Influence of thermal treatment on the glass transition temperature of thermosetting epoxy laminate

• Published in: Polymer testing Vol. 28; no. 4; pp. 428 - 436
• Main Authors: Polanský, R., Mentlík, V., Prosr, P., Sušír, J.
• Format: Journal Article
• Language: English
• Published: Kindlington Elsevier Ltd 01.06.2009; Elsevier
• Subjects: Activation energy; Application fields; Applied sciences; Arrhenius plot; Composite; Dynamic mechanical analysis; Electronics; Epoxy resin; Exact sciences and technology; Microelectronic fabrication (materials and surfaces technology); Polymer industry, paints, wood; Printed circuit board; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Technology of polymers; Epoxy resin; Printed circuit board; Composite; Dynamic mechanical analysis; Activation energy; Arrhenius plot; Heat treatment; Laminate; Thermal ageing; Fiber reinforced material; Processing time; Experimental study; Mineral fiber; Property processing relationship; Glass transition temperature; Composite material; Structure processing relationship; Morphology; Electronic packaging; Glass fiber; Application; Delamination
• ISSN: 0142-9418; 1873-2348
• DOI: 10.1016/j.polymertesting.2009.03.004

The influence of accelerated thermal treatment of thermosetting epoxy laminate on its glass transition temperature was studied. Lamplex ® FR-4 glass fibre-reinforced epoxy laminate (used for printed circuit board manufacturing) was used in these experiments. The composite was exposed to thermal treatments at temperatures ranging from 170 °C to 200 °C for times ranging from 10 to 480 h. The glass transition temperature ( T g) was analysed via dynamic mechanical analysis (DMA). It has been proven that the glass transition temperature rapidly decreases in reaction to thermal stress. The obtained T g data were used for Arrhenius plots for different critical temperatures ( T g-crit. = 105–120 °C). From their slopes (− E a/ R), the activation energy of the thermal degradation process was calculated as 75.5 kJ/mol. In addition to this main relaxation mechanism, DMA also recorded one smaller relaxation process in the most aged samples. Microscopic analysis of the sample structure showed the presence of pronounced small regions of degradation both on the surface and in the inner structure, which are probably the causes of microscopic delamination and the smaller relaxation process.