单中心催化剂及其聚烯烃材料的研发进展

聚烯烃是一种使用量最大、应用最广,并且生产过程能耗和污染很小的高分子材料,在汽车、包装、建筑、电器、医疗等领域应用十分广泛.随着我国深化供给侧结构性改革,构建国内国际相互促进的新发展格局的推进,解决高端产品自主可控,实现通用产品高质量发展已成为必然趋势.单中心催化剂及其聚合物产品研发,极大丰富了聚烯烃产品种类,拓展了聚...     

聚烯烃技术进展

介绍了聚烯烃技术的最新进展,重点是挂靠在中国石化北京化工研究院的聚烯烃国家工程研究中心在近年来开发的新技术,包括无邻苯二甲酸酯的聚丙烯催化剂等7类新催化剂,非对称加外给电子体等新丙烯聚合工艺,高效抗菌防霉剂等新型复合助剂和含低可溶物的透明聚丙烯树脂等聚烯烃新材料。     

镁基复合材料的制备技术进展

镁基复合材料具有低的密度、优异的力学性能和物理性能,在汽车、航空航天等领域的应用需求日益增加,成为近年来新材料领域的研究热点。介绍了镁基复合材料基体的分类和不同的增强体类型,论述了镁基复合材料的制备方法及应用现状,并对镁基复合材料的发展进行了展望。     

直接法合成三烷氧基硅烷的研究进展

综述了直接法合成三烷氧基硅烷反应机理、所用原料、溶剂、催化剂以及分离纯化工艺.并对其发展前景进行了展望.     

双组分α-二亚胺镍复式催化剂制备长支链聚乙烯

报道以两种后过渡金属催化剂二-(2,6-二甲基苯基)-丁二亚胺氯化镍和二-(2-甲基苯基)-丁二亚胺氯化镍所组成的复式催化体系,催化单一乙烯聚合可制备得到长支链(n≥6)的聚乙烯。在合适的聚合条件下此复式催化剂具有很好的协同作用,其催化活性比任一单一催化剂的催化活性都高。本文详细研究了两种催化荆的摩尔比、聚合温度等聚合条件对催化活性及产物结构的影响。用^13C—NMR、FT—IR、DSC对聚合物进行了表征。     

萘基/菲基双取代喹喔啉单体衍生二炔基-烷氧基苯共聚物的制备及光谱性质

以苯并噻二唑为初始原料,通过硝化、还原、缩合等反应合成了2种新型单体5,10-二溴-2,3,7,8-二萘基双喹喔啉(M1)和5,10-二溴-2,3,7,8-二菲基双喹喔啉(M2)。2种单体分别与1,4-二炔基-2,5-二氧十二烷基苯共聚,得到了2种新型共轭共聚物,聚(2,3,7,8-二萘基双喹喔啉-二炔基-2,5-二氧十二烷基苯)(P1)(产率86.1%)和聚(2,3,7,8-二菲基双喹喔啉-二炔基-2,5-二氧十二烷基苯)(P2)(产率41.6%)。所得单体通过红外光谱、核磁共振等进行了表征。单体和聚合物的紫外-可见吸收光谱中M1的最大吸收波长在339nm,354nm处出现。M2的最大吸收波长分别在304nm,317nm处出现双吸收峰外,在长波431nm,459nm处出现双吸收峰。P1的最大吸收波长在448nm处出现,在305nm和317nm处出现2个吸收峰。P2在短波处吸收峰分别在350nm,368nm处出现。单体荧光光谱图中分别在480nm和579nm出现最大发射峰。聚合物分别在487nm和478nm处出现最大发射峰。得到的共聚物通过X射线衍射发现结晶性较差。     

负载型磁性纳米二亚胺镍催化剂制备新型磁性支化聚乙烯

用纳米Fe3O4磁性粉末作为载体,负载α-二亚胺N i催化剂制得磁性纳米催化剂。通过乙烯在纳米催化剂粒子表面原位聚合得到既不同于结构型磁性材料也不同于普通复合型磁性材料的一种新型磁性支化聚乙烯材料。     

POE与HDPE对PP的协同增韧改性

以两种高密度聚乙烯(HDPE)和三种聚烯烃弹性体(POE)为增韧剂,对聚丙烯(PP)进行共混改性,探讨增韧剂结构和含量对PP韧性和流动性能的影响规律,获得了最佳混合比。实验发现:POE和HDPE有增韧效果,POE的效果优于HDPE;但降低其熔体质量流动速率(MFR)。当POE:HDPE:PP为25:15:60时,三元复合体系的简支梁缺口冲击强度为74.21KJ·m~(-2),较纯PP提高了13倍。     

用复合材料制造炼镁还原罐的技术进展

简述了炼镁还原罐制造技术的概况，提出了以低镍耐热钢为基体，高温喷涂陶瓷类材料涂层的还原罐制造方案，指出用复合材料制造还原罐的技术研究是提高还原罐使用寿命的努力方向。     

镁基储氢合金制备技术的研究进展

镁基储氢合金以其储氢容量高、质量轻、资源丰富等一系列优点,成为目前很有发展前景的储氢合金材料之一。综述了镁基储氢合金制备工艺的研究进展,对高温熔炼法、机械合金化法、扩散法和电沉积法这4种镁基储氢合金的制备方法进行了概述,并对镁基储氢合金性能的改善方法进行了简略总结。通过对比各制备方法之间的区别及特点,对镁基储氢合金制备方法的发展方向进行了分析与展望。     

Research on super-hydrophobic surface of biodegradable magnesium alloys used for vascular stents

Micro-nanometer scale structure of nubby clusters overlay was constructed on the surface of an AZ31 magnesium alloy by a wet chemical method. The super-hydrophobicity was achieved with a water contact angle of 142° and a sliding angle of about 5°. The microstructure and composition of the super-hydrophobic surface were characterized by SEM and FTIR. Potentiodynamic polarization and electrochemical impedance spectroscopy were used to evaluate the corrosion behavior, and the hemocompatibility of the super-hydrophobic surface was investigated by means of hemolytic and platelet adhesion tests. Results showed that the super-hydrophobic treatment could improve the corrosion resistance of magnesium alloys in PBS and inhibit blood platelet adhesion on the surface, which implied excellent hemocompatibility with controlled degradation.     

Structural studies of active carbon used in the growth of silicon carbide catalyst support

The microstructure of active carbon used in the growth of a silicon carbide catalyst support has been studied by BET area measurements, electron diffraction and high-resolution electron microscopy. The microstructure of the active carbon is consistent with different distributions of basic structural units (BSUs). These BSUs increase in size under heat treatment by forming adjacent distorted columns. Ordering processes are discussed from geometrical considerations based on reciprocal patterns. The reactivity of the interface between the active carbon and SiO vapour is controlled by the proportion of the highly reactive sites in the active carbon surface structure.     

Research status and development of magnesium matrix composites

ABSTRACT

Magnesium and its alloys, as the metal materials with the lowest density among structural materials, have attracted much attention due to their excellent properties such as high specific stiffness, good electromagnetic shielding properties and good vibration damping effects. However, its low strength, inherent brittleness and poor corrosion resistance limit its application in various industries. By adding a reinforcing phase to the magnesium matrix, a magnesium-based composite material having excellent properties has become one of the effective ways to realise the industrial application of magnesium alloys. This article reviews the recent research progress of magnesium-based composites, including the reinforcing phases and preparation methods of magnesium-based composites, and looks forward to the future development and research directions of magnesium-based composites.     

A study of various characteristics of supported NiO/bentonite catalyst used in the polymerization of methyl methacrylate

Several samples of a supported NiO/bentonite catalyst were studied after pretreatment at either 300 or 500° C. The TGA results revealed that at 300° C, a fraction of nickel nitrite remains stabilized by the bentonite matrix. This fraction reaches its maximum level in samples IVa and Va (or 15 and 20% NiO w/w, respectively). From a study of the surface characteristics, it could be concluded that the nitrite fraction is located in the narrower pores of the catalyst system. The activity tested in the polymerization of MMA indicated that samples IVa and Va are the most active ones. The importance of the surface factor as well as the degree of fractional surface coverage by Ni²⁺ ions, or equivalently by the corresponding anions, could be tested. The results showed that the polymerization process proceeds via an anionic mechanism as enhanced by the presence of NO ₂ ^– ions; the effect becoming much more pronounced in samples IVa and Va. The high stereospecific nature of the produced polymer in all cases can be attributed to the bentonite support effect, being activated by dispersing nickel oxide or other nickel species in its layer structure at both temperatures studied.     

非均相聚合工艺制备高分子量聚丙烯腈的研究进展

综述了非均相聚合工艺制备高分子量聚丙烯腈(PAN)聚合物的工艺特点及研究现状。由此可见,采用非均相聚合体系有利于制备高分子量的PAN聚合物,并成为制备高性能PAN基碳纤维的优良前驱体。     

压铸镁合金焊接气孔问题研究现状及发展

综述了近年来国内外针对压铸镁合金焊接气孔问题的研究现状及发展趋势,主要包括压铸镁合金焊接气孔的气体来源、形成机制、影响因素及防治措施4个方面。通过综合分析,认为母材中高的原始含气量是影响压铸镁合金焊接气孔倾向的主要因素。由于压铸镁合金原始含气量高,传统的防治焊接气孔产生的措施起到的作用都十分有限,采用冶金措施可能是解决压铸镁合金焊接气孔问题的有效方法。     

复合引发剂在水相沉淀法制备聚丙烯腈中的应用

采用不含碱金属离子的氧化还原复合引发体系,以丙烯腈为第一单体,衣康酸为共聚单体,使用水相沉淀聚合法制备碳纤维用聚丙烯腈.研究了不同复合引发剂,单体配比,聚合反应温度和引发剂氧还比的改变对共聚反应的影响.结果表明,在不影响转化率的同时,以过硫酸按和亚硫酸按组成的复合引发体系反应温度比单引发剂至少降低了 1/3,得到的聚合...     

介孔炭作为加氢脱硫催化剂载体材料的研究

以介孔硅SBA-15为模板,焦糖和呋喃醇为碳源,通过多种浇注法制备介孔炭材料.采用低温氮吸附、透射电镜和X射线小角衍射分析模板及介孔炭的织构.结果显示合成的介孔炭成功地复制了SBA-15的结构.以制备的介孔炭作载体担载钴钼合成了加氢脱硫催化剂,利用X射线能谱、透射电镜能量分布谱及一氧化氮化学吸附评估了催化剂的活性及活性点分布,结果表明介孔炭担载的催化剂活性高于活性炭担载的同类催化剂.