Cellulose nitrate parameter

Kinetic Parameters of Cellulose Nitrate Thermal Decomposition... 

Collection of metal complexes of the analytes on suitable adsorbing materials is often employed as an enrichment step in combination with flame methods. In a procedure proposed by Solyak et al. [20], five metals [Co(II), Cu(II), Cr(III), Fe(III), and Pb(II)] were complexed with calmagite 3-hydroxy-4-[(6-hydroxy-m-tolyl)azo]-naphthalenesulfonic acid and subsequently collected on a soluble cellulose nitrate membrane filter. In this way an effective separation from alkaline and alkaline earth metals was achieved, based on the differences in their complex formation constants and those of the transition elements. The experimental parameters were optimized for the quantitative recovery of the elements. After hot dissolution of the filter with HNO3, the analytes were determined by FAAS. Minimum detectable concentrations ranged from 0.06 pg l-1 for Cu to 2.5 pg l-1 for Cr. 

Fig. 36a and b. Second virial coefficient A2 of a) cellulose nitrate (CN) (Nc = 13.9%) and b) CN (Nc = 12.9%), in acetone78 79> O experimental data 2). Lines are calculated by using the penetration function j/ from short and long range interaction parameters A and B, which are estimated by methods 2C (full line), 2D (broken line), 2E (dotted line), and 2G (chain line), together with experimental [Pg.41]

The ability to find hundreds (or thousands) of mixtures of nonsolvents that will predictably dissolve materials in question is particularly convincing of the need for the division of cohesion energy parameters into at least three parts. Such mixtures of nonsolvents have been systematically found for such varied materials as cholesterol, cellulose nitrate, polystyrene, epoxies, etc. 

Table 5. Connection between molecular mass of ketone solvents M, degree of solvation (for cellulose nitrate) //, solubility parameter S. hydrogen bond parameter y, and dipole moment p...

The dilution ratio reveals some similarities between the solvency of different solvents. However, most measurements are restricted to cellulose nitrate, and extrapolation of the results to other binders seldom provides correct results. Furthermore the dilution ratios, unlike solubility parameters, are unable to explain several phenomena (e.g., the enhancement of the solvency of a solvent produced on adding a non-solvent). 

Figure 6-4. Dependence of the Flory-Huggins interaction parameter, x, on volume fraction, 2, of the polymer for poly(styrene) in cyclohexane and chloroform and for m-l,4-poly(isoprene) in benzene as well as for cellulose nitrate in acetone.

The cosolvency phenomenon was discovered in 1920 s experimentally for cellulose nitrate solution systems. Thereafter cosolvency has been observed for numerous polymer/mixed solvent systems. Polystyrene (PS) and polymethylmethacrylate (PMMA) are undoubtedly the most studied polymeric solutes in mixed solvents. Horta et al. have developed a theoretical expression to calculate a coefficient expressing quantitatively flie cosolvent power of a mixture (dTydx)o, where T,. is the critical temperature of the system and x is the mole fraction of hquid 2 in the solvent mixture, and subscript zero means x—>0. This derivative expresses the initial slope of the critical line as a function of solvent composition (Figure 5.4.1). Large negative values of (dT/dx) are the characteristic feature of the powerful cosolvent systems reported. The theoretical expression developed for (dT dx)o has been written in terms of the interaction parameters for the binary systems ... 

From contact-angle data in C. J. van Oss, R. J. Good, and M. K. Chaudhury, J. Chromatogr. 391,53 (1987). Note that this article quotes different calculated surface-free-energy parameters for cellulose acetate and cellulose nitrate to those in Ref. [24]. 

Golovin, V.A. and Lotmentsev, Yu.M., Investigation of structure and thermodynamie parameters of component interaction in plasticized cellulose nitrates, Vysokomolek. Soedin., 1981, vol. A23, no. 6, pp. 1310-1314 (in Russian). 

The relatively low solubility parameters (solpars) of the amorphous poly(l-olefins) have been compared with the solpars at 25°C) of other polymers poly(tetra-fluoroethylene), 13.5 poly(dimethylsiloxane) 15.5 polypropylene, 16.5 polyisobutylene, 16.5 polyethylene, 17.0 poly(ethyl methacrylate) 18.5 polystyrene, 18.5 poly(vinyl acetate) 20 cellulose nitrate, 21 poly(ethylene oxide), 24 and cellulose acetate, 24 [16]. 

Lo and Coleman [16] analysed animal tissue for arsenic using a Perkin-Elmer HGA—2100 furnace. 5g (wet weight) of tissue were mixed with 1.5 g magnesium oxide and 10 ml cellulose powder in a 100 ml beaker and charred carefully. The sample was cooled and 1.5 g magnesium nitrate added, heated to 550°C and ashed for 2h. 5 ml water was added and the sample dissolved in 45 ml 6 N hydrochloric acid. This solution was diluted 1 5 for the atomic absorption analysis to eliminate the interference signal. 10 pi was used for analysis and the parameters were as follows ... 

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