马来酸酐接枝氯化聚丙烯的表面性质及粘接作用

研究了马来酸酐在氯化聚丙烯分子链上的接枝对其表面性质的影响,探讨了马来酸酐接枝氯化聚丙烯与聚丙烯及金属的粘接作用及耐水性。结果表明:随着MAH接枝率的增加,水与CPP-g-MAH的接触角逐步减小,CPP-g-MAH的表面能及极性部分增大;CPP-g-MAH对不锈钢、聚丙烯有良好的粘接作用,其粘接性能要明显优于CPP及市售的TS-2聚丙烯胶粘剂,随着接枝率的增加,粘接强度增大;CPP-g-MAH对聚丙烯的粘接作用具有良好的耐水性,经96 h 100℃沸水的浸泡,粘接强度没有发生明显下降。     

聚丙烯膜电晕处理及表面极性衰减机理的研究

电晕处理赋予聚丙烯(PP)膜表面丰富的极性基团,显著提高材料表面能,进而提高了材料复合、镀铝等粘接强度。极性衰减是聚合物材料在电晕处理后出现的一个普遍现象,对镀铝牢固性以及后期的复合强度有着至关重要的影响。本文从基体材料的结构、结晶、电晕参数、助剂等方面对材料的电晕结果和电晕表面极性保持性进行深入分析,探讨提高聚丙烯的粘贴牢固度的方法。     

不同改性剂对PP/木粉复合材料性能的影响

研究了苯甲酸(BA)、硬脂酸(SA)、甲苯-2,4-二异氰酸酯(TDI)对聚丙烯/木粉复合材料的改性效果。结果表明,木粉经改性剂处理后,表面极性减弱,与聚丙烯的界面张力降低,相容性提高;所有改性剂均可提高复合材料的拉伸强度、冲击强度以及熔体流动性能,但对弯曲强度影响不大。用TDI/SA复合处理木粉,复合材料的综合性能最好。扫描电镜(SEM)分析表明,木粉经过处理后,木粉与聚丙烯间界面较模糊。     

氨化与磺化改性橡胶混凝土机理及强度研究

为改善橡胶混凝土的强度,本工作选用尿素和NaHSO3两种改性剂对橡胶颗粒进行氨化与磺化改性。借助傅里叶红外光谱仪验证引入的极性亲水基团,利用水接触角试验仪分析改性橡胶的亲水性能,通过粘接强度试验和抗压强度试验研究改性橡胶对橡胶混凝土强度的提升效果,用扫描电子显微镜(SEM)表征橡胶混凝土的微观破坏形貌。结果表明:氨化改性在橡胶颗粒表面引入羰基和氨基等,磺化改性在橡胶颗粒表面引入羟基和磺酸基等;与普通组相比,氨化与磺化改性后,改性橡胶-水接触角分别降低31°、35°,改性橡胶与水泥净浆的粘接强度分别提升44%、53%,改性橡胶混凝土的抗压强度在不同橡胶粒径与掺量条件下均得到提升;SEM结果表明极性亲水基团的引入能较好地提升橡胶颗粒与胶凝材料的粘接性能,有利于改善两者结合界面薄弱的问题,增强橡胶混凝土的整体强度。     

反应挤出制备极性共聚聚丙烯热熔胶

聚丙烯(PP)热熔胶缺乏极性,在粘接极性材料时性能较差。文中使用反应挤出在PP及共聚PP分子链上引入马来酸酐(MAH)基团,提高其极性,获得了PP极性热熔胶。使用多种粘接基材评价了该热熔胶的粘接性能,研究了极性、表面粗糙度、分子链结构对粘接性能的影响。结果表明,反应挤出接枝MAH可以显著提高PP热熔胶与极性材料的粘接能力,并且发现织物样品的剥离强度强于薄膜样品。此外,MAH在共聚PP上的接枝率高于均聚PP,使得共聚PP的剥离强度也较高。     

酚醛树脂的改性及其对聚氨酯/金属粘接性能的影响

为了解决Chemlok218为粘接剂时，室温下聚氨酯(PU)/金属粘接效果差的问题，采用一种高活性的PU改性剂，对Chemlok218中的酚醛树脂(PF)进行改性获得PF@NCO，在Chemlok218涂层与PU间形成一层过渡层，FTIR、TG分析表明：PU改性剂中NCO基团与PF中的羟基反应生成氨基甲酸酯基团。与Chemlok218涂层相比，PF@NCO过渡层表面能提高，与PU相容性增加。当Chemlok218与PU改性剂的质量比为80∶20时，PF@NCO-20的剥离强度达到23.4 kN·m^-1，比纯Chemlok218提高了58.1%，整个PU/金属粘接试样无粘接薄弱点及缺陷。为解决室温下PU/金属的粘接强度问题提供借鉴。     

环境湿度对等离子体处理聚乙烯木塑复合材料表面时效性的影响

利用接触角、扫描电镜(SEM)、红外光谱(FT-IR)、X射线光电子能谱(XPS)和胶接强度等分析方法研究了湿度对等离子体处理聚乙烯木塑复合材料表面时效性的影响。结果表明,不同的湿度对表面处理的时效性影响不同。随时间的延长,23%湿度下放置的试样,表面C元素含量逐渐增加,O元素含量逐渐降低,含氧极性基团逐渐减少,材料表面粗糙度变化不大,粘接强度下降;而84%湿度下放置的试样,表面C元素含量先增加而后降低,O元素含量先降低而后增加,含氧极性基团先减少而后增多,材料表面出现微裂纹,粘接强度先降低而后增大。湿度较大的放置环境对等离子体处理材料表面的时效性影响更大。     

马来酸酐接枝氯化聚丙烯的制备和性能研究

以马来酸酐(MAH)为接枝单体、过氧化苯甲酰为引发剂,采用熔融接枝法改性氯化聚丙烯(CPP)。采用红外和核磁对产物进行表征,计算了改性产品的接枝率,系统探讨了引发剂用量、反应温度、接枝率对接枝产物酯溶性和在聚丙烯(PP)基材表面附着力和粘接强度的影响及原因。结果表明:MAH接枝CPP改变了产品极性,提高了产品在乙酸乙酯中的溶解度,在反应条件适宜时也提高了产品在PP基材表面的附着力。当过氧化苯甲酰(BPO)用量为0.05份,100℃时,接枝改性CPP在乙酸乙酯中溶解度最大(9.58g),较未改性CPP提升了4.67倍,在PP基材上的附着力最好(国际0级),粘接强度最大(0.689MPa)。     

复合表面改性剂处理纳米CaCO3粒子填充聚丙烯的结晶形态及力学性能

利用差示扫描量热仪(DSC)和X射线衍射仪(XRD)研究了复合表面改性剂处理纳米C aCO3粒子对聚丙烯结晶形态的影响,并与单一偶联剂表面处理纳米C aCO3粒子进行比较,结果表明,复合表面改性剂处理纳米C aCO3粒子比单一偶联剂表面处理纳米C aCO3粒子有着更强的β晶诱导效应,可使复合材料β晶型的相对含量增加约为20%;而对于熔融温度和结晶度而言,其影响结果基本相同。力学性能研究表明,与单一偶联剂表面处理纳米C aCO3粒子填充聚丙烯相比,复合表面改性剂处理纳米C aCO3粒子填充聚丙烯的力学性能得到进一步改善和提高,尤其是冲击强度和断裂伸长率。     

聚丙烯(PP)纤维表面改性及其在混凝土中的应用

混凝土中加入纤维可以大大增强混凝土的强度,其中聚丙烯纤维增强混凝土复合材料以其优异的性能正得到越来越广泛的应用,研究发现聚丙烯纤维的表面微观结构及其与水泥界面之间粘接力的强弱是影响复合材料性能的重要因素.综述了近年来聚丙烯纤维的表面改性及其在混凝土中的应用.     

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     

聚丙烯共混改性研究

将少量（１％）自制的甲基丙烯酸十八醇酯（ＳＭＡ）与丙烯酰胺（ＡＭ）共聚物Ｐ（ＳＭＡ－ＡＭ）添加剂聚丙烯（ＰＰ）中进行共混，能大幅度提高聚丙烯的亲水性和粘合强度。Ｐ（ＳＭＡ－ＡＭ）的加入，改善了ＰＰ的流变性能，对ＰＰ的结晶度和拉伸强度影响不大。俄歇电子能谱（ＡＥＳ）分析表明，Ｐ（ＳＭＡ－ＡＭ）在ＰＰ共混物表面富集。     

废印刷电路板非金属粉填充聚丙烯的实验

采用熔融共混方法制备了废印刷电路板非金属粉/聚丙烯复合材料,并通过非金属粉润湿性能和缺口冲击断面形貌观察,分析研究了非金属粉添加对聚丙烯复合材料力学性能的影响。结果表明,非金属粉可以同时改善非金属粉/聚丙烯复合材料的拉伸、弯曲、低温冲击性能,但室温冲击性能降低;其中拉伸强度、拉伸模量、弯曲强度、弯曲模量、低温冲击强度最大增幅分别为16.3%、41.5%、63.5%、100%、45.7%;废印刷电路板非金属粉可作为聚丙烯的增强增韧填料。     

P(NIPAAm-PEGMA)接枝聚丙烯多孔膜表面的抗污染及自清洁性能

以等离子体引发方法制备了聚(N-异丙基丙烯酰胺-聚乙二醇甲基丙烯酸酯)(P(NIPAAm-PEGMA))接枝的聚丙烯(PP)多孔膜。考察了改性膜水通量及表面润湿的温敏性质,并研究了其表面抗牛血清白蛋白(BSA)污染及自清洁性能。结果表明,聚乙二醇(PEG)侧链引入后,P(NIPAAm-PEGMA)保留了体积相转变性质,并在低临界溶解温度(LCST)上下均能展现良好的表面亲水性。得益于表面亲水性的改善,改性膜在过滤BSA溶液时的通量衰减率降低至18.8%。经简单的变温水清洗,BSA污染膜的水通量恢复率可达98.2%,且表面甚少污染物残留。P(NIPAAm-PEGMA)接枝链的亲水性及体积相转变是实现改性膜表面自清洁的原因。     

An effective surface modification of carbon fiber for improving the interfacial adhesion of polypropylene composites

A simple and effective modification for carbon fiber (CF) was presented in our work. CF was coated with ethylene–methyl acrylate–glycidyl methacrylate (E–MA–GMA) terpolymer through solution dipping. A uniform layer of 2.0 wt.% E–MA–GMA was confirmed on CF by IR, TGA and SEM. XPS showed that surface oxygen-containing functional groups were obviously increased after modification, which were advantageous to promote the reactivity of CFs. The treatment turned out to be helpful in enhancing the interfacial adhesion by micro-droplet experiment and the interfacial shear strength was 157% higher. The physical properties of PP/mCF composites were improved by static and dynamic mechanical analysis and the improvement was more noteworthy when maleic anhydride grafted PP (MAPP) was added to the matrix, which was consistent with the fracture morphology. The ultimate flexural strength, impact energy and tensile strength were increased by 139.3%, 233.9% and 126.1%. Besides, the mechanical performance of PP composites with 0–30 wt.% CFs were all significantly enhanced by CF surface treatment in combination with MAPP modification. We believed that the excellent performance was not caused by fiber length or crystallinity, it was mainly due to the superior interfacial interaction by intermolecular chain entanglement, as well as chemical reaction between E–MA–GMA and MAPP.     

Progress in Polypropylene Nanocomposite Development

This article summarizes some of the highlights of newest developments in polypropylene (PP) clay nanocomposite research. Different property improvements, including mechanical performance enhancements, achieved by melt compounding of organoclay materials with PP and/or PP‐g‐MA are presented.     

Modification of polypropylene surface by CH<Subscript>4</Subscript>–O<Subscript>2</Subscript> low-pressure plasma to improve wettability

The aim of this work is to study the effect of surface treatment of a polypropylene film with low-pressure plasma using CH₄–O₂ mixture gas in an 80:20 ratio. The effect of the variation of the plasma treatment conditions has been studied to optimize the plasma effects. The film wettability has been analyzed by the study of the variation of free surface energy and its polar and dispersive components. The surface functionalization of the PP film was also analyzed by X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance infrared spectroscopy (FTIR-ATR) analysis. The surface topography was analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The CH₄–O₂ plasma treatment induces the ablation inherent of a traditional plasma treatment and polymerization mechanisms to take place simultaneously at the treated surface. The PP film treated with CH₄–O₂ plasma shows a remarkable improvement on the surface free energy mainly caused by surface functionalization as XPS reveals. Slight changes in surface topography are observed, but they do not contribute in a significant way to improve wettability.     

Immobilization of chitosan gel with cross-linking reagent on PNIPAAm gel/PP nonwoven composites surface

This study was to immobilize chitosan (CS), which is a biodegradable and antibacterial polymer, on poly(N-isopropylacrylamide) (PNIPAAm) gel/polypropylene (PP) nonwoven composites surface for wound dressing applications. PP nonwoven has been extensively used due to its porosity, allowing ventilation, high surface area and excellent mechanical properties. However, the hydrophobic surface of PP nonwoven limits its applications; in this study, we used the plasma-activation treatment and subsequently UV-light graft polymerization of NIPAAm gel to improve its hydrophilicity. Chitosan was immobilized onto PNIPAAm gel/PP nonwoven composites surface using the cross-linking agent, glutaraldehyde (GA). This complex was characterized by scanning electron microscopy (SEM). The results indicated that the wettability of the composite was improved after plasma treatment and photo-induced graft polymerization and chitosan was successfully immobilized onto the surface of PNIPAAm gel/PP nonwoven composites through cross-linking process. Finally, the preliminary result shows that chitosan hydrogels displayed antibacterial ability to Escherichia coli and Staphylococcus aureus. The (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide) (MTT) method indicated that the porous chitosan sponge exhibited good biocompatibility to fibroblast cells.     

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.     

Preparing PP/clay nanocomposites using a swelling agent

Polypropylene (PP)/clay nanocomposites (PPCN) were prepared using a swollen organoclay, which had a larger interlayer spacing than pristine organoclay. The organoclay was first treated with a swelling agent (maleic anhydride, MA) and a co-swelling agent in solution. Then, it was melt blended with PP-g-MA to generate a pre-intercalated composite (PIC). Finally, the PIC was blended with PP to obtain a PPCN, which contained small amounts of PP-g-MA. The materials were characterized using X-ray diffraction (XRD), Scanning electron microscopy, Transmission electron microscopy (TEM), and TGA. The XRD graphs showed that the basal spacing of the pristine clay treated with MA was 1.6 nm, which was larger than that of the original clay, but smaller than that of the organoclay. The XRD graphs of the organoclay treated with MA showed double peaks at 3 and 5.5°. As the ratio of MA to the organoclay increased, the peak at 5.5° decreased gradually. TEM micrographs indicated that the clay layers in the pre-intercalated blends were still stacked in an orderly manner. However, partial exfoliation of the clay layers was observed in the PPCN. The nanocomposites prepared with the aid of swelling agents contained some PP-g-MA. Good dispersion of the clay layers gave the PPCN greater thermal stability and an enhanced storage modulus, which indicated a reinforcing effect of the clay in the PP matrix. The increased T_g (derived from Dynamic mechanical analysis) of PPCN implied that the PP macromolecules were intercalated between interlayers of the silicate.