Studying water uptake effects in resins based on cyanate ester/bismaleimide blends

The analysis of cured resin blends comprising cyanate ester and bismaleimid e (BMI) to determine the chemical effects of long-term exposure to water is reported. The cured resin blends underwent accelerated water uptake by imm ersion in water at temperatures of up to 70 degrees C, for a period of 18 m onths. Blistering and severe micro-cracking occurred, leading to severe wea kening of the worst affected blends. Photomicrographs confirmed that the wo rst affected resins, containing high BMI contents, displayed two-phase morp hologies. Thermo gravimetric analysis and dynamic mechanical thermal analys is were performed on neat resin samples before and after immersion. Spectro scopy (near infrared Raman, diffuse reflectance and mid-infrared) was perfo rmed on powdered resin samples to determine the nature of the chemical chan ges occurring during the degradation. The elemental composition of the samp les was also determined before and after conditioning. Crown copyright (C) 2000 Published by Elsevier Science Ltd. All rights reserved.