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Good Miscibility (good + miscibility)

Distribution by Scientific Domains

Polymers and Materials Science	100%

Selected Abstracts

Phase Segregation in Thin Films of Conjugated Polyrotaxane, Poly(ethylene oxide) Blends: A Scanning Force Microscopy Study,

ADVANCED FUNCTIONAL MATERIALS, Issue 6 2007
L. Sardone
Abstract Scanning force microscopy (SFM) is used to study the surface morphology of spin-coated thin films of the ion-transport polymer poly(ethylene oxide) (PEO) blended with either cyclodextrin (CD)-threaded conjugated polyrotaxanes based on poly(4,4,-diphenylene-vinylene) (PDV), ,-CD,PDV, or their uninsulated PDV analogues. Both the polyrotaxanes and their blends with PEO are of interest as active materials in light-emitting devices. The SFM analysis of the blended films supported on mica and on indium tin oxide (ITO) reveals in both cases a morphology that reflects the substrate topography on the (sub-)micrometer scale and is characterized by an absence of the surface structure that is usually associated with phase segregation. This observation confirms a good miscibility of the two hydrophilic components, when deposited by using spin-coating, as suggested by the luminescence data on devices and thin films. Clear evidence of phase segregation is instead found when blending PEO with a new organic-soluble conjugated polymer such as a silylated poly(fluorene)- alt -poly(para -phenylene) based polyrotaxane (THS,,-CD,PF,PPP). The results obtained are relevant to the understanding of the factors influencing the interfacial and the intermolecular interactions with a view to optimizing the performance of light-emitting diodes, and light-emitting electrochemical cells based on supramolecularly engineered organic polymers. [source]

Miscibility and Physical Properties of Poly(3-hydroxybutyrate -co- 3-hydroxyhexanoate)/Poly(ethylene oxide) Binary Blends

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 12 2009
Fang Yu
Abstract In order to improve some inferior physical properties of bacterial poly(3-hydroxybutyrate -co- 3-hydroxyhexanoate) [P(3HB -co- 3HHx)] by blending with PEO, the miscibility, spherulite morphology, crystallization behavior and mechanical properties of P(3HB -co- 3HHx)/PEO binary biodegradable polymer blends were investigated. A good miscibility between P(3HB -co- 3HHx) with a 3HHx unit content of 11 mol-% and PEO in the amorphous state was found when the PEO weight fraction was 10,wt.-%, while the miscibility decreased dramatically when the PEO weight fraction exceeded 20,wt.-%. Strongly depending on the blend composition, the mechanical properties of P(3HB -co- 3HHx) was found to be significantly improved by blending with PEO with a weight fraction of ,5,17.5,wt.-%. [source]

Role of Star-Like Hydroxylpropyl Lignin in Soy-Protein Plastics

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 5 2006
Ming Wei
Abstract Summary: Star-like hydroxypropyl lignin (HL) was compounded into soy protein isolated (SPI) to develop a potential biodegradable plastic with better mechanical performance than pure sheet-SPI. The structure and properties of the composite materials were characterized by WAXD, DSC, SEM, TEM and tensile tests. The addition of just 2 wt.-% HL resulted in tensile strength (,b) of 16.8 MPa, 2.3 times that of pure sheet-SPI, with no accompanying decrease in elongation at break as a result of strong interaction and with good miscibility among components. As the HL content increased, the HL molecules could self-aggregate as oblate supramolecular domains, while the stronger interactions between HL and glycerol resulted in the detaching of glycerol from the SPI matrix. It can be concluded that the insertion of HL as single molecules into the SPI matrix would provide materials with optimum mechanical properties. Compared with other lignin/SPI composites, the stretching chains on HL play a key role in the improvement of mechanical properties because of a stronger adhesion of HL onto the SPI matrix as well as the interpenetration of SPI into supramolecular HL domains. Schematic illustration of the supramolecular domain created by the aggregation of hydroxypropyl lignin, which can interpenetrate with soy protein isolate. [source]

Synthesis of styrene,maleic anhydride random copolymer and its compatibilization to poly(2,6-dimethyl-1,4-phenylene ether)/brominated epoxy resin

POLYMER INTERNATIONAL, Issue 6 2003
Guozheng Liang
Abstract Styrene,maleic anhydride random copolymer (R-SMA7.5), with a low content of maleic anhydride (MAH) of about 7.5 mol%, has been prepared, and the copolymer was characterized by fourier-transform infrared (FTIR) and 13C NMR techniques showing that the product contained only random copolymer without blocks. The miscibility between poly(2,6-dimethyl-1,4-phenylene ether) (PPE) and R-SMA, was investigated by differential scanning calorimetry (DSC), showing that PPE was miscible with R-SMA synthesized in our laboratory over the entire composition with low MAH content. A blend of R-SMA18 (MAH content is about 18 mol%) and PPE was also studied by DSC, which showed that PPE was immiscible when R-SMA was the major component, although it was miscible with limited composition. FTIR investigation showed that R-SMA could react with bromide epoxy (BEP) resin at high temperature (180°). The heat-resistance and mechanical properties of R-SMA/PPE/BEP systems were tested and analyzed, and results indicated that R-SMA could improve the miscibility of PPE and BEP with increasing Tg of the BEP phase and decreasing the Tg of the PPE slightly, improving the breaking elongation and breaking energy, which resulted from good miscibility between PPE and BEP with R-SMA as the compatibilizer. Finally, the properties of the composites (copper clad laminate) with R-SMA7.5 are studied and discussed. Copyright © 2003 Society of Chemical Industry [source]

Polymeric liquid crystals: cholesteric superstructure from blends of hydroxypropylcellulose esters

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 8 2003
Estella Bianchi
Abstract n-Butyric, iso-butyric, n-valeric and iso-valeric esters of hydroxypropylcellulose were synthesized. Their behaviors, in terms of cholesteric structure, glass (Tg) and anisotropic-isotropic (Ti) transition temperatures are compared to results in the literature. A 6,8 month time period from sample preparation has no influence on the cholesteric phase characteristics. Six binary blends may be formed from the four esters. They show only a Tg value at each composition, which suggests a good miscibility among the components. However, positive deviation of linearity of Tg vs. composition varies from one pair to another. Analysis of the absorption curves in UV-vis spectra show that three pairs form a single cholesteric helix containing both components while other three give a only nematic phase. Colors changing from red to violet are shown for blends of n-butyric and iso-butyric esters at different weight ratio. Copyright © 2003 John Wiley & Sons, Ltd. [source]