Microencapsulated fibers

Use Paper coating, grease-resistant coating, label varnishes, laminated board, solid-color prints, printing inks, food coatings, microencapsulation, fibers. 

Finally, PCMs [20] are becoming increasingly popular in improving comfort properties in barrier textiles such as protective or medical textiles against particles and liquids (e.g., blood) that can carry infection. Microencapsulated fibers or coat-... 

The so-called UCLA bioartificial liver involves the direct hemoperfusion of microencapsulated porcine hepatocytes in an extracorporeal chamber (Eigure 7.3). Since it permits perfusion with whole blood, it has an advantage over the hollow fiber technique that has to be perfused with plasma. The hepatocytes are isolated from pig livers and microencapsulated in an alginate-polylysine membrane. Microencapsulated hepatocytes are approximately 300 to 700 pm in diameter. 

Slow release formulations incorporate nonpersistent compounds, eg, methyl parathion, insect growth regulators, and sex pheromones, in a variety of granular, laminated, microencapsulated, and hollow-fiber preparations. 

The enhanced chemiluminescense obtained with the horseradish peroxidase-H202-luminol (139) system was applied to the development of a CLD biosensor for p-iodophenol, coumaric acid (26), 2-naphthol and hydrogen peroxide. The enzyme was immobilized by microencapsulation in a sol-gel matrix. LOD for the phenolic compounds were 0.83 p,M, 15 nM and 48 nM, respectively. A remote version of the enhanced biosensor was designed by directly immobilizing the enzyme on the tip of an optical fiber. This model was used for H2O2 assay. LOD was 52.2 p,M, with RSD 4.7% (w = 4) °. A bioluminescent response was obtained for phenols with pA a > 7 in the presence of a recombinant Escherichia coli strain, DPD2540, containing a fabA luxCDABE fusion this behavior may have analytical applications. 

HFCLM hollow-fiber contained liquid membrane MELM microencapsulated liquid membrane... 

A membrane cell recycle reactor with continuous ethanol extraction by dibutyl phthalate increased the productivity fourfold with increased conversion of glucose from 45 to 91%.249 The ethanol was then removed from the dibutyl phthalate with water. It would be better to do this second step with a membrane. In another process, microencapsulated yeast converted glucose to ethanol, which was removed by an oleic acid phase containing a lipase that formed ethyl oleate.250 This could be used as biodiesel fuel. Continuous ultrafiltration has been used to separate the propionic acid produced from glycerol by a Propionibacterium.251 Whey proteins have been hydrolyzed enzymatically and continuously in an ultrafiltration reactor, with improved yields, productivity, and elimination of peptide coproducts.252 Continuous hydrolysis of a starch slurry has been carried out with a-amylase immobilized in a hollow fiber reactor.253 Oils have been hydrolyzed by a lipase immobilized on an aromatic polyamide ultrafiltration membrane with continuous separation of one product through the membrane to shift the equilibrium toward the desired products.254 Such a process could supplant the current energy-intensive industrial one that takes 3-24 h at 150-260X. Lipases have also been used to prepare esters. A lipase-surfactant complex in hexane was used to prepare a wax ester found in whale oil, by the esterification of 1 hexadecanol with palmitic acid in a membrane reactor.255 After 1 h, the yield was 96%. The current industrial process runs at 250°C for up to 20 h. 

The term encapsulation has been used to distinguish entrapment preparations in which the biocatalyst environment is comparable to that of the bulk phase and where there is no covalent attachment of the protein to the containment medium (Fig. 6-1 D)[21J. Enzymes or whole cells may be encapsulated within the interior of a microscopic semi-permeable membranes (microencapsulation) or within the interior of macroscopic hollow-fiber membranes. Liposome encapsulation, a common microscopic encapsulation technique, involves the containment of an enzyme within the interior of a spherical surfactant bilayer, usually based on a phospholipid such as lecithin. The dimensions and shape of the liposome are variable and may consist of multiple amphiphile layers. Processes in which microscopic compart-mentalization (cf. living cells) such as multienzyme systems, charge transfer systems, or processes that require a gradient in concentration have employed liposome encapsulation. This method of immobilization is also commonly used for the delivery of therapeutic proteins. 

The entrapment method for immobilization consists of the physical trapping of the active components into a film, gel, fiber, coating, or microencapsulation (see Figure 44.5). This method can be achieved by mixing an enzyme or active molecule with a polymer and then crosslinking the polymer to form a lattice structure that traps the enzyme. Microencapsulated enzymes are formed by enclosing enzymes solution within spherical semipermeable polymer membranes with controlled porosity. 

Liu, Y. and Wang, Q. Melamine cyanurate-microencapsulated red phosphorus flame retardant unreinforced and glass fiber reinforced polyamide 66. Polymer Degradation and Stability, 91,3103-3109 (2006). 

Another application of smart materials for PPE concerns thermoregulating phase change materials. Based on microencapsulation, macroencapsulation, or solid—solid transition, this technology allows a certain level of on-demand, immediate, and powerless cooling and warming with possible recharge at room temperature. Several fiber, textile, and PPE products are already commercially available, with the addition of a fire-resistant functionality soon to come. 

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