LALLS

Hill, J. W. (1999). Gcrrcral Chemistry. Upper Saddle River, NJ Prcnticc-1 lall. 

Alexander, D. E., and Fairbiidge, R. W., eds. (1999). The Chapman I lall Encyclopedia of Environmental Science. Boston, MA Kluwer Academic. 

Weidenbaum, M. L. (1995). Business and Government in the Global Marketplace. Englewood Cliffs, NJ Prciiticc-I lall, Inc. 

Buell, P., and Girard, J. (1994). Chemistry An Environmental Perspective. Englewood Cliffs, NJ Prentice-I lall. 

Table 3. Molecular Weights of the Same Poly (P-PIN) Samples obtained by GPC and LALLS...

LALLES J p, DREAU D, HUET A, TOULLEC R (1995) Systemic and local gut-specific antibody responses in preruminant calves sensitive to soya. Res Vet Sci. 59 56-60. 

A number of the limitations of conventional SEC can be overcome through use of a low angle laser light scattering (LALLS) detector attached in series with a concentration... 

The hydrodynamic volume separation mechanism of SEC, along with the different molecular size/weight relationships of branched and linear polymers of identical chemical composition, can be exploited with the SEC/LALLS method to gain information about polymer branching. In the studies described in this paper both conventional SEC and SEC/LALLS are used to obtain data about branching in samples of poly(vinyl acetate) (PVA) and polychloro-prene (PCP). 

The following work demonstrates the use of SEC/LALLS to study the variation of g with molecular weight for broad MkD materials. This approach gives a qualitative indication of polymer branching. 

Refractometry (dn/dc) the LALLS Optical Solutions of f VA and PCP with known concen-... 

A separate program was developed on tfie LDS-2 to correct the SEC/LALLS Rj, for band-spreading (Appendix). 

A universal calibration relation for the SEC/LALLS system was derived by fitting the seven J, Vr data pairs with a linear equation... 

Sample masses of 8.90 x 10" gm and 1.05 x lO"" gm were chromatographed for PVA 0107-066 and PVA 0106,respectively,while 1.47 X lO"" gm of PCP was injected. An estimated A2 value of 5x10" mol-cmvgm was used to process the PVA and PCP data with MOLWT. In view of the relatively small magnitude of the term containing A2 in the SEC/LALLS equations ( ), uncertainty in R from this approximation is insignificant. 

Table I shows molecular weight data obtained from SEC/LALLS measurements on the narrow MWD polystyrene standards. Bandspreading correction of the ft values generally resulted in a decrease in fl of 1% to 4% Below the value directly obtained from treatment 8f SEC/LALLS data with the MOLWT program.

Data from the SEC/LALLS Analysis of Narrow MWD Polystyrene... 

Data V(ml) Table II from SEC/LALLS and conventional SEC analysis of NBS SRM706 polystyrene /M (MJvXlO" (M )vX10-5 g ... 

Data from SEC/LALLS and conventional SEC analysis of two PVA Samples... 

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