摘要:

AbstractOligomers/polymers formed during the thermal‐oxidative ageing of ester‐based aviation turbine oils have been investigated, using pentaerythritol tetraheptanoate as a model ester. The principal polymer structures in the primary ageing state were revealed by means of chromatographic and spectroscopic methods. The most probable structures are dicarboxylic acid polyesters with variable amounts of α,ω‐dicarboxylic acids having chain lengths of C2up to C7The C7‐branches also contained ester‐bonded hydroxy as well as oxo substituents. Pentaerythritol triheptanoate discarboxylic acid mono esters were active precursors in polyme

ISSN:0265-6582    

DOI:10.1002/jsl.3000100102

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractIt is now recognised that, for many practical applications, an important property of a lubricant is its ability to generate thick, elastohydrodynamic (EHD) films in concentrated contacts. This paper describes a study of the EHD film‐ forming properties of polyalkylenie glycol lubricants. A wide range of polyglycol structures have been examined, with different monomer types, initiators, and molecular weights. Film thickness has been measured at several different temperatures using both conventional and ultra‐thin film interferometry. From the measured film thicknesses, the effective pressure–viscosity coefficients of the lubricants have been evaluated. This has enabled a systematic investigation of the effect of polyalkylene glycol structure on both pressure–viscosity coefficient and EHD film fo

ISSN:0265-6582    

DOI:10.1002/jsl.3000100103

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe evaluation of oil soluble polyethers (OSPs) in fully and semi‐synthetic automotive crankcase lubricants is described. Parameters including viscosity, additive compatibility, lubricity/wear performance, oxidative stability, and piston cleanliness are assessed. It is possible to formulate OSP‐containing lubricants with lower VI improver treatment level, superior viscometric properties, and Noack volatilities to comparable lubricants without OSPs. Data from engine tests and field trials show that semi‐ and fully synthetic lubricants containing OSP possess all the performance advantages of ester‐containing lubricants, with additional benefits in terms of engine and inlet system cleanliness. The results indicate that OSPs have excellent potential as synthetic lubricant base

ISSN:0265-6582    

DOI:10.1002/jsl.3000100104

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractBiodegradation test methods have been compared with regard to test conditions and test parameters. It has been shown that three methods are, in principle, suitable for non‐water soluble products. These are the Sturm test (OECD no. 301B), the MITI test (OECD 301 C), and the CEC L‐33‐T‐82 test method. A comparison in an actual test showed that the CEC test gives the highest biodegradation values, while the Sturm test and the MITI test give lower values. It is noted that the CEC test measures the amount of material used for both energy production and growth of the biomass, while the other methods measure only the material used for energy production. A possible explanation for the difference between the Sturm and the MITI test results is given. The CEC test is shown to be more suitable for the lubricant industry. Applications of biodegradable lubricants are reviewed, particularly hydraulic fluids. It is shown that rape seed oil (natural ester) and synthetic polyol esters have similarities regarding structure but also significant differences. This results in much better thermal and oxidative stability for the synthetic esters. These also offer the possibility of making a range of products of different ISO grades with similar properties.Brief consideration is given to future potential, notably for biodegradable four‐stroke lubricants. Finally, there is a timely reminder that, owing to the present limited availability of natural oils and fats and their cost, only 19% of the market for mineral oil base fluids could be replaced by natural oils and fats and their de

ISSN:0265-6582    

DOI:10.1002/jsl.3000100105

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000100106

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000100107

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000100101

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY