Polymers values

The many commercially attractive properties of acetal resins are due in large part to the inherent high crystallinity of the base polymers. Values reported for percentage crystallinity (x ray, density) range from 60 to 77%. The lower values are typical of copolymer. Poly oxymethylene most commonly crystallizes in a hexagonal unit cell (9) with the polymer chains in a 9/5 helix (10,11). An orthorhombic unit cell has also been reported (9). The oxyethylene units in copolymers of trioxane and ethylene oxide can be incorporated in the crystal lattice (12). The nominal value of the melting point of homopolymer is 175°C, that of the copolymer is 165°C. Other thermal properties, which depend substantially on the crystallization or melting of the polymer, are Hsted in Table 1. See also reference 13. 

Table 5.11 Permeability data for various polymers values for P X 10 cm- s mm cm cmHg...

Physical and Chemical Properties - Physical State at 15 V and I atm. Solid Molecular Weight Values for anhydrous salt run from 120 to high polymer values Boiling Point at I atm. Not pertinent (decomposes) Freezing Point Not pertinent Critical Temperature Not pertinent Critical Pressure Not pertinent Specific Gravity 1.8-2.5 at 25 °C (solid) Vtpor (Gas) Specific Gravity Not pertinent Ratio of Specific Heats of Vapor (Gas) Not pertinent Latent Heat of Vaporization Not pertinent Heat of Combustion Not pertinent Heat of Decomposition Not pertinent. 

For many polymers it has been found that C1 and C2 are constants and Tref is taken asT, the glass transition temperature for the polymer (values are given in Table 1.8). The WLF equation then takes the form... 

Polymer Estimated Production, 1,000 tons Estimated Average Price, cents/lb Value, S million Portion of Total Polymer Value, %... 

Off-Line Mw Measurements in Several Solvents. Table 1 shows results oT din/dc (column 3T and off-line Mw measurements (column 6) which were carried out in THF, toluene, and chloroform. The dn/dc also was calculated via Equation lb using the weight fraction of each monomer (from proton NMR, "Experimental") and the dn/dc for the corresponding homo polymers. Values of the homopolymers in THF styrene (0.190), isoprene (0.127), butadiene (0.132) toluene styrene (0.108), isoprene (O.O3I), butadiene (0.032) chloroform styrene (0.155), isoprene (0.093), butadiene (0.094). Values of dn/dc derived in this manner are presented in column 4. 

Despite the proximity of flow curves, as well as values r) and 0 for these polymers (values r 0 and 0 are usually subject to dimensionless representation, normalization ofo0 and t), the time during which the maximum possible strain is attained In max = 2.8 for polyethylene and exceeds that of polyisobutylene at the same o0 by factor of 6. In this case the dependency In e(t) in the region of measurement for polyisobutylene is characterized by increasing strain velocity x = d(ln e)/dt in contrast to which x(t) decreases strictly in low-density polyethylene within a significant section of s and becomes approximately constant at high values of t. 

This value is, therefore, mentioned as the theoretical maximum of a it remains an open question what the significance of V is in such a case, thinking of our spheres For liquid-crystalline polymers values round a = 1.5 are indeed being found. 

Acrylic fibers are vinyl polymers valued for resistance to chemical and biological degradation. Acrylonitrile (or vinyl cyanide) forms a homopolymer that is used in filters and artificial wool, which is widely used in sweaters. 

Here no attempt at a general survey will be made, but only a specific example of polyelectrolyte behaviour will be given, viz. the viscosity data on solutions of poly(acrylic acid). For this polymer, values of a and K can be found in the literature for different values of a, and I. 

For a number of linear polymers, values of E for single crystals have been determined. This has been performed by direct measurements or by calculation from molecular dimensions and force constants for bond stretching and valence angle deformation (Treloar, 1960 Frensdorff, 1964 Sakurada and co-workers, 1962, 1970 Frank, 1970). 

TABLE 18.13 Dual mode sorption and mobility data of glassy amorphous polymers (values at 35 °C) Data from Sada et al. (1987), Chern et al. (1987) and Barbari, Koros and Paul (1988). 

Figure 36 shows the temperature dependencies for different S BA ratios for a field of 2.0 x 10 V/cm. The results yield a between 0.069 and 0.103 eV, increasing with increasing dipole moment. The prefactor mobilities were approximately 1.5 x 10 2 cm /Vs, independent of the polymer. Values of the positional disorder parameter were approximately 2.4, also independent of the polymer. 

The prime cause of the surface shear viscosity is friction between surfactant molecules the cause of surface shear elasticity is attractive forces between those molecules, leading to a more or less continuous two-dimensional network. For a closely packed layer, the effects may be substantial. For layers of small-molecule surfactants, however, the values of rif are generally immeasurably small, about 10 5 N s m 1 or less. For adsorbed polymers, values between 10 3 and lN-m-s-1 have been reported. 

This table lists typical values of the dielectric constant (more properly called relative permittivity) of some important polymers. Values are given for frequencies of 1 kHz, 1 MHz, and 1 GHz in most cases the dielectric constant at frequencies below 1 kHz does not differ significantly from the value at 1 kHz. Since the dielectric constant of a polymeric material can vary with density, degree of crystallinity, and other details of a particular sample, the values given here should be regarded as only typical or average values. 

Polystyrene. Contact angles of the various pure liquids on polystyrene are given in Table II for surfaces of pure polystyrene prepared by solvent evaporation as well as by compression of the powdered polymer. Values of Q obtained in each case agree well with those... 

Poly(vinylidene Chloride) Copolymer. Contact angles observed on poly(vinylidene chloride) copolymer surfaces prepared by solvent evaporation are given in Table IV, along with the values obtained on highly polished surfaces of compressed disks of the additive-free powdered polymer. Values of 9 exhibited by the various liquids on each type of... 

Polymerization was carried out in 1,4-dioxane at 60 °C for 24 h. [Mjo = 0.25, mole ratio of monomer to catalyst = 50 °C. Methanol-insoluble polymer. Values were obtained by GPC analysis with polystyrene standards calibration. 

Van Krevelen [1] has presented an empirical relationship between relative values of the permeability of a polymer to various gases, which has been found to have reasonable accuracy for a broad range of polymers. Values are shown in Table 14.6. 

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