Adhesive properties of polypropylene (PP) and polyethylene terephthalate (PET) film surfaces treated by DC glow discharge plasma

In this study, the adhesive properties of the plasma modified polypropylene (PP) and polyethylene terephthalate (PET) film surfaces have been investigated. Hydrophilicity of these polymer film surfaces was studied by contact angle measurements. The surface energy of the polymer films was calculated from contact angle data using Fowkes method. The chemical composition of the polymer films was analyzed by X-ray photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) was used to study the changes in surface feature of the polymer surfaces due to plasma treatment. The adhesion strength of the plasma modified film was studied by T-peel strength test. The results showed a considerable improvement in surface wettability even for short exposure times. The AFM and XPS analyses showed changes in surface topography and formation of polar groups on the plasma modified PP and PET surfaces. These changes enhanced the adhesive properties of polymer film surfaces.     

电感耦合等离子体对HDPE粉体的表面处理

用搅拌式电感耦合等离子体反应器对高密度聚乙烯（HDPE）粉体进行表面处理,采用水接触角、红外光谱（FT-IR）和X射线光电子能谱（XPS）对等离子体处理前后HDPE粉体的水接触角、表面成分的变化进行分析。实验结果表明,随着等离子体处理时间延长和放电功率增加,水接触角减小。在功率100W处理30min后,水接触角从处理前...     

氩气低温等离子体处理HDPE薄膜表面的性能研究

利用低温等离子体,以氩气为工作气体,在工作压强为20Pa、处理功率为30W的条件下对HDPE薄膜进行了表面改性。用接触角、SEM、AFM、XPS等手段对改性结果进行了分析和表征。研究结果表明:在0～300s的处理时间内,失重率在处理时间为90s左右时达最大值;接触角在0～160s内随处理时间的增加显著减小,而在160～300s的处理时间内没有发生明显变化;改性后的接触角随着放置时间的推移出现微弱回复;HDPE薄膜经过氩气低温等离子体处理后,能在其表面形成各种极性基团,主要是羰基、羟基和羧基,且薄膜经处理后,其表面的结合能及平面光洁度发生了改变。     

Investigation of long-term hydrophobic recovery of plasma modified polypropylene

This study concerns the surface and adhesive properties of isotactic polypropylene (iPP) modified by an electric discharge plasma and affected by long-term hydrophobic recovery of the polymer surface after modification. The investigations were focused on the change in polarity of the modified polymer expressed by the polar fraction as well as on the decrease in the surface free energy, its polar component and mechanical work of adhesion (A _m) to polyvinyl acetate. A _m of modified iPP to polyvinyl acetate as a function of polar fraction can be described by a mathematical formula. It has been confirmed that the most intensive decrease in the surface and adhesive properties investigated is produced by the long-term hydrophobic recovery of the polymer appears in the course of the first 30 days after its modification. During subsequent aging the process of polymer hydrophobic recovery proceeds more slowly. It has been found that the value of surface and adhesive properties of iPP as well as the dynamics of the decrease in these properties during hydrophobic recovery of the surface after modification is, in the main, dependent on the iPP crystallinity.     

剑麻纤维表面特性及其浸润行为

采用Weibull统计分布方法量化了剑麻纤维的横截面积, 并考虑液体在剑麻纤维中空结构中的芯吸质量, 发展了基于Wilhelmy吊片法原理测试剑麻纤维与液体动态接触角的表征方法。在此基础上, 分析了不同表面处理方法对剑麻纤维微观结构、 表面化学组成、 表面能及其色散、 极性特性的影响规律, 并测试了剑麻纤维与E51环氧树脂的浸润性。结果表明: NaOH、 阻燃剂处理使剑麻纤维表面极性官能团增加, 纤维的表面能极性分量增加显著; 硅烷处理增加了剑麻纤维表面的极性基团含量, 但使其极性分量减小, 表面能略有下降; 并且剑麻纤维与E51树脂的浸润性与其极性比匹配特性密切相关。     

毛白杨木粉/聚丙烯复合材料界面相容性的介电弛豫解析

为解析木塑复合材料的界面相容性机制,通过介电弛豫过程分析研究不同硅烷偶联剂添加量的毛白杨木粉/聚丙烯复合材料的温度谱及频率谱,并计算介电弛豫过程中的表观活化能和热力学量。结果表明:在添加硅烷偶联剂的毛白杨木粉/聚丙烯复合材料中能观察到基于木材细胞壁无定形区中伯醇羟基的回转取向运动的弛豫过程;弛豫强度随硅烷偶联剂添加量增大先减少而后缓慢增大;随偶联剂添加量的增大,弛豫时间分布峰呈先变宽、变低,然后再变尖、变高趋势;表观活化能、活化焓、活化自由能和活化熵随硅烷偶联剂添加量增加先增大后减小。表观活化能在硅烷偶联剂添加量(质量比)为2.0%时达到最大值(28.12kJ/mol),与未添加偶联剂的毛白杨木粉/聚丙烯复合材料的(13.86kJ/mol)相比增加2倍以上,活化焓在硅烷偶联剂添加量从0%时的12.09kJ/mol增大到2.0%时的26.35kJ/mol,增大了117.9%,说明弛豫过程中伯醇羟基回转取向运动需要克服的能垒增加,毛白杨木粉与聚丙烯塑料的相容性更好,结合更紧密,界面强度更强,性能更加稳定。     

Surface modification of polymers by ion-assisted reaction

This paper deals with a new surface modification technique of polymers, the so-called ion-assisted reaction (IAR) to improve the surface properties of polymers and provides outstanding experimental results regarding wettability and adhesion of various polymers. In the IAR, polymer surfaces were subjected to low energy ion irradiation at different dosage in reactive gas environment. Dramatic improvements in wettability and surface energy are observed for the IAR-treated polymer surfaces and can be explained by the addition of functional groups, responsible for the increase of polar component in surface energy. The formation of functional groups results from the interaction among ion, reactive gas and polymer chain involved in IAR treatment, depending on the reactive ion species, the flow rate of the reactive gas and the irradiating ion fluence. The improvement in adhesion between the IAR-treated polymers and coating materials was explained in terms of the increased surface energy as well as surface roughness in the polymers modified by the IAR and possible adhesion enhancement mechanism is to be discussed.     

氧化镁填料的表面辐射接枝改性

本文采用共辐照方法将甲基丙烯酸甲酯(MMA)接枝到氧化镁MgO)粉末填料上,用傅里叶红外光谱和X射线衍射对接枝物进行了表征,并利用ESCA、SEM以及接触角测定对其表面性质进行了研究。将接枝改性后的MgO作为高密度聚乙烯(HDPE)的填料,实验结果表明,表面改性后的MgO在聚合物基质中的分散性得到明显改善,填入改性MgO的HDPE其断裂强度和断裂伸长率均有明显提高,且热稳定性也得到了显著的提高。     

High density polyethylene and silane treated silicon nitride nanocomposites using high-density polyethylene functionalized with maleate ester: Mechanical,tribological and thermal properties

In this study, attempt has been made to improve the overall performance of high-density polyethylene (HDPE) composites by blending with silane treated silicon nitride (SN) using HDPE grafted dibutyl maleate as compatibilizer. A small quantity of surface modified nanoclay has also been added in order to improve the mechanical properties. The mechanical properties show that both silane modification of silicon nitride accompanied by nanoclay addition has led to the substantial enhancement in mechanical properties. In addition, compatibilization has further improved the mechanical properties showing 10% (w/w of silicon nitride) as optimal compatibilizer content. The wear results showed that, as SN content increased, the slide wear loss decreased. Addition of SN along with compatibilizer also improved the thermal stability of the nanocomposites.     

改性芳纶纤维增强木粉/高密度聚乙烯复合材料的力学性能

采用螺杆挤出机研究了添加连续芳纶纤维增强木粉/高密度聚乙烯（CAF-WF/HDPE）复合材料,为改善CAF与WF/HDPE复合材料界面相容性,分别采用磷酸和硅烷偶联剂处理纤维。对比表面处理前后的CAF形态分析显示,经过处理的CAF表面粗糙度增加;采用磷酸和硅烷偶联剂处理,纤维束从基体中的拔出强度分别提高了94.9%和77.6%,表明处理后的CAF与WF/HDPE复合材料的界面结合强度有所提高。对比WF/HDPE复合材料,在挤出成型过程中加入未处理CAF,CAF-WF/HDPE复合材料拉伸强度、弯曲强度和冲击强度分别提高了32.1%、35.1%、515.1%;CAF采用硅烷偶联剂处理后,CAF-WF/HDPE复合材料对应的力学性能分别提高了42.0%、37.4%、550.2%。动态力学分析表明:表面处理后CAF与WF/HDPE复合材料的界面相容性得到改善。      

铝矾土改性竹粉/HDPE复合材料性能

为制备高性能的木塑复合材料,扩展其应用领域,采用A-171硅烷偶联剂对竹粉进行表面改性,并添加一定量的铝矾土,经热压成型制备了竹粉/高密度聚乙烯(HDPE)复合材料。分析了铝矾土用量对竹粉/HDPE复合材料力学性能、耐热性和摩擦性能的影响。采用XRD分析了铝矾土的结晶特性,利用SEM和EDS分析了竹粉/HDPE复合材料的断面形貌和表面元素分布情况。结果表明:加入适量铝矾土后,竹粉/HDPE复合材料的力学强度、耐热性及耐磨性能得以改善。铝矾土在竹粉/HDPE复合材料基体中分布均匀,可有效承担载荷,同时提高了竹粉/HDPE复合材料的结晶性能,降低了竹粉/HDPE复合材料在外在应力下引起的变形和破坏;但铝矾土用量过高,分布不均匀,容易形成团聚现象,导致竹粉/HDPE复合材料的力学强度和耐磨性降低,线性热膨胀系数增大。     

等离子改性条件对PEGDA/HEMA凝胶亲水性及表面能的影响

采用氩等离子对聚乙二醇双丙烯酸酯(PEGDA)/甲基丙烯酸-2-羟基乙酯(HEMA)共聚物凝胶进行表面改性,对膜材料进行了光电子能谱(XPS)分析,并讨论了等离子处理时间及功率对凝胶亲水性及表面能的影响。研究结果表明,经等离子处理后凝胶表面引入了含氧极性基团,氧的含量从未处理的23%增加到26%,使材料亲水性得到改善;由于引入极性基团,材料的表面能随等离子处理时间和功率的增加而增加,从未处理前的45.9 mJ/m2增加到72.5 mJ/m2,极性力分量γPs随等离子体处理功率和时间的变化规律与表面能γs基本一致。     

Effect of oxyfluorinated multi-walled carbon nanotube additives on positive temperature coefficient/negative temperature coefficient behavior in high-density polyethylene polymeric switches

Multi-walled carbon nanotubes (MWCNTs) were embedded into high-density polyethylene (HDPE) to improve the electrical properties of HDPE polymeric switches. The MWCNT surfaces were modified by oxyfluorination to improve their positive temperature coefficient (PTC) and negative temperature coefficient (NTC) behaviors in HDPE polymeric switches. HDPE polymeric switches exhibit poor electron mobility between MWCNT particles when the number of oxygen functional groups is increased by oxyfluorination. Thus, the PTC intensity of HDPE polymeric switches was increased by the destruction of the electrical conductivity network. The oxyfluorination of MWCNTs also leads to weak NTC behavior in the MWCNT-filled HDPE polymeric switches. This result is attributed to the reduction of the mutual attraction between the MWCNT particles at the melting temperature of HDPE, which results from a decrease in the surface free energy of the C-F bond in MWCNT particles.     

云母粉表面改性提高云母纸拉伸强度的研究

利用硅烷偶联剂"分子桥"作用对云母粉进行表面处理,通过自乳化改性的环氧树脂和聚丙烯酰胺,使云母粉表面桥联的环氧基团发生交联反应,显著提高云母纸拉伸强度。结果表明:当硅烷偶联剂、改性环氧树脂、聚丙烯酸胺的质量分数分别为0.5%、1.0%、0.5%时,云母纸拉伸强度由72.17 N/m提高到151.3 N/m。硅烷偶联剂水解产生的硅羟基与云母表面的羟基发生化学键的结合,另一端的氨基与改性环氧树脂中的环氧基团反应,增强了改性环氧树脂对云母表面的结合力。     

Influence of functionalization of multi-walled carbon nanotubes on the properties of ethylene vinyl acetate nanocomposites

Commercially available multiwalled carbon nanotubes (MWNT) were chemically modified by amine, acid and silane and their ethylene vinyl acetate (EVA) based nanocomposites were prepared. Unmodified and modified nanotubes were characterized by thermogravimetry, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy. Early degradation of modified nanotubes from the thermogravimetry study proved the presence of functional groups on nanotube surface. Increase in D-band to G-band ratio and a shift in radial breathing mode peaks from the Raman spectra indicated the generation of surface defects due to functionalization and variation in van der Waals force of attraction between nanotube aggregates on modification. The unmodified nanotubes improved the tensile strength by 30% with 4 weight% of filler. Amine modification imparted further increase in strength due to the presence of functional groups on the nanotube surface and the subsequent better dispersion of the nanotubes in the polymer matrix. The silane treatment imparted maximum improvement in various properties of the nanocomposites. The nanotubes provided better thermal degradation stability and also higher thermal conductivity to virgin EVA. The results were well supported by the morphological as well as swelling study of the various samples.     

Alumina coatings on PMMA: optimization of adherence

Alumina is deposited on polymethyl methacrylate (PMMA) using the RF magnetron sputtering method. The adhesion is characterized by means of a 180° peeling test and a fragmentation test. The surface energy of the materials is determined by measuring the contact angles using the two liquids method. The plasma surface treatment of the polymer help to smooth it and increase its surface energy. The modifications of the dispersive and polar components of this energy depend on the type of the plasma-gas used. Oxygen rich plasmas, such as air or carbon dioxide, allow the surface polarity of the polymer to be increased by a superficial oxidation whilst limiting the reticulation. They give better adhesion values. The analysis by ATR-FTIR displays the reticulation phenomenon for the extended application of argon plasma at low power. The RBS analysis shows that the quantity of argon incorporated into the alumina deposit is dependent on the operating conditions, particularly the pressure in the sputtering chamber. Different values of surface energy are due to the variations in composition. The alumina films with the lowest percentage of argon have the highest polar component. Their adhesion to the PMMA is also the highest. The best adhesion of alumina on PMMA is obtained for a polymer activation during a short time (10 s), by means of an oxygen rich plasma (CO₂) and for alumina coatings which have the lowest argon content (p = 1 Pa).     

表面改性处理对气相生长碳纤维的微观结构影响

为了使气相生长碳纤维(VGCF)能更好地作为高分子基体的增强材料,采用双氧水和硝酸(H₂O₂和HNO₃)二步处理法、硅烷偶联剂处理法及H₂O₂和HNO₃处理后再用硅烷偶联剂处理的联用改性法分别对VGCF进行表面改性处理,研究表面改性对VGCF微观结构的影响。利用AFM、FTIR、TG和XRD比较分析了改性处理对VGCF的表面微观结构、官能团、热稳定性和晶格等的影响。结果表明：3种处理方法对VGCF晶格无明显影响;H₂O₂和HNO₃二步处理法能在纤维表面接枝羧基等含氧基团;硅烷偶联剂处理法能使纤维表面接枝硅氧烷低聚物;H₂O₂和HNO₃处理后再用硅烷偶联剂处理联用改性VGCF,能使其表面接枝上更多的硅氧烷低聚物,有利于提高VGCF与高分子材料的亲和性。     

Coupling of HDPE/hydroxyapatite composites by silane-based methodologies

Several coupling treatments based on silane chemicals were investigated for the development of high density (HDPE)/hydroxyapatite (HA) composites. Two HA powders, sintered HA (HAs) and non sintered HA (HAns), were studied in combination with five silanes, namely y-methacryloxy propyltrimethoxy silane (MEMO), 3-(2-aminoethyl)aminopropyltrimethoxy silane (DAMO), vinyltrimethoxy silane (VTMO), 3-aminopropyltriethoxy silane (AMEO) and trimethoxypropyl silane (PTMO). The HA particles were treated by a dipping in method or by spraying with silane solutions. After drying, the treated powders were compounded with HDPE or HDPE with acrylic acid and/or organic peroxide and subsequently compression molded. The tensile test specimens obtained from the molded plates were tensile tested and their fracture surfaces were observed by scanning electron microscopy (SEM). For the sintered HA (HAs) composites, the most effective coupling treatments concerning stiffness are those based on MEMO and AMEO. The low influence of these coupling procedures on strength is believed to be associated to the low volume fraction and the relatively smooth surface of the used HA particles. For the non-sintered HA (HAns) composites, it was possible to improve significantly both the stiffness and the strength. Amino silanes demonstrated to be highly efficient concerning strength enhancement. The higher effectiveness of the coupling treatments for HAns filled composites is attributed to their higher particle surface area, smaller particle size distribution and expected higher chemical reactivity. For both cases, the improvement in mechanical performance after the coupling treatment is consistent with the enhancement in interfacial adhesion observed by SEM.     

氧气等离子体处理对CFRP表面特性及胶接界面力学性能的影响EI北大核心CSCD

为改善碳纤维增强复合材料(CFRP)胶接界面力学性能,采用低温氧气等离子体处理设备对CFRP进行表面处理。利用接触角测量仪、扫描电子显微镜(SEM)、原子力显微镜(AFM)、X射线光电子能谱(XPS)对CFRP表面润湿性、表面能、表面形貌、表面化学组分等进行表征,通过双悬臂梁实验(DCB)对CFRP胶接界面力学性能进行研究。结果表明:随氧气等离子体处理时间从0 s增加至30 s,表面水接触角从97°降至29°,CFRP表面润湿性达到最佳,极性分量占比显著增多;随处理时间的增加,CFRP表面粗糙度和最大高低差降低,形成较多谷峰分布的纳米级沟壑,基体表面积增大;同时,表面C—O和C■O等含氧极性官能团含量明显增加,C—C/C—H和Si—C官能团含量减少,表面污染物得到有效清除和转化;与未处理相比,经氧气等离子体处理20 s后,CFRP胶接界面最大剥离载荷和Ⅰ型断裂韧度分别提高了1.01倍(62.73 N)和1.92倍(649.21 J/m 2)。研究发现,氧气等离子体处理可以显著改善CFRP表面物理化学特性,有利于CFRP与胶黏剂更好的黏结,提高胶接界面剥离强度与韧性。     

Surface properties and adhesion of maleinized polyethylene films

The wettability and the adhesion of polyethylene films were improved by introducing polar groups in the polymer chains. The surface properties of films grafted with maleic anhydride (MA) were investigated. The wettability was found to be dependent on the MA content, on the film preparation conditions and on the hydrolytic process of the anhydride groups. The kinetics of the hydrolysis indicated a restructuring of the polymeric surface due to the movement of the polar groups towards the surface; it did not influence the adhesion properties. The behaviour of the maleinized films was compared with oxygen plasma treated materials, which showed a better wettability, but a worse adhesion on polar substrates than the maleinized polyethylene. These results were explained on the basis of X-ray photoelectron spectroscopic analyses, by which the main functional groups present at the surface were identified and quantitatively determined. © 1998 Chapman & Hall