Influence of liquid crystalline polymer and recycled PET as minor blending components on rheological behavior,morphology, and thermal properties of thermoplastic blends

In this study, the potential of recycled poly(ethylene terepthalate) (rPET) as a well‐defined reinforcing material for the in situ microfibrillar‐reinforced composite (iMFC) was investigated in comparison with that of liquid crystalline polymer (LCP). Each dispersed phase (LCP or rPET) was melt blended with high density polyethylene (PE) by using extrusion process. The rheological behavior, morphology, and the thermal stability of LCP/PE and rPET/PE blends containing various dispersed phase contents were investigated. All blends and LCP exhibited shear thinning behavior, whereas Newtonian fluid behavior was observed for rPET. The incorporation of LCP or rPET into PE significantly improved the processability. A potential of rPET as a processing lubricant by bringing down the melt viscosity of the blend system was as good as LCP. The elongated LCP domains were clearly observed in as‐extruded strand. Although the viscosity ratio of the rPET/PE system was lower than that of the LCP/PE blend system, most rPET domains appeared as small droplets. An addition of LCP and rPET into the PE matrix improved the thermal resistance significantly in air but not in nitrogen. The obtained results suggested the high potential of rPET as a processing aid and good thermally resistant material similar to LCP. Copyright © 2009 John Wiley & Sons, Ltd.     

Thermal degradation behaviors of polybenzoxazine and silicon-containing polyimide blends

Thermal behaviors of polymer blends between common-type polybenzoxazine (PBA-a) and polysiloxane-block-polyimide (SPI) were studied using Dynamic Mechanical Analysis (DMA) and Thermogravimetric Analysis (TGA). The polymer blends showed only one glass-transition temperature (T_g) that increased as the content of SPI increased. Synergistic behavior in the char formation of the alloys was clearly observed. The DTG curves showed three stages and two stages of decomposition reaction in neat PBA-a and SPI, respectively. For the blending systems with 25 wt%, 50 wt%, and 75 wt% of SPI, the DTG thermograms of the blends exhibited four stages of thermal decomposition reaction. The apparent activation energies (E_a) of each step were determined using Kissinger method, Flynn-Wall-Ozawa method and Coats-Redfern method. The type of solid state mechanism was determined by Criado method. From the calculation, the solid state thermal degradation mechanism is proposed to be F1 (random nucleation with one nucleus on the individual particle) type for PBA-a, SPI, and their blends.     

Synergistic effect of solvent and solid additives on morphology optimization for high-performance organic solar cells

Science China Chemistry - Controlling the photoactive layer morphology towards nanoscale bi-continuous donor/acceptor interpenetrating networks is a key issue to build high-performance organic...     

Analysis and Improvement of Reflection-type Transverse Modulation Optical Voltage Sensors

Reflection-type transverse modulation optical voltage sensors, which employ reflection retarders to replace quarter-wave plates, are convenient for practical use. In previous literatures, the measured voltage was all applied to Bi4Ge3O12 crystal along the (110) direction for transverse modulation optical voltage sensor, and crystals are used as sensing materials. In this paper, reflection-type transverse modulation optical voltage sensor has been analyzed theoretically and a novel configuration in which the measured voltage is applied to a Bi4C-e3O12 crystal along the (001) direction with light wave passing through the crystal in the (110) direction has been proposed. According to this theoretical analysis, a novel optical voltage sensor, which can be used in a 220 kV optical fiber voltage transformer, has been designed and assembled. Experimental results showed that the linearity and the stability of the sensor during 24 hours can reach 0.3％.     

Large-scale quantification of aluminum in AlxGa1-xN alloys by ToF-SIMS: The benefit of secondary cluster ions

Precise determination of composition is requisite for Al_xGa_1-xN-based energy band engineering. Secondary cluster ions in a time-of-flight secondary ion mass spectrometry (ToF-SIMS) full spectrum are introduced for accurate quantification of Al in Al_xGa_1-xN for AlGaN-based devices. It was found that statistical analysis with huge number of large secondary cluster ions (without small ions) show much better linear dependence with apparent compensation of matrix effect, particularly in negative polarity. For Al_xGa_1-xN with x = 0 to 0.7, x values calculated based on large negative cluster ions (NCIs) show excellent linear dependence with real values. Besides, atomic count ratio of C (Al)/C (Ga) and C (Ga)/C (Al) also shows great linear relationships with corresponding mole fraction ratios in a large range. Overlap of these linear ranges offers a reliable and convenient quantification protocol of Al_xGa_1-xN covering a full range of x = 0 to 1. This study verifies that the secondary cluster ions are beneficial for quantification of Al_xGa_1-xN-based materials.     

Morphology Optimization of the Photoactive Layer through Crystallinity and Miscibility Regulation for High-performance Polymer Solar Cells

On the premise of strongly crystalline materials involved, it is a challenge to control the phase separation of bulk-heterojunction donor/acceptor active layer to fabricate high-performance polymer solar cells (PSCs). Herein, we develop a molecular design strategy of the third component to synthesize three guest materials (namely BTPT, BTP-Th, and BTP-2Th) to address this issue. We investigate and reveal the effect of crystallinity and miscibility of the third component in controlling the phase separation of Y6-derivatives-based blend film. As a result, a remarkable power-conversion efficiency of 18.53 % is obtained in the ternary PSC based on PTQ10 : m-BTP-PhC6 with BTP-Th as the third component, which is a significant improvement with regard to the efficiency of 17.22 % for the control binary device. Our study offers a molecular design strategy to develop a third component for building ternary PSCs in terms of crystallinity and miscibility regulation.     

Cheap thiamine hydrochloride as efficient catalyst for synthesis of 4<Emphasis Type="Italic">H</Emphasis>-benzo[<Emphasis Type="Italic">b</Emphasis>]pyrans in aqueous ethanol

Preparation of pharmaceutically active 2-amino-4H-pyran derivatives has been achieved using cheap thiamine hydrochloride as catalyst. A wide range of aromatic aldehydes easily undergo condensation with malononitrile and several kinds of 1,3-cyclohexanedione under mild condition to afford the desired product with good purity in excellent yield. This protocol has various advantages as a simple, clean, and environmentally benign three-component process.     

Analysis and Improvement of Reflection-type Transverse Modulation Optical Voltage Sensors

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