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Text | Afang
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preface
As we all know, hydrogenated butadiene brown glue has high mechanical properties, has excellent oil resistance, can be used normally between 50C-150C, excellent aging resistance, and can be used as wind power spindle sealing rubber material.
Hydrogenated butadiene rubber has unique advantages in the application of wind power sealing industry, such as better aging resistance than butadiene rubber, better low temperature resistance than fluororubber, and better dynamic mechanical properties than polygas vinegar rubber. The formula system has a comprehensive impact on the properties of hydrogenated butadiene rubber rubber, and when the filler system is used as the hydrogenated butadiene rubber reinforcement system, it has the most important impact on the mechanical properties of HNBR rubber, compression set resistance and resistance, and also has a certain impact on heat aging resistance and oil resistance.
Therefore, this paper will take you to study the application of different types of fillers in hydrogenated butadiene rubber, explore the influence of filler types on the properties of wind power spindle sealing rubber storage materials, and hope to support the development of wind power sealing industry.
Experimental part
Hydrogenated butadiene rubber, Therban C3407 diene mesh mass fraction 34%, Mooney viscosity of 70, residual double bond mass fraction of about 0.9%, density 095g/cm, German LANXESS Chemical Co., Ltd.; Carbon Black N330, Carbon Black N550 and Carbon Black N990 Shanghai Cabot Carbon Black Co., Ltd.; Precipitation silica, H-325, Shandong Lihua New Materials Co., Ltd.; kaolin, 4,000 mu Shanghai Huazhongrong Industry and Trade Co., Ltd.; Divinegar plasticizer, TP-95 Rohm and Haas Co., Ltd.; Other additives are commonly used raw materials in the commercial glue industry.
Open mill, BL6175BL Baolun Precision Testing Instrument Co., Ltd.; No Rotation Vulcanizer, UR-2010, Ucan Technology Co., Ltd.; Plate vulcanizing machine, YXC 150 Shanghai Weili Machinery Factory; High temperature test chamber WG4501 Chongqing Galaxy Test Instrument Company; Shore hardness tester, LX type A, Shanghai Liushu Instrument Factory; Thickness gauge, CH-10-AT, Shanghai Liuling Instrument Factory; Electric tensile testing machine, A1-700M Taiwan High-Tech Co., Ltd.; Abrasion testing machine, WF1689 Wanfeng Testing Equipment Co., Ltd.
Use a mill to mix the compound. Start the start-up to adjust the vial distance, cast the plastic block, thin pass 5; Enlarge the distance, add small materials after packing, mix the bottle for 3min, turn it for 3min; After eating all the powder, make the knife left and right 3-4 times; Finally, add vulcanizing agent to make knives and turn them 3-4 times; Adjust the vial 1-2 after exhausting from thin pass; Magnify the bottle distance, lower the piece, prepare the mixed rubber, and park at room temperature for 16h.
Weigh 5.0g mixed film, and use a non-rotating vulcanizer to test the positive vulcanization time of the process; Weigh about 45g of mixed film, use a plate vulcanizing machine to vulcanize the sample, the sample specification is 200mmx200mmX2mm or 200mmX200mmx3mm, the vulcanization condition is 175CX15MPaXts, the sample is parked at room temperature for 16h, spare.
Hardness according to GB/T531.1-2008 test; Tensile strength according to GB/T528-2009 test, using subbell-shaped specimen, tensile speed 500mm/min, test ambient temperature 23C Shi 2C; The tear strength is tested according to GB/T529-2008, using a right-angle specimen, the tensile speed is 500mm/min, and the test ambient temperature is 23 Shi 2C; The compression set is tested according to GB/T7759.1 to 2015 using B-type specimens (diameter (13 Shi 0.5) mm, height (6.3 Shi 0.3) mm; cylinder), test condition 100CX24h; Hot air aging performance according to GB/T35122014 test using subbell-shaped specimen test condition 100CX24: oil performance according to GBT1690-2010 test, using type specimen (25X50) 1# standard oil, test condition 100CX72h; The consumption performance is tested according to GBT1689-2014, using strip specimens, 3.2 Shi 0.2.
Study results
Figures 1 to 4 show the influence of filler types on mechanical properties, and it can be seen from Figures 1 to 4 that when carbon black is reinforced with HNBR, with the increase of carbon black particle size, the hardness of the rubber material decreases slightly, the tensile strength decreases, the tensile elongation increases, and the tear strength changes insignificantly.
When precipitation silica reinforced HNBR, the hardness and tensile strength of the rubber material are not much different from the properties of carbon black N550 reinforcing compound, but the tensile elongation of silica or kaolin reinforcing rubber is higher than that of carbon black reinforcing compound, and the tear strength is not much different from that of carbon black reinforcing compound.
Among them, silica or carbon black N550 reinforcing compound has the highest tear strength, and kaolin reinforcing compound has the lowest hardness and tensile strength. In summary, with the decrease of carbon black particle size and the increase of specific surface area, the interaction between carbon black and brown glue is enhanced, the network strength between carbon black and brown glue is enhanced, and it is not easy to slip and deform under the action of external force, and the rubber material reflects high hardness and tensile strength.
Compared with carbon black, the interaction between silica and rubber matrix is more chemical than physical adsorption to produce higher hardness and tensile strength. Kaolin has a lamellar structure, and the rubber has fewer bonding points, under the action of external force, rubber is easy to slip, divided into chain extension and lengthening, tensile strength becomes lower and tensile elongation increases.
Based on the working environment temperature of the fan spindle does not exceed 100C, the relevant experimental temperature of this test is set to 100C. Figure 5 shows the influence of filler type on the compression set of HNBR hot air, as can be seen from Figure 5, with the decrease of carbon black particle size, the hot air compression set of rubber shows an increasing trend, the reason may be that the smaller the carbon black particle size, the larger its specific surface area, the more the number of carbon black surface active points, and the more combined brown glue generated with hydrogenated butadiene rubber; Under the periodic stress and strain in the process of compression fatigue, the resistance of HNBR vulcanized rubber reinforced with small particle size carbon black is large, and the compression permanent deformation is large.
The hot air compression set of HNBR vulcanized adhesive reinforced silica or kaolin is much larger than that of carbon black reinforced vulcanized adhesive, which may be related to the "structure" of silica or the lamellar structure of kaolin. The silica-HNBR network generated by silica and HNBR is very easy to structure, and this structure is easy to be damaged and difficult to recover under the action of external force, resulting in large compression deformation of the rubber: the lamellar structure of kaolin is easy to make the combined brown glue slip in the chain under the action of external force, resulting in a large compression deformation of the rubber material.
Figures 6 to 8 show the mechanical properties of HNBR rubber after hot air aging. From Figure 6 to Figure 8, it can be seen that with the reduction of carbon black particle size, the stability performance of HNBR vulcanized rubber is enhanced after hot air aging, which may be due to the fact that the carbon black particles have more limiting groups on the surface, and the group can capture the solitary electricity formed by the free radicals generated in the early stage of aging, which is extremely unfavorable to the thermal aging stability of hydrogenated butadiene rubber: the smaller the particle size of carbon black, the larger the specific surface area, the stronger the ability to capture the solitary electricity, the better the thermal stability of HNBR vulcanized rubber.
As we all know, the main component of silica is silica, and the main components of kaolin are alumina and silica, and its bond energy is higher than that of carbon-carbon bonding energy, that is, the heat energy required when breaking is higher, and the thermal stability of its rubber material is higher than that of carbon black reinforcing compound.
Based on the fact that the lubricating oil used for the fan spindle is similar to 1# standard oil and the national standard requirements, the oil resistance test of this work selects 1# standard oil. Figs. 9 to 10 show the influence of packing species on the mechanical properties of HNBR after immersion oil. From Figure 9 to Figure 10, it can be seen that the oil resistance of HNBR vulcanized rubber supplemented by carbon black N330 or carbon black N550 is not much different; Carbon black N990, silica or kaolin reinforced HNBR vulcanized rubber has poor tensile elongation and volume change rate, which may be due to silica or kaolin particles homogeneous surface with many polar groups.
In addition, the polarity of 1# standard oil is large, and the oil resistance of the two is relatively poor according to the principle of similar compatibility. The particle size of carbon black N990 is greater than that of carbon black N330 or carbon black N550, and the amount of combined brown glue generated by it is less, and it is easy to migrate in the oil in the case of oil immersion, which eventually leads to a decrease in volume, increased hardness, and poor oil resistance.
The fan spindle has a certain speed when moving, which has high requirements for the wear resistance of HNBR seals, and it is necessary to test the wear performance of HNBR vulcanized rubber for this work. Figure 11 is the effect of filler species on the wear performance of HNBR vulcanized rubber, from Figure 11 it can be seen that with the increase of carbon black particle size, HNBR vulcanized rubber wear shows an increasing trend, the reason may be that the larger the carbon black particle size, the greater the force against the rubber chain movement, the higher the loss effect, the worse the wear resistance; Since the polar group of carbon black or kaolin particles on the surface has a strong binding effect with HNBR under the action of coupling agent, the surface adsorbs more rubber is divided under the action of external force, the higher the internal friction of rubber when the rubber is in chain movement, and the higher the loss, showing poor resistance.
conclusion
1. With the increase of carbon black particle size, the hardness of HNBR rubber material is slightly reduced, the tensile strength decreases, the tensile elongation increases, and the tear strength of carbon black N550 reinforcing rubber is the highest: the performance of silica reinforcing rubber is not much different from that of carbon black N550: the tensile elongation of kaolin or silica reinforcing vulcanized rubber is much higher than that of carbon black reinforcing vulcanized rubber.
2. With the decrease of carbon black particle size, the permanent deformation of HNBR hot air ballast shows an increasing trend: the hot air compression deformation of silica or kaolin reflexification rubber is much larger than that of carbon black reinforcement.
3. With the decrease of carbon black particle size, the thermal aging stability performance of HNBR vulcanized rubber is enhanced: the thermal stability of silica or kaolin reinforced vulcanized rubber is better than that of carbon black reinforced vulcanized rubber.
4. Carbon black N330 or carbon black N550 reinforcing vulcanized rubber has good oil resistance; Carbon black N990 silica or kaolin reinforcing vulcanized rubber has poor oil resistance.
5. With the increase of carbon black particle size, the consumption of HNBR vulcanized rubber shows an increasing trend: silica or kaolin reinforcing vulcanized rubber has poor wear resistance.