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Color improvment of C 9 hydrocarbon resin by hydrogenation over 2% Pd/γ‐alumina catalyst: Effect of degree of aromatic rings hydrogenation
Author(s) -
SaeMa Nikom,
Praserthdam Piyasan,
Panpranot Joongjai,
Chaemchuen Somboon,
Dokjamp Siraprpha,
Suriye Kongkiat,
Rempel Garry L.
Publication year - 2010
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.32189
Subject(s) - alicyclic compound , chemistry , aromaticity , aromatic hydrocarbon , fourier transform infrared spectroscopy , catalysis , hydrocarbon , nuclear chemistry , organic chemistry , polymer chemistry , molecule , chemical engineering , engineering
Color improvement of commercial C 9 hydrocarbon resin (c‐C 9 HR) and prepared C 9 hydrocarbon resin (p‐C 9 HR) has been investigated under various hydrogenation conditions over 2% Pd/γ‐alumina catalysts. The degrees of aromatic rings hydrogenation (DHs) and molecular structure of resin were determined from nuclear magnetic resonance of 1 H and 13 C ( 1 H‐NMR and 13 C‐NMR) and Fourier transform infrared spectroscopy (FTIR) analyses. The starting c‐C 9 HR presented in yellow color (Gardner color No. 8.4). Under the hydrogenation conditions used (H 2 pressure 70 bar, 250°C, and 8 h), the ethylenic proton in c‐C 9 HR was completely removed, but the aromatic rings content remained unaltered and very little change in resin color was observed (Gardner color No.8.1). On the other hand, the starting p‐C 9 HR contained only unsaturated aromatic proton with Gardner color No.17.1. Under similar conditions, aromatic rings in p‐C 9 HR were converted to alicyclic rings, and its color was reduced to Gardner color No.5.7. By varying the DH of aromatics in p‐C 9 HR, two‐step decolorization was observed in which at lower DH (≤10%) the color decreased sharply from 17.1 to 9.3, while further color reduction to 5.7 was obtained when the DH was increased to 94%. It is suggested that both color body and aromatic rings were the main sources contributing to C 9 HR color. Nevertheless, color stability of the resin during heat treatment was significantly improved by hydrogenation especially at DH ≥ 50%. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010