Precipitation Polymerization in Acetic Acid: Study of the Solvent Effect on the Morphology of Poly(divinylbenzene)
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- 作者：Qing Yan ; Tongyang Zhao ; Yaowen Bai ; Fen Zhang ; Wantai Yang*
- 刊名：Journal of Physical Chemistry B
- 出版年：2009
- 出版时间：March 12, 2009
- 年：2009
- 卷：113
- 期：10
- 页码：3008-3014
- 全文大小：394K
- 年卷期：v.113,no.10(March 12, 2009)
- ISSN：1520-5207
文摘
This paper reports on two important results regarding the precipitation polymerization of poly(divinylbenzene) (PDVB) in acetic acid (HAc). (1) Acetic acid is a novel kind of solvent worthy of investigation because it is amphipathic and innoxious. Thus, two kinds of model solvents, methyl ethyl ketone (MEK) and n-heptane, were selected to investigate the solvent effect on the particle morphology of PDVB-55 during precipitation polymerization in acetic acid. Monodisperse PDVB-55 microspheres were obtained with an MEK content of 30 vol % and a DVB loading of 2 vol %. Odd-shaped particles were found to almost disappear when MEK was added. For MEK contents up to 90 vol %, space-filling macrogels consisting of small particles with diameters of around 10 nm were obtained. More homocoagulated particles were produced when n-heptane was added, for which concentrations up to 50 vol % gave rise to cauliflower-like particles. Thus, in the acetic acid system, microspheres, pumpkin-like particles, macrogels, and coagulum could be successfully obtained. (2) The preparation of nonpolar PDVB-55 particles could be more predictable. For the first timebased on the regulation of former studiesthe regularity of the dispersive term (δd) on the particle morphology for a PDVB precipitation polymerization system was reported. The three-dimensional Hansen solubility parameters were utilized to perfect the regularity of the Hildebrand solubility parameter. Microspheres or particles were formed in the range of moderate δ values for both parameters, i.e., δ = 20.2−24.3 MPa1/2 or δ = 16 MPa1/2. What was even more important, δd was found to be around 15.4 MPa1/2, and δh should be below 13.5 MPa1/2. Cyclohexane, cyclohexanone, n-butyl acetate, and 1,4-dioxane were used to verify this regularity, and positive results were obtained. Stable, uniform, and well-separated PDVB-55 microspheres and particles were produced as a result of interaction forces between oligomers, polymers, and solvent.