磁场取向镀镍碳纳米管/聚氨酯复合泡沫材料的制备及性能

在磁场作用下通过一步法原位聚合制备了磁场取向镀镍多壁碳纳米管/聚氨酯复合泡沫材料.通过透射电镜、扫描电镜等表征了泡沫材料的结构,并测试了材料的压缩性能和吸声性能.结果表明:镀镍碳纳米管可使聚氨酯泡沫材料的泡孔更均匀.在磁场作用下,镀镍碳纳米管取向能显著提高材料的压缩强度,当碳纳米管的质量分数为1.0%时,其压缩强度为纯PU泡沫材料的3倍.同时,取向镀镍碳纳米管/PU复合泡沫材料的吸声性能也得到了进一步提高.     

一种新型吸声材料的结构设计及其吸声性能研究

以聚醚多元醇和异氰酸酯为原料,通过一步法制备了聚氨酯泡沫(PU),将PU与微穿孔板(MPP)结合起来,制备了一种新型层状吸声结构。分别研究了穿孔率、空腔深度、材质及MPP厚度对其吸声性能的影响。结果表明:所设计的新型层状吸声结构具有良好的吸声性能,所设计的吸声结构在空腔厚度为20mm时具有最佳吸声性能。     

制备工艺对聚氨酯酰亚胺泡沫性能的影响

以均苯四甲酸二酐(PMDA)、多苯基多亚甲基多异氰酸酯(PAPI)、聚醚多元醇为主要原料,分别采用聚酰亚胺(PI)预聚法、聚氨酯(PU)预聚法和一步法制备聚氨酯酰亚胺泡沫,从微观形貌、力学性能、热稳定性能以及阻燃性能方面对上述3种制备工艺进行对比和评估。实验结果表明,采用一步法制备PUI泡沫时,PU链段和PI链段同时增长,容易造成泡孔缺陷,导致泡沫的力学性能较差;在采用PU预聚法制备的PUI泡沫中,PU链段含量较高,因此,泡孔孔径分布较宽且平均泡孔直径较大,对应的热稳定性和阻燃性能较差;采用PI预聚法制备的PUI泡沫的泡孔孔径分布窄且平均泡孔直径较小,对应的压缩性能、热稳定性以及阻燃性能均达到最佳。     

吸声泡沫陶瓷研究进展

吸声泡沫陶瓷作为一种新型的吸声材料在噪声控制领域展现出优异的性能和广泛的应用潜力。简要介绍了泡沫陶瓷的吸声降噪机理,陈述了近年来吸声泡沫陶瓷的制备方法以及探讨影响吸声性能的因素,并展望了泡沫陶瓷吸声材料的研究发展趋势。     

EVA发泡材料吸声性能研究

借助阻抗管法测试了自制的EVA(乙烯–醋酸乙烯共聚物)泡沫材料的吸声系数,探讨了影响EVA泡沫吸声性能的因素。结果表明:不同的发泡温度下,EVA泡沫的吸声系数不同,其中180℃下发泡的材料吸声性能最佳;泡沫的吸声系数随泡沫厚度的增加而增加,但超过30 mm后吸声系数趋于平稳;连续通孔结构泡沫的吸声性能要显著优于闭孔泡沫的;材料的吸声系数随测试样片直径增加呈现先增加后减小的变化趋势。     

STG/IP稀释比对STG/PU复合材料低速抗冲击性能的影响

研究了剪切增稠凝胶(STG)不同稀释比对STG/聚氨酯(PU)复合材料低速抗冲击性能的影响。按照V(STG)∶V(异丙醇)=1∶1、1∶2、1∶3的比例进行稀释,制备3组STG/PU材料样品,一组不加STG的纯PU材料作为对照,测试4组材料的低速抗冲击性能。并通过扫描电镜观察复合前后泡沫的微观形貌。结果表明,STG均匀地附着到PU泡沫上;STG大大提高了泡沫材料的抗冲击性能,且性能跟稀释比有关。     

低密度PU发泡板在汽车内饰顶棚中应用及研究

介绍了汽车顶棚的结构组成和基本性能要求,并研制出一种全新的22kg/m3的低密度PU板。通过实验比较结构不同的汽车顶棚间在性能方面的差异,低密度PU发泡板的吸音降噪、储存时间、刚性强度等性能较原先聚氨酯(PU)材料有明显提升。     

聚氨酯泡沫材料吸声频率特性研究

聚氨酯泡沫材料是目前应用较多的一种多孔性吸声材料，其吸声性能不仅与泡孔结构等材料本身性质有关，还与吸声结构和实际使用安装状态有关。本研究主要研讨了研制聚氨酯泡沫及其吸声结构板材的吸声频率特性。研究结果表明，（1）研制聚氨酯泡沫吸声材料具有优良的吸声性能，50mm厚时所测得100-5000HZ范围内的驻波管法平均吸声系数可达到0．51；（2）利用共振吸声原理来组装聚氨酯泡沫芯吸声结构可有效地调节材料的吸声频率特性；（3）在聚氨酯泡沫芯吸声结构中，将泡沫芯做成狭缝结构和尖劈结构，还可进一步拓展其吸声频率特性。     

EPR改性PVC泡沫材料吸声性能的研究

研究了EPR用量、发泡剂AC用量、泡沫材料厚度和发泡温度等因素对EPR改性PVC泡沫材料吸声性能的影响。结果表明,EPR可显改善PVC泡沫材料吸声性能,随着EPR用量的增大,泡沫材料低频吸声性能得到显提高,而高频吸声性能略有下降;发泡剂AC用量的增大可明显改善泡沫材料的中高频吸声性能,低频吸声性能有所降低;材料厚度的增大可提高全频段吸声性能,低频吸声性能的提高更为显;随着发泡温度的升高,低频吸声性能提高,中高频吸声性能则有所下降。     

有机掺杂修饰对泡沫陶瓷吸声性能的影响机理

综述了吸声材料的研究、应用发展趋势,平均吸声系数较低是制约泡沫陶瓷在吸声降噪工程领域应用的关键因素.研究了泡沫材料吸声机理,提出对泡沫陶瓷进行有机材料掺杂修饰,增强粘滞吸收、弛豫吸收和热传导作用,提高对声能的吸收及转化效率以提高吸系数.     

Experimentation,simulation, and statistical analysis of nanofillers reinforced bio-based polyurethane foam for acoustical applications

This research aims to develop bio-based polyurethane foam (PU) with nanofillers to absorb sound energy across a broad frequency range and compare experimental results to those from simulation and optimization. PVDF (Polyvinylidene fluoride), MgO (Magnesium oxide), and Ni (Nickel) nanofillers were incorporated into bio-based PU through absorption and hydrothermal reduction technique, which includes mechanical stirring, compressing, heating, and evaporating. To determine the weight percentages of nanofillers, the design of the experimental approach was utilized. As per ASTM standard E 1050-12, the bio-based PU foam composite's sound absorption coefficient (SAC) was assessed using an impedance tube setup. Response Surface Methodology was utilized to estimate optimum sample weight percentages using a central composite design (CCD) with weight percentages of the three nanofillers as input and the noise reduction coefficient (NRC) as response output. According to the CCD results, the combination of 15 wt% PVDF, 10 wt% MgO, and 5 wt% Ni shows the highest NRC value of 0.66. Then, a confirmation sample was prepared, and the NRC was calculated. The NRC achieved for the confirmation sample was 0.62. SAC simulation results are contrasted with experimental data using COMSOL Multiphysics 5.5. The confirmation sample's average sound pressure level (SPL) reduction ranges from 2 to 29 dB, according to the SPL plot. The conclusion shows that bio-based composite foam may be an excellent material for absorbing sound in vehicles and aircraft and reducing industrial noise.     

Polyurethane/poly(vinylidene fluoride)/MWCNT composite foam for broadband airborne sound absorption

A polyurethane/poly(vinylidene fluoride)/multi-walled carbon nanotubes (PU/PVDF/MWCNT) (83/15/2) composite foam was designed and fabricated. The foam exhibited high airborne sound absorption performance in a wide-frequency range. The sound absorption coefficient reached the value of 0.85 at 1 kHz, which is a significant improvement over PU foam. It was found that PVDF formed a separate immiscible phase and part of it was crystallized in a polar phase in the PU scaffold in the PU/PVDF/MWCNT composite, which could benefit the sound absorption performance by introducing interfacial damping and local piezoelectric damping effects. The introduction of the conductive MWCNT filament in the composite foam further improved sound absorption, possibly by facilitating the dissipation of the electrical charges generated from local piezoelectric effect and enhancing both the interfacial damping effect and local piezoelectric damping effect. With PU as the main ingredient, the fabrication scalability of the foam can be improved with significantly reduced material and production cost in comparison with PVDF foam. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47868.     

Development,characterization, and modeling of environmentally friendly open‐cell acoustic foams

This study shows the development of new polymeric open‐cell foams from polypropylene (PP) and polylactide (PLA) resins with a focus on sound absorption properties and modeling of these foams. The objective is to develop new environmentally friendly foams to replace the existing non‐recyclable Polyurethane foams are currently used for sound insulation in industry. Through this research, open‐cell foams of about 90% porosity were fabricated from PP and PLA. These resins were selected since PP is a recyclable thermoplastic polymer, and PLA is a bio‐based thermoplastic polymer made from renewable resources. Polyurethane (PU) foam which is currently used for sound absorption and noise control in industry was compared to the fabricated PP and PLA foams. As the first attempt to fabricate environmentally friendly acoustic foams, the resulting foam structures show improved properties as compared to the existing materials. The average absorption of PP and PLA foams fabricated is in the range of 0.42–0.55 which is comparable or even higher than the average absorption of PU foam. To better understand the effect of structural and material properties on sound absorption and further improve the acoustic performance of bio‐based foams, an analytical model based on Johnson–Champoux–Allard model was used to numerically simulate the acoustic performance of foams under study. POLYM. ENG. SCI., 2013. © 2013 Society of Plastics Engineers     

汽车用新型吸声材料——稻草秸秆板 吸声性能的测定

研究了用可再生资源稻草秸秆板替代汽车用吸声泡沫塑料。应用L₉(3⁴)正交试验研究了稻草秸秆长度、秸秆板密度、热压时间对秸秆板的吸声性能的影响,结果表明秸秆板密度是影响稻草秸秆板吸声系数的主要因素。通过测试发现相同厚度的稻草秸秆板平均吸声系数大于泡沫塑料,当用稻草秸秆板替代XMQ 6608客车原发动机隔声罩内的泡沫塑料时,新罩的降噪效果优于原罩,试验结果证明:轻质稻草秸秆板是能用作汽车吸声材料的。     

Mechanical,acoustic, and thermal performances of shear thickening fluid–filled rigid polyurethane foam composites: Effects of content of shear thickening fluid and particle size of silica

Shear thickening fluid (STF) features a rheological property, and rigid polyurethane (PU) foams feature low thermal conductivity and excellent acoustic insulation. In this study, an STF/PU rigid foam composite sandwich structure was designed using different contents (0, 0.5, 1, or 1.5 wt %) of STF that contained 14 nm, 40 nm, or 75 nm silicon dioxide (SiO₂). The effects of STF content and silica size on the cell structure, mechanical performance, acoustic absorption, and thermal performance of the STF/PU foam were explored. The test results show that STF/PU foam exhibited three characteristic acoustic absorption peaks, and the maximum acoustic absorption coefficient reached 0.841. STF addition increased compression, bending strength, and maximum acoustic coefficient, as well as initial mass loss temperature. STF-filled PU foam composites containing 14 nm and 40 nm SiO₂ had a mild rise in thermal insulation. The rigid STF/PU foam composites with a cell structure had the maximum thermal conductivity of 0.22 W m⁻¹ K⁻¹ and sound absorption coefficient of 0.841, which confirm that they are a good candidate for sound-absorbing energy conservation materials. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47359.     

三聚氰胺泡沫塑料在船艇机舱吸声降噪中的应用

针对噪声严重影响军用船艇战斗性,而船艇噪声主要来自机舱的实际情况,对某型军用船艇机舱进行了噪声测试及频谱分析,发现机舱噪声辐射的主要频段,计算了混响对机舱噪声的影响,制定了采用吸声材料降低机舱混响的降噪方案.通过研究驻波管实验法测试不同密度、不同厚度的三聚氰胺泡沫塑料的吸声系数,确定了三聚氰胺泡沫塑料的结构参数.按照设计方案实船安装了三聚氰胺泡沫塑料并进行噪声测试,其结果为机舱平均声压级降低了5.6 dB,达到设计要求.     

Influences of rice hull in polyurethane foam on its sound absorption characteristics

In this article, rice hull (RH) was used in the moulding of polyurethane (PU) foam system. The article analyzed the participation of RH in the chemical reaction of PU synthesis with Attenuated Total Reflection‐Fourier Transform Infrared spectroscopy method. Besides, the influence of RH on the formation of pore structure along with the acoustic performance such as sound impedance rate, acoustic reflection factor, sound absorption coefficient, and transmission loss of the products were studied with the Transfer Function Method. The results indicated that RH significantly influenced the uniformity of pore diameter in PU foam. As the content of RH increased, the sound absorption peak shifted toward lower frequency region. And the sound absorption coefficients increased till a threshold value of RH content. POLYM. COMPOS., 34:1847–1855, 2013. © 2013 Society of Plastics Engineers     

Nanofibers (PU and PAN) and nanoparticles (Nanoclay and MWNTs) simultaneous effects on polyurethane foam sound absorption

In this research, simultaneous effects of polyacrylonitrile (PAN) and polyurethane (PU) nanofibers, multi wall carbon nanotubes (MWNTs) and nanoclay incorporation on sound absorption behavior of polyurethane foam were studied. The most important parameters such as nanoparticles content, number and mass per unit area of nanofiber layers and foam thickness were chosen and their influences on sound absorption in a wide band of frequencies were investigated. Applying of both nanoparticles gave rise to considerable improvement in PU foam sound absorption, however in case of MWNTs more satisfied results were observed. Sound absorption tests of simultaneous incorporation of MWNTs and nanoclay showed that the optimized result can be obtained at moderate to high MWNTs percents (0.1–0.15 wt.%) and low percents of nanoclay (0.5 wt.%). On the other hand, by adding PAN or PU nanofiber layers within the PU foam structure, superior sound absorption was achieved. Upper sound absorption by increasing the numbers of nanofiber layers was obtained. Incorporation of PAN nanofiber layers showed a better effect at high mass per unit area (5 g/m²), however the higher sound absorption in case of PU nanofiber layers was observed at low mass per unit area (1 g/m²).     

聚氨酯材料在汽车顶棚的应用

介绍了汽车顶棚的结构组成、成型工艺及基本性能要求,通过测试比较不同结构顶棚之间的性能差异,重点论述聚氨酯发泡材料对汽车顶棚的隔热保温及吸音降噪效果.     

Sound absorption performance of a lightweight ceramic foam

Porous materials can be effective for sound absorption and noise reduction. A kind of lightweight cellular ceramic foam with bulk density of 0.38–0.56 g cm^-3 was successfully prepared by conventional molding with pore forming agent. The porosity is from 76.4% to 83.7% for the sample with relatively large pores (the average pore size: 5.3–5.6 mm), and from 74.1% to 81.1% for the sample with relatively small pores (the average pore size: 1.5–1.7 mm). The effects were investigated for processing parameters on the structure of samples, and for the pore size, sample thickness and porosity on the sound absorption performance of samples. The results show that the absorption performance of the ceramic foam product with relatively large pores may be superior to that with relatively small pores in the case of the approximately same porosity. The first absorption peak moves from a higher frequency to a lower frequency with the increase of sample thickness. When the porosity increases, the average sound absorption coefficient increases for all of the samples, and the first absorption peak moves from a higher frequency to a lower frequency for the sample with relatively large pores but does not change for that with relatively small pores.