氧化处理对煤沥青基中间相炭微球自烧结炭块性能的影响

采用氧化处理得到自烧结性良好的中间相沥青炭微球（MCMB），通过热压成型、炭化等工艺制备了高性能的各向同性炭块，经300℃氧化45min后的中间相炭微球热压成型后1000℃炭化1h制得的炭块密度为1.64g/cm^3、弯曲强度达99.5MPa，详细研究了不同氧化温度和时间对各向同性炭块的密度，弯曲强度、体积收缩率、断面形态等的影响，元素分析、XPS等测试分析结果表明：随着氧化程度的加深，MCMB中氧含是逐渐增加，H、C含量逐渐降低，H/C比也逐渐降低，微球中的塑性组分β树脂被氧化成羟基、羰基、羧基等含氧官能团，微球的芳香度增加，从而降低了中间相沥青炭微球的塑性流动性。     

烯丙基COPNA-BMI树脂微球的制备及表征

以烯丙基缩合多核芳烃-双马来酰亚胺(COPNA-BMI)预聚树脂为原料、以硅油为分散和导热介质,通过悬浮聚合法制备烯丙基COPNA-BMI树脂微球。采用SEM研究树脂微球的形态;采用FT-IR研究树脂微球悬浮聚合前后官能团的变化;采用TG-DTG和SEM研究树脂微球的耐热性和炭化形态。研究表明,烯丙基COPNA-BMI树脂微球具有很好的球形和表面光洁度,其粒径主要分布在10μm～20μm之间;经过悬浮聚合后,烯丙基COPNA-BMI树脂碳碳双键的特征吸收峰消失;该树脂微球具有优良的耐热性,其炭化产物是具有很好球形度的炭微球。     

棉纤维在亚临界水液中炭化形成炭微球

为了寻找一种废旧棉纤维的高效再利用方法,从棉纤维的化学结构着手,结合亚临界水的特殊性质,采用水热法使棉纤维炭化生成附加值较高的炭微球。探讨棉纤维在亚临界水中炭化成球的最优条件,并分析棉纤维炭化的反应过程及水热产物的表面物理结构和微观化学组成。结果表明,棉纤维在280℃,10 h,20 g/L条件下,炭微球的形貌最佳,含碳量达到74.99%,粒径为0.8~3μm。水热产物主要以无定形碳结构形式存在,且含有大量的芳香环结构和脂肪族基团,具有较强的亲水性,表面C/O质量比高于水热产物平均C/O质量比。棉纤维的炭化主要是经水解,裂解,聚合、凝结、芳香化、胶体作用而形成。     

β树脂含量对高密度各向同性炭性能的影响

以不同β树脂含量的中间相沥青炭微球（Mesocabon microbeads,MCMBs）为原料制备高密度各向同性炭块，通过TGA，SEM，Interon等分析方法系统地研究了β树脂含量对炭块力学性能和断面形态的影响，分析了中间相沥青炭微球的自烧结机理，结果表明：由中间相沥青炭微球热压得到的生坯的炭化过程分为两个不同的阶段，塑性烧结和固相炭化：β树脂含量对最终炭化制品的性能影响显著，炭化后炭块的密度，弯曲强度等性能均随β树脂含量的增加先增加后降低，在β树脂含量为8.9wt%时出现最大值。     

N-PMI改性酚醛树脂微球的制备及表征

以N-苯基马来酰亚胺(PMl)改性酚醛树脂为原料、以硅油为分散和导热介质,采用悬浮聚合法制备单分散性较好的树脂微球.采用扫描电镜(SEM)研究炭化前后树脂微球的形态;采用热重分析(TG-DTG)研究了N-PMI改性酚醛树脂的耐热性;采用红外光谱(FT-IR)研究不同炭化温度树脂微球官能团的变化.研究表明,N-PMI改性...     

废弃棉纤维、粘胶纤维和微晶纤维素水热炭化制备炭微球的对比研究（英文）

选择废弃棉纤维和粘胶纤维两种纺织纤维作为水热炭化原料,并以微晶纤维素为模型底物进行对比,研究原料结构对水热炭化条件及产物的影响。结果表明,高结晶度的棉纤维(60.35%)和微晶纤维素(60.24%)制备炭微球的最佳条件分别是330℃,6 h,0.15%CuSO_4和310℃,6 h,0.10%CuSO_4,而低结晶度(34.31%)的粘胶纤维的最佳条件为260℃,8 h。结晶度越低,水热炭化条件越温和,而聚合度对其影响不显著。采用SEM、XRD、FTIR、TG和EDS对炭化产物进行表征,结果表明,不同原料合成的炭微球具有类似的无定型结构和丰富的官能团,但棉纤维和微晶纤维素合成的炭微球具有更高的碳含量和热稳定性,这可能是更高的水热炭化温度所致。因此,纤维素结晶度是影响其水热炭化合成炭微球的重要因素。     

酵母基多孔炭微球的热裂解制备及其吸附性能研究

以氯化锌为活化剂,采用热裂解酵母法制备了多孔炭微球。用FE-SEM、XRD、TG-DTA表征了炭微球的物化结构,测试了炭微球的极性和吸附性能。FE-SEM结果表明多孔炭微球为椭球状,长度为(2.3±0.50)μm,宽度为(3.5±0.45)μm,分散度好。XRD结果表明多孔炭微球为无定形炭。热重分析监控了酵母的转变过程。FT-IR分析表明多孔炭微球的形成与表面化学官能团有关,其形成机理为炭化过程。极性测试表明炭微球表面存在大量非极性基团,这有利于炭微球在非极性溶液中的吸附。在对碱性和酸性染料的吸附中,多孔炭微球对酸性染料表现出了较高的吸附能力。     

壳聚糖/酵母菌复合炭微球的制备及吸附性能研究

以壳聚糖包裹酵母菌(CWY)为前驱体,在氮气保护条件下,400℃炭化制备出了石榴结构型多孔炭微球。利用扫描电镜、X射线衍射和红外光谱分别对CWY炭微球的形貌和物化结构进行了表征,测试了CWY炭微球的极性,并采用Boehm滴定法对其表面酸性基团进行了分析。结果表明:生成的酵母炭颗粒均匀镶嵌在CWY炭微球内,CWY炭微球在非极性溶液中表现出更好的分散性能,且其表面酸性基团总量为3.281mmol/g。考察了CWY炭微球对强力霉素废水的吸附处理能力,在碱性条件下,CWY炭微球对强力霉素废水(10mg/L)的吸附符合Langmiur模型,50℃时最大吸附量为3.07mg/g。     

淀粉基炭微球的制备及结构分析

以马铃薯淀粉为原料,采用磷酸氢二铵进行稳定化处理,然后通过炭化制得了淀粉基炭微球。采用SEM、TEM、XRD和N2吸附实验对所制得的炭微球的形貌和结构进行了表征。研究表明,实验所制备的炭微球成功地保持了原料淀粉的天然球形形貌,其碳质结构具有典型的无定形结构特点,但在其无序结构周围存在着一些炭微晶。炭微球的BET比表面积为554m2/g,总孔容为0.26cm3/g。同时,通过FT-IR对磷酸氢二铵的稳定化机理进行初步的分析,结果表明,磷酸氢二铵对淀粉的化学脱水反应具有较好的催化作用,有利于淀粉在稳定化、炭化过程中保持原有球形颗粒结构。     

锂离子电池负极材料中间相炭微球的表面镀镍修饰研究

采用化学镀的方法在石墨化中间相炭微球的表面镀覆金属镍,采用扫描电镜对镀覆后的炭微球进行了表面分析,采用X-射线衍射的方法对镀镍炭微球进行了物相分析,将镀覆后的中间相炭微球用于锂离子电池负极材料,并进行了不同倍率的充放电分析及交流阻抗研究。结果表明,在不使用活化剂和敏化剂的情况下,金属镍仍然能够沉积在炭微球的表面;炭微球的大电流放电性能大大提高,在2C放电电流下的放电容量提高了23%,镀镍后交换电流密度增大并且SEI膜电阻减小,炭微球的反应活性大大提高。     

Application of microcapsulation technology to the preparation of carbon foam

Abstract

Microcapsules were prepared by in situ polymerization and microcapsulation. Tetraethyl orthosilicate was used as the core material and phenolic resin was used as the wall material in an emulsion system of polyacrylic and tetraethyl orthosilicate. The obtained microcapsules were slowly heated such that the core material was released by evaporation, leaving hollow-core spheres. The spheres were mixed with a phenolic resin-derived binder and molded to obtain a carbon foam precursor, which was carbonized at 1100 °C under the protection of N₂ gas and graphitized at 2300 °C under the protection of Ar gas. Thus, the carbon foam of hollow closed-shelled microspheres with a graphitic structure was prepared. The properties and structure of this foam were discussed.     

Application of microcapsulation technology to the preparation of carbon foam

Microcapsules were prepared by in situ polymerization and microcapsulation. Tetraethyl orthosilicate was used as the core material and phenolic resin was used as the wall material in an emulsion system of polyacrylic and tetraethyl orthosilicate. The obtained microcapsules were slowly heated such that the core material was released by evaporation, leaving hollow-core spheres. The spheres were mixed with a phenolic resin-derived binder and molded to obtain a carbon foam precursor, which was carbonized at 1100 °C under the protection of N₂ gas and graphitized at 2300 °C under the protection of Ar gas. Thus, the carbon foam of hollow closed-shelled microspheres with a graphitic structure was prepared. The properties and structure of this foam were discussed.     

Adsorption behavior of carbon nanotubes on polystyrene surfaces

Polystyrene (PS) was prepared using two different polymerization methods (dispersion polymerization and seed polymerization) to investigate the steric stabilizer effect during the adsorption process of carbon nanotubes (CNTs) on the surface of PS microspheres. Experiments with different microsphere diameters and difference types of CNTs were conducted to analyze the curvature effect of the spheres on the adsorption mechanism. The results showed that PS microspheres prepared through dispersion polymerization exhibited preferable adsorption behavior compared to PS spheres prepared through seed polymerization, suggesting that poly(N-vinylpyrrolidone) led to improved adsorption interactions between the CNTs and the PS microspheres in the CNTs dispersion. Additionally, the PS diameter and CNT curvature were examined with respect to the adsorption behavior between the PS microspheres and the CNTs. Multiwalled carbon nanotubes (MWCNTs) were found to be well adsorbed on the surface of PS microspheres measuring 2 microm. However, the MWCNTs were adsorbed much less on the surface of submicron-sized PS microspheres, compared with thinwalled carbon nanotubes (TWCNTs). On the other hand, TWCNTs were found to be suitable for adsorption on submicron-sized PS microspheres. These results also indicate that the curvature of the CNTs and the polymer microspheres are important to the CNT adsorption process.     

Characteristics of carbon microspheres and study on its adsorption isotherms

In this paper a great deal of carbon microspheres with high purity, uniform diameter and good features were synthesized by CVD method, while acetylene and toluene were used as carbon sources. The obtained carbon microspheres were almost amorphous. The products were treated by microwave plasma and temperature vacuum heat treatments respectively, then the samples were analyzed and characterized by FESEM, XRD and HRTEM. The results showed that carbon microspheres were well graphitized while their features were undestroyed. Based on their adsorption isotherms of nitrogen, pore structures of carbon spheres were found to be changed greatly after graphitized treatments.     

Preparation and application of novel magnetically separable γ-Fe2O3/activated carbon sphere adsorbent

Magnetic γ-Fe₂O₃/activated carbon microspheres have been synthesized by an activation process of carbon microspheres containing iron oxides, which were prepared by hydrothermal method. The structure and morphology of the magnetic porous carbon microspheres were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), thermogravimetry and differential thermal analysis (TG-DTA) and N₂ adsorption-desorption technique. The results showed that the as-prepared activated carbon spheres were the composite of single-phase γ-Fe₂O₃ and activated carbon material, and the content of carbon was about 3.87%. Using methyl orange as model pollutant, the magnetic porous carbon microspheres showed good adsorption capacities of 44.65 mg/g. The isotherm evaluations revealed that the Langmuir model attained better fits to the experimental equilibrium data than the Freundlich model. These magnetic porous carbon microspheres could potentially be applied in separation processes.     

氧化锌空心球的制备及其气敏性能研究

以新制的碳球为模板在溶液相中制备了氧化锌空心球,并制成气敏元件,进行了气敏性能测试。结果表明,氧化锌空心球气敏元件对乙醇、丙酮和三乙胺有很好的敏感性。尤其是对三乙胺和乙醇分别在175℃和400℃表现出高的灵敏度和快的响应特性。     

Preparation and photocatalytic property of porous CuO hollow microspheres via carbon sphere templates

Porous copper oxide (CuO) hollow microspheres have been successfully fabricated by using carbon spheres as templates. The products were characterized by scanning electron microscopy (SEM), X-ray diffractometry (XRD) and Fourier transform infrared spectroscopy (FTIR). The influences of different experimental parameters on the morphology of CuO structures have been investigated in detail and the possible formation mechanism of porous CuO hollow microspheres has also been proposed. The specific surface area of the hollow spheres with 74.805 m2/g is measured by BET method. Barrett-Joyner-Halenda (BJH) calculations for the pore size distribution, derived from desorption data, reveal that the average pore radius is 8.56 nm, and the total pore volume (r = 1686.1 A, P/P0 = 0.994296) is 0.107257 cc/g. UV-vis absorption spectrum shows quantum size effect of porous CuO hollow microspheres. Furthermore, the porous CuO hollow microspheres exhibit high efficiency for photodegradation of a sample organic dye, Rhodamine B (RhB), under UV light.     

Quasi-static uni-axial compression behaviour of hollow glass microspheres/epoxy based syntactic foams

Hollow glass microspheres/epoxy foams of different densities were prepared by stir casting process in order to investigate their mechanical properties. The effect of hollow spheres content and wall thickness of the microspheres on the mechanical response of these foams is studied extensively through a series of quasi-static uni-axial compression tests performed at a constant strain rate of 0.001 s^?1. It is found that strength of these foams decreases linearly from 105 MPa (for the pure resin) to 25 MPa (for foam reinforced with 60 vol.% hollow microspheres) with increase in hollow spheres content. However, foams prepared using hollow spheres with a higher density possess higher strength than those prepared with a lower one. The energy absorption capacity increases till a critical volume fraction (40 vol.% of the hollow microspheres content) and then decreases. Failure and fracture of these materials occur through shear yielding of the matrix followed by axial splitting beyond a critical volume fraction.