Dihydroxybenzoic polymers

The most commonly used matrices for synthetic polymers are DHB (2,5-dihydroxybenzoic acid), HABA (2,(-4-hydroxyphenylazo)benzoic acid), lAA (3-j3-indoleacrylc acid), dithranol (1,8,9-trihydroxyanthracene), sinapinic acid (3,5-dimethoxy-4-hydroxy cinnamic acid), all trans-retinoic acid, and 5-chlorosalicylic acid. Exhaustive lists of useful matrices are available in the literature. ... 

Matrix-assisted iaser desorption/ionization (MALDI). This is another ionization method for the analysis of large molecules such as peptides, proteins, and nucleic acids, as well as some synthetic polymers. In MALDI, the analyte is first cocrystallized with an excess of a matrix, e.g., sinapinic acid or dihydroxybenzoic acid, that has a constituent aromatic component able to absorb photons from a UV laser beam. When the dried analyte matrix mixture is exposed (inside the vacuum chamber) to a sudden input of energy from a laser pulse the matrix evaporates, essentially instantaneously, carrying with it the analyte molecules. The matrix forms reagent ions that protonate the analytes. The selection of the matrix is critical as different compound classes exhibit substantial, matrix-dependent differences in ionization efficiency. The MALDI matrix should not be confused with the alternative use of the term matrix that is used to denote the medium in which biological and/or environmental components are presented, e.g., blood plasma, urine, sediment. 

Polyether-b-polyester dendrimer 3,5-dihydroxybenzyl alcohol as monomer for ether-linked fragments and 2,2,2-trichloroethyl 3,5-dihydroxybenzoate for ester linked fragments radially alternating the dendritic segments produced segmented-block polymer and concentric alternation gave layer-block polymer spectroscopy, thermal characterization described. [269]... 

The hyperbranched polymer may contain 3,5-dihydroxybenzoic acid derivatives as the monomer. For example, h5rperbranched polyethylene glycols can be produced by heating methyl 3,5-bis-((8 -hydroxy-3, 6 -dioxaoctyl)oxy)benzoate. This is a hydrolyzate of methyl 3,5-bis((8 -(terf-butyldiphenylsiloxy)-3, 6 -dioxaoctyl)oxy)-benzoate produced from l-bromo-8-(ferf-butyldiphenylsiloxy)-3,6-dioxaoctane and methyl-3,5-dihydroxybenzoate, with dibutyltin diacetate in a nitrogen atmosphere, cf.. Figure 3.21. Thus, a hyperbranched polymer, poly[bis(triethylene glycol)benzoate], is synthesized. 

Dendrimers can also reduce the crystallinity of PEO. There are various kinds of dendrimers. When rigid 3 -dihydroxybenzoic acid is introduced as a branch unit, the ionic conductivity of the formed PEO dendrimer at room temperature (which is 1(P S/cm) is not much increased. The ionic conductivity is also related to the chain terminal groups for example, the ionic conductivity of a polymer with ether termini is higher than that with acetyl termini. Dendrimers can also be blended with PEO to increase its ionic conductivity. A cross-linked polymer with a dendrimer structure (such as Figure 10.22) can also have a good conductivity, in this case 10 S/cm at room temperature. 

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