不同金属离子及胺中和的磺化丁基橡胶离聚体的性能

研究了不同金属离子及胺中和的磺化丁基橡胶离聚体的熔融流动性及力学性能。结果表明,随着硬脂酸锌加入量的增加,锂离聚体的熔融黏度降低,拉伸强度增大;随离聚体中磺酸基含量的增加,锂离聚体的熔融黏度和拉伸强度增大。对于一价金属离子中和的离聚体,其熔融黏度及拉伸强度随着离子电位的降低而减小;对于二价金属离子中和的离聚体,随着离子电位的下降及共价性的增加,熔融黏度下降而拉伸强度增大。用胺中和的离聚体,硬脂酸锌的影响较小,未加硬脂酸锌的离聚体具有较高的扯断伸长率及较低的永久变形,是良好的热塑性弹性体;随离聚体中磺酸基含量的增加,乙胺离聚体的拉伸强度增大。对于不同胺中和的离聚体,其拉伸强度按下列顺序依次降低：乙胺,三乙胺,二乙胺;乙胺,己胺,十二胺,十八胺。     

Melt flow and mechanical properties of sulfonated butyl rubber ionomers

Study of melt flow properties and mechanical properties of sulfonated butyl rubber ionomers showed that in the case of lithium ionomers addition of zinc stearate lowered obviously the melt viscosity, represented by torque value of a Brabender rheometer, and enhanced tensile strength of the ionomer up to 25% of zinc stearate, while in the case of ethylamine neutralized ionomer addition of zinc stearate lowered the melt viscosity not so obviously as in the case of lithium ionomer and slightly affected the tensile strength. Amine neutralized ionomers exhibited very low permanent sets, while the lithium ionomer showed much higher permanent set, which increased with sulfonate group and amount of zinc stearate added. Increase of neutralization degree below equivalent ratio of 1 significantly raised the melt viscosity and tensile strength. For monovalent cation ionomer, melt viscosity and tensile strength diminished with decreasing ionic potentials, but for divalent cation ionomers with increasing ionic potentials and with decreasing covalent character tensile strength decreased and melt viscosity increased. For different amine neutralized ionomers tensile strength decreased in the following orders: ethylamine > triethylamine > diethylamine; isopropylamine > ethylamine > tertiary butylamine > methylamine; ethylamine > hexylamine > dodecylamine > octadecylamine.     

Preparation of conductive polyaniline‐sulfonated EPDM ionomer composites from in situ emulsion polymerization and study of their properties

The composites of polyaniline (PAn) and zinc sulfonated ethylene–propylene–diene rubber (EPDM) ionomer were made by polymerization of aniline in the presence of the ionomer by using a direct, one‐step in situ emulsion polymerization technique. The ionomers were prepared by sulfonation of EPDM rubber with acetyl sulfate in petroleum ether, followed by neutralization with zinc acetate solution. The ionomers with sulfonate contents of 10, 24, and 42 mmol SO₃H/100 g were used for preparation of PAn/ionomer composites. The in situ polymerization of aniline was carried out in an emulsion comprising water and xylene containing the ionomer in the presence of dodecyl benzene sulfonic acid, acting as both a surfactant and a dopant for PAn. The composite was characterized by IR and WAXD. The composite obtained can be processed by melt method. The conductivity of the composite with lower sulfonate content was higher than that with higher sulfonate content. Conductivity of the composites exhibits a percolation threshold at about 13 wt % PAn. When the sulfonated content is 10 or 24 mmol SO₃H/100 g and PAn content is 4–10 wt %, the composites behave as a thermoplastic elastomers with high ultimate elongation and low permanent set. The conductivity of the composite after secondary doping with m‐cresol is higher than the composite before secondary doping by about one order. Addition of zinc stearate as an ionic plasticizer lowers both the conductivity and the mechanical strength of the composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2211–2217, 2004     

New polyisobutylene-based model elastomeric ionomers: RheoLogical behavior

The rheological behavior of sulfonated polyisobutylene based elastomeric ionomers has been studied. The effects of molecular architecture, type of cation, and addition of excess neutralization agent were investigated. The effect of temperature was studied to a limited extent. In a specific case, the influence of an ionic plasticizer, zinc stearate was also examined. It was found that in these telechelic ionomers where the ionic groups are located exclusively at the chain ends, significant Ionic interactions may persist even at 180°C. The zinc-neutralized ionomers had the lowest viscosity as compared to the corresponding potassium- or calcium-neutralized ionomers. The covalent character of zinc is believed responsible for this behavior. Other factors being constant, the triarm based ionomers are more viscous than the monofunctional ionomers. A mixture of monofunctional ionomers with the triarm, species is a model for dangling chain ends, and results in a slight lowering of the viscosity under the conditions studied. Zinc stearate acts as an ionic plasticizer. Upon the addition of 15 percent by weight of zinc-stearate to the ionomer, the low shear rate viscosity drops by several orders of magnitude and renders the ionomer thermally processable at moderate temperatures.     

Preparation,characterization, and some properties of ionomers from a sulfonated styrene–butadiene–styrene triblock copolymer without gelation

The conditions for the sulfonation of a highly unsaturated styrene–butadiene–styrene triblock copolymer (SBS) in cyclohexane containing a small amount of acetone with acetyl sulfate made by sulfuric acid and acetic anhydride without gelation were studied. After neutralization with metallic ions, the ionomers were characterized with IR spectrophotometry, dynamic mechanical analysis, and transmission electron microscopy. The melt flow, solution properties, and mechanical properties of the ionomers were studied. The results showed that gelation occurred during the sulfonation of SBS in cyclohexane at a 5–10% concentration without acetone, whereas in the presence of 5–10 vol % acetone, sulfonation proceeded smoothly without gelation. Transmission electron microphotographs of the lead ionomer indicated the presence of ionic domains. A dynamic mechanical spectrum showed the presence of three transition temperatures: ?82.9, 68, and 96.5°C. The melt viscosity of the ionomer increased with the sulfonate content. The melt viscosity of the different ionomers neutralized with different cations seemed to decrease with decreasing ionic potential for both monovalent cations and divalent cations The solution viscosity of the sodium‐sulfonated ionomer increased with increasing sulfonate content. The ionomer still behaved as a thermoplastic elastomer and showed better mechanical properties than the original SBS. The tensile strength of the different ionomers decreased as follows. For the monovalent cations, it decreased with decreasing ionic potentials: Li⁺ > Na⁺ > K⁺. For the divalent cations, it decreased with increasing ionic potentials: Pb²⁺ > Zn²⁺ > Mg²⁺. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1398–1404, 2005     

磺化丁苯橡胶离聚体与一些聚合物的熔融共混及产物性能

将磺化丁苯橡胶镁离子交联聚合体（简称离聚体）在增塑剂硬脂酸锌存在下分别与聚丙烯（ＰＰ）、高密度聚乙烯（ＨＤＰＥ）、丁苯嵌段共聚物（ＳＢＳ）、聚苯乙烯（ＰＳ）、顺丁橡胶（ＢＲ）在Ｂｒａｂｅｎｄｅｒ塑性仪密炼机中熔融共混，考察了共混比对平衡扭矩及物理机械性能的影响。结果表明，磺化丁苯橡胶镁离聚体与ＳＢＳ或ＰＰ共混，其拉伸强度呈协同效应，与ＨＤＰＥ共混呈加和效应，而与ＰＳ或ＢＲ共混则呈抵销效应。透射电镜     

Ionomers made from terpolymers with uniform poly(methyl methacrylate) grafts

Terpolymers with uniform poly(methyl methacrylate) (PMMA) grafts were prepared by terpolymerization of PMMA macromonomer, butyl acrylate, and acrylic acid in benzene using AIBN as initiator. During terpolymerization the macromonomer polymerizes faster than the monomers at the beginning but slower at the latter stage. The terpolymers were purified by solvent extraction and fractional precipitation. The average grafting number per chain of the terpolymers was determined to be 3–8. Ionomers were obtained by neutralization of the terpolymers with alkali hydroxide or metallic acetate. Dynamic mechanical spectrum of the ionomer shows the existence of two T_g's, which implies the occurence of microphase separation. The ionomer exhibits high damping over a temperature range from ?25 to 100°C. Both PMMA grafts and metallic carboxylate content raise the tensile strength of the ionomer and lower the ultimate elongation. The tensile strength of ionomers neutralized with different metallic ions decreases in the following order: Pb²⁺ > Zn²⁺ > Na⁺ > Ca²⁺ > Mg²⁺ > K⁺. The ionomers with uniform PMMA grafts show much better mechanical properties than the terpolymer without neutralization or the ionomer without PMMA grafts.     

Melt synthesis of sulfonated EPDM ionomers in batch and continuous processes

Zinc-neutralized sulfonated EPDM ionomers (Zn-SEPDM) were prepared by batch and continuous melt sulfonation processes, and the ionomer products were compared with ionomers synthesized by sulfonation of EPDM in homogeneous solution. The efficiency of a batch melt sulfonation using an intensive mixer as a reactor was comparable to that of the solution sulfonation process, but the efficiency of the melt sulfonation in a twin-screw extruder was considerably lower, which was thought to be a consequence of a relatively short reaction residence time due to limitations of the equipment. Melt neutralization was not complete, which produced a dark colored product. However, the incomplete neutralization and the color of the product did not affect the mechanical properties of the melt sulfonated ionomers, which were comparable to those of ionomers made by conventional solution sulfonation. The metal sulfonate concentration alone determined the mechanical properties of the ionomer. Melt sulfonation of Zn-SEPDM ionomers by batch or continuous melt processes appears to be a practical alternative to solution sulfonation, but further optimization of the melt sulfonation processes is needed to ensure uniform sulfonation and complete neutralization.     

充油及充填料的磺化SBR离子聚合体的性能

将自制的磺化丁苯橡胶离子聚合体（简称离聚体）在硬脂酸锌存在下于１６０～１７０℃在开炼机上与直链烃油及炭黑或超细ＣａＣＯ３混炼，并热压成型。考察了不同阳离子中和的离聚体的吸油率及直链烃油、炭黑或超细ＣａＣＯ３的填充量对离聚体力学性能的影响，以及对离聚体在Ｂｒａｂｅｎｄｅｒ密炼机上平衡扭矩的影响。结果表明，该离聚体填充５０％（质量，下同）左右炭黑及４０％左右直链烃油后其产物成为拉伸强度大于１４ＭＰａ、     

硫酸盐基离聚体的形态结构、力学性能及其共混

由环氧化（苯乙烯-丁二烯-苯乙烯）三嵌段共聚物（SBS）与硫酸氢钠水溶液反应制备了新型含硫酸盐基的SBS离聚体，研究了离聚体的形态结构、力学性能、离聚体时SI玛／氯醇橡胶（CHR）共混物的增容作用以及离聚体／聚丙烯（PP）共混物的力学性能。结果表明：在透射电镜下硫酸铅基离聚体呈现黑色圆柱状或四方晶形离子微区，硬脂酸锌作为离子增塑剂能提高钠离聚体的力学性能；随着离子基含量的提高，离聚体的拉伸强度及扯断伸长率增加；少量离聚体可以提高SBS／CHR共混物的力学性能，减小共混物的吸煤油率；扫描电镜图片显示二者的相容性增加；离聚体／PP共混物在拉伸强度与组成的关系方面呈现协同效应，并且其耐甲苯性能提高。