水下吸声橡胶的性能研究

利用自制的小型声脉冲管装置研究水下吸声橡胶的声学性能。并考察几种常用配合剂及蛭石粉、玻璃微珠对橡胶吸声性能的影响。     

深水下的吸声材料

由于丁基橡胶的基本结构具有多足虫状，它的粘弹性损耗因子比其他几种通用橡胶都高。因此，水下吸声材料多采用丁基橡胶。当吸声橡胶在水下处在0．5MPa的压力下，即变成了透声橡胶。国外有人用SOAB吸声橡胶做过声管试验，在0．7MPa下声波几乎完全透过，故SOAB在高静水压下则失去吸声作用。SOAB吸声产品是丁基橡胶加入铝粉制成。我国的吸声橡胶产品是由丁基橡胶加蛭石粉制成的，同样也只适用于常压下工作。     

纤维/聚氨酯泡沫复合材料的制备及吸声性能研究

通过热压发泡法制备了一系列竹粉、木粉、改性木粉纤维/聚氨酯泡沫复合材料,研究了不同填料及填料含量对聚氨酯发泡复合材料吸声性能的影响。添加纤维的聚氨酯泡沫复合材料吸声峰向低频移动,吸声性能有所提高。     

聚氨酯杂化复合泡沫体声学材料的研究

采用空心玻球、蛭石粉、粉末橡胶、有机蒙脱土和铅粉作为功能粒子,与聚氨酯杂化复合发泡,制得了聚氨酯杂化复合泡沫体声学材料。研究结果表明,加入20份上述不同功能粒子所制得的复合泡沫,它们之间的吸隔声性能差别不大,当厚度为25 mm时,在125~4000 Hz范围内的平均吸声系数在0.12~0.19之间,平均隔声量在12.0~13.9 dB之间,但它们的泡孔结构有较大的差别,其中,铅粉/PU复合体系的泡孔尺寸最粗,而有机蒙脱土/PU纳米复合体系的泡孔结构分布较均匀。所制得的几种复合泡沫都具有较高的拉伸强度,达到0.126 MPa以上,粉末橡胶/PU复合体系的泡沫拉伸强度达到0.406 MPa。     

橡胶吸声材料及其应用

简介橡胶吸声材料的吸声原理、吸声性能影响因素和应用领域.橡胶所具有的较大的损耗因子和适宜的特性阻抗确保其可用作吸声材料;影响橡胶吸声材料吸声性能的因素主要有橡胶分子微观结构、填料和橡胶制品结构;橡胶吸声材料主要可用于轮胎降噪,水下消声和消声瓦等方面.     

聚丙烯/硅藻土复合材料性能研究

采用铝酸酯偶联剂对硅藻土进行表面改性,以不同含量的硅藻土与聚丙烯(PP)熔融共混,并加入一定量NaCl,制备PP/硅藻土复合材料,研究铝酸酯偶联剂对硅藻土的改性效果,分析不同硅藻土含量对PP/硅藻土复合材料的组织形貌及吸声系数和压缩性能的影响。结果表明,铝酸酯偶联剂对硅藻土改性效果明显,随着硅藻土含量的增加,复合材料的吸声性能和压缩强度逐渐增大,并在硅藻土含量为30份时吸声系数最佳,最大达0.68;硅藻土含量为40份时压缩强度达到12.66MPa;随着NaCl含量的增加吸声系数有一定改善,当NaCl含量为PP的20%时吸声系数最大达0.78。     

钢渣粉改性SEBS/蛭石复合材料的隔声性能研究

将蛭石填充到钢渣粉改性过的苯乙烯-乙烯-丁二烯-苯乙烯(SEBS)/钢渣粉基体中,用模压法制备不同配比、不同目数和不同面密度的SEBS/钢渣粉/蛭石复合材料。利用双通道声学分析仪,研究了其隔声性能;利用扫描电子显微镜(SEM)、万能材料试验机等研究了材料的微观结构、拉伸力学性能等。结果表明,经钢渣粉改性的SEBS与蛭石相容性较好,制作出的复合材料隔声性能优于基体材料;在相近面密度条件下,蛭石含量的变化对隔声性能的影响主要在声频1 600 Hz的区域;蛭石目数的变化对复合材料隔声性能影响不大;复合材料的隔声量随着材料面密度的增大而增大,主要体现在声频段200~1 600 Hz。     

化学改性蛭石粉填充溴化丁基橡胶性能研究

研究化学改性蛭石粉填充溴化丁基橡胶(BIIR)的性能。结果表明:与填充未改性蛭石粉的BIIR胶料相比,填充改性蛭石粉的BIIR胶料的硫化速度明显提高,最大转矩增大,硫化胶的硬度、拉断伸长率和撕裂强度均有所提高,拉伸强度显著提高,损耗因子减小,玻璃化温度升高;填充改性蛭石粉的BIIR硫化胶的断面有较多脊痕线,且分布没有规律,断面规整性差。化学改性能够改善蛭石粉的分散性,改性蛭石粉作为填料可以提高BIIR硫化胶的性能。     

橡胶薄片共振结构吸声机理及性能研究

本文用驻波管法研究了橡胶薄片共振吸声结构的吸声机理及橡胶薄片厚度、空气层厚度和声波频率对其吸声性能的影响。实验结果表明,橡胶薄片共振结构与普通板共振结构在吸声机理和吸声效果方面均有所不同,前者的吸声效果优于后者;在共振状态,前者的吸声作用主要在于柔性橡胶薄片在声波作用下弹性振动,引起后面腔体内空气压强的变化,因空气层的吸声作用而损耗声能,后者主要依赖于板的内摩擦吸声作用。橡胶薄片共振的吸声系数随空气层厚度的变化而出现一极大值,随着声波频率的增加,达到共振状态所需的空气层厚度减小,随着橡胶薄片厚度的增大,其最大吸收峰向低频方向移动。     

聚丙烯基吸声建筑材料的制备

采用铝酸酯偶联剂对硅藻土表面改性,以不同含量的硅藻土与聚丙烯熔融共混,制备具有一定力学性能和吸声性能的吸声建筑材料。采用红外光谱仪、扫描电子显微镜、电子拉力试验机和传递函数阻抗管吸声测试系统对硅藻土改性效果和试样的微观组织、力学性能和吸声性能进行测试分析。研究表明,铝酸酯偶联剂对硅藻土改性效果明显,改性后硅藻土表面形成一层有机包覆层,增强了硅藻土与聚丙烯界面的黏结效果;试样的吸声性能随着硅藻土含量的增加呈现先增后减的趋势,当硅藻土含量30份时吸声性能最佳,在2 000 Hz左右试样的吸声系数达到最佳值约为0. 78,高效吸声频率宽度超过2 200 Hz,试样的压缩强度和弹性模量为12. 75 MPa和0. 38 GPa,可将该材料用于声学工程设计和噪音控制等方面,以达到控制混响时间和吸声降噪的目的。     

环氧树脂/蛭石纳米复合材料的制备与表征

以环氧树脂为基体,二甲基苄胺为固化剂,经酸浸、加热和钠离子交换的结构修饰和有机改性的蛭石为增强剂,制备了环氧树脂/蛭石纳米复合材料.测试了环氧树脂/蛭石纳米复合材料的结构、形貌、力学和电学性能.结果表明:环氧树脂、二甲基苄胺和蛭石的混合顺序,二甲基苄胺和蛭石的用量影响蛭石的剥离,进而影响环氧树脂/蛭石纳米复合材料的性能.在蛭石加入量为环氧树脂质量的1%～5%范围内,3%时环氧树脂/蛭石纳米复合材料的抗拉强度、弹性模量和弯曲强度最大,表面电阻最低,体电阻最高.     

聚氨酯涂层的合成及其吸声性能研究

以聚氨酯为涂层基体,研究了石墨作为填料对涂层吸声性能的影响。试验结果表明,石墨改变了涂层的密度,提高了涂层的吸声系数。合成的高性能聚氨酯涂层随着水压的增大,涂层的吸声系数增加,水压在3 MPa时,平均吸声系数达87.6%。     

Open-cell porous sound-absorbing ceramics prepared by a new procedure that combines foamed and templated methods

Low-grade nonmetal ore, mainly magmatic soil and tuff, was used to prepare porous sound-absorbing ceramics. A new processing method that combines the foaming and templating methods was used to produce open-cell porous ceramics. Silicon carbide and carbon powders were used as the foaming agent and template agent, respectively, and their effects on open-cell preparation and sound-absorption properties were also investigated. The results showed that sound-absorption performance was closely related to the apparent porosity (H). Compared with either foaming or template methods, the new method incorporating both processes increased the sound-absorption coefficient (α) and H by 51%-258% and 69%-728%, respectively. Optimum sound absorption of the ceramics, that is, α = 0.68, noise reduction coefficient (NRC) = 0.48, and H = 50.22%, were obtained at foaming agent contents (FACs) of 1.5 wt% and template agent contents (TACs) of 4 wt%. The Delany-Bazley and Voronina models were selected to simulate the sound-absorption coefficients and the latter one fitted well with our experimental results.     

Water-retention properties of porous ceramics prepared from mixtures of allophane and vermiculite for materials to counteract heat island effects

Porous ceramics for anti-heat island effect were prepared from mixtures of allophane and vermiculite (VA samples). Allophane and vermiculite which had been ground for 0.5–2 h was mixed in various mass ratios, formed into pellets by uniaxial pressing at 40 MPa, and heated at 600–800 °C to form porous ceramics. The large thermal expansion of the vermiculite upon explosive dehydration of interlayer water causes cracking of the pellets with higher vermiculite contents. However, this can be controlled by grinding the vermiculite prior to heating. Grinding the vermiculite for ≥2 h suppresses its expansion, enabling pellet samples with high vermiculite contents to be prepared without cracking. The bulk densities of samples prepared at 800 °C from vermiculite ground for 2 h decrease from 1.72 to 0.94 with increasing allophane content. The pore size distribution in these samples shows a distinct peak at about 1 μm irrespective of the mixing ratio. The number of smaller pores (<50 nm) increases with increasing allophane content while the number of larger pores (20–40 μm) increases with increasing vermiculite content. The compressive strengths of the samples range from 1 to 3 MPa except for samples containing a high proportion of vermiculite ground for 1 h. The water absorption (W_a) of the samples increases from 37 to 63% with increasing allophane content. This absorption rate is fast enough to absorb >90% of the W_a within 1 min for samples of 10 mm Ø × 5 mm³ size. By contrast, the release of the absorbed water is very slow, with 50% of the W_a retained for ≥30 h in the VA samples at a relative humidity of 55% at 20 °C; this is slower than in pure allophane and much slower than in a reference sample of foamed glass (about 4 h). All these properties make the VA samples useful as water-retaining materials to combat “heat island” effects.     

尼龙610/蛭石纳米复合材料的阻隔阻燃性能

在对蛭石钠化和有机化修饰后,通过熔融共混法制备了尼龙610/蛭石纳米复合材料,研究了复合材料的阻隔阻燃性能。研究结果表明,随蛭石含量的增加,尼龙610/蛭石复合材料的透水汽速率和吸水率显著下降,当蛭石质量分数为5%时,复合材料的透水汽速率的能力仅为尼龙610原样的39.4%,吸水率为尼龙610原样的55%,蛭石的加入显著改善了尼龙610的阻隔性能。复合材料的极限氧指数(LOI)和质量保持率随蛭石含量的增加明显增大,热变形温度升高,复合材料燃烧时熔滴现象消失。蛭石与三聚氰胺氰脲酸盐的协同作用,使尼龙610的LOI达到30%左右,为难燃材料,尼龙610的阻燃能力增强。     

马来酸酐改性蛭石的制备及表征

以有机小分子马来酸酐作为改性剂,利用球磨法在不同溶剂中对蛭石进行有机改性.对有机改性的蛭石进行了X射线粉晶衍射、Fourier变换红外光谱仪和热重分析表征.结果表明:在水溶液条件下,球磨能够使蛭石片层被马来酸酐分子剥离,蛭石的(001)面特征衍射峰消失.在有机溶剂中球磨,蛭石不能够被马来酸酐剥离.讨论了马来酸酐改性蛭石的机理.研究了球磨时间对马来酸酐改性蛭石的影响.     

Comparative evaluation of acoustical properties of heat-bonded and needle-punched fibrous materials prepared from polymer melts

Conclusions The acoustical properties of heat-bonded and needle-punched fibrous materials have been studied by the steady-state method.The basic structural and technological parameters which affect the sound-absorption coefficient of these materials have been established.It has been shown that heat-bonded fibrous materials have advantages over the needle-punched ones, since they ensure an equal sound-absorption coefficient at a lower thickness.Translated from Khimicheskie Volokna, No. 6, pp. 27–28, November–December, 1989.     

蛭石基流延浆料的流变性能研究

以改性膨胀蛭石和滑石填料为原料,蓖麻油为分散剂,聚乙烯醇缩丁醛(PVB)为粘结剂,邻苯二甲酸二丁酯(DBP)为增塑剂,采用球磨法制备蛭石基流延浆料。考察浆料固含量和各组分添加量对浆料流变性能的影响,得出了合适的浆料配方为:固含量质量分数为50%、蓖麻油用量为粉体质量的2%、PVB用量为粉体质量的6%、DBP用量为R=0.8时,流延浆料具有典型剪切变稀行为的塑性流体特性,该配方制备的蛭石基流延坯料表面均匀,无裂纹。     

Mechanical properties of gamma‐irradiated styrene‐butadiene rubber/acid‐treated vermiculite clay/maleic anhydride nanocomposites

Nanoparticle vermiculite (VMT) clay was prepared by treatment with hydrochloric acid. Styrene‐butadiene rubber (SBR) nanocomposites were prepared by mixing different contents (2.5, 5, 7.5, and 10 phr) of untreated (VMT) and acid‐treated (DVMT) vermiculite clay, respectively. In addition, different contents (3, 7, and 10 phr) of maleic anhydride (MA) as compatibilizer were mixed via direct melt compounding in internal mixer. The effect of gamma irradiation, VMT clay, and MA contents on the mechanical properties was studied. The acid‐treated VMT clay was characterized by x‐ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared (FT‐IR) spectroscopy. Meanwhile, the SBR/VMT composites, SBR/DVMT, and SBR/DVMT/MA nanocomposites were characterized via crosslinking density and tensile mechanical testing and FT‐IR spectroscopic analysis. The results indicated that good yield of nanoparticle vermiculite was achieved when the acid treatment was carried out for 120 h. In addition, the results showed that the presence of DVMT clay improved the chemical bonding in the SBR nanocomposites and hence their mechanical properties. The highest improvement was obtained when the contents of DVMT clay, MA, and irradiation dose were 10 phr, 3 phr, and 100 kGy, respectively. POLYM. ENG. SCI., 59:355–364, 2019. © 2018 Society of Plastics Engineers     

三聚氰胺泡沫的制备及应用研究进展

介绍了三聚氰胺泡沫制备技术开发进展及国内外产品生产现况,综述了三聚氰胺的非声学参数测定,泡沫吸音性能、吸附性能、阻燃、隔热性能及其应用,并对国外将三聚氰胺泡沫用于航空航天、汽车和轨道车辆等领域的研究作了报道。