| In this thesis,cyanate ester,bismaleimide resin and cyanate ester/bismaleimide resin were used to modify the heat resistance of acrylate anaerobic adhesives by physical blending method,and the modification effect and modification mechanism of cyanate ester,bismaleimide resin and blended resin on the adhesive performance and thermal stability of anaerobic adhesives were investigated.The main conclusions are as follows:(1)In the anaerobic adhesive systems modified by phenolic cyanate(NCE)or bisphenol E cyanate(ECE),the cyanate resins were found to be more compatible with acrylate monomers and formed homogeneous structures as shown by DMA and SEM characterization.The torque strength of the modified anaerobic adhesive was lower than that of the unmodified anaerobic adhesives under room temperature conditions.After heat treatment,the thermal strength of anaerobic adhesives modified by 30 parts NCE at 180℃increased by 123.15%compared with unmodified anaerobic adhesives;.The maximum torque of anaerobic adhesive modified by 10 parts of NCE increased by45.37%after heat treatment at 180℃.The torque strength of anaerobic adhesive modified by NCE was higher than that of anaerobic adhesive modified by ECE.As shown by thermogravimetric analysis(TG),after heat treatment at 180℃,the T_d5%of the anaerobic adhesive modified by 100 parts of NCE addition was 388.11℃,which was 85.74℃higher than that of the unmodified anaerobic adhesive.Characterization by differential scanning calorimetry(DSC)and infrared spectroscopy(IR)showed that the degree of curing of acrylate monomer increased with the increase of heat treatment temperature,cyanate formed a triazine ring structure with the increase of heat treatment temperature.After heat treatment at 180℃,the acrylate basically reacted completely and cyanate had a small amount of incomplete reaction.(2)In the anaerobic adhesive system modified by m-phenylene propylene bismaleimide(PDM)and diphenylmethane bismaleimide(BDM),bismaleimide and acrylate monomer were in a split-phase state as shown by DMA and SEM characterization.The torque strength of the bismaleimide resin modified anaerobic adhesive was higher than that of the unmodified anaerobic adhesive under room temperature conditions.After heat treatment,the thermal strength of anaerobic adhesive modified by 40 parts of PDM at 180℃increased by 207.91%,compared with that of unmodified anaerobic adhesive.After heat treatment at 250℃,the maximum torque of anaerobic adhesive modified by 30 parts of PDM increased by18.81%.The torque strength of anaerobic adhesive modified by PDM was higher than that of anaerobic adhesive modified by BDM as a whole.After heat treatment at180℃,the T_d5%of the modified anaerobic adhesive modified by 40 parts of PDM addition was 364℃,which was 81.86℃higher than that of the unmodified anaerobic adhesive.The DSC and IR characterization showed that the unsaturated groups of acrylate and bismaleimide further reacted and the degree of curing increased with the increase of heat treatment temperature,and the reaction between PDM and acrylate was basically complete after heat treatment at 180℃.(3)In the anaerobic adhesive system modified by NCE and PDM together,the PDM heat-resistant resin is in a split-phase state as shown by DMA and SEM characterization in the system.At room temperature,the breakaway torque and prevailing torque of the co-modified anaerobic adhesive with 30 parts of cyanate ester and bismaleimide ester addition were increased by 3.56%and 8.47%.After heat treatment,the breakaway torque and prevailing torque of the co-modified anaerobic adhesive with 180℃thermal strength were increased by 64.53%and 59.55%,compared with the unmodified anaerobic adhesive.After heat treatment at 180℃,the T_d5%of the co-modified anaerobic adhesive was 371.20℃which was 68.83℃higher than that of the unmodified anaerobic adhesive.The DSC and IR characterization showed that the degree of curing of the components in the system increased with the increase of the heat treatment temperature. |
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