| Summary: | 博士 === 國立雲林科技大學 === 工程科技研究所博士班 === 92 === The purpose of this study is to carry out researches on the synthesis of the functional polyurethane copolymer (oligomer of amine terminated polyaniline ) and their polyblends, and to discuss the relationship between their thermal, physical, mechanical properties, conductivity, gas separation, compatibility, and their microcosmic structure. There are two steps for the synthesis of polyurethane copolymer. The first step is to prepare the polyurethane prepolymer by the reaction of polyol (containing polyester and polyether) with methylene bis(p-phenylisocyanate) (MDI) followed by the condensation polymerization with the suitable chain-extenders of 1,4 butanediol or aniline ended oligomer (OPA) .
The chemical structure and physical properties of the polyurethane copolymers and their blends have been characterized by Fourier transform infrared spectrometer (FTIR), solid-state nuclear magnetic resonance spectrometer (13C NMR), gel permeation chromatographyer (GPC) and element analysis (EA). The conductivity has been measured by a four-probe measurement. The gas permeability properties of copolymers have been measured by a permeation analyzer. Then, the properties about gas permeation flux (P), diffusivity (D), solubility (S) and selectivity ratio (a) were discussed. The compatibilities of polyurethane copolymers were investigated by FTIR, differential scanning calorimeter (DSC), dynamic mechanical analyzer (DMA) according to their characteristic adsorption peaks and glass transition temperatures (Tg's). The surface, cross section microstructure and the domain size were detected by scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscope (TEM), T1r(H), and T1(H). The mechanical properties were performed by a tensilon machine. The gas permeation, selectivity, and solubility were measured by gas chromatograph (GC) and BET methods. The diffusivity was estimated by the equation D=P/S from the solution-diffusion theory.
From the DSC and DMA thermal analysis, we know the soft-segment glass transition temperature (Tg's) rise with aniline ended oligomer in the aniline-urethane copolymer based on PBA1000 polyol (PUB1-OPAx), which demonstrates better miscibility between soft and hard segments. The depression of Tg's with PTMO1000 polyol (PUT1-OPAx) is due to the purification effect of the soft domain in PU. From the AFM photographs, we know that the surface mean roughness is raised with OPA content. The presence of two Tg's in DSC and DMA thermograms explain the existence of microphase separation between the copolymers. It agrees well with the photographs of TEM. The domain size obtained from T1r(H) and T1(H) data, shows that the TCH and T1r(H) of soft segment decrease with OPA; in other words, the mobility of soft segment in the aniline-urethane copolymer decreases with OPA. The soft-segment domain size of both PUB1-OPAx and PUT1-OPAx ranges from 4.2 to 60nm. The tensile strength of PUB1-OPAx and PUT1-OPAx are 31.45 and 22.61MPa, respectively. The conductivities measured by four-probe method are about 0.83 S/cm for neat OPA; 3.12´10-4 S/cm and 1.1´10-2 S/cm for PUB1-OPA30 and PUT1-OPA30, respectively when doped by hydrochloric acid.
The gas permeation analysis illustrates the permeability of the membranes decreased with OPA composition in the copolymer. The gas selectivity increased with OPA and the selectivities of CO2/CH4 were situated at about 250 for PUB1-OPA30 and 200 for PUT1-OPA30, respectively. The solubility of CO2 increased with OPA but the solubility of CH4 does not make any difference.
Two kinds of polyblends were studied. One of them concerned the blends of polyurethane and aniline-urethane copolymer (PU/PU-OPA) doped with different protonic acids for better mechanical properties and processability. The other is the blend of aniline end oligomer and aniline-urethane copolymer (OPA/PU-OPA) for raising the content of amine group to improve its selectivity for CO2/CH4 separation.
Blends of polyurethane and aniline-urethane copolymer (PU/PU-OPA ) doped with different protonic acids, including of camphorsulfonic acid (CSA) and dodecylbenzenesulfonic acid (DBSA), were prepared and studied. According to DMA and DSC results, the blends show a partial compatibility and have a purified effect between the individual components of the blends. The blends using CSA as a dopant resulted in better heat resistant, tensile strength but poor electronic conductivity than that of DBSA doped one.
Blends of aniline ended oligomer and aniline-urethane copolymer (OPA/PUT1-OPA30) prepared for better permeation were also studied. According to their tensile strength, TEM photographs, the blends show a partial compatibility in low OPA content and a serious phase separation in high OPA content. Tensile strength is higher in low OPA and lower in high OPA. The permeability for the blend is better than that of copolymer but the selectivity of CO2/CH4 for the blend was not improved.
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