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.     

新型含磷阻燃型桐油基聚氨酯硬泡的制备及性能表征

桐油与甘油在甲醇钠为催化剂的条件下发生醇解反应得到桐油醇解产物（GTO）,GTO经环氧化得到环氧化桐油醇解产物（EGTO）,EGTO与9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物（DOPO）发生开环反应生成新型含磷阻燃型桐油基多元醇（PTOP）。PTOP部分取代聚醚多元醇（PPG4110）与异氰酸酯及助剂反应,通过一步法制备聚氨酯硬泡（RPUF）。采用万能试验机、热导率测定仪、热重分析仪和锥形量热仪分别考察RPUF的力学性能、热稳定性和燃烧行为。结果表明：随着PTOP替代石油基多元醇的比率增大,RPUF的压缩强度、密度、热导率先增大后减小,热稳定性提高,极限氧指数（LOI）由18.1%提高至26.0%,而总放热量先减小后增大,这主要是由于PTOP结构中的DOPO基团具有阻燃作用而PTOP结构中含有的桐油基脂肪链易于燃烧且热释放量较大。以上结果表明PTOP部分取代PPG4110制备的RPUF具有良好的阻燃性能和热稳定性。     

Physical properties of garnet‐filled polyurethane foam composite

Garnet‐filled polyurethane foam composite was prepared by solvent‐free reaction. Density, hardness, and compression strength were measured to study its basic physical properties. Percent volume loss and arithmetical mean surface roughness were investigated as an abrasion property to determine its potentiality as an abrasive and establish a relationship between basic properties and abrasion properties. These properties were measured as functions of blowing agent content, and garnet was used as filler. The particle size of the garnet and the polyol mixing ratio were also changed to investigate the dependence of properties on formulation. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1336–1343, 2001     

A study to determine electromagnetic interference-shielding effectiveness on bio-based polyurethane foam reinforced with PVDF/MgO/Ni for emerging applications

The main objective of this study is to prepare nanoparticles-induced bio-based polyurethane foam to shield electromagnetic interference (EMI) radiation in the 8–12 GHz frequency range and compare the experimental result with optimization and simulation. Polyvinylidene fluoride (PVDF), magnesium oxide (MgO), and Nickel (Ni) nanoparticles were induced into bio-based PU (polyurethane) foam through absorption and hydrothermal reduction technique, which includes mechanical stirring, compressing, heating and evaporating. The design of experiment (DOE) methodology was used to find nanoparticle weight percentage (wt%). EMI shielding effectiveness of the bio-based PU foam composite was measured using Vector Network Analyzer (N5230A PNA-L). The weight percentages of the optimized sample were predicted using the response surface methodology (RSM), in which the central composite design (CCD) employed the weight percentages of the three nanoparticles as input and the results of the electromagnetic interference shielding effectiveness (EMI SE) experiment as the response output. The result from CCD showed that 3 wt% of PVDF, 10 wt% of MgO, and 1 wt% of Ni gave a maximum EMI SE of 27.78 dB. Then a confirmation sample was created for the same, and EMI SE was estimated empirically. The results obtained for the confirmation sample are 27.56 dB. Then, a scanning electron microscope image was taken for the confirmation sample to analyze nanoparticle-induced bio-based PU foam's structural properties. The SEM image with dxf format is imported into the radio frequency (RF) module to calculate the EMI SE through COMSOL Multiphysics. The simulated EMI SE for the confirmation sample was 25.1 dB.     

Properties of a novel inherently flame-retardant rigid polyurethane foam composite bearing imide and oxazolidinone

A novel inherently flame-retardant rigid polyurethane (PU) foam with imide and oxazolidinone was prepared by using 3,3′,4,4′-biphenyltetracarboxylic dianhydride (PTDA) and 9,10-dihydro-9-oxa-(10-glycidoxypropylene)-10-phosphap-henanthrene-10-oxide (e-DOPO) as reactive flame retardants. The physical and mechanical properties of the prepared PU foams were investigated. The compressive strength was improved to 0.22 MPa, the thermal conductivity decreased, and the density hardly changed. Thermogravimetric (TG) analysis and TG analysis coupled with Fourier transform infrared spectroscopy indicated that the PTDA and e-DOPO showed a small improvement in thermal properties. The fire behaviors were evaluated based on the limited oxygen index (LOI), cone-calorimetry experiment, and smoke-density test. The LOI of the PU foam with PTDA and e-DOPO reached 22.4%. The peak of heat release rate and total heat release decreased to 227.50 kW m⁻² and 11.27 MJ m⁻² from 281.28 kW m⁻² and 14.05 MJ m⁻², respectively. The morphologies of the PU foam and residues after the cone-calorimetry test were characterized by scanning electron microscopy. X-ray photoelectron spectroscopy analysis indicated that PTDA and e-DOPO lead to an increase in graphite in the residue and the formation of a better barrier to prevent burning by the condensed-phase mechanism. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47943.     

疏水花生壳/聚氨酯复合泡沫的制备与油水分离性能

为提高聚氨酯泡沫（PUF）的疏水性能,首先采用十六烷基三甲氧基硅烷（HDTMS）对花生壳粉末（PSP）进行改性,得到疏水改性花生壳粉末（H-PSP）。水接触角测试结果表明,改性后H-PSP的水接触角由PSP的0°提高至145.2°。然后采用预聚体法制备了PUF负载H-PSP复合材料（H-PSP-PUF-n,n为H-PSP占聚氨酯预聚体PPU的质量分数）。对H-PSP-PUF-n的结构和性能进行了表征与测试。结果表明,H-PSP的负载提高了泡沫材料的表面粗糙度和力学性能,H-PSP的最佳负载量为PPU质量的10%（H-PSP-PUF-10）。与PUF相比,H-PSP-PUF-10的静态水接触角达到142.4°,较PUF提高了50.4°。对二氯甲烷、石油醚、煤油、二甲苯、环己烷五种油品进行油水分离实验,结果表明,H-PSP-PUF-10对不同油品的吸油倍率在7~9 g/g,而且具有良好的油水选择性。经15次吸附-脱附循环后,H-PSP-PUF-10对各油品的吸油倍率在6.5~8.0 g/g,具有良好的循环利用性。     

疏水花生壳/聚氨酯复合泡沫的制备与油水分离性能

为提高聚氨酯泡沫（PUF）的疏水性能，首先，采用十六烷基三甲氧基硅烷（HDTMS）对花生壳粉末（PSP）进行改性，得到疏水改性花生壳粉末（H-PSP）。水接触角测试结果表明，改性后H-PSP的水接触角由PSP的0°提高至145.2°。然后，采用预聚体法制备了PUF负载H-PSP复合材料[H-PSP-PUF-n,n为H-PSP占聚氨酯预聚体（PPU）质量的百分数]。对H-PSP-PUF-n的结构和性能进行了表征与测试。结果表明，H-PSP的负载提高了泡沫材料的表面粗糙度和力学性能，H-PSP的最佳负载量为PPU质量的10%（标记为H-PSP-PUF-10）。与PUF相比，H-PSP-PUF-10的静态水接触角达到142.4°，较PUF提高了50.4°。对二氯甲烷、石油醚、煤油、二甲苯、环己烷进行油水分离实验，结果表明，H-PSP-PUF-10对石油醚、煤油、二甲苯、环己烷的吸油倍率在7～9 g/g，而且具有良好的油水选择性。经15次吸附-脱附循环后，H-PSP-PUF-10对各油品的吸油倍率在6.5～8.0 g/g，具有良好的循环利用性。     

Toward mechanistic understanding the effect of aspect ratio of carbon nanotubes upon different properties of polyurethane/carbon nanotube nanocomposite foam

This study investigated the carbon nanotube's aspect ratio's influence on the nanocomposite foams' cellular structure and mechanical, acoustic absorption characteristics. The free-rising foaming process has been used for producing different flexible polyurethane (PU) foams embedded with other multi-walled carbon nanotubes (MWCNT's). Dynamic mechanical and thermal analysis, flow resistivity, and compressive mechanical measurements were achieved on the prepared samples. The acoustic absorption coefficient in a wide range of frequencies was estimated for the prepared PU/CNT foamed nanocomposite samples. Results indicated that by increasing the aspect ratio of MWCNT, the absorption coefficient's peak shifts toward the lower frequencies and improved sound absorption characteristics of PU foam in the low-frequency region. Moreover, the Young modulus of nanocomposite samples increases by increasing the aspect ratio of MWCNT's, whereas the stored strain energy or area under the stress–strain curve increases. Based on the obtained results, it is observed that the acoustic absorption coefficient of produced nanocomposite foams at the frequency of 800 Hz has been reported to have a 70% improvement in 2 cm samples and a 40% improvement in 3 cm samples compared to obtained results from pure PU foam.     

Properties and mechanism of a novel metallic-hollow-spheres/polyurethane acoustic composite

In this article, 316L stainless steel hollow spheres (316L HS) and polyurethane (PU) resins were used to prepare a novel metallic-hollow-sphere/polyurethane (MHSP) acoustic composite by casting. The acoustic experimental results of this composite revealed that compared to monolithic PU, the sound transmission loss of the composites increased and the maximum sound absorption peak shifted to lower frequency with the change of acoustic impedance and resonance frequency. When the surface of metallic hollow sphere used in MHSP composite was modified by silane coupling agent, the sound insulation and sound absorption performance of MHSP composites were further improved. This is related to the addition of the molecular layer of coupling agent between MHSP matrix. In addition, the addition of silane coupling agent creates PU foaming in matrix, resulting in a large number of pores and gaps that can increase the sound waves energy loss through air friction and heat exchange.     

Numerical analysis on reaction injection molding of polyurethane foam by using a finite volume method

Foam reaction injection molding (FRIM) is one of the most popular and useful processes for producing polyurethane foam with a complex geometry. A theoretical model which includes chemical reactions, foaming, and mold filling was developed to analyze FRIM. Energy balance equation was derived by considering polyurethane reaction, water-isocyanate reaction, and evaporation of physical blowing agents. Density and viscosity model was proposed for the bubble suspension, which was assumed to be a homogeneous phase. Based on the theoretical model, three-dimensional numerical simulation for mold filling of the polyurethane foam was carried out to predict flow field, flow front advancement, and density distribution during mold filling. Mold filling of a refrigerator cavity was investigated numerically. The density and thermal conductivity of the foam in the flow front was higher than those in the initially filled region.     

The study of palm‐oil‐based bio‐polyol on the morphological,acoustic and mechanical properties of flexible polyurethane foams

The focus of this paper was to explore the acoustic properties of flexible polyurethane (FPU) foam modified by palm‐oil‐based polyol (POP). The presence of POP showed a marked influence on the microstructure and mechanical properties of FPU foam. A smaller mean pore diameter can be observed at lower POP content. Indeed, the introduction of POP caused a higher closed pore ratio and an increased air‐flow resistivity, which consequently improved the sound absorption coefficient and transmission loss. In particular, the acoustic performance of the all bio‐based FPU foam was enhanced at low frequency, and the density was lower than that of the reference foam. Additionally, the addition of POP also improved the compressive strength. Conversely, the tensile strength of FPU foam declined with increasing POP content. From this study, the outstanding acoustic ability of bio‐based FPU foam has been proved, with additional advantages of lower density and higher compressive strength. © 2019 Society of Chemical Industry     

新型CO2清洁泡沫压裂液性能研究

筛选了与CO2配伍的新型GRF清洁压裂液,采用大型泡沫循环回路,测试了GRF-CO2清洁泡沫压裂液的动态流变特性、携砂性能,同时评价了泡沫压裂液体系的静态破胶性能、助排性能和岩心伤害特性。结果表明,GRF-CO2清洁泡沫压裂液体系易破胶,破胶后无残渣,表/界面张力低,对岩心基质渗透率伤害低,当CO2泡沫质量达到55%~75%时,清洁泡沫压裂液体系流变性能好、动态携砂能力强,能够满足现场泡沫压裂施工的要求。     

Experimental study of horizontal flame spread over rigid polyurethane foam on a plateau: effects of sample width and ambient pressure

The effects of sample width and ambient pressure on horizontal flame spread over horizontal rigid polyurethane foams are experimentally studied. A series of comparative experiments are conducted at two places with different altitudes in China. The sample surface temperature, spread rate, and height of flame are measured over a range of sample widths from 4 to 16 cm. Experimental results show that the horizontal flame spread rate decreases as the sample width increases in a negative power law at both two altitudes and the flame spread rate in the Hefei plain (at an altitude of 30 m) is larger than that on the Tibetan plateau (at an altitude of 3658 m) of the same width. The horizontal flame spread mechanism on the rigid polyurethane foam is analyzed qualitatively in comparison with the results of the flame spread rate of expanded polystyrene foams. The relationship between the dimensionless flame height (H_f/W) and the sample width (W) is obtained by using Froude number similarity. It is found based on the experimental data under two different ambient pressures that the average value of the exponent of the ambient pressure in the power law for the horizontal flame spread rate is about 1.9, which is in good agreement with the theoretical value 2.0. Copyright © 2014 John Wiley & Sons, Ltd.     

藜麦蛋白泡沫分离工艺的优化及其功能特性分析

在单因素试验的基础上,采用 Box-Behnken 设计对藜麦蛋白的泡沫分离工艺条件进行优化,考察了料液比、装液量、温度和 pH值对藜麦蛋白回收率和富集度的影响,并对藜麦蛋白的亚基分布和功能特性进行了研究。结果表明：优化的工艺条件为: 温度35℃,pH值4.0,装料量260 mL,料液比0.3 mg·mL-1,在此条件下泡沫分离藜麦蛋白,藜麦蛋白的回收率为95.68% ,富集度为7.89;分离得到的藜麦蛋白具有分子量分别为50、32~39、22~23和8~9 kDa 的基本亚基,在60℃条件下,藜麦蛋白的最高持水量为9.733 g/g,最高持油量为5.848 g/g;随着原料与溶剂比例的增加,藜麦蛋白的乳化能力(EC)、乳化稳定性(ES)、起泡能力(FC)和泡沫稳定性(FS)均呈先增大后减小的趋势;其DPPH自由基清除率与剂量呈正相关,在藜麦蛋白浓度为2.5 mg/mL时,对3 mL 0.2 mmol·L-1的DPPH溶液中的DPPH自由基清除率达到(56.01±1.34)%。     

Glycerin as a new glycolysing agent for chemical recycling of cold cure polyurethane foam wastes in “split-phase” condition

Summary  In this communication, “Split-Phase” glycolysis of isocyanate derived cold cure foams, with glycerin as a new glycolysing agent, is reported. The process was simple and economically attractive among material recycling processes. Glycerin was used as a destroying solvent and sodium hydroxide as the catalyst, respectively. In order to study the ability of glycerin as a glycolysing agent and for selecting a system to obtain high quality recovered polyol, the effects of various reaction times were investigated and the characterization and comparison of upper and lower phases were performed by using instrumental (FT-IR, ¹HNMR and ¹³CNMR) and classical methods.     

响应面法优化松香基咪唑啉合成工艺及缓蚀性能研究

以3-氯-2-羟基丙烷磺酸钠为季铵化试剂,松香和二乙烯三胺为原料,聚乙二醇600为相转移催化剂,合成了松香基咪唑啉。在单因素试验的基础上,利用响应面法优化松香基咪唑啉的合成工艺条件为:反应时间5 h、催化剂用量为松香基咪唑啉中间体物质的量的14%、反应温度123℃、n(3-氯-2-羟基丙烷磺酸钠)∶n(松香基咪唑啉中间体)=0.89∶1、m(水)∶m(异丙醇)=2.14∶1,在此条件下松香基咪唑啉中间体进行S_N2亲核取代生成Na Cl的含量最高,为12.73%。采用红外光谱和核磁共振(~(13)C NMR)对较佳工艺条件下合成的松香基咪唑啉的结构进行了表征,同时测定了其在盐酸介质中的缓蚀性能,测试结果表明,以占盐酸质量0.6%的松香基咪唑啉作为缓蚀剂,在质量分数为15%的盐酸介质中30℃下腐蚀48 h,其对A3钢片的缓蚀率可达84.79%。     

一株卓贝尔氏菌的分离鉴定及氨氧化特性的优化

为了准确阐明卓贝尔氏菌对污染水体中NH4^+-N的氧化效率,以清河底泥为菌源,分离筛选出1株氨氧化能力较强的卓贝尔氏菌(Zobellella sp.)。考察了该菌株在不同培养条件下对NH4^+-N硝化效率的影响,利用响应面分析法对培养条件进行优化。结果表明,该菌株4 d内的氨氧化强度为27.88 mg/(L·d),当COD/ρ(TN)为11、pH为8.5、温度为25℃时,该菌在24 h内将NH4^+-N的质量浓度从171.1 mg/L降至11.88 mg/L,氧化效率高达93.06%;建立二次方程回归模型对实验数据拟合结果良好,优化后的培养条件为COD/ρ(TN)=10.72、pH=8.27、θ=25.72℃,在此条件下该菌的NH4^+-N氧化率为94.82%。可为污染水体中NH4^+-N去除的生物方法提供了理论指导依据。     

基于成本效益法优化新型滤筒除尘器结构

以内部具有锥体结构的新型滤筒除尘器为研究对象,基于成本效益法建立新型滤筒除尘器的经济性分析模型,对影响新型滤筒除尘器经济性的结构参数如滤筒褶数、锥体褶数、锥体高度、锥体上圆台半径及锥体褶高进行分析,基于Minitab软件代码平台利用响应面法分析结构参数对效益成本比的影响趋势和显著性,得到各影响因子的二次多项式预测模型,并优化其结构参数. 结果表明,结构参数对效益成本比影响的显著性水平为锥体褶数(N1)>滤筒褶数(N2)>褶高(h2)>锥体高(h1),而锥体上圆台半径r的影响不显著. 在给定的参数范围内,当N1=264, h1=0.8 m, N2=350, h2=0.05 m时,取得的最大效益成本比为33.25%.     

基于响应面法的综合抗渗自愈性能水泥基渗透结晶防水材料制备方案优化

因水泥基渗透结晶防水材料施工工艺简单、工作效率高、综合成本低,已成为防水工程领域研究的热点.以络合剂ES、无机硅助剂HS、无机防水剂GS和无机防水剂TS为原料制备活性复合剂,基于响应面法研究了水泥基渗透结晶防水材料中上述成分对其综合抗渗自愈性能的影响,结果表明,水泥基渗透结晶防水材料中各组分对综合抗渗自愈性能的显著性顺...     

基于正交试验的高铁橡胶外风挡注射成型工艺参数优化

基于Moldflow软件,采用正交试验和响应曲面法,对高铁橡胶外风挡注射成型的模拟方案优化设计,并对注射成型工艺参数进行研究。结果表明:模具温度是影响橡胶外风挡顶出时的体积收缩率和缩痕指数的最显著工艺因素,其次分别是熔体(胶料)温度、保压时间、保压压力、注射时间;优化的注射工艺参数为:模具温度185℃,熔体温度65℃,注射时间160 s,保压时间14 s,保压压力110 MPa。在此工艺参数下的橡胶外风挡顶出时的体积收缩率最大值为4.165%,缩痕指数最大值为5.103%。