Synthesis of silicon-containing cycloaliphatic diepoxide from biomass-based α-terpineol and the decrosslinking behavior of cured network

Publication date: 16 June 2017
Source:Polymer, Volume 119
Author(s): Linni Zhao, Zhonggang Wang
The intractable after-treatment problem of thermosetting epoxy resins due to the insolubility and infusibility brings about an ever-increasing pressure on environment. In this work, new degradable silicon-containing cycloaliphatic diepoxide (Epo-Si) was designed and synthesized using biomass-based 2-(4-methylcyclohex-3-enyl)propan-2-ol (α-terpineol) as a major material. After curing with anhydride, large amounts of heat-labile tertiary carbon ester and tertiary C-O ether linkages in the network made the crosslinked Epo-Si degrade at a lower temperature of 269 °C. Moreover, its degradation temperatures could be readily tuned through co-curing with the commercial diepoxide ERL-4221. At room temperature, the shearing strength of the cured Epo-Si is 6.74 MPa, superior to that of ERL-4221 (5.24 MPa), exhibiting excellent adhesion property. More importantly, the cured Epo-Si maintains the high shearing strength up to 240 °C, but when further increasing temperature, the strength rapidly dropped and almost completely lost at around 285 °C. Therefore, if integrated circuits have been encapsulated with Epo-Si, their dismantlement or repair at a suitably lower temperature could be realized without damaging the PCB board. The thermal decrosslinking mechanism of the cured products were investigated by means of isothermal and temperature-programmed thermogravimetric and FTIR spectra in detail.

Graphical abstract

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