嵌段共聚物增容剂对不相容均聚物共混体系相行为和界面性质的影响

聚合物共混体系(又称聚合物合金)兼具其相应组分的均聚物和共聚物的多种特征,甚至具有新的理想性能,从而成为了一种具有极高经济价值的新材料.该材料的研发极大地丰富了高分子物理学、高分子化学和材料学的研究内容,拓宽了聚合物材料在现代工业中的应用,同时把聚合物材料研究推向了交叉科学的前沿.均聚物/嵌段共聚物/均聚物体系作为经典的三元聚合物共混体系,对其进行深入地研究,不仅可以促进人们对高分子科学中重要问题的理解,而且可为新型嵌段共聚物增容剂的改良和设计提供理论依据.近年来,有关聚合物共混体系的实验、理论和计算机模拟工作很多,并且取得了较大的进展,但是相关综述较少.本文以均聚物/嵌段共聚物/均聚物体系为例,综述该领域的基本概念和发展历史,并着重介绍两嵌段共聚物增容剂对该三元共混体系相行为和界面性质的影响.此外,还介绍了这一领域的关键科学问题、发展前景和研究方向.     

共混型高分子梯度材料的研究进展

共混型高分子梯度材料具有综合性能好、制备更简便等优点,近年来备受研究者的关注.本文综述了近十年来共混型高分子梯度材料的研究进展.介绍了在溶液体系、熔融体系、乳液体系中通过共混方法构筑高分子梯度材料的制备方法,如溶解扩散法、电场诱导法、温度梯度法等.对在不同共混体系中预测聚合物组分的分散相或组成形成梯度变化的相关理论进行了评述,分析了影响梯度相结构形成的各种因素,并进一步分析了共混型高分子梯度材料的发展方向和研究重点.     

形状记忆高分子材料的新型共混制备方法

形状记忆高分子材料(shape memory polymers,SMPs)作为一种特点突出、性能优良的智能材料具有极高的研究和实用价值,受到各国研究人员的广泛关注,新的制备方法和材料体系不断涌现,显示出巨大的发展潜力.本文总结了近年来出现的以共混方式为基础的多种重要制备方法,包括聚合物与聚合物直接熔融共混、溶液共混、借助增容剂或交联剂进行共混、通过新型微层共挤出技术进行交替层状共混、以及利用静电纺丝技术进行三维网络结构共混等.相较于化学合成方法,这些共混方法具有操作简单、原料易得、制备效率高、产品性能调节方便、制备过程更为环保等优点,并且能够得到与化学合成方法性能相同甚至更好的产品,优势突出,是今后制备形状记忆高分子材料的一大趋势.本文从这些新型共混材料的制备过程、微观结构、形状记忆性能等角度详细分析了不同方法的特点和优势.这些近年来出现的共混制备方法对于形状记忆高分子材料的发展和未来应用将是至关重要的.     

高分子复杂体系的结构与流变行为

流变学测试对非均相体系的结构变化具有敏感响应,被认为是表征多相/多组分聚合物体系结构与性能极为有效的方法.本文主要依据作者及其合作者的工作,对近年来围绕非均相体系形态结构与流变响应所开展研究的最新结果进行了总结和评述,涉及LCST型高分子共混体系的相形态与黏弹松弛、嵌段共聚物的微结构与线性/非线性黏弹行为、聚烯烃剪切诱导结晶时间尺度与流变响应、填充聚合物体系的结构性能和流变行为.对多相/多组分高分子共混体系形态结构演变的特征流变响应的充分认识,将有助于优化非均相体系的形态结构与最终力学性能.     

结晶行为对无定型/结晶聚合物共混体系形状记忆性能影响的研究进展

形状记忆聚合物因其具有质轻、低耗、形变量大、回复率高、形状可调、刺激方式多样等众多优点而受到广泛关注。相较于其它类型的形状记忆聚合物而言,共混型形状记忆聚合物的制备则更为简单方便。目前最常见的共混型形状记忆材料是无定型/结晶聚合物体系,其中结晶聚合物的结晶行为是影响整个体系形状记忆性能的关键。本文结合了该领域的研究现状,就结晶度、晶体尺寸以及晶体取向对共混体系形状记忆性能影响的研究进展进行了综述。     

PEO/PVAc共混体系辐射交联反应中溶胶分数与辐照剂量间的关系

交联度对由聚合物共混物辐射交联而制备出的材料的性能影响很大,研究共混体系的辐射交联度和交联行为是十分重要的。通常,用溶胶分数与辐照剂量间的关系表征聚合物的交联度和交联行为。文献[2]发现线性聚合物的溶胶分数与辐照剂量间的关系与高分子链结构参数有关。本文试图考察共混体系的辐射交联行为是否也与高分子链结构有关,并将线性聚合物的关系式(1)推广应用到PEO/PVAc共混体系中。目前,有关这方面的研究工作还未曾见文献详细报道。     

粒子-聚合物相互作用与粒子-粒子相互作用对聚合物基纳米复合物力学性能的影响

聚合物基纳米复合物(PNCs)具有比传统高分子材料更加优异的光学、力学、热力学等性能,广泛应用于各个工程领域.而纳米粒子(NPs)对材料性能提高的机理则是当前聚合物纳米复合物领域研究的重要问题,聚合物纳米复合体系相互作用的影响因素众多,至今尚未明确并完整建立复合体系相互作用与性能增强之间的关系.本文总结了近年来关于纳米粒子填充聚合物基体力学性能的研究,从粒子-聚合物相互作用和粒子-粒子相互作用角度阐述了聚合物纳米复合体系力学性能的增强机理,并根据体系中不同的结构关系分别总结了聚合物/未改性纳米粒子复合体系和聚合物/聚合物接枝纳米粒子复合体系中影响力学性能的因素.该部分内容具有重要的理论和实践意义,有助于构建复合体系微观结构与宏观性能之间的关系,进而对微观层面调控PNCs的力学性能提供指导.     

共轭高分子材料荧光颜色的调节机理及方法

近年来,共轭高分子作为荧光材料的研究受到越来越多的关注.共轭高分子相对于小分子发光材料在材料加工和发光性能上均具有极大的优势,从而在生物成像、传感、编码和光电材料等方面均有良好的应用前景,而其发光颜色的调节在某些应用中是极为重要的.本文首先对共轭高分子荧光颜色调节的两大类机理进行了阐述:直接调节共轭聚合物发光体系的能隙以改变发光颜色,或者将具有不同荧光颜色的材料发出的光叠加获得新的表观颜色.我们还对具体的调节手段进行了初步分类,包括物理共混法、共聚法、改变聚合物主链或侧基结构,以及改变共轭高分子聚集态等方法;在列举具体调节手段同时还引入了共轭高分子体系的实例说明,并对其中调节荧光颜色的可能机理进行了探讨.     

聚磷腈改性及其生物医学应用

聚磷腈是一种具有良好侧基功能化特性的高分子,通过接入不同侧基的聚磷腈与其它聚合物共混共聚,可以制备出具有不同性能的材料。本文介绍了目前关于国内外聚磷腈共混共聚的研究现状,并对聚磷腈改性在生物医学领域的应用及进展作了简要的介绍。     

高分子合金分离膜材料及结构研究进展

膜材料液相共混制备高分子合金分离膜不但可以调节膜材料与被分离物的亲和性，也在一定程度上改变了膜的结构。本文介绍高分子材料浓相共混对膜材料的亲水性、耐污染性及其它理化性能的影响和对膜结构的调节作用，同时指出高分子材料间的相容性是影响合金膜结构的重要因素。     

聚氨酯类反应型高分子表面活性剂的研究进展

反应型高分子表面活性剂兼有反应型表面活性剂可以以牢固的共价键键合到聚合物粒子上,有效避免了表面活性剂在聚合物膜中迁移的优点和高分子表面活性剂性质稳定、耐水性好、低毒或无毒的优点,是一种备受关注的新型表面活性剂,其中含有双键的聚氨酯类可聚合型高分子表面活性剂因其软硬度可调、反应活性高等优点而成为此类研究的一个新热点。本文综述了国内外聚氨酯类反应型高分子表面活性剂最新研究概况,简述了其合成路线和应用性能,并对未来的研究方向进行了预测。     

相形态对聚合物反应共混过程的影响

通过采用典型的热力学不相容共混体系聚烯烃弹性体/聚苯乙烯(POE/PS),利用流变学和形态研究的方法,考察了不同相形态(海岛结构和双连续结构)对聚合物反应共混过程的影响.研究发现相形态对聚合物原位增容共混反应有显著的影响,界面反应的进程与界面形态的变化能力直接相关.对于双连续结构的共混物,其形态稳定性最差,因而最有利于界面反应的发生;而在海岛结构的共混体系中,界面反应的进程则取决于界面变形的难易程度,黏度比小的体系更容易发生界面反应。     

Characteristics and Bond Performance of Wood Adhesive Made from Natural Rubber Latex and Alkaline Pretreatment Lignin

The aim of this study was to characterize an aqueous polymer isocyanate (API) type adhesive made from natural rubber latex (NRL) and lignin as base polymers, and to evaluate bond performance of the adhesive as laminated wood adhesive. The base polymers of the adhesive were prepared by blending NRL, polyvinyl alcohol (PVA), and lignin isolated from black liquor of alkaline pretreatment of oil palm empty fruit bunch (OPEFB) and sugarcane bagasse (SB) with compositions of 25/25/0, 25/20/5, 25/15/10, 25/10/15, 25/5/20, and 25/0/25 (w/w/w). The isocyanate crosslinker was added at the level of 15% of the weight of base polymer. The glass transition temperature (Tg), heat degradation, and the homogenity of the adhesive blend were analyzed. The adhesive was used for producing laminated wood (20×8 cm²). Results showed that the addition of lignin in the base polymer blends of API adhesive did not significantly affect the Tg of the adhesives. However, it affected the thermal decomposition and bond performance of the adhesives. There were more residues and less homogenous adhesive solution due to the addition of lignin in the base polyemr blends of API adhesives. The addition of lignin in the base polymer blends caused significant decrease in bond performance of the adhesive applied in glue laminated wood.     

Preparation and properties of POSS grafted polypropylene by reactive blending

The octavinyl polyhedral oligomeric silsesquioxane (POSS) grafted polypropylene (PP) was first prepared by reactive blending. The structure and properties of physical blending and reactive blending composites of PP/POSS were investigated by wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA). WAXD analysis shows that the POSS in the reactive blending composites has better compatibility with PP than in the physical blending composites. The β-form crystalline hence disappears even the non-reactive POSS can act as an effective β-nucleating agents. DSC analysis shows the reactive blending composites have higher crystalline temperature while POSS in the physical blending composites have little effect on the crystalline temperature. The modulus of reactive blending composites increases in the presence of POSS, while that of the physical blending composites decreases with increasing POSS content.     

An Efficient p–n Heterojunction Photocatalyst Constructed from a Coordination Polymer Nanoplate and a Partically Reduced Graphene Oxide for Visible‐Light Hydrogen Production

A new p–n heterojunction photocatalyst has been synthesized successfully through chemical‐bond‐mediated combination of coordination polymer nanoplates (CPNPs) and partially reduced graphene oxide (PRGO) with a simple colloidal blending process. Photocatalytic H₂ production by the p–n heterojunction photocatalyst PRGO / CPNP was investigated under visible‐light irradiation, which illustrates that PRGO / CPNP exhibits a much higher photocatalytic H₂ production rate than neat the CPNPs. The improvement of this photocatalytic property can be attributed to the inner electrical field formed in the p–n heterojunction, which impedes recombination of photogenerated electrons and holes. In PRGO / CPNP, the existence of the p–n heterojunction has been confirmed by electrochemical methods clearly. For PRGO / CPNP, the reductive degree of the PRGO has a great influence on the H₂ production rate and an ideal condition to get a PRGO / CPNP photocatalyst with higher performance has been obtained.     

聚合物共混：Ⅰ.聚合物共混物的制备方法

本讲主要介绍聚合物共混物的制备方法,其中包括熔融共混、溶液共混、胶乳共混、冷冻干燥共混、接技共聚共混、互穿聚合物网络、就地反应型共混、分子共混等.     

Biodegradation of aliphatic and aromatic polycarbonates

Polycarbonate is one of the most widely used engineering plastics because of its superior physical, chemical, and mechanical properties. Understanding the biodegradation of this polymer is of great importance to answer the increasing problems in waste management of this polymer. Aliphatic polycarbonates are known to biodegrade either through the action of pure enzymes or by bacterial whole cells. Very little information is available that deals with the biodegradation of aromatic polycarbonates. Biodegradation is governed by different factors that include polymer characteristics, type of organism, and nature of pretreatment. The polymer characteristics such as its mobility, tacticity, crystallinity, molecular weight, the type of functional groups and substituents present in its structure, and plasticizers or additives added to the polymer all play an important role in its degradation. The carbonate bond in aliphatic polycarbonates is facile and hence this polymer is easily biodegradable. On the other hand, bisphenol A polycarbonate contains benzene rings and quaternary carbon atoms which form bulky and stiff chains that enhance rigidity. Even though this polycarbonate is amorphous in nature because of considerable free volume, it is non-biodegradable since the carbonate bond is inaccessible to enzymes because of the presence of bulky phenyl groups on either side. In order to facilitate the biodegradation of polymers few pretreatment techniques which include photo-oxidation, gamma-irradiation, or use of chemicals have been tested. Addition of biosurfactants to improve the interaction between the polymer and the microorganisms, and blending with natural or synthetic polymers that degrade easily, can also enhance the biodegradation.     

Novel hybrid systems based on poly(propylene-g-maleic anhydride) and Ti-POSS by direct reactive blending

Novel hybrid systems based on maleic anhydride-grafted polypropylene (PPgMA) and home-made Ti-containing amino polyhedral oligomeric silsesquioxanes (Ti-POSS-NH₂) have been prepared by one-step reactive blending, and their properties have been compared with those of systems based on a non-reactive POSS (POSS). The occurrence of a reaction between PPgMA and the reactive POSS molecules has been assessed by Fourier Transform Infrared Resonance (FTIR) measurements, whereas dispersion of POSS into the polymer was evaluated by Scanning Electron Microscopy (SEM), showing a nanometric dispersion only for the reactive POSS. Thermo-oxidative behaviour was studied by Thermogravimetric Analysis (TGA), showing a delayed volatilization of the PPgMA/Ti-POSS-NH₂ with respect to both PPgMA/POSS and pristine PPgMA, which is attributed to the chemical activity of Ti in Ti-POSS-NH₂. To highlight the mechanism of the hybrid system decomposition, samples which underwent a thermal treatment at 250 °C, i.e. the onset temperature for polymer matrix decomposition in thermo-oxidative conditions, have been studied by FTIR and X-Ray Photoelectron Spectroscopy (XPS) measurements.     

Halogen bonding in polymer science: towards new smart materials

The halogen bond is a special non-covalent interaction, which can represent a powerful tool in supramolecular chemistry. Although the halogen bond offers several advantages compared to the related hydrogen bond, it is currently still underrepresented in polymer science. The structural related hydrogen bonding assumes a leading position in polymer materials containing supramolecular interactions, clearly indicating the high potential of using halogen bonding for the design of polymeric materials. The current developments regarding halogen bonding containing polymers include self-assembly, photo-responsive materials, self-healing materials and others. These aspects are highlighted in the present perspective. Furthermore, a perspective on the future of this rising young research field is provided.

The incorporation of halogen bonding into polymer architectures is a new approach for the design of functional materials. This perspective emphasizes the current development in the field of halogen bonding featuring polymer materials.     

反应性复合乳液的合成、表征及其交联反应

利用种子半连续乳液聚合方法合成了核层或壳层带有环氧基以及壳层带有羧基的3种不同核/壳结构的乳胶粒子,通过物理共混带环氧基和羧基的乳胶粒子,得到了两种反应性复合乳液.利用透射电镜和激光动态光散射对乳胶粒子进行了表征,其粒径分布较窄,粒径分布的多分散系数为0.062,平均粒径约76 nm,乳胶粒子具有明显的核/壳结构.通过胶膜的凝胶率和膨胀率的测定和红外光谱分析对反应性复合乳液中乳胶粒子的扩散及交联反应进行了研究,并探讨了不同核壳结构复合乳液对涂膜机械性能的影响.研究表明,当反应性复合乳液中的环氧基和羧基分别分布在乳胶粒子的核层和壳层时,有利于聚合物分子链的充分扩散和化学交联反应的进行,从而提高涂膜的物理化学性能,当甲基丙烯酸缩水甘油酯(GMA)含量为10 wt%时,涂膜的拉伸强度达20.3 MPa.