1. “Microparticles are particles between 0.1 and 100 m in size. Commercially available microparticles are available in a wide variety of materials, including ceramics, glass, polymers, and metals. Microparticles encountered in daily life include pollen, sand, dust, flour, and powdered sugar.
Microparticles have a much larger surface-to-volume ratio than at the macroscale, and thus their behavior can be quite different. For example, metal microparticles can be explosive in air.
Microspheres are spherical microparticles, and are used where consistent and predictable particle surface area is important.
In biological systems, microparticles are small membrane bound vesicles circulating in the blood derived from cells that are in contact with the bloodstram such as platelets and endothelial cells (see endothelial microparticle). Because they retain the signature membrane protein composition of the parent cell, microparticles carry useful information and can be detected and characterized by flow cytometry.”
(Microparticles, Wikipedia, 8/3/2013)
2. US Patent 8,871,844 (October 28, 2014), “Composite Particles having Organic and Inorganic Domains,” Abdulmajid Hashemzadeh (Wacker Chemie AG, Munich, Germany)
Composite particles consisting inorganic /organic components are useful for a variety of reasons including additive compounding, Simple agglomeration leads to inadequate storage stability resulting in gelation or speck formation. This can be avoided by chemically coupling the domains.
Hashemzadeh of Wacker Chemical, Germany, coupled the two different domains by mixing inorganic oxides (oxide particles), <1000 nm, polymers and coupling reagents. The polymers contain more than 4.9 wt% ethylenically unsaturated carboxylic acids such as the vinyl esters of carboxylic acids and the coupling agents are alkylalkoxysilanes. The final particles are 20 to 1000 nm with 2 to 500 nm inorganic domains. The components are dispersed in a liquid and mixed at 30 to 100 C and neutralized to complete the reaction,8,871,844 (10/28/2014)
1. Uniform Microparticles
U.S. Patent 8,470,398 (June 25, 2013), “Method for Producing Single-Hole Hollow Polymer Microparticles,” Hiroshi Yamauchi, and Yasuyuki Yamada (Sekisui Chemical Co., Ltd., Osaka, Japan).
Microparticles on the order of microns are useful for lightweight structures, heat insulation, cushioning, and selective light absorption. However, these applications require very uniform microparticle sizes. Preparation by suspension polymerization is commonly used to prepare microparticles but adequate uniformity is difficult requiring elaborate classification processing. Yamauchi and Yamada produced single-hole hollow polymer particles with extremely uniform dimensions without need for special classification operations. A dispersion of swollen particles is prepared by mixing seed particles in water with an oil-soluble solvent. The seed particles absorb the oil-soluble solvent. A water soluble polymer and crosslinkable monomer is added to the suspension and precipitated onto the suspended swollen particles. The particles after curing are washed with water and the oil soluble solvent vaporized, The inner and outer diameters are extremely uniform. Particles with outer diameters range from 0.1 to 100 microns while the inner diameters range from 10 to 99% of the outer diameters.
For earlier Patent Titles, go to Sorted Patents /Powders /Microparticles.
System and method for testing of micro-sized materials
Processes for coating a carrier with microparticles
Micron size powders having nano size reinforcement
Controlled release microparticles
Bonding material using metal nanoparticles coated with C6-C8 fatty acids, and bonding method
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Roger D. Corneliussen
Maro Polymer Links
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Copyright 2013 by Roger D. Corneliussen.
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* Date of latest addition; date of first entry is 8/3/2013.