空心玻璃微珠改性环氧树脂的制备及其性能研究

以双酚F环氧树脂为基体,以空心玻璃微珠为填料,制备环氧树脂绝缘复合材料。用硅烷偶联剂KH-570对空心玻璃微珠进行表面改性,并研究改性后的空心玻璃微珠对复合材料力学性能、热机械性能以及电绝缘性能的影响。实验结果表明:随着填料含量的增加,力学性能表现出先增加再降低的趋势,并在空心玻璃微珠含量为4%时,性能达到最优;热机械性能和介电性能均随填料含量的增加而呈现降低的趋势,并在空心玻璃微珠含量为8%时,介电常数最低。     

空心玻璃微珠/环氧树脂复合材料制备及其性能研究

研究了空心玻璃微珠/环氧树脂复合材料制备工艺、配方设计,并对材料的密度、力学性能、表面改性剂、粒径匹配、热性能、介电性能和微观形貌进行了实验研究.结果表明:空心玻璃微珠/环氧树脂复合材料密度在0.28～0.8g/cm3之间可调,抗压缩强度达到4.5MPa～120MPa,空心玻璃微珠表面改性剂的加入,明显提高了复合材料的机械性能,在600～9000MHz频率条件下,其介电性能基本不随频率而变化,介电常数为2.01～2.05,介电损耗角正切为2.57×10-3-2.80×10-3,空心玻璃微珠/环氧树脂复合材料具有较高的使用温度,扫描电镜表明表面改性剂改善玻璃微珠的浸润性,并且验证了空心玻璃微珠级配理论.     

空心玻璃微珠表面改性对环氧树脂复合材料性能影响研究

针对空心玻璃微珠填充环氧树脂存在的问题,采用硅烷偶联剂改性空心玻璃微珠填充环氧树脂制备复合材料,通过含水率、吸油值、力学性能等测试考察了硅烷偶联剂对空心玻璃微珠性能及复合材料力学性能的影响。研究发现,硅烷偶联剂通过改变空心玻璃微珠表面性能,减缓空气中水分的侵入;KH591对空心玻璃微珠的表面包覆效果最佳,且KH591改性空心玻璃微珠填充环氧树脂制备的复合材料综合性能最佳——拉伸强度为56.8MPa、弯曲强度为60.05MPa。     

空心玻璃微珠填充MC尼龙复合材料的研究

对空心玻璃微珠填充铸型(MC)尼龙进行了系列研究,考察了空心玻璃微珠含量、粒径及表面处理对MC尼龙性能的影响。结果表明,空心玻璃微珠改性MC尼龙复合材料的物理性能和力学性能优良,当加入10％表面处理的空心玻璃微珠时,制品的收缩率下降,热变形温度提高20℃以上,制品具有填料分布均匀、外观光泽优良等优点。与未处理的空心玻璃微珠相比,填充经表面处理空心玻璃微珠的复合材料拉伸强度、弯曲强度、断裂伸长率分别提高了15．7％、12．2％和246％。空心玻璃微珠的粒径愈小,复合材料的力学性能愈好。一定用量的玻璃微珠填充MC尼龙不仅可以使材料保持较好的力学性能和耐热性能,而且能够降低MC尼龙复合材料的成本。     

BMI树脂基轻质耐压复合材料的制备及性能研究

采用空心玻璃微珠填充改性双马来酰亚胺(BMI)树脂,研究了玻璃微珠用量和粒径以及表面处理的玻璃微珠,对材料压缩性能以及吸水性的影响。结果表明小粒径(10μm)较大粒径(70μm)玻璃微珠填充改性双马来酰亚胺树脂的压缩强度降低缓慢,经表面处理后可获得最佳效果。少量地加入玻璃微珠可降低环氧树脂的吸水性,但随着玻璃微珠含量的增大,体系的吸水性会随之增加。当玻璃微珠含量为30%时,复合材料密度降至0.74gcm3,压缩强度仍可以达到68.5MPa。     

偶联剂处理玻璃微珠对环氧树脂增韧效果明显

环氧树脂具有优良的粘接性能、力学性能、耐化学品性能、电气性能、工艺性能等，因而应用极为广泛，但纯环氧树脂固化物脆性较大是其软肋，限制了它的更广应用。国内外已研究成功很多增韧方法，其中之一就是刚性粒子增韧，武汉理工大学将空心玻璃微珠（深圳空微特种材料有限公司产品）经偶联剂KH-550处理后，借助超声波振动使处理后的空心玻璃微珠在环氧树脂体系中均匀、稳定分散，改善了与环氧树脂的相容性，结合更紧密，明显提高了环氧树脂体系的力学性能。结果表明，当添加处理的空心玻璃微珠质量分数为3％时，     

改性空心玻璃微珠/环氧树脂复合材料力学性能研究

采用偶联剂对玻璃微珠表面进行改性处理,借助超声波振动,使改性空心玻璃微珠在环氧树脂中均匀、稳定分散,增强了玻璃微珠与环氧树脂之间的相容并探讨了改性空心玻璃微珠对环氧树脂力学性能的影响。结果表明,复合材料中改性空心玻璃微珠添加质量分数为3%时,其拉伸强度达到最大值68.54 MPa,与空白样相比提高了20.3%;冲击强度达到最大值24.42 kJ/m2,比纯环氧树脂提高了166%;KIC(断裂韧性)达到最大值2.338 MPa/m2,是空白试样的2.27倍,增韧效果较为明显。     

空心玻璃微珠增强聚丙烯材料的性能研究

研究了空心玻璃微珠填充改性聚丙烯的力学性能和热性能。结果表明,空心玻璃微珠的加入,可使聚丙烯的密度、拉伸强度、冲击强度等力学性能下降,弯曲强度、维卡软化温度呈上升趋势。     

新型橡胶填料--空心玻璃微珠

空心玻璃微珠对我国橡胶工业而言，还是一种新填料。研究空心玻璃微珠的表面特性和表面处理效果，探讨了空心微珠在炭黑增强橡胶中的应用。结果表明：空心玻璃微珠表面的羟基含量很低，含水量很小，不利于进行改性程度高的表面处理。空心玻璃微珠的粒径有一定的分布。使用硅烷偶联剂进行表面处理后，能够使微珠的表面由亲水变为亲油，并在一定程度上提高其补强性能。空心微珠可以在完全不改变原有配方的基础上，进行较大量填充。单独使用不如与炭黑、白炭黑并用，复合材料的主要优势在于：成本较大幅度地下降，各项力学性能保持较好，随微珠用量的增加，加工性能和产品的外观进一步改善。     

低密度BMC复合材料性能的研究

研究了四种不同种类的空心玻璃微珠的加入对团状模塑料(BMC)密度及性能的影响,观察空心玻璃微珠在BMC中的分散及破损情况以及空心玻璃微珠S38含量的变化对BMC密度及性能的影响。结果表明,随着微珠含量的增加密度及拉伸强度逐渐下降;微珠含量为5%时弯曲及冲击强度达到最大值。研究微珠的表面处理对BMC性能的影响,结果表明,微珠的表面处理能有效提高BMC的力学性能。     

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.     

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。     

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.     

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。