相互缠结的聚甲基丙烯酸甲酯/磺化聚苯乙烯复合水基微乳液Ⅰ:制备及影响因素

将聚苯乙烯制成磺化聚苯乙烯离聚体 (SPS) ,利用相反转技术 ,将磺化聚苯乙烯离聚体加水制成具有纳米级的稳定的水基微乳液。利用SPS纳米微粒核内部作为反应场所 ,用引发剂引发亲油性单体甲基丙烯酸甲酯聚合 ,制备具有相互缠结结构的PMMA/SPS复合水基微乳液。研究了引发剂的用量、MMA的用量、溶剂极性对聚合反应及复合水基微乳液的影响     

磺化聚苯乙烯纳米纤维作为金刚烷胺固相萃取介质的研究

以电纺聚苯乙烯纳米纤维(PS NFs)为基底,通过磺化反应制得具有亲水性的磺化聚苯乙烯纳米纤维(SPS NFs),并通过静态和动态吸附实验考察其对金刚烷胺的吸附性能。据此建立了基于SPS NFs的固相萃取(SPE)法,并应用于动物源食品中痕量金刚烷胺的快速检测。结果表明,pH 4时,SPS NFs对金刚烷胺达到最优吸附,吸附动力学符合准二级动力学模型;优化SPS NFs的SPE条件(样液流速、洗脱条件等),结合超高效液相色谱-串联质谱(UPLC-MS/MS)检测鸡肉、鸡蛋、牛奶等样品中的金刚烷胺,2.0～20.0μg/kg加标水平的加标回收率为71.6%～87.5%,检测限为0.2μg/kg。与传统固相萃取法相比,本方法集分离、净化、浓缩功能于一体。     

炭黑填充聚苯乙烯熔体流变行为

研究了炭黑(CB)填充聚苯乙烯(PS)熔体的稳态和动态流变行为. CB/PS复合体系在CB体积分数φ=0.06时发生逾渗转变. 结果表明, 低应变区熔体模量降低主要归因于粒子-粒子及粒子-高分子间作用力的破坏, 高应变下模量的急剧下降则主要与高分子链间解缠结有关. 采用“两相”模型拟合线性动态流变行为, 发现应变放大因子A_f(φ)、填充相模量及松弛指数与温度有关. A_f(φ)~φ关系符合Guth方程和扩散控制的粒子簇聚集模型. “粒子相”形状参数与聚集体分维度均随温度升高而有所降低, 说明CB粒子聚集体因团聚而趋于各向同性, 应变放大效应减弱. “粒子相”特征模量G'_f1(φ)和G"_f0(φ)与φ关系满足标度律. 当φ > 0.06时, G'_f1(φ)和G"_f0(φ)及其标度指数均随温度升高而明显降低, 其G'_f1(φ)变化幅度略大于G"_f0(φ), 说明“粒子相”弹性与黏性组分具有不同的温度依赖性. 随着温度升高, 扩散控制的CB粒子团聚过程加快, 应变放大效应减弱.     

红外光谱法研究磺化间规聚苯乙烯离聚物离子间相互作用

采用红外光谱法研究了不同金属阳离子及水合作用对磺化间规聚苯乙烯 (SsPS)离聚物阴、阳离子间相互作用的影响 .实验结果表明 :离间相互作用的强弱可通过红外光谱表现出来 ,SsPS离聚物中磺酸根阴离子 (SO-3 )的红外吸收谱带与金属阳离子的性质及离聚物所处的环境有关 .在干燥状态下 ,SsPS离聚物中磺酸根阴离子 (SO-3 )由于受到金属阳离子静电场作用的影响 ,S—O键被极化而使其对称伸缩振动和不对称伸缩振动吸收峰移向高波数 ,移动的幅度与金属阳离子的性质有关 .离聚物吸水后 ,由于水合作用的影响 ,金属阳离子的极化作用减弱 ,因而使S—O键相应的对称伸缩振动和不对称伸缩振动吸收谱带移向低波数 .对于未中和的磺化间规聚苯乙烯 (SsPS H)样品 ,水合作用会使磺酸基团部分离解 ,产生磺酸根阴离子 (SO-3 ) .在干燥状态下 ,磺酸基团仍以—SO3H形式存在 ,红外谱图上出现—SO3H基团的特征吸收     

聚苯乙烯/银纳米粒子复合微球的合成及催化性能

首先通过乳液聚合和浓硫酸酸化制备表面富含磺酸根的磺化聚苯乙烯(PS)微球(直径532 nm),再用其静电吸附[Ag(NH_3)_2]~+离子,最后采用聚乙烯吡咯烷酮还原表面吸附的[Ag(NH_3)_2]~+离子,得到了负载银纳米粒子的PS/AgNPs复合微球.采用扫描电子显微镜、透射电子显微镜、紫外-可见光谱、红外光谱和X射线衍射表征了PS/AgNPs复合微球,并考察了其对甲基蓝(MB)的催化性能.结果表明,Ag纳米粒子高度分散在磺化PS微球表面;该PS/AgNPs复合微球对催化转化MB有较高的催化活性,并可多次重复利用.本研究在催化降解有机污染物方面有一定的实用价值.     

反相色谱法表征聚苯乙烯磺酸的转变现象

1969年,Smidsrφd和Guillet就应用反相色谱法(IGC)测量聚合物的玻璃化转变温度。十几年来许多科学工作者研究了IGC测量聚合物玻璃化转变现象的各种影响因素,但应用IGC研究离聚物还属罕见。离聚物分子上带有离子基闭,分子间的相互作用比较复杂,我们曾用热激放电电流法(TSDC)等测量了本实验所用的聚苯乙烯磺酸(PSSA)样品的玻璃化转变现象。应用IGC法,不仅能够比较精密地测出不同磺化度     

聚苯乙烯-b-聚丙烯酸/聚苯乙烯在水中的自组装及胶束尺寸的研究

利用动态光散射、透射电镜研究了嵌段共聚物聚苯乙烯 b 聚丙烯酸(PS b PAA)与均聚物聚苯乙烯(PS)在选择性溶剂水中的自组装行为.由于均聚物PS与PS嵌段具有相同的结构单元,均聚物PS参与胶束的形成,和嵌段共聚物的PS链段一同组成胶束的核;在适当的均聚物分子量和含量条件下,PS b PAA PS可以自组装形成单分散的纳米胶束;通过改变体系中均聚物PS的分子量和含量可在较大范围内调变胶束的尺寸.     

磺化丁基橡胶离聚体及其共混物的动态力学性质

<正> 含10％摩尔以下的离子且主链为柔性的离聚体是一种热塑性弹性体。在动态力学性质方面呈现特殊的行为,表现在贮能模量(1gE′)与温度的关系中有橡胶态平台出现。最早Otocka等指出,(丁二烯-甲基丙烯酸)共聚物无橡胶态平台,经金属离子中和后产生橡胶态平台,且E′增加。Agarwal,Makowski等则报道磺化乙丙胶离聚体的橡胶态平台随离子含量提高而加宽,随硬脂酸锌的加入而缩短。Fitzgerald及Weisst结合X-射线小角散射研究了甘油及邻苯二甲酸二辛酯对磺化聚苯乙烯离聚体的动态力学性质的影响。     

磺化聚苯乙烯纳米微球-聚丙烯酰胺杂化水凝胶的制备及性能

首先通过乳液聚合法合成了聚苯乙烯(PS)微球,该微球经浓硫酸磺化后得到了磺化聚苯乙烯(SPS)微球;然后将合成的SPS微球作为多功能交联点加入丙稀酰胺(AAm)化学水凝胶网络中制备了SPS-PAAm杂化水凝胶。通过扫描电镜、透射电镜观察了SPS微球及杂化水凝胶的微观结构。研究了SPS微球对SPS-PAAm杂化水凝胶的凝胶分数、溶胀性能和力学性能的影响。结果显示:随着SPS微球用量的增加,SPS-PAAm水凝胶的凝胶分数先增加后降低,平衡溶胀度降低;SPS微球的加入能改善水凝胶的力学性能,随着SPS含量的增加,水凝胶的拉伸强度和能量损耗增加;SPS微球和PAAm分子链间存在物理相互作用。     

加工工艺对气相生长碳纤维填充聚苯乙烯复合体系导电逾渗与动态流变特性的影响

研究了加工工艺对气相生长碳纤维(VGCF)填充聚苯乙烯(PS)复合体系导电逾渗与动态流变特性的影响.结果表明,低转速、短时间混合有利于VGCF形成较为完善的逾渗网络结构,其复合体系逾渗阈值低、导电性能好.使用作者提出的两相模型描述VGCF/PS复合体系的流变特性,发现低转速、短时间(30 r/min、5 min)混合条...     

磺化聚苯乙烯镧离子型聚合物的稀溶液性质

聚电解质行为;比浓粘度;电解质;磺化聚苯乙烯镧离子型聚合物的稀溶液性质     

Structure and properties of dynamically cured EPDM and ionomer blends

The structure and properties of dynamically cured ethylene-propylene-diene terpolymer (EPDM) and ionomer blends have been studied. The blends were prepared in a laboratory internal mixer, where EPDM was cured under shear in the presence of ionomer with dicumyl peroxide (DCP) under different shear conditions. The effects of EPDM/ionomer compositions, DCP concentration and the intensity of shear mixing were investigated using capillary rheometer, differential scanning calorimeter (DSC) and scanning electron microscopy (SEM) techniques. Two kinds of poly(ethylene-co-methacrylic acid) ionomers containing different metal ions(Na⁺ and Zn⁺⁺) were compared and the effect of the metal ion type for neutralization was considered. The Zn-neutralized ionomer showed better miscibility with EPDM than the Na-neutralized ionomer. It is concluded from the rheological properties, crystallization behavior and morphology that the dynamically cured EPDM and Zn-ion ionomer blends show the behavior of a thermoplastic interpenetrating polymer network (IPN).     

Preparation and characterization of microcellular polystyrene/polystyrene ionomer blends with supercritical carbon dioxide

The preparation of microcellular polystyrene (PS), lightly sulfonated polystyrene (SPS), zinc‐neutralized lightly sulfonated polystyrene (ZnSPS), and blends of PS/SPS and PS/ZnSPS via supercritical CO₂ was carried out with the pressure‐quench process. Both higher foaming temperature and lower pressure result in larger cell sizes, lower cell densities, and lower relative density for microcellular ionomers and blends as for microcellular PS. The difference among various microcellular samples is the change of cell size with the sample composition. The cell size decreases in the sequence from SPS, through PS/SPS blends, PS and PS/ZnSPS blends, to ZnSPS. The diffusivity of CO₂ in samples also decreases in the sequence from SPS, through PS/SPS blends, PS and PS/ZnSPS blends, to ZnSPS. For this series of samples with similar structure and identical solubility of CO₂, the varying diffusivity is responsible for the difference of cell sizes. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 368–377, 2003     

Self-assembly of Sulfonated Polystyrene Ionomers in Chloroform

Light scattering and electric birefringence were used to determine the dimensions and extent of aggregation of dilute solutions of sodium sulfonated polystyrene ionomers with sulfonation levels of 0.5, 1.35, 2.6 and 5.8 mol% in chloroform. It was found that in solutions of ionomers with sulfonation level 1.35 and more the equilibrium between single chains and aggregates consisting of two and more chains is observed. These data were analyzed using the “open” association model. It was shown that an increase in the sulfonation level of ionomers results in a decrease in the hydrodynamic radius of single chain. On the other hand, it was established that an increase in sulfonation level leads to increase in the size of aggregate consisting of two chains. More pronounced expansion of ionomer chains incorporated into aggregate was found for ionomers with high sulfonation level.     

Deformation and fracture behavior of polystyrene ionomer and ionomer blends

The deformation and fracture behavior of sulphonated polystyrene ionomers, and of blends of these with polystyrene have been investigated. The microstructure of the ionomer, which varies with ion content, appears to have a significant effect on mechanical properties. Both tensile strength and toughness increase appreciably at ion contents near 5 mol%, where clusters become dominant over ion pairs and multiplets. In blends of the ionomers and polystyrene, phase separation occurs and the ionomer component appears in the form of fine particles dispersed in the polystyrene matrix. These particles possess a greater effective entanglement density than the matrix, as a result of ionic crosslinking, and they provide reinforcement against early craze breakdown and fracture. Tensile strength and fracture energy increase rapidly as the ionomer concentration in the blend is increased and they become essentially independent of blend ratio above about 10 wt% of the ionomer. Tests carried out on thin film specimens of the blends show that the dispersed ionomer particles adhere well to the matrix and contribute to the fracture energy both by inducing matrix crazing and by internal fibrillation within the particles.Dedicated to Professor Hans-Henning Kausch on the occasion of his 60th birthday.     

Effect of ionomers on mechanical properties, morphology, and rheology of polyoxymethylene and its blends with methyl methacrylate-styrene-butadiene copolymer

Two ionomers, ethylene-methacrylic acid copolymer ionized with sodium cation (EMA-Na) and zinc cation (EMA-Zn), were employed as impact modifiers to prepare blends with polyoxymethylene (POM) via a melt extrusion. A copolymer of methyl methacrylate-styrene-butadiene (MBS) used as a co-impact modifier was also incorporated into the blends. The mechanical properties, thermal properties, morphology, and rheology were studied. A moderate toughening was observed for POM/ionomer binary blends, which was attributable to the rubbery natural and good adhesion of the ionomers. EMA-Zn exhibited a much better toughening effect than EMA-Na because of its higher elasticity and stronger interaction with POM. The incorporation of the ionomers into POM/MBS blends resulted in an improvement of mechanical properties, which was attributable to the compatibilizing effect of ionomer on POM/MBS blending system. The observation of scanning electron microscopy demonstrated that the finer phase domains were caused by incorporation of ionomers, which, acting as a compatibilizer as well as an impact modifier, reduced the interfacial tension and improved the interfacial adhesion between the phases. Differential scanning calorimetry investigation indicated that the presence of ionomer in the blends disturbed the crystallization of POM and resulted in a decrease in the crystallinity of POM. The evaluation of melt flow index revealed an increase in viscosity of the blends by incorporation of the ionomers, which was caused the ionic interaction between POM and the ionomers.     

Thermorheological studies on polymeric blends

Two petroleum-derived aromatic hydrocarbon resins (HRs) were blended (1:1) with expanded polystyrene (EPS) waste and small amounts (up to 10 mass%) of poly(vinyl chloride) (PVC) to increase both the lustrous carbon (LC) yield and softening point of the blends without any deterioration of their rheological characteristics. The blends were prepared and tested for LC content, softening points, shear stress and apparent viscosity to check their applicability as LC precursors under industrial conditions. The properties of polystyrene compositions with bitumen fractions depend primarily on composition and viscosity of oil fraction. Additional modification by poly(vinyl chloride) improves the blends’ properties, like bright coal content, softening point and viscosity, and opens new possibilities of plastics’ wastes utilization.     

Synthesis of Maleated Ionomers via Ring‐Opening Reaction of Epoxidized (Styrene‐Butadiene‐Styrene) Triblock Copolymer with Potassium Hydrogen Maleate and Study of their Properties

A novel method for synthesizing maleated ionomer of (styrene‐butadiene‐styrene) triblock copolymer (SBS) from epoxidized SBS was developed. The epoxidized SBS was prepared via epoxidation of SBS with performic acid formed in situ by 30% H₂O₂ and formic acid in cyclohexane in the presence of polyethylene glycol 600 as a phase transfer catalyst. The maleated ionomer was obtained by a ring‐opening reaction of the epoxidized SBS solution with an aqueous solution of potassium hydrogen maleate. The optimum conditions for the ring‐opening reaction and some properties of the ionomers were studied. It is necessary to use phase transfer catalyst, ring‐opening catalyst and a pH regulator (dipotassium maleate) for obtaining the epoxy group conversion over 90%. The product was characterized by FTIR spectrophotometry and transmission electron microcroscopy (TEM) to be an ionomer with domains of maleate ionic groups. With increasing ionic groups, the water absorbency and the dilute solution viscosity of the ionomer increase, whereas the oil absorbency decreases. The tensile strength and ultimate elongation of ionomers increase with ionic group content and are higher than those of the original SBS without using any ionic plasticizer, which is usually used with the sulfonated ionomer. The ionomers with 1.2–1.7 mmol ionic groups/g exhibit optimum mechanical properties and behave as thermoplastic elastomers. The ionomer can be used as a compatibilizer for the blends of SBS with oil resistant chlorohydrin rubber (CHR). Addition of 3 wt% ionomer to the blend can increase the tensile strength and ultimate elongation of the blend optimally. The compatibility of the blends enhanced by adding the ionomer was shown by scanning electron microscopy (SEM). The blend of equal weight of SBS and CHR compatibilized by the ionomer behaves as a toluene resistant thermoplastic elastomer.     

嵌段离聚物的缔合和络合行为(Ⅲ)──基于SEBS的嵌段离聚物和含吡啶基聚合物间的相互作用

制备了一系列基于氢化SEBS的嵌段离聚物(BCI),研究了具有不同金属对应离子的BCI分别和含聚乙烯吡啶基的无规共聚物MVP和SVP的共混物的溶液粘度和本体的热行为.结果表明,MVP和SVP可与BCI的PS离子化嵌段形成络合物,导致T_g增加且远高于FOX方程预示值,同时比浓粘度远高于加合性预示值.在所研究的金属离子中,Ni和Cu显示最佳的络合能力.     

Structure of ionic aggregates of ionomers. II. Effect of humidity and temperature on ethylene and styrene ionomers

Small‐angle X‐ray scattering profiles of ethylene and styrene ionomers were studied to clarify the structure of ionic aggregates as a function of humidity or temperature. The intensity and position of ionic cluster peaks were observed for ionomers with a certain degree of neutralization. The intensity of the ionic cluster peak for the ethylene ionomer increased with increasing relative humidity, but it decreased for the styrene ionomer. With increasing humidity, the position of the ionic cluster peak shifted to smaller angles for both ionomers. The size of the ionic aggregates and the closest approach distance between the aggregates were analyzed, and the results varied with humidity for both ionomers. The size did not vary markedly with a change in temperature, whereas the closest approach distance and number of ionic aggregates changed slightly with the melting temperature of the ethylene ionomer and the glass‐transition temperature of the styrene ionomer. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 831–839, 2002