| The BMI/DDM/EP polymer(BDME) was synthesized by using bismaleimide, diaminodiphenylmethane and epoxy in this article. The epoxy adhesive modified by bismaleimide of BDME/EP, BDME/EP/UP, BDMQ/EP/UP and BDME/EC were prepared by utilizing BDME with E-51 and flexible epoxy MSQ which were added in the unsaturated polyester resin and CTBN/E-51(EC) polymer. The effect of the content of BDME, the using of flexible epoxy MSQ, the component and content of EC etal factors to the gelation characteristic, shear strength and rupture elongate quotiety, thermal endurance, curing techniques and kinetics of curing reaction, toughening mechanism and application in the flexible printed circuit board of modified epoxy adhesive were studied systematically by gelation apparatus, DSC, TG, TEM, electronic pulled apparatus and the test of weld temperature resistance.It was found that the synthesized polymer of BDME can dissolve the low boiling point impregnant system which could settle the problem both the diffluence of BMI and the consistence of BMI and EP. The thermal endurance of modified adhesive is enhanced after adding BMI and the toughness of modified adhesive is some extent improved by the method of using flexible epoxy MSQ and adding the unsaturated polyester resin. Their shear strength are 30.38MPa and 32.88MPa. However, the toughness and bonding strength of modified adhesive are effectively improved by modifying with EC polymer. when the ratio of EC which has 15% CTBN and BDME is 1/2, the modified epoxy adhesive has a good properties. Its shear strength and rupture elongate quotiety is 50.07MPa and 3.95%, peer strength is 1.16kgf/cm, passed the test of 320℃boiling stannum. This adhesive has some industry applied value, especially the thermal endurance has exceeded the request of presently adhesive used in flexible printed circuit board. The toughening effect and toughening mechanism of epoxy adhesive toughened by CTBN were discussed basing SEM photoes of the curied adhesive, the toughening mechanism is consistent with the mechanism which was brought forward by Pearson and Huang. |
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