Stability and demulsification of emulsions stabilized by asphaltenes or resins

Experimental data are presented to show the influence of asphaltenes and resins on the stability and demulsification of emulsions. It was found that emulsion stability was related to the concentrations of the asphaltene and resin in the crude oil, and the state of dispersion of the asphaltenes and resins (molecular vs colloidal) was critical to the strength or rigidity of interfacial films and hence to the stability of the emulsions. Based on this research, a possible emulsion minimization approach in refineries, which can be implemented utilizing microwave radiation, is also suggested. Comparing with conventional heating, microwave radiation can enhance the demulsification rate by an order of magnitude. The demulsification efficiency reaches 100% in a very short time under microwave radiation. (C) 2003 Elsevier Inc. All rights reserved.

Synthesis of N-Methylimidazolium Functionalized Strongly Basic Anion Exchange Resins for Adsorption of Cr(VI)

N-Methylimidazolium functionalized strongly basic anion exchange resins in the Cl- form (RCI) and SO46- form (R2SO4) were synthesized and employed for adsorption of Cr(VI) from aqueous solution. FT-IR and elementary analysis proved the structures of anion exchange resins and the content of functional groups. The gel-type strongly basic anion exchange resins had high thermal stability according to TGA and good chemical stability under the experimental conditions. The adsorption behaviors of Cr(VI) on RCI and R2SO4 were studied using the batch technique. It was shown that adsorption equilibrium was reached rapidly within 60 min. The adsorption data for RCI and R2SO4 were consistent with the Langmuir isotherm equation.

Study of PVT behavior of biaxially oriented polypropylene resins in the melting state

The PVT data of five kinds of biaxially oriented polypropylene (BOPP) Resins was measured by the PVT-100 apparatus. Thermal expansion coefficients (alpha) and isothermal compressibility (beta) were evaluated from Tait equation in the melting state and then compared with those fitted with the value of experiment. The results showed that it was reasonable to calculate alpha and beta with Tait equation in the melting state. At the same time, it was found that thermal expansion coefficients, isothermal compressibility and the melting temperature (T-m) of one of BOPP melts (S28C) were lower than those of the others in the same test conditions, indicating that the volume deformation of S28C resin is' less so that it could be realized to avoid arising surface defects of the film (biaxially oriented polypropylene film) due to. contracting, thereby decrease damage to the film in the subsequence process. Accordingly superior processing properties of S28C resin are confirmed from PVT. speciality.

Covalently attached multilayer assemblies containing photoreactive diazo-resins and conducting polyaniline

We reported on the multilayer architecture containing diazo-resins (DAR) as polycations and polyaniline poly(aniline-co-N-propanesulfonic acid aniline) (PAPSAH) as polyanions held together by electrostatic interaction. Upon UV irradiation, the adjacent interfaces of the multilayer reacted to form a covalently crosslinking structure which greatly improved the stability of the films as confirmed by solvent etching experiments. These changes were confirmed by UV-Vis and FTIR spectroscopy. The thickness of the covalently attached films were characterized with small angle X-ray diffraction (SAXD) and a value of 30.0 Angstrom per bilayer was obtained. This type of film was further characterized by cyclic voltammetry which showed that the electroactive property of PAPSAH was still kept in the films after photoreaction. (C) 2000 Elsevier Science B.V. All rights reserved.

The preparation and property studies of transparent resins containing rare earth terbium(III) complex

The binary and ternary rare-earth terbium(m) complexes were introduced into the styrene/alpha -methylacrylic acid copolymerization system, and some optical resins that possess a high transparency in visible light region were obtained. The study of the optical property showed that they have good luminescent properties such as a high luminous intensity and a long luminous lifetime, In addition, we investigated the relationship among the transparency, the luminescent property of the copolymer, and the content of the components in the polymeric system. The results indicated that the optical resins can provide a relatively stable environment for composite rare earth complexes, which is good to exhibit the luminescent properties of rare earth complexes. At the same time, the rare earth complexes can offer the transparent resin a novel function.

Morphologies and mechanical properties of epoxy resins toughened by hydroxyl-terminated butadiene-acrylonitrile copolymer

The morphologies and mechanical properties of epoxy resins toughened by hydroxyl-terminated butadiene-acrylonitrile copolymer (HTBN) and cured with hexahydrophthalic anhydride were studied, The results show that the level of HTBN in epoxy resin, content of acrylonitrile in HTBN and curing temperature influence the morphology and then influence the mechanical properties of cured epoxy resin.

耐热树脂的增强与增韧研究

耐热树脂或称特种工程塑料主要包括聚芳飒类、聚醚酮类、聚芳酷、液晶类、聚酞亚胺和聚苯硫醚等。长春应化所已获得有关聚芳醚酮（PEK-C），聚芳醚砜（PES-C）和聚酞亚胺（PEI）等特种工程塑料的专利12项。在特种工程塑料中，PEK-C，PES-C和PEI有着最高的机械强度（室温下的拉伸强度在100MPa以上）。PES-C和PEI的耐热等级最高（热变形温度分别为225℃和220-260℃）。PE工有极好的阻燃性（氧指数为47）和耐磨性。而PEK-C的加工性好、韧性高、耐磨损和抗电击穿等性质突出，其综合物性与英国ICI公司的聚醚醚酮（PEEK）相近，是良好的高性能复合材料基体树脂。具有优异综合物性的PEK-C、PES-C、PEI及其改性系列材料在机械、电子电气、军工、医疗及食品等许多领域有着广泛的应用前景。近年来，长春应化所在酞侧基聚芳醚酮和聚芳醚矾的结构一加工一物性关系及开发应用等方面作了大量的研究工作，主要涉及此两种聚合物的粘弹性、屈服行为、断裂行为、转变与松弛以及复合与共混等方面内容。这些研究工作表明，酞侧基聚芳醚酮和聚芳醚矾经过共混和复合改性能够具有更优异的使用性能，而且这些研究中的一些方法同样可以应用于其它耐热树脂的改性。高分子材料科学的发展趋势就是在更深层次上把握材料的结构特点及其与宏观物性间的相互关耽达到高分子分子设计和材料设计的目标，实现高性能化和高功能化使现有的高分子材料找到更广泛而合理的应用。工程塑料的高性能化是高分子材料科学近年来发展的一个主要方向。为满足航天航空、电子信息、汽车工业家用电器以及机械等多方面技术领域的需要，要求材料的机械性能、耐热性、耐腐蚀性和长期使用性等性能进一步提高。在现有工程塑料品种的基础上通过共混增韧、复合增强等改性方法使其成为高性能的结构材料，是高分子材料私｝学的前沿课题及重要任务。本文采用熔融加工的方法制备了PEK-C和PES-C耐热树脂的共混与复合材料，利用热分析、力学性能检测、微观形貌观察、加工性能检测等手段研究了共混物及复合材料的结构与性能。通过对PEK-C和PES-C的冲击断裂过程的研究，我们发现，两种材料在裂纹起始扩展时所能承受的最大应力值相同，但PES-C的裂纹引发（ti）和扩展（tp）所需时间仅是PEK-C的一半，此即PES-C的冲击强度（I）和断裂韧性（KIC）较低的原因。因此，如能延长裂纹引发和扩展的时间，也就是说如能扩大断裂过程区，抑制裂纹的早期形成就能达到增韧的目的。在PES-C的增韧研究方面，我们可以借鉴通用塑料的增韧方法，即在高聚物基体中，以适当的手段掺加第二相粒子，通过粒子的变形和引发基体在粒子周围产生剪切屈服或银纹化等作用机理，实现增韧目的。所不同的是，对PES-C类耐热树脂来说，实现增韧的同时应保持材料原有的高强度和高耐热性等优良险质。另一方面，由于耐热树脂的加工温度极高，适合于通用塑料的偶联剂等界面改性技术已不再适用于特种工程塑料。针对PES-C的增韧方法和机理的研究工作可归纳为以下三个方面：①刚性有机粒子（PPS，LCP等）增韧；②柔性有机粒子（UHMWPE）增韧；③刚性无机粒子（硅灰石）增韧。物理老化或结构松弛效应使得高聚物材料的结构和宏观物性随时间而发生变化。随时间的增长，PES-C和PES-C／PPS共混物的拉伸强度增加、冲击韧性减小，而且这种变化趋势表现出物理老化过程的自衰减特性。研究结果表明，PES-C／pps共棍物的结构松弛速率比PES-C慢。具有良好界面相互作用的PES一C／PPS共混物材料的强度和韧性始终高于PES-C纯组份聚合物。因此说，pES-C／PPS共混物不仅具有良好的短期性能，而且在高温下长期使用过程中，其力学性能将始终优于纯组份聚合物。我们研究了热固性聚酞亚胺预聚物（P01）增容聚芳醚酮／聚苯硫醚共混物的热学性能、力学性能、形态结构及加工性，对POI在聚芳醚酮／聚苯硫醚共混物中所起的增容作用机理进行了初步探讨。实验发现，PEK-C／PPS共混物在保持PEK一C原有的高强度和高模量的同时，加工流动性和韧性得到一定程度的改善。PEK-C／ppS／Pm三元共混物中，少量的POI能够控制PPS分散相的相区尺寸，防止分散相粒子的自凝聚，起到了增容剂的作用。热固性高聚物预聚体可用于增容热塑性高聚物共混体系，这种增容方法有其特殊性和新颖性，增容后的聚芳醚酮／聚苯硫醚共棍物的力学性能得以改善。利用纤维可以作为结晶性高聚物的异相成核剂的特性，将合适的结晶性高聚物与非晶高聚物共混，可以在在一定程度上改善非晶高聚物与纤维间的界面粘结，提高纤维增强效率。这种方法对PEK-C类耐热树脂尤为重要。通过与即S共混，玻纤增强PEK-C复合材料中纤维与基体间的界面粘结以及纤维的长径比明显增加，因而复合材料的强度和模量显著提高，而且加工流动性也得到一定程度的改善。从考虑综合物性的角度出发，利用结晶性高聚物改善纤维与非晶树脂基体间的界面粘结时，结晶性高聚物的用量存在一个最佳值。与PEEK／GF复合材料相比，PEK-C／PPS／GF复合材料在加工能耗、价格等方面存在很大优势，可以预期这一高性能复合材料可应用于制造高强度、高耐热、耐腐蚀、耐磨损、耐疲劳的往复运动部件、振动或转动等机械零部件。

ABS树脂形态结构及力学性能的研究

ABS树脂具有优良的抗冲击性、耐热性和耐化学药品性，还具有易加工性、制品尺寸稳定性等特点，广泛应用于工业领域。ABS树脂的制备方法有许多种，目前应用最为广泛的是乳液接枝ABS共聚物一本体SAN掺混法。首先采用乳液聚合方法合成聚丁二烯胶乳，然后将其作为种子进行苯乙烯和丙烯睛的接枝共聚反应生成ABS接枝共聚物；采用本体法制备SAN树脂；最后将ABS接枝共聚物（冲击改性剂）和SAN树脂共混制得ABS树脂。由此看来，ABS接枝共聚物的合成是控制ABS树脂性能的关键。目前国产ABS树脂普遍存在的问题是ABS接枝共聚物的增韧效率低。影响其增韧效率的因素包括共聚单体的组成、橡胶相的组成及结构、橡胶与树脂之间的界面结合力等。因此为提高ABS冲击改性剂的增韧效率，拓宽ABS树脂的应用领域，应合理地控制ABS冲击改性剂的合成参数。本论文采用种子乳液聚合方法在PB（聚丁二烯）橡胶粒子上接枝共聚苯乙烯和丙烯睛合成ABS接枝共聚物，将其作为冲击改性剂与SAN树脂共混制备ABS树脂，对ABS树脂形态结构及力学性能进行了研究。主要研究内容和结论如下：1、研究ABS接枝共聚物中PB／SAN组成、TDDM（叔十二碳硫醇）链转移剂和CHP（过氧化氢异丙苯）用量、单体加料方式及引发剂类型对SAN在PB橡胶粒子上接枝度的影响。sAN在PB橡胶粒子上的接枝度随PB和TDDM含量的增加而降低；随CHP用量的增加先增加后降低；随单体滴加时间的延长而增加，但过分延长时间则对接枝度影响很小；与AIBN（偶氮二异丁睛）和K25208（过硫酸钾）相比，采用氧化一还原引发体系得到的接枝度较高。2、研究ABS接枝共聚物的力学性能。DMA结果表明，随着PB含量的增加，ABS接枝共聚物的储能模量降低，橡胶相的玻璃化转变温度向低温移动，内耗峰值增加。拉伸试验结果表明，当体系中没有TDDM时，不同橡胶含量的ABS接枝共聚物均没有发生明显的应变软化；当加入适量的TDDM后，材料发生应变软化，且随着TDDM用量的增加，材料的屈服应力提高。3、研究ABS接枝共聚物对ABS树脂形态结构及力学性能的影响。ABS接枝共聚物中PB／SAN组成及TDDM链转移剂用量影响ABs树脂中橡胶粒子的内部形态及橡胶粒子在基体中的分散。在合成ABS接枝共聚物的过程中，应合理地调节PB／SAN组成及TDDM的用量以使ABS接枝共聚物达到最大的增韧效率。4、研究ABS树脂在不同应变速率下的断裂行为及形变机理。结果表明，橡胶含量及应变速率影响ABS树脂的力学性能，但没有改变ABS树脂的形变机理。ABS树脂的形变机理包括银纹、橡胶粒子的空洞化及基体的剪切屈服，其中占主导地位的是橡胶粒子的空洞化及基体的剪切屈服。

The solid-liquid extraction of yttrium from rare earths by solvent (ionic liquid) impreganated resin coupled with complexing method

A kind of solvent (ionic liquid) impreganated resin (IL-SIR) was developed herein for ameliorating imidazolium-type IL-based liquid-liquid extraction of metal ions. In this study, [C(8)mim][PF6] containing Cyanex923 was immobilized on XAD-7 resin for solid-liquid extraction of rare earth (RE). The solid-liquid extraction contributed to ameliorating mass transfer efficiency, i.e. shortening equilibrium time from 40 min to 20 min, increasing extraction efficiency from 29% to 80%. In additional, the novel IL-SIR could separate Y(III) from Sc(III), Ho(III), Er(III), Yb(III) effectively by adding water-soluble complexing agent.

Characterization of the Microstructure of Bimodal HDPE Resin

In this work, two industrial bimodal high density polyethylene resins, resin A and resin B having similar molecular weight (M-w), molecular weight distribution (M-wD), and short-chain branching (SCB) content but different mechanical properties, were fractionated through cross-fractionation. The fractions were further, characterized by GPC, C-13 NMR, DSC AND FT IR techniques. These two resins were firstly fractionated into two franctions, i.e. high-temperature and low temperature fractions, via preparative solution crystallization fractionation. Resin A with much better mechanical properties contains more high-temperature fractions with longer crystalizable sequences. The SCB content in the low temperature fraction of resin A is lower than the of resin B. Both low-temperature fractions were then further fractionated using solvent gradient fractionation (SGF). The characterization of SGF fraction indicates that most of the branches fall into the high molecular weight chain in both low-temperature fractions.

Preliminary study on melt-spinning, adhesion and adsorption properties of poly(lactic acid)

For the purpose of manufacturing cigarette filter tows and filter rods, the melt-spinning, adhesion and adsorption properties of poly(lactic acid) were studied. The rheological measurements were performed to examine the effects of various processing conditions on the melt flowability and spinnability, including those of residual moisture. The melt spinning and post-processings were followed by determining the molecular weight, thermal and mechanical properties of the fibers. The results obtained were useful to establishing the specification of the PLA resins for filter tows and filter rods manufacturing and to choosing proper melt-spinning and post-processing technologies.