Browsing by Author "Lin, Ching-Mao"

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Conducting polymer blends prepared from polyaniline with n-dodecylbenzenesulfonic acid zinc salt as the secondary dopant
(2008-06-15)
Chao, Liang
;
Han, Yu-Kai
;
Hiseh, Bi-Zen
;
Huang, Ying-Jie
;
Hsieh, Tar-Hwa
A red-shift of the UV-vis spectra of n-dodecylbenzenesulfonic acid doped polyaniline (PANI (DBSA)(0.5)), resulting from the secondary doping of polyaniline backbones, was found in the presence of n-dodecylbenzenesulfonic acid zinc salt (Zn(DBS)(2)). It is proved to behave as steric hindrance spacers to induce the extension of the conjugation length through the straightening effect on the polyaniline backbones and the obtained mixtures (PANI(DBSA)(0.5) plus Zn(DBS)(2)) can be used as master batch materials (MB-13) for blending with regular polypropylene polymer (PP). The thermal degradation accompanied with loss of conductivity for MB-13 can be delayed to over 250 degrees C.when enough Zn(DBS)(2) was secondarily doped on PANI(DBSA)0.5., which allow the performance of its blending with other nonconducting/regular polymers possible. Below 80 rpm, increasing shear rates would induce higher viscosity difference between the MB-13 and PP matrix, resulting in elongation of MB-13 in the PP matrix and higher conductivities of the polyblends. The deviation from the Taylor equation, which is used to estimate the degree of elongation for a polyblend, started when shear rate is over 80 rpm. The leakage of Zn(DBS)(2) out of MB-13 can be confirmed by comparing the DSC thermograms and X-ray diffraction patterns with that of neat PP. Gradual deformation for the conductive fillers (MB-13) and a well-defined and expanded layered structure can be found when processing time is below 15 min with 60 rpm shear rate. The layers started to shrink back after 15 min of procession with the loss of the Zn(DBS)(2) from MB-13 in the PP matrix. (c) 2008 Wiley Periodicals, Inc.
Shearing effects on the conducting polymer blends
(2008-06-01)
Chao, Liang
;
Huang, Ying-Jie
;
Han, Yu-Kai
;
Tseng, Po-Hao
;
Hsieh, Tar-Hwa
To obtain a highly conductive polyblend based on doped polyaniline, an zinc salt based conductive master batch material (MB-13) made from mixing zinc n-dodecylbenzene sulfonate (Zn (DBS)(2)) and n-dodecylbenzene sulfonic acid (HDBSA) polyaniline (PANI(DBSA)(0.5)) together was compounded with PP in a melt-mixer varying the processing conditions. The SEM pictures show the morphologies of the polyblends were phase-separated into strips of elongated MB-13 for all samples. The elongation was first enhanced at shear rates ranged from 20 to 60 rpm. A shear rate of 60 rpm at 180 degrees C can elongate the conductive master batch phases (filler) to obtain both the highest aspect ratio and least resistance by keeping the secondary dopants of Zn (DBS)(2) stay within MB-13 from losing its conductivity and deformability.