掺铽聚丙烯薄膜的研究

合成了化学组成为Ｙ１－ｘＴｂｘＬ３和Ｌａ１－ｘＴｂｘＬ３（Ｌ＝Ｃ８Ｈ７Ｏ２）的两种荧光粉，将其掺杂到聚丙烯中，制得两种聚丙烯荧光薄膜，通过测试机械性能，微分扫描式量热法分析，紫外分光光谱和荧光光谱测定，研究膜的物理和荧光性能。结果表明：这两种掺铽聚丙烯膜在３６５或２５４ｎｍ紫外光激发下，都能发出黄绿色荧光。掺入Ｙ１－ｘＴｂｘＬ３的聚丙烯膜的荧光强度大于掺Ｌａ１－ｘＴｂｘＬ３的聚丙烯膜。     

新型聚丙烯基磺酸型阳离子交换膜的制备与膜体结构研究

以β晶型聚丙烯（ＰＰ）经双轴拉伸制备的新型聚丙烯微孔膜（Ａｓｐｏｒ膜）为基膜,采用浸吸法制血具有两相连续、贯穿的互穿聚合物网络（ＩＰＮ）为膜体结构的聚丙烯／聚（苯乙烯－二乙烯苯）磺酸型阳离子交换膜。应用ＳＥＭ、ＸＰＳ和ＷＡＸＤ手段,分析研究了ＰＰ基膜和离子交换膜（ＩＥＭ）的ＩＰＮ膜体结构及其力学性能的关系。     

金属螯合亲和膜吸附分离与纯化溶菌酶的研究（Ⅰ）——低温氧 …

用低温氧等离子体方法对聚丙烯微孔膜表面进行改性。扫描电镜,红外光谱和光电子能谱综合分析结果表明,膜表面上产生了－ＯＨ,－ＣＯＯＨ和Ｃ＝Ｏ等极性基团,这些基团可被活化和偶联制亲和膜。     

渗透汽化分离苯—乙醇混合物

以甲基硅橡胶及甲基丙烯酸十二酯－甲基丙烯酸异丁酯的共聚物共为膜材料，以聚丙烯睛多孔膜为底膜制成复合膜，对苯－乙醇混合物进行渗透汽化分离。考察了膜材料的组成、分离温度、原料液组分等因素对膜性能的影响。     

乙烯－丙烯共聚物磺酸盐离聚物的研究Ⅲ 离聚物的性质

考察了乙烯－丙烯共聚物磺酸钠离聚物的动态力学性能、力学性质和热稳定性等随离子含量的变化，讨论这些性质与离聚物结构的关系．另外，以离聚物为分离膜，用渗透蒸发方法进行乙醇－水混合液的分离，初步探讨了膜离子浓度、离子种类、实验温度和混合液组成等因素对该膜分离特性的影响。     

辐射增强PP／BR共混体系的力学性能

研究了在多官能团单体－三烯丙基异氰酸酯存在下，共混体系聚丙烯／１．４－聚丁二烯橡胶的辐射效应，用ＤＳＣ，动态粘弹谱对其进行表征。结果显示，三烯丙基异氰酸酯主要分布于聚丙烯／１．４－聚丁二烯橡胶共混物的界面自高能射线作用下，被引发参与界面反应，从而改善了共混体系的相容性，增强也界面粘接，提高了共混物的力学性能。     

壳聚糖水杨酸盐-明胶共混膜结构表征及其抗菌性

以溶液共混法成功制备出壳聚糖水杨酸盐－明胶共浊膜，用FT－IR、XRD、SEM表征了其结构，并测试了其吸水率，力学性能及抑菌性能。结果表明，壳聚糖水杨酸盐－胶胶共混膜中存在强烈的氢键相互作用及良好相容性，共混膜的力学性能随明胶含量增大而明显提高，当明胶含量为30％时，共混膜的抗张强度最大，其干、湿态抗张强度分别达99．9MPa和34．9MPa，比纯壳聚糖膜干，湿态抗张强度分别提高了99．8％有83．75，共浊膜抑菌性随明胶含量增加而下降，但其抑菌性仍明显高于壳聚糖膜。水杨酸的引入有利于改善其力学性能及抗菌性能，该共漫漫经膜作为一种潜在的伤口包扎材料，将具有广阔应用前景。     

聚丙烯微孔膜表面的空气等离子体处理

采用空气等离子体对聚丙烯微孔膜进行了处理，膜表面带有了氧元素，表面亲水性增强。微孔膜外表面改性程度较高，而孔内愈往深处改性程度愈弱。空气等离子体处理过的微孔膜力学性能下降。     

酸处理Silicalite—Ⅰ沸石填充硅橡胶渗透蒸发分离膜

研究酸处理Ｓｌｉｌｉｃａｌｉｔｅ－Ⅰ沸石对有机溶剂、水的吸附、脱附性质，酸处理Ｓｉｌｉｃａｌｉｔｅ－Ⅰ填充硅橡胶对低浓度有机溶剂水溶液的渗透蒸发分离性能以及填充膜的力学性能。实验结果表明，在硅橡胶胶膜中填充酸处理Ｓｉｌｉｃａｌｉｔｅ－Ⅰ沸石能改善膜对有机溶剂－水混合物的分离性能，且分离性能的改善与沸石在膜中的填充量以及硅橡胶的品种有关。另外，沸石的填充也有利于改善膜的力学性能。     

二乙烯三胺衍生物对纤维素膜的增塑作用

用Ｎ－（２－胺基乙基）－Ｎ－正辛基－１，２－乙二胺和Ｎ－（２－胺基乙基）－Ｎ－正癸基－１，２－乙二胺增塑再生纤维素膜，并用红外光谱，差热分析以及力学性能测量研究了增塑后膜的结构与性能，实验表明，上述二种化合物对纤维素膜有良好的增塑作用，Ｎ－（２－胺基乙基）－Ｎ－正辛基－１，２－乙二胺水溶性大，和甘油增塑的情况相似，用水浸泡后，增塑效果基本丧失；而Ｎ－（２－胺基乙基）－正癸基－１，２－乙二胺用水浸包     

金属螯合亲和膜吸附分离与纯化溶菌酶的研究(Ⅰ)──低温氧等离子体改性条件对亲和膜结构与吸附性能的影响

用低温氧等离子体方法对聚丙烯微孔膜表面进行改性.扫描电镜、红外光谱和光电子能谱综合分析结果表明,膜表面上产生了-OH、-COOH和C=O等极性基团,这些基团可被活化和偶联制亲和膜.所制备的Cu²⁺离子金属螯合亲和膜用于对溶菌酶的吸附,在20min和68W的最佳条件下,制成的亲和膜对溶菌酶的吸附量为8μg/cm².     

Hydrophilic modification of polypropylene ultrafiltration membrane by air‐assisted polydopamine coating

Coating by a mussel inspired polydopamine (PDA) is a simple and promising strategy to modify the hydrophilicity of polymer membrane surfaces. In this work, PDA coating was used to modify polypropylene (PP) ultrafiltration hollow fiber membrane. PDA coating parameters, ie, solution concentration and coating time were varied, and the effect of those parameters on membrane morphology, porosity, water contact angle, and pure water flux was investigated. In addition, air‐assisted PDA coating process was also conducted by channelling the air through PP membrane to avoid pore blocking and prevent water flux decline. The results showed that PDA coating successfully improved the hydrophilicity of PP membrane indicated by the decrease of water contact angle from 110° to 67° after coated by 3 g/L of PDA solution for 3 hours. The addition of air permeation on membrane lumen also increased pure water flux up to 511.2 L/m².h, a 270% increase from unmodified PP membrane. It might be associated to the pore blocking prevention that has been proven by SEM image and the membrane porosity that was increased about 4%.     

Boehmite-coated microporous membrane for enhanced electrochemical performance and dimensional stability of lithium-ion batteries

A heat-resistant boehmite-coated polypropylene (PP) membrane has been successfully fabricated and its potential application as a promising separator in the lithium-ion battery was explored. The boehmite powders with average sizes of 0.78, 1.03, and 1.72 μm, respectively, were used to fabricate the coated membrane. It was demonstrated that the coated membrane prepared by boehmite with a 0.78-μm size showed superior heat tolerance and proper air permeability. As compared to the commercialized PP membrane, such coated membrane presented improved electrolyte uptake, better interface stability, and enhanced ionic conductivity. In addition, the lithium iron phosphate (LiFePO₄)/Li cell using this composite membrane exhibited better rate capability and cycling retention than that using PP membrane owing to its facile ion transport and excellent interfacial compatibility. The coating layer showed an advantage on solid electrolyte interface film formation and greatly reduced charge transfer resistance. All these fascinating characteristics would boost the application of this composite membrane for high-performance lithium-ion battery.     

纳米碳酸钙/庚二酸复合成核剂对热致相分离法制备聚丙烯微孔膜的影响

以大豆油/邻苯二甲酸二丁酯(DBP)为混合稀释剂,采用热致相分离法(TIPS)制备聚丙烯(PP)微孔膜.研究了纳米碳酸钙成核剂、纳米碳酸钙/庚二酸复合成核剂对PP/大豆油/DBP(30/42/28,质量比)混合体系中PP结晶、熔融性能和PP微孔膜微观结构的影响.结果表明,单一纳米碳酸钙成核剂加入量为PP的0%~4%(质量百分率)时,PP/DBP/大豆油体系中PP熔融曲线上对应的峰值温度(Tpm)降到150.7~151.3℃,而纯PP的熔融峰值温度为165℃;DSC实验结果还显示加入1%~4%纳米碳酸钙和0.5%庚二酸后,导致PP的熔融曲线上出现了熔融双峰,说明纳米碳酸钙/庚二酸复合成核剂与单一成核剂相比有明显地促进β晶生成的作用,宽角X射线衍射(WAXD)实验进一步证实了β晶的存在.单一纳米碳酸钙成核剂对PP微孔膜的球晶结构和微观孔结构影响不大;加入纳米碳酸钙/庚二酸复合成核剂明显影响PP微孔膜的球晶结构和微观孔结构,其中0.5%庚二酸和1%纳米碳酸钙组成的复合成核剂制得的PP微孔膜的球晶结构明显,微孔膜孔径小且分布均匀;进一步增加纳米碳酸钙用量,PP微孔膜生成了许多细小的边界模糊的不规则结晶,微孔膜孔径不规则且尺寸较大,这与此时PP形成β晶结构有关.     

The effect of nucleating agents on the crystallization kinetics of polypropylene

Compositions of neat polyproylene (PP), PP–PE (polyethylene) blend and PP–PE–DBS (dibenzylidene sorbitol) were studied with respect to their crystallization kinetics by means of differential scanning calorimetry in isothermal mode. A modified Avrami equation was applied to obtain the crystallization parameters of PP, PP–PE and PP–PE–DBS. Optical and hot-stage microscopy and dynamical analysis were used for structure determination. Experimental results have indicated that PE addition inhibits PP crystallization rate and acts as a plasticizer, while addition of DBS changes the crystallization kinetics. A detailed study of the DBS nucleation effects indicates that owing to the high surface energy, nuclei are formed during primary crystallization, leading to a fine PP crystalline structure and improved mechanical properties.     

Photodynamic Efficiency of Protoporphyrin IX: Comparison of Endogenous Protoporphyrin IX Induced by 5-Aminolevulinic Acid and Exogenous Porphyrin IX

Abstract— Photodynamic efficiency of protoporphyrin IX (PP) accumulated in HeLa cells by the incubation of PP with HeLa cells was compared with that of accumulated PP formed from 5-aminolevulinic acid (ALA) as a precursor. The ALA-induced PP was photodynamically more efficient than exogenous PP. The difference is caused by monomelic PP concentration and PP localization site in HeLa cells. Exogenous PP was accumulated mainly in plasma membrane, and the membrane was strongly damaged by irradiation. The ALA-induced PP was selectively accumulated in mitochondria and inactivated the mitochondrial function by irradiation.     

Preparation,properties, and application of polypropylene micro/nanofiber membranes

Nanofiber membranes have huge potential applications in many areas due to their unique properties. However, the thermoplastic micro/nanofiber membranes were rarely reported. In this paper, polypropylene (PP) nanofibers were prepared by melt extrusion of immiscible blends of PP, cellulose acetate butyrate (CAB), and subsequent removal of the CAB matrix. The wet‐laid application was used to make PP nanofiber membranes and PP‐g‐MAH/nonwoven micro/nanofiber membrane. The properties of membranes including morphology, apparent density, porosity, contact‐angle, pore size distribution, and water flux were characterized. The results showed that the consequent membranes were provided with optimistic porosity and pore size distribution. Moreover, they were all with high pure water fluxes, which were superior to that of PP microporous membrane. They performed an excellent separation performance of TiO₂ suspension and dyeing wastewater. The work revealed this method could be an efficient one to make thermoplastic polymer micro/nanofiber membranes, and they would have a brilliant potential application for water treatment. Copyright © 2010 John Wiley & Sons, Ltd.     

Effect of Fumed SiO_2 on Pore Formation Mechanism and Various Performances of β-iPP Microporous Membrane Used for Lithium-ion Battery Separator

In this work, four samples containing different contents of fumed SiO_2 were prepared to improve the pore size distribution and various properties of b nucleated isotatic polypropylene(b-i PP) biaxial membrane used for lithium-ion battery separator. The wide-angle X-ray diffraction(WAXD) and differential scanning calorimetry(DSC) results show that the fumed SiO_2 promotes the formation of b-crystal slightly and narrows down the thickness distribution of b-lamellae; meanwhile, evenly distributed SiO_2 within b-i PP can be inspected by scanning electron microscopy(SEM). Moreover, further detailed characterization of morphological evolutions during biaxial stretching by tensile testing and SEM manifests that SiO_2 can strengthen b-i PP and make the samples deform more homogeneously, resulting in a gradually elaborate and finer oriented microfibril structure after longitudinal stretching, in which more uniform defects distribute between fibrils and restrain the formation of coarse fibrils effectively. Therefore, more superior microporous structure emerges with the addition of SiO_2, accompanied by narrower pore size distribution and better connectivity between microvoids, which is confirmed by mercury porosimeter and diminished Gurley value. Moreover, the lower thermal shrinkage, decreased shrinkage rate and suppressed porosity reduction indicate that fumed SiO_2 improves thermal and dimensional stability of membrane dramatically. Furthermore, due to the excellent wettability of SiO_2 with electrolyte, the microporous membranes doped with SiO_2 have higher electrolyte uptake, even after heat treatment at elevated temperature.     

Gas–liquid membrane contactors for CO2 removal

In the present work we use a membrane contactor for the separation of CO₂ from CH₄ and we systematically investigate the influence of both the type of membrane and the different process parameters on the overall process performance (permeability and selectivity). This work is important because it reports real process performance data (permeances and selectivities) for the total process consisting of absorption and desorption under practical conditions using feed mixtures. Commercially available porous PP hollow fiber membranes and asymmetric PPO hollow fiber membranes have been applied and MEA was used as absorption liquid in the membrane contactor. The proposed approach allows us to identify the operating window and potential of the process. Although the performance of the PP membranes outperforms the performance of the PPO membranes in terms of productivity and selectivity, the PP fibers are extremely sensitive to only small variations in the feed pressure, resulting in severe performance loss. In addition to that, extremely high liquid losses are observed for the PP fibers especially at elevated temperatures. Factors that are significantly reduced when asymmetric PPO membranes with a dense, ultrathin top layer are used, which thus improves the performance and significantly increases the operating window and potential of the membrane contactor process.     

Annealing of Oriented PP/PE Double-layer Film within the Melting Range of PE: the Role of Partial Melting and Self-nucleation

Due to the mechanical stability of the PP layer, the oriented PP/PE double-layer film with a row-nucleated crystalline structure can be annealed at a higher temperature than the PE monolayer film. In this work, the effects of annealing temperature within the melting range of PE on the crystalline structure and properties of PP/PE double-layer films were studied. When the annealing temperature is between 100 and 130 °C, below the melting point of PE, the crystallinity, the long period, lateral dimension and orientation of the lamellae in the PE layer increase with the annealing temperature due to the melting of thin lamellae and the self-nucleated effect of partially-melted melts during annealing. With the annealing temperature further increasing to 138 °C, near the melting ending point of PE, since the lamellae melt completely and the melt memory becomes weak during annealing, some spherulite structures are formed in the annealed sample, resulting in a decrease of orientation. In contrast, the annealing only causes the appearance of a low-temperature endothermic plateau in the PP layer. The improved size and orientation of lamellar structure in the PE layer increase the pore arrangement and porosity of the stretched PP/PE microporous membrane. This study successfully applies the self-nucleation effect of partially-melted polymer melt into the practical annealing process, which is helpful to guide the production of high-performance PP/PE/PP lithium batteries separator and the annealing process of other multilayer products.