苯乙烯(St)单体、过硫酸钾(KPS)和二乙烯基苯(DVB)通过无皂乳液聚合,在70℃下反应8 h,合成聚苯乙烯(PS)纳米粒子,PS磺化,得到磺化聚苯乙烯(SPS),通过正庚烷和乙醇溶胀后,水进入粒子内部发生相分离,形成多孔聚苯乙烯PS,在-30 k Pa负压条件下,负载缓蚀剂苯丙三氮唑(BTA)。考察单体量和反应时间对粒子形态的影响。结果表明,采用10 g St,0.05 g KPS,100 mL去离子水,反应2 h后加入0.05 g DVB,可以得到粒径合适、球形完整的PS纳米微球。PS微球磺化6 h,n(乙醇)∶n(水)∶n(正庚烷)=5∶5∶1,造孔10 h时,可得到形貌和孔径合适的多孔SPS纳米微球。SEM、TEM和FTIR表明,多孔SPS微球表面和内部负载上了一定量的缓蚀剂BTA。 相似文献
苯乙烯(St)单体、过硫酸钾(KPS)和二乙烯基苯(DVB)通过无皂乳液聚合,在70℃下反应8 h,合成聚苯乙烯(PS)纳米粒子,PS磺化,得到磺化聚苯乙烯(SPS),通过正庚烷和乙醇溶胀后,水进入粒子内部发生相分离,形成多孔聚苯乙烯PS,在-30 k Pa负压条件下,负载缓蚀剂苯丙三氮唑(BTA)。考察单体量和反应时间对粒子形态的影响。结果表明,采用10 g St,0.05 g KPS,100 mL去离子水,反应2 h后加入0.05 g DVB,可以得到粒径合适、球形完整的PS纳米微球。PS微球磺化6 h,n(乙醇)∶n(水)∶n(正庚烷)=5∶5∶1,造孔10 h时,可得到形貌和孔径合适的多孔SPS纳米微球。SEM、TEM和FTIR表明,多孔SPS微球表面和内部负载上了一定量的缓蚀剂BTA。 相似文献
Nanoparticls of multifunctional polymers have very promising characteristics that make this type of the polymers have rapidly growing research attentions and innovations due to advantageous high surface area to volume ratio. In this study, poly (Styrene-co-Methacrylic acid) (P)St-co-MAA)) copolymer nanoparticles were synthesized using free radical polymerization method. Copolymerization takes place via a precipitation polymerization technique. Different polymerization factors such as co-monomer concentration and ratio, polymerization temperatures, polymerization time, initiator concentration and solvent composition were studied to obtain the copolymerization conditions that produce the maximum copolymerization conversion yield and the minimum particle size in nanosize range in a very narrow size distribution. The P)St-co-MAA) copolymer nanoparticles were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and Thermogravimetric analysis (TGA). When the copolymerization occurred at a monomer ratio of MAA: St (90:10) we obtained the smallest particle size of 25 nm. The maximum conversion yield reached to 99.5% within 4 h of polymerization in the case of St: MAA (1:1) comonomer ratio and 10% total monomer ratio using water:ethanol (1:1) mixture as a co-solvent system. The results clearly demonstrated that use of water as a co-solvent is indeed very effective to promote the polymerization to high conversion. The MAA content in copolymer composition was investigated by carboxylic content via titration method and also by FTIR.
N-doped carbon coated TiO2 microspheres (CNx/TiO2) were synthesized by the carbonization of the polypyrrole (PPy) coating on the surface of TiO2 microspheres and used as support to disperse Pt and PtCo nanoparticles for investing the selective hydrogenation of cinnamaldehyde. The support and catalysts have been characterized in terms of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS). The hydrogenation results showed the conversion increased with an increase of CNx amount until the CNx coated TiO2 microspheres completely. 相似文献
A pH-responsive copolymer hydrogel was synthesized based on methyl methacrylate (MMA) and methacrylic acid (MAA) as monomers, and was adopted as a nanoreactor for assembling Ag nanoparticles. Fourier transform infrared spectroscope (FTIR), scanning electron microscopy (SEM), transmission electron microscope (TEM), UV-visible spectroscopy (UV-Vis) and thermogravimetric analysis (TGA) were used to fully characterize the formation of silver nanoparticles in P(MMA-co-MAA) hydrogels. The experimental results showed that the P(MMA-co-MAA) hydrogels assume a three-networks architecture in morphologies, and that nearly spherical Ag nanoparticles are formed in these hydrogel networks; the size of these Ag nanoparticles varies with the system composition. The swelling kinetics investigations demonstrated that the equilibrium swelling ratio (ESR) of the P(MMA-co-MAA)/Ag hydrogels depended on the content of the MAA and pH of the buffer solutions, and the ESR values were reduced with increasing MAA contents. The antibacterial properties against both S. aureus and B. subtilis bacteria demonstrated that the P(MMA-co-MAA)/silver nanocomposite hydrogels had higher antimicrobial efficacy than the pure P(MMA-co-MAA) counterparts. Therefore, the nanocomposite hydrogels turned out to be a potentially smart material in the range of applications of antibacterial activity. 相似文献
The surface of waste rubber powder (WRP) was graft-modified with styrene (St) by bulk polymerization method. The effects of
styrene content, initiator mass, time of reaction, and temperature on the graft efficiency were investigated. The results
showed that the graft efficiency (%) was highest when 89 wt% styrene and 0.11 g of initiator were added for reaction time
of 25 h at 85 °C. The surface of graft-modified rubber powder was characterized by Fourier transform infrared spectroscopy
(FTIR), scanning electron microscope (SEM), energy dispersive X-ray (EDXS) analysis, and thermogravimetric (TG/DTG) analysis.
The results showed that polystyrene (PS) was grafted onto waste rubber powder, which formed a WRP/PS core–shell structure. 相似文献