间规聚苯乙烯合金

间规聚苯乙烯(sPS)是一种新型的结晶性工程塑料，与通用聚苯乙烯相比，具有结晶性能好，耐化学腐蚀性能优良等特点，因而具有较大的开发价值。本文总结了近十年来所报道的各种类型的sPS合金，包括sPS／弹性体合金，sPS／尼龙合金和sPS／聚酯合金，并对各种合金的力学性能和耐热性进行了详细论述。     

新型sPS/PA6/SsPS-H塑料合金的性能和形态结构

研究新型sPS PA6 SsPS H塑料合金的力学性能和微观形态结构 .间规聚苯乙烯 (sPS)的磺化产物磺化间规聚苯乙烯 (SsPS H)的加入明显地改善了sPS PA6(聚酰胺 6)二组分合金的力学性能 ,在sPS PA6 SsPS H重量组成为 80 2 0 5时 ,三组分合金的冲击强度最大 ,为 1 5 6kJ m2 ,约为纯sPS冲击强度的 3倍 DMA和SEM结果表明 ,SsPS H对sPS和PA6共混有良好的增容作用 ,它起到了降低合金的微相尺寸和加强相间界面粘结的作用 .此外 ,FTIR结果还表明SsPS H和PA6之间存在特殊相互作用 ,其作用方式是通过SsPS H的磺酸基将其质子转移给PA6酰胺基的氮     

双核单茂钛催化苯乙烯间规聚合反应

二十世纪八十年代,Ishihara等人首次使用钛/甲基铝氧烷(MAO)催化体系成功地制备了间规聚苯乙烯(sPS)[1].此后,由于sPS具有结晶速度快,熔点达270℃,赋予了sPS不同于一般聚苯乙烯的优良性能,因此研制新型的苯乙烯间规聚合催化剂成为国内外的研究热点之一.以往的研究主要集中于催化剂活性的提高,因为单核催化剂只是单一的活性中心,所以只能制备窄分子量分布(MWD)的sPS.近年来,为了提高sPS的加工性能和拓宽sPS的分子量分布,人们使用了不同的茂金属混合物[2,3]或者Z iegler-Natta催化剂的氢化物和单一的茂金属进行了诸多尝试[4,5].至今,…     

间规聚苯乙烯/等规聚丙烯/间规聚苯乙烯-b-聚(1-丁烯)共混体系相容性

间规聚苯乙烯(sPS)的改性主要是对其增韧改性,提高其力学性能.sPS的化学改性已有较多文献报道[1,2].     

填充间规聚苯乙烯的结晶

间规聚苯乙烯(sPS)性能取决于结晶行为与晶型,sPS结晶行为与形态有许多研究.本文重点综述了黏土、纳米CaCO3、滑石粉、SiO2、Mg(OH)2、TiO2,和成核剂等对sPS结晶行为、结晶形态、熔融特性与晶型的影响.认为sPS结晶行为与晶型取决于成核能垒.成核能垒低,有利于形成α-晶.熔融温度提高,提高成核能垒,有利于形成β-晶.填料加入阻碍sPS结晶成核,提高成核能垒,有利于形成β-晶.成核剂加入,降低成核能垒,有利于形成α-晶.     

磺化间规聚苯乙烯的表征

间规聚苯乙烯(sPS)是一种新型结晶性工程塑料,熔点达270℃,具有结晶速度快、耐热性好、耐化学腐蚀性优良等特点,可广泛用于汽车、电子、机械等行业,极具开发意义,但是由于sPS脆性大,抗冲击性差,故通过化学改性在sPS的苯环上引入极性基团,用于制成共混合金与复合材料,是提高材料韧性,开拓sPS用途的重要途径。     

模板表面对间规聚苯乙烯在纳米模板中结晶取向的影响

以偏振显微红外光谱方法研究间规聚苯乙烯（sPS）在阳极氧化铝（AAO）模板孔洞内的结晶取向行为。 以正己基三甲氧基硅烷修饰AAO模板孔洞表面,使其烷基化,探索表面性质对不同尺寸孔洞内sPS结晶取向的影响。 结果表明,sPS在255 ℃温度下结晶,而且随孔洞尺寸的减小,纳米孔洞内sPS分子链的垂直取向程度均降低,并且相同孔径尺寸下在表面烷基化的孔洞内sPS晶区分子链的垂直取向程度更低。 这些现象可归因于分子链与孔壁间相互作用的不同导致孔壁表面对晶核取向的诱导。     

sPS/PA6/SsPS-Zn塑料合金的研究

研究了磺化间规聚苯乙烯磺酸锌盐（SsPS-Zn)的增容作用以及sPS/PA6/SsPS-Zn三组分塑料合金的力学、热学性能和微观形态结构。结果表明：SsPS-Zn的加入明显地改善了sPS/PA6二组分合金的力学性能，在sPS/PA6/SsPS-Zn重量组成为80／20／5时，合金冲击强度最大，为14．2kJ/m^2。DMA和SEM结果表明，SsPS-Zn在合金中起到了降低微相尺寸和加强相间界面粘结的作用，可显著提高sPS和PA6两组分间的相容性，FTIR研究表明SsPS-Zn的磺酸锌基团和PA6的酰胺基之间存在相互作用。     

间规聚苯乙烯的化学改性

介绍了间规聚苯乙烯（sPS)的结构，特性和各种化学改性方法，包括在sPS侧链苯环上引入磺酸基，卤素等功能基因，在sPS分子链末端引入马来酸酐，丙烯酸酯等极性基因，与氢化丁二烯－苯乙烯热塑性弹性体（SEBS）形成接枝共聚物，及其与各类烯烃单体的共聚，对进一步拓宽sPs的应用领域具有重要意义。     

sPS/PET/SsPS-H共混体系的研究

以自制间规聚苯乙烯(sPS)功能化合成的磺化间规聚苯乙烯（SsPS-H)作相容剂,研究其对sPS/PET共混物微相结构与性能的影响,发现SsPS-H能够有效地改善二者的相容性,当sPS/PET/SsPS-H为85／15／2（重量比）时,冲击强度达到11．4kJ/m^2,为纯sPS的3倍,此时材料的弯曲强度为39．1MPa,下降约8％;DMA结果表明,随SsPS-H用量的增加,共混物的Tg逐渐提高;DSC分析结果表明,共混体系中sPS的熔点不受SsPS-H含量的影响,而PET的熔点在加入6份SpPS-H时明显降低。sPS在达到最大结晶速率的温度均随SsPS-H用量的增加先提而后下降。SEM观察到加入SsPS-H后,PET分散相的尺寸减小,且均匀程度增加,共混物室温下冲击断裂显著地由脆性转变为韧性,当加入6份SsPS-H后,冲击断裂又出现脆性。     

Syndiotactic Polystyrene / Fullerene Composites: Elucidation of Structural Aspect

Summary: Syndiotactic polystyrene (sPS), an attractive polymer due to its wide range of application, forms polymer-solvent intercalates with a large variety of solvent molecules ranging from liquids to solids. Recently, it has been realized that sPS intercalate prepared from SPS/naphthalene gel is more promising of making mesoporous materials. Here, the composite of sPS/fullerene have been prepared by taking advantage of sublimation of naphthalene. The different techniques as like XRD, SEM, HRTEM, FT-IR, DSC, TGA etc have been employed to characterized sPS/fullerene composite. XRD investigation shows the presence of δ form sPS in the composite. SEM and HRTEM reveal the fibrillar network with fringe like structure in presence of fullerene only and the average diameter of fibril has increased as compared to pure sPS fibrils. The conductivities of these fibrils have been increased with increasing amount of fullerene.     

Syndiospecific polymerization of styrene with embedded metallocene catalysts

Syndiotactic polystyrene (sPS) is a highly crystalline polymer with high melting point (270°C). The syndiospecific polymerization of styrene to sPS with metallocene catalysts is characterized by significant phase changes that lead to global gelation. Since sPS does not dissolve in styrene or solvents such as toluene and n-heptane, sPS precipitates out immediately from the liquid phase with the start of polymerization. The polymer crystallites aggregate to primary particles and they develop to a gel. The gelation is not due to cross-linking polymerization but due to strong molecular interactions between the polymer and monomer molecules. In this work, homogeneous Cp*Ti(OMe)₃ catalyst is heterogenized or embedded into sPS prepolymer particles. The embedded catalyst has been tested in a laboratory scale diluent slurry process to illustrate the feasibility of slurry phase polymerization for the synthesis of sPS particles.     

Reactive processing of syndiotactic polystyrene with an epoxy/amine solvent system

Syndiotactic polystyrene (sPS) is a new semi-crystalline thermoplastic which is believed to fill the price-performance gap between engineering and commodity plastics. In order to reduce the high processing temperature of sPS (>290°C), an epoxy-amine model system was used as a reactive solvent. Such a processing aid can be used to achieve a 50 to 500 fold lowering of the melt viscosity. When initially homogeneous solutions of sPS in a stoechiometric epoxy-amine mixture are thermally cured, Reaction Induced Phase Separation (RIPS) takes place, leading to phase separated thermoplastic-thermoset polymer blends. We focus our study on low (wt% sPS < 20%) and high concentration blends (wt% sPS > 60%) prepared by two processing techniques (mechanical stirring in a laboratory reactor or internal mixer/ reactive extrusion respectively). These blends have different potential interests. Low concentration blends (sPS domains in an epoxy-amine matrix) are prepared to create new, tunable blend morphologies by choosing the nature of the phase separation process, i.e. either crystallisation followed by polymerization or polymerization followed crystallisation. High concentration blends (sPS matrix containing dispersed epoxy-amine particles after RIPS) are prepared to facilitate the extrusion of sPS. In this case, the epoxy amine model system served as a reactive solvent. The time to the onset of RIPS is in the order of 7-9 min for low concentration blends, while it increases to 20-45 min for high concentration samples, as the reaction rates are substantially slowed down due to lower epoxy and amine concentrations. During the curing reaction the melting temperature of sPS in the reactive solvent mixture evolves back from a depressed value to the level of pure sPS. This indicates a change in the composition of the sPS phase, caused by (complete) phase separation upon reaction. We conclude that our epoxy amine system is suited for reactive processing of sPS, where final properties depend strongly on composition and processing conditions.     

Polymorphic behavior in syndiotactic polystyrene/clay nanocomposites

X‐ray diffraction methods were used in an investigation of the structural changes in syndiotactic polystyrene (sPS)/clay nanocomposites. sPS/clay was prepared by the intercalation of sPS polymer into layered montmorillonite. Both X‐ray diffraction data and transmission electron microscopy micrographs of sPS/clay nanocomposites indicated that most of the swellable silicate layers were exfoliated and randomly dispersed in the sPS matrix. The X‐ray diffraction data also showed the presence of polymorphism in the sPS/clay nanocomposites. This polymorphic behavior was strongly dependent on the thermal history of the sPS/clay nanocomposites from the melt and on the content of clay in the sPS/clay nanocomposites. Quenching from the melt induced crystallization into the α‐crystalline form, and the addition of montmorillonite probably increased heterophase nucleation of the α‐crystalline form. The effect of the melt crystallization of sPS and sPS/clay nanocomposites at different temperatures on the crystalline phases was also examined. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 736–746, 2002     

FTIR Spectroscopic Study of Crystallization of Uniaxial Drawn Syndiotactic Polystyrene/Carbon Nanotube Nanocomposite Films

The crystallization of uniaxial hot drawn syndiotactic polystyrene/multi-walled carbon nanotube (sPS/MWCNT) nanocomposite films was studied by FTIR spectroscopy. The effects of MWCNT content, draw ratio and drawing temperature on the sPS crystallinity were investigated. The sPS/MWCMT nanocomposite films show reduced crystallinities with the increase of MWCNT content. In addition, with the increase of draw ratio, both the pure sPS and the sPS/MWCNT nanocomposite drawn films exhibit increased crystallinity. The effect of drawing temperature on the sPS crystallization is complex. In a temperature range of 100―135 ℃, the crystallinity decreases with drawing temperature, whereas it increases at 140 ℃ for both pure sPS and its nanocomposite films.     

Morphological and Structural Studies of sPS/aPS Blends

Inrecentyears,thenewsedricrystallinepolymersyndiotacticp0lystyrene(sPS)hasat-ITactedmuchattentionduetoitsg0odchendcalresistanceandenhancedmechanicalperformanceatelevatedtemPeratUre.'H0wever,itexhibitshighbrittlenessandpoorimPact-resistanceandtCar-resistance.2Therefore,itisnecessarytomodifyitwithtougheningpolyIners.AsimPlemeth0dto0verc0methedriscibilityofatwo-phaseblendofsPSandatougheningpolymristotwrovetheinterfacialaffmity,wheretheadditionofablockcoP0lymerisconsideredtobemosteffective.3…     

Application of Fluorescence Depolarization Method to Monitor Free Volume in Gels of Stereoregular Polystyrene

Summary: A fluorescence depolarization technique was applied to get the information on free volume among polymer chains in gel form. Four fluorescent molecules with different molecular sizes were doped throughout the gels of syndiotactic polystyrene (sPS) and isotactic polystyrene (iPS) physical gel system, and their fluorescence anisotropy values were examined in detail for a range of polymer concentrations. Consequently, the free volume among sPS chains in sPS/chloroform gels is as large as the size of molecules smaller than 1,5-dimethylnaphthalene and is consistent with that of the cavity size in the δ-empty crystalline form of sPS solids. The cause to produce δ-empty crystalline form of sPS solids and to form cocrystals between sPS and guest molecules is discussed by comparing the molar size of guest molecules with the free volume among sPS chains in gel form.     

Effects of the oriented mesophase on the cold crystallization of syndiotactic polystyrene and its blend with poly(2,6‐dimethyl‐1,4‐phenylene oxide)

The effects of molecular orientation on the crystallization and polymorphic behaviors of syndiotactic polystyrene (sPS) and sPS/poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) blends were studied with wide‐angle X‐ray diffraction (WAXD) and differential scanning calorimetry. The oriented amorphous films of sPS and sPS/PPO blends were crystallized under constraint at crystallization temperatures ranging from 140 to 240°C. The degree of crystallinity was lower in the cold‐crystallized oriented film than in the cold‐crystallized isotropic film. This was in contrast to the case of the cold crystallization of other polymers such as poly(ethylene terephthalate) and isotactic polystyrene, in which the molecular orientation induced crystallization and accelerated crystal growth. It was thought that the oriented mesophase was obtained in drawn films of sPS and that the crystallization of sPS was suppressed in that phase. The WAXD measurements showed that the crystal phase was more ordered in an sPS/PPO blend than in pure sPS under the same annealing conditions. The crystalline order recovered in the cold‐crystallized sPS/PPO blends in comparison with the cold‐crystallized pure sPS because of the decrease in the mesophase content. The crystal forms depended on the crystallization temperature, blend composition, and molecular orientation. Only the α′‐crystalline form was obtained in cold‐crystallized pure sPS, regardless of molecular orientation, whereas α′, α″, and β′ forms coexisted in the cold‐crystallized sPS/PPO blends prepared at higher crystallization temperatures (200–240°C). The β′‐form content was much lower in the oriented sPS/PPO blend than in the isotropic blend sample at the same temperature and composition. It was concluded that the oriented mesophase suppressed the crystallization of the stable β′ form more than that of the metastable α′ and α″ forms during the cold crystallization of sPS/PPO blends. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1665–1675, 2003