铁系3,4-聚异戊二烯橡胶的性能

考察了以异辛酸铁、三异丁基铝和偶氮二异丁腈催化剂在己烷中50℃下制备的3,4-聚异戊二烯(3,4-IR)[3,4( 1,2)结构质量分数约为50%,ML110 04℃为52,玻璃化转变温度为-21.6℃]与SBR或NR质量比为20/80组成的共混胶的力学性能和粘弹性能。SBR/3,4-IR和NR/3,4-IR共混胶与SBR或NR相比,其拉伸强度和扯断伸长率有所下降,回弹性明显降低,但硬度基本不变。根据0℃和60℃下的损耗因子tanδ值可知,3,4-IR可明显提高SBR或NR硫化胶的抗湿滑性能,并使滚动阻力有所降低。     

P(SBR/NR/HAF)并用胶的性能

在SBR胶乳／NR胶乳共混的基础上，采用凝聚共沉法制备高耐磨炭黑（HAF）填充型粉末丁苯橡胶／天然橡胶并用胶[P(SBR/NR/HAF)]。研究了SBR／NR并用比、制备工艺等对P（SBR／NR／HAF）并用胶的混沌流变性能和物理机械性能的影响，并与块状SBR／NR／HAF并用胶进行了比较。研究表明，与SBR／NR／HAF相比，P（SBR／NR／HAF）的表观剪切粘度在SBR用量小于50份时对混炼时间的依赖性较低，而在SBR用量大于50份后对混炼时间具有更高的依赖性；P（SBR／NR／HAF)硫化胶 拉伸强度在整个并用范围内对SBR／NR并和比不敏感；采用胶乳预混合的工艺制备的P（SBR／NR／HAF）具有较好的物理机械性能。     

DCPD树脂对NR/SBR共混胶性能的影响

采用新型DCPD树脂改性NR/SBR共混胶。结果表明,DCPD树脂对NR/SBR共混胶具有一定的补强作用,即撕裂强度明显升高;DCPD树脂可改善硫化胶抗硫化返原性、耐热空气老化性以及耐磨耗指数;动态条件下,低于50℃时DCPD树脂对损耗因子影响不明显;高于50℃时,损耗因子稍有增大;DCPD树脂还可提高NR/SBR共混胶储能模量。     

纳米SiO2改性NR/SBR共混胶的结构与性能研究

研究了纳米SiO2加入方式及用量对NR/SBR共混胶的正硫化时间、力学性能的影响,并研究了纳米SiO2改性前后共混胶的耐热分解性能、耐热空气老化性能及微观形态结构.结果表明:纳米SiO2的加入对共混胶的正硫化时间、力学性能及耐热稳定性能有较大影响;当纳米SiO2加入量为7％(质量分数)并采用NR/SBR共混均匀后先加入纳米SiO2,再加入小料、硫磺的方式制备NR/SBR共混胶时,纳米SiO2通过使NR/SBR共混胶的分散相细化并使共混胶的整体交联密度提高,有效地提高了NR/SBR共混胶的综合力学性能和耐热稳定性能,达到了对NR/SBR共混胶良好的补强改性效果.     

绢云母粉对NR/SBR/BR共混胶热-力学性能的影响

介绍了绢云母粉在NR/SBR/BR,共混胶中的应用研究,探讨了绢云母粉对NR/SBR/BR共混胶的硫化特性、共混硫化胶常温及高温力学性能、屈挠性能、耐热老化性能以及热传导性能影响.结果表明;随着绢云母粉用量的增大,NR/SBR/BR共混胶的常温及高温力学性能、屈挠性能、耐热老化性能以及热传导性能都有不同程度的改善.当绢云母粉的用量为30份时,NR/SBR/BR共混胶具有良好的温力学性能、屈挠性能和热传导性能.     

均匀剂在橡胶加工过程中的应用效果

研究了3种国外均匀剂产品40MS,60NS和M40和NR／BR及NR／BR／SBR共混体系中的应用效果。试验结果表明,均匀剂可改善胶料的加工流动性,降低胶料的门尼粘度和混炼功耗,提高混炼胶的相态均匀性,缩短炭黑的混入时间,对硫化胶的物理性能影响不大,相对而言,均匀剂M40对NR／BR和NR／BR／SBR共混体系的综合性能影响效果最好,当用量为3份时可达到加工性能和使用性能的最佳平衡。     

Si 69在炭黑填充NR/BR/NBR共混物中的应用

在炭黑填充NR／BR／NBR共混物中加入Si 69，共混物硫化速度降低、物理机械性能提高；Si 69用量为4份时，硫化胶的综合性能最佳。将140℃下用Si 69处理30min后的炭黑加入NR／BR／NBR共混物，可降低硫化胶在65℃下的tan 6值，表明材料的滚动阻力下降。     

均匀增粘剂H-501对NR/SBR/BR性能的影响

研究均匀增粘剂H—501和NR／SBR／BR并用比对胶料物理性能的影响。结果表明，均匀增粘剂H—501有利于提高NR／SBR／BR混炼胶的分散均匀性，能提高并用胶硫化胶的拉伸性能、耐疲劳性能和耐磨性能，而且不影响胶料的硫化速度，不降低其老化性能。均匀增粘剂H—501可明显提高NR／SR并用胶，特别是SR用量较大的并用胶硫化胶的综合性能。     

纳米三氧化二铝增强天然橡胶/丁苯橡胶并用胶的性能

采用机械混炼法制备了纳米三氧化二铝(Al_2O_3)增强天然橡胶(NR)/丁苯橡胶(SBR)并用胶,研究了纳米Al_2O_3对NR/SBR并用胶的硫化特性、力学性能、耐热性和耐溶剂性的影响。结果表明,当纳米Al_2O_3的用量为4份,并采用NR/SBR与小料共混均匀后再加入纳米与硫黄的方式制备NR/SBR并用胶,可大幅提高NR/SBR并用胶的力学性能。与未增强并用胶相比,采用4份纳米Al_2O_3增强并用胶的100%定伸应力、拉伸强度、撕裂强度和扯断伸长率分别提高了16.0%、296.4%、28.6%和73.3%,耐热性及耐油性也得到显著提高。     

偶联剂改性对磁敏NR/SBR并用胶性能的影响

将NR和SBR与改性羰基铁粉机械共混制备磁敏NR/SBR并用胶,研究偶联剂KH-550,KH-560,KH-570和NDZ-401改性羰基铁粉对磁敏NR/SBR并用胶的物理性能和磁流变效应的影响。结果表明:不同偶联剂改性的羰基铁粉对NR/SBR并用胶性能有一定的影响;采用偶联剂KH-570改性的羰基铁粉填充的NR/SBR并用胶表现出较好的物理性能和磁流变效应。     

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。     

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。     

阻隔性PET/PEN共聚酯的性能研究

对共聚型阻隔聚酯PETNx(x为共聚酯中NDA占羧酸总质量的百分比)的热性能、流变性能和阻隔性能进行了研究。结果表明,PETNx体系属于假塑性流体。PETNx的CO2气体阻隔性优于常规PET;随着PETNx中NDA含量的增加,共聚物的玻璃化温度呈线性增高。     

丁腈橡胶的伏安特性与功率特性的研究

本文对乙炔碳黑填充丁腈橡胶（NBR）的伏安特性及其功率特性进行了研究,分析了丁腈橡胶在交、直流电场下的导电机理,并对环境温度变化时的丁腈橡胶的功率及功率与电压的变化规律提出了相应的关系式,同时对导电丁腈橡胶的物理机械性能进行了研究与测定。