title: Preparation of Polyamide-6 Submicrometer-Sized Spheres by In Situ Polymerization.
abstract: Polyamide-6 (PA6) submicron-sized spheres are prepared by two steps: (1) anionic ring-opening polymerization of ε-caprolactam in the presence of poly(ethylene glycol)-block-poly-(propylene glycol)-block-poly(ethylene glycol)(PEG-b-PPG-b-PEG) and (2) separation of PA6 spheres by dissolving PEG-b-PPG-b-PEG from the prepared blends. The PA6 microspheres obtained are regular spherical, with diameter ranging from 200 nm to 2 μm and narrow size distribution, as confirmed by scanning electron microscopy. By comparison with PA6/PS and PA6/PEG systems, it is denominated that the PEG blocks in PEG-b-PPG-b-PEG can effectively reduce the surface tension of PA6 droplets and further decrease the diameter of the PA6 microspheres. The PPG block in PEG-b-PPG-b-PEG can prevent the PA6 droplets coalescing with each other, and isolated spherical particles can be obtained finally. The phase inversion of the PA6/PEG-b-PPG-b-PEG blends occurs at very low PEG-b-PPG-b-PEG content; the PEG-b-PPG-b-PEG phase can be removed by water easily. The whole experiment can be finished in a short time (approximately in half an hour) without using any organic solvents; it is an efficient strategy for the preparation of submicron-sized PA6 microspheres.
authors: Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, 310027, China.
authors: Xingke
authors: X
authors: Zhao
authors: Shanghai Genius Advanced Materials Co., Ltd, Shanghai, 201109, China.
authors: Housheng
authors: H
authors: Xia
authors: School of Chemistry and Chemical Engineering, Heifei University of Technology, Heifei, 230009, China.
authors: Xubing
authors: X
authors: Fu
authors: Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, 310027, China.
authors: Jianping
authors: J
authors: Duan
authors: Shanghai Genius Advanced Materials Co., Ltd, Shanghai, 201109, China.
authors: Guisheng
authors: G
authors: Yang
mesh_terms: D002209:Caprolactam / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry*; D055772:Green Chemistry Technology; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D009757:Nylons / Q000138:chemical synthesis*; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry*; D058105:Polymerization; D011108:Polymers / Q000138:chemical synthesis*; D011409:Propylene Glycols / Q000737:chemistry*; D013500:Surface Tension
chemical_list: D009757:Nylons; D011108:Polymers; D011409:Propylene Glycols; C528875:poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) copolymer; C009916:nylon 6; D011092:Polyethylene Glycols; D002209:Caprolactam
keywords: microspheres; phase separation; polyamide-6; ring-opening anionic polymerization