Modification of Nanocomposites by Melting Intercalation of Polypropylene in Montmorillonite

The polypropylene was modified by ultraviolet irradiation.The polypropylene-montmorillonite nanoicomposites were prepared by direct melting intercalation of polypropylene powders.The structure of polypropylene,the polyproprlene irradiated,montmorllinote and polypropylene-montmorillonite composites were studied by XRD,IR and DSC.The results show that the PP molecules can are oxidized during ultraviolet irradiation,melt polypropylene can intercalate into montmorillonite layer .As a result,the layered distance(d001) of montmoril-lonite increases,and the melt absorption peak of polypropylene in layer is eliminated.     

配位插层聚合制备膨润土/聚丙烯酰胺调湿材料

通过离子交换反应先将钙基膨润土交换成钠基膨润土，继而交换成镍基膨润土，然后将丙烯酰胺配位插层进入镍基膨润土层间，于353K条件下使用硝酸铈铵作引发剂，使丙烯酰胺在膨润土中配位插层聚合5h制备出一种新型的聚丙烯酰胺／膨润土复合调湿材料。XRD分析结果表明，丙烯酰胺于338K条件下在膨润土中配位插层12h后，镍基膨润土的层间距从1．607nm增至2．079nm；同时，还通过IR分析对钙基膨润土和聚丙烯酰胺／膨润土复合物进行了表征。通过对不同膨润土含量的调湿材料调湿性能的测试表明：随着复合物中膨润土含量的增加，复合物的吸湿量和吸湿速率降低，放湿速率增加。     

EVA插层复合材料的取向结构对阻燃性能的影响

利用蒙脱土(MMT)特殊的片层结构,采用挤出工艺、熔融插层法制备了乙烯醋酸乙烯脂/蒙脱土(EVA/MMT)和乙烯醋酸乙烯脂/有机蒙脱土(EVA/OMMT)纳米复合材料,用锥形量热仪测试并分析了材料的燃烧性能。结果表明,添加OMMT的复合材料具有阻燃作用;复合材料中蒙脱土片层的(横、纵)取向影响材料的阻燃性;横向取向的EVA/OMMT复合材料有更低的热释放速率和质量损失速率,具有较好的阻燃性。通过扫描电镜(SEM)表征不同取向材料燃烧后炭渣的形貌,表明形成的炭层也为横、纵取向,解释了插层复合材料的横、纵取向对材料阻燃性的影响。     

Preparation and Properties of Phenolic Resin/Montmorillonite Intercalation Nanocomposites

1　IntroductionIntercalationcompoundingisoneoftheeffectivemethodstopreparepolymerbasecompositeswithexcellentproperties .Thepolymercanbeintercalatedintotheinor ganicmaterialswithlayeredstructures ,especiallysilicateclay ,throughintercalationcompoundingtoformthepoly merlayeredinorganicintercalationcomposites[1] .Amongmanylayeredsilicateclays ,montmorillonite (MMT)isof tenusedtopreparetheintercalationcomposites .MMTisasilicateclaymineralabundantinthenaturalworld .Itbe longsto 2∶1layeredsilica…     

聚丙烯/聚丙烯接枝丙烯酸/蒙脱土纳米复合材料的制备及性能

用悬浮接枝法制备了接枝率为2 2%的聚丙烯接枝丙烯酸作为相容剂,用十六烷基三甲基溴化铵对钠基蒙脱土进行了有机化处理,使蒙脱土的层间距从1 2nm增加到了3 84nm。通过熔融插层法制备了插层型聚丙烯/蒙脱土纳米复合材料(Polypropylene/MontmorilloniteNanocomposites,PNC),复合材料中蒙脱土层间距比有机蒙脱土的层间距又有小幅度的增加。当蒙脱土含量为2%,相容剂用量为15%时的复合材料力学性能最好,缺口冲击强度和拉伸强度分别达到12 12kJ/m2和35 77MPa,分别比纯1PP增加了180%和4 3%,蒙脱土的加入起到了增韧和增强的双重作用。     

疏水缔合聚丙烯酰胺的自组装行为

使用荧光光谱和动态光散射方法研究了疏水缔合聚丙烯酰胺(HAPAM)和聚丙烯酰胺(PAM)在水溶液中的结构和自组装行为.实验表明:HAPAM通过疏水作用,极易缔合形成聚集体,具有很低浓度的临界缔合浓度.动态光散射实验跟踪了HAPAM聚集体从小到大的生长过程,从溶液的微观结构上找到了HAPAM与PAM性能差异的根本原因.     

地区钢铁需求预测和生产能力与投资优化

本文介绍了增长曲线预测模型和部分调整优化模型,并应用增长曲线模型预测某地区钢铁需求,尝试在中国应用部分调整模型优化该地区钢铁生产能力,并对模型扩展优化该地区钢铁工业投资规模,均取得了满意的效果。     

PE/PEMA/MMT纳米复合材料的制备与性能

采用熔融插层法制备了聚乙烯／马来酸酐接枝聚乙烯／蒙脱土(PE／PEMA／MMT)纳米复合材料,研究了不同质量分数的蒙脱土对聚乙烯力学性能、热稳定性能及对有机溶剂的阻隔性的影响,并用X射线衍射法对材料的微观结构进行了表征．结果表明,聚乙烯分子链已插层进入蒙脱土层间,材料的拉伸强度最大提高了13．5％,热分解温度有一定程度的提高,材料对有机溶剂的阻隔性也有所改善、     

Effects of parameters on formation and microstructure of surface composite layer prepared by lost foam casting technique

Surface composite layer was fabricated on the AZ91D substrate using the lost foam casting (LFC) process. The pre-coating layer reacted with melt substrate and formed the composite layer, and the coating was mainly consist of alloying aluminum powder and low-temperature glass powder (PbO-ZnO-Na2O). The vacuum degree, pouring temperature, mold filling process of melt, and pre-coating thickness played an important role during the formation process of composite layer. The results show that surface morphology of composite layer can be divided into three categories: alloying effect of bad and good ceramic layer, alloying effect of good and bad ceramic layer, composite layer of good quality. The main reason for bad alloying layer is that alloying pre-coating thickness is so thin that it is scoured easily and involved in the melt, in addition, it is difficult for melt to infiltrate into the alloying coating owing to the surface tension of coating when the vacuum degree is excessively low. Bad ceramic layer is because of somewhat lower pouring temperature and the thicker alloying coating, due to the absorption of heat from the melt, making low temperature glass powder pre-coating layer fuse inadequate. Thus, to get good quality composite layer, the process conditions must be appropriate, the result shows that the optimum process parameters are as follows: at a pouring temperature of 800 ℃, vacuum degree of -0.06 MPa, alloying pre-coating thickness of 0.4 mm, and low glass powder pre-coating layer thickness of 1 mm.     

Clay-polymer Nanocomposites： Preparation, Properties, FutureApplications and New Synthesis Approach of EPDM／clay Nanocomposites

The synthetic routes, materials properties and future applications of clay-polymer nanocomposites are reviewed. Nannocomposites are composite materials that contain particles in the size rang 1-100 nm. The particles generally have a high aspect ratio and a layered structure that maximizes bonding between the polymer and particle. Adding a small quantity of these additives (0.5%—5% ) can increase many of the properties of poly-mer materials, such as tensile characteristics, heat distortion temperature, scratch resistance, gas permeability resistance, and flame retardancy. This new type of materials may be prepared via various synthetic routes comprising exfoliation adsorption, in-situ intercalative polymerization and melt intercalation. In this paper we report the new method for preparation EPDM-clay nanocomposites. The EPDM-clay nanocomposites were prepared by using two different approaches ( direct and indirect). It is found that there is no difference between both methods but the direct method is easier, its cost is lower and industrially more practical. X-ray diffraction (XRD)and transmission electron microscopy (TEM) results showed a exfoliation structure. The mechanical properties of these nanocomposites significantly improved.     

激光熔凝对4Cr5MoSiV模具钢组织及性能的影响

采用激光熔凝对4Cr5MoSiV模具钢进行了表面改性处理,研究了激光熔凝处理对模具钢组织和力学性能的影响．结果表明,材料经熔凝处理后,由表及里依次为熔凝层、淬火层、热影响区和基体．熔凝层由典型的柱状晶组成,熔凝层和淬火层之间存在一层极薄的等轴晶区;淬火层的晶粒发生细化和超细化．强化层厚度达1．1mm,平均硬度比基体提高26％,热影响区的厚度为0．3mm左右,强化层的耐磨性和耐腐蚀性显著提高．     

PU弹性网络对PAM凝胶吸水/脱水行为的影响

为改善聚丙烯酰胺凝胶(PAM)在吸水/脱水过程中对环境变化的响应性,制备了多孔聚氨酯弹性体(PU)与PAM的互穿网络结构(IPN),测试其在吸水/脱水过程中的质量和体积变化,并与PAM凝胶的响应行为进行比较,研究PU网络的回弹作用对PAM凝胶吸水/脱水行为的影响.分析表明,吸水过程中PU网络的作用主要表现为后期对溶胀网络的束缚;而在脱水过程中,其回弹行为对溶胀PAM凝胶的初期体积收缩具有明显的加速作用.这种PU/PAMIPN结构可以提高PAM作为传感/驱动器件的环境响应性.     

垃圾渗滤液生化处理出水混凝实验研究

对垃圾渗滤液生化处理出水混凝沉淀反应的主要影响因素进行了单因素实验研究,在此基础上,采用混交水平正交试验方法综合分析了实验条件对混凝沉淀处理效果的影响.所考察的因素对CODCr去除率影响的次序是：PAC投加量〉搅拌时间〉PAM投加量;优化后的实验条件：PAC投加量1200 mg/L,PAM投加量5 mg/L,搅拌时间为5 min.在优化后的混凝沉淀条件下,混凝出水CODCr去除率为60.72%,水质接近国家生活垃圾填埋污染控制标准渗滤液排放限值二级要求.     

EFFECT OF BURNING METHOD ON THE FORMING PROCESSES OF PORTLAND CEMENT CLINKER

The forming temperature of Clinker meltunderdifferent burning conditions has been studiedby appearance examination and thermal shrinkerdetermination, and the viscosity of melt has beendiscussed by studying the coordination number ofAl~(3 ) and Fe~(3 ) in cement clinker burned by differentmethod with x~- ray fluorescence analysis and Moss-bauer spectroscopy. The results show that the clin-ker melt under rapid burning may come into exis-tence at lower temperature and It's viscosity islower. So the forming processes of clinker may bedifferent at rapid burning from ordinary burning.They are probably an important factor to promote theformation of clinker burned at lower temperaturewith rapid burning method.     

Preparation of a cationic azobenzene dye-montmorillonite intercalation compound and its photochemical behavior

Montmorillonite/cationic azobenzene dye （GTL） intercalation compounds were prepared by the conventional ion exchange method. As compared with that of pure GTL, the thermal stability of the intercalated GTL was greatly enhanced, and the absorption band corresponding to azobenzene group in intercalated GTL shifted towards a longer wavelength by 55 nm, which could be ascribed to the strong conjugation of GTL supramolecular order structure （J cluster） confined in a nanoscale space of montmorillonite interlayer gallery. The microstructures of the resulting intercalation compounds could be successfully controlled by varying the amount of dye loaded as evidenced by the basal spacing of the intercalation compounds. The intercalated azo dye in the montmorillonite interlayer space exhibited reversible trans-to-cis photoisomerization and thermal cis-to-trans reaction. FTIR proved the successful intercalation of GTL into the silicate layer.     

沉淀聚合法合成聚丙烯酰胺

目的用沉淀聚合法合成聚丙烯酰胺(PAM). 方法以丙酮为溶剂, 以过氧化二苯甲酰-N,N 二甲基苯胺为氧化-还原引发剂, 采用分批加入引发剂和静态聚合合成 PAM, 研究诸因素对 PAM 相对分子质量和性能的影响. 结果合成出了具有良好水溶性、相对分子质量高于 9×105 的粉状 PAM. 结论沉淀聚合法可以直接合成具有良好水溶性的粉状 PAM; 引发剂浓度和反应温度是控制 PAM 相对分子质量的重要因素.     

聚丙烯酰胺的羟基化反应与产物结构表征

研究了聚丙烯酰胺（ＰＡＭ）及部分水解聚丙烯酰胺（ＨＰＡＭ）与甲醛的化学反应,并对产物结构进行了表征。结果显示,ＰＡＭ与甲醛的羟甲基化反应与ＰＡＭ在溶液中分子形态有较大关系,除受反应温度、时间、ｐＨ、投料比等因素影响外,聚合物浓度、羧基含量都对羟甲基化程度有明显影响。碱性条件下ＰＡＭ羟甲基化过程中伴有酰胺基的水解反应。相同反应条件下,ＨＰＡＭ的反应程度低于ＰＡＭ的反应程度。     

Boundary layer distributions and cooling rate of cooling sloping plate process

According to the principle of grain refining and slurry preparation by cooling sloping plate process, the distributions of boundary layers during melt treatment by cooling sloping plate were studied, and mathematic model of cooling rate was established. The calculation value approximately agrees with the experimental result. Laminar flow and turbulent flow exist on sloping plate surface commonly. The thickness of velocity boundary layer and the critical transfer distance from laminar flow to turbulent flow increase with the decrease of initial flow velocity. The thickness of temperature boundary layer increases with the increment of flow distance and the decrease of initial flow velocity. The melt cooling rate and melt thickness have an inverse proportion relationship. The melt cooling rate increases along the plate direction gradually when the initial flow velocity is lower than 1 m/s, the melt cooling rate keeps nearly a constant when the initial flow velocity is 1 m/s, when the initial flow velocity is higher than 1 m/s, the melt cooling rate decreases gradually. The melt cooling rate of cooling sloping plate process can reach 102-103 K/s and belongs to meta-rapid solidification scope.     

次高浊度水混凝最优GT值研究(一)──以过渡层沉速为标准

本文以聚丙烯酸胶为混凝剂,通过静水沉淀实验,以过渡层沉迷为指标,对次高浊度水的混凝囊优GT值进行研究,提出了以过渡层沉速为标准的最优GT值,同时对影响该GT值的几种因素进行了研究,得出了一些新成果．     

聚丙烯酰胺改善流态固化处理效果的试验研究

为研究聚丙烯酰胺（PAM）对流态固化土的改善作用，针对长江中下游河漫区广泛分布的软土，研究了PAM掺量、液固比、灰土比对流态固化土的影响，结果表明：PAM可以快速降低含水泥流态固化土的流动度、提高黏滞性，减缓水泥土前期的固化速度，且可用净流动度定量描述PAM对流态固化土流动性的改善效果。由此得出，不同初始液固比的流态水泥土在添加一定比例的PAM后其净流动度降低比例处于相同水平；针对液固比为70%~80%的软土，PAM掺量建议控制在0.02%~0.03%，使得流动度满足回填要求，现场施工效果较佳；同时PAM有效地提高了施工流程的自由度；在此基础上，获得了该土体动切力和流动度的关系，可以较好地拟合实测数据。