In order to improve the thermal stability of condensed polynuclear aromatic(COPNA) resin synthesized from vacuum residue, 1,4-benzenedimethanol was added to cure COPNA resin. The curing mechanism was investigated by proton nuclear magnetic resonance spectrometry, solid carbon-13 nuclear magnetic resonance spectrometry and Fourier transform infrared spectroscopy. Microstructures of the uncured and the cured COPNA resins were studied by scanning electron microscopy and X-ray diffractometry. The thermal stability of COPNA resins before and after curing was tested by thermogravimetric analysis. The element composition of the cured COPNA resin heated at different temperatures was analyzed by an element analyzer. The results showed that the uncured COPNA resin reacted with the cross-linking agent during the curing process, and the curing mechanism was confirmed to be the electrophilic substitution reaction. Compared with the uncured COPNA resin, the cured COPNA resin had a smooth surface, well-ordered and streamlined sheet structure with more crystalline solids, better molecular arrangement and orientation. The weight loss process of the uncured and cured COPNA resins was divided into three stages. Carbon residue of the cured COPNA resin was 41.65% at 600 ℃, which was much higher than 25.02% of the uncured COPNA resin, which indicated that the cured COPNA resin had higher thermal stability.
Li ShibinSun QiqianWang YuweiWu MingboZhang Zailong
As a kind of low-cost and readily available industrial byproduct, ethylene tar (ET) was for the first time utilized for the preparation of heat-resistant condensed polynuclear aromatic resin (COPNAR). The basic properties of ET and the resulted COPNAR were characterized by FT-IR, 1H-NMR, TGA and elemental analysis. The test results showed that ET with high aromatic content (>50%) was suitable for the synthesis of COPNAR with superior heat resistance. The average molecular structure of ET was obtained by means of the improved Brown-Ladner method, and the reaction mechanism was considered as an acid-catalyzed positive ion-typed polymerization. Our findings have provided a new route to develop ET into technology-added heat-resistant resins.
As an industrial byproduct of oil refining,furfural extract oil from reduced-pressure route Ⅱ with high aromatic content was used to prepare heat-resistant condensed polynuclear aromatic(COPNA) resin for the first time.The basic properties of furfural extract oil and the resultant COPNA resin were characterized by infrared spectroscopy(FT-IR),nuclear magnetic resonance spectroscopy(1H-NMR),thermogravimetric analysis(TGA) and elemental analysis(EA).The result showed that heat treated furfural extract oil was successfully used for the synthesis of heat-resistant COPNA resin.The average structural parameters of raw materials and prepared resin were calculated by the improved Brown-Ladner method,and the averaged molecular structure of the resin was obtained.The reaction mechanism for the synthesis of COPNA resin was suggested as an acid-catalyzed positive ion type polymerization.
