PEDA

PFPA, PFBS, PFOA, l,p-PFNA, PENA, PEGS, PEDA, L-PEDS Edible Fish 0.23-23.04 ng/g fw [73]... 

PEGS, PEHxS, PEDoDA, PEUnDA, PEDA, PENA, PEOA Farm, pet animals PEGS 67 ng/g (Chicken), 54 ng/g (pigs), 34 ng/g (cattle) [72]... 

Pentaervthrltol Diacetonide (PEDA). Pentaerythrltol, 27 g (0.2 mol), and acetone, 75 g, were heated overnight with 1 g of Rohm and Haas XN-1010 strong acid Ion exchange resin In a Soxhiet extraction apparatus containing 3A zeolite. The mixture was diluted with additional acetone and unreacted pentaerythrltol was filtered off. The solution was concentrated under reduced pressure and the product was partitioned between water and ether. 

Fig. 8 Immobilizing of streptavidin or biotin on mercaptotrimoxysilane-activated glass surfaces, a SAM of PEDA is created on a silicon surface and a mask is used to direct 193 nm light to attach PEDA at specific locations. A SMPB layer is attached to the remaining PEDA layer and thiolated oligonucleotides attached to the penultamine sulhydryl groups...

We have used X-ray methods to compare the crystallite size of RIM specimens prepared with and without use of a polyether diamine (PEDA) additive. These results are compared with differential scanning calorimetry data on the hard domain melting behavior and dynamic-mechanical studies of the extent of phase separation. Mechanical data on flexural modulus, elongation, impact strength, and heat sag behavior have been obtained for the same specimens and have been correlated with the structural analyses. 

Figure 4 and 5 and Table III show the DSC data for these RIM specimens. It is seen that AH for the hard segment melting In the unannealed/wlthout PEDA specimens increases on annealing (for both the 18 Eg and 30 Eg series) and essentially the same Increase occurs in the unannealed/with PEDA specimens. These effects corrleate with the X-ray data showing a similar increase in the crystalline perfection of the hard domains with annealing or with the use of PEDA. 

EG Series No Diamine Unannealed No Diamine Annealed PEDA Unnanealed PEDA Annealed... 

The dynamic mechanical data (Figure 6) point to enhanced phase separation as a result of annealing, as shown by the flatter storage modulus curves. The data show that a similar Improvement Is obtained by annealing without PEDA and by addition of PEDA without annealing. A similar conclusion Is also derived from the heat sag data. 

Thus the structural and mechanical data are mutually compatible and point to an Increase In the order of the hard domains as a result of use of the PEDA additive, comparable to that which Is achieved by annealing without use of the additive. At present we can only speculate on the mechanism whereby the PEDA leads to the higher order. The crystalline reflections are those of homopoly (MDI/EG) and hence the PEDA chains must be outside the crystalline regions, but the flexural modulus does Increase Indicating some hard domain association. Nevertheless, the PEDA could be Intimately Involved with the hard domains. The amine groups are much more reatlve than the hydroxyls of the chain extender and polyol, and hence the first chemical reaction will Involve PEDA and MDI. The MDI-PEDA-MDI units may serve as nucleatlon agents for the formation of the hard domains, perhaps because of their low solubility In the reaction mixture. 

Schoeman, H., Vivier, M., du Toit, M, Dicks, L.M.T., and Pretorius, I.S. 1999. The development of bactericidal yeast strains by expressing the Pediococcus acidilactici pediocin gene (pedA) in Saccharomyces cerevisiae. Yeast 15, 647-656. 

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