Post-Processing Infiltration

Printing processes may include a post-processing infiltration step in order to increase the strength of the printed article using two-component casting resins or adhesives or one-component cyanoacrylate adhesives to achieve greater durability in a three-dimensional article (17). 

Further, they may be infiltrated with a liquid plasticizer to obtain strengths comparable to that of articles formed with cyanoacrylate 

The usage of infiltrant materials for plasticized sintering may provide some advantages over conventional methods. The plasticizer may be ethanol, benzene sulfonamide or propylene carbonate. 

An extremely high solubility of the polymer in plasticizer may be undesirable because it may result in over-plasticization or the dissolution of the thermoplastic additive. In that case, the glass transition temperature may be close or below room temperature, which may cause distortion and weak particle bonding. The plasticizer material may be preferably selected from materials that have low solubility at room temperature but greater solubility at higher temperatures. To reduce the solubility, the plasticizer may be diluted either by a solvent that is removed after sintering or an inert solid material that may remain in the three-dimensional article after cooling. 

Using two-component casting resins such as epoxy-amine, isocyanate-amines, or isocyanate-polyol systems decreases the ease of use for the end-user by incorporating extra mixing steps, imposing pot-life constraints, and giving rise to safety, health, and environmental issues. 

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The presence of this minor amount of residual material was probably responsible for the slight residual cellular infiltrations seen at these periods. The polymers in this study were carefully characterized regarding molecular weight, monomer content, and residual ethylene oxide levels both pre- and post-processing. Specifications were strictly enforced for this study and may account for the excellent tissue response observed. 

Recently, it was described the generation of CTL epitopes by post-translational protein splicing, a process previously observed only in plants and unicellular organisms. Hanada et al. [303] demonstrated that the NTYASPRFK peptide, recognized by a CTL clone isolated from human CTLs infiltrating a renal cell carcinoma. 

During this very long time period, processes may occur under the impact of changing hydrochemical conditions that lead to a new phase of contaminant mobilization. It is easy to visualize how a process may be initiated when oxidized precipitation infiltrates a post-methanogenic landfill body and a front of increased metal concentrations moves toward the groundwater over a long period of time as a consequence of dissolution and precipitation reactions (Fbrstner et al. 1987). This possibility of metal mobilization from reactor landfills should always be considered when low-organic hazardous waste is deposited, especially if it contain sulfides or easily soluble components. 

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