In this article, a phosphorus containing bismaleimide (V) based on 2-(6-oxido-6H-dibenz kc,el k1,2l6-yl)-1,4-dihydroxy phenylene (I) was synthesized and copolymerized with 4,4 0 -bismaleimidodiphenylmethane (BMDM) in various weight ratio (0–33 phr). DSC scans show that the introduction of V into BMDM has increased the processing window for the resulted copoly(bismaleimide). DMA scans show these cured BMIs exhibit good modulus ( , 2 GPa) up to 4008C. There is no tangent peak for these cured BMIs implying that there is no relaxation below 4008C. TMA scans show introduction of V into BMDM increase the coefficient of thermal expansion (CTE). However, CTE of these cured BMIs are less than 50 ppm, which is much less than common epoxy. There is no second transition during TMA heating scans up to 4408C, so Tgs of these cured BMIs are higher than 4408C, which is consistent with the DMA measurement. TGA heating scans also indicate that they have high thermal stability and their char yields increase with the content of V. Char yields at 8008C shift from 48 to 63 in nitrogen and from 0 to 18 in air when 25 phr of V was introduced into BMDM. TGA isothermal experiments show that these cured BMIs are thermally more stable in air than in nitrogen below 4508C. Char yields also increase with the content of V.
Посилання на статтю:
Synthesis and properties of phosphorus containing copoly(bismaleimide) / Chun Shan Wang, Ching Hsuan Lin // Polymer. – 1999. – N 40. – P. 5665–5673.