Department of Chemistry, Oklahoma State University, Stillwater, OK 74078, USA; Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843, USA(1).
Department of Chemistry, Oklahoma State University, Stillwater, OK 74078, USA.
J Colloid Interface Sci. 2017 Oct 15;504:111-114. doi: 10.1016/j.jcis.2017.05.030. Epub 2017 May 12.
Surfactant-catalyzed room-temperature radical polymerization of methyl methacrylate (MMA) was conducted in the presence of fumed silica nanoparticles and water. Three types of surfactants, cationic (CTAB), nonionic (Triton X-100) or anionic (SDS), were used to catalyze the decomposition of the initiator, 2,2'-azobisisobutyronitrile (AIBN). The surfactant-catalyzed decomposition rate constant for AIBN at room temperature was found to be independent of the surfactant type. However, the rates of polymerization of the MMA emulsion gels at room temperature were found to depend on the types of surfactant with: cationic>nonionic>anionic. An inhibition period was observed for the polymerizations with nonionic and anionic surfactants. The radical-inhibition was likely due to the reactions between the radicals and the silanol groups on fumed silica. This inhibition can be reduced by using cationic surfactants to block these surface silanols.
在气相二氧化硅纳米粒子和水的存在下，进行了甲基丙烯酸甲酯（MMA）的表面活性剂催化室温自由基聚合。使用了三种类型的表面活性剂，阳离子（CTAB）、非离子（Triton X-100）或阴离子（SDS），来催化引发剂 2,2'-偶氮二异丁腈（AIBN）的分解。在室温下，AIBN 的表面活性剂催化分解速率常数与表面活性剂类型无关。然而，在室温下 MMA 乳液凝胶的聚合速率取决于表面活性剂的类型：阳离子>非离子>阴离子。非离子和阴离子表面活性剂的聚合存在抑制期。自由基抑制可能是由于自由基和气相二氧化硅上的硅醇基团之间的反应所致。通过使用阳离子表面活性剂来封闭这些表面硅醇，可以减少这种抑制。
