Temperature-Sensitive Flocculants Based on Poly(N-isopropylacrylamide-co-diallyldimethylammonium Chloride)

✍ Scribed by Yulin Deng; Huining Xiao; Robert Pelton

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 118 KB
• Volume: 179
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1996.0201

✦ Synopsis

linear ones. Another example of an innovation coming from

The flocculation of aqueous colloidal TiO 2 , average diameter the paper industry is the use of microparticle flocculant sys-266 nm, with a cationic copolymer of N-isopropylacrylamide and tems (5). In this technology, flocculation is induced by the diallyldimethylammonium chloride (2.2 mol%) was faster over a sequential addition of a charged polymer followed by an broader range of copolymer concentrations at 42ЊC than at 23ЊC. oppositely charged suspension of colloidal particles. Exam-At room temperature the copolymer formed a solution, whereas ples of microparticle flocculant systems include high-molecat 42ЊC the polymer was present as cationic colloidal particles ular-weight polyacrylamide followed by bentonite, cationic with an average diameter of 87 nm. Both physical forms of the starch plus colloidal silica, and colloidal aluminum hydroxcopolymer adsorbed/deposited onto TiO 2 at pH 7 due to favorable ide plus cationic starch (6-10).

electrostatic interactions. Reversible temperature-sensitive flocculation was observed at intermediate copolymer concentrations. At

Interesting systems related to conventional flocculants are room temperature the copolymer concentration was high enough cationic copolymers of N-isopropylacrylamide (NIPAM) to sterically stabilize the TiO 2 whereas flocculation occurred at described in a patent by Guillet et al. (11). Cationic copoly-42ЊC when the copolymer was present as cationic colloidal partimers of NIPAM, like poly(N-isopropylacrylamide) homocles.