热塑性橡胶—磺化丁苯橡胶离聚体的性能及其共混

丁苯橡胶（SBR）作为高不饱和度的橡胶被成功地用硫酸乙酸酐作为磺化剂在石油醚及丁酮混合溶剂配成的溶液中磺化，并用乙酸盐中和成离聚体。研究了离聚体及其他聚合物的共混物的熔融流动及力学性能。结果表明，SBR离聚体能很容易在硬脂酸锌存在下熔融加工，其行为象热塑性橡胶，硬脂酸锌能降低布拉本特(Brabender)混和机的扭矩所表示的熔融粘度，并增加流动活化能和离聚体的拉伸强度。离聚体的磺酸基含量能增加熔融粘度及拉伸强度。用于中和的阳离子的种类明显地影响离聚体的性能。离聚与聚丙烯或SBS的共混物在拉伸强度上表现出协同效应，而它与聚苯乙烯或顺－1，4聚丁二烯则呈现抵消效应。     

氢化羧基丁苯橡胶离聚体的表征及其与聚乙烯共混

从氢化羧基丁苯胶乳出发，与钠、钾、锂、镁、锌和铅等金属离子中和，生成羧基丁苯离聚体胶乳。用IR，DSC，TEM对试样进行了表征，同时测定了不同离子中和及不同氢化度的离聚体物理机械性能，还将钾离聚体与聚乙烯以不同比例共混。结果表明，该离聚体既含有离子微区，又含有结晶微区；各种离聚体均呈现热塑性弹性体性能，其中铅及锂的离聚体拉伸强度最大；钾离聚体与聚乙烯以质量比为25／75-50／50共混时，试样拉伸强度呈现协同效应。     

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。     

乙烯/乙酸乙烯酯/甲基丙烯酸离聚体的合成、表征及性能

以乙烯/乙酸乙烯酯/甲基丙烯酸三元嵌段聚合物为基体合成了它的钠、锌盐离聚体。通过FT IR谱图以及DSC、TGA曲线证明了钠、锌离子与甲基丙烯酸发生了反应,玻璃化温度、熔点有提高;同时经过力学性能测试表明合成的离聚体在力学性能方面有改进。硬脂酸锌是离聚体的有效增塑、增强剂,离聚体的拉伸强度随着硬脂酸锌用量的增加而增加,其最大用量为30%。     

磺酸钠基苯乙烯-丁二烯-苯乙烯嵌段共聚物离聚体的力学性能及其应用

由环氧化苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)与NaHSO3开环反应合成了磺酸钠基SBS离聚体。研究了离聚体力学性能的影响因素、离聚体对SBS/氯醇橡胶(CHR)的增容作用、质量比对离聚体/聚丙烯(PP)共混物性能的影响。结果表明:硬脂酸锌能提高离聚体的力学性能;随着离聚体离子含量的增加,拉伸强度及扯断伸长率增加。加入少量离聚体,使离聚体/CHR共混物的力学性能提高,扫描电镜显示两者的相容性增加;离聚体与PP共混,在拉伸强度方面呈现协同效应。质量比各为1/1的离聚体增容SBS/CHR和离聚体/PP共混物的耐油性均较SBS大为改善。     

不同金属离子中和的新型硫酸盐基顺丁橡胶离聚体的合成、表征与性质

用环氧化顺丁橡胶在二氯乙烷中与硫酸氢钾、硫酸氢钠或硫酸氢锂水溶液以N,N-二甲基苯胺和四乙基溴化铵为催化剂进行反应,合成了新型的含硫酸钾、硫酸钠或硫酸锂基的顺丁橡胶离聚体,还用钾离聚体与醋酸镁、钙、钡、锌或铅溶液反应并洗涤,生成相应的离聚体。离聚体经纯化,用红外光谱（FTIR）及透射电镜表征,确定了硫酸盐基离子及其微区的存在。研究了开环反应的一些条件,结果表明,开环率可达到36％,该离聚体具有相当好的乳化性、一定的吸水性及耐油性,其吸水率和乳化性随离子电位的增加而增大,一价离子的吸水率及乳化体积比二价离子的大;稀溶液粘度随离子电位的增加而增大,二价离子的粘度比一价离子的大;其作为增容剂能增加SBS和氯醇橡胶的相容性。     

顺丁、丁腈橡胶离聚体改性聚氯乙烯研究

用马来酸酐接枝橡胶和金属离子交联形成离聚体的方法可提高顺丁橡胶(BR)、丁腈橡胶(NBR)、PVC三元共混物的相容性，以交联剂、引发剂、接枝单体为三要素，采用正交试验方法，通过综合评分法，优选了三元离聚体配方，在此基础上用部分硬脂酸锌代替无机氧化锌作离子交联剂，使合金材料获得了满意的性能，与未经改性PVC/BR/NBR三元共混物相比，硬脂酸锌离子交联马来酸酐接枝的三元合金的拉伸强度提高了101％，断裂伸长率增加113％，红外光谱证明了马来酸酐接枝顺丁胶与锌离子的离子交联的存在，且硬脂酸锌的效果优于氧化锌。     

含聚氧乙烯支链的三元共聚物及其离聚体

用聚氧乙烯（PEO）大单体与丙烯酸丁酯（BA）及丙烯酸（AA）共聚，合成了三元规整接枝共聚物，并经离子中和生成了离聚体。研究了共聚条件对各单体转化率及共聚物相对分子质量的影响。产物经纯化后用红外光谱仪，膜渗透压计，凝胶渗透色谱仪等进行了表征。研究了共聚物的平均接枝数，结晶度，力学性能及吸水性，还研究了丙烯酸质量分数，PEO质量分数，中和度及不同离子对离聚体力学性能的影响。结果表明，共聚开始大单体的转化速率大于小单体的，后期则相反。大单体转化率随引发剂用量增加而增加，随大单体占总单体的质量分数及大单体相对分子质量增加而下降，共聚物相对分子质量则随聚合时间增加而增加，随引发剂用量增加而降低。共聚物有一定结晶度及100％－200％的吸水率。三元共聚物中和成离聚体后拉伸强度明显增加，呈热塑性弹性体性质。铅或锌离子中和的离聚体拉伸强度最大。     

磺化SBS离聚体与结晶聚烯烃的共混物

研究了磺化SBS离聚体与聚丙烯或高密度聚乙烯在质量分数为10％的硬脂酸锌存在下熔融共混得到的共混物的力学性能。结果表明,共混物的拉伸强度均呈协同效应,这是因为生成了热塑性互穿网络结构。随着聚烯烃含量的增加,共混物由热塑性橡胶变成增韧树脂。     

顺丁烯二酸钾基(苯乙烯-丁二烯-苯乙烯)嵌段共聚物离聚体的力学性能及其应用

用环氧化(苯乙烯-丁二烯-苯乙烯)嵌段共聚物(SBS)开环反应合成了含顺丁烯二酸钾基的SBS离聚体,考察了离子基团不同含量对含顺丁烯二酸钾基的SBS离聚体力学性能的影响,研究了离聚体/聚丙烯(PP)共混物的力学性能和耐溶剂性能,以及离聚体对氯醇橡胶(CHR)/SBS共混物的增容效果。结果表明,该离聚体呈现热塑性弹性体行为;随着离子基团含量的增加,离聚体的拉伸强度及扯断伸长率增大,但当离子基团含量超过1.69mmol/g时,离聚体的力学性能又有所下降,离子基团最佳含量为1.23~1.69mmol/g;该离聚体与PP共混,在拉伸强度方面呈现协同效应;离聚体作为增容剂提高了SBS与CHR的相容性,当离聚体质量分数为3%时,力学性能达到最佳,共混物的耐溶剂性能也得到了改善。     

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,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     

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.     

Effect of zinc stearate on properties of melt processable ionomer based on sodium salt of sulphonated maleated EPDM rubber

Abstract

Sulphonation of maleated copoly (ethylen/propylen/diene), followed by its neutralisation by sodium hydroxide produces an ionomer containing both carboxylate and sulphonate anions on the backbone. Addition of zinc stearate lowers the melt viscosity of the ionomer, which is higher than the corresponding non-ionomer. Dynamic mechanical thermal analysis shows that zinc stearate acts as a low reinforcing filler under ambient conditions and as a plasticiser above 100°C (i.e. above the melting point of zinc stearate). For example, incorporation of zinc stearate causes an increase in storage modulus E′ at 25°C, but a sharp decrease in E′ at 110°C. Furthermore, the plot of tan δ v. temperature reveals that tan δ at the low glass–rubber transition temperature T _g decreases, while tan δ at the high temperature ionic relaxation temperature T _i increases in the presence of zinc stearate. Incorporation of carbon black lowers tan δat T _g and increases tan δ at T _i, thus strengthening the biphasic structure of the ionomer. The ionomer shows higher tensile strength and modulus than the corresponding non-ionomer. Addition of zinc stearate increases the tensile strength and elongation at break, with marginal decrease in modulus. Carbon black increases the stress–strain properties of the zinc stearate filled ionomer. Reprocessability studies of the ionomer filled with zinc stearate and carbon black show that the material can be recycled without a decrease in properties.     

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