The Preparation and Characterization of a Novolac Cured Epoxy-Clay Nanocomposites
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0939-O03-33
The Preparation and Characterization of a Novolac Cured Epoxy-Clay Nanocomposites Tsung-Yen Tsai, Shau-Tai Lu, Chih-Hung Li, Chin-Jei Huang, Li-Chun Chen, and Jia-Xiang Liu Dept of Chemistry, Center for Nanotechnology, R&D Center for Membrane Technology, Chung Yuan Christian University, 200, Chung Pei Road, Chung Li City, TAIWAN, 32023, Taiwan
ABSTRACT Intercalated or exfoliated nanocomposites were composed by the novolac cured epoxy and one of three different kinds of layered silicates, such as montmorillonite (PK-802), saponite (Semecton-SA) and nontronite (PK-805). The bi-functional modifiers (PI/BEN or MI/BEN) with different ratio, which contained one of the promoters (2-phenylimidazole, PI and 2methylimidazole, MI) of epoxy and benzalkonium chloride (BEN), were intercalated into the gallery regions of pure clays at the same time and followed by a crosslinking reaction. The properties of novolac cured epoxy/clay nanocomposites were characterized by wild-angle X-ray diffraction (WAXRD), thermal analysis (TGA/DSC), coefficiency of thermal expansion (TMA), mechanical properties (DMA), and transmission electron microscopy (TEM). According to the measurement, these novolac cured epoxy-clay nanocomposites have shown the significant improvement in the thermal, mechanical and barrier properties. INTRODUCTION Nanocomposites, composed of clay and polymer, have been studied extensively for a period of time and it has been shown which many properties are enhanced in the presence of a small amount of clays [1-8]. By employing minimal addition levels (10
Tg () (DMA) 187.7 178.9 188.9 Samples were cooked at 120 under high pressure for 3 hours Durable time when samples were immerged in 288 solder bath.
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The circuit board containing 5 wt% novolac cured epoxy/clay had a coefficient of thermal expansion (CTE) of 54.25 and 45.61 ppm/°C below Tg (α1) in the thickness (Z) direction for MB/PK-802 and MB/PK-805 modified clays respectively. The improvement in the dimensional stability is significant when compared to the counterpart in absence of the clay mineral, which had a CTE of 62.23 ppm/°C below Tg in the Z direction. In addition, the water uptake was decreased by 12.5%~21.8%, i.e., from 0.64 wt% to 0.50 wt% and 0.52 wt% for MB/PK-802 and MB/PK-805 modified clays respectively. The adhesion of nanocomposites was increased from 8 lb/in to 10 lb/in. This result is very desirable especially in electronic applications wherein water absorption is detrimental to dielectric performance. As to the thermal stability, the durable time in 288°C solder bath was significantly increased from 3 minutes to over 10 minutes.
CONCLUSIONS In this paper, we prepared series types of different modified clays in novolac cured epoxy. Clays could not be dispersed well in the resin when they were non-modified or mono modified clays. The larger d-spacing of the modified clays, the better properties have been improved. The copper-clad laminar, which contained modified clays, can pass the strict tests, such as lower water absorption, lower
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