Liquid encapsulation

Fergason J L 1984 Encapsulated liquid crystal and method US Patent 4 435 047... 

R.K. Lund, Encapsulated Liquid Monopro-pellant Ammunition Feasibility Study , Thiokol... 

The following Add ft Pjsfs are of limited distribution 1) G.A. Yanyecic, Decomposition Characteristics of Nitrate Ester Monopropellants , Rept No TM-705. 9161-03, Contract NOW-65-0123, Penn State Univ, Univ Park (1968) 2) R.K. Lund, Encapsulated Liquid... 

Monomers of die type Aa B. are used in step-growth polymerization to produce a variety of polymer architectures, including stars, dendrimers, and hyperbranched polymers.26 28 The unique architecture imparts properties distinctly different from linear polymers of similar compositions. These materials are finding applications in areas such as resin modification, micelles and encapsulation, liquid crystals, pharmaceuticals, catalysis, electroluminescent devices, and analytical chemistry. 

Lund, Encapsulated Liquid Monopropellant Ammunition Feasibility Study , Eglin AFB Tech Rept AFATL-TR-61-27 by Thiokol Chemical Corp, Wasatch Division, Brigham City, Utah (1968) 26) R.F. Fletcher, Ann-... 

Microcapsules arc used in several film coatings other than carbonless paper. Encapsulated liquid crystal formulations coated on polyester film arc used to produce a variety of display products including ihcrmomelers. Polyester film coated with capsules loaded with leuco dyes analogous to those used in carbonless copy paper is used as a means of measuring line and force pressures. Encapsulated deodorants that release their core contents as a function of moisture developed because of sweating represent... 

The landmark discovery of liposomes by A. D. Bangham in the early 1970s [95] sparked intense interest in them by the scientific community. Because of their similarities to biological membranes, they are used in model studies of cell-cell interactions as well as interactions between membranes of eucaryotic organelles. Furthermore, their ability to stably encapsulate liquid solutions has enabled their... 

Figure 1. Schematic representation of operation of heterogeneous liquid crystal light shutters A) glass beads in a liquid crystal film, B) liquid crystal imbibed in a microporous film, C) encapsulated liquid crystal, D) polymer dispersed liquid crystals.

Liquid Membranes Emulsion liquid-membrane (ELM) extraction involves intentional formation of an emulsion between two immiscible liquid phases followed by suspension of the emulsion in a third liquid that forms an outer continuous phase. The encapsulated liquid and the continuous phase are miscible. The liquid-membrane phase is immiscible with the other phases and normally must be stabi-... 

The problem appears somewhat more complicated in the case of nanocapsules, where one deals with at least three different structural elements a continuous liquid phase, the solid phase represented by the capsule walls and the encapsulated liquid domain All techniques mentioned so far only allow for the differentiation of the solid phase from the two liquid phases. An example for poly-w-butylcyanoacrylate nanocapsules in aqueous dispersion is shown in Figs. 15 and 16. 

This simple example shows the principle how PFG experiments can be used to discriminate the encapsulated liquid components against the ones occurring in the continuous phase. However, the real potential of the PFG experiment is established when studies are extended to time-resolved processes or to the observation of molecular exchange across the domain limits (see Section 4.5). 

In these expressions, p is the porosity of the SiC, i.e. the volume fraction of empty space. In the asymmetric MG model, we have chosen the coating to be the solution, since the opposite choice of SiC-encapsulated liquid spheres will not permit diffusion through the medium. With this choice, the SiC does not percolate and hence there is no structural support. The selectivity of the membrane is based in part on the size and shape of the protein molecules. The expressions for (pD)eff in the effective medium models [Equations (12.2) and (12.3)] do not contain a size scale, but it is necessary to introduce a scale in order to account for the size of a protein molecule. For simplicity, we assume that the proteins are spherical with effective (hydration) radius r. The excluded volume within the pores due to nonzero size is taken into account by replacing the porosity p with an effective porosity p. For the columnar... 

In general, the term liquid crystal is used to describe an intermediate phase between liquid and solid occurring in some organic compounds. The phase of liquid crystal can be divided into two mesophases smectic and nematic. Nematic liquid crystals can be further divided as chiral nematic or archiral nematic. In chiral nematic liquid crystals, sterol-related compounds are called cholesteric, and non-sterol-based compounds are termed chiral nematic. For heat transfer applications, encapsulated forms of chiral nematic [71] or the composite liquid crystal sheets of the cholesteric type [72] are commonly used. Recently, the application of micro-encapsulated liquid crystals has become more popular in heat transfer measurements because of the fast response and easy paintbrush or spray application to the test surface. 

The concentration gradient of the encapsulated liquid is directed from the periphery to the center of the film cross-section (Fig. 2.28). 

The number of methods for chemical encapsulatiod is actually far less. They are necessary because they are very effective in encapsulating liquids and small core sizes. In particular, it is possible to encapsulate flavors and fragrances down to lOjum in size. 

Fig. 16 Capsule formation by phase separation, (a) Scheme a solution of monomer and hydrophobic oil (ie/t) is dispersed in an aqueous surfactant solution middle). Phase separation between the growing polymer and the oil occurs, leading to core shell morphology with encapsulated liquid, (b) Nanocapsules with hexadecane by phase separation [35]. (c) Encapsulation of Lucirin TPO [173] and (d) the fragrance 1,2-dimethyl-1-phenyl-butyramide [174]...

Besides the radical and anionic polymerization at the interface, polyaddition reactions can also be carried out at the droplet s interface. This technique can be realized in direct and inverse miniemulsion which enables the encapsulation of either hydrophobic or hydrophilic liquids. It is important to mention that the encapsulated liquids have to be a non-solvent for the generated polymer shell if capsules are the desired morphology. 

The use of flavors in food that were encapsulated goes back to the 1960s and 1970s where tobacco manufacturer tried to enhance cigarette filters with various devices that encapsulate liquid... 

Blagdon PA, Morgan R. Methods of encapsulating liquids in fatty matrices, and products thereof. US patent 5204029, 1993. 

Another way of facilitating the incorporation of flame-retardants into a polymer system is to encapsulate liquid agents, forming powder-like products (with an average particle size of about 30 jum), such as Phoenix ISO-2 A and ISO-2 B of Insulated Technologies, recommended for polyurethane and styrenic foams. ... 

UF microcapsules containing DCPD have been prepared by in-situ polymerization in an oil-in-water emulsion [66]. Different experimental parameters such as agitation speed, temperature and pH have been studied in order to obtain microcapsules with a long shelf-life - that is, microcapsules which are impervious to leakage and diffusion of the encapsulated (liquid) heahng agent for a considerable time. 

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