Weight glasses

Low-density Medium-density High-density Ultra high-molecular-weight Glass-fiber- reinforced, high-density Ethylene-vinyl acetate copolymer... 

Solution Polymers. Acryflc solution polymers are usually characterized by their composition, solids content, viscosity, molecular weight, glass-transition temperature, and solvent. The compositions of acryflc polymers are most readily determined by physicochemical methods such as spectroscopy, pyrolytic gas—liquid chromatography, and refractive index measurements (97,158). The solids content of acryflc polymers is determined by dilution followed by solvent evaporation to constant weight. Viscosities are most conveniently determined with a Brookfield viscometer, molecular weight by intrinsic viscosity (158), and glass-transition temperature by calorimetry. 

An instrument to measure the specific gravity (SG) of fluids. Typically a small, calibrated, and bottom-weighted glass or metal cylinder that floats to a level indicating the SG. 

The molecular weight, glass transition temperature (Tg) and size of dispersed polymer particles in the latexes can... 

Fig. 5.11. Vacuum reactor for chlorination of metals. A Reaction vessel (100 ml) B beryllia crucible containing titanium metal C silica cradle D crucible support also serving as evacuation duct, and finally sealed off at the top at E F capillary tube G duct for breaker H appendix containing liquid chlorine J fragile capillary tip K weighted glass breaker L glass-coated magnetic retainer.

Fig. 7. The effect of filler particle shape on the viscosity of polypropylene (PP) at 200 °C (A) neat PP ( ) PP containing 40% by weight glass beads (O) PP containing 40% by weight talc. (Filler size distributions similar, at 44 pm or less) [17]...

Polymerization. Poly (methyl methacrylate) was obtained commercially. The polymers of other methacrylates and their copolymers were prepared in toluene with 2,2 -azobisisobutyronitrile (AIBN) at 60 °C. All the polymers prepared free radically were syndiotactic or atactic. Isotactic poly(a,a-dimethylbenzyl methacrylate) was obtained using C6H5MgBr as the initiator in toluene at 0°C. Poly(methacrylic acid) was prepared in water using potassium persulfate at as the initiator 60 °C. The molecular weights, glass transition temperatures and tacticities of the polymethacrylates are summarized in Table I. 

Figures 2-5 depict the effects of CL content upon number-average molecular weight, glass transition temperature(Tg) and crystallization characteristics for those copolyesters derived from oligomeric PCL-diols.

Polystyrene, 20% by weight glass, 32% for fabric laminate, epoxy silane compression molded at 500°F. 

The molecular weight, glass transition temperature (T) and size of dispersed polymer particles in the latexes can affect the strength and c loride ion permeability of latex-modified mortar and concrete to a certain extent [87,93] (Tables 6.11 and 6.12). SBR latexes with smaller particle size appear to initially provide lower chloride ion permeability to the mortars, but a difference in the permeability between the smaller and larger particle sizes eventually becomes insignificant as the concrete ages. The initial decrease in the permeability observed with smaller particles is attributed to the fact that smaller particle size coalesce into films faster than the larger particle sizes. 

In transient shear flows starting from an isotropic distribution of fiber orientations, considerably higher viscosities will be initially observed, until the fibers become oriented. In Bibbo s experiments, t]r for isotropically oriented fibers is around 3.5 for v = 75. These viscosities can also be predicted reasonably well by semidilute theory and by simulations (Mackaplow and Shaqfeh 1996). Figure 6-25 shows the shear stress as a function of strain for a polyamide 6 melt with 30% by weight glass fibers of various aspect ratios, where the fibers were initially oriented in the flow-gradient direction. Notice the occurrence of a stress overshoot (presumably due to polymer viscoelasticity), followed by a decrease in viscosity, as the fibers are reoriented into the flow direction. 

Figure 6.25 Shear stress as a function of shear strain for a polyamide 6 filled with 30% by weight glass fibers of different aspect ratios, where the fibers were initially oriented in the velocity-gradient direction. The shear was interrupted after about 7 strain units, and the stress was allowed to relax. The shecir was then restarted the shear stress quickly returned to the value it had before cessation of shearing, showing that fiber orientation only changes during shearing. (From Laun 1984b, reprinted with permission from Steinkopff Publishers.)...

Hensel Bielowka, S., Psurek, T., Ziolo, J., and Paluch, M. (2001) Test of the fractional Debye-Stokes-Einstein eqnation in low-molecnlar-weight glass-forming liqnids nnder condition of high compression, Phys. Rev. E 63, 062301 Wang, C. H. (2002) Enhancement of translational diffusion coefficient of a probe in a rotationally anisotropic fluid, Phys. Rev. E 66, 021201... 

This equation is obeyed for some radical combinations in low molecular weight glasses but is rather unsatisfactory for the combination of radicals in polyethylene [217]. 

A hydrometer, a weighted glass bulb inserted in a liquid, may be used to determine specific gravity. The higher it floats in the liquid, the more dense the liquid. A hydrometer that is calibrated to indicate the specific gravity of urine is called a urinometer. 

Figure 3.82 Flexural creep behavior of 25% by weight glass-filled ETFE as a function of stress, time, and temperature...

Filled ETFE (containing 25% weight glass fiber)... 

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