Preparation of Polyamide‐6 Submicrometer‐Sized Spheres by In Situ Polymerization. Issue 22 (22nd August 2015)

• Record Type: Journal Article
• Authors: Zhao, Xingke; Xia, Housheng; Fu, Xubing; Duan, Jianping; Yang, Guisheng
• Is Part Of: Macromolecular rapid communications. Volume 36:Issue 22(2015:Nov.)
• Page Start: 1994
• Page End: 1999
• Publication Date: 2015-08-22
• Subjects: microspheres -- phase separation -- polyamide‐6 -- ring‐opening anionic polymerization; Macromolecules -- Periodicals; Polymers -- Periodicals; Chemistry -- Periodicals; 547.705
• DOI: 10.1002/marc.201500358
• Languages: English
• ISSNs: 1022-1336

Abstract

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. Abstract : Submicrometer‐sized polyamide‐6 micro­spheres are synthesized for the first time by reaction‐induced phase separation of PA6/PEG‐ b ‐PPG‐ b ‐PEG blends. The resulting PA6 microspheres show regular spherical shapes, with diameters ranging from 200 nm to 2 μm. The PEG block effectively reduces the surface tension of the PA6 droplets, further decreasing the microsphere diameter; the PPG block prevents the droplets coalescing, leading to the isolation of spherical PA6 microspheres.