Polyethers property-structure relationships

In most cases, a suitable molecular modification of the catalyst structure is required to obtain the desired thermoresponsive properties. Polyether and in particular PEG substituents are receiving considerable interest in this field. The present study has addressed structure-activity relationships for well-defined low molecular weight model ligands in the rhodiiun-catalyzed hydroformylation of 1-octene as benchmark reaction. Figure 3 summarizes the observed trends. 

Part I of this series explored the structure-property relationships of tetramethylene terephthalate/polyether terephthalate copolymers as a function of variations in the chemical structure, molecular weight, and concentration of the polyether units (10). Of the polyether monomers tested, poly (tetramethylene ether) glycol of molecular weight approximately 1000 was found to provide copolymers having the best overall combination of physical properties and ease of synthesis. 

In 2004, Fan and coworkers synthesized a series of chiral dendrimer hgands bearing a chiral diphosphine Pyrphos at the focal point of the Frechet-type polyether dendrons (Figure 4.6) [43]. The relationship between the primary structure of the dendrimer and its catalytic properties was established in the Rh-catalyzed hydrogenation of a-acetamidocinnamic acid (Scheme 4.5). High enantioselectivi-... 

An alternate approach to increase compliance of urethane block copolymers is to vary the structure of the soft polyether block to lower the initial modulus. In our analysis of structure-property relationship of the block copolyurethanes, it would appear that a polyether segment based on a... 

Green CD, Vaughan AS, Mitchell GR, Liu T (2008) Structure property relationships in polyeth-ylene/montmorillonite nanodielectrics. IEEE Trans Diel Electr Insul 15 134—143... 

Wolfe J R Jr (1977) Elastomeric polyether-ester block copolymers. I. Structure-property relationships of tetramethylene terephthalate/polyether terephthalate copolymers. Rubber Chem Technol 50 688-703. 

Mody P C, Wilkes G L and Wagener K B (1981) Structure-property relationships of a new series of segmented polyether-polyester copolymers, J Appl Polym Sci 26 2853-2878. 

Recently, the preparation of two series of PTE of a new type with acid or ionic groups in the polyether SS and the investigation of their stucture-property relationships have been reported [49,65-69]. The first series was based on PTMG (M series) and the second on PEG (E series). The main interest was focused on understanding the influence of structure and morphology on the mechanisms of molecular mobility and ionic conductivity, as well as the relation between segmental mobility and ionic conductivity. For structural and morphological studies, DSC, WAXS, SAXS and Fourier transform infrared photoacoustic spectroscopy (FTIR PAS) were employed. The molecular dynamics and ionic conductivity were studied by DRS and TSDC. 

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