有机蒙脱土与MCM-41介孔分子筛的共同填加对聚丙烯基复合材料性能的影响

以纳米有机蒙脱土(OMMT)、MCM-41纳米介孔分子筛(不含模板剂)、OMMT/MCM-41混合物(m(OMMT):m(MCM-41)=1:1)为填料(增强组分),通过双螺杆挤出机制备了聚丙烯(PP)基纳米复合材料;考察了填料种类及添加量对纳米复合材料性能的影响。实验结果表明,以OMMT/MCM-41混合物为填料时,两种粒子起到了协同增强、增韧的作用;当OMMT/MCM-41混合物的添加量(以体系的总质量计)为2.0%时,PP基纳米复合材料的拉伸强度和冲击强度达到最大值,分别为45.1MPa和38.6kJ/m2,比PP分别提高了30%和53%;同时添加OMMT和MCM-41的PP基纳米复合材料的热稳定性高于单独填加OMMT或MCM-41的PP基纳米复合材料。     

纳米黏土和多壁碳纳米管的载体化成型及其负载Ziegler-Natta催化剂的研究

通过喷雾干燥、SiO2纳米胶粒改性和造孔改性等手段制备形态和结构可控的成型纳米颗粒(纳米黏土颗粒和碳纳米管颗粒),并以其为载体负载Ziegler-Natta催化剂。采用SEM、TEM和比表面积测试等手段,对成型纳米颗粒及催化剂的形态、结构和性能进行表征。实验结果表明,通过调节喷雾干燥过程中料液固含量、进料速率、进气温度和进气压力等参数,可将纳米黏土或碳纳米管成型为球形颗粒;当SiO2纳米胶粒用量为5%(w)、碳酸氢铵用量为10%(w)时,可进一步改善成型纳米黏土颗粒的强度和孔结构;以成型纳米颗粒为载体负载Ziegler-Natta催化剂具有丙烯聚合活性高和立构规整控制能力强等特点,所得纳米复合聚丙烯颗粒具有良好的球形形态,且纳米颗粒在聚丙烯基体中均匀分散。     

表面改性硅灰石纤维增强油井水泥力学性能

为改善油井水泥脆性大、韧性差的缺陷并提高硅灰石纤维在水泥基材料中的作用效果,采用溶胶-凝胶法对硅灰石纤维进行纳米SiO2表面改性处理,来增强纤维与水泥基界面的结合能力.通过扫描电子显微镜(SEM)、X线光电子能谱仪(XPS)、红外光谱仪(FTIR)等测试改性硅灰石纤维的性能,结果表明:纳米SiO2成功在硅灰石纤维表面沉积且两者之间存在化学键合.将改性后的硅灰石纤维掺入水泥中测试相关性能,结果表明:改性硅灰石纤维水泥在相同养护条件下表现出优异的力学强度,养护时间14 d、掺量为7%时,改性硅灰石纤维水泥石的抗压强度和抗拉强度较空白样分别提高了35.44%和37.21%,比使用同等掺量未改性硅灰石纤维的水泥石分别提高了9.74%和9.11%,增强效果明显;改性后的硅灰石纤维降低了水泥基复合材料的孔隙率,提高了基体密实度;其在水泥中被水化产物紧密包裹,纤维与水泥石基体之间的界面结合效果更好.     

高温无机/有机复合纳米降滤失剂NFL-1研究

采用细乳化法合成的降滤失剂NFL-1是一种以无机纳米二氧化硅粒子为联接基,以-C-C-键为分子主链的两亲嵌段聚合物无机/聚合物纳米复合材料。-C-C-键分子主链上吸附基团为酰胺基(20%～30%)、主水化基团为磺酸基(40%～50%),次水化基团为羧基(10%～15%)、疏水基团为苯乙烯基(0.5%～5%)。对其在钻井液中的降滤失性能进行了评价,结果表明,NFL-1在钻井液中的黏度效应小,热稳定性好,抗盐抗钙能力强,用该降滤失剂处理的钻井液最高在220℃高温老化后其滤失量仍然较低。讨论了NFL-1的主要高温降滤失机理是纳米SiO2的高温稳定作用和NFL-1成膜阻水作用。     

纳米二氧化硅粒子对醋酸纤维素超滤膜结构的影响

以纳米二氧化硅(SiO2)为添加剂,丙酮和N,N-二甲基甲酰胺(DMF)为共溶剂,通过相转化法制备了醋酸纤维素(CA)/纳米SiO2复合超滤膜。用扫描电镜(SEM)观察了制备的CA及CA/SiO2复合超滤膜的表面结构,讨论了纳米SiO2的加入对制膜液黏度及膜孔隙率的影响。结果表明,纳米SiO2的加入可以使制膜液的黏度增大,膜孔隙率增加,同时使膜表面的微孔数增多,膜结构得到改善。     

顺丁橡胶-有机蒙脱土纳米复合材料的制备

采用溶液插层法制备了顺丁橡胶(BR)-有机蒙脱土(OMMT)纳米复合材料,采用X射线衍射仪(XRD)和透射电子显微镜(TEM)表征了BR-OMMT纳米复合材料的结构,并研究了BR-OMMT纳米复合材料的力学性能。通过100mL聚合瓶小试,考察了回收溶剂对丁二烯转化率的影响。XRD和TEM表征结果显示,OMMT片层以纳米级均匀分布在BR基体中,BR-OMMT纳米复合材料中OMMT的层间距由1.89nm增至2.52nm。与纯BR相比,当m(BR):m(OMMT)=100:6时,BR-OMMT纳米复合材料的拉伸强度提高了182%。研究结果表明,使用回收溶剂时,丁二烯的转化率大于90%。     

聚丙烯酸酯乳液改性纳米氢氧化镁/交联低密度聚乙烯复合材料的结构与性能

用纳米聚丙烯酸酯乳液改性纳米M g(OH)2,并制备了纳米M g(OH)2/交联低密度聚乙烯(XLDPE)复合材料。用FTIR,TEM,SEM等手段对纳米M g(OH)2表面性质和纳米M g(OH)2在XLDPE中的分散程度进行了表征,并对纳米M g(OH)2/XLDPE复合材料的拉伸和阻燃性能进行了研究。实验结果表明,改性的纳米M g(OH)2表面吸附了一层聚丙烯酸酯;改性纳米M g(OH)2在XLDPE基体中分散均匀;添加改性纳米M g(OH)2的复合材料的拉伸和阻燃性能明显优于添加未改性纳米M g(OH)2的复合材料;当m(改性M g(OH)2)∶m(低密度聚乙烯)=15时,复合材料的拉伸强度达到最大值(23.7M Pa)。     

PP/POE/纳米碳酸钙三元复合材料研究

以乙烯-辛烯共聚物(POE)为增韧剂,以纳米CaCO3为增强剂,将传统弹性体增韧方法与新型纳米粒子增韧增强手段相结合,利用双螺杆挤出机,通过熔融共混工艺制备出了共聚聚丙烯(PP)／POE／纳米CaCO3三元复合材料,研究了纳米CaCO3用量对复合材料的流动性和力学性能的影响,还利用扫描电子显微镜(SEM)对复合材料的断面形态进行了研究。结果表明,最佳”(纳米CaCO3)为5％左右,用少量均聚聚丙烯(PPH)代替共聚聚丙烯可改善复合材料的流动性。     

SiO2纳米粒子作润滑脂添加剂的试验研究

用Falex四球摩擦磨损试验机考察了球形和微孔型非晶SiO2纳米粒子及其与油酸复配作为润滑脂添加剂的摩擦学行为，并对其耐磨减摩作用机理进行了探讨。试验结果表明：(1)SiO2纳米粒子在润滑脂中具有较好的稳定性；(2)SiO2纳米粒子能提高润滑脂的润滑效果，减摩抗磨性能及承载能力比基础脂有较大的改善；(3)SiO2纳米粒子在添加浓度约为4％时具有最佳的效果，与油酸复配具有较好的协同效应；(4)SiO2纳米粒子的润滑作用机理是其在摩擦表面形成复合材料层。与油酸复配后在摩擦界面的吸附膜可进一步改善界面的特性。     

以丙烯酸为偶联剂制备二氧化硅／聚丙烯酸-丙烯酰胺复合材料

以丙烯酸为偶联剂,通过无皂乳液聚合方法制备了二氧化硅/聚丙烯酸-丙烯酰胺复合材料。先用丙烯酸通过stobe改进法对SiO2纳米粒子表面进行处理,得到表面接枝一层丙烯酸的SiO2粒子;然后通过与丙烯酰胺单体聚合得到二氧化硅/聚丙烯酸-丙烯酰胺核壳纳米复合材料。采用红外光谱和热重分析法对产物进行了表征。     

汽车内饰件用低VOC聚丙烯复合材料的制备及性能研究

以加氢法生产的聚丙烯（PP）为基础树脂原料,制备了具有低VOC、高耐热、高流动性、高模量等综合性能优异的PP复合材料。考察了加氢法PP及含量对复合材料综合性能的影响,确定了PP复合材料中各组分的含量：PP 60%～80%,增强填充剂10%～25%,增韧剂10%～15%,抗氧剂0.2%～0.5%,光稳定剂0.1%～0.5%。     

预处理HNTs填充PP复合材料的摩擦性能研究

The polypropylene(PP) nanocomposites filled with pretreated halloysite nanotubes(HNTs) were prepared by the melt-blending method. Before filling, the as-received HNTs powder was at first purified and then modified. The characterization tests showed that the purified HNTs had less impurity and more uniform pore size distribution and the surface hydrophobicity of the modified HNTs was obviously improved. The mechanical and tribological properties of the PP/HNTs nanocomposites were extensively investigated. The results showed that the tensile, bending and notched impact strength of the PP/HNTs nanocomposites was somewhat improved, but the wear resistance of the PP/HNTs nanocomposites was obviously enhanced.     

超细硅灰石填充PP-EPDM复合材料的研究

探讨了超细硅灰石增韧、增强的机理,研究了超细硅灰石用量对PP－EPDM体系力学性能的影响。结果表明：在一定量的EPDM存在下,随着超细硅灰石含量的增大,体系的冲击强度提高,具有增韧、增强的双重效果,将硅灰石粉表面用适当的偶联剂处理后,体系的冲击强度还可以进一步提高;随着超细硅灰石用量的增大,体系的拉伸强度、耐热性能和加工性能都稍有下降。     

Graphene-intercalated HNTs for Reinforcing PTFE

The preparation of graphene(GN) and graphene-intercalated halloysite nanotubes(HNTs) to form nanomaterials was achieved by using HNTs template. As a promising application, a series of the polytetrafluoroethylene(PTFE) nanocomposite filled with GN and GN/HNTs at different mass fractions were prepared. The mechanical and friction properties of PTFE nanocomposites depending on the mass fraction of graphene-intercalated HNTs(GN/HNTs) were intensively investigated. The comparison between the effects of GN and GN/HNTs serving as fillers on properties of PTFE was presented. The results showed that in terms of enhancing the tensile strength of PTFE, the enhancement effect of GN is superior to GN/HNTs, and in terms of the elongation at break, the GN/HNTs filler could reserve more toughness than GN. The Young's modulus of the GN/HNTs incorporated into PTFE is about 1.9 times larger than pure PTFE, and is superior to GN/HNTs. The friction coefficient of PTFE nanocomposites filled with GN and GN/HNTs was slightly higher than pure PTFE and the latter was lower than the former. The volume wear rate of PTFE nanocomposites filled with GN/HNTs was obviously lower than the case with GN, which exhibited the better wear resistance of GN/HNTs used as filler     

纳米二氧化硅/有机硅改性水性聚氨酯的合成及包覆RDX的性能研究

以聚醚二醇、异佛尔酮二异氰酸酯、二羟甲基丙酸、三乙胺、乙二胺、三羟甲基丙烷、纳米二氧化硅、硅烷偶联剂KH550为原料,合成了纳米二氧化硅/有机硅改性水性聚氨酯,并研究了纳米SiO2用量对 WPU － Si 膜的表面性能、力学性能、热稳定性及包覆RDX颗粒效果的影响。结果表明,随着Si含量的增加,乳液的稳定性逐渐降低,熔点呈现出先降低后升高的趋势;材料的热力学稳定性增强,耐高温性增强,拉伸强度增大,但是断裂伸长率随着纳米SiO2的增加而降低。随着Si含量的增加,材料的表面张力降低,吸水率降低,接触角逐渐增大,使得聚氨酯和待包覆的RDX表面张力接近,包覆效果得到改善。     

Mechanical and physical properties of nanosilica/nitrile butadiene rubber composites cured by gamma irradiation

Nitrile Butadiene Rubber (NBR) nanocomposites are prepared with different contents ranging from 5 to 20 phr (part per hundred parts of rubber) of Sinai sand nanoparticles and fumed silica micro particles (SiO2) and mixed with other additives to improve its properties. The nanocomposites were irradiated with gamma irradiation from 25 to 150 kGy. The effect of the silica content and irradiation dose on the morphology, the mechanical and the physical properties of nanocomposites was investigated. The scanning electron microscope (SEM) showed that there is a fine dispersion of nanoparticles into NBR matrix, also some aggregates were observed and their size depends on the SiO₂ content. The results indicated that there was an improvement in tensile strength by increasing irradiation doses up to 50 kGy and by increasing silica loading up to 15 phr. Enhancement of volume fraction by increasing irradiation doses and also by increasing silica loading was observed. The thermal gravimetric analysis (TGA) indicated that the thermal stability of NBR increases by increasing silica contents and the increase in irradiated samples is higher than that in un-irradiated. Finally, it is found that the presence of silica in the nanocomposites enhances the electrical insulating properties of the NBR.     

Preparation,characterization and evaluation of polybenzoxazine thermoset/clay nanocomposites for metal coating

A series of polybenzoxazine-clay nanocomposites with various organoclay contents (3, 5, 10, and 20 wt%) were prepared by the one-shot procedure. from organo-montmorillonite (OMMT) and bifunctional benzoxazine, namely, bis-(3-dodecyel-3,4-dihydro-2H-1,3-benzoxazine) isopropane (B-dod). OMMTs were prepared by modification of Na-MMT with different ammonium salts of amines such as tyramine (Tyr), amino lauric acid (ALA) and N,N-dimethyl stearyl amine (DMS). Transmission electron microscope (TEM), X-ray diffraction (XRD) and infrared measurements (FTIR) were used to examine the structure and modification of OMMTs. The morphology of polybenzoxazine nanocomposites (B-dod/Tyr-MMT, B-dod/ALA-MMT, B-dod/DMS-MMT) was investigated by X-ray and TEM analyses. The X-ray analysis and TEM photos indicated that organoclay was exfoliated into polybenzoxazine matrix even at the highest organoclay loading (20%). Mechanical properties (viz, adhesion on metallic substrate, scratch hardness, tensile modulus, and elongation at break) of the prepared nanocomposites were measured. The tensile properties of prepared samples were examined; as the content of modified clay was increased, the tensile modulus increased; however, the elongation at break decreased. In addition, the optimum adhesion and scratch hardness values of the prepared nanocomposites were increased more than the neat resin, also, thermogravimetric analysis has the same manner. Therefore, the prepared nanocomposite materials could be successfully used for metal coatings.     

纳米SiO_2溶胶缓解油井水泥高温强度衰退的作用机理

油井水泥石强度衰退是高温固井所面临的主要难题之一,而添加纳米SiO_2能否缓解水泥石的高温强度衰退以及其作用机理是什么,还有待于验证和确认。为此,通过室内试验,基于X射线衍射仪、扫描电子显微镜和能谱仪分析水泥石的矿物组成、微观结构和水化产物的元素,测定了高温条件下(150℃/35 MPa)纳米SiO_2溶胶对G级油井水泥石抗压强度的影响及变化规律,据此研究纳米SiO_2溶胶在高温下对水泥水化产物的作用机理。研究结果表明:①纳米SiO_2溶胶可以提高G级油井水泥浆的稠度系数,对水泥浆的流变性会产生不利的影响;②在高温养护初期,纳米SiO_2溶胶会降低水泥石的抗压强度,但加入纳米SiO_2溶胶的水泥石的抗压强度不会随着养护时间的增加而产生明显的变化;③加入少量纳米SiO_2溶胶的G级油井水泥中的纳米SiO_2颗粒吸附在水泥矿物表面阻碍水化反应,能够缓解水泥水化产物的高温脱水变质,纳米SiO_2颗粒还可以提高水泥微观结构的致密性;④加入大量纳米SiO_2溶胶的G级油井水泥中的纳米SiO_2与氢氧化钙发生火山灰反应生成一种新型的、结构松散的薄片蜂窝状CSH产物,难以提供较高的抗压强度。结论认为,纳米SiO_2可以作为水泥添加剂以缓解油井水泥高温强度衰退,该研究成果为高温固井水泥浆体系的设计提供了一条新的思路。     

Electrophysical characteristics of polyurethane/organo-bentonite nanocomposites

Modification of the Egyptian Bentonite (EB) was carried out using organo-modifier namely; octadecylamine ODA. Before the modification, the cation exchange capacity (CEC) of the EB was measured, also it was purified from different impurities using HCl and distilled water. The Organo-bentonite OB was characterized using IR, XRD, and TEM. PU/ODA-B nanocomposites were prepared by in situ polymerization then characterized by XRD and TEM. An amount of ODA-B ranging from 0.25% up to 5% by weight was added to the polyol component of the resin before mixing with toluene diisocynate TDI. TEM showed that the nanocomposites achieved good dispersion in the polyurethane matrix. The mechanical, swelling and electrical properties of the nanocomposites were measured. The results indicate that the tensile strength of all the nanocomposites enhanced with the addition of OB compared with the pure PU. The crosslink density of the nanocomposites increases with increasing the content of OB. The Pool–Frenckel conduction mechanism predominates for all the nanocomposite samples and the blank one.