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The present study is aimed at determining whether or not tribopolymerisation can occur under conditions of fretting contact. Using a high contact stress system consisting of oscillating metal balls loaded against flat steel discs, effects of various monomers on friction, wear, and surface film formation were determined. Monomers were used at 1% concentration in hexadecane. Under the conditions used (9ON load,40 Hz frequency, 300 Fm amplitude, for 1 hour), the monomers tested reduced friction or wear or both. Fourier Transform Infrared (FTIR) analysis of the test specimens showed that organic material is presented in the wear scars and depends on the metal system used, the monomer structure, location within the track, and the method of cleaning the surface after a test. With Al-on-steel, the addition of 1% styrene to hexadecane reduced volumetric wear of the disc by 65%; furthermore, positive FTIR evidence of polystyrene in the wear track was obtained. But a diner acidlglycol monomer formed metal soaps, no polymer, and had little effect on wear under these conditions. These results support the hypotheses that addition-type tribopolymerisation can be initiated by exoelectron emission. Additionally, it was found that not only does methyl methacrylate polymerise under the fretting conditions, but the polymer film formed also reacts with the friction contact surface.Taken as a whole, the results of this study of possible tribopolymerisation under fretting conditions support both major hypotheses, namely that: (i) for condensation-type monomers, the most important factor is the temperature of the rubbing surfaces. (it) For addition-type monomers, it would appear that the effect of exoelectron emission can initiate surface polymerisation even at relatively low surface temperatures, e.g., 10-40°C above ambient. This is in agreement with the negative-ion-radical action mechanism ( N I M ) of boundary lubricant component. Finally, the results obtained in this study demonstrate that the principle of tribopolymerisation developed by Furey and Kajdas can be used as a novel and effective approach to designing specific molecular structures for boundary lubrication under various rubbing conditions. Abstract tribopolymerisation, monomers, fretting, rubbing, contact, exoelectron emission. FTlRM
The present study is aimed at determining whether or not tribopolymerisation can occur under conditions of fretting contact. Using a high contact stress system consisting of oscillating metal balls loaded against flat steel discs, effects of various monomers on friction, wear, and surface film formation were determined. Monomers were used at 1% concentration in hexadecane. Under the conditions used (9ON load,40 Hz frequency, 300 Fm amplitude, for 1 hour), the monomers tested reduced friction or wear or both. Fourier Transform Infrared (FTIR) analysis of the test specimens showed that organic material is presented in the wear scars and depends on the metal system used, the monomer structure, location within the track, and the method of cleaning the surface after a test. With Al-on-steel, the addition of 1% styrene to hexadecane reduced volumetric wear of the disc by 65%; furthermore, positive FTIR evidence of polystyrene in the wear track was obtained. But a diner acidlglycol monomer formed metal soaps, no polymer, and had little effect on wear under these conditions. These results support the hypotheses that addition-type tribopolymerisation can be initiated by exoelectron emission. Additionally, it was found that not only does methyl methacrylate polymerise under the fretting conditions, but the polymer film formed also reacts with the friction contact surface.Taken as a whole, the results of this study of possible tribopolymerisation under fretting conditions support both major hypotheses, namely that: (i) for condensation-type monomers, the most important factor is the temperature of the rubbing surfaces. (it) For addition-type monomers, it would appear that the effect of exoelectron emission can initiate surface polymerisation even at relatively low surface temperatures, e.g., 10-40°C above ambient. This is in agreement with the negative-ion-radical action mechanism ( N I M ) of boundary lubricant component. Finally, the results obtained in this study demonstrate that the principle of tribopolymerisation developed by Furey and Kajdas can be used as a novel and effective approach to designing specific molecular structures for boundary lubrication under various rubbing conditions. Abstract tribopolymerisation, monomers, fretting, rubbing, contact, exoelectron emission. FTlRM
Copolymeric succinamic acid (COSMA) additives have been synthesised i n the laboratory and evaluated for their antiwear performance, both alone and in combination with zinc dialkyldithiophosphate (ZDDP) in HVI light neutral oil. COSMA additives show antiwear behaviour and, in combination with ZDDP, exhibit a good synergistic effect, reducing the wear-scar diameter by 60% and increasing the initial seizure load from Abstract 50 kg to 85-95 kg.
A new technique for improving the strength of bonded joints between various materials and different adhesives is described. Increased strength was obtained by mechanical Surface Activation Beneath Reactive Adhesives (SABRA). This technique results in higher bond energies due to the creation of free radicals. The surfaces were activated by abrasion with emery paper in the presence of the adhesive itself (epoxy), or of some suitable primer such as methyl methacrylate, acrylonitrile (AN) or hydrogen sulfide gas. The effects of this technique were demonstrated by four different methods: 1) Improved wetting of standard epoxy or water drops on the treated surface. 2) Achievement of bond energies between primers and polymeric surfaces exceeding the energy of solution in solvents, which were revealed by attenuated total reflectance infrared. 3) The detection of free radicals created by bond scission during abrasion by means of diphenylpicryl hydrazyl, (DPPH), a free radical scavenger, monitored by spec‐trocolorimetry, 4) Destructive testing of single lap joint test Pieces, scarfed tube joints and pee) test samples. These experiments will be described in a second paper. The theoretical base of the new approach is supported by a tentative estimate of energies set free by mechanochemical creation of free radicals and the excess heat released during abrasion.
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