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That is, the polymer is unstable in a water based environment. This is the prevailing mechanism for the polymers degradation. This occurs in two stages. 1. Water penetrates the bulk of the device, attacking the chemical bonds in the amorphous phase and converting long polymer chains into shorter water-soluble fragments.
Vinyl polymers are subject of several structural variations, which greatly expands the range of polymers and their applications. With the exception of polyethylene, vinyl polymers can arise from head-to-tail linking of monomers, head-to-head combined with tail-to-tail, or a mixture of those two patterns. Additionally the substituted carbon center in such polymers is stereogenic (a "chiral center")
Common industry applications for PVDF thermoplastics include: [10] chemical processing, electricity, batteries and electronic components, construction and architecture, healthcare and pharmaceutics, biomedical research, ultra-pure applications, nuclear waste handling, petrochemical, oil and gas, food, beverage processing, water, wastewater ...
Bulk eroding polymers take in water like a sponge (throughout the material) and erode inside and on the surface of the polymer. Drug release from bulk eroding polymers is difficult to characterize because the primary mode of release from these polymers is diffusion. Unlike surface eroding polymers, bulk eroding polymers show a very weak ...
The modification of surfaces to keep polymers biologically inert has found wide uses in biomedical applications such as cardiovascular stents and in many skeletal prostheses. Functionalizing polymer surfaces can inhibit protein adsorption, which may otherwise initiate cellular interrogation upon the implant, a predominant failure mode of ...
The biodegradable polymers used in biomedical applications typically consist of hydrolyzable esters and hydrazones. These molecules, upon external stimulation, go on to be cleaved and broken down. The cleaving activation process can be achieved through use of an acidic environment, increasing the temperature, or by use of enzymes. [82]
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Cyclomatrix type polymers made by linking small molecule phosphazene rings together employ difunctional organic reagents to replace the chlorine atoms in (NPCl 2) 3, or the introduction of allyl or vinyl substituents, which are then polymerized by free-radical methods. [14]