Structural Aspects Of Surfactants On The Stability Of Semi-Synthetic Metalworking Fluids

Most of the traditional metal cutting fluid(MCF) using mineral oil as base oil, which have poor biodegradability, and pose harm to ecological environment and the people’s health. With the rapid development of modern machinery manufacturing industry, there is a high demand for MCFs, no matter how hardly scientists do to improve the way of cutting technology and fluid feeding, or to strengthen the control and management of cutting fluid, these ways can not fundamentally eliminate the harms of cutting fluid. To solve all these problems, one ideal way is to design and develop formulations of green cutting fluids. At present, the domestic study of cutting fluid mostly focused on the modification of base oil and development of new additives, few research about the stability of micro-emulsion MCFs and the selection of surfactants compatibility well with base oil.This paper d uniform structure, the additive sensitivity is good, harmless naphthenic base oil, vegetable oil and synthetic ester with good biodegradability were used instead of mineral oil in cutting fluid in this paper, and at the same time, actively explore surfactants which have good performance and sensitivity with base oil, in this way to optimize the MCF formulas, prolong the service life of MCFs, leading to a reduction of environmental pollution and waste emissions, save energy and reduce the production cost.Different kinds of surfactants were selected to emulsify base oil (naphthenic base oil, synthetic ester, vegetable oil) and water to form micro-emulsion system, from the aspects of HLB values of surfactants, carbon chain length, number of the head groups, surfactant to oil ratio, the proportion of anionic surfactant and non-ionic surfactant and dosage of auxiliary additives and so on, exploring the effects of surfactants on the stability of micro-emulsion which consist of water, base oil and additives. Stability evaluation based on the number of stable formulation obtained, surface tensiometer, contact Angle tester, light transmittance test, dynamic laser granulometer, foam height test, through the above characterization methods to select the optimal surfactant and determine the optimal dosage of auxiliary additives.Comprehensively consider the stability of the formula number, the average particle size, and the foam height and contact Angle, get the following conclusions:(1) To get more stable naphthenic based-MCFs formulation, non-ionic surfactants with the number of head group(EO) between5-20, and the carbon chain length between12to18, paired with sodium dodecyl benzene sulfonate at low surfactant to oil ratio is preferable;(2) Non-ionic surfactants of MOA series, branched chain series, TX series surfactants with the carbon chain length less than18, and EO number between6-20and TW-80as the main emulsifier, paired with sodium dodecyl sulfate at3:1, the surfactant to oil ratio is1:1, these could have a good emulsifying effect on synthetic ester;(3) For the vegetable oil, MOA-8,1308, TX-10, SG-10, SG-40and TW-40paired with Sodium Petroleum Sulfonat and sodium dodecyl benzene sulfonate as emulsifier could have a good emulsification effect.