Studies on the miscibility and phase structure in blends of poly(epichlorohydrin) and poly(vinyl acetate)

The miscibility of atactic poly(epichlorohydrin) (aPECH) with poly(vinyl acetate) (PVAc) was examined under two different conditions: (i) in dilute solution, using vicometeric measurements and (ii) as cast films, using differential scanning calorimetric (DSC) and FT-infrared spectroscopy. Phase separation on heating, i.e. lower critical solution temperature (LCST) behavior of the aPECH/PVAc blends was examined by the measurement of transmitted light intensity against temperature. From viscosity measurements, the Krigbaum-Wall polymer-polymer interaction (ΔB) was evaluated. The DSC results show that the aPECH/PVAc blends are miscible as evidenced by the observation of a single composition-dependent glass-transition temperature (T_g) which is well described by the Couchman and Gordon Taylor models. The Flory-Huggins interaction parameter (χ₁₂) calculated from the T_g-method was negative and equal to −0.01, indicating a relatively low interaction strength. The FT-IR results match very well with those of DSC. The cloud point phenomenon is thermodynamically driven but phase separation, once taken place, is diffusion controlled in normal accessible time.     

Miscibility and interactions in poly(methylthiomethyl methacrylate)/poly(vinyl alcohol) blends

Poly(methylthiomethyl methacrylate) (PMTMA) is miscible with poly(vinyl alcohol) (PVA) over the whole composition range as shown by the existence of a single glass transition temperature in each blend. The interaction between PMTMA and PVA was examined by Fourier transform infrared spectroscopy, solid-state nuclear magnetic resonance spectroscopy and X-ray photoelectron spectroscopy. The interactions mainly involve the hydroxyl groups of PVA and the thioether sulfur atoms of PMTMA, and the involvement of the carbonyl groups of PMTMA in interactions is not significant. The measurements of proton spin-lattice relaxation time reveal that PMTMA and PVA do not mix intimately on a scale of 1-3 nm, but are miscible on a scale of 20-30 nm. In comparison, we have previously found that PMTMA is miscible with poly(p-vinylphenol) and the two polymers mix intimately on a scale of 1-3 nm.     

Miscibility of C60-end-capped poly(ethylene oxide) with poly(vinyl chloride)

The miscibility of blends of single [60]fullerene (C₆₀)-end-capped poly(ethylene oxide) (FPEO) or double C₆₀-end-capped poly(ethylene oxide) (FPEOF) with poly(vinyl chloride) (PVC) has been studied. Similar to poly(ethylene oxide) (PEO), both FPEO and FPEOF are also miscible with PVC over the entire composition range. X-ray photoelectron spectroscopy showed the development of a new low-binding-energy Cl2p doublet and a new high-binding-energy O1s peak in FPEO/PVC blends. The results show that the miscibility between FPEO and PVC arises from hydrogen bonding interaction between the α-hydrogen of PVC and the ether oxygen of FPEO. From the melting point depression of PEO, FPEO or FPEOF in the blends, the Flory-Huggins interaction parameters were found to be −0.169, −0.142, −0.093 for PVC/PEO, PVC/FPEO and PVC/FPEOF, respectively, demonstrating that all the three blend systems are miscible in the melt. However, the incorporation of C₆₀ slightly impairs the interaction between PEO and PVC.     

Miscibility and crystallization of poly(ethylene succinate)/poly(vinyl phenol) blends

Miscibility of biodegradable poly(ethylene succinate) (PES)/poly(vinyl phenol) (PVPh) blends has been studied by differential scanning calorimetry (DSC) in this work. PES is found to be miscible with PVPh as shown by the existence of single composition dependent glass transition temperature over the entire composition range. Spherulitic morphology and the growth rates of neat and blended PES were investigated by optical microscopy (OM). Both neat and blended PES show a maximum growth rate value in the crystallization temperature range of 45-65 °C, with the growth rate of neat PES being higher than that of blended PES at the same crystallization temperature. The overall crystallization kinetics of neat and blended PES was also studied by DSC and analyzed by the Avrami equation at 60 and 65 °C. The crystallization rate decreases with increasing the temperature for both neat and blended PES. The crystallization rate of blended PES is lower than that of neat PES at the same crystallization temperature. However, the Avrami exponent n is almost the same despite the blend composition and crystallization temperature, indicating that the addition of PVPh does not change the crystallization mechanism of PES but only lowers the crystallization rate.     

Miscibility of biodegradable aliphatic polyester and poly(vinyl acetate) blends

We report miscibility behavior for synthetic biodegradable aliphatic polyester (BDP) and poly(vinyl acetate) (PVAc) blends by investigating their thermal, rheological, and mechanical properties. Two separate glass transition temperature peaks for the BDP/PVAc blends proved that these blend systems are immiscible. From the rheological measurement, the shear viscosity as a function of shear rate is observed to increase with increasing PVAc content in BDP/PVAc blends, since PVAc has a relatively high molecular weight compared to BDP. Moreover, BDP blends with 10 wt % PVAc have excellent mechanical properties. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1348–1352, 2000     

高分子量聚醋酸乙烯酯的醇解研究

探讨了催化剂浓度、醇解温度和反应时间等对高分子量聚醋酸乙烯酯醇解的影响,得出高分子量聚醋酸乙烯酯醇解的适合条件。     

Miscibility and interactions in polystyrene and sodium sulfonated polystyrene with poly(vinyl methyl ether) PVME blends. Part II. FTIR

The miscibility and specific interactions of polystyrene (PS) and sodium sulfonated polystyrene (Na-SPS) with poly(vinyl methyl ether) (PVME) blends (ranging from 10 to 90% PS by weight) were examined experimentally by FTIR spectroscopy. The FTIR studies at different temperatures have shown that changes in spectra of polymer blends, as reported in the literature can be explained by temperature changes in pure homopolymers. This indicates that molecular interactions, which are responsible for miscibility, are not detectable by infrared absorptions and are therefore of unspecific strength and location. The FTIR of SPS/PVME blends show that sulfonate groups of PS affect polymer miscibility through changes in configuration of molecules, rather than through direct interaction with the PVME.     

聚乙烯醇缩甲乙醛改性酚醛树脂的热稳定性研究

以苯酚、甲醛、聚乙烯醇缩甲乙醛为原料,合成了改性酚醛树脂,通过红外光谱表征了聚乙烯醇缩甲乙醛改性酚醛树脂的结构,并通过TGA分析了聚乙烯醇缩甲乙醛改性酚醛树脂的热性能。结果表明:聚乙烯醇缩甲乙醛改性的酚醛树脂初始热分解温度为271.8℃,796℃时失重76.43%,与聚乙烯醇缩丁醛改性的酚醛树脂相比,由于缩短了酚醛树脂的碳链,热稳定性增加。     

Poly(butylene succinate)/poly(vinyl phenol) blends. Part 1. Miscibility and crystallization

Miscibility has been investigated in blends of poly(butylene succinate) (PBSU) and poly(vinyl phenol) (PVPh) by differential scanning calorimetry in this work. PBSU is miscible with PVPh as shown by the existence of single composition dependent glass transition temperature over the entire composition range. In addition, the polymer–polymer interaction parameter, obtained from the melting depression of PBSU using the Nishi–Wang equation, is composition dependent, and its value is always negative. This indicates that PBSU/PVPh blends are thermodynamically miscible in the melt. Preliminary morphology study of PBSU/PVPh blends was also studied by optical microscopy (OM). OM experiments show the spherulites of PBSU become larger with the PVPh content, indicative of a decrease in the nucleation density, and the coarseness of PBSU spherulites increases too with increasing the PVPh content in the blends.     

Phase separation in styrenated polyester resin containing a poly(vinyl acetate) low-profile additive

Scanning electron microscopy has been used to observe morphology in styrenated polyester resins containing poly(vinyl acetate) (PVA). Resins containing 8% PVA form composite spherical particles which occupy 35 vol% of the total material. It is concluded that these particles consist of resin sub-inclusions embedded in the continuous matrix of polyester resin. Increasing the PVA content to 16% results in a phase inversion: PVA forms the matrix, and the resin is present as spherical particles. These observations are interpreted with the aid of a ternary diagram.     

Poly(hydroxyether sulfone) and its blends with poly(ethylene oxide): miscibility, phase behavior and hydrogen bonding interactions

Poly(hydroxyether sulfone) (PHES) was synthesized through polycondensation of bisphenol S with epichlorohydrin. It was characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy and differential scanning calorimetry (DSC). The miscibility in the blends of PHES with poly(ethylene oxide) (PEO) was established on the basis of the thermal analysis results. DSC showed that the PHES/PEO blends prepared by casting from N,N-dimethylformamide (DMF) possessed single, composition-dependent glass transition temperatures (T_gs), indicating that the blends are miscible in amorphous state. At elevated temperatures, the PHES/PEO blends underwent phase separation. The phase behavior was investigated by optical microscope and the cloud point curve was determined. A typical lower critical solution temperature behavior was observed in the moderate temperature range for this blend system. FTIR studies indicate that there are the competitive hydrogen bonding interactions upon adding PEO to the system, which was involved with the intramolecular and intermolecular hydrogen bonding interactions, i.e. -OH?OS, -OH?-OH and -OH versus ether oxygen atoms of PEO between PHES and PEO. In terms of the infrared spectroscopic investigation, it is judged that from weak to strong the strength of the hydrogen bonding interactions is in the following order: -OH?OS, -OH?-OH and -OH versus ether oxygen atoms of PEO.     

Miscibility and intermolecular specific interactions in blends of poly(hydroxyether of bisphenol A) and poly(4-vinyl pyridine)

The blends of poly(hydroxyether of bisphenol A) (phenoxy) with poly(4-vinyl pyridine) (P4VPy) were investigated by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and high-resolution solid-state nuclear magnetic resonance (NMR) spectroscopy. The single, composition-dependent glass transition temperature (T_g) was observed for each blend, indicating that the system is completely miscible. The sigmoid T_g-composition relationship is characteristic of the presence of the strong intermolecular specific interactions in the blend system. FTIR studies revealed that there was intermolecular hydrogen bonding in the blends and the intermolecular hydrogen bonding between the pendant hydroxyl groups of phenoxy and nitrogen atoms of pyridine ring is much stronger than that of self-association in phenoxy. To examine the miscibility of the system at the molecular level, the high resolution ¹³C cross-polarization (CP)/magic angle spinning (MAS) together with the high-power dipolar decoupling (DD) NMR technique was employed. Upon adding P4VPy to the system, the chemical shift of the hydroxyl-substituted methylene carbon resonance of phenoxy was observed to shift downfield in the ¹³C CP/MAS spectra. The proton spin-lattice relaxation time T₁(H) and the proton spin-lattice relaxation time in the rotating frame T_1ρ(H) were measured as a function of the blend composition. In light of the proton spin-lattice relaxation parameters, it is concluded that the phenoxy and P4VPy chains are intimately mixed on the scale of 20-30 Å.     

The thermal degradation of poly(vinyl acetate) measured by thermal analysis-Fourier transform infrared spectroscopy

The elimination process which occurs during the thermal degradation of poly(vinyl acetate) has been studied using thermal analysis-Fourier transform infrared spectroscopy. It was found that elimination of acetate groups initially began slowly, but increased as degradation proceeded due to an additional process. The increase in rate was found to depend on the concentration of unsaturated groups in the polymer chain. The activation energy for the initial step was found to be 190 kJ mol⁻¹, while that for the additional process was 130 kJ mol⁻¹. The additional process of elimination was considered to be due to a four-membered transition state, activated by double bonds adjacent to the acetate unit.     

聚醋酸乙烯乳液保护胶体的改性

介绍了聚醋酸乙烯乳液保护胶体改性的一些现状和进展。包括聚乙烯醇的缩醛化、酰基化、烷基化、醋酸乙烯共聚物皂化、添加剂改性等方法以及其他保护胶体的应用。     

Miscibility and interactions in blends and complexes of poly(4-methyl-5-vinylthiazole) with proton-donating polymers

The miscibility and interactions in blends and complexes of poly(4-methyl-5-vinylthiazole) (PMVT) with poly(p-vinylphenol) (PVPh), poly(acrylic acid) (PAA) and poly(vinylphosphonic acid) (PVPA) were studied. PMVT formed complexes with PVPA but not with PVPh and PAA. Each of the blends of PMVT with PVPh and PAA showed a single glass transition temperature (T_g), indicating miscibility. Fourier-transform infrared spectroscopic and X-ray photoelectron spectroscopic studies provided the existence of interactions in the PMVT blends and complexes. The XPS studies indicated that the thiazole nitrogen atoms are involved in hydrogen-bonding interactions with PVPh and PAA, and ionic interactions with PVPA. The sulfur atoms of PMVT also interact with PVPh, PAA and PVPA.     

Miscibility and phase behavior in blends of phenolphthalein poly(ether sulfone) and poly(hydroxyether of bisphenol A)

Miscibility and phase behavior in the blends of phenolphthalein poly(ether sulfone) (PES-C) with poly(hydroxyether of bisphenol A) (PH) were investigated by means of differential scanning calorimetry (DSC), high resolution solid state nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infrared spectroscopy (FTIR). It was found that the homogeneity of the as-prepared blends depended on the solvents used; N,N-dimethylformamide (DMF) provided the segmental mixing for PH and PES-C, which is confirmed by the behavior of single, composition-dependent glass transition temperatures (T_g's). To examine the homogeneity of the blends at the molecular level, the proton spin-lattice relaxation times in the rotating frame T_1ρ(H) were measured via ¹³C CP/MAS NMR spectroscopy as a function of blend composition. In view of the T_1ρ(H) values, it is concluded that the PH and PES-C chains are intimately mixed on the scale of 20-30 Å. FTIR studies indicate that there were the intermolecular specific interactions in this blends, involved with the hydrogen-bonding between the hydroxyls of PH and the carbonyls of PES-C, and the strength of the intermolecular hydrogen bonding is weaker than that of PH self-association. At higher temperature, the PH/PES-C blends underwent phase separation. By means of thermal analysis, the phase boundaries of the blends were determined, and the system displayed the lower critical solution temperature behavior. Thermogravity analysis (TGA) showed that the blends exhibited the improved thermal stability, which increases with increasing PES-C content.     

Manufacturing and characterizations of flexible poly(dimethylsiloxane)/poly(vinyl acetate)/polythiophene ternary composite films

ABSTRACT

In this study, polythiophene and poly(dimethylsiloxane)/poly(vinyl acetate)/polythiophene ternary composites were synthesized. The new ternary composites obtained in powder and film forms were characterized using various techniques. Magnetic properties of all the materials were analyzed by Gouy balance measurements, and it was found that their conductivity mechanism is of polaron nature. The surface structure, surface roughness, and thermal properties of the prepared samples were identified by Scanning Electron Microscopy, Atomic Force Microscopy, and Thermogravimetric Analysis, respectively. The tensile-tension test studies were performed for mechanical properties. The PDMS/PVAc/PT (6%) composite demonstrated about 50% of the maximum strain value (%) of vulcanized natural rubber.     

Miscibility and crystallization in crystalline/crystalline blends of poly(butylene succinate)/poly(ethylene oxide)

Miscibility and crystallization behavior have been investigated in blends of poly(butylene succinate) (PBSU) and poly(ethylene oxide) (PEO), both semicrystalline polymers, by differential scanning calorimetry and optical microscopy. Experimental results indicate that PBSU is miscible with PEO as shown by the existence of single composition dependent glass transition temperature over the entire composition range. In addition, the polymer-polymer interaction parameter, obtained from the melting depression of the high-T_m component PBSU using the Flory-Huggins equation, is composition dependent, and its value is always negative. This indicates that PBSU/PEO blends are thermodynamically miscible in the melt. The morphological study of the isothermal crystallization at 95 °C (where only PBSU crystallized) showed the similar crystallization behavior as in amorphous/crystalline blends. Much more attention has been paid to the crystallization and morphology of the low-T_m component PEO, which was studied through both one-step and two-step crystallization. It was found that the crystallization of PEO was affected clearly by the presence of the crystals of PBSU formed through different crystallization processes. The two components crystallized sequentially not simultaneously when the blends were quenched from the melt directly to 50 °C (one-step crystallization), and the PEO spherulites crystallized within the matrix of the crystals of the preexisted PBSU phase. Crystallization at 95 °C followed by quenching to 50 °C (two-step crystallization) also showed the similar crystallization behavior as in one-step crystallization. However, the radial growth rate of the PEO spherulites was reduced significantly in two-step crystallization than in one-step crystallization.     

Miscibility of segmented polyurethane/poly(vinyl chloride) blends

Miscibilities of segmented polyurethanes (SPUs) and poly(vinyl chloride) (PVC) or functionalized poly(vinyl chloride) (FPVC) were studied with dynamic mechanical analysis, differential scanning calorimetry, and X‐ray diffraction. Mechanical properties of the blends were also studied with tensile measurements. The miscibility of the blends depended greatly on the hard‐segment content of SPU and the existence of the functional groups. The combination of SPU with a low hard‐segment content and PVC with functional groups made the blend system miscible. Moreover, controlling the blend composition of SPU/FPVC allowed us to modify the mechanical properties of SPU, where the elongation at break was multiplied without a significant change in its tensile strength. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3022–3029, 2001     

Miscibility Studies of Poly (vinyl acetate) and Cellulose Acetate

Polymer blends of poly (vinyl acetate) (PVAc) with cellulose acetate (CA) have been prepared by solution blending, and their miscibility has been investigated by using physical techniques. Viscosity, density, and ultrasonic velocity for blend solutions at different percentages of the blend composition have been measured at 30°C. The results are discussed.