A Study On Factors Affecting Oxidative Aging Of Lard In Rolling Emulsion

According to the requirements of rolling lubrication,lard oil is selected to be studied and its performance is evaluated through its basic physicochemical properties,lubricity,hydrolysis stability,thermo stability and adhesion ability to steel panels.High content of linoleic acid is the key for its oxidation and polymerization at high temperature is the main reason for its better lubricity compared with the palm oil.Furthermore,because there is a great impact on the antioxidant property of the oils with different types and structures of antioxidants,the antioxidant performance of the lard oil with three types or four kinds of antioxidants is evaluated and compared by different methods,in order to explore the rules of application.When the using temperature is lower than 60?,the improved phenol antioxidants is the best;while the using temperature is higher than 90?,the sulfur ethers antioxidants should be chosen.Third,since the antioxidants in rolling lubrications would be impacted by the EP additives,the interaction of three types of phosphate-type EP additives and several kinds of antioxidants is studied.Aromatic phosphates are helpful in improving the antioxidant property.Alkyl phosphates are weaker than the aromatic phosphates,while the phosphates with EOs are the weakest.At last,for rolling emulsions,oxidation and hydrolysis are occurred simultaneously.Generally,the stability of the emulsion is decided by the type and content of the emulsifier.Different types of emulsifiers are evaluated for this purpose.For any kinds of emulsifiers,longer EO chains mean better emulsifiability.Besides,fatty alcohol type emulsifiers are far better than the NP type emulsifiers and the impact of carbon chains is little in emulsifying property for the former.