Tamer Uyar  Cristian C. Rusa  Xingwu Wang  Mariana Rusa  Jale Hacaloglu  Alan E. Tonelli 《Journal of Polymer Science.Polymer Physics》2005,43(18):2578-2593

A procedure for the formation of intimate blends of three binary polymer systems polycarbonate (PC)/poly(methyl methacrylate) (PMMA), PC/poly(vinyl acetate) (PVAc) and PMMA/PVAc is described. PC/PMMA, PC/PVAc, and PMMA/PVAc pairs were included in γ‐cyclodextrin (γ‐CD) channels and were then simultaneously coalesced from their common γ‐CD inclusion compounds (ICs) to obtain intimately mixed blends. The formation of ICs between polymer pairs and γ‐CD were confirmed by wide‐angle X‐ray diffraction (WAXD), fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). It was observed [solution ¹H nuclear magnetic resonance (NMR)] that the ratios of polymers in coalesced PC/PMMA and PC/PVAc binary blends are significantly different than the starting ratios, and PC was found to be preferentially included in γ‐CD channels when compared with PMMA or PVAc. Physical mixtures of polymer pairs were also prepared by coprecipitation and solution casting methods for comparison. DSC, solid‐state ¹H NMR, thermogravimetric analysis (TGA), and direct insertion probe pyrolysis mass spectrometry (DIP‐MS) data indicated that the PC/PMMA, PC/PVAc, and PMMA/PVAc binary polymer blends were homogeneously mixed when they were coalesced from their ICs. A single, common glass transition temperature (T_g) recorded by DSC heating scans strongly suggested the presence of a homogeneous amorphous phase in the coalesced binary polymer blends, which is retained after thermal cycling to 270 °C. The physical mixture samples showed two distinct T_gs and ¹H T_1ρ values for the polymer components, which indicated phase‐separated blends with domain sizes above 5 nm, while the coalesced blends exhibited uniform ¹H spin‐lattice relaxation values, indicating intimate blending in the coalesced samples. The TGA results of coalesced and physical binary blends of PC/PMMA and PC/PVAc reveal that in the presence of PC, the thermal stability of both PMMA and PVAc increases. Yet, the presence of PMMA and PVAc decreases the thermal stability of PC itself. DIP‐MS observations suggested that the degradation mechanisms of the polymers changed in the coalesced blends, which was attributed to the presence of molecular interactions between the well‐mixed polymer components in the coalesced samples. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2578–2593, 2005  相似文献   

    

H. L. Huang  S. H. Goh  Doreen M. Y. Lai  A. T. S. Wee  C. H. A. Huan 《Journal of Polymer Science.Polymer Physics》2004,42(7):1145-1154

The miscibility and underlying hydrogen‐bonding interactions of blends of a fluorinated copolymer containing pyridine and a nonfluorinated copolymer containing methacrylic acid were studied with differential scanning calorimetry (DSC), transmission Fourier transform infrared (TX‐FTIR) spectroscopy, and X‐ray photoelectron spectroscopy (XPS), whereas the surface properties of the blends were investigated with contact‐angle measurements, time‐of‐flight secondary‐ion mass spectroscopy, XPS, and attenuated total reflectance Fourier transform infrared spectroscopy. DSC studies showed that the presence of a sufficient amount of 4‐vinylpyridine units in the fluorinated copolymer produced miscible blends with the nonfluorinated copolymer containing methacrylic acid. TX‐FTIR and XPS showed the existence of pyridine–acid interpolymer hydrogen‐bonding interactions. Even though the anchoring effect of hydrogen bonding hindered the migration of the fluorinated component to the blend surface, it could not completely eliminate the surface enrichment of the fluorinated component and the surface rearrangement of the fluorinated pendant chain. The air–blend interface was mainly occupied by the fluorinated pendant chain, and the surface energies of the blends were extremely low, even with only 1.5 wt % of the fluorinated component in the blends. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1145–1154, 2004  相似文献   

    

Jieh‐Ming Huang 《Journal of Polymer Science.Polymer Physics》2004,42(9):1694-1704

We prepared blends of poly(butylene‐2,6‐naphthalate) (PBN) and poly(ether imide) (PEI) by solution‐casting from dichloroacetic acid solutions. The miscibility, crystallization, and melting behavior of the blends were investigated with differential scanning calorimetry (DSC) and dynamic mechanical analysis. PBN was miscible with PEI over the entire range of compositions, as shown by the existence of single composition‐dependent glass‐transition temperatures. In addition, a negative polymer–polymer interaction parameter was calculated, with the Nishi–Wang equation, based on the melting depression of PBN. In nonisothermal crystallization investigations, the depression of the crystallization temperature of PBN depended on the composition of the blend and the cooling rate; the presence of PEI reduced the number of PBN segments migrating to the crystallite/melt interface. Melting, recrystallization, and remelting processes occurring during the DSC heating scan caused the occurrence of multiple melting endotherms for PBN. We explored the effects of various experimental conditions on the melting behavior of PBN/PEI blends. The extent of recrystallization of the PBN component during DSC heating scans decreased as the PEI content, the heating rate, the crystallization temperature, and the crystallization time increased. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1694–1704, 2004  相似文献   

    

Dongqing Zhuang  Jinfeng Guo  Yunxiang Zhang 《Macromolecular rapid communications》2002,23(2):109-112

Hydrophobically modified poly(acrylic acid) with hydrocarbon groups (PH), fluorocarbon groups (PF) or both of them (PHF) were synthesized. Their interactions with the HC nonionic surfactant Np7.5 and FC nonionic surfactant FC171 were investigated and compared by means of rheological measurements. Co‐modification of the polyelectrolyte improves the miscibility of the hydrophobic groups with either Np7.5 or FC171. In the presence of salt, associations of PHF and PH with Np7.5 evolved differently.  相似文献   

    

Jae Gyeong Jung  Young Chan Bae 《Journal of Polymer Science.Polymer Physics》2010,48(2):162-167

We have developed a new Flory‐Huggins model by adding a specific interaction parameter derived from a modified double‐lattice model for the Helmholtz energy of mixing for binary liquid mixtures. This model is very simple and could be easily integrated into engineering applications. Using this revised model, we can successfully describe the phase behavior of polymer solutions with an upper critical solution temperature (UCST), a lower critical solution temperature (LCST), both UCST and LCST, and a closed miscibility loop. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 162–167, 2010  相似文献   

    

Siti Sarah Abdul Rahman  Daisuke Kawaguchi  Daisaku Ito  Atsushi Takano  Yushu Matsushita 《Journal of Polymer Science.Polymer Physics》2009,47(22):2272-2280

The phase behavior of statistical copolymers composed of (4‐tert‐butylstyrene) (B) and (4‐tert‐butoxystyrene) (O), abbreviated as s‐BO, with polyisoprene (I) was investigated by optical microscopic (OM) observation and small‐angle neutron scattering (SANS) measurements. It has been known that B/I blend shows lower critical solution temperature (LCST) type phase diagram, while O/I blend has upper critical solution temperature (UCST) type one. Several blends of s‐BOs having mol fraction of B, m_B, comparable to 0.50, with I showed both UCST and LCST type phase diagram. Furthermore, UCST type phase behavior was observed for blends having small m_B, while LCST type one was for that of large m_B at all used temperatures. Hence, the phase behavior of s‐BO/I blend can be understood as a result of the competition of two interactions having opposite temperature dependence. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 2272–2280, 2009  相似文献   

    

Ioannis M. Kalogeras  Witold Brostow 《Journal of Polymer Science.Polymer Physics》2009,47(1):80-95

Knowledge of the glass transition temperatures (T_gs) as function of composition reflects miscibility (or lack of it) and is decisive for virtually all properties of polymer‐based materials. In this article, we analyze single blend‐average and effective T_gs of miscible polymer blends in full concentration ranges. Shortcomings of the extant equations are discussed to support the need for an alternative. Focusing on the deviation from a linear relationship, defined as ΔT_g = T_g ? φ₁T_g,1 ? φ₂T_g,2 (where φ_i and T_g,i are, respectively, the weight fraction and the T_g of the i‐th component), a recently proposed equation for the blend T_g as a function of composition is tested extensively. This equation is simple; a quadratic polynomial centered around 2φ₁ ? 1 = 0 is defined to represent deviations from linearity, and up to three parameters are used. The number of parameters needed to describe the experimental data, along with their magnitude and sign, provide a measure of the system complexity. For most binary polymer systems tested, the results obtained with the new equation are better than those attained from existing T_g equations. The key parameter of the equation a₀ is related to parameters commonly used to represent intersegmental interactions and miscibility in binary polymer blends. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 80–95, 2008  相似文献   

    

Sorkunde Eceolaza  Marian Iriarte  Cristina Uriarte  Agustin Etxeberria 《Journal of Polymer Science.Polymer Physics》2009,47(16):1625-1634

In this work, the transport properties of the system formed by polyamide 6 (PA6) and polyhydroxyamino‐ether resin (PHAE) have been studied after characterizing the miscibility behavior. A single glass transition has been observed using differential scanning calorimetry that usually means total miscibility, but measurements by solid‐state cross‐polarization magic angle spinning NMR have shown that this system is only partially miscible, in good agreement with phase behavior reported before. Both carbon dioxide and water vapor transport properties of PA6/PHAE blends have been measured. For both penetrants, permeability coefficient shows an interesting negative deviation from the additive value, even the barrier character to carbon dioxide of pure PHAE is maintained up to 60 % in PA6 composition. Besides, PHAE reduces the plasticization effect of water in PA6. These improvements are very interesting for the PA 6 due to its wide use in packaging applications. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1625–1634, 2009  相似文献   

    

Ashok K. Das  Di‐Yao Hsu  Po‐Da Hong 《Macromolecular theory and simulations》2011,20(1):19-30

Densities and viscosities of a series of blends of poly(ethylene glycol) (PEG) and poly(ethylene glycol‐ran‐propylene glycol) (PEG‐ran‐PPG) were measured at a temperature above the melting point. The density and viscosity data were fitted with analytical functions involving the volume fraction of PEG, ϕ_PEG. Stress relaxation curves for the pure components and blends were obtained through Monte Carlo (MC) simulations. A typical stress relaxation curve exhibits a fast mode that represents energetic‐interactions‐driven motion and a slow mode that originates from the entropy‐driven motion. Flory–Huggins interaction parameters (χ) for the blends are much smaller than the critical values (χ_critical). The calculation of χ and χ_critical provides important clues for polymer blend processing.

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Osamu Urakawa  Hiroyoshi Ikuta  Shogo Nobukawa  Toshiyuki Shikata 《Journal of polymer science. Part A, Polymer chemistry》2008,46(23):2556-2565

Thermal concentration fluctuation in the blends of deuterated poly(ethylene oxide) (dPEO) and poly(vinyl acetate-co-vinyl alcohol) [P(VAc-VOH)] with various VOH contents f_OH were examined by small angle neutron scattering techniques at a fixed blend composition, dPEO/P(VAc-VOH) = 20/80 which is close to the critical composition. Blends at the highest f_OH (=0.35) showed a non-Lorentzian scattering profile: specifically the scattering intensities at the low q (angle) region were suppressed compared to those expected from the random phase approximation (RPA) theory. However, for the blends at lower f_OH (≤0.28), the profiles could be represented by the RPA. Using the RPA we determined effective values of the Flory-Huggins interaction parameter χ_eff as a function of f_OH (=0–0.28). The χ_eff showed the minimum around f_OH = 0.1–0.18 meaning the highest miscibility of the blend at these f_OH. On the basis of the random copolymer theory, we evaluated the three interaction parameters χ_Ac–EO, χ_EO–OH, and χ_Ac–OH separately from the χ_eff(f_OH) and found the order of magnitude; χ_Ac–EO < 0 < χ_EO–OH < χ_Ac–OH. The largest positive χ_Ac–OH showing intrachain interaction in the P(VAc-VOH) copolymer was concluded to be the origin of the enhanced miscibility at around f_OH = 0.1–0.18. On the basis of the Coleman and Painter's theory, the effects of hydrogen bonding on these three χ_A-B were discussed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2556–2565, 2008  相似文献