在水存在下的乳液和悬浮聚合已广泛用于 PVDF 及其共聚物的实验室和工业生产。通过使用水溶性引发剂,例如过硫酸铵或2,2'-偶氮二异丁脒盐酸盐,在水中引发悬浮聚合。氧化还原引发剂,如海外npv加速器试用-焦亚硫酸钠或过硫酸铵-亚硫酸钠等也已被采用。较高的压力有利于快速聚合、增加分子量和提高引发剂的效率。在乳液聚合中,全氟羧酸或全氟烷基丙胺的阳离子表面活性剂用作乳化剂。种子乳液聚合可产生 Junas 胶乳纳米粒子,其中交联的胶乳粒子被可混溶的单体溶胀,然后进行聚合。
Emulsion and suspension polymerization in the presence of water have been widely used in the laboratory and industrial production of PVDF and its copolymers. Suspension polymerization is initiated in water by using a water-soluble initiator, such as ammonium persulfate or 2,2 '- azodiisobutymidine hydrochloride. Redox initiators, such as potassium persulfate sodium pyrosulfite or ammonium persulfate sodium sulfite, have also been used. Higher pressure is conducive to rapid polymerization, increase molecular weight and improve the efficiency of initiator. In emulsion polymerization, perfluorocarboxylic acid or perfluoroalkyl propyl amine cationic surfactants are used as emulsifiers. Seed latex polymerization can produce Junas latex nanoparticles, wherein the cross-linked latex particles are first swollen by miscible monomers and then polymerized.
反应挤压
Reactive extrusion
淀粉和聚(丙烯酰胺)的混合物
Mixture of starch and poly (acrylamide)
淀粉-聚(丙烯酰胺)共聚物已通过与过硫酸铵反应挤出制备的挤出温度对丙烯酰胺的转换没有显著影响。
Starch poly (acrylamide) copolymer has been prepared by reactive extrusion with ammonium persulfate. The extrusion temperature has no significant effect on the conversion of acrylamide.
对于各种底物的接枝,过硫酸铵、硝酸铈铵或硫酸亚铁铵/过氧化氢可用作引发剂。
For the grafting of various substrates, ammonium persulfate, ammonium ceric nitrate or ammonium ferrous sulfate / hydrogen peroxide can be used as initiators.
当单体与淀粉的比例高时,获得更多更高分子量的接枝。低水分含量导致较高分子量的接枝较少。
When the ratio of monomer to starch is high, more grafting with higher molecular weight can be obtained. Low moisture content leads to less grafting with higher molecular weight.
使用含有 23%直链淀粉的未改性和阳离子马齿淀粉和含有 2% 直链淀粉的蜡质玉米淀粉检测了阳离子淀粉改性的效。与未改性淀粉相比,阳离子淀粉接枝共聚物通常具有较低的分子量,但直链淀粉的含量没有显着影响。
The modification effect of cationic starch was tested by using unmodified and cationic horsetooth starch containing 23% amylose and waxy corn starch containing 2% amylose. Compared with unmodified starch, cationic starch graft copolymers usually have lower molecular weight, but the content of amylose has no significant effect.
淀粉的阳离子改性增强了接枝位点的形成。通过这种方式,可以定制淀粉改性的聚(丙烯酰胺)共聚物的性能。
Cationic modification of starch enhanced the formation of graft sites. In this way, the properties of starch modified poly (acrylamide) copolymers can be customized.
过硫酸铵
Ammonium persulfate
含氟聚合物的制备、结构与性能
Preparation, structure and properties of fluoropolymers
异相合成
Heterogeneous synthesis
在水存在下的乳液和悬浮聚合已广泛用于 PVDF 及其共聚物的实验室和工业生产。通过使用水溶性引发剂,例如过硫酸铵或2,2'-偶氮二异丁脒盐酸盐,在水中引发悬浮聚合。氧化还原引发剂,如海外npv加速器试用-焦亚硫酸钠或过硫酸铵-亚硫酸钠等也已被采用。较高的压力有利于快速聚合、增加分子量和提高引发剂的效率。在乳液聚合中,全氟羧酸或全氟烷基丙胺的阳离子表面活性剂用作乳化剂。种子乳液聚合可产生 Junas 胶乳纳米粒子,其中交联的胶乳粒子被可混溶的单体溶胀,然后进行聚合[3]。
Emulsion and suspension polymerization in the presence of water have been widely used in the laboratory and industrial production of PVDF and its copolymers. Suspension polymerization is initiated in water by using a water-soluble initiator, such as ammonium persulfate or 2,2 '- azodiisobutymidine hydrochloride. Redox initiators, such as potassium persulfate sodium pyrosulfite or ammonium persulfate sodium sulfite, have also been used. Higher pressure is conducive to rapid polymerization, increase molecular weight and improve the efficiency of initiator. In emulsion polymerization, perfluorocarboxylic acid or perfluoroalkyl propyl amine cationic surfactants are used as emulsifiers. Seeded emulsion polymerization can produce Junas latex nanoparticles, wherein the cross-linked latex particles are first swollen by miscible monomers and then polymerized [3].