BPR含量对BPR/SF/PF复合材料摩擦磨损性能和力学性能的影响

将硼酚醛树脂(BPR)与普通酚醛树脂(PF)熔融共混,再加入经过碱处理的剑麻纤维(SF),通过模压成型工艺制备BPR/SF/PF复合材料。利用定速式摩擦试验机和电子万能试验机研究了BPR含量对复合材料摩擦磨损性能及力学性能的影响,采用扫描电镜观察了复合材料磨损表面的形貌。结果表明:在BPR/PF=50/100时,与普通PF/SF复合材料相比,BPR/SF/PF复合材料在300℃下的磨损率降低了42%,冲击强度提高了14%,弯曲强度和弯曲模量分别提高了25%和36%;复合材料磨损面形貌显示,加入BPR后,复合材料由疲劳磨损转变为磨粒磨损。     

表面处理方法对剑麻纤维/酚醛树脂复合材料性能的影响

分别采用碱、硅烷偶联剂、阻燃剂对剑麻纤维(SF)进行表面处理,采用模压成型工艺制备了SF/酚醛树脂(PF)复合材料。研究了SF表面处理方法对SF/PF复合材料的摩擦磨损性能、力学性能、吸水性的影响,借助扫描电镜观察了复合材料磨损面的形貌。结果表明:SF经阻燃剂处理后,SF/PF复合材料的磨损体积为0.00053cm3,比未处理的SF/PF复合材料减少了77.2%;SF经硅烷偶联剂处理后,SF/PF复合材料的冲击强度、弯曲强度分别比未处理的SF/PF复合材料提高18.7%、15.4%,且耐水性也有一定改善。     

SF/PF复合材料冲击性能的研究

研究了剑麻纤维(SF)的表面处理方式、纤维的含量、纤维的长度及与玻璃纤维混杂增强对SF／酚醛树脂(PF)复合材料冲击强度的影响，借助SEM观察复合材料的冲击断面，进行了微观结构分析。结果表明，SF经过碱处理后复合体系的冲击强度提高了34％，当SF的质量分数为40％、长度为6ram时，SF／PF复合材料冲击强度达到最大值，当SF与玻纤质量比为1：1时，复合材料冲击强度出现了混杂效应。     

GO/PF原位复合材料的摩擦磨损性能及力学性能

采用改进的Hummers法制备氧化石墨烯(GO),并与酚醛树脂(PF)进行原位聚合,将原位聚合树脂与固化剂、填料等通过辊炼、模压成型制备GO/PF原位复合材料.研究GO的含量对GO/PF原位复合材料的力学性能及摩擦磨损性能影响,使用扫描电子显微镜(SEM)观察复合材料的磨损面形貌.研究结果表明,GO通过原位聚合能在一定程度上提高复合材料的力学性能、摩擦磨损性能,当GO质量分数为0.25％时,GO/PF原位复合材料的冲击强度提高了18.6％,在250℃和300℃下,GO/PF原位复合材料的体积磨损率分别降低了20.0％和15.6％.     

环氧液晶/酚醛树脂复合材料的摩擦磨损性能研究

利用自行合成的端基为环氧基的热致性环氧液晶(LCE)与酚醛树脂(PF)通过熔融挤出进行原位复合制备了LCE/PF复合材料。研究了LCE含量对LCE/PF复合材料力学性能、硬度及摩擦性能的影响,使用扫描电子显微镜(SEM)观察了复合材料的磨损面形貌,分析了复合材料的摩擦磨损机理。研究结果表明:LCE含量为2.5%时,摩擦系数比未加LCE的稳定,力学性能也有所提高;在各温度下,LCE含量为7.5%的复合材料的体积磨损率比未加LCE的复合材料的小达,到了GB 5763—2008的要求。     

纳米SiO_2/UP复合材料的力学性能和热性能研究

通过熔融共混、模压成型方法,制备了纳米二氧化硅(SiO2)/不饱和聚酯(UP)复合材料,研究了纳米SiO2含量对复合材料的力学性能、动态力学性能和热膨胀性能的影响,采用SEM观察了复合材料的磨损面形貌。结果表明:当纳米SiO2含量为2.5%时,SiO2/UP复合材料的冲击强度和弯曲强度比纯UP分别提高了28.57%、8.43%;当纳米SiO2含量为3.5%时,SiO2/UP复合材料的玻璃化转变温度比纯UP提高了16℃;当纳米SiO2含量为0.5%时,SiO2/UP复合材料的热膨胀系数为41.367×10-6K-1;加入纳米SiO2后,SiO2/UP复合材料的磨损机理主要表现为磨粒磨损和黏着磨损。     

硅藻土/不饱和聚酯复合材料的性能研究

通过原位聚合法制备了硅藻土/不饱和聚酯(UP)复合材料。研究了硅藻土含量对该复合材料力学性能及摩擦磨损性能的影响,并利用扫描电镜(SEM)对磨损面进行观察。结果表明:当硅藻土含量为4%时,硅藻土/UP复合材料的储能模量提高了16.4%;硅藻土含量为3%时,硅藻土/UP复合材料的玻璃化转变温度提高了6℃,冲击强度提高了11.96%,总磨损量降低了17.5%;硅藻土含量为2%时,硅藻土/UP复合材料的弯曲强度提高了23.2%。     

表面改性对酚醛树脂/氧化石墨烯复合材料的力学性能与摩擦性能的影响

采用硅烷偶联剂KH550对氧化石墨烯(GO)进行表面改性,制备改性的氧化石墨烯(MGO),采用FTIR和XRD对MGO进行结构表征,通过共混、混炼、模压成型工艺制备酚醛树脂(PF)/MGO复合材料,研究GO的表面改性对PF复合材料的力学性能、动态力学性能和摩擦性能的影响,采用扫描电子显微镜(SEM)对复合材料的磨损表面进行形貌分析。结果表明:GO的表面改性对提高PF复合材料的力学和动态力学性能、摩擦学性能具有明显效果,相比于未改性的PF/GO复合材料,其冲击强度提高了24.32%,弯曲强度提高了10.95%,弯曲模量提高了21.21%,松弛模量提高了42.22%,形变率降低了40.79%,同时改性的PF/MGO复合材料具有较高的摩擦系数和磨损率;扫描电镜观察结果显示,复合材料的磨损表面显得平整、光滑。     

萘酚对环保型酚醛树脂的改性研究

对萘酚改性环保型酚醛树脂(PF)进行了研究,通过差示扫描量热(DSC)、热重分析(TGA)仪和扫描电子显微镜(SEM)等对改性前后PF的耐磨、耐热性能及力学性能进行了对比.结果表明,改性后的PF耐磨性、耐热性和力学性能均比未改性时有很大程度的提高.萘酚改性的PF可将树脂的质量磨损损失降低54.9%,质量磨损损失率降低56.0%.改性PF的初始失重温度提高70～80℃,可将树脂在600℃时的残余量提高37%.改性后PF的拉伸强度、弯曲强度和冲击强度分别比未改性时提高了519.7、360.4 MPa和43.2 kJ/m~2.     

碳纳米管对酚醛树脂/碳纤维复合材料力学性能的影响

利用碳纳米管(CNTs)对酚醛树脂(PF)进行改性,研究了CNTs含量对PF/碳纤维(CF)复合材料力学性能的影响。研究表明,CNTs能够明显提高PF/CF复合材料的力学性能,当CNTs的含量为0.5%时,复合材料的弯曲强度达到最大值(891.8MPa),与未加入CNTs时相比提高了168.4MPa,而弯曲弹性模量降低了9.5GPa;当CNTs的含量为1.5%时,复合材料的压缩强度、层间剪切强度、冲击强度均达到最大值,与未加入CNTs时相比,分别提高了10.4%、79.2%、71.9%。     

SF型推动棒式篦冷机生产实践

1基本情况介绍 冀东水泥磐石有限公司2002年4月新建一条3000t/d熟料的PC窑熟料生产线，自2003年4月投产以来．运转顺利，已生产熟料260多万吨，稳产高产，经济效益显著。     

Studies of electrospun regenerated SF/TSF nanofibers

The Bombyx mori silk fibroin/Tussah silk fibroin (SF/TSF) nanofibers with diameters between 300 and 3500 nm were prepared by electrospinning with the solvent HFIP. The average diameters of SF/TSF blend fibers increased from 404 to 1977 nm, with the increase of SF content in blend solutions, and the relationship between the average diameters of SF/TSF and SF content was proved to be linear correlation. Results from FTIR, TG-DTA and X-ray diffraction showed that the electrospun fibers were mainly β-sheet structure and, heterogeneous micro-structures. In particular, the presence of two different endothermic peaks at 300 and 360 °C in the TG-DTA curves may be ascribed to the thermal decomposition of SF and TSF. These results suggested that SF and TSF were still immiscible even dissolved in hexafluoroisopropanol (HFIP) after electrospinning and ethanol treatment. Moreover, the thermal decomposition temperature and enthalpy were improved with the blend of SF and TSF, else the SF/TSF nanofibers' moisture absorption was higher than the pure SF or TSF nanofibers. To study the cytocompatibility and cell behavior on the SF/TSF nanofibers, MSCs, VECs, and Neurons were seeded onto the nanofibers. Results indicated that the SF/TSF nanofibers promote cell attachment and spreading, suggesting that these nanofibers could be a candidate scaffold for blood vessel and nerve injury recovery.     

丝素/聚乳酸静电纺丝的研究

以具有一定生物活性、细胞黏附性能好的丝素蛋白与降解性能优良的聚乳酸复合,以静电纺丝方法形成20%丝素与80%聚乳酸的丝素/聚乳酸共混纤维非织造网。通过扫描电子显微镜研究其形态,X-射线衍射、红外光谱等分析研究其聚集态结构变化。研究表明:丝素/聚乳酸静电纺的纤维直径与电压、接收距离大小和后处理方法有关;不同后处理方法对丝素/聚乳酸静电纺纤维的结晶结构有较大影响。     

端羧基超分散剂对剑麻纤维/聚丙烯性能的影响

采用自制端羧基超分散剂(ECH)改性剑麻纤维(SF)/聚丙烯(PP)复合材料,探讨了ECH的使用对SF/PP复合材料的力学性能、热力学性能和结晶性能的影响,并采用扫描电镜(SEM)观察复合材料的冲击断面形貌。结果表明,经ECH改性后的SF/PP复合材料的冲击强度、弯曲强度分别比未改性的复合材料提高了67.3%和21.0%,复合材料的热稳定性、PP相的结晶速率和结晶度有所提高,但晶态结构仍是典型的α晶型,ECH的加入使得复合材料的储能模量提高,损耗因子降低。     

活性炭吸附剂在六氟化硫生产中的应用

简要介绍了六氟化硫生产中活性炭吸附剂的吸附特性和使用情况，提出了活性炭吸附剂的再生方法和利用活性炭回收六氟化硫的方法。结果表明，活性炭吸附剂可以较好地吸附粗六氟化硫中微量杂质，如SF4，C2F6，SO2F2，SOF2，C3F8等，也能采用合适的方法在180～200℃下活化再生，重复使用。并利用其对六氟化硫选择吸附的特性回收生产中放空的六氟化硫气体。     

Degradation of polymers subjected to radio-frequency discharges in SF6

Studies were conducted on the degradation reaction of polyethylene, poly(tetrafluoroethylene), and an expoxy resin resulting from the action of a 13.56-MHz radio-frequency (rf) discharge in SF₆. The curves showing the temperature variations of the samples during the experiment suggest that this degradation process occurs in two distinct stages: in the first, the heat released by the electric discharge causes the thermal degradation of the polymers, whereas in the second, the volatile degradation products react in the gas phase with the excited SF₆. Analysis of the reaction products shows consistency with this two-step degradation model. The main degradation products have been identified as C₂H₂, C₂H₄, SOF₂, and CS₂ in the case of polyethylene; as CF₄, C₂F₄, and SOF₂ in the case of poly(tetrafluorethylene); and finally as CO₂ and SOF₂ in the case of the epoxy resin. Furthermore, it is interesting to note the formation of polymers of the di(trifluoromethyl) polysulfane type, CF₃-S_n-CF₃, among the reaction products. The more volatile members, n = 2, 3, and 4, were identified by mass spectrometry, whereas the heavier members, identified by infrared spectrophotometry, often took the form of a whitish powder deposited on the walls of the reactor.     

CW CO2-Laser SF6-Photosensitized Pyrolysis of Tetralin

CW CO₂ laser photosensitized (SF₆) pyrolysis of tetralin proceeds mainly via dehydrogenation channel affording 1,2-dihydronaphthalene and naphthalene. Less important ring cleavage products are indene, styrene, ethylbenzene, toluene, and benzene, together with ethylene and methane. No occurrence of polyaromatics and high yields of ethylene compared to methane are the features differing this process from high temperature conventional pyrolysis.     

Selective adsorption of SF6 in covalent- and metal-organic frameworks

Sulfur hexafluoride (SF₆) is an extremely severe greenhouse gas. It is an urgently important mission to find excellent candidates for selective adsorption of SF₆, in order to reduce the emission of SF₆ facilities. Here, we adopt the molecular simulation method to systematically explore the selective adsorption of SF₆ in 22 kinds of representative covalent-and metal-organic frameworks. Results indicate that COF-6 is a promising candidate for the SF₆ adsorption at low pressure P<20 kPa because of its small pore size, while MOF-180 and PAF-302 are excellent candidates at high pressure P=2×10³ kPa due to their large Brunauer-Emmett-Teller specific surface area (BET-SSA) and pore volumes. For the two cases of the power industry (X_SF6=0.1) and the semiconductor industry (X_SF6=0.002) environments, COF-6 and ZIF-8 are fairly promising candidates for selective adsorption of SF₆ from the SF₆/N₂ mixtures, because they not only present the high selectivity, but also the large adsorption capacity at ambient environment, which can be considered as potential adsorbents for selective adsorption of SF₆ at ambient conditions.