【作者】 李清华；

【导师】 陶德华； 张建华；

【作者基本信息】 上海大学 ， 机械设计与理论， 2009， 博士

【摘要】 植物油润滑性能优良、可资源再生,易生物降解,是良好的环境友好润滑材料,但由于植物油分子中含有双键,氧化稳定性差,且低温流动性差,限制了其作为润滑油的实际应用。本文针对植物油的这两个缺陷,通过化学改性对其性能进行了改进。1.通过优化合成条件合成了菜油乙酯,菜油乙酯氧化易生成油溶性线型聚合物,抗油泥性得到了明显改善,但双键还没消除,易氧化问题还没得到完全解决。菜油乙酯的粘度指数很高(VI≥200),可以作为润滑油粘度指数改进组分。2.采用环氧化异构酯化工艺合成了一系列不同烷链的改性豆油,双键得到了饱和,氧化稳定性得到了改善。它们的粘度指数较高(VI107～132),粘温性好,而倾点(-4～-12℃)没有得到明显改善。随烷链链长增长,改性豆油的运动粘度降低(豆油异构丁酯的粘度小于己酯),粘度指数增大。系列改性豆油中豆油异构丙酯综合性能最佳,通过优化实验条件得到的豆油异构丙酯的性能:V40℃=1145 mm2/s,VI为114,倾点-12℃,PB744.8N, D294N30 ’0.52mm,其摩擦学性能优于豆油。通过磨斑形貌分析发现豆油异构乙酯润滑的钢球磨斑表面光滑,磨痕浅且尺寸较小,抗磨性能优于以矿物油250BS和豆油。通过AES分析和XPS分析结合现代反射红外分析对它们的摩擦学机理进行了探讨。3.采用环氧化、酯交换和异构醚化新型工艺合成了一系列不同烷链结构的改性菜籽油,双键得到了饱和,氧化稳定性得到改善。它们的粘度指数较高(VI117～149),粘温性好,倾点在-6～-29℃之间,部分改性菜籽油的低温性得到明显改善。改性菜籽油的粘度指数随着脂肪醇链长的增加而增大,在相同链长的情况下随支链化(异构化)程度的增加而降低;改性菜籽油的倾点随着直链醇链长的增加倾点升高,而随着支链醇链长的增加倾点降低;改性菜籽油的抗磨性随链长的增加而增强,链长相同的随分子支链化(异构化)程度增加而降低。异辛醇改性菜籽油的综合性能最佳,通过优化条件实验得到的异辛醇改性菜籽油的性能:V40℃=25.20 mm2/s,VI为140,倾点-29℃,PB862.4N,D294N30 ’0.50mm。由异辛醇改性菜籽油润滑的钢球磨斑,磨痕浅且尺寸较小,优于以菜籽油和32#机油为润滑剂的钢球表面,通过AES分析探讨了它们的抗磨机理。4.采用环氧化、酯交换和异构醚化工艺合成了改性蓖麻油1#,饱和了双键,氧化稳定性得到改善;改性蓖麻油1#通过优化条件实验异构酯化合成了改性蓖麻油2#,氧化稳定性得到进一步提高。改性蓖麻油1#性能:V40℃=90.12 mm2/s,VI为105,倾点-46℃,PB785.0N,D294N30 ’0.44mm;改性蓖麻油2#性能:V40℃=64.16 mm2/s,VI为117,倾点-58℃,PB695.8N, D294N30 ’0.57mm。改性蓖麻油的粘度指数和倾点得到明显改善,改性蓖麻油的粘度指数和倾点得到明显改善,其低温性能超过了市售的季戊四醇酯。改性蓖麻油2#的倾点和粘度指数优于改性蓖麻油1#,有着更广泛的应用前景。改性蓖麻油1#润滑的钢球磨斑,表面较光滑且尺寸较小,优于蓖麻油,而改性蓖麻油2#的抗磨性能反而降低,通过AES分析对它们的抗磨机理进行了探讨。根据L-33-A-93试验方法对豆油异构丙酯、异辛醇改性菜籽油和改性蓖麻油2#的生物降解性进行了考察,发现其生物降解性好,达到了德国“蓝色天使”的标准,是可生物降解的润滑油。对豆油异构丙酯和改性蓖麻油2#的应用性可行性进行了初步探讨。豆油异构丙酯具有很高的粘度,可以代替光亮油与低粘度的润滑油混合调配各种粘度的润滑油。豆油异构丙酯与低粘度聚醚调配的各粘度级别的润滑油低温流动性和摩擦学性能优于同级别矿物油,并具有很好的氧化稳定性,可用作高档次合成润滑油。改性蓖麻油2#的倾点低于-55℃,低温性能和氧化稳定性优良,应用前景广泛,以改性蓖麻油2#为基础油研制的两种新型航空涡轮发动机油基本能够达到或接近MIL-L-7808L的规范要求,可望能够应用在航空涡轮发动机中。更多还原

【Abstract】 Vegetable oils are environmentally friendly base stocks and renewable feedstocks. They have excellent lubricity and biodegradability. However their practical application is limited because of the poor oxidative stability (there are double bonds in the molecular) and bad low-temperature fluidity. So we improved the oxidative stability and low-temperature fluidity of vegetable oils through chemically modification in this paper.1. Rapeseed oil ethyl ester was synthesized through optimizing test. They produce oil-soluble linear polymer after oxidized, so their oily sludge content is obviously less than rapeseed oil. However they still have double bounds in the molecule. Rapeseed oil ethyl ester with high viscosity index value (VI≥200) can be used as VI improve portion.2. A series of chemically modified soybean oils were synthesized by epoxidizing soybean oil and different carbon chain length fatty acids (which can saturate the double bonds to enhance the oxidative stability). They have high viscosity index(VI107～132), good viscosity-temperature characteristics, however their pour point(-4～-12℃) no obvious improve. The chemically modified soybean oils with different acyl chain length have different viscosity, and the higher the viscosity is, the better lubrication characteristics become. The propionyl-chemically-modified soybean oil synthesized through optimizing test has the best integrative characteristics: V40℃=1145 mm2/s,VI 114,pour point is -12℃,PB744.8N,D294N30 ’0.52mm. The wear scare based on acetyl-chemically-modified soybean oil is smoother, leveler and smaller than 250BS and soybean oil. The tribological mechanism of them was discussed through AES and XPS analysis combined with reflectance IR spectrum analysis.3. A series of chemically modified rapeseed oils were synthesized by epoxidizing rapeseed oil and different carbon chain alcohols (which can saturate the double bonds to enhance the oxidative stability). They have high viscosity index(VI107～132), good viscosity-temperature characteristics, pour point is between -6～-29℃. The pour point of iso-octanol modified rapeseed oil (-29℃) is obviously improved. The pour point of chemically modified rapeseed oils increases with the length of carbon chain of linear alcohol, and gradually decreases with the degree of isomerization of the molecule; the tribological characteristics increase with the length of carbon chain decrease with the degree of isomerization at the same length of carbon chain. The iso-octanol modified rapeseed oil has the best integrative properties of the chemically modified rapeseed oils (V40℃=25.2mm2/s, VI 140, pour point is -29℃, PB 862.4N, D294N30 ’0.50mm). The wear scare based on iso-octanol modified rapeseed oil is smoother, leveler and smaller than 32# mineral oil and rapeseed oil, and the tribological mechanism of them was discussed through AES analysis.4. The chemically modified castor oil 1 was synthesized by epoxidizing castor oil and iso-octanol (which can saturate the double bonds to enhance the oxidative stability). And the chemically modified castor oil 2 ( V40℃=64.16 mm2/s,VI 117,pour point is -58℃,PB695.8N, D294N30 ’0.57mm) was synthesized by chemically modified castor oil 1(V40℃=90.12 mm2/s,VI 105,pour point is -46℃,PB785.0N,D294N30 ’0.44mm) and acetic anhydride. The viscosity index and pour point of these two kind of chemically modified castor oils were improved, even be better than which of pentaerythritol ester of market Selling. The viscosity index and pour point of chemically modified castor oil 2(VI 117, P.P. -58℃) is better than chemically modified castor oil 1(VI 105, P.P. -46℃). The wear scare based on chemically modified castor oil 1 is smoother, leveler and smaller than castor oil, however which of chemically modified castor oil 2 is worse than castor oil, the tribological mechanism of them was discussed through AES analysis.Biodegradability of propionyl-chemically-modified soybean oil, iso-octanol modified rapeseed oil and chemically modified castor oil 2 was evaluated according to L-33-A-93, they are biodegradable lubricants because their biodegradability can satisfy the norm of German“Blue Angle”.The feasibility of application of propionyl-chemically-modified soybean oil and chemically modified castor oil 2 was evaluated. The propionyl-chemically-modified soybean oil with high viscosity, could be used to blend the lubricating oils with diversified viscosity levels instead of bright stock. These blended lubricating oils, prepared by propionyl-chemically-modified soybean oil and polyether, have low pour point, good tribological characteristics, and excellent oxidation stability, which can be used as high-grade synthetic lubricant. The chemically modified castor oil 2 has excellent low-temperature property and oxidative stability, which have the wide application prospect. The aviation turbine engine lubricating oils based on chemically modified castor oil reach or close to the norm of MIL-L-7808L, which could be applied in aviation turbine engine.更多还原