Intermediate molecular weight

Amide interchange reactions of the type represented by reaction 3 in Table 5.4 are known to occur more slowly than direct amidation nevertheless, reactions between high and low molecular weight polyamides result in a polymer of intermediate molecular weight. The polymer is initially a block copolymer of the two starting materials, but randomization is eventually produced. 

Addition cure silicones can be delivered from solvent, waterborne emulsions, or 100% solids systems. The solvent free versions employ base polymers of intermediate molecular weight to achieve processable viscosity. These base polymers can have reactive moieties in terminal and/or pendant positions. These lower molecular weight, more functional systems result in a tighter crosslink network which feels rubbery to the hand. Low amounts of high molecular weight additives are included in some formulations to provide a more slippery feel [51,52]. 

A novel feature of the route is that it leads to monomeric and oligomeric alkyl silicates from metal silicates in good yield and with full or substantial siloxane framework preservation. Further, it leads to oligomeric organosiloxanes of intermediate molecular weight from alkyl silicates in good yield and with siloxane framework preservation. 

Atmospheric Pressure Chemical Ionization (APCI)/MS APCI/MS is used to analyze compounds of intermediate molecular weight (100-1,500 da) and intermediate polarity and is particularly useful for the analysis of biochemicals such as triacylglycerides, carotenoids, and lipids (Byrdwell, 2001). For volatile, nonpolar compounds of low molecular weight, GC/MS is preferred to APCl/MS whereas APl-electrospray/ MS provides better results for larger, more polar materials. The selection of APCl/MS over GC/MS or APl-electrospray/MS depends on the compounds to be analyzed. Many LC/MS instruments can be easily switched between APCl/MS and APl-electrospray/MS so that it can be rapidly determined which ionization process is more suitable to a given chemical. Additional manipulations such as pre and postcolumn derivatization reactions (Nagy et al., 2004 Peters et al., 2004) or coulometric oxidation (Diehl et al., 2001) can make the chemicals of interest more amenable to detection by APCI. 

Neurotransmitters are generally of low molecular weight (200 or below) whereas peptides are of intermediate molecular weight (1000 to 10000 or occasionally more). 

G.D.J. Phillies, D. Rostcheck, and S. Ahmed Probe Diffusion in Intermediate Molecular Weight Polyelectrolytes Temperature Dependence. Macromolecules 25, 3689 (1992). 

An important reason for the lack of intermediate molecular weight products has been the unavailability of low cost paraffins with molecular structures suitable for these materials. Synthetic paraffins, prepared by the Fischer-Tropsch process and often known as Kogasin, have been available in this intermediate molecular weight range (10) and have been used in Europe to make chloroparaffins (9). However, these materials also are not completely satisfactory because of a combination of cost, purity, and molecular structure. 

An indication of the validity of the extrapolation method could be given by light-scattering analysis of an intermediate-molecular-weight hydrolysate due to a very low cellulase activity. Indeed, at a relatively high HEC concentration of 3.152 X 10 3 g/mL, a limo-o Kc/Re value of... 

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