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Melting temperature, gel

Agar, which is low in metabolizable or inhibitory substances, debris, and thermoduric spores, is ideal for the propagation and pure culture of yeasts, molds, and bacteria. Agar also meets the other requirements of ready solubiUty, good gel firmness and clarity, and a gelation temperature of 35—40°C and a gel melting temperature of 75—85°C. A clarified and purified form of the bacterial polysaccharide, geUan gum, is the only known satisfactory substitute. [Pg.431]

The formation of a photo-reversible gel is explained as foUows. The azobenzene groups in the surface region of the polymer coil help the coil overlap. When they change to a more polar cis form, the interactions are strengthened. The change in the interpolymer interactions is responsible for the change in the gel melting temperature. [Pg.64]

Hot (100 C) 97% sulfuric acid is a good solvent for poly(p-phenylenebenzobisthiazole) (PBT) (Figure 13.5). A drastical drop in the solvent power is achieved by a decrease in temperature which causes thermoreversible gelation of the system [47]. The formation of a porous structure from a uniform, homogeneous, isotropic solution has been observed. Indications were found that the gel melting temperature increases with concentration and molecular weight of PBT. [Pg.438]

Fig-53. ln(Cp,Pb) of PVA/borate gels of various compositions plotted vs reciprocal gel melting temperature, calculated from data presented by Shibayama et aL [193]... [Pg.53]

Although the solvent plays an important role, in many cases the stereoregularity of the s-PMMA is the limiting factoi in general the gel melting temperature... [Pg.63]

F. 99. Logarithm of the critical gel (xmcentration plotted vs reciprocal gel melting temperature of aoylo-nitrile-vinyl acetate (7.7 wt%) copolynKrs dissdved in various solvents (A) ethylene carbonate, (A) y-butyrolactone, (O) IVJV-dimethylfor-mamide, ( ) dim yl sulfoxide, ( ) N,iV-diniethylacetamide (constructed after data presented in [301])... [Pg.99]

Fig. 109. Reciprocal gel-melting temperature vs logvi (V2 - polymer volume fraction) for low density polyethy-lenes of various long brandies content (O), (A) and 7.18, 4.07, and 0 branch points of long branches per polymer molecule, respectively. Reproduced from Polym J [Rdt 19] by the courtesy of die authors and The Sodtty of Polymer Sdence, Japan... Fig. 109. Reciprocal gel-melting temperature vs logvi (V2 - polymer volume fraction) for low density polyethy-lenes of various long brandies content (O), (A) and 7.18, 4.07, and 0 branch points of long branches per polymer molecule, respectively. Reproduced from Polym J [Rdt 19] by the courtesy of die authors and The Sodtty of Polymer Sdence, Japan...
Another equation from which the Eldridge-Ferry method starts is the relation between the molecular weight M of a polymer and the gel melting temperature. It is given by... [Pg.248]

Figure 8.2 shows the result of our modified Eldridge-Ferry plot for the gel melting concentration. The gel melting temperature Tm is estimated from the temperature at which the DSC heating curve shows an endotherm peak. The slope of the solid lines with... [Pg.249]

Ball drop A steel ball with a known diameter or weight is placed on the gel and the gel warmed at a certain heating rate. The ball drops at the gel melting temperature. [Pg.2241]


See other pages where Melting temperature, gel is mentioned: [Pg.269]    [Pg.158]    [Pg.22]    [Pg.63]    [Pg.94]    [Pg.210]    [Pg.16]    [Pg.16]    [Pg.84]    [Pg.22]    [Pg.20]    [Pg.78]    [Pg.83]    [Pg.94]    [Pg.99]    [Pg.104]    [Pg.107]    [Pg.243]    [Pg.253]    [Pg.264]    [Pg.293]    [Pg.35]    [Pg.78]    [Pg.85]    [Pg.99]    [Pg.118]    [Pg.124]    [Pg.270]    [Pg.212]    [Pg.243]    [Pg.172]    [Pg.63]    [Pg.289]    [Pg.120]   
See also in sourсe #XX -- [ Pg.120 , Pg.121 , Pg.125 , Pg.127 ]




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