活性碳纤维材料吸声理论模型建立

参照圆管理论模型,以活性碳纤维毡内部微小通道为基础,确定活性碳纤维材料微孔中空气有效密度和有效压缩模量,建立活性碳纤维材料的吸声理论模型。接着,利用双通道阻抗管声学分析仪,测试活性碳纤维毡在250～6 300 Hz声波频率范围内的吸声系数,对比并分析计算的理论值和实测值。结果发现:理论值与实测值基本一致,这表明建立的活性碳纤维材料的吸声理论模型具有可行性。该模型可为设计和开发活性碳纤维吸声材料提供理论与技术支持。     

活性碳纤维的性能及发展现状

介绍了活性碳纤维的吸附机理,阐述了活性碳纤维的性能特点,并对活性碳纤维发展现状进行了综述。     

梯度结构活性碳纤维毡吸声性能分析

为研究梯度结构活性碳纤维毡的吸声性能,选取5种不同密度的粘胶基活性碳纤维毡,两两组合构成梯度结构,借助阻抗管在250~6 300 Hz频率声波范围内,对梯度结构活性碳纤维毡法向入射吸声系数进行测试,分析梯度方向、密度、结构对吸声性能的影响。结果表明:总密度相同的情况下,在低频段单一结构活性碳纤维毡吸声性能比正梯度结构好,但比倒梯度结构差,而在高频段单一结构吸声性能比正梯度结构差,但比倒梯度结构好;总密度不同的情况下,在低频段随着梯度结构总密度的增加,其吸声系数增加,而在高频段随着梯度结构第1层密度的增加,其吸声系数减小;随着活性碳纤维毡第1层密度的增加,第一共振频率向低频移动,随着总密度的增加,第一共振吸声系数增加。     

活性碳纤维理化性能测试的几种方法

归纳了活性碳纤维理化性能测试的几种方法,包括活性碳纤维预氧化程度的测试方法、活性碳纤维碘吸附值测试法、四氯化碳蒸气吸附率测试法和采用BET容量法的比表面积测试法等,有利于工厂和科研参考与应用.     

碳纤维的性能与应用

系统的介绍了碳纤维的性能及其广泛的用途，重点说明了碳纤维的高强度及其复合材料（CFRP），并涉及到碳纤维应用的新领域，如针刺碳纤维毡用刹车制动片，碳纤维面状发热板的远红外保健功能。     

吸声衬垫材料物理化学性能的改善

<正> 本文作者对用再生毛和粘胶纤维的下脚料(Ty-ЭCCP 409-77)加工的汽车车厢用衬垫材料以及以聚氯乙烯纤维和聚酯丝下脚料为主的衬垫材料的吸声特性进行了研究。已确定在声频为1500Hz～5500Hz时,用聚氯乙烯纤维和聚酯丝下脚料制造的非织造布与用聚酰胺丝下脚料制造的针刺衬垫布具有相同的吸声系数。由此可得出结论:吸声系数几乎不取决于合成纤维下脚料的性质,而仅取决于其在混合中所占的数量。 同时指出,再生毛和粘胶纤维的抗微生物作用不强,易腐败和燃烧。为了排除这些缺点,研究了用聚乙烯醇以及聚乙烯醇下脚料制得的再生毛和粘胶纤维下脚料生产的针刺非织造布的吸声性能。聚乙烯醇是白色的粉状物质,用聚乙烯醇加工     

汽车内饰材料的吸声性能

分析了针刺非织造汽车内饰黄麻毡的面密度与吸声性能的关系,并在黄麻纤维中混入一定量的铝纤维,分析铝纤维的混入质量、混合方式对其吸声性能的影响.结果表明:在同一测试声波频率下,黄麻毯的吸声性能随着面密度的增加而提高,在面密度为764 g/m2时吸声性能最好;铝纤维的加入有利于吸声性能的提高,吸声性能随着铝纤维含量的增加而提...     

双层复合非织造材料基吸声体吸声性能研究

以熔喷丙纶非织造材料和玻璃纤维水刺非织造材料为受声面和背衬层,通过热粘合方式制成双层复合非织造材料基吸声体。通过分析吸声体受声面和背衬层非织造材料的厚度、面密度、孔径、孔隙率等结构参数与复合吸声体的吸声系数之间的关系,探讨各层非织造材料结构参数对复合吸声体吸声性能的影响。实验结果表明,随着熔喷丙纶非织造材料和玻璃纤维水刺非织造材料厚度和面密度的增加,吸声体中高频段吸声系数显著提高;受声面和背衬层的孔径尺寸和孔隙率的变化对双层复合非织造材料基吸声体的吸声性能影响较为显著。     

活性碳纤维的研究开发与应用

在简介活性碳纤维制备的基础上，对活性碳纤维的液，气相吸附特性进行了说明，概述了活性碳纤维的主要应用，并介绍了国内研究开发简况。     

废弃纤维吸声复合材料的制备及其吸声性能

针对废弃纺织纤维利用率不高的问题,采用共混-热压工艺,以废弃纤维为增强材料,以热塑性聚氨酯为基体材料,制备废弃纤维/聚氨酯复合材料。将废弃纤维/聚氨酯复合材料加工成穿孔板,并与废弃涤纶织物贴合,构成吸声复合材料。重点研究吸声复合材料中穿孔直径、穿孔板厚度、穿孔率及废弃涤纶织物层数四种结构参数对材料吸声性能的影响。结果表明,穿孔直径主要影响吸声材料的吸声系数峰值;穿孔板厚度、穿孔率和废弃涤纶织物的层数主要影响吸声材料的吸声频带范围。     

The influence of production parameters on sound absorption of activated carbon fiber felts

Intended to study the influence of different production parameters on sound absorption of activated carbon fiber felts, viscose-based activated carbon fiber felts acquired from different production parameters were prepared and taken to test the sound absorption coefficients in normal incidence by means of transfer function method, within an acoustic range of 250–6300 Hz in the impedance tube. Analysis was made to find the influence of carbonization temperature, carbonization rate, activation temperature, and activation time on sound absorption properties. Sound absorption coefficients at medium–low frequencies strikingly climbed with the increasing frequency, while fluctuating at high frequencies. Other production parameters remaining constant, sound absorption coefficients increased at medium–low frequencies with the rising carbonization temperature and the extended activation time, while subsequently decreased with the rising carbonization rate and carbonization temperature. At the same time, sound absorption coefficients decreased at high frequencies with the rising carbonization temperature and carbonization rate, while increased but later decreased with the rising activation temperature, and increased again with the added time in activation.     

Sound absorption properties of composite structure with activated carbon fiber felts

This paper is intended to study the influence of different factors on the sound absorption properties of composite structure with activated carbon fiber felts. Activated carbon fiber felts made from viscose fiber mats were prepared and later combined with perforated panels to form four different composite sound absorption structures. Based on the transfer function method, the impedance tube was used to test the sound absorption coefficients of composite structure in an acoustic range of 80–6300?Hz frequencies. Analysis was made to discuss the influence of such factors on the sound absorption properties as the position of activated carbon fiber felts, thickness, and air space. The results demonstrated that the composite structure displayed different sound absorption properties at different frequencies. Perforated panels played the dominant role in sound absorption by the occurrence of resonance at 80–3500?Hz frequencies, while porous materials contributed the most at 3500–6300?Hz frequencies. At 80–3500?Hz frequencies, the best performance could be observed in the third type of composite structure with changes in the position of activated carbon fiber; the first resonance frequency of the first type of composite structure and perforated panel structure was basically the same, and that of the remaining three types significantly shifted towards the low frequencies with the same scale. In smaller thickness range, with the increase in the thickness of activated carbon fiber felts, sound absorption coefficients of the first and second types of composite structure increased, the first resonance frequency of the first type showing no apparent shift towards the low frequencies compared with what was shown in the second type; but when the thickness arrived at 15.6?mm, sound absorption properties of the composite structure had similar traits to that performed by porous materials in an acoustic range of 80–6300?Hz frequencies. With the increase in the distance of air space, sound absorption properties were improving at 80–650?Hz frequencies but decreasing at 650–3500?Hz frequencies, the first resonance frequency moving towards the low frequencies. At 3500–6300?Hz frequencies, as the position of activated carbon fiber felts and the distance of air space varied, sound absorption coefficients were basically unchanged; while as thickness increased, sound absorption coefficients improved.     

活性炭纤维材料吸声性能预测模型

为了建立活性炭纤维材料吸声性能预测模型,利用阻抗管对不同规格的粘胶基活性炭纤维材料在250-1600Hz中低频率声波范围内的吸声性能进行测试,根据Delany和Bazley提出的特性阻抗率和传播常数理论模型,采用最小二乘法建立了活性炭纤维材料声学特征参数特性阻抗率和传播常数预测模型。在此基础上,建立了活性炭纤维材料吸声系数模型,并对该模型计算结果和试验结果进行了比较,结果表明两者结果基本相一致,验证了建立的活性炭纤维材料吸声性能预测模型具有一定的可信度,为开发和设计活性炭纤维吸声材料提供理论依据。     

活性炭纤维材料吸声性能分析

为研究活性炭纤维的吸声性能,在同一工艺条件下制备了不同规格粘胶基活性炭纤维毡,用传递函数法在250～1 600 Hz中低频率声波范围内采用阻抗管对活性炭纤维材料的吸声性能进行测试,分析材料比表面积、厚度、面密度、空腔厚度等参数对吸声性能的影响。结果表明:活性炭纤维毡多孔材料具有较好的吸声性能,其对声波中频段的吸声好于低频段,随材料的比表面积、厚度、面密度、空腔厚度的增加,其吸声性能越好,但平均吸声系数增幅不同。     

活性炭纤维形态对吸附性能的影响

比表面积和孔结构是影响活性炭纤维吸附性能的重要因素。选用相同的活化工艺,制备相似孔结构和比表面积的活性炭毡和活性炭布,讨论在比表面积相近的情况下,活性炭纤维的形态和厚度对吸附性能的影响。结果表明:在一定条件下,活性炭毡的吸附性能略优于活性炭布,活性炭纤维的吸附能力并不随着活性炭织物厚度的增加而线性增强。     

Effects of different parameters on acoustic properties of activated carbon fiber felts

The aim of this study is to explore the effects of different parameters on acoustic properties of activated carbon fiber felts. Seven viscose-based activated carbon fiber felts with different specifications were selected to test the sound absorption coefficients in normal incidence by using transfer-function method and an impedance tube in an acoustic range of 250–6300?Hz frequencies, and to analyze the effects on acoustic properties caused by factors such as: thickness, bulk density, and fiber diameter. The result demonstrated that activated carbon fiber felts exhibited exceptional acoustic properties. As frequency increases, sound absorption coefficients of less-thick felts went upwards in the whole range of frequencies; when the thickness amounted to 9?mm, sound absorption coefficients showed a sharp increase at low frequencies and a fluctuation at high frequencies. With the increase in thickness and bulk density, sound absorption properties improved first and then impaired at the same level of frequency; with a decrease in the fiber diameter, properties enhanced at the same level of frequency. When thickness and bulk density increased and fiber diameter decreased, sound absorption coefficients of the first resonance frequency displayed an upward trend to different degrees, while the first resonance frequencies declined discrepantly.     

废弃玉米秸秆的结构特征及其吸声性能

为增加废弃玉米秸秆的回收利用率,分别以长度为1.5、6和10 mm的废弃秸秆颗粒、棉纤维和大麻纤维为增强材料,聚己内酯为基体材料,通过热压成型工艺制备厚度为1.5 cm的吸声复合材料。采用声阻抗传递函数法对复合材料的吸声性能进行测试与对比,并分析其吸声机制。结果表明:1.5 mm长的废弃秸秆所制备复合材料的吸声性能最好,最大吸声系数达到0.71,平均吸声系数为0.50,降噪系数达到了0.51;废弃秸秆纤维素大分子主链上的氧六环结构为声波反复反射、折射提供了基础,较高的线性使得氢键等单键能够自由旋转,增加了声波能量的消耗,且废弃玉米秸秆的结晶度低使得声能易于沿着分子链传播,从而将声能转化为分子链段振动耗散。     

活性炭纤维材料声学特性参数研究

为了分析活性炭纤维材料两个最基本的声学特性参数传播常数和特性阻抗,根据声波在活性炭纤维材料中传播的基本理论,通过运动方程和连续性方程,建立了传播常数和特性阻抗理论模型;利用阻抗管测试活性炭纤维材料在频率声波范围内表面阻抗,采用两倍厚度法确定活性炭纤维材料传播常数和特性阻抗,并对两个声学特性参数的理论和试验结果进行对比分析,结果表明声学特性参数理论模型具有可行性,为开发和设计活性炭纤维吸声材料提供理论依据。