Zhang Lei, Liu Chunjiang, Jia Yang, Mu Yidan, Yan Yao, Huang Pengcheng
College of Geology and Environment, Xi'an University of Science and Technology, Xi'an 710054, China.
Key Laboratory of Coal Resources Exploration and Comprehensive Utilization, Ministry of Natural Resources, Xi'an 710021, China.
Polymers (Basel). 2024 Jan 4;16(1):161. doi: 10.3390/polym16010161.
In order to achieve the high-value utilization of heavy tar for the production of enhanced-performance graphite foam carbon, the carbon mesophase was ready from the heavy component of low-temperature coal tar, and the coal tar was modified by styrene-butadiene-styrene (SBS), polyethylene (PE) and ethylene-vinyl-acetate (EVA) copolymers. The order degree of the carbonite mesophase was analyzed using a polarizing microscope test, Fourier transform infrared spectroscopy and X-ray diffraction to screen out the most suitable copolymer type and addition amount. Furthermore, the mechanism of modification by this copolymer was analyzed. The results showed that adding SBS, PE and EVA to coal tar would affect the order of carbonaceous mesophase; however, at an addition rate of 10.0 wt.%, the linear-structure SBS copolymer with a styrene/butadiene ratio (S/B) of 30/70 exhibited the optimal degree of ordering in the carbonaceous mesophase. Its foam carbon prepared by polymer modification is the only one that forms a graphitized structure, with d of 0.3430 nm, and the maximum values of Lc and La are 3.54 nm and 2.22 nm, respectively. This is because, under elevated pressure and high-temperature conditions, SBS underwent chain scission, releasing a more significant number of methyl and other free radicals that interacted with the coal tar constituents. As a result, it reduced the affinity density of heavy coal tar molecules, enhanced fluidity, promoted the stacking of condensed aromatic hydrocarbons and increased the content of soluble carbonaceous mesophase, ultimately leading to a more favorable alignment of the carbonaceous mesophase.
为实现重质焦油的高值利用以生产高性能石墨泡沫碳，从低温煤焦油的重组分制备了碳中间相，并采用苯乙烯-丁二烯-苯乙烯（SBS）、聚乙烯（PE）和乙烯-醋酸乙烯酯（EVA）共聚物对煤焦油进行改性。利用偏光显微镜测试、傅里叶变换红外光谱和X射线衍射分析了碳酸盐中间相的有序度，以筛选出最合适的共聚物类型和添加量。此外，还分析了该共聚物的改性机理。结果表明，向煤焦油中添加SBS、PE和EVA会影响含碳中间相的有序度；然而，在添加量为10.0 wt.%时，苯乙烯/丁二烯比（S/B）为30/70的线性结构SBS共聚物在含碳中间相中表现出最佳的有序度。其通过聚合物改性制备的泡沫碳是唯一形成石墨化结构的，d为0.3430 nm，Lc和La的最大值分别为3.54 nm和2.22 nm。这是因为在高压和高温条件下，SBS发生链断裂，释放出更多的甲基等自由基，这些自由基与煤焦油成分相互作用。结果，它降低了重质煤焦油分子的亲和密度，增强了流动性，促进了稠环芳烃的堆积，增加了可溶性含碳中间相的含量，最终导致含碳中间相更有利的排列。
