连续反应挤出高粘度PA6 (Ⅰ)反应挤出PA6工艺及技术特性

系列论述作者运用反应挤出技术由单体己内酰胺直接制备高聚物ＰＡ６及其制品的工艺过程。介绍并分析以自行设计改制的双螺杆挤出机为反应器，来同时完成化学反应和加工成型二大过程的反应性挤出工艺生产流程，提出了ＰＡ６生产的新的合成工艺，以及由该工艺制备的反应挤出ＰＡ６（ＲＥＸＰＡ６）及其制品的性能特点。本工作将分以下部分连续刊载：１反应挤出ＰＡ６工艺及技术特性；２双螺杆挤出机反应合成ＰＡ６；３反应挤出ＰＡ６的树脂改性及制品。     

AAS/PA-6合金的相容性

用反应挤出法制备了一系列的尼龙６／苯乙烯丙烯酸丁酯丙烯腈共聚物（ＰＡ６／ＡＡＳ）合金的相容剂,采用透射电子显微镜（ＴＥＭ）观察了所得合金的微观形态,结合合金的力学性能,对所选用及所制备相容剂进行了筛选。结果表明,以ＳＥＢＳ与ＭＡＨ的接枝物作为相容剂（ＳＥＢＳ是苯乙烯,丁二烯的三嵌段共聚物）,或以ＳＥＢＳ的ＭＡＨ接枝物与ＳＭＡ（苯乙烯马来酸酐聚合物）作为复合相容剂,既可得到以粘度较高的ＡＡＳ为连续相且冲击强度很高的ＡＡＳ／ＰＡ６合金,也可以得到以ＰＡ６为连续相高冲击强度的ＰＡ６／ＡＡＳ合金。     

旋转/牵引速度比对旋转挤出聚乙烯管结构和性能的影响

采用自行研制的聚合物管旋转挤出装置,研究了旋转挤出过程中旋转/牵引速度比对聚乙烯(PE)管结构和性能的影响。扫描电镜(SEM)和热收缩实验结果表明,通过控制旋转/牵引速度比,可有效调节PE管内串晶偏离轴向的角度,降低轴向取向度,提高PE管的力学性能。当旋转/牵引速度比为0.6时,旋转挤出PE管的环向拉伸强度从常规挤出管的19.4MPa提高到33.5MPa,提高了72.7%。     

PP/PA6原位成纤复合材料 I.形态与力学性能

不相容的通用热塑性塑料聚丙烯（ＰＰ）和尼龙６（ＰＡ６）共熔挤出，当ＰＡ６为分散相时，得到了ＰＡ６纤维分散于ＰＰ基体中的原位复合材料。在ＰＰ和ＰＡ６的熔点之间成型，可以保持住纤维的形态。材料的拉伸强度下降，但冲击强度得到大幅度提高。     

HDPE/尼龙-6/EAA共混体系反应增容作用的研究EI

通过Ｂｒａｂｅｎｄｅｒ、ＤＳＣ、ＳＥＭ和力学性能测试研究了在ＨＤＰＥ／尼龙－６共混过程中ＥＡＡ对体系的增容作用、力学性能以及结晶行为的影响。研究结果表明，在反应共混过程中，ＥＡＡ中丙烯酸链段与尼龙－６末端胺基发生了化学反应，就地形成的ＥＡＡ－尼龙－６接枝共聚物对ＨＤＰＥ／尼龙－６体系有增容作用，因而明显减小了相区尺寸，提高了拉伸强度。由于在共混过程中有接枝共聚物形成，明显降低了尼龙－６的结晶。     

PET与液晶高分子注射模塑原位复合材料的研究

ＰＥＴ与液晶高分子（ＬＣＰ）ＶｅｃｔｒａＡ－９５０共混使ＰＥＴ常温模具注射模塑制品结晶完善，并形成原位复合材料。ＰＥＴ与ＬＣＰ挤出共混，注射模塑制得试样。用ＤＳＣ、ＳＥＭ、流变仪、力学性能测试仪等手段，表征共混体系的热行为、结构形态、流变性能和力学性能。结果表明，共混体系中ＰＥＴ结晶行为有趋完善的变化；在２９０共混物熔体表观粘度均小于两纯组分ＰＥＴ和ＬＣＰ的表观粘度；ＬＣＰ在试样中形成微纤，试样拉     

PP/ PA6原位成纤复合材料II. 加工条件对性能、形态的影响

在PP/ PA 6共混物的挤出加工中分别调整加工温度、挤出机螺杆转速、牵引速率, 得到不同加工条件下的PP/ PA 6原位成纤复合材料。研究了加工条件与分散相形态、力学性能的关系。发现当螺杆转速越高、牵引速率越快、加工温度越低, 分散的PA 6纤维尺寸越小, 复合材料的力学性能越好。     

成型加工工艺对紫外线辐照HDPE／PA6共混材料形态结构和对有 …

采用ＳＥＭ和对甲苯渗透性的测试研究了紫外线辐照高密度聚乙烯／尼龙６（ＨＤＰＥ／ＰＡ６）共混物的成型工艺，形态结构以及有机溶剂的阻隔性能，结果表明，在接近ＰＡ６熔融温度时通过挤出成型的试样，其中ＰＡ６为不连续相，层状分布在ＨＤＰＥ基体中，对甲苯有较好的阻隔性能，当成型温度高于和低于ＰＡ６的熔融温度时，成型样品中ＰＡ６呈粒状，对甲苯基本不具有阻隔性能。     

成型加工工艺对紫外线辐照HDPE/PA6共混材料形态结构和对有机溶剂阻隔性能影响的研究

采用ＳＥＭ和对甲苯渗透性的测试研究了紫外线辐照高密度聚乙烯／尼龙６（ＨＤＰＥ／ＰＡ６）共混物的成型工艺、形态结构以及对有机溶剂的阻隔性能。结果表明，在接近ＰＡ６熔融温度时通过挤出成型的试样，其中ＰＡ６为不连续相，层状分布在ＨＤＰＥ基体中，对甲苯有较好阻隔性能；当成型温度高于和低于ＰＡ６的熔融温度时，成型样品中ＰＡ６呈粒状，对甲苯基本不具有阻隔性能。     

增容剂对尼龙6／乙烯~＝醋酸乙烯酯共聚物共混合金的亚微形态与力学性能的影响

采用两种含有羧基官能团的共聚物作为增容剂，通过反应挤出法制备了尼龙６／乙烯－醋酸乙烯酯共聚物（ＥＶＡ）共混合金；并对合金的力学性能和亚微形态进行了研究．结果表明，通过挤出过程中增容剂的羧基官能团与尼龙６反应，可提高尼龙６与ＥＶＡ的界面粘结性，从而使合金获得较高的缺口冲击强度，同时合金的断裂伸长率也显著提高ＳＥＭ研究显示，ＥＶＡ与尼龙６的相容性较差，基体中ＥＶＡ粒子直径约为１．５——２．０μｍ；而添加增容剂后，可以提高ＥＶＡ在基体中的分散性，并使分散相粒子的直径显著减小     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from