Browsing by Author "Han, Yu-Kai"

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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.
Degradation induced variation of LC transition of poly(n-undecyl isocyanate)
(2008-05-01)
Hsieh, Bi-Zen
;
Chuang, Hung-Yi
;
Chao, Liang
;
Huang, Ying-Jie
;
Tseng, Po-Hao
The first-order thermal transitions including side-chain melting, crystal-LC, biphasic chimney-like, and isotropic transitions of poly(n-undecyl isocyanate) (PUDIC) were investigated by varying its thermal history. After annealing at 140 degrees C for different periods of time, it leads to different degrees of backbiting degradation into n-undecyl isocyanurate trimer which behaves as a solvent for the rest non-degraded/rigid PUDIC to change into a lyotropic LC from thermotropic transition. Based on the degree of degradation, various amounts of trimers are present and the PUDIC demonstrates different types of thermal transitions found in DSC thermograms due to the variation of the non-degraded PUDIC concentration in solvent trimers. Finally, a phase diagram includes all types of crystallines, LC, and isotropic regions can be drawn according to the DSC thermograms. (C) 2008 Elsevier Ltd. All rights reserved.
Formation and degradation mechanism of a novel nanofibrous polyaniline
(2009-06-01)
Ho, Ko-Shan
;
Han, Yu-Kai
;
Tuan, Yu-Tsung
;
Huang, Ying-Jie
;
Wang, Yen-Zen
A nanotubular, nanofibrous polyaniline (PANINT) was prepared from an emulsion polymerization in the presence of n-dodecylbenzene sulfonic (DBSA) and hydrochloric acids. The building of the tubular structure based on the tubular micelles from the accumulation (pile up) of micelles at high surfactant concentration, leading to early stage of centipede-like and eventual tubular morphologies. The PANINT molecule owning a highly conjugated backbone demonstrated a free carrier-tail in the near-IR region due to its helical conformation. After dedoping, the once empty PANINT with only some complexed DBSA inside shrank into solid rods, after the removal of the complexed DBSA. As a result, the solid rods were filled with helical emeradine base (nano-EB) molecules associated with inter-molecular H-bonding. The solid rods of nano-EB went on crosslinking and carbonization after 200-300 degrees C by opening the quinoid rings and the inter-molecular H-bondings were destroyed with nano-EB molecules crosslinking into ladder-like structure. When temperature was over 300 degrees C and below 800 degrees C, carbonization enhanced by de-ammoniaization, causing a significant weight loss. However, the cleavage of aromatic rings into aliphatic pieces occurred after 800 degrees C, which chopped the ladder-like, strips of carbonized nano-EB sheets into small pieces of nano-particles. The conductivity of the pyrolyzed nano-EB was found to be around 10(-5) s/cm, 10,000 times higher than the neat nano-EB of 10(-9) s/cm due to the carbonization. (C) 2009 Elsevier B.V. All rights reserved.
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.
Synthesis and Characterization of Poly(n-undecyl isocyanate)/Polyaniline Polyblend
(2010-07-05)
Li, Yu-Jen
;
Ho, Ko-Shan
;
Lo, Wan-Ting
;
Yang, Shin-Shiao
;
Chao, Liang
Poly(n-undecyl isocyanate) (PUDIC)/n-dodecylbenzenesulfonic acid (DBSA)-doped polyaniline (PANIDBSA) polyblend was prepared and the effect of the H-bonding between these two polymers on the compatibility, conjugation chain length of PANIDBSA, and helixity of PUDIC in the polyblend system were studied. The monomer and polymer were characterized by NMR spectra and the polyblend was analyzed by FTIR, UV-vis spectra, and wide-angle X-ray diffraction. It was found when the blend composition of the PUDIC was higher than 10%, the WAXD patterns demonstrated lower angle shifting for the peaks at around 2 theta = 2-2.5 degrees, referring to the distance between the layers of the layered structure of PANIDBSA crystalline with increasing PUDIC, indicating the expansion of the layered structure of PANIDBSA. The FTIR spectra illustrated the presence of an absorption peak at 1700 cm(-1) shift to higher wave number with PUDIC due to its H-bonding with PANIDBSA. The UV-vis spectra of PANIDBSA described a blue-shift of the lambda(max) with PUDIC, indicating that the presence of PUDIC in the polyblend system can interrupt and decrease the conjugation chain length of PANIDBSA. The optical activity of the helical PUDIC decreased notably with the presence of PANIDBSA, resulting from the reversed helical effect (de-nature) of H-bonding. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 1-7, 2010