聚甲醛自润滑复合材料的开发与应用

综述了通过向聚甲醛树脂中添加耐磨聚合物、润滑油及润滑脂，无机润滑剂，纤维材料，金属粉末或薄片，复合润滑剂，以及嵌段共聚，与金属复合改性的方法来制备聚甲醛润滑复合材料，介绍了8类聚甲醛自润滑复合材料的主要性能和应用领域，对聚甲醛自润滑复合材料发展方向及国内聚甲醛复合改性的现状和前景进行了展望。     

聚甲醛树脂的发展和今后的课题

聚甲醛的生产始于1960年,美国杜邦公司最先以牌号为“Delrin”的均聚物出售。1962年,赛拉尼斯公司开始生产共聚甲醛,并以“Celcon”商标出售。日本1962年就由上述两家美国公司进口聚甲醛产品,日本用自己技术生产聚甲醛始于1972年。一、需要动向 1970年日本国内对聚甲醛的需要量为1.1万吨,1980年达到了4.3万吨,十年间消费量增长了2.8倍,平均年增长率为14％。1981年日本生产量为4.8万吨(出口量包括在内)。在美国,1970年的消费量虽已达2.8     

聚甲醛及其改性产品在汽车工业中的应用前景

介绍了聚甲醛及其改性产品的特性和在汽车工业中的应用领域,总结了汽车工业对聚甲醛产品的要求和聚甲醛改性研究方向,阐述了聚甲醛及其改性产品在汽车工业中的应用前景,展望了汽车工业用聚甲醛产品的研发中应注重的方向.     

浅谈工程塑料聚甲醛的发展和应用

介绍国内外聚甲醛的生产发展历史,并总结聚甲醛市场应用状况,同时对聚甲醛行业的发展提出建议和展望。     

聚合反应对共聚甲醛不稳定末端基的影响研究

研究了聚甲醛生产过程中的反应温度、引发剂三氟化硼用量、反应物配合比、反应物二氧五环添加方式及聚合方式等对聚甲醛不稳定末端基(HO)的影响,研究结果表明,在反应温度为89℃,引发剂用量为50×10~(-6),采用引发剂与二氧五环单体先期聚合条件下,不稳定末端基含量最低,为0.86%,此时聚甲醛的热稳定性最好,初始热分解温度为314℃,二氧五环的加入,能够有效地提高聚甲醛分子链的热稳定性,减少不稳定末端基,聚甲醛不稳定末端基对聚甲醛的热分解温度具有较大影响,随着不稳定末端基的升高,聚甲醛的热分解温度随之降低,热稳定性下降;经过对反应条件研究优化后,聚甲醛的热分解温度比原先提高了25℃。     

化工新型材料

沈阳化工学院开发成功新型晶须增强环氧复合材料；万吨级二氧化碳泡沫塑料项目正式商业化投产；10万吨生物降解塑料项目落户桂林；河北石家庄将建15万吨生物降解塑料项目；新疆布局国内最大聚甲醛项目。     

旭化成APZ共聚甲醛基础认知及开发推广

正1聚甲醛认知及APZ的简介聚甲醛(polyformaldehyde)热塑性结晶聚合物,被誉为"超钢",又称聚氧亚甲基,简称POM。聚甲醛是一种表面光滑,有光泽的硬而致密的材料,淡黄或白色,其耐磨性和自润滑性也比绝大多数工程塑料优越,又有良好的耐油、耐过氧化物性能。聚甲醛的拉伸强度达70MPa,吸水性小,尺寸稳定,有光泽,这些性能都比尼龙好。聚甲醛为高度结晶的树脂,在热塑性树脂中是最坚韧的。具抗热强度,弯曲强度,耐疲劳性强度均高,耐磨性和电性能优良。旭化成聚甲醛(张家港)有限公司(简称"APZ")生产的聚甲醛树脂可被广泛应用于齿轮、凸轮、滚轮以及用于汽车部件     

宝理推出高机械性能共聚甲醛

日本宝理塑料(Polyplastics)公司最近向市场推出高机械性能聚甲醛共聚物Duracon HP-X系列新产品。 新牌号开发基于该公司的聚合技术和控制分子结晶技术。该技术使聚甲醛共聚物与聚甲醛均聚物结晶度相近,因而使产     

计算机辅助TG法研究聚甲醛热降解

本文借助于电子计算机,用动态热重分析(TG)力学。得出了聚甲醛在空气和氮气中热降解反应级数、同温度下的使用寿命。法研究了聚甲醛(POM)热降解反应的动活化能和频率因子,并估算了聚甲醛在不     

碳纳米管/聚甲醛复合材料的结晶形态与力学性能

在对碳纳米管(CNT)进行表面修饰后,采用活性自由基聚合法(ATRP)在其表面接枝聚甲基丙烯酸甲酯(PMMA)。再将接枝上聚合物的碳纳米管添加到聚甲醛中熔融共混制得碳纳米管/聚甲醛纳米复合材料。通过偏光显微镜观察其结晶形态,并研究了功能化碳纳米管的含量对聚甲醛缺口冲击强度的影响,结果表明,CNT-PMMA的加入使聚甲醛球晶细化,复合材料的缺口冲击强度得到提高。     

Strength, Durability, and Safety of Engineering Systems

The evolution of approaches to the solution of machine dynamics and strength problems on the basis of determining static and dynamic nominal and local stresses of the operating load is discussed. It is shown how the material strength and plasticity characteristics, the cyclic strength characteristics in the high-cycle and low-cycle fatigue regions, the high-temperature long-term strength and creep characteristics, and the linear and nonlinear characteristics of fracture mechanics were sequentially used as the basic criterial parameters of the deformability and strength of structural materials. Particular emphasis was given to the results of studies on machine safety and catastrophe mechanics. Integrated approaches to the solution of strength and safety problems of potentially dangerous facilities (nuclear power stations, spacecraft complexes, aircraft, chemical plants, etc.) by analysis of all stages of their life cycle, including design, manufacture, testing, and operation, are discussed.     

Biomaterials and Advanced Technologies for Hemostatic Management of Bleeding

Bleeding complications arising from trauma, surgery, and as congenital, disease‐associated, or drug‐induced blood disorders can cause significant morbidities and mortalities in civilian and military populations. Therefore, stoppage of bleeding (hemostasis) is of paramount clinical significance in prophylactic, surgical, and emergency scenarios. For externally accessible injuries, a variety of natural and synthetic biomaterials have undergone robust research, leading to hemostatic technologies including glues, bandages, tamponades, tourniquets, dressings, and procoagulant powders. In contrast, treatment of internal noncompressible hemorrhage still heavily depends on transfusion of whole blood or blood's hemostatic components (platelets, fibrinogen, and coagulation factors). Transfusion of platelets poses significant challenges of limited availability, high cost, contamination risks, short shelf‐life, low portability, performance variability, and immunological side effects, while use of fibrinogen or coagulation factors provides only partial mechanisms for hemostasis. With such considerations, significant interdisciplinary research endeavors have been focused on developing materials and technologies that can be manufactured conveniently, sterilized to minimize contamination and enhance shelf‐life, and administered intravenously to mimic, leverage, and amplify physiological hemostatic mechanisms. Here, a comprehensive review regarding the various topical, intracavitary, and intravenous hemostatic technologies in terms of materials, mechanisms, and state‐of‐art is provided, and challenges and opportunities to help advancement of the field are discussed.     

再论标准和标准化的基本概念

本文是作者再次对标准和标准化的概念进行讨论。首先讨论的是标准化的目的、主体和对象。作者认为标准化的目的是控制、有序化和统一化;标准化的主体是人/机构;标准化对象可以是具体的或抽象的事物,也可以是它们的组合;任何事物都可以抽象地表达为实体(entity)。第二,作者讨论了标准和标准化的本质以及它们的作用;认为从内容角度看,标准是匹配问题解决方案,也是为标准化对象规定需要满足的要求;从实施角度看,标准是规则;标准化则是制定、实施、传播标准的过程;标准的作用是能够创建并组织现实世界,并能够为相关方建立互相交流和共同理解的基础;标准化的作用是对创新方案进行选择和简化,阻止现实世界过度无序化发展,形成复杂化和简化之间的平衡。第三,作者讨论了标准的记录形式、自愿/强制属性和时空范围,认为标准的记录形式有文件、样品、图形符号、物理表达等多种形式;标准具有选择的自愿性和实施的强制性;标准在时空范围内是有限的。文章的结尾给出了理解标准化概念的框架。     

贮藏温度对采后上海青叶片衰老及活性成分的影响

目的为了探究不同贮藏温度对采后上海青叶片衰老及活性成分的影响。方法以上海青为实验材料,分别在0,5,10,15,20,25,30℃下贮藏,对上海青叶片的感官品质、色差、叶绿素含量、丙二醛(MDA)含量、类胡萝卜素含量、叶黄素含量、叶酸含量和亚硝酸盐含量的变化进行分析。结果与20,25,30℃相比,在10℃和15℃下贮藏可减缓上海青叶片L^*值、b^*值、MDA含量和亚硝酸盐含量的增加,以及|a^*|值、叶绿素含量、类胡萝卜素含量、叶黄素含量和叶酸含量的降低;与10℃和15℃贮藏条件相比,在0℃和5℃下贮藏可显著抑制上海青叶片L^*值、b^*值、MDA含量和亚硝酸盐含量的增加,以及|a^*|值、叶绿素含量、类胡萝卜素含量、叶黄素含量和叶酸含量的降低,减缓上海青叶片的黄化衰老进程,从而维持上海青良好的外观品质。在贮藏温度为20,25,30℃时,上海青的最大贮藏期不超过4 d;贮藏温度为10℃和15℃时,最大贮藏期分别不超过9 d和7 d;贮藏温度为0℃和5℃时,最大贮藏期分别不超过40 d和15 d。结论在低温条件下贮藏,尤其是在0℃下贮藏可最大限度地减缓采后上海青叶片的衰老进程,可维持其较高的活性成分,并抑制其组织中亚硝酸盐的积累,显著延长上海青的贮藏期。     

Clay‐Inspired MXene‐Based Electrochemical Devices and Photo‐Electrocatalyst: State‐of‐the‐Art Progresses and Challenges

MXene, an important and increasingly popular category of postgraphene 2D nanomaterials, has been rigorously investigated since early 2011 because of advantages including flexible tunability in element composition, hydrophobicity, metallic nature, unique in‐plane anisotropic structure, high charge‐carrier mobility, tunable band gap, and favorable optical and mechanical properties. To fully exploit these potentials and further expand beyond the existing boundaries, novel functional nanostructures spanning monolayer, multilayer, nanoparticles, and composites have been developed by means of intercalation, delamination, functionalization, hybridization, among others. Undeniably, the cutting‐edge developments and applications of clay‐inspired 2D MXene platform as electrochemical electrode or photo‐electrocatalyst have conferred superior performance and have made significant impact in the field of energy and advanced catalysis. This review provides an overview of the fundamental properties and synthesis routes of pure MXene, functionalized MXene and their hybrids, highlights the state‐of‐the‐art progresses of MXene‐based applications with respect to supercapacitors, batteries, electrocatalysis and photocatalysis, and presents the challenges and prospects in the burgeoning field.     

Thermophysical properties of some key solids: An update

In 1985, the CODATA Bulletin published a Report of its Task Group on Thermophysical Properties of Solids which analyzed available data on, and gave recommended values for, the heat capacity of Cu, Fe, W, and Al₂O₃, the thermal expansion of Cu, Si, W, and Al₂O₃, the electrical resistivity of Cu, Fe, Pt, and W, the thermal conductivity of Al, Cu, Fe, and W, and the absolute thermopower of Pb, Cu, Pt, and W. The analysts for the different properties were R. B. Castanet, S. J. Collocott, P. D. Desai, C. Y. Ho, J. G. Hust, R. B. Roberts, C. A. Swenson, and G. K. White. The present paper is an updated version of the earlier report and includes more recent data which change some of the recommended values. notably the heat capacity of Cu and W and the thermal expansion of Si and W.     

焦磷酸盐镀铜生产工艺(Ⅰ)

对焦磷酸盐镀铜的前处理、预镀、焦磷酸盐镀铜的工艺配方、操作条件及原理、镀液的配制、镀液成分及其作用、操作条件对镀层的影响、镀液的维护、杂质的影响及其排除方法、镀液成分失调的影响与纠正、磷酸根对镀液和镀层的影响、铜粉的产生及其排除、常见故障及其排除方法等都作了详细阐述.此外,对镀铜液中磷酸根和焦磷酸根的分析方法以及不合格铜层的退除也作了一定的介绍.     

江澳两地高校文创设计的协同研究与商业实践

目的 探索江门世遗文化的传承、发展和转化的新思路,践行国家在《粤港澳大湾区发展规划》纲要中要求江门承担与港澳地区文化创意合作与开发任务的分工。方法 与澳门高校紧密合作,开展专业培训课程,以开平碉楼为例,从人文视角开展设计研究,梳理开平碉楼的文化脉络,把世遗文化的元素和其背后的文化融入文创产品中,提升文创产品的附加值,推动当地文创产业结构的变革。结果 两地高校构建了稳定的科研团队,开设长期有效的设计培训课程,与景区建立了研究协作关系,帮助景区构建了一套产销研的商业模式。结论 以跨区域高校合作为平台,以文创产品为抓手,依托江澳两地的资源优势,可以构建江门世遗文化全新的品牌形象,最终推动开平世遗文化的活化。     

亚稳态球霰石相碳酸钙的调控制备进展

球霰石以其独特的机械、物理和化学性能, 在日用品与生物医学等领域表现出广阔的应用前景。然而在三种无水碳酸钙晶体中, 球霰石的热力学性能最不稳定, 在后续的反应和处理过程中常常转变为更稳定的文石或方解石, 因此如何抑制球霰石向稳定晶型转变一直都是碳酸钙领域研究的热点。本文在概述了球霰石晶体结构、性质、应用及其转化途径的基础上, 以碳酸钙的三种基本制备体系为线索, 综述了碳化法、复分解法、微乳液法和溶剂热法等传统方法以及自组装单分子膜法、仿生合成法和热分解法等一些新型调控制备球霰石相方法的研究进展, 还就利用添加剂促进球霰石形成与稳定的相关机制加以剖析。文章旨在为球霰石相碳酸钙的有效制备提供理论和实践的参考。     

Hollow‐Structured Mesoporous Materials: Chemical Synthesis,Functionalization and Applications

Hollow‐structured mesoporous materials (HMMs), as a kind of mesoporous material with unique morphology, have been of great interest in the past decade because of the subtle combination of the hollow architecture with the mesoporous nanostructure. Benefitting from the merits of low density, large void space, large specific surface area, and, especially, the good biocompatibility, HMMs present promising application prospects in various fields, such as adsorption and storage, confined catalysis when catalytically active species are incorporated in the core and/or shell, controlled drug release, targeted drug delivery, and simultaneous diagnosis and therapy of cancers when the surface and/or core of the HMMs are functionalized with functional ligands and/or nanoparticles, and so on. In this review, recent progress in the design, synthesis, functionalization, and applications of hollow mesoporous materials are discussed. Two main synthetic strategies, soft‐templating and hard‐templating routes, are broadly sorted and described in detail. Progress in the main application aspects of HMMs, such as adsorption and storage, catalysis, and biomedicine, are also discussed in detail in this article, in terms of the unique features of the combined large void space in the core and the mesoporous network in the shell. Functionalization of the core and pore/outer surfaces with functional organic groups and/or nanoparticles, and their performance, are summarized in this article. Finally, an outlook of their prospects and challenges in terms of their controlled synthesis and scaled application is presented.