Weighting, statistical

Table I indicates good agreement between the molecular weight distribution statistics obtained by coupled GPC/Viscometer method and the nominal values for t BS 706. The discrepancy between the Mark-Houwink parameters obtained here and the reported values for polystyrene standard ( ) in THF at 25°C (i.e., a = 0,706 and k = 1.60 x 10 ) may in part be due to the uncertainty involved in the determination of the dead volume between DRI and viscometer detectors. Our simulation studies over a range of dead volume values (0 to 120u)l) showed that a and k are quite sensitive to the dead volume between the detectors. Larger dead volume results in smaller o and larger k values. This is a direct result of a clockwise rotation of log [q] vs. log M(v) curve (Figure 12) which occurs when the dead volume correction is applied in quantitative analysis. The effect on the molecular weight statistics, however, appeared to...

Polyvinyl Chloride. The results obtained for a polyvinyl chloride sample are listed in Table 5. It is seen that the measured molecular weight statistics are in reasonable agreement with the nominal values. The Mark-Houwink parameters K and a obtained from the linear plot of log [nl vs. log M are in good agreement with one group of literature values (41-43) while the a value is lower than that of another group. (3,44-46)... 

Poly(meth)acrylamido Cationics. (Meth)acrylamido species are one of the most important commercial class of water-soluble monomers with wide-ranging applications. Cationic polyacrylamides are most often prepared by the normal free radical polymerization of the amine-containing monomer, and then most often in a copolymerization. For example, the protonated form of 9C and the monomer IOC are both readily copolymerized with 28C to yield high molecular weight statistical copolymers in which the molar composition is virtually identical to the feed composition (184,185). 

In addition to these signal processing features, some balances also provide useful convenience options such as conversion to nonmetric units, parts counting, weight statistics, percentage calculation, and animal weighing. 

This plot, the Lineweaver-Burk or double-reciprocal plot, gives a strong weighting to results at low substrate concentrations and should not be used without proper weighting statistics. Another form of the plot is... 

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