Study On Epoxy Resin Adhensive Modified By Micro-nano Fibrils

Pure epoxy resin system has high brittleness. On the premise of maintaining or increasing the mechanical property of epoxy resin curing sample, this study aims to modify epoxy resin adhensive and enhance the flexibility of epoxy resin curing sample by utilizing natural plant fiber. The modification includes physical modification and chemical bonding modification.Utilizing bamboo pulp fiber as raw material, the study prepared micro-nano fibrils by ultracsonic-assisted degradation with sulfuric acid and achieved epoxy resin adhensive physical modified by micro-nano fibrils to full play the toughening effect of microfibril and potentiation of nanocellulose. What’s more, using microcrystalline cellulose activated by NaOH (AC-MCC) as raw material, prepared oxycellulose (TO-AC-MCC) by selective oxidation of TEMPO (2,2,6,6-Tetramethyl-l-piperidinyloxy)/NaClO/NaClO2 in the neutral medium and amino modifiying to obtain 6-amine cellulose (A-TO-AC-MCC), or prepared dialdehyde cellulose (O-AC-MCC) by sodium periodate oxidation, got the chloride of dialdehyde cellulose (Cl-O-AC-MCC) by chlorination using sulfoxide chloride, and obtained 2,3,6-amine cellulose (A-Cl-O-AC-MCC) by amino modification. In order to achieve the effect that is superior to physical modification, this study first processed the ultrasound of A-TO-AC-MCC and A-Cl-O-AC-MCC, then chemically modified epoxy resin adhensive by utilizing A-TO-AC-MCC and A-Cl-O-AC-MCC. Finally, the study analyzed cellulose fibers and epoxy resin curing samples through FESEM, Laser Particle Size Analyzer, XRD, FTIR, TG, EA, DMA and mechanical characterization, etc. The expriment result shows as follwing:(1) In the process of preparation of micro-nano fibrils by ultracsonic-assisted degradation with sulfuric acid from bamboo pulp fiber, when H2SO4 concentration is 40%, ultrasonic time is 1.5 h and micro-nano fibrils dosage is 0.75%. the mechanical properties of epoxy resin curing sample physically modified by micro-nano fibrils achieve the best. Compared with that of unmodification, the tensile strength, flexural strength and impact strength of epoxy resin sample are 31.64 MPa,54.15 MPa,28.15 KJ·m-2 and enhence 1.48%,2.46%,93.34%, respectively.(2) The optimal technology condition of selective oxidation of AC-MCC by utilizing TEMPO/NaClO/NaClO2 in the neutral medium:TEMPO dosage is 0.15 mmol/g, NaCIO dosage is 1 mmol/g, NaClO2 dosage is 12 mmol/g, oxidation at 60℃ for 8 h.(3) The optimal technology condition of selective oxidation of AC-MCC by using sodium periodate:reaction system’s pH is 4, sodium periodate dosage is 14 g, oxidation at 40℃ for 7.5 h. The aldehyde conten of O-AC-MCC is 119.33% and recovery is 64.22%.(4) In contrast to that of unmodification, when ultrasonic time is 12 h and A-TO-AC-MCC dosage is 0.50%, the tensile strength, flexural strength and impact strength of epoxy resin curing sample chemically bonding modified by A-TO-AC-MCC with 1.64% nitrogen are 35.92 MPa,62.64 MPa,31.10 KJ-m"2 and enhance 15.20%,18.52%,113.60%, respectively.(5) Compared with that of unmodification, when ultrasonic time is 4h and A-Cl-O-AC-MCC dosage is 0.50%, the tensile strength, flexural strength and impact strength of epoxy resin curing sample chemically bonding modified by A-Cl-O-AC-MCC with 15.09% nitrogen are 34.39 MPa,64.33 MPa,37.36 KJ·m-2 and improved by 10.30%,21.72%,156.59%, respectively.