反相微乳聚合制备聚合物纳米粒子

采用正辛烷做连续相,以Span80和Tween60为复合乳化剂,过硫酸铵-亚硫酸氢钠为氧化还原引发剂体系,通过反相微乳聚合制备丙烯酰胺-丙烯酸钠纳米粒子.研究了乳化剂、单体、引发剂配比及用量和温度等因素对聚合的影响.在反应温度为30 ℃,乳化剂浓度为油相质量的12 %～14 %,单体浓度为水相质量的35 %～40 %,引发剂浓度为单体质量的0.05 %～0.07 %时,得到稳定透明的微乳液.经扫描及透射电镜分析,所得共聚物的粒径为40～60 nm之间,粒子均匀分布的规则球形.     

丙烯酰胺聚合物的微乳液制备研究进展

本文对丙烯酰胺反相微乳液聚合体系的组成做了简单介绍,重点总结了不同离子类型的聚丙烯酰胺微乳液的制备方法,并提出了今后AM反相微乳液聚合研究的发展方向。     

丙烯酰胺反相微乳液的制备研究

通过检测乳液电导率,观察其外观、丁达尔现象等方法,研究各种烷烃、乳化体系及单体水相对丙烯酰胺反相微乳液稳定性的影响,得到Isopar M/Span80-Tween60/AM/H2O最优体系微乳液,确定了体系乳化剂用量为18.52%(m/m),最优HLB为8~8.5,最佳单体水溶液浓度50%(m/m),最大水相加入量22.22%(m/m),最佳油水比2.67。     

丙烯酰胺反相微乳液体系的制备、聚合及表征

本论文探讨了用Span80,Tween60为复合乳化剂,煤油为分散介质,制备丙烯酰胺的反相微乳液,并研究了所形成微乳兴的微观结构和影响该微乳液体系聚合反应的因素,本文重点研究了复合乳化剂的配比,丙烯酰胺反相微乳液体系的形成机理,并通过紫外分光光度计,旋转粘度计等对微乳液体系可能形成的微观结构和特性进行了分析探讨。其后,采用氧化还原引发剂体系进行了微乳液聚合,并对聚丙烯酰胺的物理性能,化学结构,相对分子质量等进行了测定和表征。     

丙烯酰胺反相微乳液的制备与表征

用复合乳化剂(Span 80/OP-10)制备了稳定的丙烯酰胺(AM)反相微乳液,研究了温度、复合乳化剂的配比及浓度对单体增溶量的影响,并通过紫外分光光度计、乌氏黏度计等对微乳液体系的微观结构和特征进行了分析和表征.     

Triton X-100反相微乳液体系制备纳米粒子的研究进展

介绍了Triton X-100反相微乳液体系的形成机理、特性和制备纳米粒子的原理,总结了采用Triton X-100体系制备纳米粒子的影响因素。综述了近年来国内外用该微乳液系统制备纳米粒子的新进展,提出了该体系制备纳米颗粒存在的问题。     

反相微乳液聚合制备聚丙烯酰胺

选用ＳＰＡＮ８０－ＯＰ１０复合乳化剂，煤油为油相，进行了丙烯酰胺的反相微乳液聚合研究，制得了水溶解速度显著加快的聚丙烯酰胺，并对构成稳定微乳液的乳化剂ＨＬＢ值进行了研究。     

反相微乳液法制备纳米颗粒研究进展

综述了反相微乳液的形成机理、配制方法和目前利用反相微乳液技术制备纳米颗粒方面的研究进展，并对微乳液的配制及制备过程中影响纳米颗粒的主要因素进行了具体的讨论，还对微乳液技术的发展前景作了具体的讨论和分析。     

反相微乳液法制备纳米TiO2

以CTAB/正丁醇/正庚烷/NH.3H2O和CTAB/正丁醇/正庚烷/TiCl4反相双微乳液方式制备纳米TiO2,且采用SEM和FI-IR等分析手段对纳米TiO2的粒径、物相等方面进行分析。结果表明,在CTAB6.83g,正丁醇8.54mL,正庚烷30mL,2.4mo.lL-1的NH.3H2O6mL,0.6mo.lL-1的TiCl43mL的条件下,可以制备纳米TiO2。     

丙烯酰胺-丙烯酸钠反相微乳液聚合的研究

采用煤油做连续相,以MOA-3和OP-10为复合乳化剂,过硫酸钾-亚硫酸氢钠为氧化还原引发剂引发体系,进行丙烯酰胺(AM)和丙烯酸钠(SA)的反相微乳液共聚合反应,在单体浓度为55%～65%,引发剂浓度在0.1‰～0.4‰,乳化剂的浓度在20%～35%,聚合温度在30°C的条件下,在低转化率情况下得到了共聚合反应动力学方程近似为:RP∝[M]2.41[I]0.23[E]0.87;并考察了温度对聚合速率的影响,计算得到反应活化能为35.69kJ/mol。     

A retrospective look at developments in size exclusion chromatography from the early Hamielec research era to the present day

At the start of Archie Hamielec's research career, size exclusion chromatography (SEC) (including gel permeation chromatography [GPC]) was in its infancy as an analytical and preparative laboratory technique in polymer science and engineering. As described below, Archie Hamielec saw its potential early in his academic career and was among the group of pioneers who took it from a developing technique to what it is now. His group's work was instrumental in improving the understanding of the mechanism of separation in SEC and setting up best procedures for sample handling. In addition, much work was done to assess detectors to improve data collection and to obtain consistent/reliable measurements. Importantly, he established it as a key method for obtaining molecular size information to support research in polymer reaction engineering. Nowadays we take it for granted that we can use SEC to obtain molecular weight data rapidly and reliably with user-friendly computer-aided analyses. This ease of routine practicality stems from the base that the early researchers built. Although now it is a well-developed (almost ‘black box’) method there are still areas of novel interest into analysis of complex polymer samples. This has led to modern developments forging ahead in expanding the applicability of SEC as an analytical technique with the exploitation of multi-detector systems and novel detectors.     

Surfactant‐free nanoparticles of poly(DL‐lactide‐co‐glycolide) prepared with poly(L‐lactide)/ poly(ethylene glycol)

Surfactant‐free nanoparticles of poly(DL ‐lactide‐co‐glycolide) (PLGA) nanoparticles were prepared with or without poly(L ‐lactide)‐poly(ethylene oxide) (LE) diblock copolymer (abbreviated as PLGA/LE and PLGA nanoparticles) by dialysis method. LE diblock copolymer was used to make PLGA nanoparticles to alternate conventional surfactant. The size of PLGA and PLGA/LE nanoparticles was 295.3 ± 171.3 and 307.6 ± 27.2 nm, respectively, suggesting LE diblock copolymer might be coated onto the surface of nanoparticles. Observation of scanning electron microscope (SEM) showed that PLGA/LE nanoparticles have spherical shapes ranging ～ 200–500 nm. In ¹H‐NMR study, characteristic peaks of the methyl protons of PLGA disappeared in D₂O, whereas characteristic peaks of the methyl proton of both PEG and PLGA were shown in both CDCl₃ and D₂O, indicating that LE diblock copolymer coated on the surface of the PLGA nanoparticles. The higher the initial content of drug, the higher the drug contents and the lower the loading efficiency. PLGA/LE nanoparticles at higher drug contents resulted in slower adriamycin·HCl (ADR) release rate than that of lower drug contents. Also, slower release rate of ADR was achieved by entrapped into the PLGA/LE nanoparticles, whereas LE polymeric micelles showed rapid ADR release. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1116–1123, 2003     

Influence of temperature and penetration depth on photopolymerization of n‐butyl acrylate using a narrow channel reactor

The influence of temperature and reactor size on photopolymerization kinetics of n‐butyl acrylate (n‐BA) using narrow channel reactors has been investigated. Experimental results have shown that increase in temperature and decrease in size of the reactor increases the monomer conversion. The effect of temperature was studied by immersing the reactor in a water bath maintained at different temperatures. A narrow channel glass reactor, 900 mm long, with diameters 1.5 mm, 1.0 mm, and 0.5 mm respectively were used to study the effect of light penetration depth on the rate of polymerization and molecular weights of the polymer produced. The degree of branching in the polymer produced was also estimated and compared with published data. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Reaction of living polyTHF with amines: 4. Primary amines

Cationic living polyTHF reacts with primary amine rapidly under ambient conditions. When the amine is in excess the main product is a polymer possessing a terminal secondary amine ligand, and near quantitative conversion is achieved at ten fold excess. The proportion of mono- and disubstituted polymer formed at a given reagent ratio is insensitive to the nature of the amine. Surprisingly, therefore, it is found that the form of the un-neutralized amine product is dependent on the primary amine used, that from aniline exists as the free secondary amine whilst those from cyclohexylamine and n-butylamine exist as the acid salt. A hypothesis is put forward to explain these observations.     

Novel materials based on silicone–acrylate copolymer networks

This article presents a broad class of materials made by copolymerization of a family of telechelic free radically polymerizable siloxanes with various acrylate monomers that polymerize to form high T_g polymers. Films with properties ranging from strong elastomers to plastics have been obtained by UV‐initiated bulk copolymerization of functional siloxanes dissolved in acrylate monomers (in the presence of a photoinitiator). The molecular weight of the functional siloxanes, the nature of functional endgroups, the choice of (meth)acrylate comonomer, and the siloxane/acrylate ratio all have a rather dramatic effect on the morphology, and thus, on the properties of the copolymeric networks. Physical properties of the materials, such as optical appearance and mechanical and transport properties are correlated with the unique morphologies observed by TEM studies. Unusual properties such as reversible whitening of some of the materials and low Poisson ratios have been attributed to the microcavitation observed when high T_g acrylate domains interfere with the network deformation. Networks composed of high T_g acrylates (major fraction) coreacted with elastomeric siloxanes can provide heat‐shrinkable materials when they are elongated at temperatures higher than the T_g of the corresponding polyacrylates and quenched. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 159–180, 2001     

凝胶渗透色谱联用技术测定树脂分子质量

介绍了当前凝胶渗透色谱法测定树脂分子质量及其分布的情况,并将凝胶色谱柱与不同的检测器相连,如与黏度计、静态光散射、质谱技术、核磁共振等联用的方法,并且比较了它们用于测定树脂分子质量时各自的特点。     

好氧、厌氧/好氧交替和厌氧条件对碱减量废水处理效果研究

以聚酯纤维碱减量废水为研究对象,利用活性污泥法对比在好氧、厌氧/好氧交替和厌氧条件下对碱减量废水的处理效果.结果 表明,好氧条件下碱减量废水降解效果最佳,运行72 h时COD和UV254的去除率分别为97％和99％;厌氧/好氧交替条件次之,COD和UV254的去除率分别为80％和81％,厌氧条件下废水降解效率最低,CO...     

A study on polyurethane/acrylate crosslinked gel polymer electrolytes

2,4‐Toluene diisocyanate, poly(propylene glycol), poly(ethylene glycol) (PEG) and 2‐hydroxyethyl methacrylate were used to synthesize PEG–UA (urethane acrylate) monomer. The crosslinked polymer and gel polymer electrolytes were prepared in dioxane by free radical polymerization. The swelling behaviour, thermal degradation properties, morphology and ionic conductivity of the gel polymer electrolytes were investigated. With decrease in the proportion of dioxane used, the synthesized polymer's network density increased, its affinity with a solution of 1 M LiClO₄ in propylene carbonate (PC) decreased, and more microgel which diffused in the network. At the same time, the conductivity increased and reached 4 × 10^?4 S cm^?1 at 25 °C. Copyright © 2003 Society of Chemical Industry     

Effect of vinylidene chloride content on film-formation property of vinylidene chloride-methyl acrylate copolymer latex

Minimum film-formation temperature (MFFT) of vinylidene chloride (VDC)-methyl acrylate (MA) copolymer latexes prepared by batch emulsion polymerization with various compositions from 20 to 97 wt % of VDC were measured. For latexes with VDC content below 90 wt %, MFFT was similar to polymer T_g. As VDC content increased beyond 90 wt %, the MFFT curve plotted against VDC content rose sharply, in contrast with the T_g curve that descended smoothly. Measurements of infrared absorption of latexes in the dispersed state, and X-ray diffraction and infrared absorption of lyophilized polymers were conducted on 40 : 60, 80 : 20, and 95 : 5 VDC-MA specimens. These observations indicated that only 95 : 5 VDC-MA specimens were highly crystalline. It was therefore believed that film-formation property of latex with high VDC content was significantly affected by polymer crystallinity of particles in the dispersed state. Morphology and oxygen gas transmission rate of heat-treated and non-heat-treated coatings of 95 : 5 VDC-MA latex were investigated. Heat treatment of coatings beyond the temperature at which crystalline polymer began to melt induced effective particle coalescence, resulting in reduced oxygen gas transmission rate. This supported our belief that film-formation property of VDC-MA latex with high VDC content was significantly affected by polymer crystallinity. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 565–572, 1998