聚丙烯/蒙脱土纳米复合材料的制备与性能研究

采用十八烷基三甲基氯化铵（OTAC）和十二烷基二甲基卞基氯化铵（DDBAC）改性蒙脱土,以聚丙烯接枝马来酸酐（PP-g-MAH）作相容剂,通过熔融插层法制备了聚丙烯/蒙脱土纳米复合材料（PP/OMMT）.结果表明,PP-g-MAH能有效地改善PP与OMMT的相容性,当OTAC改性的蒙脱土（OMMT-O）用量为5wt%、PP-g-MAH用量为10wt%时,PP/PP-g-MAH/OMMT-O纳米复合材料的冲击强度为5.4 KJ/m^2,比纯PP提高了80%,极限氧指数（LOI）由PP的18提高到23.X射线衍射（XRD）测试表明,PP已经插层进入到蒙脱土片层中,部分蒙脱土产生了剥离.     

聚丙烯/蒙脱土纳米复合材料的研究进展

介绍了聚丙烯/蒙脱土纳米复合材料的制备原理及插层方法。并对国内外的研究进展进行了综述，讨论了蒙脱土对聚丙烯结晶性能的影响。蒙脱土的加入聚丙烯有异相成核的作用。另外介绍了聚丙烯/蒙脱土纳米复合材料中蒙脱土对聚丙烯力学性能的影响。其力学性能随蒙脱土含量的增加先增加后下降。     

Characterization of Solution-Mixed Polypropylene/Clay Nanocomposites without Compatibilizers

A solution mixing technique along with three organically modified montmorillonites (O-MMTs, denoted 15A, 20A and 30B), respectively, were used to prepare polypropylene (PP)-based composites. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses confirmed the O-MMTs were intercalated and/or partially exfoliated within the PP matrix to different extents. The PP/O-MMT nanocomposites were thus achieved without employing any compatibilizer. The 15A was noted to exhibit the best nano-scaled dispersion status among the O-MMTs used, which was attributed to its more organophilic characteristic. Differential scanning calorimetry (DSC) results indicated the O-MMTs improved the crystallization ability of PP slightly in the composites, whereas the melting temperature of PP hardly changed. Thermogravimetric analysis (TGA) confirmed the thermal stability enhancement of PP after adding the O-MMTs; the enhancement followed the order of PP/20A system > PP/15A system > PP/30B system. XRD results also revealed the existence of predominant α form PP crystals along with a minor amount of γ form crystals in the composites.     

Effect of Compatibilizer Type on Properties of 70:30 Polyamide 6/Polypropylene/MMT Nanocomposites

PA6/PP nanocomposites with either polyethylene octene elastomer grafted maleic anhydride (POEgMAH) or PP grafted maleic anhydride (PPgMAH) as compatibilizer were prepared using co-rotating twin-screw extruder followed by injection molding. The mechanical and microstructural properties of the composites were investigated by means of tensile, flexural, and impact testing and by scanning electron microscopy (SEM). X-ray diffraction (XRD) was used to characterize the formation of nanocomposites. The result indicated that the miscibility of PA6/PP nanocomposites was improved with the addition of POEgMAH and PPgMAH. The impact strength of PA6/PP nanocomposite with POEgMAH increased about 5 times higher than uncompatibilized composite. Increment in tensile properties was observed when PPgMAH was used as compatibilizer. XRD results revealed that PA6/PP nanocomposites were successfully formed. Uniform dispersion of PP in matrix were observed through SEM, which showed the improvement of the compatibility between polymers.     

聚丙烯/蒙脱土纳米复合材料的制备与性能研究

以马来酸酐接枝低分子量聚丙烯为相容剂,采用双螺杆挤出机熔融挤出法,制备插层型聚丙烯/有机钠基蒙脱土、聚丙烯/酸化有机化钠基蒙脱土、聚丙烯/钠基蒙脱土3种纳米复合材料,发现有机钠基蒙脱土、酸化有机化钠基蒙脱土和钠基蒙脱土对PP力学性能和燃烧性能均有一定程度的提高。经X射线衍射(XRD)和扫描电子显微镜(SEM)观察,发现有机钠基蒙脱土片层间距增幅最大,复合材料的燃烧性能也有很大提高。     

聚丙烯/蒙脱土纳米复合材料的结构及物理性能研究

采用化学反应法制备了Ziegler-Natta/有机改性蒙脱土复合催化剂,并通过丙烯单体原位插层聚合法制备出聚丙烯/蒙脱土(PP/MMT)纳米复合材料,研究了复合材料的微观结构、热性能以及加工稳定性等。结果表明,原位聚合法制备的复合材料为剥离型纳米复合材料,其中MMT片层以纳米尺寸均匀分散在PP基体中,MMT平均厚度小于10nm;随MMT含量的提高,复合材料的热稳定性提高;原位聚合制备的PP/MMT纳米复合材料在长时间剪切过程中部分MMT会发生自聚集,控制剪切时间可以有效防止MMT的自聚集;原位聚合制备的PP/MMT复合材料(粉料)中,PP以α晶型为主,纳米MMT的引入并不会诱导生成聚丙烯β晶型,复合材料中β晶型的出现与退火条件有关。     

复合载体法制备聚丙烯-蒙脱土复合材料

将传统Z-N催化剂TiCl4负载于蒙脱土．乙醇镁复合载体上,进行丙烯常压原位聚合,制备聚丙烯-蒙脱土纳米复合材料,克服了单-蒙脱土作载体时聚合活性低、产物分子量小的缺点。对比不同制备过程的催化剂,发现TiCl4的后处理可以大幅提高催化活性。引入苯乙烯可有效降低Mg—MMT／Mg(OEt)2/TiCl4/EB体系制备的Cat5催化聚合时所需的Al／Cat比。由Mg—MMT／Mg(OEt)2/Ti(OBu)4/TiCl4/EB体系制备的Cat6具有活性高,所需Al／Cat低的优点,为合适的制备聚丙烯-蒙脱土纳米复合材料的催化剂。WAXS和TEM表明复合材料中蒙脱土主要呈剥离杰分散干聚丙烯基体中。产物的熔点和商用聚丙烯的熔点接近。     

Morphological,Thermal and Mechanical Properties of Polypropylene and Vermiculite Blends

Morphological, thermal and mechanical properties of blends prepared from polypropylene (PP) and 1, 3 and 5 wt% of vermiculite (VMT) were studied. The samples were prepared in a twin-screw extruder. The addition of maleic anhydride-functionalized polypropylene (PP-g-MAH) was also investigated. The blend morphologies were determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The thermal properties of the composites were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The DSC results showed that PP crystallizes on cooling at higher temperatures as VMT content increases. The increase in crystallization temperature was most evident for blends with 5 wt% VMT. The TGA results showed that the use of VMT particles to fill polypropylene increased the thermal stability of the composite. The mechanical properties, tensile modulus and tensile strength at yield point of the PP improved by the presence of VMT.     

Morphological and Thermal Properties of ABS/Montmorillonite Nanocomposites Using ABS with Different AN Contents

Acrylonitrile‐butadiene‐styrene (ABS)/clay nanocomposites have been prepared using two types of ABS with different AN contents and a chemically modified clay, Cloisite 20A. The composites were prepared by melt mixing in a twin‐screw extruder. Their morphological properties were characterized by XRD and TEM. The thermal stability of the polymer nanocomposites was studied using TGA and flammability tests. The results were analyzed in terms of the effect of the clay content and the type of ABS used on the clay dispersion and the thermal stability of the nanocomposites. Experimental results confirmed that better dispersion and intercalation and/or exfoliation can be obtained when using an ABS with a higher AN content. The study using TGA and flammability tests showed that the nanodispersed layers of silicate enhanced the thermal stability of the ABS matrix, and that an ABS with higher AN content was more effective in providing fire retardancy. This suggests that when using higher AN contents, more polar groups are present within the polymer matrix, allowing a more homogeneous dispersion and intercalation of the chain polymers into the organomodified montmorillonite clay (MMT), and even some exfoliation of the nanoclay.

     

Structural, Dielectric, and Thermal Properties of Strontium Barium Niobate-Doped Fused Silica Nanocomposites

Ferroelectric strontium barium niobate (SBN)-doped Na₂O–B₂O₃–SiO₂ (NBS) glass nanocomposites were prepared by dispersing sol–gel-derived SBN powder into fused NBS glass. Their structures were characterized by X-ray diffractometry and Raman spectroscopy. The dielectric constants were measured as functions of frequency and temperature using an impedance analyzer. The ferroelectric-to-paraelectric-phase transition was studied by differential scanning calorimetric analysis. Our results revealed that the embedded SBN has lower phase transition temperature and phase transition heat than those of SBN bulk materials. Their activation energy, however, is larger than that of SBN ultra-fine powders. Pure tetragonal-phase SBN nanocomposites can be obtained at annealing temperatures of 750°–1000°C. Their dielectric constants are ∼32–46 and ∼20–25 at low frequencies and radio frequencies, respectively, and the loss tangent is <0.1 at room temperature in the radio frequencies range. Our studies suggested that additional reduction in the loss properties must be made before these systems can be considered for application as microwave dielectric materials.     

PP／废旧橡胶／SBS复合材料的制备和力学性能研究

通过磨盘型力化学反应器制备PP/废旧橡胶(WTR)复合粉体，然后与SKS共混制备PP/WTR/SBS复合材料。研究了材料的力学性能、微观结构和共混物的加工性质。结果表明：当SBS添加量在20％～25％时，PP/WTR/SBS复合材料的力学性能较PP/WTR有了很大的提高，当SBS用量为25％时，断裂伸长率提高了365％，冲击强度提高了73．2％，而体系的拉伸强度基本不变。复合材料冲击断面的形貌和复合体系流变性能研究结果表明：磨盘碾磨可有效改善各组分间的混合性能，提高相容性并有效改善材料的加工性能。     

Solution Intercalation and Relaxation Properties of Maleated Polypropylene/Organoclay Nanocomposites

In this work we report the investigation of the dynamics of maleic anhydride grafted polypropylene (PPgMA) and PPgMA-based nanocomposites by means of dielectric relaxation spectroscopy (DRS) and dynamic mechanical thermal analysis (DMTA). After characterization of neat PPgMA, we study the effect of organically modified silicate filler on the dynamics of PPgMA with dynamic mechanical thermal analysis. Our results suggest that the β-relaxation process, corresponding to the glass transition of PPgMA, is affected by the clay loading. The glass-transition temperature of PPgMA increases in a composition with filler content of 30 wt.%, probably because of polymer-filler interactions, which reduces the polymer chain mobility.

In the nanocomposite materials a separate high temperature process due to Maxwell-Wagner-Sillars (MWS) polarization was observed with dielectric relaxation spectroscopy.     

聚丙烯/石墨烯复合材料的制备及性能研究进展

介绍了几种石墨烯的制备方法,包括微机械剥离法、液相或气相直接剥离法（物理方法）,化学气相沉积法、碳纳米管剖开法、外延生长法、还原氧化石墨法（化学方法）,并阐述了这几种方法的优缺点。其次总结了聚丙烯/石墨烯纳米复合材料的制备方法,重点讨论了石墨烯对不同方法制备的复合材料电学、力学、热学、结晶及流变性能的影响,最后展望了石墨烯在聚丙烯材料改性中所面临的问题及其聚丙烯/石墨烯复合材料的应用前景。     

Thermal and Antistatic Properties of Polypropylene/Organo Montmorillonite Nanocomposites

Both polypropylene (PP) and PP/organo-montmorillonite (OMMT) masterbatch containing antistatic agent (3–9 wt%) were prepared by using co-rotating twin screw extruder followed by injection molding. PP/OMMT masterbatch was prepared by mixing PP, OMMT and maleated PP (PPgMAH). The PP nanocomposites were characterized by using X-ray diffractometer (XRD), differential scanning calorimeter (DSC), thermogravimetry analyzer (TGA), hardness and surface resistivity tests. XRD results indicated that AA could promote the intercalation in PP/OMMT nanocomposites. The decomposition temperature of PP/OMMT/AA nanocomposites is higher than that of PP/OMMT. The hardness, degree of crystallinity and surface resistivity of PP nanocomposites was influenced by the addition of antistatic agent.     

聚丙烯／聚苯乙烯／蒙脱土纳米复合材料的制备

通过对钠基蒙脱土的有机化处理，有机土与聚苯乙烯的复合，聚苯惭烯／蒙脱土复合材料与聚丙的复合等三个步骤制备出了聚丙烯／聚苯乙烯／蒙脱土纳米复合材料。     

Preparation of Nanocomposites of Polypropylene/Alkylaluminum-modified Clay: Effect of Polymer Grade,Amount of Clay,and Screw Speed

Bentonite was modified with trialkylaluminum to prepare polypropylene/clay nanocomposites. Treated clay, commercial polypropylene, and a coupling agent were mixed in miniextruder. To obtain the masterbatches and dilutions, two polypropylene grades were used to analyze the influence of molar mass on clay dispersion. The screw rotation varied from 30 to 200?rpm, and the clay content was 1, 2, and 5?wt%. For samples prepared with higher molar mass, increasing speed from 30 to 200?rpm improved the clay dispersion. For processing with lower molar mass, decreasing speed from 60 to 30?rpm caused an increase in viscosity, resulting in better dispersion.     

聚丙烯／蒙脱土纳米复合材料研究进展

简要介绍了蒙脱＋（MMT）的结构、插层原理和表面修饰方法,并介绍了聚丙烯（PP）／MMT纳米复合材料的制备原理和方法。综述了PP／MMT纳米复合材料的国内外研究进展。     

反应性增容剂对PP／纳米SiO2复合材料力学性能的影响

以氨基功能化聚丙烯（PP-g-NH2）作为PP／纳米SiO2复合材料的反应性增容剂，研究了其对复合材料力学性能的影响。结果表明，反应性增容剂的加入能较大幅度提高纳米复合材料的拉伸强度、拉伸模量，尤其是冲击性能，在环氧功能化改性纳米SiO2粒子含量为3％、反应性增容剂含量为10％时，冲击强度提高87％，拉伸强度提高了13％，表现出明显的增强增韧作用。     

石墨烯/聚丙烯纳米复合材料流变与拉伸性能

采用熔融共混法制备了多种粒径、不同含量的石墨烯(GNP)/聚丙烯(PP)纳米复合材料,通过流变实验和拉伸实验分别研究了GNP粒径和GNP含量对复合材料流变特性的影响以及注塑成型工艺参数(注塑温度、注射压力、注射速度及背压)对复合材料拉伸性能的影响。研究结果表明,GNP微粒能够显著改善PP基体的抗拉强度,在一定含量范围(3%~9%)和较大粒径(40μm)时,会对PP熔体的流动性产生较大影响。虽然,注塑成型工艺参数对GNP/PP复合材料的抗拉强度影响较小,但是,其对材料的韧性影响较大。随着注塑的温度、压力、速度和背压的升高,材料韧性呈先增后降的趋势,最优参数组合为注塑温度215℃、注射压力60 MPa、注射速度50%、背压压力1 MPa。