聚丙烯/蒙脱土纳米复合材料流变性能及抗紫外性能的研究

采用毛细管流变仪和熔融指数测定仪对聚丙烯/蒙脱土纳米复合材料的流变性能进行了研究,讨论了复合材料的熔融指数、非牛顿指数、表观粘度及粘流活化能与组成之间的关系。考察了复合材料的抗紫外性能。结果表明:复合材料流体为假塑性流体,其表观粘度对剪切速率的依赖性随纳米蒙脱土质量分数的增大而变小;复合材料的表观粘度随纳米蒙脱土质量分数的增加而逐渐增大,纳米蒙脱土的加入对体系流动有一定的阻碍作用;随着纳米蒙脱土质量分数的增大,复合材料对紫外光的屏幕效果越来越强。     

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(Polyprpropylcnc／Mommorillonite Nanocomposites．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／m^2。和35．77MPa，分别比纯PP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。     

聚丙烯腈／蒙脱土纳米复合材料的制备

采 用微波交 换法分 两步将浮 选后的 天然 钙基 蒙脱 土转 变为 镍基 蒙脱 土, 通过 丙烯腈 单体与镍 基蒙脱 土层间镍 离子的 络合作 用,把 丙烯 腈单 体引 入蒙 脱土 层间 ,然 后用 过硫酸 铵引发丙 烯腈原位 聚合制 备聚丙烯 腈／ 蒙脱 土纳米 复合 物．由 Ｘ 射 线荧 光分 析测 定钙基蒙 脱土和镍 基蒙脱土 的化学 组成,求 得镍离子 交换 度为 ９１ ．４ ％ ． Ｘ 射 线粉 末衍 射结 果显示,聚 丙烯腈／ 蒙 脱土复 合物试 样的（ ００１） 衍 射峰（ ２ θ） 由镍 基 蒙脱 土的 ５ ．６°移 至低 于 ２°的位置 ,即 ｄ（００１ ） 值由 １ ．５８ ｎ ｍ 增至４ ．４１ ｎ ｍ 以上 ．复合物 试样的红 外光谱 中未 见 Ｃ＝ Ｃ 双键吸 收峰,说 明聚合反 应已进 行完全．透 射电镜 照片 显示 蒙脱 土的 硅酸 盐片 层 以单 层无 规则分 散在聚合 物基体 中．     

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。     

聚丙烯/PP-g-MA/蒙脱土纳米复合材料的制备和性能研究

采用聚丙烯接枝马来酸酐（PP-g-MA）作增容剂改性聚丙烯（PP）/蒙脱土（MMT）纳米复合材料,研究了不同PP-g-MA含量对PP/PP-g-MA/MMT的流动性、拉伸强度、冲击强度、耐热性、晶体形貌以及MMT分散的影响。结果表明：当PP-g-MA的质量分数为5%时,PP基体的晶粒细化,MMT分散得以改善,拉伸强度基本不变,冲击强度却大幅度增加。     

蒙脱土/SBS纳米复合材料研究

介绍了蒙脱土/SBS纳米复合材料的研究现状,简述了蒙脱土的结构特征和表面有机修饰,探讨了蒙脱土/SBS纳米复合材料的制备方法,即熔融插层法和溶液插层法等,并指出了进一步研究的方向.     

蒙脱土／聚丙烯酰胺复合材料的制备和性能研究

以阳离子交换树脂为载体，钙基蒙脱土经微波加热离子交换制备镍蒙脱土，Ｎｉ＾２＋交换程度达到９１．４％，丙烯酰胺经络合引入蒙脱土层间聚合为复合材料，使层间距增至２ｎｍ左右，同时考察了调湿性能与原料配比的关系。     

橡胶/有机蒙脱土纳米复合材料的研究进展

介绍了蒙脱土的结构及有机化改性的方法,橡胶／有机蒙脱土纳米复合材料的制备原理和方法。同时,介绍了纳米复合材料的结构表征手段,然后对该复合材料的国内外研究现状作了综述,并对其进一步应用作了展望。     

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.     

Effect of different montmorillonites on rheological properties of bitumen/clay nanocomposites

Different composites of organomodified montmorillonite(OMMT)/bitumen were prepared by melt blending with hexadecyl dimethyl benzyl ammonium modified montmorillonite(HBM) and double octadecyl dimethyl ammonium modified montmorillonite(DOM).The structures of two kinds of montmorillonite modified bitumen were characterized by X-ray diffraction(XRD).The effects of different montmorillonites on the dynamic rheological properties of the modified bitumens were investigated by dynamic shear rheometer(DSR).The XRD results show that DOM modified bitumen forms an intercalated structure,whereas the HBM modified bitumen forms an exfoliated structure.DSR results indicate that OMMT modified bitumens exhibit higher complex modulus,lower phase angle than pristine bitumen,which means that the resistance to rutting at high temperatures of pristine bitumen is improved due to the introduction of OMMT.Compared with DOM modified bitumen,HBM modified bitumen shows better rutting resistance,which is contributed to the formation of exfoliated structure in HBM modified bitumen.     

四官能基环氧树脂／蒙脱土纳米复合材料的制备及表征

采用阳离子交换的方法对蒙脱土进行了有机化改性,并制备了环氧树脂／蒙脱土纳米复合材料．用FT-IR和XRD研究了环氧树脂／蒙脱土纳米复合材料的结构,并测试了纳米复合材料的性能．实验结果表明,改性使蒙脱土层间距变大,纳米复合材料的力学性能与纯环氧树脂相比提高了50％．     

超支化聚酯改性聚丙烯流变性的研究

将超支化聚酯应用于聚丙烯纤维的共混改性,研究了超支化聚酯对聚丙烯流变性能的影响。实验结果表明,共混体系为非牛顿假塑性流体,其表观黏度随切速率的增大而减小,随温度升高而降低,随着超支化聚酯质量分数增加而减小。共混体系的非牛顿指数随超支化聚酯质量分数增加而降低,流变性能得到改善。当超支化聚酯为6%时,体系黏流活化能为45.34 kJ/mol。     

EVA改性丙纶的流变性能

报道了用EVA对丙纶物理改性的实验研究，论述了这种改性丙纶的流变性能。由于引入极性基团，破坏了丙纶的高规整性导致的高度结晶，并且通过部分溶出改性剂生成微孔，从而大大改善了丙纶纤维的吸湿性能和导电性能。共混体系的粘度对温度和压力都有明显的依赖性，改性剂EVA的加入量不同影响了共混体系的粘度，在纺丝过程中值得注意。     

EVA改性丙纶的流变性能

报道了用EVA对丙纶物理改性的实验研究,论述了这种改性丙纶的流变性能。由于引入极性基团,破坏了丙纶的高规整性导致的高度结晶,并且通过部分溶出改性剂生成微孔,从而大大改善了丙纶纤维的吸湿性能和导电性能。共混体系的粘度对温度和压力都有明显的依赖性,改性剂EVA的加入量不同影响了共混体系的粘度,在纺丝过程中值得注意。     

Rheological behavior of novel polyamide 6/silica nanocomposites containing epoxy resins

A novel polyamide 6/silica nanocomposite containing epoxy resins(EPA6N) was prepared via in situ polymerization using tetraethoxysilane(TEOS) as the precursor of silica.The dynamic rheological properties of pure PA6 and EPA6N at temperatures of 225 and 235 ℃ were investigated.The results of transmission electron microscopy(TEM) and atomic force microscopy(AFM) indicate that the silica particles are well dispersed in the polyamide 6 matrix on about 30 nm in diameter,which demonstrates that this method can effectively avoid agglomeration of the inorganic particles.The rheological results suggest that pure PA6 shows Newtonian behavior.However,the novel EPA6N exhibits a solid-like rheological behavior,which is due to the small size,large surface of silica particles and the stronger polyamide 6-silica chemical bond formed through the reactions of epoxy resins with end groups of PA6 molecular chains.The EPA6N also exhibits higher melt viscosity,storage modulus and loss modulus than those of pure PA6.     

Preparation and characterization of polylactide/montmorillonite nanocomposites

The montmorillonite, a form of layered silicate, was successfully intercalated into polylactide (PLA) matrix through solvent-casting technique. In addition, PLA/MMT nanocomposite films were produced, in which homogenous distribution of the silicate lamellae plays a key role in the mechanical properties of the films. A small amount(5wt%) of OMMT intercalated into the PLA matrix resulted in their flexibility enhancement, from 3.68%(pure PLA film) to 352.65%. The results of wide-angle X-ray diffraction (WAXD) patterns confirmed that the silicate interlayer distance increased from 3.044 nm (for OMMT) to 3.56nm (for 5wt%, maximum) with increasing OMMT contents, but decreased to 3.319 nm when OMMT content was over 8wt%. FT-IR also verified the molecular-level associations between PLA chains and OMMT lamellae by vibration variances of hydrogen bonding. DSC thermograms demonstrated that thermal stabilities of the nanocomposite films enhanced, due to the silicate lamellae dispersed into PLA matrix.     

Effects of thermal-oxidative aging on rheological properties of montmorillonite modified bitumen

Organic montmorillonite(OMMT) modified bitumen nanocomposites was prepared by melt blending.The effects of thin-film oven test(TFOT) and pressure ageing vessel(PAV) on rheological properties of pristine bitumen and OMMT modified bitumen were investigated by dynamic shear rheometer(DSR).The results show that complex modulus(G*) increases,phase angle(δ) decreases and rutting factor(G*/sin δ) is enhanced for the pristine bitumen after TFOT,whereas G*,δ and G*/sin δ of OMMT modified bitumen have a little change before and after TFOT.Besides,the pristine bitumen exhibits a large increase of G* and a great decrease of δ after PAV aging.However,the changes in G* and δ of OMMT modified bitumen are small before and after PAV.Compared with the pristine bitumen,OMMT modified bitumen presents a lower fatigue factor(G*sin δ) after PAV.As a consequence,resistance to thermal-oxidative aging of bitumen is remarkably improved due to the introduction of OMMT.