Novel poly(aryl ether quinoxaline)s (PEQs) were prepared via a two-step procedure. First, poly (ether benzil) (PEB) was synthesized by the polycondensation of 4,4’-difluorobenzil and 4,4’-isopropylidenediphenol.Then, PEB was reacted with 1,2-diaminobenzene and 4,4'-oxydibenzene-1,2-diamine to give the PEQs. The molecular weight of the PEQs could be adjusted easily by varying the molar ratio of 1,2-diaminobenzene to 4,4'-oxydibenzene-1,2-diamine. The PEQs exhibited good solubility in common organic solvents such as NMP, DMAc, DMF, cyclohexanone and chloroform. In addition, the PEQs also had high glass transition (Tg) temperatures and good thermal properties, with an initial thermal decomposition temperature above 475 oC and glass transition temperatures above 210 oC. They also exhibited excellent resistance to strong acid and alkali.
With 2,2',5',2''-Terthiophene as starting material, two liquid crystalline compounds containing Schiff’s base unit were synthesized in this paper. The structure of the compounds was confirmed by FTIR and 1H NMR. The thermally induced phase transition behaviors were investigated by POM and DSC, and the temperature ranges of liquid crystal phase of the two compounds were compared. Results showed that the symmetric compound exhibited a lower clearing point temperature and broader temperature range of liquid crystal phase.
A reversible addition fragmentation chain transfer (RAFT) agent, 2- (dodecylthiocarbonothioylthio)propanoic acid (RAFT-1), was synthesized and characterized. Equimolar doses of acrylic acid (AA) and n-butyl acrylate were successively polymerized in the presence of RAFT-1 to give an amphiphilic macro RAFT agent (RAFT-2), which had a calculated average degree of polymerization of ten. Core-shell poly (butyl acrylate-co-diacetoneacrylamide) latex was prepared by using RAFT-2 as a reactive surfactant. The latex was narrowly distributed and very stable, which had a solid concentration as high as 45 wt.% and an average diameter of about 50 nm, Latex films were prepared with the core-shell emulsion and small amount of cross-linking agent, adipic dihydrazide. Results showed that cross-linking reaction occurred with the evaporation of water. The resulting cross-linked latex film was tough and transparent.
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