Adhesion reduction

Undesirable adhesion to metal surfaces may cause a problem in injection molding, melt spinning, and thermoforming. In the melt spinning of PAS a variety of adhesion-related problems have been observed. These problems include the build up of polymer on spinneret surfaces resulting from both initial filament extrusion and lick-back from filament breaks. These adhesion-related problems lead to prematme spin pack failure and equipment down-time to replace spent spinneret packs, and can limit the use of PAS in certain melt spinning operations. 

A variety of lubricants and mold release agents, such as fatty acid esters and amides, have been suggested as additives to reduce the adhesion of the polymer to metal surfaces. These materials function to increase the polymer lubricity at its point of contact with a surface. In the case of PAS, conventional lubricants alone have not been found significant in reducing the adhesion problems associated with melt spinning operations. 

It has been demonstrated that PAS in melt spinning operations can be better processed by the addition of barium hydroxide, together with conventional lubricants. In fact, the barium treatment has improved the melt strength of PAS in the production of fine denier fibers. This improvement in melt strength translates to the ability to melt-spin lower molecular weight polymer.  

PPS are useful materials for electrical and electronic parts and appliances, and as high rigidity materials for various applications. In particular, PPS have found applications in technical parts such as pumps, automotive parts, printer components, and liquid crystalline display projectors. 

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Rubber adhesion experiments, performed in 1971, ° were the first quantitative demonstration of adhesion reduction by contaminants wetting the surfaces. These experiments are very readily reproducible and are described in detail next. 

In a porcine model for pelvic and para-aortic lymphadenectomy, the Iv mph nodes were removed from four anatomically defined locations on each side of the animal (Deprest, 1995). Solutions of 28% poloxamer 407 were applied to the four sites on either the left or the right side of the animal, and all sites on the opposite side were left untreated. After healing had taken place, adhesion formation at all surgical sites was evaluated, and each treated site was compared to the contralateral, untreated site. Adhesion formation was reduced at the sites treated with poloxamer 407 by approximately 40%. In a subsequent experiment, the temperature of the poloxamer 407 solution was maintained at O C during application to the injured area. Adhesion reduction improved to about 55% (Deprest, unpublished). 

Condnctive pattern imperfections such as loss of adhesion, reduction of conductor width or thickness due to nicks, pinholes, scratches, surface plating, or coating imperfections... 

Mettler, L. Effect of cross hnked sodium hyaluronate in adhesion reduction within the gynecologic surgical window. OJOG 4, 120-129 (2014)... 

The FFM results demonstrate that two PLL-g-PEG-covered surfaces under aqueous solution show substantially reduced adhesion, when compared to bare surfaces, as well as displaying reduced AF/AL values. Thus, the macrotribological behavior of PLL-g-PEG is mirrored on the nanoscale, in terms of AF/AL, with the addition of an adhesion-reduction component, which could be significant for low-load systems such as micro- or nanodevices. The FFM results also imply that it is important for both surfaces to be covered with PLL-g-PEG in order for friction reduction to be effected, and thus it is likely to be the resistance to interpenetration of two brush-... 

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