• Applied Chemistry for Engineering
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• v.24 no.4
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• pp.402-406
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• 2013

In this study, a pitch for melt-electrospinning was prepared from naphtha cracking bottom (NCB) oil by the modification with heat treatment. The softening point and property of the modified pitch was influenced by modification conditions such as nitrogen flow rate, heat treatment temperature, and reaction time. Among these, the heat treatment temperature had a very strong influence on the distribution of molecular weight and softening point of the pitch. The C/H mole ratio and average molecular weight increased with increasing the heat treatment temperature due the decomposition and cyclization reaction of surface-functional groups. In addition, the values of benzene insoluble and quinoline insoluble also tends to decrease, and the width of molecular weight distribution seems to get more narrow. The carbon fiber with a diameter of $4.8{\mu}m$ was prepared from a modified pitch at the softening point of $155^{\circ}C$ by melt-electrospinning. It is believed that the melt-electro spinning method is much more convenient to get the thinner fiber than the conventional melt spinning method.

• Korean Journal of Materials Research
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• v.23 no.5
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• pp.276-280
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• 2013

Coal tar is the primary feedstock of premium graphitizable carbon precursor. Coal tars are residues formed as byproducts of thermal treatments of coal. Coal tar pitches were prepared through two different heat treatment schedules and their properties were characterized. One was prepared with argon and oxidation treatment with oxygen; the other was prepared with oxygen treatment at low temperature and then argon treatment at high temperature; both used coal tar to prepare coal tar pitches. To modulate the properties, different heat treatment temperatures ($300{\sim}400^{\circ}C$) were used for the coal tar pitches. The prepared coal tar pitches were investigated to determine several properties, such as softening point, C/H ratio, coke yield, and aromaticity index. The coal tar pitches were subject to considerable changes in chemical composition that arose due to polymerization after heat treatment. Coal tar pitch showed considerable increases in softening point, C/H ratio, coke yields, and aromaticity index compared to those characteristics for coal tar. The contents of gamma resin, which consists of low molecular weight compounds in the pitches and is insoluble in toluene, showed that the degree of polymerization in the pitches was proportional to C/H ratio. Using an oxidizing atmosphere like air to prepare the pitches from coal tar was an effective way to increase the aromaticity index at relatively low temperature.

• International Journal of Highway Engineering
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• v.19 no.2
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• pp.17-24
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• 2017

PURPOSES : This study aims to develop a sealant for use in the installation of Weigh-In-Motion (WIM) sensor for asphalt concrete or cement concrete pavements. METHODS : In order to investigate the properties of various sealants that were mixed with latex and carbon fiber, various test methods were adopted, such as bituminous bond strength test, softening point test, and cone penetration test. To evaluate moisture susceptibility, the BBS test was conducted under moist condition. The bond strength ratio (BSR) was calculated based on tensile strength ratio method. RESULTS : The sealant's properties significantly varied according to the amount of latex or carbon fiber. The usage of latex marginally enhanced the cone penetration test result, notwithstanding reduced asphalt content. This implies that the sealant will be proper cold temperature reason. Moreover, the addition of latex and carbon fiber evidently increased the softening point. This indicates that the tendency of the material to flow at elevated temperatures is encountered during service. With the addition of latex and carbon fiber, the moisture susceptibility measured with BSR improved marginally, while the bond strength under dry condition decreased marginally. Sealant F displays the highest bond strength and BSR under limited test conditions. CONCLUSIONS : According to the proportion of latex and carbon fiber mixed, properties of sealant, such as softening point, cone penetration, and BSR varied marginally. This indicates that the sealant has to be applied considering the environmental condition, to improve service life.

• Journal of Adhesion and Interface
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• v.15 no.4
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• pp.145-150
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• 2014

Dicyclopentadiene (DCPD)-based hydrocarbon resins are widely used as tackifiers in many applications. In particular, hydrogenated DCPD-based hydrocarbon resins are widely used in premium hot-melt-type adhesives such as hot melt adhesives (HMAs) and/or hot melt pressure-sensitive adhesives (HMPSAs), because are water-white in color and possess excellent stability to light and heat. This article discusses the adhesive performance of various hydrogenated DCPD resins when they are used as tackifiers in styrene-block-copolymer (SBC)-based HMPSAs. This article shows the correlation between the characteristics of tackifiers and the adhesive performance of SBC-based HMPSAs. The higher the softening point of the tackifier, the higher is the $T_g$, softening point, and crossover temperature of the PSAs. High aromatic H wt% content reduces the high-temperature resistance of PSAs, as suggested by the decrease in the crossover temperature and softening point of the PSAs.

• Korean Chemical Engineering Research
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• v.43 no.6
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• pp.745-750
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• 2005

Naphtha cracking bottoms(NCB) oil was reformed by varying the heat treatment temperature, treatment time, and nitrogen flow rate in preparation of precursor pitch for isotropic pitch-based carbon fibers and activated carbon fibers. The reformed pitches were investigated in the yield, softening point, elementary analysis, and molecular weight distribution, and then the precursors reformed were melt spun to certify the optimum reforming conditions. The optimum precursor pitch was prepared when the NCB oil was reformed at $380^{\circ}C$, 3 h and 1.25 vvm $N_2$, and it's the softening point was around $240^{\circ}C$. The reforming resulted in product yield of 21 wt％. The C/H mole ratio of the precursor pitch increased from 1.07 to 1.34, the aromaticity increased from 0.85 to 0.88. The insolubles in benzene and quinoline were 30.0 wt％ and 1.5 wt％, respectively. The spinning temperature was about $50^{\circ}C$ higher than the softening point. The molecular weights of the precursor components were distributed from 250 to 1250, and 80％ of them were in the range of 250 to 700.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.331-336
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• 2019

In this study, required properties and optimized procedure conditions for the pitch based soft carbon anode of lithium ion battery was investigated for improving the initial efficiency and rate performance. Each petroleum residue was thermally treated at 360, 370, and $410^{\circ}C$ for 3 hours to synthesis a pitch and the corresponding pitch shows the softening point of 86, 98, and $152^{\circ}C$, respectively. The elemental analysis and thermal characteristics of the pitch were investigated by EA analysis and TGA. It was noted that the low H/C and improved thermal stability were obtained with the high softening point. The obtained pitch was carbonized at $1,200^{\circ}C$ for 1 hour to produce a soft carbon based anode. As a result of investigating the crystal structure by XRD analysis, it was found that the crystallinity of soft carbon increased with increasing the softening point. It was considered that relatively higher boiling components and decreases in the evaporation component resulted the components participation for cyclization during the heat treatment process. The soft carbon based anode with an improved crystallinity shows the enhanced initial efficiency and rate performance. The mechanism of both improvements was also discusssed based on the developed crystal structure of soft carbon based anode materials.

• Journal of the Korean Chemical Society
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• v.11 no.1
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• pp.17-21
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• 1967

For utilization of Bunker-C residual oil produced at KOCO., the auther tested the properties of vacuum fraction and blown asphalt, and as the result of it, (1) Vacuum fraction had so broad range of viscosity and high flash point that could be produced all kind of lublicating oil, but had to be dewaxed for high pour point, (2) Urea dewaxing was suitable to lighter fraction but not to heavier fraction, so, for heavier fraction, solvent dewaxing was needed. (3) Blown asphalt produced from vacuum residue had uniform relation between softening point and penetration in spite of broad change of blowing condition and adding of catalyst.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.8
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• pp.4028-4032
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• 2013

Recycling method for pyrolyzed carbon black from pyrolysis process of waste tires is needed. Carbon black from pyrolysis of waste tires was used to modify and improve the permanent deformation properties of asphalt binder. 0%, 5%, 10%, 15% and 20% of pyrolyzed carbon black was mixed. Couple of laboratory tests, such as softening point, flash point test, rotational viscometer test and dynamic shear rheometer test, were carried out. The use of pyrolyzed carbon black incresed the softening point, rotational viscosity at 135oC, and resistance of permanent deformation.

• Carbon letters
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• v.25
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• pp.78-83
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• 2018

Pyrolyzed fuel oil (PFO) and coal tar was blended in the feedstock to produce pitch via thermal reaction. The blended feedstock and produced pitch were characterized to investigate the effect of the blending ratio. In the feedstock analysis, coal tar exhibited a distinct distribution in its boiling point related to the number of aromatic rings and showed higher Conradson carbon residue and aromaticity values of 26.6% and 0.67%, respectively, compared with PFO. The pitch yield changed with the blending ratio, while the softening point of the produced pitch was determined by the PFO ratio in the blends. On the other hand, the carbon yield increased with increasing coal tar ratio in the blends. This phenomenon indicated that the formation of aliphatic bridges in PFO may occur during the thermal reaction, resulting in an increased softening point. In addition, it was confirmed that the molecular weight distribution of the produced pitch was associated with the predominant feedstock in the blend.

• Elastomers and Composites
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• v.49 no.3
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• pp.245-252
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• 2014

FT-IR measurement and the physical properties of polyurethane adhesive prepared from the polyol, isocyanate, 2-HEMA and other acrylate monomers were examined. The softening point, viscosity, adhesion strength and mechanical properties of the PU adhesives were reviewed by Ring and Ball method, Brookfield viscometer and universal test machine, respectively. Results revealed that increment of both PPG amount and butyl acrylate content decreased softening point, adhesion strength, tensile strength and 100% modulus. However as 2-HEMA and MDI content increased the mechanical properties including tensile strength, 100% modulus increased, and also the viscosity and NCO content increased.