支化及超支化聚乙烯研究进展

综述了支化及超支化聚乙烯的制备方法及功能化改性研究进展,重点介绍了后过渡金属催化剂催化乙烯"链行走"制备超支化聚乙烯的研究进展,同时介绍了功能性超支化聚乙烯的应用,并展望了其发展前景。     

聚乙烯蜡的功能化研究进展

概述了近年来国内外对聚乙烯蜡进行功能化研究的成果及应用,并对各种功能化聚乙烯化的方法进行了比较。     

功能化石墨烯改性水性涂料的研究与应用

综述了近年功能化石墨烯改性多种水性涂料的配方组成、制备工艺和涂层主要性能,主要包括功能化石墨烯改性的水性聚氨酯涂料、功能化石墨烯改性的水性环氧涂料、功能化石墨烯改性的水性丙烯酸涂料和功能化石墨烯改性的锌基水性涂料,并对功能化石墨烯改性水性涂料未来的发展趋势进行了阐述和归纳总结.研制开发多功能性绿色环保的石墨烯改性水性涂...     

聚丙烯功能化改性材料研究进展

介绍了聚丙烯功能化改性的研究动向,并对功能化改性聚丙烯进行了简单介绍.     

用汉森溶解度参数评估功能化石墨烯在溶剂中的分散性

石墨烯独特的结构使其容易团聚,不溶于大多数的溶剂,应用受到极大限制。本工作用海藻酸钠(SA)和聚乙烯吡咯烷酮(PVP)表面改性石墨烯抑制石墨烯团聚,用扫描电子显微镜、傅里叶变换红外光谱、拉曼光谱和X射线衍射仪对其进行表征,考察了两种功能化石墨烯在溶剂中的分散性,并根据分散结果计算了汉森溶解度参数。结果表明,石墨烯成功功能化,经两种分散剂表面改性的石墨烯在溶剂中的分散性改变较大,在水中分散性较好,汉森溶解度参数和汉森球半径均发生改变。汉森球半径变大表明表面改性增大了石墨烯在溶剂中的溶解度。     

异戊橡胶功能化改性研究进展

综述共聚合功能化改性、后功能化改性和物理共混引入功能组分这3种方法对异戊橡胶(IR)功能化改性的研究进展,分析不同改性方法的改性机理,并建议加大对IR功能化改性的研究力度,尽快实现功能化IR生产技术的自主化,取代天然橡胶在一些领域的应用。     

聚乙烯中空纤维离子交换膜的制备及应用进展

介绍了聚乙烯中空纤维阴离子交换膜、阳离子交换膜以及两性离子交换膜的制备方法和制备过程.首先采用光束或γ射线照射聚乙烯中空纤维膜表面产生自由基,然后改性单体与自由基反应引入预功能化基团,最后反应试剂与预功能基团进行化学反应制得中空纤维离子交换膜.同时,对制得的中空纤维离子交换膜在蛋白质分离、金属离子去除及酶固定反应方面的...     

功能化聚乙烯蜡／有机蒙脱土插层复合母粒的研制

用两种不同改性剂与蒙脱土进行离子交换制得了两种有机蒙脱土，用功能化聚乙烯与有机蒙脱土进行熔融插层复合制备了功能化聚乙烯蜡/有机蒙脱土插层复合母粒，用X-射线衍射，傅立叶红外光谱，热重分析，差示扫描量热和抽提实验等对所得有机蒙脱土和功能化聚乙烯蜡/有机蒙脱土插层复合母粒的结构与性能进行表征。结果表明，有机蒙脱土层间距的增大和功能化聚乙烯蜡的极性活性官能团使得功能化聚乙烯蜡可以被插入到有机蒙脱土的夹层之间，甚至与层间的有机改性剂形成共价键而不被有机溶剂抽提出来。     

功能化改性橡胶材料在轮胎胶料中的应用

探讨橡胶材料的功能化改性及改性橡胶材料在轮胎胶料中的应用。结果表明:对橡胶功能化改性,可以改善成品轮胎的使用性能和延长使用寿命;对补强填充剂功能化改性,可以提高胶料的物理性能,特别是对白炭黑的表面改性,可以有效解决轮胎胶料的魔三角问题;对硅烷偶联剂功能化改性,可以大大提高胶料的耐热氧老化性能和抗硫化返原性能;功能化改性技术还可以应用于加工助剂。     

功能化改陆像胶材料在轮胎胶料中的应用

探讨橡胶材料的功能化改性及改性橡胶材料在轮胎胶料中的应用。结果表明：对橡胶功能化改性,可以改善成品轮胎的使用性能和延长使用寿命;对补强填充剂功能化改性,可以提高胶料的物理性能,特别是对白炭黑的表面改性,可以有效解决轮胎胶料的“魔三角”问题;对硅烷偶联剂功能化改性,可以大大提高胶料的耐热氧老化性能和抗硫化返原性能;功能化改性技术还可以应用于加工助剂。     

Metallocene‐based functionalized polyolefins as compatibilizers in polyolefin nanocomposites

This article reports a study of some functionalized polyolefins evaluated as compatibilizers in polyethylene nanocomposites. The functionalized polymers were prepared by direct metallocene‐mediated copolymerizations of ethylene and a functional comonomer. The prepared nanocomposites were evaluated for mechanical and barrier property enhancement. A good combination of mechanical and barrier properties was obtained with the metallocene‐based functionalized polyethylene. The toughness–stiffness balance was better than or comparable to that achieved with conventional functionalized polymers such as maleic anhydride grafted polyethylene. The results also indicated that these metallocene‐based functionalized polyolefins, when used as compatibilizers, could have relatively higher molar masses and lower functionality than those of conventional post‐reactor‐modified compatibilizers, and so the drawbacks associated with the latter could be avoided. Their inherent properties could also further improve the final nanocomposite properties. This was attributed to the more homogeneous nature of metallocene‐catalyzed polymers in comparison with post‐reactor‐modified products. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1094–1100, 2004     

Blends of nylon 6 with a polyethylene functionalized by photooxidation

An easy and cheap method to prepare functionalized polyethylene is reported in which polyethylene is photooxidized and then melt-blended with nylon. Structural, rheological, and mechanical modifications indicate that carbonyl, formed during photooxidation, and amine groups react giving rise to copolymers which stabilize the blends. Photooxidized polyethylene from waste could be very effective in preparing polyethylene/polyamide blends with improved properties. This new approach improves over current methods in which compatibilization of polyolefines and polyamides is mostly performed by reacting functionalized polyolefines with polyamides in molten state. The functionalization is achieved by chemical modification of the polyolefines chains. This step could be very expensive.     

Surface of cellulosic materials modified with functionalized polyethylene coupling agents

The interfacial adhesion between a wood fiber and a plastic matrix strongly influences the performance of wood‐fiber‐reinforced thermoplastic composites. Fiber surface modification with coupling agents is generally needed to induce bond formation between the fiber and polymer matrix. This study investigated the chemical reactions between cellulosic materials and functionalized polyethylene coupling agents. Both wood flour and cotton cellulose powder were treated with acrylic acid‐functionalized polyethylene and maleic anhydride‐functionalized polyethylene (maleated polyethylene) for surface modifications, and chemical changes resulting from these treatments were followed by a study of the Fourier transform infrared and X‐ray photoelectron spectroscopy spectra. Variations in the band intensities, oxygen‐to‐carbon ratios, and concentrations of unoxidized carbon atoms were related to changes that occurred on the surfaces of modified cellulosic materials. The experimental results indicated that chemical bonds between the hydroxyl groups of the cellulosic materials and the functional groups of the coupling agents occurred through esterification reactions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 278–286, 2003     

Characterization of grafted polyethylene by contact-angle hysteresis and ESCA studies

Low-density polyethylene (LDPE) has been functionalized in the bulk through dicumyl peroxide (DCP)-initiated grafting of dibutyl maleate (DBM) and vinyltrimethoxysilane (VTMO) in the temperature range from 140 to 200°C. The functionalized surfaces have been characterized through contact angle and contact-angle hysteresis measurements as well as through ESCA studies. The degree of grafting has been determined by infrared spectrophotometry. From the ESCA patterns of the modified polymers, the atomic ratios of oxygen to carbon and silicon to carbon have been calculated. Determination of an empirical relation between contact-angle hysteresis and the oxygen-carbon ratio of the functionalized polymer surfaces has been attempted. It is found that the higher the oxygen-carbon ratio, the lower the contact-angle value for polyethylene. Contact angle-hysteresis increases with increase of the degree of grafting. The total surface energy increases with grafting. The surface energy of the silane-grafted polyethylene (PEgS) is found to be the lower than that of dibutyl maleate-grafted polyethylene (PE_gDBM). © 1993 John Wiley & Sons, Inc.     

Toughening liquid‐crystalline polymers with polyethylenes containing epoxy functionality

To improve toughness, a liquid‐crystalline polymer (LCPs) was blended with polyethylenes containing epoxy functionality in concentrations of 2, 6, and 15 wt %. The blends were prepared with a corotating twin‐screw extruder and were injection‐molded into specimens for mechanical testing. The effect of the amount of the epoxy‐functionalized polyethylenes on the morphology and mechanical and thermal properties was studied. The toughness improved with increasing amount of functionalized polyethylene, and the blend containing 15 wt % epoxy‐functionalized polyethylene had the best toughness properties. Impact strength values up to three times higher than those of the neat LCP were achieved. However, the stiffness of the LCP concurrently decreased substantially. The morphology became much more uniform, and the melting behavior changed. The results show that considerable improvements in the toughness properties of LCPs can be achieved with epoxy‐functionalized polyethylenes. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1886–1891, 2002     

PET/碳纳米管共混物的研究进展

综述了聚对苯二甲酸乙二醇酯(PET)/碳纳米管(CNTs)的共混物的制备和性能。官能化CNTs比未官能化CNTs在PET母体中的分散性得到改善;PET/未官能化CNTs共混物和PET/官能化CNTs共混物相比PET,熔融结晶温度均增高,具有更高的结晶度;PET/未官能化CNTs共混物的熔点变化不大,而PET/官能化CNTs共混物的熔点的变化取决于官能化CNTs中引入官能团的化学结构;PET/未官能化CNTs共混物和PET/官能化CNTs共混物的熔体黏度均比PET有所提高,切力变稀行为比PET也有所增强;PET/未官能化CNTs共混物和PET/官能化CNTs共混物的热稳定性、导电性能及机械性能均得到改善。     

官能化线性低密度聚乙烯的流变行为及力学性能

利用毛细管流变仪研究了官能化ＬＬＤＰＥ（ＬＬＤＰＥ－ｇ－ＡＡ、ＬＬＤＰＥ－ｇ－ＧＭＡ）的流变行为。结果表明：在高的剪切应力下ＬＬＤＰＥ－ｇ－ＡＡ、ＬＬＤＰＥ－ｇ－ＧＭＡ的表观粘度比纯ＬＬＤＰＥ的小。表明官能化ＬＬＤＰＥ的流动性提高了,其加工性能变好。官能化ＬＬＤＰＥ的表观粘度随接枝单体含量的增加而降低,这说明接枝到ＬＬＤＰＥ分子链土的单体起到了内润滑剂的作用。利用Ｉｎｓｔｒｏｎ１１２１拉力机测试了     

聚乙烯亚胺功能化Fe3O4纳米粒子的制备

以油酸包覆的Fe3O4磁性纳米粒子为原料,3,4-二羟苯基丙酸(DHCA)为表面改性剂,四氢呋喃(THF)为溶剂制备出DHCA功能化的Fe3O4纳米粒子。将制备得到的功能化Fe3O4纳米粒子偶联聚乙烯亚胺(PEI),得到稳定分散的聚乙烯亚胺功能化Fe3O4磁性复合纳米粒子。利用FTIR、TEM、VSM、Zeta电位对磁性粒子组分、形貌、粒径、磁学性能和电位性能进行表征。该法简便,反应条件温和,所制备的PEI功能化Fe3O4纳米粒子具有良好的超顺磁性和分散性。     

Mechanical behavior of cold plasma–treated sisal and high‐density polyethylene composites

Sisal fibers and finely powdered high‐density polyethylene were surface functionalized with dichlorosilane on a RF(radio frequency)‐plasma reactor. Composites made from sisal and high‐density polyethylene were compounded using a thermokinetic mixer. The discharged mass was cooled, granulated, and injected molded into composite specimens for testing. The mechanical behaviors (tensile, impact and thermal dynamical mechanical properties) of composites made from cold plasma‐treated and untreated components are compared and discussed. The best mechanical performance was generally obtained for composites where only the inert thermoplastic matrix was plasma‐functionalized. Plasma treatment of lignocellulosic fibers seems to induce decomposition processes of the surface layers structures exposed to the plasma that generally does not contribute to significant improvement on the mechanical behavior of the composite.