N-苯基马来酰亚胺/苯乙烯/α-甲基苯乙烯/马来酸酐四元共聚物的制备及对ABS的改性

以过氧化苯甲酰为引发剂,采用溶液聚合的方法合成了N-苯基马来酰亚胺/苯乙烯/α-甲基苯乙烯/马来酸酐四元共聚物。保持马来酸酐单体质量分数为5%,N-苯基马来酰亚胺单体质量分数为30%,改变α-甲基苯乙烯和苯乙烯的投料比合成系列四元共聚物。采用红外光谱、核磁共振和凝胶渗透色谱对四元共聚物的化学结构和相对分子质量进行了表征,考察了四元共聚物对ABS树脂耐热性及力学性能的影响。结果表明,α-甲基苯乙烯和苯乙烯的投料比为1∶1,数均相对分子质量为2.50×10~4左右的四元共聚物的玻璃化转变温度(T_g)最高达到253.3℃,5%热分解温度可达到351℃。该共聚物可使ABS共混物T_g升高到124.7℃,且具有较好的力学性能。     

N-(苯并环丁烯-4-基)马来酰亚胺的制备及热稳定性

对N-(苯并环丁烯-4-基)马来酰亚胺原有文献的合成方法进行了改进,在温和条件下使该单体产率有所提高。研究了该单体分别与苯乙烯和N-苯基马来酰亚胺在溶液中的二元共聚反应,对所得的共聚物进行表征,并对其热性能进行了分析。结果表明,N-(苯并环丁烯-4-基)马来酰亚胺的均聚物具有很高的热分解温度,初始分解温度为400℃,480℃的热失重仅为10%,将其与苯乙烯共聚可显著提高苯乙烯的耐热性,有望用于高性能复合材料的树脂基体。     

马来酰亚胺-丙烯酸酯共聚物的制备及在热纳米压印抗蚀剂的应用EI

马来酰亚胺与丙烯酸酯通过自由基溶液聚合制备了马来酰亚胺-丙烯酸酯共聚物(P(AA-MI-AHA))。根据凝胶渗透色谱,共聚物的多分散系数低于2,表现出窄的分子量分布特点;根据热失重分析和差示扫描量热分析,聚合物热分解温度高于140℃,玻璃化温度约为128℃,展现出较好的热稳定性。将共聚物用作热纳米压印抗蚀剂材料,研究了共聚物的微纳米图案复制能力。扫描电子显微镜观察到排列规整的条纹图案,分辨率约为100 nm。综上表明,所得马来酰亚胺-丙烯酸酯共聚物用作热纳米压印抗蚀剂材料展现出较好的图像复制能力。     

马来酰亚胺-丙烯酸酯共聚物的制备及在热纳米压印抗蚀剂的应用

马来酰亚胺与丙烯酸酯通过自由基溶液聚合制备了马来酰亚胺-丙烯酸酯共聚物（P(AA-MI-AHA)）。根据凝胶渗透色谱，共聚物的多分散系数低于2，表现出窄的分子量分布特点；根据热失重分析和差示扫描量热分析，聚合物热分解温度高于140℃，玻璃化温度约为128℃，展现出较好的热稳定性。将共聚物用作热纳米压印抗蚀剂材料，研究了共聚物的微纳米图案复制能力。扫描电子显微镜观察到排列规整的条纹图案，分辨率约为100 nm。综上表明，所得马来酰亚胺-丙烯酸酯共聚物用作热纳米压印抗蚀剂材料展现出较好的图像复制能力。     

高性能含硅、氟甲基丙烯酸酯共聚物的研究

制备了γ-甲基丙烯酰氧基丙基三(三甲基硅基)硅烷W D、γ-甲基丙烯酰氧基丙基三乙氧基硅烷及其与甲基丙烯酸异冰片酯、甲基丙烯酸异丁酯和含氟甲基丙烯酸酯的共聚物,通过IR、水接触角、吸水率、铅笔硬度和DSC等手段研究了共聚工艺、含氟单体、硅烷单体及催化交联剂对共聚物膜表面性能和力学性能的影响。延迟滴加有机硅单体尤其是W D和含氟单体可使低用量硅氟单体下的共聚物膜表面憎水性大大增强;催化交联剂可使共聚物的玻璃化温度从31.21℃提高到53.12℃,膜的铅笔硬度达到4H以上。     

不同聚合方法对耐热有机玻璃结构与性能的影响

以甲基丙烯酸甲酯，苯乙烯和Ｎ－环己基马来酰亚胺为主要原料，分别运用溶液法和悬浮法共聚合成耐热有机玻璃，通过选取四个典型配比，比较了两种聚合方法对共聚物中残留Ｎ－环己基马来酰亚胺的浓度，共聚物的分子量，分子量分布及其耐热性的影响。     

耐热级ABS树脂的研制

研究了不同耐热剂对ABS耐热性作用效果的差异,实验表明：N-苯基马来酰亚胺（NPMI）耐热改性剂共聚物（NPISA）对提高ABS耐热性效率较高。当采用ABS粉30份,N-苯基马来酰亚胺（NPMI）耐热改性剂共聚物（NPISA）10-50份,SAN粉20～60份,能得到热变形温度在95℃～105℃之间的不同等级的耐热ABS树脂材料。     

马来酰亚胺共聚物工业化生产

日本三菱孟山都化学公司成功地开发了马来酰亚胺和苯乙烯共聚物以及马来酰亚胺和聚碳酸酯共聚物,前者的牌号称为Superex M及其阻燃级Superex V,后者     

N-(苯并环丁烯-4-基)马来酰亚胺的Diels-Alder反应及聚合物热稳定性

对N-(苯并环丁烯-4-基)马来酰亚胺(NBCBMI)单体在热引发下发生的Diels-Alder反应进行了初步探索,研究了该单体和苯乙烯(St)及N-苯基马来酰亚胺(NPMI)的自由基共聚物分别与NPMI发生的Diels-Alder反应,并对聚合物结构进行了表征分析。通过热重分析研究了Diels-Alder反应前后聚合物热稳定性的变化。结果表明,聚合物DANBCBMI初始分解温度约为500℃,600℃的热失重仅为32.21%,比NBCBMI自由基聚合产物PNB-CBMI的热稳定性有显著提高,而共聚物在发生Diels-Alder反应后的溶解性下降,但热稳定性有一定提高。     

反应温度对N-苯基马来酰亚胺-马来酸酐二元共聚物结构及性能的影响EI北大核心CSCD

以N-苯基马来酰亚胺(N-PMI)、马来酸酐(MAH)为单体,过氧化苯甲酸叔丁酯(TBPB)为引发剂,采用溶液聚合法在80～120℃合成了新型耐热改性剂N-苯基马来酰亚胺-马来酸酐二元共聚物(NMA)。通过核磁共振氢谱、傅里叶变换红外光谱对NMA进行了结构表征,证明在80～120℃之间均能制备NMA二元共聚物;采用凝胶渗透色谱法、碱液滴定法、热重分析及差示扫描量热分析对NMA二元共聚物相对分子质量、马来酸酐含量及热性能进行了分析。结果表明,当合成温度为110℃时,NMA的相对分子质量最高,相对分子质量分布最均一,热稳定性最佳;且NMA的玻璃化转化温度(Tg)随着合成温度的升高呈下降趋势。故当合成温度为110℃时,有助于N-PMI均聚结构转换为与MAH共聚结构,得到NMA二元共聚物。     

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.……     

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.……     

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.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

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     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.