顺酐化EPDM的合成及其对聚甲醛／顺丁橡胶的增容作用

在ＥＰＤＭ，顺丁烯二聚酐的二甲苯溶液中，加入质量浓度为０．０２５ｋｇ／Ｌ的引发剂过氧化苯甲酰，在１００－１３９℃下进行顺酐化反应，可制备顺酐化ＥＰＤＭ。结果表明，在ＢＰＯ／ＥＰＤＭ为０．００６，ＭＡＨ／ＥＰＤＭ为０．２８４时，产物结构ＭＡＨ质量分数约２０％，ＭＡＨ利用率约７０％。     

PE—MAH的合成及其对PE／NBR的增容作用

聚乙烯（ＰＥ），马来酸酐（ＭＡＨ）和过氧化二异丙苯（ＤＣＰ）在溶液中反应，其产物经多次纯和红外光谱分析证明，ＭＡＨ以化学链连接到ＰＥ分子链上，接枝率达０．５ＭＡＨ／１００Ｅ，即相当平均每个ＰＥ上接枝有１０个ＭＡＨ。用不同接枝率的聚乙烯接枝马来酸酐聚物（ＰＥ－ＭＡＨ）作为极性差别较大的ＰＥ和丁腈橡胶（ＮＢＲ）的相容剂，分别研究其接枝率和用量对共混物的拉伸强度和低温冲击强度的影响，结果发现：ＰＥ－ＭＡ     

熔融挤出接枝法制备HDPE／PA1010增容剂MPE

本文介绍用ＤＣＰＯ作引发剂，通过熔融挤出接枝法制备ＨＤＰＥ／ＰＡ１０１０共混体系增容剂ＭＰＥ的工艺研究。实验结果表明，通过熔融挤出法可将ＭＡＨ单体接枝于ＨＤＰＥ，接枝率和ＭＩ受挤出温度、螺杆转速、ＤＣＰＯ和ＭＡＨ用量的影响，其最佳工艺条件为：挤出温度范围１８０～２２０℃，螺杆转速２５ｒ／ｍｉｎ，ＤＣＰＯ和ＭＡＨ用量分别为０．３份和１．０～１．３份（树脂用量为１００份）。文中还对ＨＤＰＥ融熔挤出接枝     

低密度聚乙烯接枝烯基双酚A醚对HDPE／PC共混体系性能的影响

本文采用烯基双酚Ａ醚接枝低密度聚乙烯（ＬＤＰＥ－ｇ－ＤＢＡＥ）作为高密度聚乙烯／聚碳酸酯（ＨＤＰＥ／ＰＣ）共混体系的增容剂,初步研究了ＬＤＰＥ－ｇ－ＤＢＡＥ对ＨＤＰＥ／ＰＣ体系性能的影响。通过对共混物形态观察、耐热性能及力学性能测试,发现ＬＤＰＥ－ｇ－ＤＢＡＥ对ＨＤＰＥ／ＰＣ体系有良好的增容效果;并发现了增容剂的最佳用量质量比大致为１０％,提高增容剂的接枝率更有利于改善共混物的性能。６５／３５ＨＤＰＥ／ＰＣ共混物的ＨＤＴ为９２℃,拉伸强度３０２ＭＰａ,冲击强度２９８ｋＪ／ｍ２,分别比未加增容剂时的８２℃,２７３ＭＰａ和１５５ｋＪ／ｍ２有较大提高。     

聚乙烯固相接枝马来酸酐的研究

研究了以过氧化苯甲酰（ＢＰＯ）为引发剂,二甲苯为界面剂,粉状聚乙烯（ＨＤＰＥ、ＬＬＤＰＥ）固相接枝马来酸酐（ＭＡＨ）的反应。讨论了反应温度、引发剂用量、单体用量和界面剂种类等对接枝反应的影响,并用红外光谱法证实了接枝反应。结果表明,ＰＥ固相接枝ＭＡＨ反应对温度敏感,随温度升高,接枝率提高;在一定范围内,接枝率随引发剂用量、单体用量和搅拌转速、界面剂用量的增加而提高;界面剂用量虽少,但能促进ＢＰＯ、ＭＡＨ在ＰＥ上的反应。通过接枝反应可得到接枝率为９％左右的ＰＥ－ｇ－ＭＡＨ产物和接枝率为１３％以上的ＬＬＤＰＥ－ｇ－ＭＡＨ产物     

NBR／EPDM共混橡胶

ＮＢＲ／ＥＰＤＭ共混橡胶《弹性体》１９９３，№１报导，北京化工学院利用商品化高聚物ＥＶＡ－１４作增容剂，制得了优异机械性能的ＮＢＲ／ＥＰＤＭ共混胶。胶料配方为：ＮＢＲ６０，ＥＰＤＭ３０，ＥＶＡ－１４１０，ＨＡＦ３０，ＤＢＰ１０，防ＲＤ１．０，ＺｎＯ５...     

阻隔性HDPE／MPE／PA1010共混体系的研究

用挤出法以马来酸酐（ＭＡＨ）接枝高密度聚乙烯（ＨＤＰＥ）为增容剂（ＭＰＥ），ＰＡ１０１０为阻隔组分，ＨＤＰＥ为基料，制取了ＨＤＰＥ／ＭＰＥ／ＰＡ１０１０共混材料。研究了挤出温度、ＭＰＥ用量、ＰＡ１０１０含量对其阻隔性能的影响，比较了几种不同渗透体系的吸油率和渗透损失量。     

EPDM—g—MMA接枝率对POM／EPDM共混物增容作用的影响

本文介绍以ＢＰＯ为引发剂，合成接枝共聚物ＥＰＤＭ－ｇ－ＭＭＡ的方法，并对其进行红外表征，另外，借助ＳＥＭ和力学性能测试研究了接枝率时ＰＯＭ／ＥＰＤＭ共混物的增容作用的影响。     

E/VAC与马来酸酐反应挤出接枝的研究

用同向双螺杆挤出机进行Ｅ／ＶＡＣ熔融接枝ＭＡＨ的反应。考察了单体、引发剂用量和加工条件对接枝率及熔体流动速率的影响。结果表明,在Ｅ／ＶＡＣ接枝ＭＡＨ的反应中,接枝率随着ＤＣＰ用量、ＭＡＨ用量以及螺杆转速的增加出现峰值,较佳的实验配方为Ｅ／ＶＡＣ：ＭＡＨ：ＤＣＰ＝１００：２：０．２。接枝反应对Ｅ／ＶＡＣ的流动性有很大影响,接枝物的熔体流动速率随ＤＣＰ用量的增加而下降。     

矿用电缆半导电屏蔽层胶料的研制

简介了矿用电缆半导电屏蔽层胶料的研制。ＮＢＲ半导电屏蔽层胶料配方为：ＮＢＲ２７０７ １００;导电填料 １００;氧化锌 １０．０;促进剂ＴＭＴＤ ４．０;邻苯二甲酸二辛酯（ＤＯＰ） ２３．０;其余配合剂 １３．０,合计２５０．０。乙烯醋酸惭烯酯橡胶（ＥＶＡ）半导电屏蔽层胶料配方为：ＥＶＡ（Ｌｅｖａｐｒｅｎ５６０） １００;导电填料 １００;过氧化二异丙苯 ３．０;三烯丙基异氰酸酯 ３．０;ＤＯＰ／邻     

混杂纤维对摩擦材料性能影响的研究

本文采用腰果壳油、三聚氰胺改性粉末酚醛树脂为基体,陶瓷纤维、钛酸钾晶须和kevlar纤维混杂制备制动摩擦材料,研究了不同混杂纤维含量对摩擦材料摩擦磨损性能影响。结果表明,增强纤维含量过低或者过高均会导致摩擦材料摩擦性能的降低。陶瓷纤维、钛酸钾晶须和kevlar三种增强纤维混杂使用能够提高并稳定制动摩擦材料的摩擦系数,对降低摩擦材料的磨损率有明显的作用。推荐在纤维混杂摩擦材料配方中采用25％的纤维含量和3％的Kevlar纤维含量。     

Effect of Y2O3 addition on tribological properties of plasma sprayed Al2O3-13% TiO2 coating

The effect of Y₂O₃ addition on structure, mechanical properties and tribological properties of Al₂O₃-13 wt% TiO₂ coating was investigated. The addition of 20 wt% Y₂O₃ resulted in better densification, stabilization of alpha (α) alumina phase and improvement in fracture toughness of Al₂O₃-13 wt% TiO₂ coating. Abrasive wear tests were performed over a range of loads and sliding speeds. The stabilization of α alumina phase further increased with an increase in severity of wear test conditions, as noted from X-Ray Diffraction (XRD) and X-Ray Photoelectron Spectroscopy (XPS) analysis of worn coatings. Al₂O₃-13 wt% TiO₂-20 wt% Y₂O₃ coating displayed lower friction coefficient and lower abrasive wear rate than Al₂O₃-13 wt% TiO₂ coating, which was due to synergistic effect of α alumina phase and formation of magneli phase oxide of titanium; Ti₂O₃. Friction energy map was used to rationalize observed wear rates, to identify different regimes of wear and degradation modes of coatings.     

不同种类酚醛树脂黏结剂对摩擦材料性能的影响

分别以未改性通用酚醛树脂、特殊改性刹车片专用酚醛树脂、腰果壳油改性酚醛树脂、丁腈橡胶改性酚醛树脂为黏结剂,玄武岩纤维、钢纤维为增强纤维制备四种酚醛树脂基摩擦材料。对试样进行物理性能、机械性能和摩擦磨损性能测试。结果表明,四种摩擦材料的密度相差不大,未改性通用酚醛树脂基摩擦材料的硬度符合刹车片使用要求,腰果壳油改性酚醛树脂基摩擦材料具有最佳的冲击强度和压缩强度;在摩擦过程中,腰果壳油改性树脂摩擦表面形成碳化膜,碳化膜的存在使摩擦材料的摩擦系数相对比较稳定,降低了磨耗量。研究表明,腰果壳油改性树脂基摩擦材料的综合性能最优。     

Wear damage of Si3N4-graphene nanocomposites at room and elevated temperatures

Mechanical and tribological properties of nanocomposites with silicon nitride matrix with addition of 1 and 3 wt.% of multilayered graphene (MLG) platelets were studied and compared to monolithic Si₃N₄. The wear behavior was observed by means of the ball-on-disk technique with a silicon nitride ball used as the tribological counterpart at temperatures 25 °C, 300 °C, 500 °C, and 700 °C in dry sliding. Addition of such amounts of MLG did not lower the coefficient of friction. Graphene platelets were integrated into the matrix very strongly and they did not participate in lubricating processes. The best performance at room temperature offers material with 3 wt.% graphene, which has the highest wear resistance. At medium temperatures (300 °C and 500 °C) coefficient of friction of monolithic Si₃N₄ and composite with 1%MLG reduced due to oxidation. Wear resistance at high temperatures significantly decreased, at 700 °C differences between the experimental materials disappeared and severe wear regime dominated in all cases.     

CH小包透明纸包装机制动装置改造

GD包装机组在我厂卷包车间投入生产已经十多年,CH小包透明纸包装机置于主机X1(X2)之后,其作用是在烟包外再包裹一层透明纸,使之密封,防潮、延长存放期和美化外观,提高产品附加值。其中CH小包透明纸包装机制动装置与制动鼓为刚性接触,较容易被磨损,为了满足产品工艺要求和降低小包透明纸输送不稳定引起的故障停机次数必须经常对其进行更换,因此找到合适的制动装置取代原有的制动装置已是当务之急。改造后,新的制动装置为包装机组淘汰下来的输送皮带,与制动鼓为弹性接触,不易被磨损,并且制动装置对纸圈的制动摩擦力与透明纸牵引力在工作过程中总处于动态平衡状态,对该部位的改造取得了预期的效果,不仅提高了小包透明纸的包装质量,还对包装机组的设备有效作业率的提高起到了积极推动作用。     

Analytical expressions for transient melting of polymer pellet sliding against adiabatic wall

The melting of polymer caused by friction before the solid plug is formed is an important phenomenon in the plastic injection process. To analyze the melting process caused by solid particles sliding against the bellow, a method that can simulate behavior of each particle during the calculation should be used. Particle element numerical method is hence adopted in the analysis for this research to take into consideration the behavior of each particle, where the melting of pellets caused by friction against flight and screw are assumed as friction against adiabatic walls. In this paper, analytical expressions of the transient melting process for spherical polymer pellets sliding against adiabatic wall are derived, which is essential for the numerical simulation of melting process in solid conveying section by particle element method.     

Friction of polystyrene: Consequence on nano-wear

Friction is able to induce major consequences on surface polymer properties (wear, scratch, etc.). These problems are crucial in the case of organic coatings (paints, varnish). The aim of this work is to analyse the influence of friction on the nano-wear behaviour of polystyrene. Studies will be focused on the analysis of the transfer layer induced by the friction of a polystyrene cylinder in contact with a flat and smooth substrate. The model substrate is a hydrophilic silicon wafer (hydroxylated by a piranha treatment). Friction experiments are performed with a translation tribometer which measures the tangential force between the polymer and the substrate for controlled normal force and friction speed. The transfer layer is analysed using atomic force microscopy (AFM). Tentative correlations between transfer layer characteristics and polymer properties are proposed.     

Adhesion and friction behaviours of polydimethylsiloxane - A fresh perspective on JKR measurements

The self-adhesion of a variety of polydimethylsiloxanes (PDMS) has been investigated using a newly developed JKR apparatus that can also determine the associated friction behaviour of the same sample. The results have been interpreted using the complete JKR model by incorporating the indentation data also in the analysis. By varying the molecular mass M_c of PDMS from 6 to 28 kg/mol the elastic modulus E decreases from 1.16 to 0.71 MPa while the work of adhesion remains about constant. In contrast measurements of the friction of the same systems indicate an increase of the friction force. Introduction of dangling chains leads to a strong decrease of E from 1.16 to 0.56 MPa for low M_c and from 0.71 to 0.09 MPa for high M_c and again only to minor changes in W. The latter results can be understood from an inward distribution of the dangling ends.     

Nano-scale friction of polystyrene in air and in vacuum

Using atomic force microscopy (AFM), we measured friction between an AFM tip and a polystyrene surface at 25 °C, as a function of the sliding velocity and the applied normal load, both in air and under vacuum conditions. The objective was to analyze the influence of humidity on the frictional behavior of polystyrene. Our experimental results as a function of sliding velocity revealed a logarithmic increase of the friction force in air whereas a logarithmic decrease of this force is found in vacuum. Our comparative results unveil that two different dissipation mechanisms are dominating the frictional behavior of polystyrene in air and in vacuum. We propose a tentative explanation.     

Preparation and tribological properties of graphene/TiO2 ceramic films

Single and multiple-layer TiO₂ (GT) ceramic films with graphene nanoplatelets were obtained by sol-gel method. X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), UV–vis diffuse reflection spectroscope and atomic force microscope (AFM) were used to investigate the structure. Interestingly, the GT ceramic films were decorated by graphene nanoplatelets on surface and at interlayer. After heat treatment, graphene kept non-oxidized. The tribological properties of GT ceramic films were investigated using a reciprocating ball-on-plate configuration. The GT ceramic films show excellent antifriction and abrasion resistant properties that the minimum frictional coefficient approximates to 0.1. With more graphene quantity, less frictional coefficient and larger abrasive resistance were observed. When the graphene quantity keeps equally, the frictional coefficient decreases with layers of ceramic film. At high temperature, the frictional coefficient shows a decrease tendency, which reaches the minimum at 100 °C.