Ethyl cellulose polymer properties

Cellulosic They are tough, transparent, hard or flexible natural polymers made from plant cellulose feedstock. With exposure to light, heat, weather and aging, they tend to dry out, deform, embrittle and lose gloss. Molding applications include tool handles, control knobs, eyeglass frames. Extrusion uses include blister packaging, toys, holiday decorations, etc. Cellulosic types, each with their specialty properties, include cellulose acetates (CAs), cellulose acetate butyrates (CABs), cellulose nitrates (CNs), cellulose propionate (CAPs), and ethyl celluloses (EC). 

Many PSPs are composed of probe dyes, such as polycyclic aromatic hydrocarbons (e.g., pyrene) and coordination compounds (e.g., platinum por-phryins and ruthenium(II) polypyridyl complexes) immobilized in various gas permeable polymer films such as silicon polymer, organic glassy polymers (e.g., poly(methylmethacrylate), polystyrene), fluorinated polymers, or cellulose derivatives such as ethyl cellulose [9,10]. As probe molecules interact with polymer matrices directly, the properties of PSPs strongly depend on the properties of polymer matrices. The oxygen permeability of polymer matrix is an especially important factor for highly sensitive PSP. 

Using tensile testing of free films, researchers have shown that plasticizer type and concentration influence the mechanical properties of both acrylic and cellulosic polymers. ° Fig. 10 shows the influence of dibutyl sebacate concentration on the tensile properties of free ethyl cellulose films. ° As the concentration of the... 

Guo, J.X. Gray, D.G. Effect of degree of acetylation and solvent on the chiroptical properties of lyotropic (acetyl)(ethyl) cellulose solutions. J. Polym. Sci. B Polym. Phys. 1994, 32 (15),... 

Dai, Q.G. Gilbert, R.D. Khan, S.A. Kadla, J.F. Relaxation behaviors of lyotropic (acetyl)(ethyl) cellulose/acrylic acid solutions with different chiro-optical properties. Polym. Preprints (ACS, Div Polym. Chem.) 2004, 45 (1), 824-825. Shimamoto, S. Uraki, Y. Sano, Y. Optical properties and photopolymerization of liquid crystalline (acetyl) (ethyl) cellulose/acrylic acid system. Cellulose 2000, 7 (4), 347-358. 

In this paper the solution properties of a spectrum of mobility control polymers have been compared. Polysaccharides, polyacrylamides, and hydroxy ethyl cellulose show vastly different solution behavior. Despite this, the properties investigated can be correlated by noting one molecular characteristic of these polymers, namely molecular size. 

Polymers that have been suggested for mobility control in oil reservoirs include polyacrylamides, hydroxy ethyl cellulose, and modified polysaccharides which are produced either by fermentation or by more conventional chemical processes. In this paper the solution properties of these polymers are presented and compared for tertiary oil recovery applications. Among the properties discussed are non-Newtonian character for different environmental conditions (electrolytes and temperature), filterability, and long term stability. The behavior of these water soluble polymers in solution can be correlated with the effective molecular size which can be measured by the intrinsic viscosity technique. A low-shear capillary viscometer with a high precision and a capability of covering low shear rates (such as 10 sec - - for a 10 cp fluid) has been designed to measure the viscosities. The measurement of viscosities at such slow flow conditions is necessitated... 

The two major commercial organosoluble cellulose ethers, ethyl-cellulose and ethyl(hydroxyethyl)cellulose (EHEC), are filmforming polymers distinguished by unusual properties and versatility (22). They contribute to the basic film properties of special types of inks, coatings, and adhesives. Their special utility results from the following performance properties (23) ... 

L1Y Li, Y., Liu, R., Liu, W., Kang, H., Wu, M., and Hrrang, Y., Synthesis, self-assembly, and thermosensitive properties of ethyl cellulose-g-p(PEGMA) amphiphilic copolymers,/. Polym. Sci. Part A Polym. Chem., 46,6907, 2008. 

Po ly (cap ro lac tone) and ethyl cellulose were obtained from Aldrich, and were used as received. They are seml-crystalllne materials and would be expected to exhibit localized changes In elastic properties at both and the melting point, T,. Physical parameters for these polymers were obtained from the Aldrich catalog. No value was available for the of PCAP the value In Table II Is estimated using the relationship... 

Frequently the polymers found in nature or made commercially need some improvements in their end-use properties for specific applications. In such cases, modification reactions can be made on the polymers. A notable case is cellulose, which is insoluble in water and in most organic solvents. Suitable reactions are done industrially to convert it to esters or ethers. Sachinvala et al. have synthesized a number of di- and tri-substituted cellulose ethers and characterized them by NMR (64). Xu et al. have used 2D NMR to analyze ethyl cellulose, a commercial polymer (65). Newmark has used 2D NMR to study cellulose acetate butyrate (54). Other uses of NMR to study polymer reactions have been reviewed elsewhere (129). 

Ethyl cellulose exhibits the best properties within the family and is highly exploited. In conclusion, the cellulose family played a significant role at the beginning of the polymer era, but now the younger polymers with improved properties and workability, as well as availability of raw materials for mass production, compete successfully. 

Many cellulose derivatives form lyotropic liquid crystals in suitable solvents and several thermotropic cellulose derivatives have been reported (1-3) Cellulosic liquid crystalline systems reported prior to early 1982 have been tabulated (1). Since then, some new substituted cellulosic derivatives which form thermotropic cholesteric phases have been prepared (4), and much effort has been devoted to investigating the previously-reported systems. Anisotropic solutions of cellulose acetate and triacetate in tri-fluoroacetic acid have attracted the attention of several groups. Chiroptical properties (5,6), refractive index (7), phase boundaries (8), nuclear magnetic resonance spectra (9,10) and differential scanning calorimetry (11,12) have been reported for this system. However, trifluoroacetic acid causes degradation of cellulosic polymers this calls into question some of the physical measurements on these mesophases, because time is required for the mesophase solutions to achieve their equilibrium order. Mixtures of trifluoroacetic acid with chlorinated solvents have been employed to minimize this problem (13), and anisotropic solutions of cellulose acetate and triacetate in other solvents have been examined (14,15). The mesophase formed by (hydroxypropyl)cellulose (HPC) in water (16) is stable and easy to handle, and has thus attracted further attention (10,11,17-19), as has the thermotropic mesophase of HPC (20). Detailed studies of mesophase formation and chain rigidity for HPC in dimethyl acetamide (21) and for the benzoic acid ester of HPC in acetone and benzene (22) have been published. Anisotropic solutions of methylol cellulose in dimethyl sulfoxide (23) and of cellulose in dimethyl acetamide/ LiCl (24) were reported. Cellulose tricarbanilate in methyl ethyl ketone forms a liquid crystalline solution (25) with optical properties which are quite distinct from those of previously reported cholesteric cellulosic mesophases (26). 

This exclusion of polymers from the interior of the vesicles results in an osmotic compression of the water layers and a decrease in the water layer thickness and lamellar phase volume. This effect allows the control of bulk properties such as viscosity and also provides a probe of water layer dimensions in lamellar dispersions. The lamellar surfactant system used in this study is the sodium dodecyl sulfate (SDS)/dodecanol (Ci20H)/water system that has been used to prepare submicron diameter emulsions (miniemulsions) from monomers for emulsion polymerization (5) and for the preparation of artificial latexes by direct emulsification of polymer solutions such as ethyl cellulose (4). This surfactant system forms lamellar dispersions (vesicles) in water at very low surfactant concentrations (< 13 mM). 

Dibutyl sebacate (DBS) n. (CH2)s (COO C4H9)2. a plasticizer, one of the most effective of the sebacate family. It has good low-temperature properties, low volatility, and is compatible with vinyl chloride polymers and copolymers, polyvinyl butyral, and ethyl cellulose. It is non-toxic, suitable for uses in food wrappings. 

The surface properties of a coated matrix can have a significant effect on the test s performance. Water soluble polymers and polymeric surfactants are used considerably to achieve the desired results. Water soluble polymers and surfactants can be used to control the rate of wetting and the release of reactants from different zones in multi-layered systems. Faster wetting of the strips could also mean a reduction in the overall test time. Polyvinyl pyrrolidone, polyvinyl alcohol, polyacrylamides, polyethylene glycol, ethyl cellulose, and hydroxypropyl methyl cellulose are some of the commonly used water soluble polymers. 

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