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1.
To improve dispersion stability of water soluble phenol-fomaldehyde resin (PFR) in relatively low salinity water, the effect of hydrophobically associating polymer (HAP) on the dispersion property of PFR in NaCl solution was studied by the measurement of the size and zeta potential of PFR, HAP, and PFR/HAP molecule aggregates in NaCl solution, and the turbidity of PFR and PFR/HAP dispersions. The results show that due to the hydrophobically group on HAP molecule has similar structure as molecular structure of PFR and stronger hydrophobically association of HAP molecules in NaCl solution, HAP, and PFR molecules can form complex molecule aggregates together. The formation of the complex molecule aggregates enhanced the stability of PFR dispersion in NaCl solution.  相似文献   

2.
3.
聚合物分散剂对氟虫脲水悬浮剂分散稳定性的影响   总被引:4,自引:0,他引:4  
通过测定药物颗粒界面Zeta电位和平均粒径, 研究了聚合物分散剂苯乙烯磺酸聚合物钠盐(GY-D08)用量、pH和盐离子对氟虫脲水悬浮剂分散稳定性的影响, 研究结果表明, 分散剂GY-D08的加入量与水悬浮剂分散效果密切相关, 制备质量分数为5%氟虫脲水悬浮剂的GY-D08最佳用量为2%, GY-D08用量过多或过少都会使分散效果下降; pH影响分散剂GY-D08在水中的电离能力, 当pH=9时, GY-D08分子完全电离, 能为颗粒提供较大的静电位阻, 水悬浮剂分散稳定性最好; Mg2+或Ca2+压缩颗粒界面的双电层, 降低Zeta电位, 使颗粒因带电量减少而聚结, 导致水悬浮剂分散稳定性变差, 且Mg2+或Ca2+浓度愈大, 其分散稳定性愈差; 当离子浓度相同时, Ca2+压缩双电层的能力比Mg2+强, 添加Ca2+后的水悬浮剂的分散稳定性更差.  相似文献   

4.
多孔酚醛树脂热解碳材料的制备与结构   总被引:2,自引:0,他引:2  
王存国  林琳  路乃群  赵强  孙琳  赵树高  王荣顺 《化学学报》2008,66(16):1909-1914
用苯酚和甲醛在氨水催化下合成了可溶性酚醛树脂, 经掺杂不同质量比发泡剂(氯化锌)后在惰性气氛下进行热裂解(500~900 ℃), 制备了多孔热解碳导电材料(PPAS); 用FTIR, XRD, TG, SEM, BET等方法对所制备材料进行了结构表征, 详细讨论了发泡剂的加入对热解碳导电材料结构和性能的影响. 研究发现: 酚醛树脂经掺杂一定量发泡剂后再进行热裂解, 一方面加快了酚醛树脂分子间的脱水速度, 降低了热裂解温度范围; 另一方面, 裂解产物内部结构的微晶尺寸和层间距发生了明显变化, 未掺杂发泡剂的裂解产物呈现尖锐棱角的无定形结构, 而掺杂发泡剂的裂解产物则为多孔的球形和椭球形结构; 表面吸附实验测试结果表明, 当酚醛树脂与发泡剂的质量比为1∶3, 升温速率为30 ℃/h, 热裂解温度为600 ℃时, 热裂解产物的比表面积可达2150 m2•g-1, 平均孔径在11 Å左右.  相似文献   

5.
采用量子化学MNDO和CNDO/2-CO计算方法,对聚偶氮乙烯(C2H2N2)23种异构体的稳定性进行了比较,指出聚偶氮乙烯和聚异亚甲基亚胺分子的稳定性比聚亚甲基亚胺高,分析了造成稳定性差异的原因。能带结构计算表明:三者中聚异亚甲基亚胺的导电性能最好,可望具有较高的本征和掺杂电导率。  相似文献   

6.
Soluble phenol formaldehyde resin containing hydroxymethyl groups has been used to modify sulfonated poly(ether ether ketone) (SPEEK). Modification has been carried out with films containing both the polymers and using dimethyl formamide (DMF) as casting solvent at various temperatures under reduced pressure. Associated solvent and the hydrogen‐bonded by‐product dimethyl amine (DMA) were removed through mild alkali–acid–water treatment. Cured and treated films show good and consistent mechanical properties, water uptake (22–25%), ion‐exchange capacity (1.1–1.5 meq/g) and proton conductivity (125–150 mS/cm) at 30°C and hold promise for application in fuel cells, as indicated by a polarization study in a fuel cell test station. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

7.
聚丙烯酸盐增稠剂;;耐电解质性能;长链疏水缔合单体;溶液聚合;反相乳液聚合;聚合工艺对聚丙烯酸盐增稠性能的影响  相似文献   

8.
高分子吸附;等离子体改性对酞菁铜在水中分散稳定性的影响  相似文献   

9.
A series of ferroelectric poly(vinylidene fluoride-trifluoroethylene- chlorotrifluoroethylene), P(VDF-TrFE-CTFE), have been synthesized by a two-step approach. The first step is copolymerization of VDF and CTFE via solution or suspension methods to produce P(VDF-CTFE) copolymers with different molecular weights. The second step is partial de-chlorination to convert copolymers into P(VDF-TrFE-CTFE) terpolymers with precisely controlled compositions. The effect of molecular weight, molecular weight distribution and uniaxially stretching on the dielectric properties has been investigated over a broad range of temperature and frequency. The X-ray diffraction patterns and DSC curves demonstrate the coexistence of the multiple phases in the terpolymers. The dielectric spectra depict the local relaxation processes and relaxor ferroelectric behavior on the basis of the dielectric loss tangent as a function of temperature.  相似文献   

10.
镍盐和氧化镍在NaY沸石中存在状态研究   总被引:1,自引:0,他引:1  
高滋  崔峻 《物理化学学报》1994,10(11):992-997
用XRD、EXAFS和TPR方法研究了Ni(NO3)2/NaY和NiO/NaY分散体系。在沸石上,Ni(NO3)2的分散比NiO容易得多。XRD相定量方法测定的NiO在NaY沸石上的分散阈值很低,仅为密置单层容量的2%左右。在分散阈值关NiO在沸石上处于分散相和笼外小晶粒两种状态。分散相NiO比笼外NiO小晶粒难还原。样品中NiO含量超过阈值时,笼外小晶粒长大成XRD可检测的较大晶粒。  相似文献   

11.
邻甲酚醛环氧树脂/聚氨酯互穿聚合物网络的形态与性能   总被引:1,自引:0,他引:1  
邻甲酚醛环氧树脂/聚氨酯互穿聚合物网络的形态与性能;互穿聚合物网络; 邻甲酚醛环氧树脂; 聚氨酯; 力学性能; 玻璃化转变温度  相似文献   

12.
Abstract

Semi‐ and full‐interpenetrating polymer networks (IPNs) of uralkyd (UA) resin based on hydrogenated castor oil and poly(butyl acrylate) (PBA) were prepared by the sequential mode of synthesis. These IPNs were characterized for their resistance to thermal behavior, swelling (%), and mechanical properties. The morphology of the IPNs was studied by scanning electron microscopy (SEM). The effect of the variations of the blend ratios on the above‐mentioned properties was examined. The mechanical properties significantly enhanced by increasing UA component in the blend. Full‐IPNs exhibited higher apparent densities, mechanical properties, and thermal stability than the corresponding semi‐IPNs.  相似文献   

13.
采用聚合和掺杂同时进行的反向胶束体系制备了粒径分散较小的聚3,4-乙烯二氧噻吩(PEDOT)纳米粒子, 利用紫外-可见光光谱(UV-Vis)、X射线衍射(XRD)和扫描电子显微镜(SEM)等分析方法对纳米粒子进行了表征. 实验结果发现, 氧化剂用量、超声处理、聚合温度及掺杂程度对PEDOT纳米粒子的形貌、电性能及热稳定性有不同程度的影响. 根据实验结果对反向胶束法制备PEDOT纳米粒子过程进行优化发现, 在PEDOT纳米粒子聚合过程中, 甲基苯磺酸有效掺杂浓度约为0.17 mol/L时, PEDOT链的取向最规则, 在6.7°, 12.7°, 25°出现衍射峰, 掺杂剂的有效掺杂使得纳米粒子中分子链的取向不同, 并可以获得较高的电导率(>100 S/cm)的PEDOT纳米粒子, 当粒子的尺寸小于20 nm后电导率降低; 热失重法(TG)分析结果表明, PEDOT纳米粒子的热稳定性比普通块材好, 掺杂剂浓度对纳米粒子的热稳定性有一定影响.  相似文献   

14.

The surface physicochemical properties of aminosulfonate formaldehyde condensates (ASP) and naphthalene sulfonate formaldehyde condensates (FDN) and the dispersion effect on cement paste were investigated. The results showed that these two superplastcizers could hardly reduce the surface tension of aqueous solution, and the surface activity and foam production was rather weak. The adsorption of ASP and FDN on the cement particles followed the Langmuir adsorption equation, characterized as monolayer adsorption. The maximum adsorptive amount of ASP on the cement particles was 3.83 mg/g at 20°C, and the adsorption rate constant was 1.00 s?1, which were less than those of FDN, respectively. The ζ potential of cement particles containing ASP was larger than that containing FDN, and the loss of ζ potential was much less. Study on the XPS spectrograms presented that, the thickness of adsorption layer of ASP on the cement particles was 7.26 nm, while that of FDN was 1.50 nm. It could be concluded that the electrostatic repulsion effect and steric repulsion effect of ASP were stronger than those of FDN, hence ASP had better dispersion effect and fluidity‐retaining ability on the cement paste. When the dosage of superplasticizer was 0.5 wt% of the cement, the fluidity of cement paste with adding ASP was 270 mm, while that with adding FDN was only 150 mm at a mass ratio of water to cement of 0.28. The residual fluidity of cement paste with adding ASP was 167 mm with 2.5 h elapsed at an initial fluidity of 200 mm, while that with adding FDN was only 101 mm.  相似文献   

15.
通过单体4-[(2,5-二溴苯)乙炔基]苯胺和1,4-二乙炔基-2,5-二戊氧基苯之间的Sonogashira偶合反应合成了带有p-氨基苯乙炔基共轭侧基的聚对苯撑乙炔((PAnPE)). 该共轭聚合物的THF溶液((2××10--5 mol•·L--1))在473和519 nm处呈现两个比较强的荧光发射峰. 通过调节在聚合物PAnPE-THF溶液中所加入三种沉淀剂((甲醇、乙酸、稀盐酸溶液))的体积比例, 来改变PAnPE分子链的聚集态结构, 进而研究对其发光性能的影响规律. 实验结果表明: 由于沉淀剂与聚合物PAnPE分子链之间相互作用能力与方式的不同, PAnPE两个荧光峰的发射强度因聚合物分子链聚集结构不同而呈现不同的变化规律, 这有助于实现在化学传感器中的应用.  相似文献   

16.
The miscibility and thermal properties of polyethylene oxide(PEO)/oligoester resin (OER) blends and PEO/crosslinked polyester (PER) blends were studied by differential scanning calorimetry (DSC). The effect of quenching process on the crystallization behavior of PEO for these two systems were investigated and discussed in details. It has been found that a single, composition dependent glass transition temperature (Tg) was observed for all the blends, indicating that the two systems are miscible in the amorphous state at overall compositions. From the melting point depression of PEO, the interaction parameter χ12 for PEO/OER blends and that for PEO/PER blends were found to be −1.29 and −2.01, respectively. The negative values of χ12 confirmed that both PEO/OER blends and PEO/PER blends are miscible in the molten state. Quenching process has a greater hindrance on the crystallization of PEO/OER blends than on that of PEO/PER blends. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3161–3168, 1997  相似文献   

17.
表面接枝分子印迹聚合物微球的合成及评价   总被引:5,自引:0,他引:5  
李保利  张敏  姜萍  董襄朝 《化学学报》2007,65(10):955-961
将聚苯乙烯-二乙烯苯微球表面功能基化, 引入引发转移终止剂(initiator-transfer-terminator agent, iniferter), 以活性自由基聚合方式研究了球形树脂表面合成印迹聚合物的方法. 在紫外光引发下, 以左旋麻黄碱为印迹分子, 甲基丙烯酸为功能单体, 在接枝Iniferter后的微球表面进行分子印迹聚合物接枝实验, 并使用不同的反应条件, 探讨了表面接枝印迹层微球制备条件对于识别能力的影响. 平衡吸附的结果表明, 表面接枝聚苯乙烯-二乙烯苯微球对于印迹分子具有亲和能力及选择性, 其识别能力来自于印迹得到的识别位点.  相似文献   

18.
IntroductionIt is well known that PVC is a kind of valuableplastic and used in many fields.But PVC isunstable against heat and light,and at the heat-molding step,the thermal decomposition of it maytake place.Finally,the decomposition will reducethe mechanical strength and lose otherproperties ofPVC.In order to overcome those disadvantages,athermal stabilizer is added in the PVC material toreduce the thermal decomposition,and organiccompounds of metals such as Sn,Pb,Ca,Ba,Znand Cd are u…  相似文献   

19.
詹梦雄  余荣清 《电化学》1995,1(3):362-365
C_(60)球烯是具有高度对称性的全碳原子簇,它既是电子受体,又是电子给体,表现出特有的光物理与光化学性能 ̄[1,2].近十多年来众多的研究者对具有电子给体和电子受体的共轭π电子体系化合物在光照下的行为进行了深入研究 ̄[3],认为用它作为有机光电子功能材料具有十分广阔的前景。随着人们对球烯研究的不断深入,尤其是宏观量球烯的合成与分离已日趋完善,以球烯为基础的有机光电材料必将越来越受到重视.金属酞青化合物由于拥有众多π电子的共轭体系,具有良好的光敏、半导体等性能,是较好的有机光电材料 ̄[4.5].但在可见光区,其光敏性仍不够强,本文以ZnPc掺杂C_(60)探索其光电性能,以期提高其光敏性.同类研究尚未见文献报道.  相似文献   

20.
Palygorskite was dispersed by various organic solvents and water, and the effects of solvent types on its microstructure, dispersion degree, and colloidal properties were investigated by infrared spectroscopy (IR), x-ray diffraction (XRD), and nitrogen adsorption-desorption isotherm (BET), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and rheological analyses. It was found that dimethyl sulfoxide and dimethyl formamide molecules may attach onto the surface of palygorskite and cause a complete disappearance of micropores. Solvent parameters govern the dispersion degree of palygorskite, and dimethyl sulfoxide and dimethyl formamide are good solvents to disperse palygorskite aggregates in contrast to ethanol and isopropanol. Colloidal stability and rheological tests suggested dimethyl sulfoxide-dispersed palygorskite can form more stable suspension with higher shear stress and modulus, but isopropanol-dispersed palygorskite may rapidly subside in suspension and show poor colloidal properties.  相似文献   

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