Novel one-step route for synthesizing sub-micrometer PSt hollow spheres via redox interfacial-initiated method in inversed emulsion

Interfacial-initiated polymerization of styrene (St) was carried out in inversed emulsion with cumene hydroperoxide (CHPO) and ferrous sulfate (FeSO₄)/disodium ethylenediaminetetraacetate (NaEDTA)/sodium formaldehyde sulfoxylate (SFS) as the redox initiation system. The water-soluble Fe²⁺-NaEDTA-SFS acted as the reducing component and the oil-soluble CHPO as the oxidant component of the redox initiation system. Therefore, the primary radicals were produced mainly at the oil/water interface to initiate the polymerization of St. Thus, sub-micrometer hollow polystyrene (PSt) spheres were obtained by one-stage polymerization, which was supported by the techniques of transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM).     

Studies on chitin 3—effect of coagulants and annealing on the preparation and the properties of chitin membrane

Chitin membrane was prepared by casting a N,N-dimethyl acetamide, N-methyl 2-pyrrolidone and lithium chloride (DMA-NMP-LiCl)solution of chitin and coagulating with several media. The effect of the coagulants on membrane formation was studied. 2-Propanol was found to be more favourable than methanol, ethanol, acetone and mixtures of 2-propanol and water. The membrane obtained in 2-propanol was subjected to annealing. Annealing made the membrane dense and strong. The tensile strength of the membrane annealed at 145°C for 2hr was about twice that of an unannealed membrane. The solute permeability of the annealed membranes was lower than that of the original one. These phenomena could be clearly interpreted in terms of crystallinity.     

甲壳素纤维/毛/绒双层织物的设计

通过分析甲壳素纤维各项性能,将其引入山羊绒产品中,对双层织物的设计进行探讨,并经过纺纱和织物试制,提出了设计与生产中应注意的问题,开发出了具有永久抗菌性的表层为羊绒、里层为甲壳素与改性羊毛混纺的系列产品.     

酸、碱溶液对脱脂蚕蛹的解剖结构影响

将脱脂蚕蛹分别置于清水、1%盐酸溶液和1%氢氧化钠溶液中,100℃浸泡处理20 min,采用电子光学显微分析技术观察脱脂蚕蛹的解剖结构。结果表明:①清水浸泡,蛋白质、甲壳素膨胀;②盐酸溶液浸泡,在蛋白质、甲壳素膨胀的同时,有蛋白的部分分解;③氢氧化钠溶液浸泡,蛋白质、甲壳素膨胀,蛋白质溶解,并伴有部分蛋白的分解。碱对蛋白层与甲壳层的层间有劈开作用。碱液能实现蛋白层与甲壳层的剥离。     

石蜡聚苯乙烯微球的制备

通过悬浮聚合技术合成了石蜡聚苯乙烯微球，研究了合成过程中引发剂浓度及交联剂用量对微球粒径及其分布的影响。     

Preparation of DNA-encapsulated polyethersulfone hollow microspheres for organic compounds and heavy metal ions removal

DNA-encapsulated polyethersulfone (PES) hollow microspheres are fabricated by means of a liquid-liquid phase separation technique; the hollow microspheres are then used to remove environmental pollutant organic compounds and heavy metal ions. The amounts of DNA encapsulated in the microspheres are dependent on the PES concentration, the DNA concentration used to prepare the particles, and the diameter of the syringe needle. The hollow microspheres can be used to remove harmful organic compounds including ethidium bromide (EB), acridine orange (AO) and endocrine disruptors. With the increase of the DNA amount encapsulated into the hollow microspheres, the removal ratios of these compounds increased. Additionally, the DNA-encapsulated PES hollow microspheres can selectively accumulate and remove heavy metal ions such as Ag⁺, Cu²⁺ and Zn²⁺ These results suggested that the DNA-encapsulated PES hollow microspheres have a potential to be used in environmental applications.     

绿色木霉合成几丁质酶条件的研究

绿色木霉ＺＵ０１１在以０．５％几丁质为唯一碳源的培养基中几丁质酶活达到０．１２４ＩＵ／ｍＬ。几丁质酶合成的最佳碳源和诱导物为几丁质。在一定范围内啬２基中几丁质浓度,葡萄糖浓度,微量元素盐浓度和碳氮比都能提高几丁质酶活。胆汁酸和吐温８０作为表面活性剂能显著提高几丁质酶活。     

Synthesis and characterization of modified chitosan microspheres: Effect of the grafting ratio on the controlled release of nifedipine through microspheres

The grafting of acrylamide onto a chitosan backbone was carried out at three acrylamide concentrations (polymer/monomer ratio = 1:1, 1:2, and 1:3). The synthesis of the grafted polymer was achieved by K₂S₂O₈‐induced free‐radical polymerization. Microspheres of polyacrylamide‐g‐chitosan crosslinked with glutaraldehyde were prepared to encapsulate nifedipine (NFD), a calcium channel blocker and an antihypertensive drug. The microspheres of polyacrylamide‐g‐chitosan were produced by a water‐in‐oil emulsion technique with three different concentrations of glutaraldehyde as the crosslinking agent. Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) were used to characterize the grafted copolymers, and the microspheres were prepared from them. FTIR and DSC were also used to analyze the extent of crosslinking. The microspheres were characterized by the particle size; the water transport into these microspheres, as well as the equilibrium water uptake, were studied. Scanning electron microscopy confirmed the spherical nature of the particles, which had a mean particle size of 450 μm. Individual particle dynamic swelling experiments suggested that with an increase in crosslinking, the transport became case II. The release of NFD depended on the crosslinking of the network and on the amount of drug loading. Calculating the drug diffusion coefficients with the initial time and later time approximation method further supported this. The drug release in all 27 formulations followed case II transport, and this suggested that the time dependence of the NFD release followed zero‐order kinetics. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2940–2949, 2003     

Preparation of superparamagnetic immunomicrospheres and application for antibody purification

A novel and effective protocol for the preparation of superparamagnetic immunomicrospheres has been developed. First, micro‐size magnetic poly (methacrylate‐divinylbenzene) (PMA‐DVB) spheres were prepared by a modified suspension polymerization method. The oleic acid coated magnetite (Fe₃O₄) nanoparticles made by coprecipitation were mixed with monomers of MA, DVB, and initiator benzoyl peroxide (BPO) to form oil in water emulsion droplets with the presence of poly (vinyl alcohol) (PVA‐1788) as a stabilizer. The polymerization reaction was carried out in a 2‐L beaker equipped with four vertical stainless steel baffleplates by increasing the temperature of the mixture at a controlled rate. The resulting magnetic microspheres are micro‐sized (less than 8μm in diameter) and 80 percent of them are in the size ranging from 1 to 5 μm. Then, they were highly functionalized via ammonolysis reaction with ethylenediamine, and the surface amino‐modified magnetic microspheres were obtained. The morphology and properties of these magnetic microspheres were examined by SEM, TEM, VSM, and FT‐IR. Affinity ligand protein A (ProtA) was covalently immobilized to the amino‐modified magnetic microspheres by the glutaraldehyde method. These ProtA‐immobilized magnetic immunomicrospheres were effective for affinity bioseparation processes, as was demonstrated by the efficient immunoaffinity purification of antibodies IgG2a (22mg per gram of microspheres) from mouse ascites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2205–2211, 2004     

BaFe12O19/聚氨酯磁性复合微球的制备和表征

通过BaFe12O19硅烷偶联剂改性,聚乙二醇1000、甲苯二异氰酸酯在二甲苯溶液中预聚合,预聚物溶液在分散剂聚乙烯吡咯烷酮K30的水溶液中悬浮聚合,三步合成了BaFe12O19/聚氨酯复合微球.用扫描电镜、红外光谱仪、热重-差示扫描同步热分析仪和振动样品磁强计对微球的形貌、结构、玻璃化温度(Tg)和磁性能进行了表征.结果表明:合成的微球以BaFe12O19颗粒为核聚氨酯为壳.表面分布有微孔,微球粒径在400μm左右,粒径大小可通过控制反应条件调节.微球中磁性物质BaFe12O19的含量为11.11%(质量分数),Tg在290 ℃左右,耐热性能好,微球的饱和磁化强度为3.36×103 A/m,矫顽力为3.06×104 A/m.该复合微球是一种有潜在应用价值的新型血管内栓塞材料.