Miscibility enhancement through hydrogen bonding interaction of biodegradable poly(3‐hydroxybutyrate) blending with poly(styrene‐co‐vinyl phenol) copolymer

Differential scanning calorimetry, one‐ and two‐dimensional Fourier transform infrared (FTIR), and solid state nuclear magnetic resonance (NMR) spectroscopy have been used to investigate the miscibility of and specific interactions between poly(styrene‐co‐vinyl phenol) (PSOH) and poly(3‐hydroxybutyrate) (PHB) upon varying the vinyl phenol content of the PSOH copolymer. The FTIR and solid state NMR spectra revealed that the phenol units of PVPh interact with the carbonyl groups of PHB through intermolecular hydrogen bonding. A miscibility window exists when the vinyl phenol fraction in the copolymer is greater than 22 mol % in the PSOH/PHB blend system, as predicted using the Painter–Coleman association model. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Blends of poly(ethylene oxide) and poly(4-vinylphenol-co-2-hydroxyethyl methacrylate): thermal analysis, morphological behaviour and specific interactions

DSC and optical microscopy were used to determine the miscibility and crystallinity of blends of poly(ethylene oxide) (PEO) with poly(4-vinylphenol-co-2-hydroxyethyl methacrylate) (PVPh-HEM). A single glass transition temperature was observed for all blends, indicating miscibility. A progressive decrease in the degree of crystallinity and in the size of the PEO spherullites is observed, as PVPh-HEM is added. FTIR was used to probe the intermolecular specific interactions of the blends and the miscibility of the blend is mainly attributed to PVPh-HEM/PEO intermolecular interactions via hydrogen bonding.     

Polymer nanotube nanocomposites: Correlating intermolecular interaction to ultimate properties

Polymer nanocomposite films containing 5 wt% single-walled carbon nanotubes (SWNT) or 5 wt% multi-walled carbon nanotubes (MWNT) with random copolymers of styrene and vinyl phenol were processed from dimethyl formamide solutions. Vinyl phenol mole ratio in the copolymer was 0, 10, 20, 30, and 40%. FTIR analysis indicates that the composites containing the copolymer with 20% vinyl phenol exhibit the maximum intermolecular interactions (hydrogen bonding) between the hydroxyl group of the vinyl phenol and the carbon nanotube functional groups. Tensile properties and electrical conductivity also are the highest in the samples containing the copolymer with 20% vinyl phenol. Thus, these results show that the optimization of the extent of intermolecular interactions between a polymer chain and a carbon nanotube results in an optimal increase in macroscopic properties. Moreover, the extent of intermolecular hydrogen bonding can be improved by optimizing the accessibility of the functional groups to participate in the non-covalent interaction. In this system, this optimization is realized by control of the amount of vinyl phenol in the copolymer, i.e. the copolymer composition.     

Intra- and Intermolecular Hydrogen Bonding in Miscible Blends of CO2/Epoxy Cyclohexene Copolymer with Poly(Vinyl Phenol)

In this study, we synthesized a poly(cyclohexene carbonate) (PCHC) through alternative ring-opening copolymerization of CO₂ with cyclohexene oxide (CHO) mediated by a binary LZn₂OAc₂ catalyst at a mild temperature. A two-dimensional Fourier transform infrared (2D FTIR) spectroscopy indicated that strong intramolecular [C–H···O=C] hydrogen bonding (H-bonding) occurred in the PCHC copolymer, thereby weakening its intermolecular interactions and making it difficult to form miscible blends with other polymers. Nevertheless, blends of PCHC with poly(vinyl phenol) (PVPh), a strong hydrogen bond donor, were miscible because intermolecular H-bonding formed between the PCHC C=O units and the PVPh OH units, as evidenced through solid state NMR and one-dimensional and 2D FTIR spectroscopic analyses. Because the intermolecular H-bonding in the PCHC/PVPh binary blends were relatively weak, a negative deviation from linearity occurred in the glass transition temperatures (T_g). We measured a single proton spin-lattice relaxation time from solid state NMR spectra recorded in the rotating frame [T_1ρ(H)], indicating full miscibility on the order of 2–3 nm; nevertheless, the relaxation time exhibited a positive deviation from linearity, indicating that the hydrogen bonding interactions were weak, and that the flexibility of the main chain was possibly responsible for the negative deviation in the values of T_g.     

Miscibility and interactions in poly(2,2,3,3,3-pentafluoropropyl methacrylate-co-4-vinylpyridine)/poly(p-vinylphenol) blends

The miscibility and specific interactions in poly(2,2,3,3,3-pentafluoropropyl methacrylate-co-4-vinylpyridine) (PFX, X=0, 28, 40 or 54, denoting the mol% of 4-vinylpyridine unit in the copolymer)/poly(p-vinylphenol) (PVPh) blends have been studied by differential scanning calorimetry (DSC), atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). DSC studies show that PF0 is immiscible with PVPh, and the presence of a sufficient amount of 4-vinylpyridine units in the copolymer produces miscible blends. AFM images also clearly show that the blends change from heterogeneous to homogeneous upon the incorporation of 4-vinylpyridine unit into the copolymer. FTIR and XPS show the existence of inter-polymer hydrogen bonding between PFX and PVPh. The intensity of the inter-polymer hydrogen bonding increases with increasing 4-vinylpyridine content in the copolymer.     

Miscibility with positive deviation in Tg-composition relationship in blends of poly(2-vinyl pyridine)-block-poly(ethylene oxide) and poly(p-vinyl phenol)

Phase behavior and miscibility with positive deviation from linear T_g-composition relationship in a copolymer/homopolymer blend system, poly(2-vinyl pyridine)-block-poly(ethylene oxide) (P2VP-b-PEO)/poly(p-vinyl phenol) (PVPh), were investigated by differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR) and solid-state ¹³C nuclear magnetic resonance (¹³C NMR), optical microscopy (OM), and scanning electron microscopy (SEM). Optical and electron microscopy results as well as NMR proton spin-lattice relaxation times in laboratory frame () all confirmed the miscibility as judged by the T_g criterion using DSC. In comparison to the literature result on a homopolymer/homopolymer blend of P2VP/PVPh, fitting with the Kwei equation on the T_g-composition relationship for the block-copolymer/homopolymer blend of P2VP-b-PEO/PVPh blend system yielded a smaller q value (q = 120) for P2VP-b-PEO/PVPh than that for P2VP/PVPh blend (q = 160). The FT-IR and ¹³C NMR results revealed hydrogen-bonding interactions between the pendant pyridine group of P2VP-b-PEO and phenol unit in PVPh, which is responsible for the noted positive deviation of the T_g-composition relationship. Comparison of the shifts of hydroxyl IR absorbance band, reflecting the average strength of H-bonding, indicates a decreasing order of P2VP/PVPh > P2VP-b-PEO/PVPh > PEO/PVPh blends. The PEO block in the copolymer segment tends to defray the interaction strength in the P2VP-b-PEO/PVPh blends because of relative weaker interaction between PEO and PVPh than that between P2VP and PVPh pairs. A comparative ternary (P2VP/PEO)/PVPh blend was also studied as the controlling experiments for comparison to the P2VP-b-PEO/PVPh blend. The thermal behavior and interaction strength in (P2VP/PEO)/PVPh ternary blends are discussed with those in the P2VP-b-PEO/PVPh copolymer/homopolymer blend.     

Concerning the miscibility of poly(vinyl phenol) blends — FTi.r. study

The results of a Fourier transform infrared study of poly(vinyl phenol) (PVPh) blends containing a number of chemically and structurally dissimilar polymers are presented. These polymers include the polyesters poly(ε-caprolactone) and poly(?-propiolactone); poly(vinyl alkyl ethers) where the alkyl groups are methyl, ethyl and isobutyl respectively; poly(ethylene oxide) and poly(vinyl pyrrolidone). All of these PVPh blends, with the exception of that containing poly(vinyl isobutyl ether), exhibit infrared spectral features consistent with a significant degree of mixing. Intermolecular hydrogen bonding interactions involving the PVPh hydroxyl group and either the carbonyl or ether oxygen moieties of the other polymers in the blend are identified. The relative strengths of these intermolecular interactions are discussed together with ramifications pertinent to the overall subject of polymer miscibility.     

Miscibility of poly(tetrahydrofurfuryl methacrylate) and poly(tetrahydropyranyl-2-methacrylate) with some chlorine-containing polymers

The miscibility of poly(tetrahydrofurfuryl methacrylate) (PTHFMA) and poly(tetrahydropyranyl-2-methacrylate) (PTHPMA) with some chlorine-containing polymers was studied by differential scanning calorimetry (DSC). PTHPMA was found to be miscible with poly(vinyl chloride) (PVC), polyepichlorohydrin (PECH), and a vinylidene chloride/vinyl chloride copolymer [P (VDC/VC)] and only partially miscible with an epichlorohydrin/ethylene oxide copolymer [P (ECH/EO)]. PTHFMA was shown to be miscible with PECH and P(VDC/VC), but its miscibility with P(ECH/EO) is composition-dependent. Information about interactions between components in PTHFMA/P (VDC/VC) and PTHPMA/P(VDC/VC) blends was estimated from melting-point depression. The interaction parameters B were found to be ?1.7 and ?3.6 J/cm³ for PTHFMA/P(VDC/VC) and PTHPMA/P(VDC/VC) blend systems, respectively. The miscibility behavior of PTHFMA and PTHPMA is compared to that of poly(cyclohexyl methacrylate).     

Miscibility enhancement on the immiscible poly (vinyl pyrrolidone) and poly (ethyl methacrylate) with poly (vinyl phenol)

The miscibility behavior of ternary blends of poly (vinyl phenol) (PVPh)/poly (vinyl pyrrolidone) (PVP)/poly (ethyl methacrylate) (PEMA) was investigated mainly with calorimetry. PVPh is miscible with both PVP and PEMA on the basis of the single T_g observed over the entire composition range. FTIR was used to study the hydrogen bonding interaction between the hydroxyl group of PVPh and the carbonyl group of PVP and PEMA at various compositions. Furthermore, the addition of PVPh is able to enhance the miscibility of the immiscible PVP/PEMA and eventually transforms it into a miscible blend, especially when the ratio between PVP/PEMA is 3:1, probably because of favorable physical interaction. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1205–1213, 2006     

Viscosimetric study of poly(vinyl alcohol)/poly(styrenesulfonic acid) miscibility in dilute aqueous solution

The miscibility of poly(vinyl alcohol) (PVA) and poly(styrenesulfonic acid) (PSSA) in dilute aqueous solutions was studied by a viscosimetric method. At a constant molecular weight of PSSA, it was found that the miscibility of both polymers increases with the molecular weight and the number of acetate groups of the PVA samples (1 and 12% unhydrolyzed sites). Moreover, this miscibility increases slightly with the total mixture concentration in the interval 1–2 g/dL. By comparison of the results of reduced viscosity of PVA/PSSA and PVA/poly(sodium styrenesulfonate) (PSSNa) mixtures, it has been deduced that the miscibility of two polymers is due mainly to intermolecular interactions between the hydroxyl and sulfonic groups of PVA and PSSA, respectively. These groups act as acceptors and donors of hydrogen bonds which are the responsible for polymers' miscibility. © 1996 John Wiley & Sons, Inc.     

Morphology and deformation behavior of polymer blends made of poly(styrene-co-styrenesulfonic acid) and poly(methyl methacrylate-co-4-vinylpyridine)

The effect of a small amount of ionic groups (interactions) on the morphology and deformation behavior of stoichiometric blends made of poly(styrene-co-styrenesulfonic acid) (SPS) and poly(methyl methacrylate-co-4-vinylpyridine) (MVP) was investigated by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). FTIR data revealed that intermolecular ion-ion interactions were formed between SPS and MVP polymers, arising from proton transfer from sulfonic acid groups to pyridine groups upon blending. TEM observations show that the morphology of the blends changes from macroscopic phase separation to microscopic phase separation, and to miscibility, with increasing ion content of the blends from 0 to 6 mol%. Correspondingly, deformation behavior of the blends changes from crazing only, to curved and branched crazing, and to crazing plus shear deformation. Such changes in deformation mode can be understood as arising from the morphological changes and the increase of ‘effective’ strand density due to the formation of ionic cross-links in the blends.     

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.     

Influence of tacticity of poly(methyl methacrylate) on the compatibility with poly(vinyl phenol)

Isotactic, atactic, and syndiotactic poly(methyl methacrylate) (PMMA) were mixed with poly(vinyl phenol) (PVPh) separately in tetrahydrofuran to make three polymer blend systems. Differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy were used to study the miscibility of these blends. Isotactic PMMA was found to be more miscible with PVPh than atactic or syndiotactic PMMA. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1773–1780, 1997     

Miscibility and carbon dioxide transport properties of poly(3-hydroxybutyrate) (iPHB) and its blends with different copolymers of styrene and vinyl phenol

This work summarizes the miscibility and transport properties of different polymer blends obtained by mixing a bacterial, isotactic poly(3-hydroxybutyrate) (iPHB) with copolymers of styrene and vinyl phenol (Sty-co-VPh copolymers). Given that iPHB and pure commodity poly(styrene) (PS) form immiscible blends, PS has been modified by copolymerizing it with vinyl phenol (VPh) units, in an attempt to promote blend miscibility. VPh units have appropriate functional groups that interact with iPHB ester moieties. The potential miscibility was investigated by differential scanning calorimetry (DSC) measuring the glass transition temperatures of blends of different compositions. As an additional test, the interaction parameter between the two components, using the iPHB melting point depression caused by the second component, was also measured. Copolymers containing less than 90% styrene showed miscibility with iPHB.Given the remarkable barrier properties of iPHB to gases and vapours, the study has been completed by measuring transport properties of carbon dioxide through different iPHB/Sty-co-VPh copolymer blends, using gravimetric sorptions in a Cahn electrobalance. A clear difference was observed between the behaviour of rubbery blends and those that exhibit a glassy behaviour at the selected experimental temperature (303 K).     

Miscibility enhancement on the immiscible binary blend of poly(vinyl acetate) and poly(vinyl pyrrolidone) with bisphenol A

The miscibility behavior and hydrogen bonding of ternary blends of bisphenol A (BPA)/poly(vinyl acetate) (PVAc)/poly(vinyl pyrrolidone) (PVP) were investigated by using differential scanning calorimetry and Fourier transform infrared spectroscopy (FTIR). The BPA is miscible with both PVAc and PVP based on the observed single T_g over the entire composition range. FTIR was used to study the hydrogen-bonding interaction between the hydroxyl group of BPA and the carbonyl group of PVAc and PVP at various compositions. Furthermore, the addition of BPA is able to enhance the miscibility of the immiscible PVAc/PVP binary blend and eventually transforms into miscible blend with single T_g, when a sufficiently quantity of the BPA is present due to the significant Δχ and the ΔK effect.     

Miscibility study of poly(vinyl chloride)/poly(methyl methacrylate‐co‐4‐vinylpyridine) by viscosimetry,DSC, and FTIR

The miscibility of the poly(vinyl chloride)/poly(methylmethacrylate) system were improved by introducing pyridine units into poly(methylmethacrylate) main. For this purpose, we have synthesized through a radical polymerization a series of methylmethacrylate‐co‐vinyl‐4‐pyridine copolymers of different compositions and carried out a comparative study by viscosimetry, differential scanning calorimetry, and Fourier transform infrared spectroscopic (FTIR) methods. The viscosimetric analysis using the Krigbaum‐Wall, K. K. Chee, and Compos approaches revealed that, the Poly(vinyl chloride)/poly(methylmethactylate‐co‐4‐vinylpyridine)(PVC/MMA4VP‐15) at 15 wt % of 4‐vinylpyridine systems in tetrahydrofuran are completely miscible in all proportions. The differential scanning calorimetry analysis confirmed the miscibility of these systems in all proportions by the appearance of only one glass transition temperature between those of the two pure constituents. The Kwei and Schneider approaches showed also the miscibility of this system, which is due to the specific interactions between the acidic hydrogen atom of PVC and the nitrogen of MMA4VP‐15. The use of FTIR method has confirmed the occurrence of this kind of interactions by broadening and shifting of the involved functional groups vibration bands. In this work, we have also carried out a preliminary test of sorption of THF aqueous solution by PVC and PVC/MMA4VP‐15 blend membranes. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Polymer electrolytes based on a ternary miscible blend of poly(ethylene oxide), poly(bisphenol A-co-epichlorohydrin) and poly(vinyl ethyl ether)

Ternary blends of poly(ethylene oxide) (PEO), poly(bisphenol A-co-epichlorohydrin) (PBE) and poly(vinyl ethyl ether) (PVEE) were obtained as films and characterized by differential scanning calorimetry (DSC) and vibrational spectroscopy (FTIR). From the DSC results, phase diagrams for the ternary blends were determined, where the variation of the viscoelastic phase extent as a function of the polymers composition was determined. The DSC results also indicated miscibility of the system, exhibiting only one glass transition temperature (T_g) and decrease in the crystallinity of the system, as well as decrease in the crystallinity of PEO present in the blends. Vibrational spectroscopy (FTIR) provided information on the intermolecular interactions between the pairs PBE/PEO and PBE/PVEE, via hydrogen bond interaction. From the FTIR analyses, molecular model systems of equilibrium among the interacting structures were proposed as a molecular basis for the miscibility of the system.Polymer electrolytes based on the ternary blend containing 60/25/15 (PEO/PBE/PVEE) mass percent and lithium perchlorate (LiClO₄) were obtained and characterized by DSC, FTIR, optical microscopy and electrochemical impedance spectroscopy (EIS). Solid electrolytes containing up to 10 wt% LiClO₄ exhibited a single-phase behavior, evidenced by the DSC results. For these electrolytes, FTIR spectra indicated the formation of polymer-ion complexes, in which the cation (Li⁺) acts favoring the polymer-polymer miscibility. Electrolytes containing LiClO₄ higher than 10 wt% exhibit a multiple phase behavior, in which a PEO-rich, salt-containing phase is present in equilibrium with PBE or PVEE-rich phases. Maximum ionic conductivity at room temperature, for the electrolyte containing 20 wt% LiClO₄, reached 4.23 × 10⁻³ Ω⁻¹ cm⁻¹, while all samples exhibited conductivity of approximately 10⁻¹ Ω⁻¹ cm⁻¹ at 80 °C.     

Miscibility and phase behavior in blends of poly(hydroxyether of bisphenol A) with poly(ethylene oxide-co-propylene oxide)

The miscibility of poly(hydroxyether of bisphenol A) (phenoxy) with a series of poly(ethylene oxide-co-propylene oxide) (EPO) has been studied. It was found that the critical copolymer composition for achieving miscibility with phenoxy around 60°C is about 22 mol % ethylene oxide (EO). Some blends undergo phase separation at elevated temperatures, but there is no maximum in the miscibility window. The mean-field approach has been used to describe this homopolymer/copolymer system. From the miscibility maps and the melting-point depression of the crystallizable component in the blends, the binary interaction energy densities, B_ij, have been calculated for all three pairs. The miscibility of phenoxy with EPO is considered to be caused mainly by the intermolecular hydrogen-bonding interactions between the hydroxyl groups of phenoxy and the ether oxygens of the EO units in the copolymers, while the intramolecular repulsion between EO and propylene oxide units in the copolymers contributes relatively little to the miscibility. © 1993 John Wiley & Sons, Inc.     

Self-assembly of an A-B diblock copolymer blended with a C homopolymer and a C-D diblock copolymer through hydrogen bonding interaction

In this study, we investigated the miscibility, phase behavior, and self-assembled nanostructures formed from the immiscible crystalline-amorphous diblock copolymer poly(?-caprolactone-b-4-vinyl pyridine) (PCL-b-P4VP, A-B) when blended with the homopolymer poly(vinyl phenol) (PVPh, C) and the diblock copolymer poly(vinyl phenol-b-styrene) (PVPh-b-PS, C-D). Long-range-ordered microphase separation was difficult to achieve in the PCL-b-P4VP/PVPh (A-B/C) blend system because PVPh interacted with both the P4VP and PCL blocks simultaneously through hydrogen bonding interactions. In contrast, we observed sharp, multiple orders of diffraction in the SAXS profiles of the PCL-b-P4VP/PVPh-b-PS (A-B/C-D) blend system, indicating that perfect microphase separation occurred because the incorporation of the PS block induced the PVPh block to hydrogen bond preferentially with the P4VP block. This simple A-B/C-D (PCL-b-P4VP/PVPh-b-PS) diblock copolymer mixture exhibited self-assembly behavior (a three-lamella phase) similar to that of a corresponding ABC triblock copolymer.     

Binary poly(cyclohexyl methacrylate)/poly(styrene-co-vinyl phenol) blends: Comparisons of phase behaviour predictions using a single and a double interassociation model

The miscibility in blends of poly(cyclohexyl methacrylate) (PCHMA) with poly(4-vinyl phenol) (PVPh) and with copolymers containing vinyl phenol and styrene units (PSVPh) has been examined by Fourier transform infrared spectroscopy. The phase behaviour of the PCHMA/PSVPh system was predicted by means of association model of Painter and Coleman (PCAM) with a single interassociaton equilibrium constant (K_A) as well as by means of a new double interassociation model (D.I.M). The second interassociation equilibrium includes the weaker interaction between carbonyl and phenyl groups of CHMA and styrene (S) repeat units, respectively. In order to quantify the effect of free volume on miscibility, different contributions to free energy of mixing have been calculated. The predicted miscibility map did not change appreciably when compressibility effects were considered. On the other hand, by taking into account the second weaker interaction, better agreement between experimental and predicted miscibility maps is found for binary PCHMA/PSVPh blends. Finally, the D.I.M. has been extended to the case of ternary PCHMA/PS/PVPh blends.