Petroleum Engineering. In: International Conference on Coal Science and Technology. 1999;44:764–74. In the range of higher frequencies, values of loss modulus were higher than of storage modulus. The coal-tar pitch and compound containing 25% of resin by mass showed highest ability to dissipate energy at highest frequencies, i.e. The frequency relationships of phase angle and loss tangent (tg δ = G″ = G′) (Figs. Thermal factor played a decisive role in all examinations. For example, thermal treatment in an inert atmosphere and air-blowing are the processes generally used to reduce the emission of volatiles during pitch processing and also to increase pitch C value, without altering most of the fundamental characteristics of the pitch (e.g., wetting capacity, fluidity, etc.). Fig 1 Schematics of the production of coal-tar pitch and anthracene oil-based pitch. J Therm Anal Calorim. [4] Another experiment was started by a colleague of Nobel Prize winner Ernest Walton in the physics department of Trinity College in Ireland in 1944. T� �7�h�[FGGG�`��c0i IF W�$ d#8 epRPfH!�5i30���b@, ��:� C1�$��{�>0� E�2˱W1�a�˨ǐ=�=�j� Coal-tar pitch modified with phenol-formaldehyde resin can be used as the precursor for the production of porous materials. 1999;79:1583–9. Petroleum. 2012;109:767–72. It implied the occurrence of chemical reactions leading to formation of components of probably substantial molecular masses, as a result of crosslinking, among others. Determined results for that compound were compared with characteristics of unmodified coal-tar pitch. Acute, or short-term, exposure to coal tar pitch has been associated with several health effects. The ability of pitch to flow, albeit slowly, keeps it in constant uniform contact with the optical surface. [19]. Therefore, attempts to modify the coal bitumen to decrease its cancerogenicity and to improve technological and quality properties have been done for many years. Environmental concerns related to coal tar pitch. 0000004856 00000 n 2012;109:789–95. Naturally occurring asphalt/bitumen, a type of pitch, is a viscoelastic polymer. >> High Viscosity Blended Bitumen Pitch,Coal Tar Pitch , Find Complete Details about High Viscosity Blended Bitumen Pitch,Coal Tar Pitch,High Viscosity Blended Bitumen Pitch from Bitumen Supplier or Manufacturer-Waterproof Materials Co., Ltd First, the theological properties, viscosity in particular, are a decisive factor for the development of anisotropy during the formation of mesophase. Polimery. Some products made from plant resin are also known as rosin. Addition of phenol-formaldehyde resin increased the fraction of viscoelastic characteristics of bitumen. It was decided to measure the changes in viscoelastic properties versus frequency of coal-tar pitch and pitch–phenol-formaldehyde resin compounds (without crosslinking) at as low as possible temperature (109 °C) which reduces to minimum the possibility of crosslinking reaction during measurement. KFR�s�����Q�:@�Zh�,���4Q��9ý��[���J�G3at:��1y�G�\��n3ٖ��g��(x�!m����h�,���U23d�襲D��7��r.�9���p�c.�^ �6b�_f��jH��b�� ��'�e[��;�x��d�c �k��8Η\�w��Pm!U8.�13m�Di��dD�@j!+�1�B�@�Eb�+^,��p The result is pitch which is able to generate carbons with a lower porosity, higher density and pre-graphitic order. coals subjected to high-temperature carbonizing process in order to obtain porous materials, it is essential to assure high flowability (low viscosity) at carbonizing conditions as well as appropriate mechanical strength. It is also very poorly soluble in water. The group composition is primarily responsible for the technological properties of pitch such as softening temperature, dynamic viscosity, fluidity at a specific temperature, coking property, and the yield of coke residue. Coal tar pitch is the tar distillation residue produced during coking operations (NIOSH 1977). Creosote oil Dead oil Call fire department. [14,15,16,17] Blends of this polymer with other substance can be used for the preparation of carbon-mineral materials, for example. An important qualitative characteristic of pitch is its group composition evaluated based on solubility in different organic solvents namely (i) the concentrations of substances soluble in petroleum ether (gamma fraction), soluble in toluene but insoluble in petroleum ether (beta fraction), and insoluble in toluene (alpha fraction). Therefore, assessment of changes in rheological properties versus temperature was carried out for the pitch with 25% of phenol-formaldehyde resin by mass, crosslinked for 2.0 h. Such compound had high softening temperature while still being the substance susceptible to melting, which characteristics enabled the preparation of suitable samples for tests. 1996;75:1543–8. Journal of Thermal Analysis and Calorimetry Addition of phenol-formaldehyde resin to the pitch caused changes in the course of viscosity versus temperature dependence. Pitch may also be used to waterproof wooden containers and in the making of torches. For the experiment, pitch was put in a glass funnel and allowed to slowly drip out. Together with both increase in resin addition and extension of crosslinking time, changes in evaluated properties became more intense. Such possibilities are provided by modification of coal bitumen with polymers [1,2,3], among others. 5, 6). Hard pitch is used as a binder for foundry cores. 2), it was found that the compounds which did not undergo crosslinking demonstrated higher viscosity in comparison with the coal-tar pitch in the whole frequency range at temperature 109 °C. The possibility of further crosslinking of the resin at measurement conditions was also minimized in the case of that compound.