Effect of comb-type copolymer on crystallization of paraffin from waxy oils and methyl ethyl ketone (MEK) -toluene dewaxing

In this research, maleic anhydride-α-octadecene copolymer and its derivative with phenylethylamine was synthesized and its effect on the crystallization of paraffins was investigated. This derivative, when added into second cut of vacuum gas oil and forth cut of vacuum gas oil, increases the size and improves aggregation of paraffin crystals observed by polarizing light microscopy, increases onset temperature and enthalpy of paraffin crystallization determined by differential scanning calorimetry, improves the dewaxing efficiency with dosage of 100?ppm explored by MEK-toluene dewaxing.     

合成丁苯嵌段共聚物的影响因素

采用负离子溶液聚合方法制备了丁苯嵌段共聚物，研究了引发剂、活化剂、偶合剂、终止剂对聚合产物性能的影响。     

聚乙烯辐照接枝体系中添加金属盐对接技率的影响

采用辐照接枝的方法，在高密度聚乙烯(HDPE)上接枝丙烯酸(AA)和对苯乙烯磺酸钠(SSS)，从而削备出了一种含羧酸基团和磺酸基团的阳离子交换膜。详细研究了接枝体系中引入添加剂醋酸钠或氯化钠对接枝率的变化规律．实验表明，在预辐照接枝和共辐照接枝中，当AA接技PE或AA与SSS共同接枝PE时，强碱弱酸盐醋酸钠通过pH效应同离子效应对接枝率呈现复杂的影响，而中性盐氯化钠经离子对效应显著提高接枝率。     

乙烯基硅氧烷改性苯丙乳液的研究

在苯乙烯 -丙烯酸酯乳液共聚反应后期 ,加入少量乙烯基硅氧烷 ,制得改性苯丙乳液 ,通过红外光谱初步确定了聚合物结构。研究了反应温度、反应时间、有机硅加入方式、乳化剂用量等因素对反应进程、乳液稳定性及涂膜性能的影响。     

HDPE／PS／HDPE－g－PS合金的相容性和力学性能研究

用自制接枝共聚物ＧＲ－Ⅰ、ＧＲ－Ⅱ相容剂研究其对ＨＤＰＥ／ＰＳ共混物相容性和力学性能的影响。通过ＳＥＭ、ＤＭＡ、ＤＳＣ和力学性能测试表征，表明在ＨＤＰＥ／ＰＳ共混中加入这些相容剂其相容性和力学性能有一定提高     

PP－g－AA的制备和表征

用熔融接枝方法制备了聚丙烯－ｇ－丙烯酸（ＰＰ－ｇ－ＡＡ）。用光电子能谱，广角Ｘ射线衍射，红外光谱和化学滴定方法对接枝物进行了定性和定量表征。讨论了单体和引发剂浓度对接枝率的影响，确定了用红外光谱法测定接枝物含量的经验公式     

A facile and efficient method for preparation of chiral supported poly(styrene–divinylbenzene) copolymers

A new and efficient method for preparation of optically active poly(styrene–divinylbenzene) copolymers (PS-DVB) is presented here. This is carried out by Friedel–Crafts acylation reaction of chiral N-phthaloyl -leucine acid chloride with PS-DVB beads in the presence of aluminum chloride as Lewis acid catalyst and 1,2-dichloroethane as the solvent at ambient temperature. Reagents’ amounts and reaction conditions are mentioned and four samples with different amounts of functionality have been prepared. Final products were characterized by FT-IR and elemental analysis. The results obtained confirm that the above modification in preparation of chiral supported PS-DVB has been achieved well and in moderate yield.     

Single‐Source Precursors For Synthesizing Bifunctional Periodic Mesoporous Organosilicas

A new class of bifunctional periodic mesoporous organosilicas (PMOs) composed of organosilicate building blocks with two different silicon sites have been synthesized from the single‐source bifunctional organosilica precursors tris(triethoxysilylethyl)ethoxysilane and bis(triethoxysilylethyl)diethoxysilane, respectively denoted MT³‐PMO and DT²‐PMO. The synthesis of these PMOs is achieved by the co‐assembly of a triblock‐copolymer Pluronic P123 template with the bifunctional organosilica precursor under acid‐catalyzed and inorganic‐salt‐assisted conditions. After template removal through solvent extraction, the MT³‐PMO and DT²‐PMO so obtained show well‐ordered mesopores and display large pore diameters (6–7 nm) and pore volumes (0.6–0.8 cm³ g^–1) with a narrow pore‐size distribution and high surface areas (700–800 m³ g^–1).     

Complex formation of montmorillonite clay with polymers. Part 2: The use of montmorillonite clay–vinyl monomer complex as a comonomer in the copolymerization reaction of styrene–acrylonitrile monomers

The bulk copolymerization of styrene–acrylonitrile monomers using styrene‐N⁺–montmorillonite complex as a comonomer in the polymerization was studied. The X‐ray diffraction (XRD) analysis showed that part of the styrene‐N⁺–montmorillonite complex remained non‐dispersed (immiscible) and the copolymer was excluded from the interlayer of the immiscible part of the clay. The successive chemical extraction process revealed that a reasonable amount of the styrene–acrylonitrile copolymer was directly attached to the styrene‐N⁺–montmorillonite complex and enveloped the clay. Highly exfoliated clay lamella and nanospheres (3–5 nm) were observed by transmission electron microscopy (TEM). The montmorillonite clay assume two different morphologies, immiscible and exfoliated, on the basis of the XRD and TEM data. A simple method of calculation of the ratio of the exfoliated/immiscible amounts of the clay indicated that the amount of the styrene‐N⁺–montmorillonite complex exfoliated into separate lamella was 40 % (w/w) of the amount of the clay samples containing 2 % of the (styrene‐N⁺–montmorillonite complex) clay. This amount of exfoliated clay decreases with the increase of the concentration of the clay. The presence of the styrene‐N⁺–montmorillonite clay in the copolymerization reaction had a minor effect on both the copolymer composition and the molecular weight. Modification of the clay with the derivatized styrene monomer can achieve a nanocomposite using a percentage no more than 4 % (w/w) of complex in the copolymer. Copyright © 2004 Society of Chemical Industry