复合共挤出技术的现状和发展

共挤出技术是当代广泛应用的先进的高聚物复俣共挤出的理论和实验发展以及复合共挤出的技术和设备的发展进行了回顾,从中可以得到共挤出的发展轨迹,从而我们今后的研究方向及研究方法提供依据。     

反应挤出技术在高聚物本体聚合中的应用进展

反应挤出技术是高聚物加工的一种新技术，是目前国际上竞相投资的热点。在高聚物本体聚合中反应挤出技术具有广阔的发展前景。重点介绍了反应挤出技术的特点，阐述了用反应挤出技术进行本体聚合制备高聚物的优点，综述了国内外近十年来反应挤出技术在高聚物本体聚合中的应用进展。     

多层共挤出薄膜技术的发展概况

多层共挤出薄膜技术是当前广泛应用的1种先进的高聚物复合薄膜加工成型方法,文章对近几十年来高聚物复合薄膜多层共挤出的试验发展以及多层共挤出技术装备的发展进行了回顾.多层共挤出薄膜技术的发展主要体现在复合共挤出机头结构的设计改进.介绍了多层共挤出薄膜技术的发展轨迹,从而为今后的研究和多层复合薄膜的产业化提供依据.     

高聚物的精密挤出

研究了影响高聚物精密挤出的工艺因素和装备因素，提出了高聚物精密挤出的概念，论述了实现高聚物精密挤出的可行性，分析了实现高聚物精密挤出过程的具体措施和手段。     

高聚物精密挤出实验台的研制与应用

研究了影响精密挤出的因素，研制出了精密挤出实验台，用该实验台对LDPE进行了初步挤出实验，并与普通挤出机的实验结果进行了对比。结果表明，该实验台能显著控制高聚物挤出制品的产量波动。     

复合共挤出喂料块三维流动分析

利用美国FLUENT公司研究开发的Polyflow软件，针对带喂料块共挤出机头中共挤出喂料块内的流动进行了分析。首先从理论上分析，创建几何模型，列出控制方程，给出边界条件；然后利用三维有限元方法来求解上述已列出的方程，得出计算结果；最后计算结果分粘度相同和粘度不同的物料复合挤出进行比较分析，得出结论，即多层高聚物熔体的粘度比和流率比会对喂料块内复合挤出流动的界面形状有显著影响。     

二维口模气辅共挤的有限元分析及其对挤出胀大的影响

气辅共挤成型是一种新型的聚合物挤出成型技术。其实质是将气辅挤出技术应用于共挤成型技术,发挥气辅挤出和共挤成型等优点。对气辅共挤进行二维建模,并对其进行有限元分析,结果表明气辅共挤较传统共挤有部分消除挤出胀大的作用。     

高聚物精密挤出的研究

高聚物的挤出成型是一个十分复杂的生产过程[1] 。在此过程中 ,高聚物要经历固体输送、熔融、混合、增压、泵送、成型、冷却固化等过程 ,并受到剪切、拉伸、压缩以及加热、冷却等作用 ,发生熔融、固化、取向、解取向、结晶等复杂的相态和结构变化 ,使得挤出过程的控制难度较大 ,导致制品成型的精度较低。这不仅浪费了大量的树脂材料 ,也限制了高聚物挤出制品的应用范围。为了提高挤出过程的稳定性、均匀性和可靠性 ,科研工作者从挤出过程机理模型、挤出机优化设计、成型工艺条件控制、成型辅机控制等方面做了大量的基础理论研究工作 ,并研制…     

双螺杆反应挤出尼龙-6

双螺杆反应挤出工艺是高分子材料加工的一种新技术，是目前国际上竞相投资的热点。本文将重点介绍作者采用反应挤出新工艺对己内酰胺单体进行双螺杆反应合成高聚物尼龙－６及尼龙－６制品，实现双螺杆挤出机自单体－高聚物－物品的一体化合成工艺过程，突出双螺杆挤出尼龙－６及改性制品固有的特色。     

影响挤出成型精密度的因素

分析了高聚物挤出波动的各种形式,指出中频波动是影响挤出成型的最主要因素;定量研究了影响挤出成型精密度的高聚物材料因素、工艺因素和设备因素,结果表明:压力控制、温度控制、螺杆转速控制以及螺杆结构设计、电机连接方式和高聚物材料种类等是影响挤出成型波动的主要因素。     

纳米技术在高聚物中的应用及其进展

讨论了纳米技术在高聚物中的应用。纳米技术可使高聚物增加韧性、强度和稳定性 ,可以改善高聚物的加工性能、抗老化性能或使材料功能化。但应用中也存在着一些问题 ,例如纳米无机粒子在高聚物中的分散问题及介面粘接问题等 ,对这些问题作了分析并提出相应的解决对策 ,讨论了其研究新进展及工业化进程中需重点关注的问题。     

Recent studies of polymer reactions caused by stress

A singular class of polymer reactions can be caused by mechanical stress. Sufficient storage of mechanical energy to break chemical bonds in the main chain is generally possible only on deformation of polymers of high molecular weight. The corresponding appropriate conditions of high stress may occur in both polymer processing and use. This review summarizes reports of such polymer stress reactions published principally after 1980. The survey is organized by polymer type and by analysis technique.     

纳滤技术在油田调驱配聚中的应用进展

纳滤(Nanofilitration,NF)是一种新型分离技术,对二价离子具有高截留的特性,可分离大部分油田水中的二价离子,如Ca2+、Mg2+、Ba2+、CO32-、SO42-等成垢离子.用纳滤技术处理后的注入水配聚,可减少高价离子对聚合物凝胶的影响.介绍了纳滤处理油田采出水的原理,油田采出水特性,以及纳滤软化注入水...     

A Spectroscopic Technique for Studies of Water Transport Along the Interface and Hydrolytic Stability of Polymer/Substrate Systems

Information on water transport along the polymer/substrate interface is valuable for understanding the mechanisms and the controlling factors affecting the water-induced adhesion loss of polymer-coated metals, adhesive-bonded joints, and polymer/fiber composites subjected to aqueous environments. This paper presents data to demonstrate the capability of a technique, which combines a vertical cell with Fourier transform infrared spectroscopy in the multiple internal reflection mode, for studying water transport along the polymer/substrate interface and interfacial hydrolytic stability of polymeric composites and systems exposed to water and high relative humidities. The technique can distinguish water transport through the film from that along the interface; the latter transport is predominant for polymer/untreated substrate systems. Spectroscopic analyses of fractured surfaces of poor and well-bonded polymer/substrate systems after water exposure indicate that the technique is capable of discerning a hydrolytically-stable interface from a water-susceptible interface.     

Drawing in high pressure CO2—a new route to high performance fibers in memory of late Roger Porter

In this paper, we introduce a new draw technique for polymer orientation and apply it to different polymer fibers: poly(ethylene terephthalate) or PET, nylon 6,6, and ultra‐high molecular polyethylene (UHMWPE). In this technique, a polymer is drawn uniaxially in supercritical CO₂ using a custom high‐pressure apparatus. This technique can be used in replacement of a traditional drawing process or as a post‐treatment process. With PET, the technique is not effective at temperatures at or below 130°. In contrast, the process is highly effective for nylon 6,6 where CO₂ drawn fibers show significantly higher crystallinity and orientation along with improved mechanical properties. While the fibers are plasticized, the drawability of the fibers is only slightly dependent on temperature. High pressure CO₂ drawing of ultrahigh molecular weight polyethylene (UHMWPE) fibers is equally effective. Commercial high performance fibers can be drawn up to a ratio of 1.9 in asecond stage, resulting in large increases in tensile modulus and small improvements in tensile strength.     

Surface pretreatment of glass fiber-reinforced liquid crystalline polymer composites by excimer laser for adhesive bonding

This paper reports the results of using a new laser surface pretreatment technique to improve the strength of adhesive joints. A high power KrF excimer laser at 248 nm output was used to surface-treat a glass fiber-reinforced liquid crystalline polymer (LCP) composite. With optimum process parameters, the polymer matrix at the surface was etched away efficiently and the bare fibers anchored on the matrix were left dangling and undamaged. The surface morphology produced by this new technique resulted in high quality adhesive joints. Both lap-joint and butt-joint configurations were investigated. A 350% improvement in the butt-joint strength was achieved by this new pretreatment technique as compared with that of the untreated one.     

Polymer and Graphite-Derived Nanofiller Composite: An Overview of Functional Applications

In this article, applications of polymer and graphite-derived nanofiller composite have been presented with special emphasis on epoxy composite. Various types of graphitic nanofillers such as graphite, graphene oxide, graphene, and graphene nanoplatelets are reviewed. Recently, polymer/graphite, polymer/graphene oxide, polymer/graphene, and polymer/graphene nanoplatelet-based materials have gained interest due to high performance. Property enhancement is due to high aspect ratio; high surface area; excellent electrical, thermal, and mechanical properties of nanofillers. The filler dispersion depends upon selection of suitable fabrication technique. We also reported on applications of epoxy/graphite-based filler composites in technical fields such as Li-ion batteries, sensors, and solar cells.     

傅立叶变换红外光谱法在高聚物研究中的应用

本文介绍了红外光谱的相关知识、测定原理,以及采用傅立叶变换红外光谱仪对几种高聚物进行结构剖析的实例。结果表明,用红外光谱法可以准确地剖析出高聚物的组成,该方法分析速度快,重现性好,结果令人满意。     

磁性分子印迹聚合物的制备与应用研究

磁性分子印迹聚合物是在磁性微粒表面利用分子印迹技术合成具有超顺磁性、高选择性、高吸附性和特异性识别的聚合物。能在外加磁场作用下实现快速分离和定向移动,是一种新型高分子材料。本文主要介绍了物理法、化学法和模板法3种磁性微粒的制备方法,以及利用分子印迹技术制备磁性分子印迹聚合物,并探讨了悬浮聚合、乳液聚合和沉淀聚合3种聚合方法的研究进展,总结了磁性分子印迹聚合物在农药残留、兽药残留、重金属残留和生物医学方面的应用。分析表明磁性分子印迹聚合物在生物医学领域,尤其是抗菌治疗方面有良好的发展前景。     

Preparation of porous polymer membranes using nano- or micro-pillar arrays as templates

ZnO or polystyrene (PS) pillar arrays were formed on solid substrates and used as templates for the formation of porous polymer membranes. The membranes were formed by casting a polymer solution in the inter-pillar space of these templates and evaporating the solvent. Dissolution of the pillars in a selective solvent resulted in thin films containing monodisperse micrometer-sized channels. Membranes produced using the pillar template technique showed high water permeability and high size selectivity.