TY - JOUR
T1 - Angle-Resolved HAXPES Investigation on the Chemical Origin of Adhesion between Natural Rubber and Brass
AU - Ozawa, Kenichi
AU - Kakubo, Takashi
AU - Amino, Naoya
AU - Mase, Kazuhiko
AU - Ikenaga, Eiji
AU - Nakamura, Tetsuya
N1 - Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/9/26
Y1 - 2017/9/26
N2 - Bulk sensitivity of hard X-ray photoelectron spectroscopy (HAXPES) makes this technique suitable for chemical state analysis of bulk and deeply buried interfaces of solid materials. HAXPES is employed in the present study to examine the chemical state of adhesive interfaces between natural rubber and copper-zinc alloy, i.e., brass, while maintaining the adhesion structure in order to understand the chemical mechanism of rubber-to-brass adhesion. Angle-resolved measurements allow to distinguish between chemical species in rubber and those at the adhesive interface. We specially focus on sulfur-containing species because metal sulfides at the interface have been suggested to be crucial for adhesion. Line-shape analysis of S 1s spectra reveals that the interface that exhibits a strong adhesive property is mainly composed of copper sulfides with a predominant amount of CuS. This type of the interfacial chemical state is obtained when a rubber-bonded brass sample is subjected to vulcanization at 170 °C for 10 min. However, prolonged vulcanization leads to a partial dissolution of CuS as well as accumulation of Zn species in the form of ZnO/Zn(OH)2 and ZnS, and as a result, adhesion strength is lowered. The present study paves the way for accurate and detailed discussion on the chemical state of deeply buried interfaces through bulk sensitive in-situ measurements.
AB - Bulk sensitivity of hard X-ray photoelectron spectroscopy (HAXPES) makes this technique suitable for chemical state analysis of bulk and deeply buried interfaces of solid materials. HAXPES is employed in the present study to examine the chemical state of adhesive interfaces between natural rubber and copper-zinc alloy, i.e., brass, while maintaining the adhesion structure in order to understand the chemical mechanism of rubber-to-brass adhesion. Angle-resolved measurements allow to distinguish between chemical species in rubber and those at the adhesive interface. We specially focus on sulfur-containing species because metal sulfides at the interface have been suggested to be crucial for adhesion. Line-shape analysis of S 1s spectra reveals that the interface that exhibits a strong adhesive property is mainly composed of copper sulfides with a predominant amount of CuS. This type of the interfacial chemical state is obtained when a rubber-bonded brass sample is subjected to vulcanization at 170 °C for 10 min. However, prolonged vulcanization leads to a partial dissolution of CuS as well as accumulation of Zn species in the form of ZnO/Zn(OH)2 and ZnS, and as a result, adhesion strength is lowered. The present study paves the way for accurate and detailed discussion on the chemical state of deeply buried interfaces through bulk sensitive in-situ measurements.
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U2 - 10.1021/acs.langmuir.7b01842
DO - 10.1021/acs.langmuir.7b01842
M3 - Article
C2 - 28857567
AN - SCOPUS:85029938073
SN - 0743-7463
VL - 33
SP - 9582
EP - 9589
JO - Langmuir
JF - Langmuir
IS - 38
ER -