| Epoxy resin curing agent maleopimaric acid anhydride(MPA) was prepared from renewable resource rosin with dienophile maleic anhydride by Diels-Alder reaction. The curing reaction of epoxy resin 128/MPA was discussed, and the curing performances of epoxy resin 128/MPA, mechanical property and heat-resistant quality included, were analyzed. Then, maleopimaric acid anhydride was used as material to react with three kinds of polyamines (including diethylenetriamine, triethylenetetramine and tetraethylenepentamine) by amidation to prepare three kinds of epoxy resin polyamide curing agents—MPAPA, and the performances of the cured products of epoxy resin 128/MPAPA polyamide were analyzed; Took one of the polyamides that owned the superior performance as example for kinetic analysis, we got the kinetic equation, which can provide theoretical guidance for the application of MPAPA; At last, the MPAPA that owned the superior performance prepared in this paper was used to apply in conductive adhesive as curing agent as well. The influences conductive filler and additives to the conductive properties were discussed.First, epoxy resin curing agent MPA was prepared by rosin by Diels-Alder reaction with maleic anhydride in the paper. MPA was characterized by FT-IR, 1H-NMR and acid value, the cured performances of mechanical property and heat-resistant quality of epoxy resin 128/MPA were texted by TGA and tensile machine. It was found that epoxy resin 128 can be cured completely with MPA under the condition of 100℃/ 2 h., 120℃/2 h and 150℃/5 h at mass ratio(epoxy resin 128∶MPA) of 1∶0.8. The shear strength of Fe-Fe of the cured product was 17.3 Mpa, 3.7 Mpa higher than epoxy resin 128/methyltetrahydrophthalic anhydride(Me-THPA)( 13.6 MPa), the thermal decomposition temperature of the cured product reached 371.5℃, about 6.1℃higher than that of epoxy resin 128/Me-THPA system(365.4℃), glass transition was 169.6℃, 55.2℃higher than that of epoxy resin 128/Me-THPA system(114.4℃). MPA showed extremely strong potential application value in electronic potting and adhesive fields. Secondly, MPA was used as material to react with diethylenetriamine, triethylenetetramine and tetraethylenepentamine respectively by amidation, and three kinds of epoxy resin polyamide curing agents were prepared in this paper, they were MPADT, MPATT and MPATP respectively. The performance of the cured products of epoxy resin 128/MPAPA systems were characterized by FT-IR, TGA and tensile machine. It was found that epoxy resin 128/MPADT, epoxy resin 128/MPATT, epoxy resin 128/MPATP systems can cured completely at mass ratio of 100∶50.8,100∶45.1,100∶45.1 (the added amount of polyamide sample W (g) correspondence to per 100 g epoxy resin is calculated according to mass ratio formula of polyamide of C36 epoxy curing agent), under the condition of 25℃for 6 h, and then 80℃for 4 h. The shear strength of epoxy resin 128/ MPADT, epoxy resin 128/MPATT, epoxy resin 128/MPATP cured systems were 21.6 MPa, 11.0 MPa, 9.3 MPa respectively. The thermal decomposition temperatures of the cured products of the three cured system were 343.0℃,341.3℃,338.8℃. The glass transition temperatures were 146.6℃,140.7℃,133.5℃respectively. MPA showed extremely strong potential application value in the field of higher level requirement to heat-resistance. At the same time, Málek method and autocatalytic mechanism were introduced to calculate the kinetic equation of resin/MPAPA, isoconversion method was used to calculate the value of activation energy, and we got the kinetic equation: dα/dt=31800000exp(54000/RT)α0.251(1-α)1.015. The results indicated that the kinetic model Sestak-Berggren provides a reasonable fitting of the experimental results with calculated values.At last, took epoxy resin 128, MPADT as matrix, silver-coated copper powder as conductive filler, KH-560 and PEG(200) as additives, we prepared two-component thermosetting conductive adhesive product, it owned excellent heat-resistance performance, and we discussed the influences of mass ratio of the components and synergism to shear strength and conductivity property, as well as evaluated the heat-resistance, glass transition and ageing-resistant property of conductive adhesive. The results showed that when the mass ratio of resin epoxy∶MPADT∶silver-coated copper powder∶KH-560∶PEG(200)= 100∶50.8∶60∶1.8∶3(it meant that the addition of MPADT was 50.8 % to epoxy resin 128, silver-coated copper powder was 60 % to resin epoxy 128, KH-560 and PEG(200) were 3 % and 5 % to silver-coated copper powder respectively). The thermal decomposition temperature was 342.1℃, and the glass transition was 144.7℃, higher than epoxy resin 128/grease-base polyamide. The shear strength and volume resistivity of conductive adhesive reduced by 18 %, 14 % respectively after psychro-thermal cycles for 150℃/40 h, -18℃/ 40 h. |
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