SMA高级醇酯的合成及其对HDPE表面的改性

以苯乙烯-马来酸酐共聚物(SMA)为骨架,通过酯化反应,在SMA上接枝不同链长的高级脂肪醇侧链,制备了一系列大分子表面改性剂。将SMA及其高级醇酯化物与高密度聚乙烯(HDPE)进行共混,利用全反射红外光谱(FT-IR-ATR)及水接触角对共混体系的表面特性进行了研究。结果表明:在较低添加量范围内(w≤0.04),SMA的高级醇酯化物可以在HDPE薄膜的表面择优富集,可明显降低薄膜的水接触角,提高薄膜的表面能。     

添加型聚丙烯大分子表面改性剂PP-g-PEG的制备及其应用

以马来酸酐为桥联剂,通过其与单端羟基聚乙二醇的反应,合成了大分子表面改性剂聚丙烯-聚乙二醇接枝共聚物,探索了反应条件对接枝反应的影响,用IR、NMR、TGA、DSC对接枝物的结构及性能进行研究,并通过共混研究了接枝物对聚丙烯的表面改性效果.结果表明,提高马来酸酐接枝聚丙烯或聚乙二醇的分子量,会阻碍接枝反应的进行,接枝率明显下降;接枝聚乙二醇降低了接枝物的结晶能力;聚丙烯-聚乙二醇接枝共聚物的热稳定性随着聚乙二醇的含量增加及侧链聚乙二醇长度的增加略有下降;聚丙烯-聚乙二醇接枝共聚物组分在共混物中具有明显的向外择优迁移特性,可以作为聚丙烯的添加型表面改性剂使用.     

聚醚硅油表面迁移行为对聚苯乙烯表面极性的影响

利用变角衰减全反射傅立叶变换红外光谱(ATR-FTIR)法和接触角,分析了聚醚硅油在聚苯乙烯共混物薄膜表面的选择性富集行为及对其表面结构和表面极性的影响,认为接触介质的表面性质是影响共混物中各组分产生选择性迁移扩散的重要影响因素.强极性介质的诱导作用可以在共混物表面层中产生剧烈变化的浓度梯度,而弱极性介质所产生的表面浓度梯度比较缓和.     

通过熔体自由基反应调控聚丙烯体系的链结构和相结构

熔融反应加工是聚合物改性和制备聚合物纳米复合材料的重要途径之一.在此过程中,多数加成聚合物由于受到热、剪切或引发剂作用,通常可原位形成大分子自由基反应中间体.我们系统地研究了如何利用这类大分子自由基调控聚合物分子链的拓扑结构和聚合物纳米复合体系的相结构与界面.然而,某些聚合物大分子自由基,如聚丙烯(PP),受其分子链化学结构决定,在熔融反应条件下非常易于发生降解.研究发现,将可控自由基聚合中调控自由基反应活性的方法应用在熔融反应过程中可以显著抑制PP的降解,促进主反应的发生,在制备长链支化聚合物、调控聚合物纳米复合材料的相结构方面发挥了重要作用.本文介绍了本研究组近几年来通过熔体自由基反应调控PP体系的链结构和相结构的相关研究工作,如实现PP的长链支化,制备高熔体强度PP;在制备PP/C60 、PP/碳纳米管(CNTs)纳米复合材料过程中,利用熔体界面区域所发生的自由基反应,提高了纳米粒子与PP的界面相互作用,改善了纳米粒子在PP中的分散状态等.     

原位聚合法制备聚合物/纳米SiO_2复合材料的研究进展

纳米SiO_2改性聚合物制备的关键在于提高纳米粒子与聚合物基体的相容性及分散性;对纳米SiO_2进行不同的表面改性及选择合适的复合材料制备方法可以改变纳米粒子与聚合物基体的界面结合方式以及相容性和分散性,进而在不同程度上影响材料的性能.本文介绍了改性前后纳米SiO_2与聚合物基体的多种界面结合方式,对近年来利用原位聚合法制备聚合物/纳米SiO_2复合材料的研究现状和进展进行了综述.     

聚乙烯/聚乙二醇共混物中极性组分的表面富集

采用衰减全反射傅立叶变换红外光谱(FTIR-ATR)和扫描电子显微镜研究了极性组分聚乙二醇在聚乙烯／聚乙二醇共混物中的表面富集特性。研究结果认为不同组分表面自由能的差异以及聚乙烯基体的结晶异相排斥作用是导致聚乙二醇组分向共混物表面富集的主要驱动力，而极性组分相区的大小和分布则是影响其选择性迁移过程的重要因素。因此，可以通过添加合适相容剂的办法对聚乙二醇组分的表面富集程度进行有效的调控。     

聚合物辅助碳纳米管定向定位排列

探讨了聚合物对碳纳米管的不同表面修饰作用,总结了聚合物对碳纳米管的共价与非共价修饰方法,修饰后的碳纳米管在水溶液或不同极性有机溶剂、聚合物本体中的分散性得到了改善,更为碳纳米管的阵列化提供了前提.以碳纳米管的后排列为中心,主要综述了聚合物辅助下的碳纳米管垂直和水平方向上的定向排列方法,及近年来碳纳米管阵列化的研究进展,阐述了聚合物对碳纳米管的表面修饰及辅助碳纳米管实现阵列化的重要作用,提出了利用聚合物体系的自组织特性诱导碳纳米管自组装阵列化可以为实现单根碳纳米管的定向定位控制及纳米尺度功能器件的制备提供更多的可能.     

聚乙二醇表面改性抑制蛋白质非特异性吸附

聚乙二醇作为一种具有特殊亲水性和电中性的聚合物,被公认为抑制非特异性吸附的重要物质基础。本文综述了近年来利用聚乙二醇对各种用途的基质进行表面改性地研究,包括聚乙二醇本身的结构特点、聚乙二醇抵抗吸附的理论解释、在疏水性表面引入聚乙二醇改性的各种策略,并展望了其发展前景。     

高分子表面改性剂的分子设计

简述高分子表面改性剂对聚合物进行表面改性的微观模型，讨论了高分子表面改性剂的分子结构、分子量以及加工工艺条件对表面改性效果的影响，提出了高分子表面改剂的分子设计原则。     

氟碳端基聚合物合成及其表面吸附性能

综述了近十年来氟端基聚合物的合成,表征及其在表面吸附行为的研究成果。通过含有氟烷基的引发剂或终止剂在活性阴离子聚合反应或自由基聚合反应中使聚合物接上氟端基。已经成功地利用活性阴离子聚合反应合成了氟端基聚苯乙烯,通过含氟自由基引发烯类单体（如丙烯酸,乙烯硅等）可在相应聚合物链上引入氟端基,另外,聚合物的化学改性方法也可将氟基团接在聚合物链端（如氟基聚氧乙烯,氟端基聚合物具有的表面活性,当水溶液中或聚     

苯乙烯/甲基丙烯酸和苯乙烯/甲基丙烯酸(β-羟丙酯)嵌段共聚物的表面动态行为

通过测定表面动态接触角研究了两亲性的苯乙烯／甲基丙烯酸嵌段共聚物（ＰＳ ｂ ＰＭＡＡ）和苯乙烯／甲基丙烯酸（β 羟丙酯）嵌段共聚物（ＰＳ ｂ ＰＨＰＭＡ）的表面动态行为及温度、嵌段长度比等因素对其值的影响,讨论了聚合物表面当接触介质改变时链段或基团的再取向行为和表面性质     

两亲性嵌段聚醚酯在空气-水界面上的Langmuir单分子膜

聚醚酯是一种新型弹性材料,目前已成为工业化产品[1].对这种嵌段聚醚酯的合成和弹性行为[2]、熔体的流变性能[3]、以及纤维在拉伸状态下的聚集态结构和分子运动[4]已有一些报道.     

Two-dimensional self-assembly of linear poly(ethylene oxide)-b-poly(epsilon-caprolactone) copolymers at the air-water interface

The interfacial properties of amphiphilic linear diblock copolymers based on poly(ethylene oxide) and poly(epsilon-caprolactone) (PEO-b-PCL) were studied at the air-water (A/W) interface by surface pressure measurements (isotherms and hysteresis experiments). The resulting Langmuir monolayers were transferred onto mica substrates and the Langmuir-Blodgett (LB) film morphologies were investigated by atomic force microscopy (AFM). All block copolymers had the same PEO segment (Mn = 2670 g/mol) and different PCL chain lengths (Mn = 1270; 2110; 3110 and 4010 g/mol). Isothermal characterization of the block copolymer samples indicated the presence of three distinct phase transitions around 6.5, 10.5, and 13.5 mN/m. The phase transitions at 6.5 and 13.5 mN/m correspond to the dissolution of the PEO segments in the water subphase and crystallization of the PCL blocks above the interface similarly as for the corresponding homopolymers, respectively. The phase transition at 10.5 mN/m was not observed for the homopolymers alone or for their blends and arises from a brush formation of the PEO segments anchored underneath the adsorbed hydrophobic PCL segments. AFM analysis confirmed the presence of PCL crystals in the LB films with unusual hairlike/needlelike architectures significantly different from those obtained for PCL homopolymers.     

高分子表面活性剂P(AM-co-OPMA)的合成与表征

辛基酚聚氧乙烯醚(10)(OP-10)与马来酸酐在95℃下反应,合成了辛基酚聚氧乙烯醚马来酸单酯(OPMA);并在水溶液中与丙烯酰胺(AM)单体进行共聚合,获得了高分子表面活性剂P(AM-co-OPMA);考察了引发剂用量、单体组成、单体总浓度及反应温度对共聚物特性粘数与阴离子度的影响.通过红外光谱、紫外光谱、荧光发射光谱和电导滴定对共聚物结构和组成进行了表征;利用视频光学接触角测量仪分别测定了共聚物表面和界面张力.结果表明,在聚丙烯酰胺分子主链上引入OPMA链节后,不仅保持了PAM优良的增稠能力(特性粘数达764.31 mL/g),且赋予了共聚物较高的表面活性(浓度为1.5 g/L共聚物水溶液的表面和界面张力分别可达53.94 mN/m和5.41 mN/m).     

Surface segregation of polypeptide-based block copolymer micelles: An approach to engineer nanostructured and stimuli responsive surfaces

We describe the surface segregation of polypeptide-based block copolymer micelles to produce stimuli-responsive nanostructures at the polymer blend/air interface. Such structures were obtained by simultaneous surface migration and self assembly at the surface of diblock copolymer/homopolymer blends. We employed blends composed of homopolymer (PS) and an amphiphilic block copolymer polystyrene-b-poly(l-glutamic acid) (PS-b-PGA). The surface was functionalized based on the preferential segregation to the polymer blend/air interface of the hydrophilic PGA block of the diblock copolymer upon annealing to water vapor. The surface migration of the diblock copolymer to the interface was demonstrated both by XPS and contact angle measurements. As a consequence, the PGA interfacial attraction leads to a large surface excess on diblock copolymer which in turn, through macrophase and microphase separation, produced separated domains at the surface with regions composed either of homo or block copolymer. Herein we demonstrate that the use of asymmetric diblock copolymers with a higher content in PS lead to spherical micellar assemblies randomly distributed at the surface. As observed by AFM imaging the blend composition, i.e. the amount of block copolymer within the blend influences the density of micelles at the surface. Finally, when exposed to water, the pH affects the surface morphology. The PGA segments are collapsed at low pH values and extended at pH values above 4.8, thus inducing variations on the topography of the films at the nanometer scale.     

Reactively and physically compatibilized immiscible polymer blends: stability of the copolymer at the interface

This paper reports on the interfacial behaviour of block and graft copolymers used as compatibilizers in immiscible polymer blends. A limited residence time of the copolymer at the interface has been shown in both reactive blending and blend compatibilization by preformed copolymers. Polystyrene (PS)/polyamide6 (PA6), polyphenylene oxide (PPO)/PA6 and polymethylmethacrylate (PMMA)/PA6 blends have been reactively compatibilized by a styrene-maleic anhydride copolymer SMA. The extent of miscibility of SMA with PS, PPO and PMMA is a key criterion for the stability of the graft copolymer at the interface. For the first 10 to 15 minutes of mixing, the in situ formed copolymer is able to decrease the particle size of the dispersed phase and to prevent it from coalescencing. However, upon increasing mixing time, the copolymer leaves the interface which results in phase coalescence. In PS/LDPE blends compatibilized by preformed PS/hydrogenated polybutadiene (hPB) block copolymers, a tapered diblock stabilizes efficiently a co-continuous two-phase morphology, in contrast to a triblock copolymer that was unable to prevent phase coarsening during annealing at 180°C for 150 minutes.     

Influence of copolymer configuration on the phase behavior of ternary blends

The influence of copolymer configuration on the phase behavior of various ternary polymer blends containing a crystallizable polyester, a noncrystallizable polyether, and an acrylic random copolymer of different chain configuration was investigated. In these ternary blends, the acrylic random copolymer is typically added to control rheological properties at elevated temperatures. In fact, the acrylic random copolymers composed of various compositions of MMA and nBMA were found to have different miscibility with polyester as well as polyether, leading to substantially different phase behavior of ternary blends. Remarkable temperature dependence was also found. The mean-field Flory-Huggins theory for the free energy of mixing, extended to ternary polymer blends, was adopted for predicting phase diagrams where the exact spinodal and binodal boundaries could be calculated. Phase diagrams of ternary blends, predicted by the Flory-Huggins formulations and related calculations, were in good agreement with experimental phase diagrams. The differences observed in the rheological processes of various ternary blends with different acrylic copolymers were directly related to changes in miscibility, associated phase behavior, and chain configuration.     

Blends of a siloxane/urea/urethane-segmented copolymer with an IPDI-based polyetherurethane

A series of copolymer blends have been prepared using a poly(ether urethane) and a poly(siloxane–urea–urethane). The copolymers were prepared by a hardsegment first, two-step polymerization method. The hard segments of the copolymers were derived from isophorone diisocyanate (IP) and 1,4-benzenedimethanol (B), and the soft segments were based on polytetrahydrofuran (PTMO, M_w = 2000), and polydimethylsiloxane (PDMS, M_w =27,000), respectively. The siloxanecontaining copolymer, PDMS27K-IP-B2 (2 moles diol chain extender/mole PDMS27K), was used as the minor component (1.6, 2.5 and 6.0 wt%) in a series of blends. These blends were found to preserve the mechanical properties of the poly(ether–urethane) as well as the surface properties of the poly(siloxane–urea–urethane).     

Molecular design of multicomponent polymer systems. VII. Emulsifying effect of poly(ethylene–b–styrene) copolymer in high-density polyethylene/polystyrene blends

Poly(butadiene–b–styrene) copolymers containing a pure, 1,4-PB block have been synthesized by a “living” coordination process. The complete hydrogenation of the PB chain leads accordingly to a high-density polyethylene (HDPE) block. The emulsifying efficiency of such a copolymer (H-7) in HDPE/PS blends is compared with that of a previously reported poly(ethylene–butene–b–styrene) copolymer (SE-7) obtained by the PB hydrogenation of an anionically prepared PB–b–PS. Microscopy examinations demonstrate unambiguously the interfacial activity of both copolymers in HDPE/PS blends. The tensile mechanical properties of the blends are significantly but also differently modified by the two emulsifiers. The copolymer H-7 gives rise to the highest strengths, but, contrary to the copolymer SE-7, provides a poor ductility to the blends. This different behavior is assumed to result in part from the different characteristics of the hydrogenated PB blocks. The elastomeric HPB chain of SE-7 should form at the interface a more or less extended soft zone whereas a rigid interface would result from the cocrystallization of the HPB chain of H-7 with the HDPE homopolymer.