采用一种简单易行的方法制备了氨基功能化的聚苯乙烯纳米粒子.首先,采用4.乙烯基苄氯与1,3-丙二胺置换反应制备了含有氨基功能基团的可聚合单体N-(3-氨基丙基)对乙烯基苄基亚胺(CVPD).然后,采用乳液聚合,以苯乙烯(St)和CVPD为共聚单体,水溶性的4-(2-羟乙氧基)苯基-(2-羟基-2-丙基)酮(Irgacure 2959)为光引发剂,十六烷基三甲基溴化铵(CTAB)为乳化剂,经紫外光辐照引发,合成了P(St-co—CVPD)二元共聚物的纳米胶乳.体系的乳化剂用量仅为体系总质量的0.1wt%~0.8wt%,远小于常用来制备纳米粒子的微乳液体系的乳化剂用量.用透射电子显微镜(TEM)和激光粒度分析仪(DLS)表征了P(St—co—CVPD)纳米粒子的粒径和粒径分布.用红外光谱(FTIR)和核磁共振(NMR)证明了P(St-co—CVPD)纳米粒子上氨基的存在,并通过茚三酮显色反应定量检测了氨基含量.分别研究了单体配比,引发剂浓度,乳化剂用量以及紫外光强度对反应体系的影响.实验结果表明,产物粒子尺寸为30~600nm,氨基通过共价键连接在粒子上,其含量为1.2×10^-5~1.6×10^-4mol/g.该乳液体系聚合反应速率较快,单体转化率在60min内即可达到80%.所得粒子的氨基含量可以通过单体配比进行调节.粒子尺寸可通过单体配比,引发剂浓度,乳化剂用量以及紫外光强度进行调节.
Amino-functionalized polystyrene nanoparticles were prepared by a facile approach.First,an amino functionalized monomer N-(3-aminopropyl)-p-vinylbenzylimine(CVPD) was synthesized by the displacement reaction of 4-vinylbenzy chloride and 1,3-propane diamine between dichloromethane.Then the nano-latex of styrene and N-(3-aminopropyl)-p-vinylbenzylimine copolymer were synthesized by UV-induced emulsion polymerization with water-soluble 4-(2-hydroxyethoxy) phenyl-(2-hydroxy-2-propyl) ketone(Irgacure 2959) as the photo-initiator and cetyltrimethylammonium bromides(CTAB) as the surfactant.The surfactant amount is only 0.1 wt% ~ 0.8 wt% of the total system,much lower than that of micoemulsion polymerization system which is generally used to synthesize nanoparticles.The diameter and diameter distribution of the P(St-co-CVPD) nanoparticles were characterized by transmission electron microscopy(TEM) and dynamic light scattering(DLS).The amino groups of the copolymer were evident from Fourier transform infrared spectroscopy(FTIR) and nuclear magnetic resonance(NMR),and the quantity of the amino groups was calculated by ninhydrin reaction.The effects of St /CVPD ratios,initiator concentrations,surfactant concentrations and UV light intensity on the polymerization system were investigated,respectively.The results show that amino-functionalized polystyrene particles with diameters of 30 ~ 600 nm,and amino group contents of 1.2 × 10-5 ~ 1.6 × 10-4 mol /g could be conveniently prepared by this method.The polymerization rate of this emulsion polymerization system is fast,and the monomer conversion can reach 80% within 60 min.The amino group content can be controlled by varying St /CVPD ratios.The particle size can be tuned by changing St /CVPD ratios,initiator concentrations,surfactant concentrations and UV light intensity.