. In one embodiment, an ordered mixture is created wherein the material that is of lesser quantity is of small particle size (the 'B' particles) and the 'A' particles are of larger size, The 'B' particles are then coated onto a single A particle. By creating this ordered structure, each composite particle has the proper or stoichiometric amount of all ingredients. This dry composite material produced is appropriately used in various applications such as pharmaceutical formulations in the form of tablets, capsules, oral suspensions, inhalant, parental formulations and the like; energetics manufacture such as but not limited to explosives, propellants and pyrotechnics; agricultural products including but not limited to fertilizers, herbicides and pesticides; nutritional supplements and the like.

Netshape manufacturing processes and compositions

Abstract: Techniques and processes that combine particulate coating processes with particulate handling steps resulting in the formation of free-flowing particulates for introduction into energetic product vessels to affect an in-situ, net-shape manufactured product. The processes involve selecting suitably sized materials, processing such materials such that they are surface-coated and/or locally “structured” particulates, and pouring, preferably “dry” pouring, these processed materials into an energetic product vessel and infusing the filled vessel with a polymerizable and surface-compatible monomer or oligomer which flows into the unoccupied volume, followed by polymerization of the monomer, which then becomes the binder giving mechanical integrity to the final, net-shape energetic composition.

Revetement/enrobage de nanoparticules au moyen de polymeres par un procede par antisolvant supercritique

Abstract: L'invention concerne un procede, une methode et/ou un systeme pour preparer des nanoparticules et/ou d'autres particules ultrafines a revetement polymere au moyen d'un fluide supercritique, p. ex. du dioxyde de carbone supercritique (CO2 SC), utilise comme antisolvant pouvant etre ajoute a une solution d'un polymere et d'un solvant organique contenant des nanoparticules insolubles ou similaire en suspension. Le procede de revetement consiste a combiner le fluide supercritique (p. ex. le CO2 SC) et la suspension contenant des nanoparticules de sorte que les nanoparticules en suspension se precipitent sous forme de nanoparticules revetues. L'invention concerne egalement des parametres de procede permettant d'optimiser et/ou d'accroitre l'efficacite et/ou le rendement du procede, de la methode et/ou du systeme de revetement et de controler le revetement et/ou l'agglomeration des particules revetues. Le procede, la methode et/ou le systeme selon l'invention presentent de nombreuses possibilites d'application, p. ex. des applications de revetement et/ou d'enrobage dans le domaine des produits pharmaceutiques, cosmetiques, alimentaires, chimiques ou agrochimiques, des pesticides, polymeres, revetements, catalyseurs et similaires.