Influence of coupling agents on properties of aluminum borate whiskers modified BMI resin

The mechanical behavior of aluminum borate whiskers modified BMI resin was investigated. Surface treatment of whiskers by several coupling agents such as silane and borate esters synthesized by our lab were used to improve the interface properties between whiskers and resin. The results showed that borate esters coupling agents treated whiskers made the composites have better surface property than silane treated whiskers and untreated whiskers. Addition of 3% borate ester (BE4) treated whiskers in an BMI resin increased the flexural strength of the composites obviously, and the impact strength of the composites increased, too. The heat distortion temperature and the flexural modulus of the composites increased with the increase of the whisker content. SEM showed that the borate esters coupling agent made the composites have better interface properties. Mixing 3 parts and 100 parts BMI resin, the test piece had impact strength of 12.8 kJ/m², flexural strength of 146.4 MPa, flexural modulus of 3.8 GPa, vs. 12.6, 118.0, 3.5 respectively, without aluminum borate whiskers.