【作者】 邓康清；

【导师】 姜兆华； Mitchell A.Winnik；

【作者基本信息】 哈尔滨工业大学 ， 化学工程与技术， 2009， 博士

【摘要】 热塑性聚烯烃（Thermoplastic polyolefins, TPO）因其具有重量轻、力学性能好、价格低廉和可重复利用等特点而被广泛用作汽车保险杠、挡雨板、仪表板和其它一些汽车部件。但是，用TPO制成的汽车塑料部件表面存在喷涂的漆层易脱落的问题。解决该问题的主要方法是在TPO和漆层间引入一层粘结促进剂（Adhesion promoter，AP）,常用氯化聚烯烃（Chlorinated polyolefins,CPO）。虽然AP有效地促进了涂料与TPO表面的粘结，但仍然存在耐久性不足的问题。而通过对CPO与TPO的界面和CPO促进涂层与TPO粘结性等的深入研究，可为解决汽车塑料部件的耐久性奠定技术基础。本研究通过脉冲式原子力显微镜（PFM-AFM）、激光扫描聚焦荧光显微镜（LSCFM）、广角X射线衍射（WXRD）、扫描电镜（SEM）、动态力学分析（DMA）、差示扫描量热（DSC）和偏光光学显微镜（POM）等多种现代仪器分析技术及搭接剪切、拉伸等实验技术，对聚丙烯（isotactic polypropylene, iPP）/乙烯-丁烯共聚物（Ethylene-butene copolymer, EBR）新型热塑性聚烯烃与CPO的相容性、界面结构特性和界面粘结特性进行了实验研究和理论分析。通过相互作用能密度（Bij-Bc）从理论上分析了iPP、EBR和CPO双组分共混物的相容性，运用LSCFM、SEM和DMA等技术的研究表明：iPP/EBR和iPP/CPO共混物是不相容的；EBR/CPO共混物在熔融状态下相容，在固体状态下部分相容。随EBR含量增加，iPP/EBR共混物的相容性有改善的趋势，并建立了iPP/EBR的相结构模型。采用衰减全反射-傅立叶红外光谱（ATR-FTIR）表征了注射成型TPO板的表面组成。结果表明，虽然试样TPO板中EBR含量一定，但其表面的EBR含量却随位置的不同而不同。当EBR含量为12mass%时，从近浇口到远离浇口，TPO板表面的EBR含量呈增加趋势；当EBR含量为25mass%时，TPO板表面的EBR含量与离浇口的距离没有明显的关系。对TPO板的表面和近表面的形态和结构研究表明，在TPO板表面存在几百微米厚的皮层，皮层中存在明显的iPP穿晶层和EBR；从近浇口到远离浇口，皮层的厚度减小，TPO板表面的EBR相的尺寸增加。用高分辨率的PFM-AFM表征了TPO/CPO/TPO粘结试件的界面结构特性。结果表明，在iPP和CPO间是一个21nm的很陡的界面；未经过退火处理的CPO包覆的TPO板，TPO和CPO间是一个28nm宽的界面；而经过120°C退火处理20min的CPO包覆TPO板的界面宽为58nm。说明CPO促进与TPO的粘结是由于CPO优先与EBR作用的结果。PFM-AFM观察还发现，TPO/CPO界面存在一个硬度与周围很不同的600~1500nm宽的“过渡带”。提出了CPO促进与TPO界面粘结的机理和CPO/TPO界面区结构模型。分析了注射成型TPO板的配方和表面组成分布对粘结试件的断裂模式和TPO板的界面粘结特性的影响。随TPO板中的EBR含量增加，或TPO板的位置从近浇口变为远离浇口，粘结试件的断裂模式由界面破坏转变为混合破坏。随TPO板中EBR含量的增加，断裂强度和粘结能呈上升趋势；从近浇口到远离浇口，断裂强度和粘结能增加。分析表明，断裂强度和粘结能随TPO板配方的变化而变化是与TPO板中EBR含量和TPO本体强度相关的；断裂强度和粘结能随TPO基材离浇口距离的变化而变化是与TPO板表面的EBR含量（即表面组成分布）和皮层厚度相关的，也就是与最初注射成型时的流场相关。研究了CPO的结晶性及其与TPO粘结性能的相关性。CPO是一个低结晶度、有两个热转变峰的聚合物，其结晶度和玻璃化温度Tg均随老化时间的增加而增加；CPO的玻璃化温度Tg与结晶度Xc、CPO的屈服应力与结晶度Xc、TPO/CPO/TPO粘结件的断裂强度与CPO氯含量之间均存在线性关系。在此基础上，建立了CPO/TPO粘结力模型，该模型能很好地预测界面粘结实验结果；并提出了改善CPO/TPO界面粘结性能的方法。更多还原

【Abstract】 Thermoplastic polyolefins (TPO) have become increasing popular alternatives tosteel-made automotive parts such as painted bumper, fascia, filler, panels and otherinterior and exterior parts because of its lightweight, low cost, good mechanicalproperties and recyclability. However, this kind of painted automotive parts madefrom TPO has the disadvantage of paint failure. An important method to overcomethis problem is the application of a layer of adhesion promoter (AP), oftenchlorinated polyolefins (CPO). Although AP can promote the adhesion of paint toTPO effectively, paint failure during the period of guarantee is still a serious problemin automotive industry. So, the research on the interface of CPO and TPO, and howCPO promote coating adhesion to TPO substrate will lay a technical foundation onthe solving of the problem of the wear of automotive parts.In this study, the experimental investigations and theoretical analysis on themiscibility, the interface, and the adhesion between iPP/EBR thermoplasticPolyolefins and chlorinated polypropylene (CPO) were carried out by many advancedanalytical instruments and experimental technics, such as pulse force mode-atomicforce microscopy (PFM-AFM), laser scanning confocal fluorescence microscopy(LSCFM), wide angle X-ray diffrection（WXRD）, scanning electronic microscope(SEM), dynamic mechanical analysis (DMA), differrential scanning calorimeter(DSC), polarized optical microscopy (POM), lap-shear test and tensile test, etc.The morphology and the miscbility of iPP, EBR and CPO binary blends wereanalyzed by binary interaction energy density (Bij-Bc). The theretical analyzed resultswere further verified by LSCFM, SEM and DMA, etc. The conclusion was obtainedthat iPP/EBR and iPP/CPO blends are immiscible, EBR/CPO blend is miscible inmelt and partially miscible in solid state. The further inverstigation on themorphology of iPP/EBR blend showed that there was some improvement on themiscbility of iPP/EBR blend with the increasing of EBR content. The phase structuremodel of iPP/EBR blend was established.The composition at the surface of the injection-molded TPO plaques wascharacterized by attenuated total reflectance-Fourier transform infrared (ATR-FTIR).The result shows that although the amount of EBR content in TPO plaque is stable,the EBR content at surface of TPO12plaque changes with position of TPO plaque.The EBR content at the surface of TPO12plaque increases from near gate to far fromthe gate, but there is no obvious difference in EBR content at surface of TPO25plaque with respect to the gate. The morphology at the surfce and the near surface of TPO plaques was studied.The result shows there exists a skin layer with hundreds of micrometers thickness inTPO plaque. Within the skin layer, there is a pronounced transcrystalline layer andsignificant amounts of EBR. The thickness of the skin layer decreases and thedimension of EBR phase at the surface of TPO plaque increases from near the gate tofar from the gate.The interfacial structure of TPO/CPO/TPO lap shear joints was investigated byhigh resolution PFM-AFM. The results revealed a sharp interface (21nm) betweeniPP and CPO, a wider interface (28nm) between TPO and CPO without annealing,and an even broader interface (58nm) between TPO and CPO subjected to annealingat120°C for20min. These results are in accord with the idea that CPO interactspreferentially with the impact modifier as it promotes adhesion to TPO. A novelobservation from the PFM-AFM results was the presence in TPO/CPO samples of atransition zone of very different stiffness with a width on the order of600to1500nm.The interfacial adhesion mechanism of CPO to TPO and the interfacial structuralmodel were proposed, too.The adhesion of CPO to injection-molded TPO plaques and the fracture mode oflap joints varied both with the composition of TPO plaques and the compositiondistribution at the surface of TPO plaques. The fracture mode of the adhesion jointschanged from interfacial failure to mixed failure with the increasing of EBR contentin TPO plaque or from near the gate to far from the gate of TPO plaque. The fracturestrength and adhesion energy increased with the increasing of EBR9content in TPOblends, they increased from near the gate to far from the gate, too. The analyzedresults shows that the changing of the fracture strength and the adhesion energy withthe composition of TPO plaques was correlated to the EBR content in TPO plaqueand the cohesive force of TPO plaque, the changing of the fracture strength and theadhesion energy with the position at the surface of TPO plaques was correlated to theEBR content (also the composition distribution) at the surface of TPO plaques andthe thickness of skin layer, which were actually correlated to the folw field of themelt.The crystallization of CPO and its correlation to the adhesion of CPO to TPOsubstrate were investigated. CPO is a low-crystallinity polymer with two meltingpeaks. Both the crystallinity Xcand the glass transition temperature Tgof CPOincrease with the ageing time, three types of linear relationship were revealed relatedto CPO: Tgof CPO to the crystallinity Xcof CPO, the yield stress of CPO to XcofCPO, and the fracture strength to the clorine content of CPO. Based on these results,the adhesion force model of CPO/TPO was established. The predicted results from this model met very well with the experimental results. The methods to improve theadhesion of CPO to TPO were proposed, too.更多还原