The Experts below are selected from a list of 11622 Experts worldwide ranked by ideXlab platform
A Linaressolano - One of the best experts on this subject based on the ideXlab platform.
-
stabilisation of low Softening Point petroleum pitch fibres by iodine treatment
Fuel Processing Technology, 2007Co-Authors: Eduardo Vilaplanaortego, Diego Cazorlaamoros, Juan Alcanizmonge, A LinaressolanoAbstract:A method using iodine has been developed for the stabilisation of low Softening Point (SP) pitch fibres that avoids air stabilisation in the production of carbon fibres (CF). The interaction between iodine and petroleum pitches has been studied by following the changes in the hydrogen content, aromatic or aliphatic, during the heat treatment of iodine-treated pitch fibres. Two low SP petroleum pitches were used and the iodine-treated pitch fibres were analysed by TGA, DSC, DRIFT, XPS and SEM. The results confirm that using this novel method pitches with low SP can be used to prepare CF with two advantages, compared with conventional methods. The stabilisation time is considerably reduced and treatments to increase the SP, usually required when low SP pitches are used to prepare CF, can be avoided.
-
structural characterization of n containing activated carbon fibers prepared from a low Softening Point petroleum pitch and a melamine resin
Carbon, 2002Co-Authors: E Raymundopinero, A Linaressolano, D Cazorlaamoros, Ute Wild, Robert SchloglAbstract:The incorporation of heteroatoms like N in activated carbons is of interest to modify the surface chemistry of the materials and, then, to improve their behavior as catalyst or catalyst support. In this work, N-containing activated carbon fibers have been prepared using a petroleum pitch with a low Softening Point and an N-containing resin. The novelty of the preparation method is that it involves the steps used in the synthesis of activated carbon fibers, i.e. spinning, stabilization, carbonization and activation. The materials have been characterized with techniques such as XPS and UPS, which allows us to follow the changes in both the chemical state of N species and the valence band structure of the carbon samples during the preparation steps.
-
preparation of general purpose carbon fibers from coal tar pitches with low Softening Point
Carbon, 1997Co-Authors: J Alcanizmonge, Diego Cazorlaamoros, A Linaressolano, Asao Oya, A Sakamoto, K HosmAbstract:This paper describes the different procedures applied for the preparation of general purpose carbon fibers from four coal tar pitches. The four raw materials have a low Softening Point (of about 373 K) for this application and, hence, must be subjected to a treatment before spinning to increase this temperature. The treatments applied are the following: (i) heating in N2, (ii) heating in air, (iii) consecutive heating in N2 and air, and (iv) blending of the coal tar pitch with a petroleum one and further treatment in air. The changes in chemical composition, Softening Point and yield of the treatments used have been followed by different techniques. Only treatments (iii) and (iv) produce materials with an adequate viscosity for spinning and a sufficiently high Softening Point to be transformed in carbon fibers. The carbon fibers obtained have similar mechanical properties to those prepared in a previous work from a suitable petroleum pitch with the same experimental system. However, the mechanical properties of these fibers are inferior to those of a commercial carbon fiber, the differences being due to the lower diameter of the commercial fibers.
Xingrong Zeng - One of the best experts on this subject based on the ideXlab platform.
-
two step synthesis and characterization of urea isobutyraldehyde formaldehyde resins
Progress in Organic Coatings, 2009Co-Authors: Yi-fu Zhang, Xingrong ZengAbstract:Abstract Urea–isobutyraldehyde–formaldehyde (UIF) resins were synthesized from urea, isobutyraldehyde and formaldehyde using sulfuric acid as catalyst by two-step method. The effect of molar ratio of isobutyraldehyde to formaldehyde ( n (I)/ n (F)), molar ratio of aldehyde to urea ( n (A)/ n (U)), catalyst concentration and reaction time on the yield, hydroxyl value and Softening Point of UIF resins were investigated. The UIF resins were characterized by Fourier transform infrared spectroscopy (FT-IR), 1 H-nuclear magnetic resonance ( 1 H NMR), gel permeation chromatography (GPC) and thermogravimetric (TG). The results showed that the yield, hydroxyl value and Softening Point of the UIF resin were 76.5%, 90 °C and 32 mgKOH/g, respectively, when the molar ratio of urea to isobutyraldehyde to formaldehyde ( n (U)/ n (I)/ n (F)) was 1.0/3.6/2.4, catalyst concentration was 6.0%, and reaction time in the second step reaction was 3.0 h. FT-IR and 1 H NMR results showed that α-H in isobutyraldehyde participated in the synthesis reaction of UIF resins, and the reaction was Mannich reaction. The amount of aldehyde groups in UIF resins increased with the increase of the amount of isobutyraldehyde. GPC results showed that the UIF resins had narrow molecular weight distribution and TG results indicated that the UIF resin had excellent heat resistance.
-
synthesis and structural characterization of urea isobutyraldehyde formaldehyde resins
Journal of Coatings Technology and Research, 2009Co-Authors: Yi-fu Zhang, Xingrong Zeng, Bi-ye RenAbstract:Urea-isobutyraldehyde-formaldehyde (UIF) resin was synthesized from urea, isobutyraldehyde, and formaldehyde using sulfuric acid as a catalyst by one pot method. The effects of molar ratios of isobutyraldehyde to formaldehyde (n(I)/n(F)) and aldehyde to urea (n(A)/n(U)) on the yield, hydroxyl value (vs KOH) and Softening Point of the resin were investigated. The structure of the resin was characterized by FT-IR, 1H-NMR and 13C-NMR. The results show that when the molar ratio of urea to isobutyraldehyde to formaldehyde (n(U)/n(I)/n(F)) is 1.0/3.0/3.0, the yield UIF resin is 67.1%, and the Softening Point and hydroxyl value are 88 °C and 37 mg/g, respectively. The FT-IR, 1H-NMR and 13C-NMR results show that the lactam is formed by aminomethylation from urea, isobutyraldehyde, and formaldehyde.
Jie Qi - One of the best experts on this subject based on the ideXlab platform.
-
two step chemical conversion of coal tar pitch to isotropic spinnable pitch
Fuel Processing Technology, 2012Co-Authors: Baojun Yu, Jiaming Zheng, Chengyang Wang, Mingming Chen, Jie QiAbstract:Abstract The traditional techniques for preparing spinnable pitch from coal tar pitch are air blowing or thermal treatment. A new method to produce isotropic spinnable pitch has been developed. In this method, a commercial almost free of quinoline insoluble (almost QI-free) coal tar pitch was firstly air blown in the temperature range of 280 to 320 °C. Air blowing increases the Softening Point of the pitch without destroying its spinnability. Next, a thermal treatment between 350 and 380 °C was applied and this increased the Softening Point to 280 °C. The effects of processing parameters such as treatment time and temperature for air blowing and thermal treatment on the characteristics of the spinnable pitch were studied. The spinnable pitch obtained by the two-step technique exhibited a high Softening Point (280 °C), a high coking value (82%). The green fibers spun from the pitch, showed uniform diameters (19 ± 1 μm) with smooth and homogeneous surfaces. The green fibers were then stabilized at 320 °C for 1 h and further carbonized at 1000 °C for 1 h in nitrogen. The obtained carbon fibers also had smooth surfaces and homogeneous diameters (17 ± 1 μm).
Yi-fu Zhang - One of the best experts on this subject based on the ideXlab platform.
-
two step synthesis and characterization of urea isobutyraldehyde formaldehyde resins
Progress in Organic Coatings, 2009Co-Authors: Yi-fu Zhang, Xingrong ZengAbstract:Abstract Urea–isobutyraldehyde–formaldehyde (UIF) resins were synthesized from urea, isobutyraldehyde and formaldehyde using sulfuric acid as catalyst by two-step method. The effect of molar ratio of isobutyraldehyde to formaldehyde ( n (I)/ n (F)), molar ratio of aldehyde to urea ( n (A)/ n (U)), catalyst concentration and reaction time on the yield, hydroxyl value and Softening Point of UIF resins were investigated. The UIF resins were characterized by Fourier transform infrared spectroscopy (FT-IR), 1 H-nuclear magnetic resonance ( 1 H NMR), gel permeation chromatography (GPC) and thermogravimetric (TG). The results showed that the yield, hydroxyl value and Softening Point of the UIF resin were 76.5%, 90 °C and 32 mgKOH/g, respectively, when the molar ratio of urea to isobutyraldehyde to formaldehyde ( n (U)/ n (I)/ n (F)) was 1.0/3.6/2.4, catalyst concentration was 6.0%, and reaction time in the second step reaction was 3.0 h. FT-IR and 1 H NMR results showed that α-H in isobutyraldehyde participated in the synthesis reaction of UIF resins, and the reaction was Mannich reaction. The amount of aldehyde groups in UIF resins increased with the increase of the amount of isobutyraldehyde. GPC results showed that the UIF resins had narrow molecular weight distribution and TG results indicated that the UIF resin had excellent heat resistance.
-
synthesis and structural characterization of urea isobutyraldehyde formaldehyde resins
Journal of Coatings Technology and Research, 2009Co-Authors: Yi-fu Zhang, Xingrong Zeng, Bi-ye RenAbstract:Urea-isobutyraldehyde-formaldehyde (UIF) resin was synthesized from urea, isobutyraldehyde, and formaldehyde using sulfuric acid as a catalyst by one pot method. The effects of molar ratios of isobutyraldehyde to formaldehyde (n(I)/n(F)) and aldehyde to urea (n(A)/n(U)) on the yield, hydroxyl value (vs KOH) and Softening Point of the resin were investigated. The structure of the resin was characterized by FT-IR, 1H-NMR and 13C-NMR. The results show that when the molar ratio of urea to isobutyraldehyde to formaldehyde (n(U)/n(I)/n(F)) is 1.0/3.0/3.0, the yield UIF resin is 67.1%, and the Softening Point and hydroxyl value are 88 °C and 37 mg/g, respectively. The FT-IR, 1H-NMR and 13C-NMR results show that the lactam is formed by aminomethylation from urea, isobutyraldehyde, and formaldehyde.
Baojun Yu - One of the best experts on this subject based on the ideXlab platform.
-
two step chemical conversion of coal tar pitch to isotropic spinnable pitch
Fuel Processing Technology, 2012Co-Authors: Baojun Yu, Jiaming Zheng, Chengyang Wang, Mingming Chen, Jie QiAbstract:Abstract The traditional techniques for preparing spinnable pitch from coal tar pitch are air blowing or thermal treatment. A new method to produce isotropic spinnable pitch has been developed. In this method, a commercial almost free of quinoline insoluble (almost QI-free) coal tar pitch was firstly air blown in the temperature range of 280 to 320 °C. Air blowing increases the Softening Point of the pitch without destroying its spinnability. Next, a thermal treatment between 350 and 380 °C was applied and this increased the Softening Point to 280 °C. The effects of processing parameters such as treatment time and temperature for air blowing and thermal treatment on the characteristics of the spinnable pitch were studied. The spinnable pitch obtained by the two-step technique exhibited a high Softening Point (280 °C), a high coking value (82%). The green fibers spun from the pitch, showed uniform diameters (19 ± 1 μm) with smooth and homogeneous surfaces. The green fibers were then stabilized at 320 °C for 1 h and further carbonized at 1000 °C for 1 h in nitrogen. The obtained carbon fibers also had smooth surfaces and homogeneous diameters (17 ± 1 μm).
