汽车顶棚用轻质GMT吸音性能的研究

研究了轻质玻璃纤维毡增强热塑性复合材料(GMT)板材的面密度、成型厚度、透气率以及GMT汽车内饰顶棚与钣金间隙4个因素与顶棚吸音性能的关系。结果表明,GMT汽车内饰顶棚的吸音系数受GMT板材面密度的影响不大,但随成型厚度的增加而增大;高透气率的顶棚的吸音系数在高频区最大;增加GMT汽车内饰顶棚与钣金之间的间隙可以显著提高顶棚在低频和中频区的吸音系数。     

陶瓷废料制备的吸音材料吸音性能影响因素的分析

随着社会的发展和生活水平的提高，社会对吸声材料的需求量呈迅猛增长之势，同时也对吸音材料的性能提出了更高更多的要求。吸音材料必须实现从过去单一吸音功能向高吸音性、装饰性、经济性和环保性等多功能转变。本文以陶瓷抛光砖废料制备的陶粒、水泥、珍珠岩和粉煤灰为主要原料，辅以造孔剂和防水剂等添加剂，采用一般混凝土的成型方法研制成一种新型无纤维多孔吸音材料，通过试验分析了材料的容重、厚度、孔隙率等因素对这种吸音材料吸音性能的影响。     

汽车隔音垫用聚氨酯软质高回弹泡沫的吸音性能研究

通过驻波管法测试不同隔音垫聚氨酯软质高回弹泡沫的吸声系数,结合显微镜对泡沫的力学特性和形态进行观察和分析。研究结果表明,泡沫在低频区的吸声系数随厚度的增加而提高,而在高频区则有所减弱;泡沫的吸声系数随密度增加而提高;泡孔形态对泡沫的吸声性能有显著影响,细密而均一的泡孔有利于声能的吸收;不同异氰酸酯由于反应性和结构上的差异,泡沫也表现出不同的吸声特性;高压发泡生产的泡沫峰值吸声频率稍向高频区移动,复合乙烯–醋酸乙烯共聚弹性体（EVA）后泡沫的峰值吸声频率稍向低频区移动。     

一步法顶棚骨架成型胶粘剂的施胶工艺对顶棚成型的影响

由于聚氨酯无溶剂环保胶粘剂作为汽车顶棚骨架成型胶粘剂的推广应用,汽车顶棚湿法制造成型法克服了环保的枷锁而受到顶棚制造商的青睐,汽车顶棚湿法制造工艺其本质就是汽车顶棚骨架成型胶粘剂的施胶工艺.本文通过研究顶棚湿法制造工艺一步成型法成型过程中喷水量/喷胶量、模压温度、模压压力、喷胶喷水后的放置时间对顶棚出模硬度、弯曲强度的...     

废旧汽车顶棚材料热解特性及动力学

利用热最-红外联用技术,研究了氮气气氛下报废汽车顶棚材料在30～900℃的热解行为,分析了其热解过程的热解反应特性以及动力学.汽车顶棚材料的组成为含有较高比重无机填料的聚氨酯泡沫塑料.不同热解温度下挥发份的红外谱图分析表明,热解产物含有烷烃、烯烃、醇、胺等.三个热解阶段发生的热解反应分别是聚氨酯中氨基甲酸酯基的热分解、...     

快速固化汽车顶棚胶的研制

以二丁基二月桂酸锡为促进剂,多异氰酸酯PAPI与聚醚220反应制得单组分溶剂型聚氨酯胶黏剂,用于汽车内饰材料与车体的粘接.首先考察了PAPI用量、促进剂用量对粘接性能的影响,试验结果表明PAPI及促进剂用量较高时粘接效果好.探讨了不同处理方法对胶黏剂黏度及贮存性能的影响,发现加入苯甲酰氯后胶黏剂的黏度低、贮存过程中黏度变化小.通过对胶黏剂贮存期、适用期的考察表明其贮存稳定、工艺性能好,适合流水线喷涂作业.     

工艺条件对硬质聚氨酯泡沫泡孔结构和性能的影响

选取质量填充系数、模温、料温和搅拌速度4个工艺因素,对一种硬质聚氨酯泡沫的发泡过程进行4因素3水平的正交试验。通过对实验数据的分析,讨论了工艺条件对这种硬质聚氨酯泡沫泡孔结构和性能的影响。结果表明,提高模温,能够有效改善泡沫的整体密度、生长方向的密度和泡孔的均匀性。在40℃的模具温度,2000 r/min的搅拌速度,2.0倍质量填充系数时,硬质聚氨酯泡沫密度和泡孔均匀性最好;随着质量填充系数增加,力学性能提高。     

用正交试验研究影响环氧摩擦学性能的因素

利用正交试验研究了影响环氧树脂摩擦磨损性能的因素,通过直观分析法对试验结果进行了分析,结果显示对摩擦系数和磨损率而言,载荷和表面粗糙度都是显著的影响因素。用电镜对不同粗糙度下的磨损面形貌进行了观察,结果表明随粗糙度增加材料的磨损机理由疲劳磨损变为磨粒磨损。     

双组分水性聚氨酯汽车面漆的制备与性能研究

介绍了配制双组分聚氨酯涂料的工艺过程,并通过一系列的对比实验,考察了树脂、固化剂、n—NCO/n—OH配比、PVC和助剂对涂膜性能的影响,以及涂料的适用期。试验结果表明:羟基丙烯酸树脂Bayhydrol A XP 2695和固化剂Bayhydur XP 2655配用,n—NCO/n—OH为1.4,PVC为15%,润湿分散剂TG270和TG755配用,流平剂TG700和BYK380N配用,可获得综合性能优异的涂膜,满足汽车面漆的性能要求;涂料的适用期约为4 h。     

聚醚型聚氨酯性能的影响因素

采用不同种类的聚醚多元醇、二异氰酸酯和扩链剂为原料合成聚氨酯,讨论了聚醚多元醇的相对分子质量、二异氰酸酯的结构、软硬段比例、二异氰酸酯指数、扩链剂种类及用量对聚氨酯性能的影响。结果表明：采用高相对分子质量的聚醚,聚氨酯的定伸强度、拉伸强度和撕裂强度下降,断裂伸长率提高;聚氨酯的性能随硬段含量的增加而提高;异氰酸酯指数控制在1.01~1.03左右;扩链剂链长越短,聚氨酯的微相分离程度和力学性能越好;聚氨酯性能随1、4-丁二醇用量的增加而提高,达到一定用量时反而下降。     

聚硅氧烷改性聚氨酯涂层吸声性能研究

研究了聚硅氧烷改性聚氨酯涂层的吸声性能,研究结果表明,填料种类、结构、含量以及空腔结构会对涂层体系的吸声性能产生不同程度的影响。     

Finite Element Solution for Dynamic Mechanical Parameter Influence on Underwater Sound Absorption of Polyurethane-Based Composite

Underwater noise pollution, mainly emitted by shipping and ocean infrastructure development of human activities, has produced severe environmental impacts on marine species and seabed habitats. In recent years, a polyurethane-based (PU-based) composite with excellent damping performance has been increasingly utilized as underwater sound absorption material by attaching it to equipment surfaces. As one of the key parameters of damping materials, dynamic mechanical parameters are of vital importance to evaluating the viscoelastic damping property and thus influencing the sound absorption performance. Nevertheless, lots of researchers have not checked thoroughly the relationship and the mechanism of the material dynamic mechanical parameters and its sound absorption performance. In this work, a finite element model was fabricated and verified effectively using acoustic pulse tube tests to investigate the aforementioned issues. The influence of the dynamic mechanical parameters on underwater sound absorption performance was systematically studied with the frequency domain to reveal the mechanism and the relationship between damping properties and the sound absorption of the PU-based composite. The results indicate that the internal friction of the molecular segments and the structure stiffness were the two main contributors of the PU-based composite’s consumption of sound energy, and the sound absorption peak and the sound absorption coefficient could be clearly changed by adjusting the dynamic mechanical parameters of the composite. This study will provide helpful guidance to develop the fabrication and engineering applications of the PU-based composite with outstanding underwater sound absorption performance.     

碱矿渣泡沫混凝土的吸声性能试验研究

为了研究开发一种新型的绿色低碳吸声材料,以化学发泡法制备碱矿渣泡沫混凝土试样,通过实验分析了材料容重、碱当量和纤维掺量对碱矿渣泡沫混凝土的抗压强度、吸水率、吸声性能的影响.结果表明:随着容重的增加,材料的抗压强度提高,吸水率下降,低频吸声性能提高,而高频吸声性能下降;随着碱当量的提高,材料的抗压强度提高,吸水率先降低后提高,在50Hz到1600Hz频段内的吸声系数有一定提高;适宜掺量的纤维会提高材料的抗压强度,掺入过多对强度发展不利,同时纤维的掺入会提高材料的高频吸声性能.     

粉煤灰对超轻发泡混凝土孔结构及吸声性能的影响

以化学发泡法制备泡沫混凝土试样,并结合图像分析软件(Image-Proplus 6.0)测得了不同粉煤灰掺量时试样孔隙率、平均孔径和孔径分布等孔结构参数,并研究了粉煤灰掺量对试样28 d抗压强度和吸声性能的影响.结果表明:随着粉煤灰掺量的增大,试样孔隙率和平均孔径逐渐减小,28 d抗压强度先增加后降低,试样的吸声性能有一定程度的提高.     

发泡工艺和发泡剂用量对丁基橡胶发泡材料阻尼吸声性能的影响

研究硫化时间、硫化温度以及偶氮二甲酰胺(AC)发泡剂用量对丁基橡胶发泡材料阻尼性能和吸声性能的影响。结果表明:在165℃下硫化30 min时,发泡丁基橡胶有最佳的阻尼性能;在160℃下硫化50 min时,发泡丁基橡胶有最佳的吸声性能。随着发泡剂AC的加入,丁基橡胶发泡材料的阻尼性能和吸声性能均有明显提升。当发泡剂AC用量较小时,材料阻尼性能较好;当发泡剂AC用量为6份时,材料吸声性能较好。     

填料对吸声涂层材料性能的影响

用自制改性的硅橡胶材料作吸声涂料基料,研究了不同填料对硅橡胶材料吸声性能的影响。结果表明：石墨、空心微粉能够改善硅橡胶吸声性能;其中。石墨能明显提高硅橡胶材料平均吸声系数,且平均吸声系数随石墨用量的增大而增大;石墨用量以20份为宜。     

Investigation on Sound Absorption Function and Mechanical Behavior of Polycarbonate/Nanosilica-based Nanocomposites

The present study reports the morphological, mechanical, and sound absorption properties of polycarbonate-based nanocomposites containing nanosilica (0.3 and 0.6?wt%). To this end, the specimens were prepared by melt mixing in a twin-screw extruder. The scanning electron microscopy was also used to ensure the well distribution of nanosilica in the polymeric matrix. The mechanical properties were investigated by tensile, flexural strength, Izod impact, and hardness tests. At the end, sound absorption coefficient of the specimens was checked by standing wave sound impedance tube method in the frequency range of 250–6,300?Hz. The results showed that only a small amount of nanosilica could improve the mechanical properties of specimens. However, the sound absorption function of specimens had a gradual improvement by increasing nanosilica content. Tensile modulus and strength at yield of the nanocomposite specimens were higher than that of the neat polycarbonate. On the contrary, a decrease in elongation at break was reported, which was attributed to the reduced mobility of the polymer chains due to the presence of nanoparticles. The same behavior was observed in the test results of Izod impact strength of nanocomposites so that adding nanosilica with the wt% of 0.6 to the neat polycarbonate, the impact strength improved by only 5.3%. According to the findings, polycarbonate composites with 0.3?wt% nano-silica, in addition to strengthening the mechanical properties (tensile modulus, flexural strength, and stiffness), could improve the acoustic characteristics of the specimens in low and mid frequencies. The findings also revealed that the performance of pure polycarbonate and 6?wt% nanosilica polycarbonate in upper frequency range was higher and approximately the same as that for 3?wt% nanosilica polycarbonate.     

纳米颗粒强化氨水鼓泡吸收性能的机理与影响因素

基于Danckwerts的界面更新模型和Langevin方程,分析了纳米颗粒对氨水鼓泡吸收性能影响的非均相膜传递和液相内传递过程,初步解释了纳米颗粒强化氨水鼓泡吸收性能的机理.认为纳米颗粒对氨水鼓泡吸收的强化过程包括液相强化和界面强化两个同时进行的子过程,而对于界面传递,由于纳米颗粒引起的Marangoni对流,使其强...     

硝酸铵吸湿点测定方法的改进及影响因素

吸湿点是硝酸铵在用作固体推进剂时的重要指标之一。通过实验对吸湿处理的方法进行了改进,并从温度、称样量及样品表面积3个方面对硝酸铵吸湿点测定的影响进行了分析。依据实验得出的数据,将吸湿处理的方法改进为在25℃的恒温环境中、90%的相对湿度下吸湿3 h。在影响因素中,温度对其影响最明显;称样量对吸湿点的测定影响比较小,但使称样量尽量接近会减小平行差;表面积对吸湿点测定的影响较大。