Rayleigh散射研究非相容聚苯乙烯／顺丁橡胶合金相结构

用光散射在线采集与分析方法完成了熔融混炼过程中非相容高分子共混物的形态结构分析。选择了聚苯乙烯／顺丁橡胶合金体系。使用了小角前向光散射和小角背散射（在线）技术，用Debye-Bueche光散射理论的结构参数如相关蹁ac、平均弦长l、平均旋转半径Rg和积分不变量Q表征了共混物中分散相尺度和均匀性。用扫描电子显微镜（SEM）测定了共混物中分散相尺寸，并与光散射的结果进行了比较。ac,l和Rg的变化规律与显微镜的结果是一致的。用积分不变量Q研究了共混物的均匀性。     

聚苯乙烯／顺丁橡胶合金相结构的X光小角散射研究

采用X光小角散射法研究了聚苯乙烯/顺丁橡胶合金体系的相结构及相容性。用Debye-Bueche光散射理论的结构参数，如相关距离ac．平均弦长l、旋转半径Rg和积分不变量Q等表征了合金中分散相的尺度及其分布在连续相中的均匀性，用扫描电子显微镜(SEM)定量测定了合金中分散相尺寸的大小和尺寸分布。结果表明：上述各光散射结构参数均可以在纳米尺度范围内表征合金体系的相结构，积分不变量Q可以表征合金体系相结构的均匀性。聚苯乙烯(PS)/颐丁橡胶(PB)合金是典型的不相容体系，无论PB还是PS处于稀相时均不呈现分子分散。     

聚苯乙烯改性顺丁橡胶性能的研究

利用动态部分硫化方法制备ＰＳ改性ＢＲ材料，研究了硫磺、ＴＭＴＤ、ＤＭ、白炭黑、软化油、ＰＳ等对共混材料性能的影响规律，优化得到最佳配方。     

聚丙烯／聚乙烯／顺丁橡胶三元共混物研究

本文研究了取乙烯种类及用量、顺丁橡胶用量、共混方式对聚丙烯／聚乙烯／顺丁橡胶三元共混物性能的影响。结果表明，LLDPE增韧效果优于HDPE。顺丁橡胶用量与共混物的缺口冲击强度成正比关系。采用PE与BR先制备增韧母料的二阶共混方式所得共混物的性能最佳。     

聚丙烯／聚乙烯／顺丁橡胶三元共混物研究

本文研究了聚乙烯种类及用量、顺丁橡胶用量、共混方式对聚丙烯／聚乙烯／顺丁三元共混物性能的影响。结果表明,ＬＬＤＰＥ增韧效果优于ＨＤＰＥ。顺丁橡胶用量与共混物的缺口冲击强度成正比关系。采用ＰＥ与ＢＲ先制备增韧母样的二阶共混方式所得共混物的性能最佳。     

聚氨酯／顺丁橡胶共混物结构与性能的研究

采用物理共混的方法,制备了廉价的ＢＲ和贵的热塑性聚氨酯（ＴＰＵ）共混物。利用电子拉力机,液变仪,动态粘弹仪,偏光显微镜和电子显微镜对力学性能、流变性能,动态粘弹性和形态结构进行了研究和分析。结果表明,ＢＲ和ＴＰＵ有较好的相容性,ＴＰＵ／ＢＲ共混物能达到使用要求,一些性能好于纯ＴＰＵ《     

预聚甲基丙烯酸甲酯／丁苯橡胶对聚苯乙烯基高聚物材料光散射性能的影响

以预聚甲基丙烯酸甲酯(MMA)/丁苯橡胶(SBR)为散射剂、聚苯乙烯(PS)为基体制备了高聚物光散射材料,研究了预聚MMA和SBR的添加量对高聚物材料光散射性能的影响.结果表明,当SBR为0.02%、预聚MMA为0.04%-0.08%时,可得到透光率不小于75%、雾度不小于80%的以PS为基体的高聚物光散射材料;预聚MMA的添加量与高聚物光散射材料的雾度呈现较强烈的振荡变化关系,和透光率之间的振荡变化关系略弱;sBR添加量和高聚物光散射材料的雾度之间呈现振荡变化关系,和透光率之间则没有明显的振荡变化关系.     

聚氨酯／聚苯乙烯互穿聚合物网络的结构与性能研究

通过改变组分比研究了PU/PS IPN结构与性能变化的规律。结果表明,在PU/PS为70/30时,电镜照片上呈现精细的细胞结构,相区尽寸缩小,网络间互穿程度最高,且溶胀度最低。热力学性能也同时出现最佳值,     

PS／LLDPE共混物光泽度的研究

用两步交联加工方法制备PS／LLDPE。采用二苄基山梨醇（DBS）作为LLDPE成核剂,在配方中加入LLDPE量的0.1％的DBS时,发现减小了LLDPE相的球晶尺寸,提高了PS／LLDPE的熔体指数,共混体的加工性能明显改善,使光泽度和力学性能均得到提高。     

环型聚苯乙烯结构与性能的研究

本文通过多种分析测试手段，详细研究了环型聚苯乙烯（ＲＰＳ）分子链结构、聚集态结构、热性能及稀溶液性质，并与线型聚苯乙烯（ＬＰＳ）作了对照。结果表明：ＲＰＳ链结构确为环状结构，由于链结构不同于ＬＰＳ，因此链刚性及其随分子量的变化关系也不同于ＬＰＳ，这是导致其性质与ＬＰＳ存在很大差异的根本原因。ＲＰＳ链堆积较ＬＰＳ松散，由于线团密度ＲＰＳ大于ＬＰＳ，所以宏观上二者比容并无多大差异，但ＲＰＳ比容受分子量影响较ＬＰＳ大。ＲＰＳ的Ｔｇ随分子量变化关系受自由体积和构象熵即链刚性两种因素的影响。动态光散射及小角Ｘ光散射实验结果说明，ＲＰＳ的扩散行为、流体力学半径和无扰分子尺寸与ＬＰＳ相比有很大不同。     

Blends of polypropylene with poly(cis-butadiene) rubber. I. Phase structure and morphology of blends

Pressed films of blends of polypropylene with poly(cis-butadiene) rubbers (PcBR) or grafted copolymer of ethyl acrylate (EA) onto PcBR (PcBR-g-EA) was examined by IR spectra, small angle X-ray scattering, small angle laser scatering (SALS), and scanning election microscopy (SEM). The problem of isomerization on PcBR (or PP/PcBR) is discussed by melt mixing (at a temperature of 180°C) using IR. X-ray scatering from the relation of phase was analyzed using Porod's law and led to the values of the interface layer of the blends. With increasing content of rubber, the interface layer thickness (σ_b) had a maximum value at 60/40 (PP/PcBR-g-EA) for the blends. The invariant (Q) was calculated and the relation of Q with σ_b was calculated using Debye-Buech statistical theory, and the average chord length (l) was obtained by Porod's definition of blends. The morphology and structure of the blends were investigated by SEM. The phase separation of the blends was found by SALS. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 2265–2272, 1997     

Crystallization Kinetics and Hydrophilicity Improvement of Biodegradable Poly(butylene succinate) in its Miscible Blends with Poly(ethylene oxide)

The spherulitic morphology and growth, overall isothermal crystallization kinetics and hydrophilicity of PBSU were investigated by POM, DSC and WCA measurements in its miscible blends with PEO. The Hoffman‐Lauritzen equation was employed to analyze the spherulitic growth rates of neat and blended PBSU, which show a crystallization regime transition between regime II and III. The overall crystallization rates of PBSU decreased with increasing crystallization temperature, regardless of blend composition, while the crystallization mechanism does not change. A significant improvement in the hydrophilicity of PBSU can be achieved by blending with different weight fractions of PEO, which may be essential for the practical application of PBSU/PEO blends.

     

New Miscible Poly(ether imide)/Poly(phenyl sulfone) Blends

Summary: Blends of PEI and PPSU were prepared directly during the plasticization step of an injection molding process throughout the full composition range. The molded blends were transparent and showed a single glass transition and no dispersed phase by SEM. These characteristics did not allow the presence of a single miscibilized phase to be inferred unambiguously due to the very similar T_gs and refractive indices of the two components of the blends. Miscibility was inferred after close observation of the position, height and area of the enthalpy relaxation peak of the 50/50 blend. The modulus of elasticity and yield stress changed linearly with composition, leading to polymer materials with intermediate characteristics. The linearity was attributed to the lack of decrease in free volume induced by mixing and to the similar orientation of the components before and after mixing. The PPSU presence only slightly reduced the known tendency towards brittle fracture of PEI under notched impact conditions, but the presence of a single amorphous phase led to an expected ductile behavior of the blends close to that predicted by the single rule of mixtures.

Break stress (?) and break strain (○) of PEI/PPSU blends as a function of composition.     

Fractional Crystallization and Phase Segregation in Binary Miscible Poly(butylene succinate)/Poly(ethylene oxide) Crystalline Blends: Effect of Crystallization Temperature

The effects of crystallization temperature of PBS (T_IC,PBS) on the fractional crystallization, phase segregation, and crystalline morphology of PEO in their miscible crystalline/crystalline blends are investigated. The crystallization kinetics and phase segregation of PEO are considerably influenced by T_IC,PBS. A higher T_IC,PBS results in the crystallization of PEO at an extremely large degree of supercooling and may facilitate the segregation of PEO within the interlamellar regions of PBS. At a high T_IC,PBS (e.g., 95 °C), the long period, thickness of amorphous and crystalline layers of PBS increase upon blending with PEO. The T_IC,PBS dependence of phase segregation of the PEO component is discussed from a thermodynamic as well as a kinetic perspective.

     

Surface Tension in Polymer Blends of Isotactic Poly(propylene) and Atactic Polystyrene

The surface tension of atactic polystyrene (PS), isotactic poly(propylene) (PP) and PS/PP‐blends, and additionally the interfacial tension between PP/PS have been measured in the temperature range between 200 and 280°C using the pendant drop method. Within the temperature range studied, the surface tension decreased linearly with increasing temperature for all systems whereas the surface tension of neat PP is approximately 7 mN/m smaller than the value of PS. The interfacial tension between PS and PP is in the range of approximately 4 mN/m and this indicates a strong incompatibility. It results a heterogeneous PP/PS blend morphology. A significant increase of the surface tension of the blends as a function of composition is observed only when the PS content exceeds 60 wt.‐%. Furthermore, microscopic observations indicate that even if the bulk matrix material is PS, a thin layer of PP can be detected by atomic force microscopy on the droplet surface used for surface tension measurements.     

等规聚丙烯/顺丁橡胶合金的结晶和抗冲击性能

研究了熔融共混法制备的不同共混比的等规聚丙烯(iPP)／顺丁橡胶(PcBR)合金的结晶特性及抗冲击性能。结果显示,随着(?)(PcBR)从0增至40％,iPP球晶的完整程度逐渐下降,球晶间的边界模糊化,球晶不断细化; PcBR的加入诱导了iPP的β晶型生成,其含量的增加导致合金中的微晶尺寸减小,晶面间距值基本不变,而长周期则明显增加;同时,合金的结晶峰所对应的温度有所升高,结晶速率明显增大,而相对结晶度减小,PcBR对iPP的结晶起到异相成核剂的作用;PcBR对iPP有显著的增韧效果。     

Non-Isothermal Crystallization of High-Impact Polystyrene/Poly(Phenylene Sulfide) Blends

The morphology of isothermally crystallized poly(phenylene sulfide) (PPS) and a blend combining it with high-impact polystyrene (HIPS) were observed through a polarized optical microscope equipped with a CSS450 hot-stage. The crystalline superstructure of PPS is mainly spherulite, and it was found that the presence of HIPS has little influence on the morphology of PPS, but decreases the nucleation rate of PPS. The effect of HIPS on the non-isothermal crystallization of PPS was investigated by differential scanning calorimetry (DSC). The maximum and onset crystallization temperatures for the HIPS/PPS blend were about 10°C lower than those of neat PPS, which indicates that the crystallization of PPS was retarded by HIPS. The Ozawa model was used to analyze the non-isothermal crystallization kinetics of PPS and its blends. The Avrami exponent values of neat PPS were higher than those of its blend, which shows that the presence of HIPS changed both the nucleation rate and the crystallization rate of PPS.     

Morphology and Photophysical Properties of Electrospun Light‐Emitting Polystyrene/Poly(p‐phenylene ethynylene) Fibers

Ultra‐thin fibers, consisting of blends of a PPE derivative and polystyrene, with average diameters ranging from 430 to 1 200 nm, were produced by electrospinning. The electrospinnability was significantly improved by adding pyridinium formate to the spinning solution. FT‐IR spectroscopy was used to confirm the composition of the electrospun fibers and their morphology was probed by SEM. The optical properties of the as‐prepared solutions, pristine and annealed fibers, and corresponding spin‐coated and solution‐cast films were investigated by UV‐vis spectroscopy. A comparison of the PL emission spectra revealed aggregation of PPE molecules in the electrospun materials but the extent of aggregation can be reduced if the materials are annealed above the glass transition temperature.