PP复合材料耐刮擦性能的研究

通过多指刮擦试验机对聚丙烯(PP)及其复合材料进行了系统的刮擦实验测试,采用光学显微镜观察了材料的刮擦损伤形貌,以研究PP及其复合材料的耐刮擦性能及损伤机理;通过差示扫描量热仪(DSC)测试了材料的结晶度,研究了耐刮擦助剂和磷酸盐成核剂对材料力学性能、结晶性能和耐刮擦性能的影响,以探讨材料力学性能、结晶性能与耐刮擦性能之间的关系。     

车用改性聚丙烯材料耐刮擦性能研究进展

综述了基体材料、填料、耐刮擦剂等对车用改性聚丙烯材料耐刮擦性能的影响,介绍了耐刮擦性能的测试方法以及国内常用的耐刮擦剂,并对车用改性聚丙烯材料耐刮擦性能的研究趋势进行了展望。     

玻璃纤维增强PBT复合材料刮擦行为研究

研究了玻璃纤维增强聚对苯二甲酸丁二醇酯(PBT)复合材料表面刮擦性能。采用自制刮擦实验设备,进行线性增加法向荷载模式的刮擦实验。通过对比不含玻璃纤维PBT材料刮擦实验结果,对不同玻璃纤维含量(10%、20%、30%)的PBT表面刮擦行为进行了系统的实验研究。探究了不同刮擦方向(平行于和垂直于玻璃纤维刮擦方向)对材料表面耐刮擦性能的影响。通过临界法向荷载和微观显微图像分析刮擦破坏机理。同时,也讨论了玻璃纤维含量变化对刮擦破坏模式和划痕形貌等的影响。结果表明,玻璃纤维含量的增加虽然可有效抵抗刮头刮入材料内部,但是容易使材料表面发生破坏。平行于玻璃纤维方向刮擦性能要优于垂直于玻璃纤维方向刮擦。     

聚丙烯复合材料的力学性能和耐刮擦性能研究

以聚丙烯(PP)、滑石粉(Talc)、SEBS和绒毛粉为原料,采用熔融共混方法制备了PP复合材料。分别研究了SEBS及绒毛粉对PP复合材料力学性能和耐刮擦性能的影响。利用交叉刮擦法对耐刮擦性能进行了表征。结果表明:在一定范围内SEBS具有增韧作用,但随着SEBS含量的增加,PP的拉伸强度、弯曲强度以及耐刮擦性能逐渐降低。随着SEBS含量的增加,ΔL逐渐增加;少量添加绒毛粉对复合材料除冲击强度以外的性能影响较小,添加少量绒毛粉便能显著提高材料的耐刮擦性能。随着绒毛粉含量的增加,ΔL值相应地降低。     

耐刮擦剂对高光PC/ABS合金性能的影响研究

使用丙烯酸酯类和硅油类耐刮擦剂对高光聚碳酸酯(PC)/丙烯腈–丁二烯–苯乙烯塑料(ABS)合金进行共混改性,研究这两类耐刮擦剂对高光PC/ABS耐刮擦性能、光泽和韧性的影响。结果表明,丙烯酸酯类耐刮擦剂可明显提高高光PC/ABS合金的耐刮擦性能,同时会降低高光PC/ABS合金的光泽度和韧性,综合考虑耐刮擦性能、光泽度和韧性,丙烯酸类耐刮擦剂的质量分数为10%时最佳;硅油类耐刮擦剂对高光PC/ABS合金耐刮擦性提高不明显,同时会降低高光PC/ABS的韧性和光泽度,不适合用于高光PC/ABS合金。     

汽车用耐刮擦改性聚丙烯的研制

制备了汽车用耐刮擦改性聚丙烯(PP),分析了不同耐刮擦滑爽剂、矿物填料、PP结晶度及增容剂等对材料耐刮擦性能的影响。结果表明,采用高结晶PP、较小粒径的矿物填料和反应型高聚硅氧烷制备的改性PP具有优异的耐刮擦性能,完全适用于汽车零部件。     

低散发耐刮擦汽车内饰用聚丙烯复合材料的研制

采用熔融挤出法制备了一种低散发耐刮擦汽车内饰用聚丙烯(PP)复合材料,研究了不同用量的耐刮擦剂和气味吸附剂对PP复合材料耐刮擦性能和气味散发特性的影响.结果表明,当耐刮擦剂和气味吸附剂的质量分数分别为1.5％和1％时,PP复合材料具有较优异的耐刮擦性能和低气味散发特性,且其力学性能不受影响.该复合材料已成功应用于各种汽车内饰件.     

汽车用PA6/ABS共混体系耐刮擦性能研究

研究了PA6/ABS的配比、玻璃微珠、硅酮、PTFE、成核剂、PMMA等组分对共混体系表面耐刮擦性能的影响。结果表明,确保材料力学性能优异的前提下,提高耐刮擦性的最佳方法是降低PA6的含量,PA6含量不大于50份时,体系的耐刮擦性较好。     

耐刮擦聚丙烯共混物的制备和性能研究

采用不同目数滑石粉(Talc)填充增强聚丙烯(PP),研究了聚烯烃弹性体(POE)、线性低密度聚乙烯(LLDPE)和相容剂(PP-g-MAH)对PP复合材料韧性的影响以及硅酮类耐刮擦助剂对材料刮擦性能的影响。结果表明:PP/POE/LLDPE/相容剂/Talc(质量比为57/10/10/3/20)复合材料综合力学性能最佳,而添加3份硅酮助剂(AS100)时,刮擦性能得到极大的改善,耐刮擦值(ΔL)可达到0.56。     

尼龙6对聚丙烯复合材料耐刮擦性能的影响

采用熔融共混方法,制备了聚丙烯(PP)/聚四氟乙烯(PTFE)/尼龙6(PA6)复合材料,研究了PA6对PP复合材料力学性能和耐刮擦性能的影响.采用光学显微镜(OM)等手段对聚丙烯(PP)复合材料的耐刮擦行为进行了研究.结果表明,均聚PP与共聚PP相比,显示出了优异的耐刮擦性;PA6增加了PP复合材料的模量和强度,从而改善了材料的耐刮擦性能.     

Determination of epoxy coating wet-adhesive strength using a standardized ASTM/ISO scratch test

A new approach for evaluating the wet-adhesive strength of epoxy-based coatings was carried out based on a recently standardized ASTM/ISO scratch test. A linearly increasing scratch normal load was applied during scratch to induce progressively increased delamination stress at the coating and steel substrate interface. Thus, the applied critical load to cause coating debonding can be experimentally determined. To find out the corresponding stress magnitude to incur coating debonding, finite element methods (FEM) modeling was conducted to analyze the stress fields around the scratch tip during scratching. The wet-adhesive strength is then quantitatively determined. Based on the above methodology, investigation on a set of model coating systems suggests that the critical load for coating delamination is significantly influenced by water exposure time, coating thickness, and substrate surface roughness. By combining the standardized scratch tests and FEM modeling, the proposed approach is found to be effective for quantitative assessment of epoxy coating wet-adhesive strength and for the development of high performance protective coatings for various industrial applications.     

A macroscopically nondestructive method for characterizing surface mechanical properties of polymeric coatings under accelerated weathering

The surface of coatings and plastics is the first target in any degradation process initiated by ultraviolet (UV) radiation or mechanical stress (via scratch and abrasion). Surface damage can lead to changes in optical, morphological, and mechanical properties and can result in pathways for ingress of moisture and corrosive agents. Current test methods for monitoring performance of protective coatings focus on chemical properties and optical properties, such as color and gloss measurements, or invasive tests such as abrasion and cross-cut adhesion. In this study, a macroscopically nondestructive performance protocol using nanoindentation metrology via a well-controlled scratch test was applied to evaluate the scratch resistance and monitor the surface mechanical property changes in a protective coating under accelerated weathering. Polyurethane (PU) coatings with different polyol compositions were chosen for this study. Coating specimens were exposed to high-intensity UV radiation at 55°C and 75% RH conditions. Exposed specimens were removed at specified UV exposure times for surface modulus/hardness and scratch resistance characterization via nanoindentation and scratch test. The effect of polyol type and UV radiation dose on the scratch damage (scratch morphology) was investigated and correlated with the surface hardness and modulus of the materials.     

The scratch test for strength and fracture toughness determination of oil well cements cured at high temperature and pressure

Recent advances in scratch test analysis provide new ways to relate measured scratch test properties not only to strength properties but fracture properties of materials as well. Herein, we present an application of such tools to oil well cements cured at high temperatures and pressures. We find a concurrent increase of strength and toughness of different oil well cement baseline formulations which we relate to the water-to-binder ratio for a series of cementitious materials prepared with cement and silica flour. The scratch test thus emerges as a self-consistent technique for both cohesive–frictional strength and fracture properties that is highly reproducible, almost non-destructive, and not more sophisticated than classical compression tests, which makes this ‘old’ test highly attractive for performance-based field applications.     

免喷涂外观美学树脂的应用

为了替代传统喷涂材料,制备了高性能免喷涂聚丙烯(PP)复合材料,该PP复合材料具有金属光泽的美学外观,减少喷涂工艺所带来的环境污染且降低成本。以PP树脂为基体,使用自制的颜料分散剂PDA–1和耐划伤剂SR–1制备具有优异耐划伤性的免喷涂PP复合材料。通过扫描电子显微镜观察颜料在树脂内部的分布,使用五指刮擦仪评估材料使用不同耐划伤剂的抗划伤性能。通过加入颜料分散剂PDA–1解决了免喷涂产品各向异性的缺陷,实现各向同性的免喷涂美学外观;自制的抗划伤剂SR–1具有优异的耐划伤性,满足汽车行业对材料的耐划伤需求(大众汽车标准PV3925)。     

Scratch behavior of extrusion and adhesive laminated multilayer food packaging films

Scratch‐induced puncture damages on adhesive and extrusion laminated multilayer food packaging films were investigated. Films were tested using a modified standardized linearly increasing load scratch test methodology, ASTM D7027‐05/ISO 19252:2008, which has successfully demonstrated an ability to correlate damages observed in field use of packaging films to laboratory findings. Samples were cross‐sectioned to view the evolution of damage in a layer‐by‐layer fashion to determine any potential weak‐link in the laminate. It was observed that the extrusion laminated film showed both superior scratch performance and superior layer adhesion with increasing scratch load, particularly upon severe film deformation. The extrusion lamination process may be used to produce strong, scratch‐resistant packaging films without the need for additional adhesive layers and the associated health and environmental concerns. Usefulness of the standardized scratch testing for evaluating performance of food packaging films and laminates is discussed. POLYM. ENG. SCI., 54:71–77, 2014. © 2013 Society of Plastics Engineers     

Environmental etch performance, and scratch and mar of automotive clearcoats

Environmental etch damage to automotive coatings, and scratch and mar of these coatings are an important element of customer satisfaction as well as a significant warranty repair consideration for automotive companies. The conditions that result in environmental etch are examined and a laboratory test proposed. Data from this test are compared to automotive hoods exposed in Florida. The performance of various crosslinking chemistries is discussed and the requirements for improved environmental etch are outlined. Scratch and mar performance of these systems is also reviewed. We have found that coatings respond to physical stress by elastic recovery, by plastic flow and by brittle fracture. Classifying types of damage in this way is important for understanding the chemistry needed for improved scratch and mar of coatings.     

Effect of high temperature annealing on scratch behavior of acrylonitrile styrene acrylate copolymers

The scratch behavior of butyl-acrylate rubber-modified styrene-acrylonitrile (ASA) upon high temperature annealing is investigated following the ASTM D7027/ISO 19252 linearly increasing normal load test methodology. The critical normal loads at the onset of the major deformation transitions along the scratch path, such as groove formation, scratch visibility, microcrack formation, and plowing, are reported and quantitatively analyzed. It is found that the scratch resistance improves with high temperature annealing, i.e., 30 °C above T_g, as compared to annealing below or around T_g. Microscopic investigation suggests that the increase in scratch resistance is related to the changes in surface morphology of the polymer. It is concluded that performing high temperature annealing enhances the scratch performance without compromising ASA bulk properties. Implication of the present study for improving scratch resistance of polymers is discussed.     

Computational modeling of inhibitor release and transport from multifunctional organic coatings

A computational code that was originally designed to model crevice corrosion was extended to multifunctional coatings on Al alloys exposed to thin layers of electrolytes. The model is able to calculate the transient distributions of potential, current density, and all chemical species concentration, enabling the dynamic simulation of inhibitor release, inhibitor transport, and sacrificial cathodic protection. The model has been applied to both inhibitor release from and aggressive anion capture by hydrotalcites (HTs) pigments in epoxy primer coatings applied to AA2024-T3. Computational studies were carried out to investigate the effects of HT/vanadate (HT/V) epoxy coating system parameters including scratch size, inhibitor release rate, Cl⁻ gettering rate (GR), cathodic kinetics on the bare AA2024-T3, and solution layer thickness on system performance. The analyses of the computational results have quantified the important factors controlling successful corrosion inhibition by inhibitor release from coatings. The pH-dependence of the steady state inhibitor release rate was found to be the most important parameter controlling system performance. Cl⁻ gettering can also reduce the aggressiveness of solution at long times, especially when considered in conjunction with inhibitor release. However, the ion exchange capacity required poses stiff design challenges involving the loading of the ion exchanger into the resin and the service conditions. The effectiveness of inhibition decreased significantly for the larger scratch sizes. The cathodic kinetics within the scratch play an important role in determining the ability of a given inhibitor to function effectively. When the scratch is the cathode in the galvanic couple with the substrate under the coating, inhibition was more effective. For the conditions simulated here, the net effect of a decreased solution layer thickness is to increase the protection ability of the system. The increase in the inhibitor concentration overcomes the decrease in the pH at the anode.     

Micro-scratch test for adhesion evaluation of thin films

In tribological applications, surface properties govern performance, and hence the utilization of coatings to tailor properties has become an essential component of materials technology. The most critical requirement for such coatings is adequate adhesion. Therefore, the need to measure coating/substrate interfacial strength and to characterize the factors influencing it is critical. However, the most common method currently used to characterize adhesion-the scratch test-is inadequate because it does not really measure adhesion. It is indicative of a relative measure of coating durability, which can be useful, at best, for quality control purposes. Consequently, the need for a test that can more accurately determine the adhesion characteristics of thin films is imperative. The development of a micro-scratch test and how it addresses some of the deficiencies of the conventional scratch test are discussed.     

Correlation between the wear resistance, and the scratch resistance, for nanocomposite coatings

The nanoscratch test, used in this study, quantitatively characterizes the scratch behaviour of coatings. Some of the obtained parameters are plastic and elastic deformation, critical load to start the scratch, chipping or other change in the scratch mechanism of the coating. The knowledge of the scratch mechanism allows the optimisation of the material behaviour. In the present study the scratch resistance with the wear resistance has been correlated for nanocomposite coatings. Knowledge of mechanical properties extracted from the scratch test, supports the optimization of the coating against wear. The study was applied to nanocomposite coatings with different polymer matrices, different percentages and nature of nanoparticles.