The average thickness of the grown PMMA layers is approximately of 1.9 µm. The proposed route consists in an alkali activation of titanium substrates followed by a surface initiated atom transfer radical polymerization (SI-ATRP) using a phosphonic acid derivative as coupling agent and a polymerization initiator, and a malononitrile as polymerization activator. However, currently available methods do not allow the development of thick polymeric layers, reducing significantly their potential uses. It aimed at growing thick poly(methyl methacrylate) (PMMA) layers grafted on Ti substrates to incorporate a polymer component on Ti implants. In the current study, to attenuate the stress shielding effect, a new processing route was developed. Titanium (Ti) is the most widely used metal in biomedical applications due to its biocompatibility however, the significant difference of the mechanical properties between Ti and the surrounding tissues results in stress shielding which is detrimental for load bearing tissues. Of the four primers investigated, only the NB gave improved initial strength as well as higher durability of the coating after boiling water treatment, In general, a strongly diminishing effect on the adhesion strength due to water penetration along the PEEK/SS interface followed by corrosion of the metal surface was found.įailure modes of the coated samples varied for the NB primer from cohesive failure close to the PEEK/primer interface under dry condition, to partly interfacial failure at the primer/SS interface after immersion into the boiling water for 5 h, while complete interfacial failure was found in the BP and the AEB primer cases. Subsequently, the loci of failure were determined by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) analyses. Lap shear test was used to assess both initial adhesion of PEEK to SS with and without primer, and the durability of these joints after immersion in boiling water. 4-nitrobenzene (NB), 4-benzoylbenzene (BP), benzene, and 4-(2-aminoethyl)benzene (AEB) diazonium salts, were electrografted and applied as primers on stainless steel (SS) surfaces to test the resulting bond strength and durability of a polyetheretherketone (PEEK) coating. Laser bonding is also a preferred technique for use in the United States Department of Defense "Item Unique Identification" system (IUID).In this work, a number of diazonium tetrafluroborates, i.e. The laser bonding process is outlined and specified in both military and NASA marking specifications and standards. The markings, DataMatrix two dimensional bar codes, were evaluated and found to be readable and visually looked as good as the day they were placed in orbit. The experiment was recovered on Jduring STS-114 and returned to earth on August 9, 2005. The trays were positioned on the ISS so that they could expect to receive the maximum amount of impact damage and exposure to a high degree of atomic oxygen and UV radiation. The material test coupons were then affixed to spaces provided on test panels, which were then installed onto trays which were attached to the ISS during a space walk conducted during the STS-105 Mission flown on August 10, 2001. Markings applied using a wide range of different methods and techniques, including laser bonding. In this experiment test markings were applied to coupons made of materials commonly used in the construction of the external components used on space transportation vehicles, satellites and space stations. These squares were part of the Material International Space Station Experiment, or MISSE. NASA's International Space Station, or ISS, was home to aluminum squares laser marked with CerMark® marking material for almost four years. Marks on glass have been tested for resistance to acids, bases and scratching. Markings placed on stainless steel are extremely durable and have survived such testing as abrasion resistance, chemical resistance, outdoor exposure, extreme heat, extreme cold, acids, bases and various organic solvents. The resulting marking is permanently bonded to the substrate, and in most cases it is as durable as the substrate itself. Irradiating the marking material with a laser in the form of the desired mark. The marking process generally comprises three steps:Ģ. Laser bonding materials may be applied by various methods, including a brush on technique, spraying, pad printing, screen printing, roll coating, tape, and others. Mark quality depends on a variety of factors, including the substrate used, marking speed, laser spot size, beam overlap, materials thickness, and laser parameters. 2 The durability of laser bonded markings.
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