【作者】 刘其霞；

【导师】 晏雄；

【作者基本信息】 东华大学 ， 纺织工程， 2009， 博士

【摘要】 随着现代工业的发展,振动和噪声的危害正日益加剧,为了安全和环保,许多场合必须使用能够减振降噪的阻尼材料。高分子阻尼材料是新发展起来的一种新型材料,它是利用高分子的粘弹性来吸收振动的能量,将吸收的机械能或声能部分地转变为热能并耗散掉,从而起到降低振幅或减小振动能的作用。高分子阻尼材料已在交通工具、产业机械、建筑土木、家用电器、精密仪器和军事装备等领域获得了广泛应用。高新技术的发展对阻尼材料的要求愈来愈高,各领域都需要更多具有宽温域、高性能、智能化的阻尼材料。但目前多数阻尼材料不具有满意的减振、物理、机械等综合性能,尤其是减振和强度不能同时兼具,研制和开发综合性能优异的阻尼材料具有极其重要的意义。本论文正是在这一大背景下,在对多种阻尼改性方法的优缺点进行综合比较后,基于新近开发的由功能性有机小分子和极性聚合物组成杂化体系制备高性能阻尼材料的阻尼改性新方法,首次选取极性较大且具有阻尼性能较好的羧基丁腈橡胶（XNBR）作为基体聚合物,通过选用合适功能性有机小分子组成有机杂化体系得到具有较高损耗因子的阻尼材料,然后采用不同的途径对其性能进行进一步改善,开发出了一系列具有较大工程应用价值的高性能阻尼材料,并综合采用动态力学热分析（DMA）、差示扫描热分析（DSC）、傅立叶红外光谱（FT-IR）分析、扫描电镜（SEM）观察等分析测试手段,对其阻尼机理进行深入探讨,以期为今后该领域的研究工作提供一定的理论参考。本论文的主要研究内容与结论如下:1.二元有机杂化阻尼材料的制备及阻尼性能研究为了制备出高阻尼的有机杂化阻尼材料,本文首先经过一定理论分析和初步实验测试筛选出两种不同功能性有机小分子有机受阻酚2,2′-亚甲基双-（4-甲基-6-叔丁基苯酚）（AO-2246）和四[β-（3,5-二叔丁基-4-羟基苯基）丙酸]季戊四醇酯（AO-1010）,然后将其加入到XNBR基体中制备出了不同的XNBR/AO-2246和XNBR/AO-1010二元有机杂化材料,并分别探讨了成型条件和小分子结构两个因素对二元有机杂化材料阻尼性能的影响。为了探讨成型条件对二元有机杂化材料的阻尼性能的影响,本文采用不同的成型条件分别制备出了未热压和热压XNBR/AO-2246样品,并对其结构及阻尼性能进行了研究。研究结果表明,在未热压XNBR/AO-2246样品中,大部分AO-2246分子以晶体颗粒的形式存在,AO-2246只起到了类似无机填料的作用导致共混体系的tanδ值比纯XNBR基体还低。而在热压XNBR/AO-2246样品中,由于热压淬火过程中两组分间形成了大量较强的分子间氢键作用而发生杂化,形成了一种特殊的形态结构。AO-2246不仅能使共混体系的单一tanδ峰高度明显增大（最高达3.5）,并且可通过调节AO-2246含量使tanδ峰处于不同的温度范围（从-21℃到23℃）以满足不同的使用需求,从而得到了一种新型XNBR基高阻尼复合材料。为了进一步探讨小分子的结构对二元有机杂化材料的阻尼性能的影响,本文还制备出了热压的XNBR/AO-1010样品,并将其阻尼性能与热压的XNBR/AO-2246样品进行对比分析。研究结果表明,在XNBR/AO-1010杂化材料中,由于AO-1010和XNBR间形成的分子间氢键作用较弱,大多数的AO-1010分子都以结晶颗粒或集聚体的形式分散在XNBR基体中,从而呈现出一种以XNBR富集相为海,AO-1010富集相为岛的“海-岛”形态结构。因此,除XNBR的tanδ峰外,出现了一个新的tanδ峰。由于主要由AO-1010晶体构成的AO-1010富集相起到了类似无机填料的作用,因而导致XNBR的tanδ峰高度大幅降低,但两峰之间的高度随AO-1010含量的增加而有所提高,呈现出较宽的有效阻尼温域。通过研究,本文得出这样一个结论:对二元有机杂化材料而言,成型条件或小分子结构的不同均会导致体系中两组分间形成的分子间氢键的数目和种类的不同,从而影响小分子在基体聚合物中的分散状态,最终对体系的动态力学性能产生不同的影响。2.三元有机杂化阻尼材料的制备及有机杂化材料阻尼性能稳定性研究在对两个二元体系进行分析对比的基础上,本文将AO-2246和AO-1010同时加入到XNBR基体中制得多种不同的三元XNBR/AO-2246/AO-1010杂化体系,进一步探讨了两种小分子对XNBR基体的阻尼性能的协同作用及其机理。对不同的三元XNBR/AO-2246/AO-1010体系DMA测试结果表明,向XNBR/AO-2246中加入少量AO-1010（<20 wt%）会使体系的tanδ峰高度进一步提高,同时也使tanδ峰对应的温度大幅提高,从而证实了AO-2246和AO-1010对提高XNBR的阻尼性能具有一定的协同效应。此外,研究结果还表明可通过改变AO-1010添加量或XNBR/AO-2246的质量比来对三元XNBR/AO-2246/AO-1010体系的tanδ峰高度和位置加以调控,从而得到一系列满足实际应用需求的高性能阻尼材料。为了对制备出的有机杂化阻尼材料在实际应用中的性能稳定性加以预测和了解,本文对XNBR/AO-2246二元杂化体系样品在室温下长期放置老化或不同温度下进行退火处理后的阻尼性能进行了测试。通过比较老化或退火处理前后不同XNBR/AO-2246杂化材料阻尼性能的变化对该体系的阻尼稳定性进行了深入研究。研究结果表明,经老化或退火处理后,在XNBR和AO-2246间形成的较强的分子间氢键作用的消失会导致AO-2246发生再聚集和结晶行为,从而导致杂化材料的tanδ峰高度大幅降低,几乎完全丧失了刚制备时具有的高阻尼性能。这与类似的高分子/小分子共混体系中发现的结果一致。但是,研究还发现,在XNBR/AO-2246体系中存在可逆的分子间氢键作用,老化后的XNBR/AO-2246样品在高于AO-2246熔点的温度下经过再加热处理后,其tanδ峰高度会再次上升回复到老化前的tanδ值,甚至超过未老化的样品。XNBR/AO-2246杂化材料阻尼性能的这种热可逆效应主要是由于分子间氢键的再次形成对AO-2246分子的结晶行为产生一定的抑制作用引起的。因此,XNBR/AO-2246杂化材料可被用作新型热可循环橡胶阻尼材料。此外,本文在对三元XNBR/AO-2246/AO-1010杂化体系在等温退火过程中的阻尼性能稳定性进行研究后发现,向XNBR/AO-2246体系中加入少量AO-1010后会对AO-2246的结晶行为产生一定的抑制作用,从而使体系的阻尼性能稳定性有所提高。因此,可通过改变三元XNBR/AO-2246/AO-1010杂化体系的组成设计出一种新型的具有较高的阻尼峰且阻尼峰位置可调控,并且具有较好的阻尼性能稳定性的高性能阻尼材料。3.纤维增强和有机杂化相结合制备高性能阻尼材料针对XNBR/AO-2246有机杂化阻尼材料模量较低的缺陷,本文试图将纤维增强技术和有机杂化改性新方法相结合,制备出一种兼具较高模量和较好阻尼性能的高性能阻尼材料。在对芳纶浆粕（KP）和短碳纤维（SCF）与XNBR基体的添加效应进行比较后,本文最终选用SCF作为增强纤维,将其与AO-2246的杂化效应相结合,制备出了一系列三元XNBR/SCF（90/10）/AO-2246和XNBR/AO-2246（50/50）/SCF体系样品,并对其动态力学性能进行了研究。研究结果表明,向二元XNBR/SCF（90/10）体系中加入AO-2246后,可使体系在保持较高模量的同时,其阻尼峰高度获得较大幅度的提高,同时其阻尼峰位置也可通过改变AO-2246的含量加以调控以满足不同的实际需求,从而获得了一种兼具较高模量和较好阻尼性能的高性能阻尼材料。向二元XNBR/AO-2246（50/50）体系中加入一定量的SCF后得到的三元XNBR/AO-2246（50/50）/SCF体系尽管其tanδ峰高度有所下降,但tanδ_max值仍大于2.5,明显高于一般的阻尼材料。在保持较高阻尼的同时,体系的模量由于SCF的增强效应而大幅提高,从而得到了一种兼具较好阻尼性能和较高模量的高性能阻尼材料。这些结果证实了通过采用将有机杂化和纤维增强相结合的方法,可制备出一种新型的兼具高模量和高阻尼且阻尼峰位置可调控的高性能阻尼材料。因此,将纤维增强和有机杂化相结合的方法可看作是一种制备具有较大的工程应用价值的高性能阻尼材料的新方法。更多还原

【Abstract】 With the rapid development of modern industry,vibration and noise pollution is becoming more and more serious.From an environmental protection point of view, damping materials that can reduce the vibration and noise significantly should be adopted in many cases.Polymeric damping materials are a type of newly developed materials,which can absorb vibration energy due to the characteristic viscoelastic properties of polymers.They can dissipate mechanical or acoustic energy as heat,thus to decrease the amplitude or energy of vibration.Therefore,polymeric damping materials have been widely used in numerous fields such as automobiles,industrial machinery,skyscrapers,household appliances,precision instruments,appliance industries,military equipment,etc.The development of high technology brings higher and higher requirements on damping materials and each field needs more damping materials with broad temperature region,high performance and intelligence.However, most of the damping materials are not satisfied due to their poor comprehensive properties,in particular,they can’t possess both good damping and high strength at the same time.Thus,to develop damping materials with excellent comprehensive properties is extremely important.Under such a background,after comparing the advantages and disadvantages of various damping modification methods,we finally choose the recently developed organic hybrid damping modification method,through which organic hybrids with high-performance damping properties can be obtained by adding functional organic small molecules into polar polymers.Based on this novel design concept,the carboxylated nitrile rubber（XNBR） with larger polarity and good damping property was firstly chose as the matrix polymer,and selected functional organic small molecules were added into it to obtain organic hybrids with high damping factor.Then the comprehensive properties of the obtained organic hybrids were further improved by different ways to develop a series of high-performance damping material with better engineering application values.The damping mechanism of prepared materials were further discussed by using a combination of several analysis and testing means,such as dynamic mechanical thermal analysis （DMA）,differential scanning thermal analysis（DSC）,Fourier transform infrared spectroscopy（FT-IR） analysis,scanning electron microscopy（SEM） observation etc. to provide some theoretical reference for future research in this field.The main research contents and relevant research conclusions of this paper are as follows:1.Preparation and damping properties of binary organic hybrid damping materialsIn this paper,in order to prepare organic hybrid damping materials with high damping factor,two different functional organic small molecules 2,2’-methylenebis（6-tert-butyl-4-methylphenol）（AO-2246） and Pentaerythrityltetrakis -[β-（3,5-di-tert-butyl-4-hydroxyphenyl）-propionate]（AO-1010） were screened out through some theoretical analysis and experimental tests.Then different binary XNBR/AO-2246 and XNBR/AO-1010 organic hybrid materials were thus obtained by adding them into XNBR matrix.The influence of molding condition and chemical structure of small molecules on the damping properties of binary organic hybrid material were discussed respectively.In order to discuss the influence of molding condition on the damping properties of binary organic hybrid material,unpressed and pressed XNBR/AO-2246 samples were prepared by using different molding conditions and correlations between the microstructure and damping properties of unpressed and pressed XNBR/AO-2246 samples were studied.Results showed that in the unpressed system,most of the AO-2246 molecules existed in the form of crystalline particles.They only acted like inorganic fillers thus decreased the loss tangent（tanδ） peak height of the blend system remarkably to a value lower than that of pure XNBR.Whereas,in the pressed system,AO-2246 were hybridized with XNBR due to the formation of large amounts of hydrogen bonds between them during the hot-pressing and quenching process,thus a special flower-like morphology structure were formed.The addition of AO-2246 can not only increase the tanδpeak height of the blend system significantly up to 3.5 but also shift the tanδpeak position from -21℃to 23℃by adjusting the AO-2246 content.Thus,a new type of XNBR-based high damping composite was obtained.In order to further discuss the chemical structure of small molecules on the damping properties of binary organic hybrid material,pressed XNBR/AO-1010 samples were also prepared and compared with pressed XNBR/AO-2246 samples. Results showed that in the XNBR/AO-1010 hybrid system,most of the AO-1010 molecules dispersed in the XNBR matrix in the form of crystal particles or aggregates and the system exhibited a sea（XNBR-rich matrix）-island（AO-1010-rich domain） morphology due to weak interaction between AO-1010 and XNBR.As a result,a new tanδpeak appeared besides that of XNBR.The AO-1010-rich domain,which was mainly composed of AO-1010 crystals,seemed to act like inorganic fillers thus decreased the tanδpeak of XNBR significantly.However,the tanδvalue between the two tanδpeaks increased gradually with increasing AO-1010 content,showing a broader efficient damping temperature region.Thus,we came to the conclusion that for binary organic hybrid material,different molding condition or chemical structure of small molecules leaded to differences in the number or type of the intermolecular hydrogen bonds between the two components,thus leaded to different dispersion state of small molecules in the matrix and finally resulted in different additive effects on damping properties of binary systems.2.Preparation of ternary organic hybrid damping materials and studies on the damping stability of organic hybrid systemsBased on the analysis and comparison of two binary systems,AO-2246 and AO-1010 were added into XNBR matrix at same time,thus various ternary XNBR/AO-2246/AO-1010 hybrid systems were prepared to further discuss the synergistic effect of AO-1010 and AO-2246 on improving the damping property of XNBR.DMA measurements were carried out on various XNBR/AO-2246/AO-1010 ternary hybrids,results showed that the addition of a small amount of AO-1010（less than 20 wt%） into XNBR/AO-2246 hybrid leaded to not only a significant increase of the tanδpeak height but also a notable enhancement of the tanδpeak temperature, confirming that AO-1010 and AO-2246 indeed have a synergistic effect on enhancing the damping property of XNBR.Besides,it was also showed that the tanδpeak height and its position of ternary XNBR/AO-2246/AO-1010 hybrids could be controlled by varying AO-1010 content or XNBR/AO-2246 weight ratio.Thus,a series of high-performance damping materials with both high damping peak and controllable peak position suitable for different practical requirements were obtained.In order to get some information about the stability of the damping properties of prepared organic hybrid damping materials in practical applications,measurements were carried out on the damping properties of XNBR/AO-2246 hybrids which were aged in room temperature for a long time or annealed at different temperature in this paper.The damping stability of XNBR/AO-2246 hybrids was studied by comparing the changes of their damping properties before and after ageing or annealing.Results showed that after ageing or annealing treatment,the disappearance of strong intermolecular interactions between XNBR and AO-2246 leaded to the reaggregation and crystallization behavior of AO-2246.Thus the tanδpeak height of the hybrids decreased sharply and their high damping properties were nearly bankrupt.This is in accordance with the results found in similar polymer/small molecule blend systems. Nevertheless,it was also found that after reheating,the tanδpeak height of aged samples increased again and reverted to a value as high as even higher than that of the unaged samples due to the existence of reversible intermolecular hydrogen bonding interactions in XNBR/AO-2246 hybrid system.Such heat-reversible effect of the damping properties of XNBR/AO-2246 hybrids was attributed to bafflement of the reaggregation and crystallization behaviors of AO-2246 molecules by the recombination of the strong intermolecular hydrogen bonds between XNBR and AO-2246 molecules.Thus,XNBR/AO-2246 hybrids can be used as a new type of thermally recycling rubbers.Furthermore,studies on the damping stability of ternary XNBR/AO-2246/AO-1010 hybrid system during annealing process revealed that the addition of a small amount of AO-1010 into XNBR/AO-2246 hybrids obstructed the crystallization behavior of AO-2246 to some extent and finally improved the damping stability.Thus,a series of XNBR-based high-performance damping materials with high damping peak and controllable peak position as well as better damping stability can be designed by changing the composition of ternary XNBR/AO-2246/AO-1010 hybrid system.3.Preparation of high-performance damping materials by combination of fiber reinforcement and organic hybridizationAs to the low-modulus limitation of XNBR/AO-2246 organic hybrids,combination of fiber reinforcement and organic hybridization was adopted in order to develop a high-performance damping material with both high modulus and good damping property.After comparing the additive effects of Kevlar pulp（KP） and short carbon fiber（SCF） on the damping property of XNBR matrix,we finally selected SCF as the reinforcement fiber and combined its reinforcement effect with the hybridization effect of AO-2246.Thus,a series of ternary XNBR/SCF（90/10）/AO-2246 and XNBR/AO-2246（50/50）/SCF hybrid samples were prepared and measurements were made on their dynamic mechanical properties.Results showed that by the incorporation of AO-2246 into binary XNBR/SCF（90/10） system,the tanδpeak height increased remarkably while maintained a high modulus,at the same time,the tanδpeak position could be controlled by varying AO-2246 content to meet different practical requirements.Thus,a type of high-performance damping materials with both high modulus and good damping properties were obtained by adding AO-2246 into binary XNBR/SCF（90/10） system.It was also showed that by the introduction of SCF into binary XNBR/AO-2246（50/50） system,although the tanδpeak height was decreased to some extent,the tanδ_max value was maintained above 2.5,which was still much higher than that of most SFRC materials.While maintaining such a high damping factor,the modulus of ternary XNBR/AO-2246（50/50）/SCF system was improved significantly due to the reinforcement effect of SCF.Thus,a type of high-performance damping materials with both good damping properties and high modulus were obtained by adding SCF into XNBR/AO-2246 organic hybrids.These results confirm that a new type of high-performance damping material possessing both high modulus and high damping peak with controllable peak position can be obtained by combination of fiber reinforcement and organic hybridization. Therefore,combination of fiber reinforcement and organic hybridization can be considered to be a new way of developing high-performance damping materials with better engineering application values.更多还原