Volumetric and viscosity studies of interactions between sodium phosphate salts and poly(propylene glycol) 400 in aqueous solutions at different temperatures

Density and sound velocity at the 288.15–313.15 K and viscosity at the 298.15–313.15 K temperature range at 5 K intervals for polypropylene glycol (PPG) in aqueous solutions of sodium di-hydrogen phosphate, di-sodium hydrogen phosphate and tri-sodium phosphate with salt mass fractions 0.00, 0.010 and 0.020 are reported at atmospheric pressure. From the experimental density and sound velocity data, the apparent specific volume, excess specific volume, isentropic compressibility and isentropic compressibility deviation values have been determined. The infinite dilution apparent specific volume and isentropic compressibility values of PPG have been obtained and from which the infinite dilution apparent specific volumes of transfer of PPG from water to aqueous sodium phosphate solutions have been obtained for the investigated salt concentrations and temperatures. The excess specific volume, isentropic compressibility and viscosity deviation are negative and decrease in magnitude as temperature, concentration of sodium phosphate and charge on the anion of electrolyte increases.     

含季铵基离子交换纤维的制备研究

以辐射接枝丙烯酸(AA)后的聚丙烯(PP)无纺布(PP-g-AA)为基材,采用紫外引发的方法接枝甲基丙烯酰氧乙基三甲基氯化铵(DMC),建立了一种制备阴离子交换纤维的新方法,得到了PP-g-AA-DMC纤维.研究了丙烯酸接枝率、DMC浓度、溶剂种类、光照时间,浸泡时间等因素对DMC接枝率的影响,结果表明,DMC的接枝率随着丙烯酸接枝率、DMC浓度、光照时间和纤维浸泡时间的增加而增大.接枝前后纤维的红外光谱分析表明,DMC被成功接枝在PP-g-AA基材上.吸附性能测定结果表明,纤维对水中以阴阳离子存在的金属铬均具有较好的吸附性能.     

无卤阻燃聚丙烯研究进展

综述了目前应用于聚丙烯的铝-镁系阻燃剂、膨胀型阻燃剂、磷系阻燃剂、硅系阻燃剂改善其燃烧性能的研究成果,分析了无卤阻燃剂的加入对聚丙烯阻燃性能、力学性能的影响,总结了无卤阻燃聚丙烯尚待研究的科学技术问题,提出了研究新型无卤阻燃剂和不同阻燃剂复合的协效作用,研制新型表面改性剂和新的表面改性技术,使阻燃剂与聚丙烯有适宜的相容性,构筑适度柔性、结合力强的界面结构,是制备具有优良阻燃性能、力学性能的无卤阻燃聚丙烯努力方向的研究思路.     

Transmission electron microscopy study of phase morphology in polypropylene/ethylene-octene copolymer blends

Blends of polypropylene (PP) and ethylene-octene copolymers (EOC) were investigated by transmission electron microscopy (TEM) and by differential scanning calorimetry (DSC). The EOC contained 28, 37, 40 or 52 wt% of octene. Only the 50/50 PP/EOC ratio was used for all blends. None of the blends was fully miscible, there was always two-phase morphology. TEM observation followed by image analysis by ImageJ software revealed that the largest particles were in blend containing EOC-28 and the smallest were in blend with EOC-52. The coarsening rate at 200 °C was evaluated by TEM. The glass transition temperature (T_g) shift indicated partial miscibility. Partial miscibility was then confirmed by direct observation of bright PP lamellae in EOC dark phase.     

Modification of Interfacial Interaction of PBT/PP Blends by Adding Main-chain Liquid Crystalline Ionomer with Sulfonic Group

A main-chain liquid crystalline ionomer(MLCI)containing sulfonic group was synthesized by an interfacial condensation reaction.The MLCI was blended with polybutylene terephthalate(PBT)and polypropylene...     

Investigation on Properties of Polypropylene/Multi-walled Carbon Nanotubes Nanocomposites Prepared by a Novel Eccentric Rotor Extruder Based on Elongational Rheology

The properties of polymer matrix composites are related not only to the chemical composition of the materials but also to the processing equipment used for their preparation which has a direct influence on the microstructure of the composites. In this paper polypropylene (PP)/multi-walled carbon nanotubes (MWCNTs) nanocomposites were prepared by melt blending through a self-developed, eccentric rotor extruder (ERE). The structure and elongational deformation mechanism of an ERE were described in detail. The morphological, rheological, thermal and mechanical properties of the resulting PP/MWCNTs nanocomposites were investigated. Scanning electron microscopy (SEM) and rheological analysis showed that the MWCNTs were well dispersed in the PP matrix. The thermal stability was investigated by thermogravimetric analysis (TGA) and indicated that the addition of MWCNTs could effectively improve the thermal stability of pure PP. The percentage of crystallinity and tensile strength of the composites were improved as a result of the heterogeneous nucleation effect of the MWCNTs in the PP matrix. The research results revealed that the enhancement of the properties of PP/MWCNTs composites could be attributed to a better dispersion of the MWCNTs in the matrix as compared to samples prepared by conventional extrusion.     

Study on the toughening mechanism of PP/EVA dynamically crosslinked blend

The toughening mechanism of polypropylene (PP)/ethylene-co-vinyl acetate (EVA) dynamically crosslinked blend was investigated. The results indicated that dynamical crosslinking technology not only improved the interfacial adhesion between PP and EVA, but also increased the mechanical properties of PP/EVA blend. The quantitative and qualitative analysis of scanning electron microscopy (SEM) micrographs demonstrated that dynamical crosslinking technology could refine EVA particles in PP/EVA blend and promote the size distribution of EVA particles. The critical matrix ligament thickness of dynamically crosslinked and uncrosslinked blend was about 0.55 μm and 0.6 μm, respectively, indicating that the brittle-ductile transition occurred. Dynamic mechanical analysis (DMA) results illustrated that the tan δ peak of PP component in the dynamically crosslinked blend moved toward lower temperature compared with that of pure PP and the PP component in uncrosslinked blend; and the tan δ value of the dynamically crosslinked blend was higher than that of the uncrosslinked blend, which interpreted the toughening mechanism of dynamical crosslinking technology from the dynamic mechanical property of the blend.     

几种塑料的太赫兹光谱检测

利用太赫兹时域光谱技术测量了聚乙烯、聚丙烯、聚氯乙烯、聚四氟乙烯和丙烯腈-丁二烯-苯乙烯的太赫兹透射谱,研究其在0.2~2.6 THz频段的光谱特性,得到了在室温氮气环境下这些材料的太赫兹吸收谱和折射率色散特性.发现这五种塑料在太赫兹波段的折射率和吸收系数差异显著,折射率分别在1.35~1.85之间,聚乙烯、聚丙烯、聚四氟乙烯吸收很小,相比之下聚氯乙烯、丙烯腈-丁二烯-苯乙烯吸收很大,这为塑料种类的鉴别及高太赫兹透过率塑料衬底选择提供了依据.     

相变微胶囊改性UHMWPE复合材料的摩擦学性能

以石蜡为囊芯,蜜胺树脂为高分子囊壁材料,采用原位聚合法制备了相变微胶囊,并将其作为填料添加入超高分子量聚乙烯基体中,制得相变微胶囊改性UHMWPE复合材料.分析了该复合材料的硬度和物相组成,并研究了其在室温,低速和高速试验条件下的摩擦磨损性能.结果表明:微胶囊填料的加入可以起到较好的减摩降磨作用,填料的最适宜添加比例为20%,在低速试验条件下经改性的复合材料摩擦系数较纯UHMWPE降低60%以上,高速试验条件下改性后的复合材料耐磨性较之纯UHMWPE有明显提高,不同试验条件下材料呈现不同的磨损机理.     

茂金属催化丙烯间规聚合的研究进展

间规聚丙烯的结构独特新颖,具有良好的透明性、透气性以及耐辐射性等性能。由间规聚丙烯制成的共混材料,在医疗产品、包装和汽车配件等方面具有巨大的潜在用途。要得到性能优异的商品化间规聚丙烯,就需要在催化剂的选择性、催化剂负载化和聚合工艺等方面做深入研究。本文综述了间规选择性茂金属催化剂及其聚丙烯产品的研发进展,着重介绍了间规选择性茂金属催化剂的发展及其影响催化性能的因素,同时涉及间规聚丙烯的生产工艺以及间规聚丙烯产品的加工应用等方面。