改性绢云母对顺丁橡胶导热性能的影响

采用硬脂酸对绢云母进行表面改性,研究改性绢云母用量对绢云母/顺丁橡胶复合材料性能的影响.结果表明,随着改性绢云母用量的增大,复合材料的硫化速度加快,转矩和门尼粘度增大,加工性能下降;邵尔A型硬度、热导率和介电常数逐渐增大,拉伸强度、拉断伸长率、拉断永久变形、撕裂强度、表面电阻率和体积电阻率均先增大后减小,而击穿电压变化不大.     

聚丙烯/马来酸酐接枝聚丙烯/超细云母的界面增容及其断面形态研究

:针对 PP/云母相界面缺乏亲和力 ,云母对 PP力学性能改善不明显的缺陷 ,采用偶联剂KH- 570与 PP- g- MAH并用的技术对超细云母进行表面处理并与 PP共混增容。结果表明 ,云母能同时有效提高 PP的强度、模量、硬度和冲击强度。其中 ,由于 PP- g- MAH导致的界面强度提高和界面层厚度增加 ,使 KH- 570与 PP- g- MAH并用的 PP/PP- g- MAH/云母 - 4#材料比单用 KH- 570的PP/云母 - 4# 材料的改性效果更加明显。同时发现 ,云母对 PP的结晶过程具有较明显的成核作用 ,使改性 PP的结晶温度和熔融温度提高     

纳米云母改性聚丙烯复合材料的制备及性能研究

以聚丙烯(PP)为基体及纳米云母为改性剂,用混炼法制备纳米云母/聚丙烯复合材料。对未改性的纳米云母、烷基改性的纳米云母及甲基丙烯改性的纳米云母与聚丙烯的复合材料的力学性能和热性能进行比较分析。结果表明,经傅里叶变换红外光谱(FTIR)分析,证实纳米云母已成功改性,由扫描电子显微镜(SEM)分析,云母粉末为纳米级,改性影响了聚丙烯和云母之间的结合性,与未改性的云母相比,改性云母的各项性能较好。通过X射线衍射(XRD)分析,纳米云母不会影响聚丙烯的结晶行为和收缩关系。在力学性能方面,纳米云母(1 phr)虽然可以增加拉伸强度,但随着纳米云母的添加增加至7phr,复合材料变硬变脆而下降,拉伸强度略微下降,冲击强度显著下降,而拉伸模量和表面硬度都提高10%以上,表明改性后的纳米云母与聚丙烯融合性更强。在热性能方面,在7 phr纳米云母添加量下,其维卡软化温度提高约10%,表明添加烷基改性比甲基丙烯改性云母的复合材料稳定性更好;随着云母添加量增加,耐热性提升效果明显,但因改性剂会先裂解,导致改性的纳米云母降低了纳米复合材料的耐热性。     

竹片/环氧乙烯基酯树脂复合材料的界面性能研究

采用不同浓度的碱与不同浓度的硅烷偶联剂对竹片进行表面改性,研究了表面改性对竹片抗拉强度及其复合材料制品界面层间剪切强度的影响。实验结果表明:适当浓度的碱处理改性方法对竹片拉伸强度和竹复合材料界面剪切强度的提高要明显优于KH550改性方法,双重改性对竹片的抗拉强度具有较好的改善效果;通过扫描电镜分析冲击断面破坏方式发现,竹片/环氧乙烯基酯树脂复合材料界面损伤模式主要表现为竹片中竹纤维抽拔断裂、基体断裂、纤维/基体界面脱粘以及剪切分层,界面性能有所改善。     

硅烷偶联剂改性绢云母补强丁苯橡胶的研究

以片状绢云母粉体为基料,采用γ-巯丙基三乙氧基硅烷对绢云母表面改性,通过橡胶复合材料的力学性能评价表面改性效果。结果表明：改性剂用量2%、改性温度90℃、改性时间20 min为绢云母粉体最适宜的改性条件,此条件制备的绢云母/丁苯橡胶( SBR)复合材料力学性能改善明显。 FTIR分析表明：硅烷偶联剂与矿物表面发生了化学键合;SEM观察发现改性绢云母能均匀分散在橡胶基体中,与橡胶形成良好界面结合,证实了绢云母通过表面改性能有效的提高对丁苯橡胶的补强性能。     

低温氨气等离子体对芳纶表面的改性

采用氨气等离子体对芳纶表面进行改性,用X-射线光电子能谱、场发射扫描电子显微镜、力学性能测试等手段对改性前后纤维表面的元素组成、形貌及其拉伸强度进行表征,并进一步通过微脱黏方法分析了等离子体处理条件对芳纶/环氧树脂复合材料界面黏结强度的影响。结果表明:芳纶经表面改性后,其表面极性官能团、表面粗糙度均有所增加,同时与环氧树脂基体的界面黏结强度明显增加。     

木粉的表面改性及其对聚丙烯/木粉复合材料力学性能的影响

改善填料与聚合物基体之间的界面相互作用是提高聚合物复合材料力学性能的关键所在。分别用碱(氢氧化钠)、酸(乙酸酐)、聚多巴胺对木粉(WF)进行表面改性,然后将改性后的WF与聚丙烯(PP)通过熔融共混制得PP/WF复合材料。采用傅里叶变换红外光谱仪、热重分析仪、扫描电子显微镜等手段对WF及复合材料的形态结构进行了表征,并分析了WF的表面改性对复合材料性能的影响。结果表明,这三种表面改性均可有效改善WF与PP的界面相互作用,从而使复合材料的力学强度得到明显提升。其中,聚多巴胺处理对界面强度和力学强度的改善效果最为明显,并且还可使基体的冲击韧性得到保持。当经多巴胺处理的WF的质量分数为50%时,PP/WF复合材料的拉伸强度和弯曲强度分别可达64.87、67.96MPa,相对于原始WF填充的复合材料分别增加了37.8%、39.9%。     

环氧树脂/多巴胺增强芳纶纤维界面性能

由于芳纶纤维表面光滑且呈现化学惰性,与环氧树脂等基体材料结合后界面性能较差。为此,采用多巴胺在不同时间下对改进型芳纶Ⅲ纤维表面进行改性处理,并研究了对环氧树脂/多巴胺改性芳纶纤维界面性能的影响。对扫描电子显微镜对纤维改性前后表面形貌进行表征,发现纤维改性后表面粗糙度提高,利于与环氧树脂间界面结合。利用傅里叶变换红外光谱、X射线光电子能谱对纤维改性前后基团和表面元素含量进行表征,改性后纤维表面活性基团增加,极性增强。通过热重分析表明聚多巴胺成功吸附在纤维表面。测量纤维表面接触角,改性后的接触角更小,有利于环氧树脂润湿纤维。采用横向丝束复合材料的拉伸强度表征环氧树脂/芳纶纤维的界面性能。最终确定了多巴胺浓度为2 g/L,在多巴胺溶液中处理4 h为最佳条件,在该条件拉伸强度比为改性前提高了28.06%,拉伸弹性模量提高了14.68%。     

果壳粉和木粉的制备与表面处理方法的研究

以果壳和木屑为原材料,制备成不同目数果壳粉和木粉,并分别对果壳粉和木粉表面进行改性。本实验采用表面接枝马来酸酐(MAH)的果壳粉和木粉处理方法,将MAH改性后的木粉和果壳粉填加到PVC树脂基体中,通过改变MAH的用量,比较了果壳粉和木粉/PVC复合材料拉伸,抗弯性能的变化情况。复合材料的抗弯强度和拉伸强度明显提高,果壳粉和木粉填充复合材料的弯曲强度分别达到68.12 MPa和80.05 MPa,达到最大值。果壳粉与PVC的界面连接得到改善。实验结果表明:改性后的果壳粉/复合材料的拉伸性能和抗弯性能明显提高。     

改性T-ZnOw掺杂NR垫板的性能

研究改性前后四针状氧化锌晶须(T-ZnOw)对NR减震橡胶垫板拉伸强度、拉断伸长率和耐磨性能的影响,并采用扫描电子显微镜观察NR垫板磨耗后的表面形貌.结果表明,经硅烷偶联剂表面改性的T-ZnOw用量分别为5和2.5～3份时,NR垫板试样的拉伸性能和耐磨性能分别较优;改性T-ZnOw与NR基体间存在着较好的界面结合,改性T-ZnOw对提高橡胶材料的耐磨性能有更好的效果.     

Preparation and characterization of ethylene-butene copolymer (EBC)/mica composites

Composites of ethylene-butene copolymer (EBC) with various amounts of untreated mica and silane modified mica were prepared by the melt blending technology. The morphological, thermal, dielectric and mechanical properties of composites were investigated. The results showed that both of raw mica and treated mica were uniformly dispersed in the polymer matrix. Attributed to the heterogeneous nucleating effect of mica, the crystallization ability of composites was increased and the crystals of the polymer matrix were arranged more closely. With increasing the filler content, the thermal stabilities of composites were improved, whose increasing rate was decreased when the filler content was up to a certain amount. The dielectric properties of samples were influenced by the filler content, surface treatment of mica and the testing frequency. The mechanical properties showed that the tensile strength and elongation at break of composites were not decreased apparently until the filler content was up to 30 wt%. And the hardness and modulus at 100% elongation of samples were increased with the increase in the filler content, ascribed to the reinforcing effect of mica.     

PP/云母复合材料的增容效果及其界面结构

制备和研究了８０目、４００目和１２５０目三种不同粒径的云母增强ＰＰ复合材料。结果显示,云母可普遍提高ＰＰ的强度、模量和室温韧性,其中弯曲性能增幅尤甚,但材料断裂伸长率下降。减小云母粒径,材料韧性上升而刚性下降。ＰＰ－ｇ－ＭＡＨ可强化ＰＰ与云母两相的界面结合,使界面过渡层变厚,从而普遍提高各项性能。     

Morphologies,Mechanical Properties and Wear of Poly(ether ketone ketone) (PEKK) and its Composites Reinforced with Mica

Poly(ether ketone ketone) (PEKK) composites were developed using mica as a filler. Sulfonated poly(ether ketone ketone) (S‐PEKK), a possible interfacial modifier, was coated on the mica surface with ca. 50 nm thickness, as observed by contact atomic force microscope (AFM). The morphologies of these materials were examined by scanning electron microscopy (SEM). In comparison with PEKK, significantly improved mechanical properties were obtained for the composite materials. With increasing content of mica in the materials, tensile modulus of the materials increased and ultimate elongation decreased. The composites containing 30 wt.‐% of mica exhibited a maximum tensile strength of about 200 MPa while pure PEKK showed a tensile strength of 102 MPa. The composites filled with mica treated by S‐PEKK displayed somewhat higher values of tensile strength and ultimate elongation than those generated using pure mica. The glass transition behavior and thermal stability of PEKK were not affected by the composition of the materials. The amount of mica used in the composites showed some influence on the coefficient of friction and wearing rate of these materials.     

Effect of coupling agents on the mechanical properties of mica/epoxy and glass fiber/mica/epoxy composites

The effect of coupling agents, two silane and one zirconate, on the mechanical properties of mica/epoxy and glass fiber/mica/epoxy composites has been investigated. The results showed that tensile modulus and flexural strength and modulus values were improved by the surface treatment of the coupling agents. The property retention was also found to be better in the case of coupling agent-treated mica/epoxy samples after boiling in water for 2h. In the case of glass fiber/mica/epoxy composites, the flexural modulus and interlaminar shear strength values improved with increase in mica content, but the effect of coupling agents was not pronounced.     

Influence of Fiber Surface Modification on the Mechanical Performance of Isora-Polyester Composites

This paper reports the effect of chemical treatment on the mechanical properties of a natural fiber, isora, as reinforcement in unsaturated polyester resin. Isora fiber is separated from the bark of the Helicteres isora plant by a retting process. The short isora fiber surface was modified chemically by acetylation, benzoylation, silane and triton treatments to bring about improved interfacial interaction between the fiber and the polyester matrix. The modified surfaces were characterized by IR spectroscopy and SEM. The SEM studies were carried out to investigate the fiber surface morphology, fiber pull-out and fiber-polyester interface bonding. They showed the changes occuring on the fiber surface during chemical treatment. Properties like tensile strength, flexural strength and impact strength have been studied. The chemical modification of fiber improved fiber/matrix interaction as evidenced by the enhanced tensile and flexural properties. The lower impact properties of the composites, except triton-treated fiber composite, further point to the improved fiber/matrix adhesion, compared to the untreated fiber composites.     

Performance of hybrid reinforcements in PVC composites. II: Use of surface-modified mica and different cellulosic materials as reinforcements

The effect of the composition of various wood fibers and surface-treated mica as well as different surface treatments of cellulosic materials on the mechanical properties of PVC composites has been evaluated. Cellulosics were surface modified by prior coating with maleic andydride (MA), mixtures of MA and Na-silicate and isocyanate. The filler concentration was fixed at 25 wt%. Both tensile strength and modulus of composities filled solely with mica are superior to those of non-treated wood fiber-filled composities. while the reverse is true for impact strength (except for bagasse-filled composities), ultimate elongation, and tensile toughness. Moreover, the mechanical properties of composities, with the exception of modulus, filled only with mica and/or non-treated wood fibers are inferior to those of unfilled PVC. Compared to non-treated fiber-filled composites, properties improved when surface-modified wood fibers were used alone, or along with mica. Isocyanate-coated wood fibers ranked best with regard to the mechanical properties of the composities. Properties also changed with the change of wood species and compositions of mica and wood fibers. Experimental results indicate good compatibility between surface-treated wood fibers/mica and PVC composities.     

Synthesis,characterisation and enhanced properties of polyimide/mica hybrid films

Polyimide/mica (PI/mica) hybrid films were prepared from pyromellitic dianhydride/4,4-bis(3-aminophenoxy)biphenyl (PMDA/4,3-BAPOBP) and mica in a solution of N,N-dimethylacetamide. The structure–property relationships of the composites were studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible spectroscopy and differential scanning calorimetry. FTIR indicated successful preparation of PI/mica hybrid films. XRD and SEM results indicated that the mica was well dispersed in the PI matrix. The dependence of morphology, glass transition temperatures (T_g), dielectric properties and mechanical properties at room temperature of the hybrid films on the content of mica was discussed. It was observed that T_g, the breakdown strength and tensile strength of the hybrid films, could be simultaneously increased when the mica content was lower than 8?wt-%. Meanwhile, the dielectric constant and dielectric loss of PI/mica hybrid films increased with the increase in the mica content.     

汽车活塞销镀Ni-Co合金镀层表面改性及性能研究

利用电镀技术,在汽车活塞销表面制备Ni-Co合金镀层实现表面改性。概述了活塞销表面改性的工艺过程,观察了表面改性后活塞销的形貌,检测了Ni-Co合金镀层与活塞销基体的结合强度以及表面改性后活塞销的硬度、抗拉强度及耐摩擦磨损性能。结果表明,Ni-Co合金镀层与活塞销基体结合牢固,表面改性后活塞销的表面平整均匀,硬度和抗拉强度均提高,表现出较好的耐摩擦磨损性能。Ni-Co合金镀层有效改善了活塞销的表面状况,使活塞销的硬度提高约17%,抗拉强度提高约7.2%,磨损量和磨损速率分别下降17.5%和17.9%。     

Fabrication and Characterization of Electrospun PVA/Mica Fibrous Nanocomposite Mats

This paper focuses on the fabrication of cost effective and high performance poly(vinyl alcohol)/mica fibrous nanocomposites using electrospinning. Effective incorporation of fine particles of mica in poly(vinyl alcohol)/mica nanocomposites was examined and confirmed along with the evidence of good dispersion, by digital optical microscopy and scanning electron microscopy. The presence of mica improved the mechanical properties of the nanocomposites without affecting the thermal stability. The electrospun poly(vinyl alcohol) mats containing 20?wt% mica exhibited tensile strength of 13.29?MPa and tensile modulus of 180.3?MPa as compared to values of 3.92 and 83?MPa, respectively, for poly(vinyl alcohol) fiber mats.     

云母粉改性高密度聚乙烯的汽油阻隔性

以片状云母粉为阻隔改性剂,与高密度聚乙烯(PE–HD)熔融共混,以改善其对汽油的阻隔性,考察云母粉形貌、含量等因素对PE–HD/云母粉复合材料阻隔性、熔体流动性以及力学性能的影响。结果表明,云母粉可显著提高复合材料对汽油的阻隔性,但熔体流动速率(MFR)与断裂伸长率降幅明显,高径厚比的云母粉对复合材料的汽油阻隔性提升更为显著,但径厚比过大不利于阻隔性的进一步提升,并会导致材料MFR和断裂伸长率进一步下降;当云母粉含量开始增加时,复合材料的汽油阻隔性明显提升,拉伸强度与缺口冲击强度上升,而MFR和断裂伸长率下降,当裂纹发展方向垂直于云母片面积方向时,缺口冲击强度提高更为显著;随着云母粉含量继续增加,复合材料的汽油阻隔性趋于稳定,拉伸强度与缺口冲击强度却明显下降。当径厚比为180的云母粉质量分数为30%时,复合材料具有最佳的综合性能,其汽油浸泡后的拉伸强度保持率显著高于纯PE–HD。