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Indexed by:期刊论文

Date of Publication:2013-08-23

Journal:POLYMER

Included Journals:SCIE、EI、Scopus

Volume:54

Issue:19

Page Number:5182-5187

ISSN No.:0032-3861

Key Words:Cycloaliphatic epoxide; Phosphorus; Reworkable

Abstract:The motivation of the present work is to design and synthesize reworkable epoxy resin for electronic packaging which are required to be sufficiently stable before 200 degrees C and can rapidly decompose in the temperature range of 200-300 degrees C. For this purpose, a new trifunctional cycloaliphatic epoxide (Epo-A) with a phosphite center linked by three epoxycyclohexyl groups was prepared. The chemical structure was confirmed by FTIR, H-1 NMR and P-31 NMR spectra. Compared to the phosphate-type analog (Epo-B) and commercial epoxide ERL-4221, Epo-A exhibits the apparently higher curing reactivity. The shearing strength of the cured Epo-A at room temperature is 5.67 MPa, much superior to that of ERL-4221 (3.29 MPa). More importantly, the cured Epo-A can maintain the high shearing strength up to 210 degrees C. Upon further increasing temperature, the network rapidly decomposes, and the strength almost completely losses at around 255 degrees C, just lying in the desirable temperature range for reworking operation. As a result, the dismantlement of the integrated circuit or the replacement of the faulty chip can be realized without damaging the circuit board. In addition, the incorporation of phosphorus in the network results in a significantly increased limiting oxygen index (LOI) from 18.2 (ERL-4221) to 23.2 (Epo-A). The mechanism for the degradation behavior was studied by isothermal and temperature-variable FT-IR spectra in detail. (C) 2013 Elsevier Ltd. All rights reserved.