扩链剂对环氧聚氨酯复合乳液性能的影响

以甲苯二异氰酸酯(TDI-80)、聚醚二醇(N220)、三乙胺(TEA)为原料,1,4丁二醇(BDO)、乙二胺(EDA)为小分子扩链剂,二羟甲基丙酸(DMPA)为亲水扩链剂,环氧树脂E-20为大分子扩链剂,合成了环氧聚氨酯复合乳液,讨论了几种扩链剂对合成的乳液性能的影响.结果表明,乳液的黏度、涂膜的硬度、拉伸强度随BDO、EDA、DMPA和E-20用量的增加而增大;乳液的外观和稳定性随BDO、EDA和E-20用量的增加变差,随DMPA的用量增加而变好;涂膜的吸水率随BDO和E-20用量的增加而减小,随EDA和DMPA用量增加先减小后增大.当BDO的添加量为6％、EDA为0.5％、DMPA为6％、E-20为5％～8％时,所制得的环氧聚氨酯复合乳液性能较好.     

涂料用有机硅、环氧复合改性水性聚氨酯的制备

选用异佛尔酮二异氰酸酯(IPDI)、聚己二酸1,4-丁二醇酯(PBA)、二羟甲基丙酸(DMPA)、1,4-丁二醇(BDO)为主要原料,用双酚A型环氧树脂和氨基硅烷复合改性制备水性聚氨酯。研究了体系中n(—NCO)∶n(—OH)、DMPA用量、环氧树脂与氨基硅烷的配比对乳液及涂膜的影响,并通过傅里叶红外光谱仪、粒径分析仪、接触角仪和热重分析仪(TGA)对乳液及涂膜进行了表征。结果表明:n(—NCO)∶n(—OH)为1.5∶1,DMPA用量为5%~7%,环氧树脂添加量为8%,氨基硅烷的用量为4%时,乳液外观及稳定性好,平均粒径为24.56nm;涂膜硬度达2H,吸水率仅为2.3%,耐热性显著提高;综合性能优异,可作为防腐蚀涂料用树脂,应用于多领域。     

亲水扩链剂和中和剂对环氧聚氨酯乳液性能的影响

以二羟甲基丙酸(DMPA)作为亲水扩链剂,三乙胺(TEA)为中和剂,环氧树脂为大分子扩链剂,合成了环氧聚氨酯复合乳液(PUE)。讨论了DMPA和TEA的加入方式、DMPA的含量及中和度对PUE乳液及涂膜性能的影响。结果表明:随着DMPA用量和中和度的增加,PUE乳液的外观、稳定性变好,粘度增大,粒径减小,涂膜的硬度和拉伸强度提高;吸水率随着DMPA用量的增加先减小后增大,随中和度的提高而增大。把质量分数为6%的DMPA溶于NMP,在反应后期加入到体系中,当中和度为90%～100%,采取后中和的工艺时,可得到综合性能较好的PUE乳液。     

聚氨酯-环氧树脂复合乳液的合成与性能

以甲苯二异氰酸酯(TDI)、聚醚二元醇(N220)、环氧树脂(E20)为原料合成了聚氨酯-环氧树脂复合乳液(WPUE)。研究了NCO/OH摩尔比、交联剂(TMP)用量、环氧树脂(E20)用量、亲水扩链剂(DM-PA)用量对乳液及涂膜性能的影响。用红外光谱(FT-IR)、热重分析(TG)和差示扫描量热分析(DSC)对膜的结构和热稳定性进行了表征。结果表明,当NCO/OH摩尔比为1.2~1.4,TMP用量为2.5%~3%,E20用量为4%~6%,DMPA用量为7%~9%时,乳液储存期可达12个月,其涂膜具有较好的性能:硬度0.67,拉伸强度11.6 MPa,吸水率约为6.8%,主要性能均优于WPU。     

含氟丙烯酸酯改性水性聚氨酯纳米复合乳液制备及性能研究

用含氟丙烯酸酯改性水性聚氨酯，乳液共聚法获得具有核壳结构的水性PUA纳米复合乳液，详细考察了PU／PA质量比、HEA用量、DMPA用量等对乳液涂膜性能的影响；实验结果表明该乳液粒径在100nm左右，乳液涂膜具有良好的力学性能，当含氟单体含量为5％时，其表面自由能为20．8mJ·m^-2，耐水性能也得到显著提高。     

含氟硅聚氨酯-丙烯酸酯复合乳液的合成

以异佛尔酮二异氰酸(IPDI)、聚丙二醇(PPG)、端羟丙基硅氧烷(PDMS)、二羟甲基丙酸(DMPA)及1,4-丁二醇(BDO)为主要原料,采用溶液聚合法合成有机硅改性水性聚氨酯(SiPU)。以SiPU为种子乳液,并作为复合乳液的壳层,加入核层单体丙烯酸丁酯(BA)、甲基丙烯酸甲酯(MMA)及甲基丙烯酸十二氟庚酯(DFMA),通过乳液聚合得到氟硅改性聚氨酯-聚丙烯酸酯(FSiPUA)复合乳液。考察了PDMS及DFMA用量对乳液聚合过程及乳胶膜表面疏水性能的影响。采用FT-IR、CA、TEM、DSC及TG等表征复合乳液涂膜结构与性能。结果表明,FSiPUA复合乳液呈现核壳结构,在PDMS和DFMA的协同作用下,当PDMS和DFMA用量分别为m(PDMS)/m(PU)=5.5/100和m(DFMA)/m(AA)=15/100时,涂膜的表面自由能低至21.67 mN/m,对去离子水接触角达102.3°,涂膜耐热性有一定提高。     

聚氨酯乳液互穿聚合物网络的制备与结构

以甲苯二异氰酸酯(TDI)、聚己二酸丁二醇酯(PBA2000)和环氧树脂(E-20)为主要原料,制备了高环氧树脂含量的聚氨酯(PU)/环氧树脂(EP)乳液互穿聚合物网络(LIPN)。通过红外光谱,动态力学分析,透射电镜等研究了产物的结构与性能。结果表明,LIPN已形成,乳液乳胶粒子为非核壳结构,EP和PU两种组分完全互容且在分子尺度互穿。改性PU的耐溶剂性大幅提高,表现出明显的互穿协同效应。可作为一种新型的环保PU涂层应用于各个领域。     

聚氨酯-环氧双重改性丙烯酸酯乳液及其压敏胶的研究

以不饱和 C C 键封端的聚氨酯预聚体(PU)和环氧树脂来改性丙烯酸酯,通过两步接枝共聚合成聚氨酯-环氧复合改性的丙烯酸酯(PUEA)水性压敏胶(PSA)。 通过差示扫描量热(DSC)和透射电镜(TEM)分析发现,改性后的共聚物为一均相体系,组分间未发生相分离。 研究了 PU 加入量和聚合工艺对乳液性能的影响,结果表明,改性后 PUEA 的粘接性、耐高温性有明显提高,当 PU 加入量为 6% 时 PSA 乳液的综合性能较佳;采用化学共聚所得共聚物比物理共混所得乳液的稳定性、粘接性和耐高温性有显著提高。     

蓖麻油-丙烯酸酯改性的双组分水性聚氨酯胶粘剂研究

以聚醚多元醇(N220)、甲苯二异氰酸酯(TDI-80)、蓖麻油(C.O)、甲基丙烯酸甲酯(MMA)为主要原料,合成了蓖麻油改性的水性聚氨酯(WPUCA)复合乳液.向该复合乳液中加入固化荆,得到复合软包装用双组分改性水性聚氨酯胶粘剂.研究了蓖麻油的添加量以及丙烯酸酯和聚氨酯比例对改性后乳液及胶膜各项性能的影响,同时研究了多异氰酸酯固化剂用量及固化时间时胶粘剂粘结性的影响.实验结果表明,蓖麻油的添加量为3.0%(质量分数),PA、PU质量比为1:2,固化荆含量为6%(质量分数),固化时间为4h,胶粘剂的性能达到较佳.     

环氧改性水性聚氨酯的合成及因素分析

用异佛尔酮二异氰酸酯(IPDI)、聚丙二醇2000(PPG2000)、2,2-双(羟甲基)丙酸(DMPA)为主要原料合成预聚体,环氧树脂(E44)开环合成环氧改性水性聚氨酯(EWPU),考察了不同影响因素对EWPU乳液及胶膜性能的影响。首先,通过FT-IR证实了环氧改性水性聚氨酯的合成;然后,经过TG测试证明了改性后水性聚氨酯耐热性能优于水性聚氨酯;最后详细探究了DMPA量、—NCO与—OH的摩尔比(R值)、硬单体配比以及环氧量对EWPU乳液粒径、贮存稳定性、涂膜耐水性、涂膜耐磨性和力学性能的影响。结果表明,当DMPA量为5%、R值为1.5、硬单体配比为35%、EP量为8%时,EWPU乳液的综合性能最优。     

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