FTIR Investigation of ion-dipole interaction in styrene ionomer/poly(ethylene oxide) blends

Fourier-transform infrared (FTIR) spectroscopy was used to examine specific interactions contributing to the partial miscibility in blends of styrene-sodium methacrylate copolymer (S-NaMA) and poly(ethylene oxide) (PEO). From the shifts of carboxylatelon and ether group stretching bands, an important specific interaction was found involving ion-dipole bonding between the ionic group in styrene ionomer and the ether group in PEO. The asymmetric stretching vibration frequency of the carboxylate ion group increases as the fractional amount of PEO in the blend is increased, while the symmetric stretching frequency is decreased. The transition value of the fraction of PEO, above which both vibration frequencies of the carboxylate ion mentioned above remained almost unchanged, increases as the concentration of ionic groups in ionomer is increased. The ether group stretching band shifts to higher frequencies as the PEO content in the ionomer/PEO blend is increased. From the differential scanning calorimetry (DSC) and FTIR studies, we find that the iondipole interaction is the important mechanism that determines the miscibility of S-NaMA/PEO blends. © 1994 John Wiley & Sons, Inc.     

Novel composite polymer electrolytes based on poly(ether-urethane) network polymer and modified montmorillonite

Novel composite solid polymer electrolytes (CSPEs) and composite gel polymer electrolytes (CGPEs) have been prepared. CSPE consists of poly(ether-urethane) network polymer, which is superior to poly(ethylene oxide) in mechanical stability due to its cross-linked structure, modified montmorillonite (MMMT) and LiClO₄, and CGPE with good mechanical strength comprises of the CSPE and LiClO₄–PC (propylene carbonate) solution. The ionic conductivity can be enhanced after the addition of MMMT, and CGPE exhibits ionic conductivity in the order of 10⁻³ S/cm at room temperature. The temperature dependence of the ionic conductivity of the CSPE follows the Vogel–Tamman–Fulcher (VTF) equation. The effects of MMMT on the interactions in these systems and the possible conduction mechanisms are also discussed.     

以离子-离子相互作用增强共混相容性Ⅰ.聚苯醚离聚体/聚(苯乙烯-乙烯吡啶)共混体系

本文从溶液行为和固体热行为对聚（2，6-二甲基1，4-苯醚）（PPO）离聚体（磺化聚苯醚或接化聚苯醚）／聚（苯乙烯-4-乙烯吡啶）（PS－VP）共混物进行了研究。DSC研究表明磺化度为7．7％mol的SPPO／PS－VP和羧化度为15％molCPPO炉S－VP在整个组成范围都是相容的。溶液行为研究表明，与对应的PPO／PS－VP共混物相比，这两个系列的共混物都表现出较高的比浓粘度。这是由于聚苯醚离聚体上的酸基发生质子转移，两组分间强烈的离子-离子相互作用导致分子间的络合，从而使比浓粘度的提高，也正是这种离子-离子相互作用使得这两对共混物完全相容。     

Effect of styrene-4-vinyl pyridine diblock copolymer on morphological,thermal, and mechanical properties of poly(2,6-dimethyl-1,4-phenylene ether)/polyethylene ionomer blends

The compatibilizing effects of a styrene-4-vinyl pyridine diblock copolymer on the properties of immiscible poly(2,6-dimethyl-1,4-phenylene ether) (PPE)/polyethylene ionomer (Surlyn) blends are investigated by examining the phase morphology and the thermal and mechanical properties. The block copolymer is synthesized by sequential anionic polymerization at ?78°C and melt-mixed with PPE and Surlyn at 290°C. When a small amount of block copolymer is present, the domain size of the dispersed phase becomes smaller. The tensile strength and elongation at break increase with addition of the block copolymer for PPE-rich matrix blends, whereas the tensile strength increases but the elongation at break decreases for Surlyn-rich matrix blends. These effects are interpreted in terms of the interfacial activity and the reinforcing effect of the block copolymer. From the experimental results, it is concluded that the block copolymer plays a role as an effective compatibilizer for PPE/Surlyn blends. © 1994 John Wiley & Sons, Inc.     

Heat of mixing in polymer blends based on poly(vinyl acetate)

Knowledge of the heat of mixing is very important in order to evaluate the interaction parameter, according to the Patterson theory. In this work we illustrate the results regarding some polymer blends, based on poly(vinyl acetate) and some polyacrylates with different substituent groups. In this way it is possible to understand the effect of the lateral group hindrance, as it will be illustrated in the paper.     

Plasticization of a poly(ethyl acrylate) ionomer by an alkyl aniline

The plasticization by 4-decylaniline (4DA) of a microphase-separated poly(ethyl acrylate) ionomer containing sodium carboxylate groups is examined. Dynamic mechanical thermal analysis, supplemented by differential scanning calorimetry, shows that the matrix and cluster glass transitions (T_g's) in the ionomer are both depressed by ca. 1°C/wt % 4DA; this, in turn, is similar to the T_g depression in the blend of the parent poly(ethyl acrylate) (PEA) with 4DA. There is no evidence of 4DA crystallinity in the blend. Small-angle x-ray scattering (SAXS) measurements show that the ionomer peak increases in intensity and decreases in scattering angle with increasing concentration of 4DA in the blend; the corresponding Bragg spacing, initially at 2.3 nm, increases by ca. 0.04 nm/wt % 4DA. These results, supported by preliminary spectroscopic measurements, are attributed to hydrogen bonding interactions between the amine groups of 4DA and the ester groups in PEA and the ionomer, rendering the blend miscible. It is argued that the uniform distribution of 4DA throughout the material plasticizes both phases of the ionomer by adding free volume; this also accounts for the increase in the characteristic spacing detected by SAXS.     

Effect of PEO‐PPO‐PEO copolymer on the mechanical and thermal properties and morphological behavior of biodegradable poly (L‐lactic acid) (PLLA) and poly (butylene succinate‐co‐L‐lactate) (PBSL) blends

A blend of two biodegradable and semi‐crystalline polymers, poly (L‐lactic acid) (PLLA; 70 wt%) and poly (butylene succinate‐co‐L‐lactate) (PBSL; 30 wt%), was prepared in the presence of various polyethylene oxide‐polypropylene oxide‐polyethylene oxide (PEO‐PPO‐PEO) triblock copolymer contents (0.5, 1, 2 wt%). Mechanical, thermal properties, and Fourier transform infrared (FTIR) analysis of the blends were investigated. It was found that the addition of copolymer to PLLA/PBSL improved the fracture toughness of the blends as shown by mode I fracture energies. It was supported by morphological analysis where the brittle deformation behavior of PLLA changed to ductile deformation with the presence of elongated fibril structure in the blend with copolymer system. The glass transition temperature (T_g), melting temperature (T_m) of PLLA, and PBSL shift‐closed together indicated that some compatibility exists in the blends. In short, PEO‐PPO‐PEO could be used as compatibilizer to improve the toughness and compatibility of the PLLA/PBSL blends. Copyright © 2010 John Wiley & Sons, Ltd.     

Novel composite polymer electrolytes based on poly(ether-urethane) network polymer and fumed silicas

Novel composite solid polymer electrolytes (CSPEs) and composite gel polymer electrolytes (CGPEs) have been prepared. CSPE consists of poly(ether-urethane) network polymer (PUN), fumed silicas and LiClO₄. The ionic conductivity of CSPEs can be enhanced nearly 20 times in comparison with the plain system without the addition of fumed silicas and can be above 1×10⁻⁵ S/cm at room temperature. The effects of both kinds of fumed silicas, viz. uSiO₂ with hydrophilic groups at the surface and mSiO₂ with hydrophobic groups at the surface on ionic conductivity were investigated. CGPE comprising of the CSPE and LiClO₄–PC solution with good mechanical strength exhibits ionic conductivity in the order of 10⁻³ S/cm at room temperature and above 3×10⁻⁴ S/cm at low temperature −40 °C.     

Poly[(R)‐3‐hydroxybutyrate)]/poly(styrene) blends compatibilized with the relevant block copolymer

A novel triblock copolymer PS–PHB–PS based on the microbial polyester Poly[(R)‐3‐hydroxybutyrate)] (PHB) and poly(styrene) (PS) was prepared to be used as compatibilizer for the corresponding PHB/PS blends. It was prepared in a three‐step procedure consisting of (i) transesterification reaction between ethylene glycol and a high‐molecular‐weight PHB, (ii) synthesis of bromo‐terminated PHB macroinitiator, and (iii) atom transfer radical polymerization polymerization of styrene initiated by the PHB‐based macroinitiator. Fourier transform infrared, gel permeation chromatography, ¹H‐, and ¹³C‐NMR spectroscopies were used to determine the molecular structure and/or end‐group functionalities at each step of the procedure. Although thermogravimetric analysis showed that the block copolymer underwent a stepwise thermal degradation and had better thermal stability than their respective homopolymers, differential scanning calorimetry displayed that the PHB block in the copolymer could not crystallize, and thus generating a total amorphous structure. Atomic force microscopy images indicated that the block copolymer was phase segregated in a well‐defined morphological structure with nanodomain size of ～40 nm. Contact angle measurements proved that the wettability properties of the block copolymer were in between those of the PHB and PS homopolymers. Blends analyzed for their morphology and thermal properties showed good miscibility and had well‐defined morphological features. Polymer blends exhibited lower crystallinity and decreased stiffness which was proportional to the amount of compatibilizer content in the blends. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Viscometric behaviour of polymer blends based on poly (vinylidene fluoride)

The viscosity behaviour of dilute dimethylformamide solutions of poly(vinylidene fluoride)-poly (methyl methacrylate) and poly(vinylidene fluoride)-polystyrene has been studied at 25°C. The polymer concentration ranges are such that neither phase separation nor microgel formation occurs, although we are very close to theta conditions. The intrinsic viscosity and viscosity interaction parameter of the ternary mixtures have been calculated. The estimation of the compatibility of the above polymer pairs has been studied based on: a) specific viscosities; b) viscosity interaction parameters, according to Krigbaum and Wall formalism, and c) viscosity interaction parameters of a system formed by a dilute probe polymer in the presence of a matrix polymer and a small molecule solvent.     

Synthesis of a random copolymer and its compatibility for thermotropic liquid crystalline polymer/poly(ether ether ketone) blends

A random copolymer (RCP) containing poly(ether ether ketone) (PEEK) and thermotropic liquid crystalline polymer (TLCP) segments was synthesized. Its chemical structure and liquid crystalline properties were characterized by FT‐IR, differential scanning calorimetry (DSC) and polar light microscopy (PLM) respectively. A single glass transition temperature (T_g) at 134.0°C, a melting temperature (T_m) at 282.0°C and a temperature of ignition (T_i) at 331.3°C can be observed. Blends of PEEK and TLCP with and without RCP as compatibilizer were prepared by extrusion and the effect of RCP on the thermal properties, dynamic mechanical properties, morphology and static tensile mechanical properties of blends was investigated by means of DSC, dynamic mechanical analysis (DMA), scanning electron microscopy (SEM), etc. Dynamic mechanical measurements indicated that there appeared to be only a single tan δ peak resulting from the glass transition of the PEEK‐rich phase and the T_g value shifted towards higher temperature due to the presence of compatibilizer, as suggested partial compatibility. Morphological investigations showed that the addition of RCP to binary blends reduced the dispersed phase size and improved the interfacial adhesion between the two phases. The ternary compatibilized blends showed enhanced tensile modulus compared to their binary blends without RCP. The strain at break decreased for the ternary blends due to embrittlement of the matrix by the incorporation of some RCP to the matrix phase. Copyright © 2007 John Wiley & Sons, Ltd.     

MMTCA recognition by molecular imprinting in interpenetrating polymer network hydrogels based on poly(acrylic acid) and poly(vinyl alcohol)

A novel IPN hydrogel designed to recognize MMTCA is prepared by applying the molecular-imprinting method. The IPN is characterized by FT-IR, DSC, and SEM. Langmuir analysis shows that an equal class of adsorption is formed in the hydrogel. The adsorption equilibrium constant and the maximum adsorption capacity are evaluated, and the effect of the pH on MMTCA adsorption is discussed. The selectivity of the imprinted polymer for MMTCA is studied in aqueous solutions of MMTCA/aspirin/riboflavin. The results suggest that the MMTCA-imprinted polymer shows superior selectivity for MMTCA as compared to riboflavin and aspirin. The reproducibility of the imprinted polymer to MMTCA is also studied.     

Compatibilizing effect of a graft copolymer on bacterial poly(3‐hydroxybutyrate)/poly(methyl methacrylate) blends

Blends of isotactic (natural) poly(3‐hydroxybutyrate) (PHB) and poly(methyl methacrylate) (PMMA) are partially miscible, and PHB in excess of 20 wt % segregates as a partially crystalline pure phase. Copolymers containing atactic PHB chains grafted onto a PMMA backbone are used to compatibilize phase‐separated PHB/PMMA blends. Two poly(methyl methacrylate‐g‐hydroxybutyrate) [P(MMA‐g‐HB)] copolymers with different grafting densities and the same length of the grafted chain have been investigated. The copolymer with higher grafting density, containing 67 mol % hydroxybutyrate units, has a beneficial effect on the mechanical properties of PHB/PMMA blends with 30–50% PHB content, which show a remarkable increase in ductility. The main effect of copolymer addition is the inhibition of PHB crystallization. No compatibilizing effect on PHB/PMMA blends with PHB contents higher than 50% is observed with various amounts of P(MMA‐g‐HB) copolymer. In these blends, the graft copolymer is not able to prevent PHB crystallization, and the ternary PHB/PMMA/P(MMA‐g‐HB) blends remain crystalline and brittle. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1390–1399, 2002     

On the morphological behavior of ABC miktoarm stars containing poly(cis 1,4-isoprene), poly(styrene), and poly(2-vinylpyridine)

Fundamental understanding of microphase separation in ABC miktoarm copolymers is vital to access a plethora of nonconventional morphologies. Miktoarm stars based on poly(cis 1,4-isoprene) (I), poly(styrene) (S), and poly(2-vinylpyridine) (V) are model systems, which allow systematic studies of the effects of composition, chemical microstructure, and temperature on the thermodynamics of microphase separation. Eleven ISV-x (I:S:V = 1:1:x, v:v:v) miktoarm copolymers were synthesized by anionic polymerization affording well-defined copolymers with a variable V arm. Equilibrium bulk morphologies of all samples, as evidenced by small-angle X-ray scattering, transmission electron microscopy (TEM), and self-consistent field theory, showed a systematic transition from lamellae (x ≈ 0–0.2) to [8.8.4] tiling (x ≈ 0.6–0.9) to cylinders in undulating lamellae (x ≈ 2–4) and, finally, to hexagonally packed core–shell cylinders (x ≈ 5–8). Chemical microstructure of the I arm [poly(cis 1,4-isoprene)] versus poly(3,4-isoprene) is shown to play important role in affecting morphological behavior. To reconcile differences between ISV-x star morphologies reported in the literature and those reported herein, even for the same composition, effects of the microstructure of I arm on the Flory–Huggins parameter between I and V arms were taken into account in a qualitative manner. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 1491–1504     

New super‐tough poly(butylene terephthalate) materials based on compatibilized blends with metallocenic poly(ethylene‐octene) copolymer

New super‐tough poly(butylene terephthalate) (PBT)/poly(ethylene‐octene) copolymer (PEO) blends containing 2 wt% poly(ethylene‐co‐glycidyl methacrylate) (EGMA) as a compatibilizer were obtained by extrusion and injection molding. The blends comprised of an amorphous PBT‐rich phase with some miscibilized EGMA, a pure PEO amorphous phase, and a crystalline PBT phase that was not influenced by the presence of either PEO or EGMA. The blends showed a fine particle size up to 20 wt% PEO content. Super‐tough blends were obtained with PEO contents equal to or higher than 10%. The maximum toughness was very high (above 710 J/m) and was attained with 20% PEO without chemical modification of the commercial components used. Copyright © 2003 John Wiley & Sons, Ltd.     

Compatible and tearing properties of poly(lactic acid)/poly(ethylene glutaric‐co‐terephthalate) copolyester blends

Fourier transform infrared and nuclear magnetic resonance results suggest that the carboxylic acid groups of poly(lactic acid) (PLA) molecules react with the hydroxyl groups of FePol (FP) molecules during the melt‐blending of PLA_xFP_y specimens. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) experiments of PLA and PLA/FP specimens suggest that only small amounts of poor PLA and/or FP crystals are present in their corresponding melt crystallized specimens. In fact, the percentage crystallinity, peak melting temperature, and onset re‐crystallization temperature values of PLA/FP specimens reduce gradually as their FP contents increase. However, the glass transition temperatures of PLA molecules found by DSC and DMA reduce to a minimum value as the FP contents of PLA_xFP_y specimens reach 6 wt %. Further DMA and morphological analysis of PLA/FP specimens reveal that FP molecules are compatible with PLA molecules at FP contents equal to or less than 6 wt %, as no distinguished phase‐separated FP droplets and tan δ transitions were found on fracture surfaces and tan δ curves of PLA/FP specimens, respectively. In contrast to PLA, the FP specimen exhibits highly deformable and tearing properties. After blending proper amounts of FP in PLA, the inherent brittle deformation and poor tearing behavior of PLA were successfully improved. Possible reasons accounting for these interesting crystallization, compatible and tearing properties of PLA/FP specimens are proposed. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 913–920, 2010     

Charge-mosaic membrane from gamma-irradiated poly(styrene-butadiene-4-vinylpyridine) triblock copolymer

Poly(styrene-butadiene-4-vinylpyridine) triblock copolymers were prepared from styrene (S), butadiene (B), and 4-vinylpyridine (P) by sequential anionic polymerization with n-butyllithium as initiator and benzene as solvent. The triblock copolymer was characterizated by gel-permeation chromatography (GPC), transmission electron microscopy (TEM), and viscoelastic spectrometry. Films of the triblock copolymer cast from solution in mixtures of chloroform and n-butyraldehyde were subjected to gamma-ray irradiation to form cross-linked networks, Cationic and anionic groups were introduced by sulfonation and quater-nization to obtain charge-mosaic membranes. The resulting membrane had substantial cation-exchange and anion-exchange capacities. The membranes were very permeable to electrolyte (J_KCI = 2.10×10^?8 mol/cm² s). © 1993 John Wiley & Sons, Inc.