Acid-sensitivity and physical properties of polymethylmethacrylate and polyurethane films containing polymeric styryl dye

Solution-cast films of polymethylmethacrylate (PMMA) and polyurethane (PU) containing polymeric styryl dye up to 5% by weight were prepared to investigate their acid-sensitivity and mechanical and thermal properties. Original red samples due to styryl dye turned out yellow very rapidly as they were exposed to acid vapor of hydrochloric acid or p-toluenesulfonic acid. According to UV/VIS spectroscopic measurements, characteristic peak intensities near 430 nm and 520 nm increased or decreased relatively with exposed amounts of acid, respectively. Both PMMA and PU samples showed uniform color distribution due to a good miscibility between polymer and dye which can be evidenced by measurements of glass transition temperature. No significant difference in acid-sensitivity was found between PU and PMMA except relative absorbance. However, dependence of their mechanical properties on dye content was somewhat different with PU or PMMA. In case of PMMA, modulus and breaking stress increased up to about 50% with increasing dye content, whereas those of PU samples showed only slight increase. It was ascribed to whether the matrix polymer was in the glassy or rubbery state.     

Syntheses and thermal properties of 5,10-disubstituted-2,3,7,8-tetracyano-5,10-dihydrodipyrazino[2,3-b:2′,3′-e]pyrazines and polymeric porphyrazines derived from 2,3-dichloro-5,6-dicyanopyrazine

Intermolecular cyclization of 2-alkylamino-3-chloro-5,6-dicyanopyrazine2 in the presence of tributylamine in N,N-dimethylformamide (DMF) gave 5,10-disubstituted-2,3,7,8-tetracyano-5,10-dihydrodipyrazino[2,3-b:2′,3′-e]pyrazines3, which showed strong mesomorphic property and were anticipated as new chromophoric system for functional dye materials. Absorption spectra, fluorescent properties and other physical properties were correlated with their chemical structures. Vanadyl oligomeric porphyrazine with long alkyl groups synthesized from3 had satisfactory solubility in tetrahydrofuran (THF), diethyl ether and dimethylsulfoxide (DMSO). The syntheses and characterization of vanadyl polymeric porphyrazines derived from3 with long alkyl groups are reported.     

Acid dyeing properties of meta-aramid fiber pretreated with PEO45-MeDMA derived from [2-(methacryloyloxy)ethyl] trimethylammonium chloride

A diblock copolymer (PEO₄₅-MeDMA) derived from [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MeDMA) was synthesized and applied to the dyeing of the meta-aramid fibers with some acid dyes. This copolymer created positive charges on meta-aramid fiber surface and a strong attraction with anionic groups of acid dyes. Meta-aramid fabric was pretreated using the synthesized copolymer and then dyed with two commercial acid dyes. The dyeability was found to be directly dependent on the concentration of PEO₄₅-MeDMA, pH in the dyebath as well as dye concentration. The color fastness of the copolymer pretreated dyed fabric was also evaluated.