偶联剂处理滑石粉填充聚乙烯薄膜的研究

目的确定最佳偶联剂及其用量,以改进聚乙烯薄膜的综合性能。方法采用铝酸酯、钛酸酯、硬脂酸等偶联剂对滑石粉进行表面改性,通过测定改性后滑石粉的接触角、活化率以及红外光谱等方法对改性效果进行评价。并将改性后的滑石粉与聚乙烯共混后进行吹塑薄膜,测定薄膜的力学性能。结果采用偶联剂改性滑石粉后,表面从亲水性变为疏水性,其中钛酸酯表面改性效果较好。表面改性提高了滑石粉填充聚乙烯薄膜的力学性能。结论使用质量分数为2%钛酸酯改性的滑石粉作为填充粉体时,聚乙烯薄膜的综合性能较好。     

铝酸酯偶联剂表面改性微晶白云母/PVC复合材料的制备及力学性能

以中国川西地区发现的一种新型矿物资源微晶白云母为原料,以铝酸酯偶联剂F-1为改性剂,对微晶白云母进行改性研究,并将表面改性后的微晶白云母加入聚氯乙烯(PVC)中制得微晶白云母/PVC复合材料。测试了改性粉体与石蜡体系的黏度及复合材料的力学性能,并采用扫描电子显微镜表征了其微观结构。结果表明,铝酸酯偶联剂F-1能有效改善微晶白云母表面与有机物质的界面结合,并且将经铝酸酯偶联剂F-1改性的微晶白云母加入PVC基体中能提高微晶白云母/PVC复合材料的力学性能,当铝酸酯偶联剂的用量为1.0%(质量分数,下同)、微晶白云母用量为15%时,微晶白云母/PVC复合材料的力学性能最好。     

竹纤维增强聚氯乙烯发泡复合材料的制备与性能

以竹纤维和聚氯乙烯为原料,加入冲击改性剂、偶联剂、发泡剂等生产助剂,通过熔融混炼挤出,最后注塑成型为复合材料试样.研究了竹粉含量、冲击改性剂含量、偶联剂和发泡剂种类对该复合材料力学性能的影响,并利用扫描电镜分析了发泡复合材料的微观结构.结果表明：竹粉在一定添加量范围内对聚氯乙烯塑料基体的力学性能具有一定的增强效果,当竹粉添加质量分数超过20％后,复合材料的力学性能开始降低;抗冲击改性剂CPE的加入,可以在聚氯乙烯/竹粉复合材料体系中形成橡胶态过渡结构,组成不均匀相,进而提高复合材料的韧性;选用的几种偶联剂中,硅烷偶联剂对复合材料力学性能的作用效果最好,马来酸酐接枝聚丙烯次之,随后是改性EVA、铝酸酯偶联剂和钛酸酯偶联剂;组合发泡剂对聚氯乙烯/竹粉复合材料的发泡效果优于单一发泡剂,当AC＋尿素的添加质量分数为1.0％,且两者的质量比为1∶1时,其作用效果最优,泡孔数量多且均匀.     

PBS/MMT纳米复合材料的制备及表征

以聚丁二酸丁二醇酯(PBS)为基材,经十六烷基三甲基溴化铵(CTAB)改性过的纳米蒙脱土为填料,采用熔融共混法,制备了PBS/MMT纳米复合材料,并研究了该复合材料的热稳定性能、力学性能和流变性能等。结果表明:当改性nano-MMT的添加质量分数为5%时,复合材料的熔点约提高了2.55℃,热初始分解温度提高了33℃;当其添加质量分数为3%时,复合材料的拉伸强度提高了9%,断裂伸长率提高了3%,冲击强度提高了23%;复合材料的流变性能比纯PBS的流变性能有一定程度的提高。     

表面处理剂对滑石粉改性聚乳酸的影响

通过改变聚乳酸(PLA)基体中滑石粉(talc)的添加量,探索滑石粉的最佳含量。在最佳含量的基础上分别用钛酸酯、硅烷偶联剂KH550和十八胺对滑石粉进行改性,研究不同表面处理剂对滑石粉/聚乳酸复合材料性能的影响。通过力学性能、差热分析(DTA)、动态再结晶和扫描电镜(SEM)等一系列测试手段对复合材料性能进行表征分析。结果表明:滑石粉含量在1%(质量分数)时,复合材料的拉伸强度达到最大值,为62.5MPa;滑石粉经硅烷偶联剂KH550改性后,复合材料的拉伸强度可进一步提高至72.1MPa。表面处理后,滑石粉/聚乳酸复合材料的结晶速率相比较处理前进一步得到提高。     

钛酸酯偶联剂改性磷石膏及其在PC/ABS中的应用

以钛酸酯偶联剂(101、201、311)改性磷石膏,测试改性磷石膏的表面吸油值和接触角,讨论不同结构钛酸酯偶联剂对磷石膏的改性效果。采用熔融挤出法制备钛酸酯改性磷石膏/PC/ABS合金,分析不同结构钛酸酯改性磷石膏对PC/ABS的力学影响。研究表明,3种钛酸酯偶联剂均能降低磷石膏表面亲水性,其中(201)偶联剂改性效果最好,其最佳改性条件:(201)偶联剂加入量为2%,反应温度为40℃。改性磷石膏作为填料填充PC/ABS,可以不同程度地提升合金体系力学性能,其中(201)改性磷石膏对改善合金体系的拉伸强度、弯曲强度效果显著,分别为45.71MPa、141.48MPa,分别比PC/ABS提高了10.04%、29.13%;冲击韧性为12.57kJ/m^2,提高了38.13%。(311)改性磷石膏填充PC/ABS合金体系时,将体系冲击韧性提高了77.91%。扫描电镜表征结果显示,改性磷石膏嵌入了PC/ABS孔洞间,其中(201)改性磷石膏分散较好。     

表面改性对可膨胀石墨填充PP/TPU复合材料的结晶行为、燃烧与力学性能的影响

研究了钛酸酯偶联剂对可膨胀石墨(EG)填充聚丙烯(PP)/热塑性聚氨酯(TPU)复合材料性能的影响。通过差示扫描量热(DSC)、热重分析(DTA)、锥形量热仪(CONE)和扫描电镜(SEM)表征方法对PP/PUT/EG复合体系的结晶行为、燃烧与力学性能进行了研究。结果表明,EG是一种有效的阻燃剂,能显著提高材料的阻燃性能。未改性的EG对PP/TPU基体有促进成核结晶作用;而偶联剂的添加削弱EG粒子对基体的这种作用。偶联剂的加入可以改善PP/PUT/EG复合材料的力学性能,当加入20phr的EG时,复合材料的拉伸强度和断裂伸长率分别由改性前的5.3MPa和17.6%提高到经改性后的5.6MPa和18.3%。     

偶联剂改性废纸/PETG生物复合材料

目的制备可生物降解的偶联剂改性废纸/PETG木塑复合材料,并检测其各方面的性能。方法分别采用偶联剂KH550,KH560和KH570对废纸粉进行改性处理,并与PETG制备木塑生物复合材料,通过傅里叶变换红外光谱、力学性能检测、吸水性能分析、扫描电镜和热重分析,研究偶联剂的加入对材料结构、力学性能、吸水性、微观形貌和热稳定性的影响。结果 KH550对复合材料性能的增强效果最好,当KH550质量分数为1%时,复合材料的拉伸强度和弯曲强度达到峰值,分别提高了32.8%和13.7%。结论偶联剂能明显改善复合材料的力学性能和热稳定性,降低其吸水率,在包装领域具有很好的应用前景。     

不同偶联剂对空心玻璃微球/酚醛复合泡沫塑料界面性能的影响EI北大核心CSCD

以不同种类的偶联剂对空心玻璃微球表面改性,改性后的微球填充酚醛树脂制备了酚醛复合泡沫塑料。研究了空心微球改性前后的表面性能和酚醛复合泡沫塑料的弯曲强度、断裂韧性以及动态力学性能的变化。结果表明:经过偶联剂处理后的空心微球,降低了空心微球之间的团聚,增加了表面疏水性,改善了与基体间的相容性和界面性能,提高了复合材料的各项性能。不同种类偶联剂中,钛酸酯偶联剂以物理缠结的方式同酚醛基体聚合物链连接,硅氧烷偶联剂除部分与甲阶酚醛中的羟甲基有化学键合作用,大部分仍以物理缠结为主,戊二醛和硅氧烷协同改性通过形成缩醛结构将微球与基体连接起来,因此,在酚醛基复合材料中以戊二醛和硅氧烷偶联剂协同改性的效果最为明显。     

不同偶联剂对空心玻璃微球/酚醛复合泡沫塑料界面性能的影响

以不同种类的偶联剂对空心玻璃微球表面改性,改性后的微球填充酚醛树脂制备了酚醛复合泡沫塑料。研究了空心微球改性前后的表面性能和酚醛复合泡沫塑料的弯曲强度、断裂韧性以及动态力学性能的变化。结果表明:经过偶联剂处理后的空心微球,降低了空心微球之间的团聚,增加了表面疏水性,改善了与基体间的相容性和界面性能,提高了复合材料的各项性能。不同种类偶联剂中,钛酸酯偶联剂以物理缠结的方式同酚醛基体聚合物链连接,硅氧烷偶联剂除部分与甲阶酚醛中的羟甲基有化学键合作用,大部分仍以物理缠结为主,戊二醛和硅氧烷协同改性通过形成缩醛结构将微球与基体连接起来,因此,在酚醛基复合材料中以戊二醛和硅氧烷偶联剂协同改性的效果最为明显。     

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.     

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...     

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.     

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 ...