白炭黑与硅藻土填充丁基橡胶的性能对比研究

研究白炭黑和硅藻土对丁基橡胶(IIR)加工性能、物理性能和动态力学性能的影响。结果表明:与硅藻土相比,随着加工时间的延长,白炭黑填充IIR胶料的加工性能较优,硫化胶的邵尔A型硬度和拉伸强度较高,拉断伸长率较低;在低温阶段,白炭黑填充IIR硫化胶的储能模量(E′)较大,而在高温阶段,两种填料填充IIR硫化胶的E′相当;当频率为0.1~200 Hz时,白炭黑填充IIR硫化胶的损耗因子较大,E′在低频(150 Hz)时较小,而在高频(≥150 Hz)时则较大。     

烷偶联剂原位改性白炭黑/溶聚丁苯橡胶 复合材料的流变性能和力学性能研究

制备3种硅烷偶联剂（Si69,Si75,NXT）原位改性白炭黑/溶聚丁苯橡胶（SSBR）复合材料,研究硅烷偶联剂对白炭黑/SSBR复合材料流变性能和力学性能的影响。结果表明：硅烷偶联剂NXT在降低善白炭黑填料网络化程度方面比偶联剂Si69和Si75的效果更明显;硅烷偶联剂NXT改性白炭黑/SSBR复合材料（混炼胶和硫化胶）的剪切储能模量较低,Payne效应较弱,加工性能较好,损耗因子和活化能较小,拉伸储能模量对温度依赖性较弱,硬度、拉伸强度和拉断伸长率相当,撕裂强度较大,白炭黑分散性优异,白炭黑与橡胶之间的相互作用较强。     

炭黑N660用量对溴化丁基橡胶动态力学性能的影响

用橡胶加工分析仪(RPA)等研究了炭黑N 660填充量不同的溴化丁基橡胶(BIIR)的性能。结果表明,BIIR混炼胶的门尼黏度随炭黑填充量的增加而线性增大。炭黑填充量为40份(质量,下同)时填料网络明显。经过3次应变扫描发现,炭黑填充量为30份时BIIR混炼胶开始出现填料网络,且在RPA应变扫描时应变大于10%后填料网络几乎被完全破坏;损耗因子随炭黑填充量的增加而增大,应变依赖性增强。随RPA应变扫描温度的升高,BIIR混炼胶的储能模量下降,对应变的依赖性减弱,损耗因子增大。填充40份炭黑的BIIR硫化胶具有较高的拉伸强度和扯断伸长率。     

橡胶操作油用量对溶聚丁苯橡胶性能的影响

研究在溶聚丁苯橡胶（SSBR）和白炭黑配方体系中,橡胶操作油（简称操作油）用量对胶料性能的影响。结果表明：随着操作油用量的增大,胶料的门尼粘度、F_L和F_max减小,t₅和t₉₀延长;硫化胶的邵尔A型硬度、定伸应力和拉伸强度减小,拉断伸长率、撕裂强度和回弹值增大,耐磨性能和抗切割性能下降,弹性模量和粘性模量减小,0和70 ℃时的损耗因子变化不大,玻璃化温度（T_g）降低。SSBR胶料的门尼粘度、焦烧时间和转矩以及硫化胶的邵尔A型硬度、定伸应力、拉断伸长率、回弹值和T_g均与操作油用量之间具有高度线性相关性。     

填料种类对丁基橡胶/聚丙烯热塑性硫化胶性能的影响

从微观形貌、Payne效应、力学性能和动态力学性能等方面研究了分别以轻钙、钛白粉、白炭黑和滑石粉作为填料时对丁基橡胶/聚丙烯热塑性硫化胶(TPV)性能的影响。结果表明,轻钙、钛白粉和白炭黑填料的微观形貌接近球状,粒径依次减小。未加填料的TPV呈现出两相结构,填料可以减小TPV中橡胶相的尺寸;轻钙和钛白粉填料在TPV两相中分散得较为均匀,白炭黑有少量团聚现象,滑石粉则呈片状结构无规则地穿插在TPV的两相中。填料可以提高TPV的储能模量和Payne效应,其中添加钛白粉TPV的网络结构最强;填料也可以提高TPV的拉伸强度,其中添加钛白粉TPV的拉伸强度和扯断伸长率最大,添加滑石粉与添加轻钙TPV的拉伸强度接近。添加不同填料所制备TPV中聚丙烯相的玻璃化转变温度相差不大,丁基橡胶相则有明显差别,填料可以提高丁基橡胶相的玻璃化转变温度,其中以添加钛白粉的TPV为最高。     

不同用量白炭黑对NBR/BRR的动态力学性能和Payne effect效应的影响

本文利用扫描电镜SEM和橡胶加工分析仪(RPA-2000)设备,研究了不同白炭黑用量的NBR/BR并用胶的动态性能和微观形貌。结果表明：随着白炭黑用量的增大,白炭黑聚集体增多,白炭黑与橡胶基体间的相互作用增大,混炼胶的Payne效应增大。动态性能方面,随温度升高,NBR/BR混炼胶损耗因子先增大后减小;随白炭黑用量增大,NBR/BR混炼胶损耗因子在低温时增大,高温时减小;随温度升高, NBR/BR硫化胶储能模量G’变化不大,损耗因子减小。随白炭黑用量增大,NBR/BR硫化胶储能模量G’增大,损耗因子增大;随着温度的升高,NBR/BR硫化胶的损耗因子先增大后减小。     

不同填料填充丁腈橡胶力学性能与阻尼性能的研究

研究了不同填料填充丁腈橡胶的力学性能和阻尼性能。结果表明:填料种类与用量对丁腈橡胶的力学性能与阻尼性能有显著影响。随着填料用量增加到30份,拉伸强度和硬度呈现增大的趋势,断裂伸长率却随之降低。当填料用量超过30份,拉伸强度和断裂伸长率下降,硬度先增大后减小。在不同频率下,不同填料填充NBR的阻尼损耗因子各不相同,所表现出来的阻尼性能有所差异。     

白炭黑/溶聚丁苯橡胶复合材料的填料网络结构与动态黏弹性能

用橡胶加工分析仪研究了白炭黑用量和偶联剂Si 69原位改性对白炭黑/溶聚丁苯橡胶复合材料中填料网络结构与动态黏弹性能的影响.结果表明,白炭黑用量为30份(质量,下同)时网络结构尚未形成,不能测定结合胶;填充了50份和 70份的白炭黑复合材料的结合胶含量较低,其网络结构的结点类型以刚性结点为主,混炼胶和硫化胶的Payne效应明显.混炼胶的温度扫描结果表明,随白炭黑用量增加,复合材料中填料的聚集程度加剧.经Si 69原位改性后,复合材料的结合胶含量大大提高,网络结构的结点类型以柔性结点为主,混炼胶和硫化胶的Payne效应明显减弱.在10.04%的大应变下进行频率扫描时,经Si 69原位改性硫化胶的储能模量和损耗因子随频率的增大而增大,且明显低于未改性者.     

气相法白炭黑对硅橡胶混炼胶性能的影响

以甲基乙烯基硅橡胶为基胶,气相法白炭黑为填料,制得硅橡胶混炼胶。研究了气相法白炭黑的比表面积、灼烧减量、吸油值对硅橡胶混炼胶性能的影响。结果表明,随着白炭黑比表面积的增加,硅橡胶混炼胶的拉伸强度增加,拉断伸长率降低;当白炭黑比表面积大于240 m~2/g时,硅橡胶混炼胶易出现结构化;随着白炭黑灼烧减量的增加,硅橡胶混炼胶的拉伸强度增加,拉断伸长率降低,但不明显;当白炭黑灼烧减量超过1.31%时,硅橡胶混炼过程中易出现结构化;吸油值对硅橡胶混炼胶的性能无明显影响,但会影响混炼胶的结构化。选择比表面积210 m~2/g、灼烧减量小于1.31%、吸油值小于1.90 cm~3/g的白炭黑为填料,可获得加工性能良好的硅橡胶混炼胶。     

不同链结构高填充白炭黑溶聚丁苯橡胶的性能比较

从生胶性能、混炼胶硫化特性以及硫化胶物理机械性能和动态力学性能等方面比较了4种链结构不同的高填充白炭黑溶聚丁苯橡胶,分别为线型(试样A和B)、无规支化(试样C)及星形(试样D)结构。结果表明,填充80份(质量)白炭黑后,试样C的混炼胶门尼黏度最低,正硫化时间最长;在硫化过程中试样D的转矩差最小而试样A的最大;硫化胶中试样D的25%和100%定伸应力、硬度、回弹率及裂口增长最大,而试样B的拉伸强度、扯断伸长率、永久变形率及撕裂强度最大;试样D中的填料聚集和网络化程度较低,滚动阻力低,而试样C的抗湿滑性能较好。     

Synthesis of dysprosium/Mn–Cu ferrite binary nanocomposite: Analysis of structural,morphological, dielectric,and optomagnetic properties

Manganese–copper ferrite (MCFO) and dysprosium (Dy)-doped manganese–copper ferrite nanocomposites (Mn_0.5Cu_0.5Dy_xFe_2−xO₄) (x = 0, 0.05, 0.10, and 0.15) were synthesized by sonochemical method. Crystal structure and the structural parameters of the MCFO were analyzed based on the doping concentration of Dy ion. It was observed that the average crystalline size of the synthesized nanocomposite decreases when the concentration of Dy increases. The existing spherical surface morphology of the MCFO and Dy-doped MCFO nanocomposites were obtained through scanning electron microscopy. In the UV spectrum, the pristine MCFO sample showed an absorbance peak at 743 nm whereas the absorbance values of Dy-doped ferrite nanocomposite considerably shifted (blue) toward a lower wavelength (231–222 nm). The dielectric parameters of all ferrite nanocomposites were studied in the frequency range of 100 Hz to 5 MHz. The dielectric spectrum revealed that dielectric constant and loss tangent decreased with increased doping concentration of Dy ion. The saturation magnetization also changed with Dy doping in MCFO. The impact of Dy on manganese–copper ferrite changed the optical, dielectric and magnetic properties of the prepared binary ferrite nanocomposite, which can be used for microwave-absorbing material applications.     

Mechanical Properties of Compression Molded Banana Pseudo-stem Filled Unplasticized Polyvinyl Chloride (UPVC) Composites

Mechanical strengths of a banana pseudo-stem (BPS) fiber and unplasticized polyvinyl chloride (UPVC) composite were evaluated to assess the possibility of using it as a new material in engineering applications. Samples were fabricated by the compression molding process with reference to the effect of filler loading. The samples were submitted to mechanical tests to measure tensile, flexural, and impact properties of the composites. The nature of adhesion between the matrix and the reinforcement and information relating the structure of mechanical properties can be obtained by scanning electron microscopy (SEM) assessment of the composite fracture surface. The mechanical properties show that the composites did not have good adhesion between filler and matrix; on the other hand, the filler insertion improved the flexural modulus and the material rigidity.     

核壳型纳米粒子合成方法及其性能的研究进展

核壳纳米粒子作为复合纳米粒子一个重要的分支,由于其光、磁和催化等方面的优异性能,近年来引起了人们广泛的关注.本文主要介绍了核壳纳米粒子的制备方法及诸多性能,并对核壳纳米粒子的发展进行了展望.     

单向玻璃纤维-铝合金层板的几种力学性能研究

本文用实验方法研究了单向玻璃纤维-铝合金层板的拉伸性能、疲劳性能和冲击性能。利用金属体积分数理论验证了这类层板的拉伸性能。通过对其疲劳性能的实验研究，发现裂纹扩展速率的大小及刚度的下降与加载的最大循环应力密切相关的规律。实验发现该层板具有比铝合金好得多的冲击性能。     

TMPTMA在硅橡胶中的应用研究

研究了助交联剂三羟甲基丙烷三甲基丙烯酸酯(TMPTMA)对硅橡胶硫化性能、力学性能、低温性能和粘接性能的影响。结果表明,加入少量TMPTMA能改善硅橡胶的硫化特性和工艺性,提高硫化胶的硬度,降低硅橡胶的结晶温度,并有效提高硅橡胶与金属的粘接强度;但TMPTMA用量超过一定数值后,由于TMPTMA部分自聚合,在硅橡胶内形成一定的交联网络,造成两相界面粘接力变差,致使硅橡胶的拉伸强度降低。当TMPTMA用量为1份时,硅橡胶具有最佳的综合性能。     

聚氨酯种类对机械性能以及阻尼性能影响研究

分别以聚四氢呋喃醚二醇(PTMEG)、聚氧化丙烯二醇(PPG-1000)为软段,以二苯基甲烷二异氰酸酯(MDI-50、MDI-100LL),以及扩链剂1,4-丁二醇(BDO)、三羟甲基丙烷(TMP)为硬段,采用预聚体法制备了聚氨酯弹性体。并系统研究了聚氨酯体系中各组分的种类对材料机械性能和阻尼性能的影响。     

A new precursor to lightweight porous Si–Al–O–B ceramics with enhanced microwave transmissivity

Nowadays, complicated preparation processes and harsh sintering conditions wave transparent ceramics limit its further development. To solve this problem, we explore a promising precursor by adopting a polymerization-pyrolysis method to prepare porous Si–Al–O–B ceramics at a mild sintering condition (1000 °C). The porous Si–Al–O–B ceramics exhibits enhanced wave transparency at 10–16 GHz with a low dielectric constant (<3), a low loss angle tangent value (<0.01), and simultaneously, a relative high flexible strength of 82 MPa. According to the results of the XRD and FTIR analysis, porous Al₄B₂O₉ crystallization dispersed in the amorphous SiO₂ matrix constructs the main phases of the products. The changes of Al and B elements are confirmed to have an effect on the phase compositions and micro structure of the composite ceramics, which obviously affect the mechanical and dielectric properties of the derived ceramics. The as-prepared porous Si–Al–O–B ceramics could be a potential candidate for next generation electronic window materials due to its low dielectric constant and loss angle tangent value, as well as high flexible strength.     

Effects of support and additive on oxidation state and activity of Pt catalyst in propane combustion

The effects of support and additive on the oxidation state and catalytic activity of Pt catalyst in the low temperature propane combustion were systematically investigated on Pt/MgO, Pt/Al₂O₃ and Pt/SiO₂–Al₂O₃. The catalytic activity varied much with both support materials and additives. The catalyst on the more acidic support showed higher activity, and the catalytic activity on every support materials increased as the electronegativity of additives increased, while some additives decreased the activity. The oxidation state of platinum, estimated by white line intensity of Pt L_III-edge XANES spectrum, also varied with the support and additives, and additives with higher electronegativity greatly prevented the platinum from its oxidation under oxidising atmosphere. Among almost all the catalysts with various supports and various additives, a clear relationship was observed between the oxidation state of platinum and the catalytic activity; the more metallic platinum showed higher activity. Thus, it was concluded that the total electrophilic/electrophobic property derived from those of the support and additive controls the oxidation state of platinum, which intensively affects the catalytic activity; i.e. higher electrophilic property provides less oxidised platinum, resulting in high catalytic activity. The mechanism of this effect was also discussed on the basis of thermochemical data, and it was proposed that the electrophobic materials promote the noble metal oxidation since the noble metal oxo-anion such as PtO^δ− is more stabilised with electrophobic cation.     

聚丙烯基抗菌塑料的制备与性能研究

利用熔融挤出共混技术制备了聚丙烯(PP)基抗菌塑料。研究了抗菌母料Antim-PP对PP的抗菌性能和力学性能的影响。结果表明,当抗菌母料与PP的质量比为4:100时,抗菌PP塑料对大肠杆菌的抗菌率大于99%,抗菌母料的加入使共混物的冲击性能有明显改善,其他力学性能基本不受影响。