15-10-2020 дата публикации
Номер: US20200325251A1
Принадлежит:
Provided is a collection of polymeric beads, wherein the beads comprise 1. A collection of polymeric beads , wherein the beads comprise(i) 75 to 99% by weight, based on the weight of the bead, polymerized units of monofunctional vinyl monomer, and wherein, within each bead, the average concentration of moles of polymerized units of multifunctional vinyl monomer per cubic micrometer is MVAV;', 'wherein, within each bead, T1000 is a sequence of 1,000 unique connected polymerized monomer units;', 'wherein, within each T1000, MVSEQ is the weight percent polymerized units of multifunctional vinyl monomer, based on the weight of T1000;', 'wherein MVRATIO=MVSEQ/MVAV;', 'and', 'wherein 90% or more of the beads by volume are uniform beads, wherein a uniform bead is a bead in which 90% or more of all T1000 sequences has MVRATIO of 1.5 or less., '(ii) 1 to 25% by weight, based on the weight of the bead, polymerized units of multifunctional vinyl monomer;'}2. The collection of polymeric beads of claim 1 , wherein claim 1 , in 90% or more of the beads by volume claim 1 , 90% or more of all T1000 sequences has MVRATIO of 1.25 or less.3. The collection of polymeric beads of claim 1 , wherein the monofunctional monomer comprises styrene.4. The collection of polymeric beads of claim 1 , wherein the multifunctional monomer comprises divinylbenzene.5. The collection of polymeric beads of claim 1 , wherein 35% or less of the T1000 sequences have MVRATIO of 0.5 or less. A useful method of producing polymeric beads is suspension polymerization, which is a process in which monomer droplets are suspended in an aqueous medium and then the monomer in the droplets is polymerized to form polymeric beads. When a mixture of monomers is present in the monomer droplet, it is known that the monomers usually react at different rates, thus forming an inhomogeneous polymeric bead. For example, it is contemplated that one or more regions within the droplet may form copolymer that has a proportion of ...
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