PPS/CaSO4晶须/GF复合材料的研究

采用自制偶联剂对硫酸钙(CaSO4)晶须进行表面处理,研究了聚苯硫醚 (PPS)/CaSO4晶须复合材料的制备方法,并对复合材料的力学性能和结晶性能进行了表征,研究了玻纤增强PPS/CaSO4晶须复合材料的力学性能和微观结构.结果表明,CaSO4晶须加入量及复合材料制备工艺对复合材料的力学性能有较大的影响;随晶须用量的增加复合材料的力学性能和结晶性能都呈先增后降的趋势.CaSO4晶须增强PPS不能作为替代玻璃纤维增强PPS材料,引入玻璃纤维,材料的力学性能将得到很大的提高.     

剑麻纤维与晶须混杂增强聚丙烯复合材料

采用熔融共混和注塑成型方法制得了剑麻短纤维(SF)和CaSO4晶须混杂增强聚丙烯(PP)复合材料，研究了复合材料的热性能、微观结构和力学性能。结果表明，晶须提高了复合材料的热稳定性，阻碍了PP的结晶，降低了复合材料中PP相的结晶度和结晶速率；SF和晶须提高了复合材料的模量和韧性，但由于混杂增强复合材料弱界面键合的制约，晶须的高强性能并没有在复合材料中充分表现出来。     

PPS/GF/晶须复合材料流变性能

利用熔融共混法制备了玻璃纤维(GF)增强聚苯硫醚(PPS)复合材料.采用毛细管流变仪对PPS/GF以及PPS/GF/CaSO4晶须复合材料的流变行为进行了表征.结果表明,PPS/GF复合材料的黏度随着剪切速率的增大而逐渐降低,呈现出明显的"剪切变稀"行为.随着GF用量的增加,PPS/GF复合材料的黏度逐渐升高,非牛顿指数n值逐渐降低.晶须用量为5份时,PPS/GF/CaSO4晶须复合材料的黏度最低,结构黏度指数较低,纺丝加工性能较好.复合材料的黏度随晶须用量的继续增加而增加.在310~315℃时复合材料的结构黏度指数下降幅度最小,表明该温度范围熔体流动最稳定.     

CSW/TPU复合材料的制备及性能

采用熔融共混技术制备了硫酸钙晶须(CSW)填充改性的热塑性聚氨酯弹性体(TPU)复合材料(CSW/TPU),讨论了CSW对复合材料的力学性能、加工性能和热性能的影响。结果表明,CSW含量对CSW/TPU复合材料的力学性能有明显影响,CSW质量分数为5.0%时,CSW/TPU复合材料的综合力学性能较好。转矩流变仪分析表明,CSW的加入使得复合材料的加工性能变好。热重分析发现,CSW的加入并未对TPU的分解温度产生明显影响。     

高性能浇注型聚氨酯弹性体的动态性能研究

通过高性能浇注型聚氨酯弹性体的合成，研究了二异氰酸酯结构、多元醇结构对浇注型聚氨酯弹性体动态性能的影响，结果表明，异氰酸酯基团含量增加，聚氨酯弹性体的硬度、撕裂强度和耐热性提高。     

二氧化硅气凝胶改性热塑性聚氨酯弹性体材料的制备及性能研究

采用预聚体法制备了聚酯型热塑性聚氨酯弹性体(TPU)/二氧化硅气凝胶复合材料,研究了不同二氧化硅气凝胶用量对复合材料力学性能、耐水解性能与高温稳定性等性能的影响,并对复合材料的结构进行了分析与表征。结果表明:加入二氧化硅气凝胶后,复合材料的力学性能有所提高,耐水解性能较TPU基体有所提升,复合材料的导热系数降低。热重分析测试表明:加入二氧化硅气凝胶提高了复合材料的高温稳定性。扫描电镜测试表明:二氧化硅气凝胶在TPU基体中分散良好。     

钛酸钾晶须填充新型聚芳醚酮的性能

用溶液共沉析的方法制备了含二氮杂萘结构的聚芳醚酮／钛酸钾晶须复合材料，晶须表面用偶联剂处理。研究了复合材料的拉伸强度，冲击强度，弯曲强度，形态及热性能，结果表明，复合材料的冲击强度和弯曲强度随晶须含量的增加而增高，而拉伸强度却呈下降趋势，热重分析显示，随晶须含量的增加，复合材料的热稳定性提高。     

硅灰石晶须/MCPA6复合材料的结构与性能

采用阴离子聚合制备了硅灰石晶须/浇铸尼龙6(MCPA6)复合材料,探讨了硅灰石晶须对复合材料微观结构、性能的影响以及增强机理。FTIR结果表明硅灰石晶须加入未改变MCPA6的化学结构,复合材料属于物理共混改性。SEM分析显示硅灰石晶须的用量决定了两相界面的黏结状态;当硅灰石晶须质量分数为5%时,晶须能均匀地分散在复合材料中,界面相容性好,此时复合材料综合性能最佳。与纯MCPA6相比,硅灰石晶须/MCPA6复合材料的拉伸强度、弯曲强度和冲击强度分别提高55.3%、71.5%和58.5%,吸水率降低36%。     

减磨耐磨聚氨酯复合材料摩擦性能的研究

通过聚醚多元醇与甲苯二异氰酸酯反应，合成了端异氰酸酯基预聚体；在预聚体中加入一些具有减磨功能的添加剂进行物理共混，并用芳香族二胺为固化剂硫化成型，制得减磨耐磨聚氨酯复合材料。着重探讨了不同聚氨酯胶料、减磨添加剂的种类和用量等因素对该复合材料力学性能和耐磨性能的影响。结果表明：聚氨酯胶料的结构不同对弹性体力学性能有不同程度的影响；由相同原料制得的减磨聚氨酯复合材料，硬度越高，磨耗量越小；有机硅类和有机蜡类添加剂与聚氨酯胶料相容性较好，所得的复合材料外观清透，质量损失和体积损失都相对较小，而含氟材料和无机填料添加剂与胶料相容性较差，体系发生明显的相分离；有机硅类添加剂用量宜在０．５％～１．５％范围。     

多维无机材料复合改性PVC的性能研究

研究了一维CaSO4晶须、二维滑石粉、三维重质CaCO3和零维纳米CaCO3对复合改性聚氯乙烯(PVC)的力学性能影响,分析了改变多维无机材料的比例对改性PVC的性能影响。结果表明,与其他无机材料复合改性PVC相比,一维CaSO4晶须、二维滑石粉、三维重质CaCO3复合改性PVC的综合性能最好,加工性能最佳;一维CaSO4晶须和零维纳米CaCO3添加量为10份时复合改性PVC的冲击性能达到最大值;一维CaSO4晶须、三维重质CaCO3、二维滑石粉按照4/2/1的质量比复合改性PVC时综合性能最佳。     

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。