Preparation of electrorheological active ionomers from poly(2‐hydroxyethyl methacrylate)‐co‐poly(4‐vinyl pyridine)

In this study, synthesis, characterization, partial hydrolysis, and salt formation of poly(2‐hydroxyethyl methacrylate)‐co‐poly(4‐vinyl pyridine), (poly(HEMA)‐co‐poly‐(4‐VP)) copolymers were investigated. The copolymers were synthesized by free radical polymerization using K₂S₂O₈ as an initiator. By varying the monomer/initiator ratio, chain lengths of the copolymers were changed. The copolymers were characterized by gel permeation chromatography (GPC), viscosity measurements, ¹H and ¹³C NMR and FTIR spectroscopies, elemental analysis, and end group analysis methods. The copolymers were partially hydrolyzed by p‐toluene sulfonic acid monohydrate (PTSA·H₂O) and washed with LiOH_(aq) solution to prepare electrorheological (ER) active ionomers, poly(Li‐HEMA)‐co‐poly(4‐VP). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3540–3548, 2006     

Poly(N‐isopropylacrylamide‐co‐hydroxyethyl methacrylate) graft copolymers and their application as carriers for drug delivery system

Poly(N‐isopropylacrylamide‐co‐hydroxyethyl methacrylate) [P(NIPAM‐co‐HEMA)] copolymer was synthesized by controlled radical polymerization from respective N‐isopropylacrylamide (NIPAM) and hydroxyethyl methacrylate (HEMA) monomers with a predetermined ratio. To prepare the thermosensitive and biodegradable nanoparticles, new thermosensitive graft copolymer, poly(L ‐lactide)‐graft‐poly(N‐isoporylacrylamide‐co‐hydroxyethyl methacrylate) [PLLA‐g‐P(NIPAM‐co‐HEMA)], with the lower critical solution temperature (LCST) near the normal body temperature, was synthesized by ring opening polymerization of L ‐lactide in the presence of P(NIPAM‐co‐HEMA). The amphiphilic property of the graft copolymers was formed by the grafting of the PLLA hydrophobic chains onto the PNIPAM based hydrophilic backbone. Therefore, the graft copolymers can self‐assemble into uniformly spherical micelles ò about 150–240 nm in diameter as observed by the field emission scanning electron microscope and dynamic light scattering. Dexamethasone can be loaded into these nanostructures during dialysis with a relative high loading capacity and its in vitro release depends on temperature. Above the LCST, most of the drugs were released from the drug‐loaded micelles, whereas a large amount of drugs still remains in the micelles after 48 h below the LCST. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Poly(ethylene‐co‐vinyl acetate)‐graft‐poly(methyl methacrylate) (EVA‐graft‐PMMA) as a modifier of epoxy resins

Conventional approaches to toughen thermosets are: (1) the polymerization‐induced phase separation of a rubber or a thermoplastic, or (2) the use of a dispersion of preformed particles in the initial formulation. In the present study it is shown that it is possible to combine both techniques by using graft copolymers with one of the blocks being initially immiscible and the other that phase separates during polymerization. This is illustrated by the use of poly(ethylene‐co‐vinyl acetate)‐graft‐poly(methyl methacrylate) (EVA‐graft‐PMMA) as modifier of an epoxy resin. EVA is initially immiscible and PMMA phase separates during polymerization. Blends of an epoxy monomer based on diglycidylether of bisphenol A (DGEBA, 100 parts by weight), piperidine (5 parts by weight), and PMMA (5 parts by weight), showed the typical polymerization‐induced phase separation of PMMA‐rich domains before gelation of the epoxy network. Replacing PMMA by EVA‐graft‐PMMA (5 parts by weight), yielded stable dispersions of EVA blocks, favoured by the initial solubility of PMMA blocks. Phase separation of PMMA blocks in the course of polymerization led to a dispersion of in situ generated biphasic particles (plausibly composed of EVA cores surrounded by PMMA shells), with average diameters varying from 0.3 to 0.6 µm with the cure temperature. This procedure may be used to generate stable dispersions of biphasic particles for toughening purposes. © 2002 Society of Chemical Industry     

Poly(4‐vinyl pyridine)‐grafted graphene oxide for drug delivery and antimicrobial applications

Graphene oxide (GO) was covalently functionalized with poly(4‐vinyl pyridine) (P4VP) by atom transfer radical polymerization for drug delivery and antimicrobial applications. The physiochemical properties, chemical structure, composition and morphology of the P4VP‐functionalized GO (GO‐P4VP) were studied. Simple physisorption of a cancer drug, camptothecin (CPT), via π ? π stacking and/or hydrophobic interactions on the GO‐P4VP was tested for drug loading and its release by altering the pH. The GO‐P4VP has low cytotoxicity, and the CPT‐loaded GO‐P4VP exhibited a high potency for killing cancer cells in vitro. Prominent antimicrobial properties against Escherichia coli and Staphylococcus aureus were also observed. Thus, the GO‐P4VP can be utilized as a drug delivery vector with high biocompatibility, solubility and stability in physiological solutions, a suitable payload capacity and excellent bacterial toxicity. Owing to its small size, low cost, large specific area, ready scalability and useful non‐covalent interactions, GO‐P4VP is a novel material for biomedical, industrial and environmental applications. © 2015 Society of Chemical Industry     

Synthesis and reactive features of a terpolymer: Poly(N‐vinyl‐2‐pyrrolidone‐co‐vinyl acetate‐co‐glycidyl methacrylate)

A polyvinyl pyrrolidone terpolymer system is described that can be chemically cross‐linked at moderate, 70–100°C, temperatures. The system has significant potential for development of durable long‐lasting pyrrolidone coatings in a wide range of applications, particularly in water filtration membrane construction where leaching is an unresolved, serious problem. The synthesis of the terpolymer, poly(N‐vinyl‐2‐pyrrolidone‐co‐vinyl acetate‐co‐glycidyl methacrylate), by free radical polymerization is described. The reactive features of this terpolymer are presented in the context of acidic anhydride curing. In a polar aprotic solvent, the terpolymer is reacted with poly(methyl vinyl ether‐co‐maleic acid) and cured thermally. Key aspects of the terpolymer synthesis and the acid anhydride cross‐linking reaction using DSC, rheology, FTIR, and a small molecule model system to study the cross‐linking chemistry are presented. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Specific interactions in poly(styrene‐co‐2‐hydroxyethyl acrylate)/poly(styrene‐co‐N,N‐dimethylacrylamide) systems

Amphiphilic copolymers of poly(styrene‐co‐2‐hydroxyethyl acrylate) (SHEA) and poly(styrene‐co‐N, N‐dimethylacrylamide) (SAD) of different compositions were prepared by free radical copolymerization and characterized by different techniques. Depending on the nature of the solvent and the densities of interacting species incorporated within the polystyrene matrices, novel materials as blends or interpolymer complexes with properties different from those of their constituents were elaborated when these copolymers are mixed together. The specific interpolymer interactions of hydrogen bonding type and the phase behavior of the elaborated materials were investigated by differential scanning calorimetry (DSC) and Fourier transform infra red spectroscopy (FTIR). The specific interactions of hydrogen bonding type that occurred within the SHEA and within their blends with the SAD were evidenced by FTIR qualitatively by the appearance of a new band at 1626 cm^?1 and quantitatively using appropriate spectral curve fitting in the carbonyl and amide regions. The variation of the glass transition temperature with the blend composition behaved differently with the densities of interacting species. The thermal degradation behavior of the materials was studied by thermogravimetry. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Poly(2‐hydroxyethyl methacrylate‐co‐ethylene dimethacrylate) as a mouse embryonic stem cells support

A series of swellable ethylene dimethacrylate‐crosslinked poly(2‐hydroxyethyl methacrylate) (PHEMA) sheets of homogeneous (nonporous) structure or with different degrees of swelling and porosities was produced by bulk polymerization in either the absence or the presence of various diluents (porogens). Calculations performed by use of the solubility parameter δ of the reaction components indicate that the solvation conditions of the polymerization system change, depending on the solvating power of the diluent, which thus controls the porosity. Pore volume also seemed to be sensitive to the presence of the linear polymer diluent. Polystyrene (PS) showed, compared with poly(methyl methacrylate) (PMMA), a higher precipitating ability to form porous PHEMA sheets with an increased pore size because of its higher noncompatibility with newly formed crosslinked PHEMA. Given that PHEMA hydrogel is well known for its biocompatibility, it was used here as a potential carrier of cells in transplantation therapies. Attachment and growth of mouse embryonic stem (ES) cells on gelatin‐coated transparent PHEMA hydrogel substrates were examined. Two days after plating, survival and morphology of ES cells were largely similar on both PHEMA hydrogel sheets and in petri dishes as controls. This suggests that PHEMA hydrogels are likely candidates for application in transplantation therapies involving ES cells. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 425–432, 2003     

Preparation and characterization of cyhalothrin‐loaded poly(2‐hydroxyethyl methacrylate)‐co‐polylactide (PHEMA‐co‐PLA) ultrafine particles

Poly(2‐hydroxyethyl methacrylate)‐co‐polylactide (PHEMA‐co‐PLA) and its corresponding cyhalothrin‐loaded ultrafine particles were successfully synthesized and prepared, respectively. The chemical structures of the copolymers have been confirmed by Fourier transform infrared spectroscopy (FTIR), ¹H‐nuclear magnetic resonance (¹H‐NMR), ¹³C‐nuclear magnetic resonance (¹³C‐NMR), and thermogravimetric analysis (TGA). Furthermore, the particle size, the cyhalothrin loading content (LC), and the cyhalothrin release behavior were investigated. PHEMA‐co‐PLA proved to be a good material for the preparation of ultrafine particles for lipophilic pesticide delivery. The developed cyhalothrin‐loaded PHEMA‐co‐PLA ultrafine particles showed good dispersity in water and sustained release behavior. In addition, it is easy to be prepared by both nanoprecipitation method and emulsion/solvent evaporation method. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation of collagen‐immobilized poly(ethylene glycol)/poly(2‐hydroxyethyl methacrylate) interpenetrating network hydrogels for potential application of artificial cornea

To enhance the mechanical strength of poly(ethylene glycol)(PEG) gels and to provide functional groups for surface modification, we prepared interpenetrating (IPN) hydrogels by incorporating poly(2‐hydroxyethyl methacrylate)(PHEMA) inside PEG hydrogels. Formation of IPN hydrogels was confirmed by measuring the weight percent gain of the hydrogels after incorporation of PHEMA, as well as by ATR/FTIR analysis. Synthesis of IPN hydrogels with a high PHEMA content resulted in optically transparent and extensively crosslinked hydrogels with a lower water content and a 6 ～ 8‐fold improvement in mechanical properties than PEG hydrogels. Incorporation of less than 90 wt % PHEMA resulted in opaque hydrogels due to phase separation between water and PHEMA. To overcome the poor cell adhesion properties of the IPN hydrogels, collagen was covalently grafted to the surface of IPN hydrogels via carbamate linkages to hydroxyl groups in PHEMA. Resultant IPN hydrogels were proven to be noncytotoxic and cell adhesion study revealed that collagen immobilization resulted in a significant improvement of cell adhesion and spreading on the IPN hydrogel surfaces. The resultant IPN hydrogels were noncytotoxic, and a cell adhesion study revealed that collagen immobilization improved cell adhesion and spreading on the IPN hydrogel surfaces significantly. These results indicate that PEG/PHEMA IPN hydrogels are highly promising biomaterials that can be used in artificial corneas and a variety of other load‐bearing tissue engineering applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and characterization of poly[4‐(2‐thiazolylazo)phenyl methacrylate]‐co‐poly(methyl methacrylate)

A new methacrylic monomer, 4‐(2‐thiazolylazo)phenylmethacrylate (TPMA) was synthesized. Copolymerization of the monomer with methyl methacrylate (MMA) was carried out by free radical polymerization in THF solution at 70 ± 0.5°C, using azobisisobutyronitrile (AIBN) as an initiator. The monomer TPMA and the copolymer poly(TPMA‐co‐MMA) were characterized by Fourier transform infrared (FTIR), ¹H nuclear magnetic resonance (NMR), and elemental analysis methods. The polydispersity index of the copolymer was determined using gel permeation chromatography (GPC). Thermogravimetric analysis (TGA) of the copolymer performed in nitrogen revealed that the copolymer was stable to 270°C. The glass transition temperature (T_g) of the copolymer was higher than that of PMMA. The copolymer with a pendent aromatic heterocyclic group can be dissolved in common organic solvents and shows a good film‐forming ability. Both the monomer TPMA and the copolymer poly (TPMA‐co‐MMA) have bright colors: orange and yellow, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2152–2157, 2007     

DNA adsorption on a poly‐L‐lysine‐immobilized poly(2‐hydroxyethyl methacrylate) membrane

The DNA adsorption properties of poly‐L ‐lysine‐immobilized poly(2‐hydroxyethyl methacrylate) (pHEMA) membrane were investigated. The pHEMA membrane was prepared by UV‐initiated photopolymerization and activated with epichlorohydrin. Poly‐L ‐lysine was then immobilized on the activated pHEMA membrane by covalent bonding, via a direct chemical reaction between the amino group of poly‐L ‐lysine and the epoxy group of pHEMA. The poly‐L ‐lysine content of the membrane was determined as 1537 mg m^?2. The poly‐L ‐lysine‐immobilized membrane was utilized as an adsorbent in DNA adsorption experiments. The maximum adsorption of DNA on the poly‐L ‐lysine‐immobilized pHEMA membrane was observed at 4 °C from phosphate‐buffered salt solution (pH 7.4, 0.1 M; NaCl 0.5 M) containing different amounts of DNA. The non‐specific adsorption of DNA on the plain pHEMA membrane was low (about 263 mg m^?2). Higher DNA adsorption values (up to 5849 mg m^?2) were obtained in which the poly‐L ‐lysine‐immobilized pHEMA membrane was used. Copyright © 2003 Society of Chemical Industry     

Shape memory properties and unusual optical behaviour of an interpenetrating network of poly(ethylene oxide) and poly(2‐hydroxyethyl methacrylate)

An interpenetrating polymer network (IPN) with shape memory properties was prepared by using poly(2‐hydroxyethyl methacrylate) (PHEMA) and poly(ethylene oxide) (PEO). PHEMA acts as a fixed phase and PEO as a switching phase. The switching action of PEO is due to the reversible process of melting and crystallization. It was observed that the shape recovery of the IPN increases with increasing crosslinker concentration up to an optimum value and decreases thereafter. In addition to the shape memory property, the IPNs show a reversible change in optical properties from translucent to opaque. The change in optical properties is quite different from that observed in a semicrystalline polymer system where the transparency increases as a result of the melting of crystals. This behaviour of the IPN is explained in terms of H‐bonding of PEO with PHEMA. Fourier transform infrared spectroscopy was used to study the H‐bonding between PEO and PHEMA. © 2019 Society of Chemical Industry     

Effect of tacticity of poly(methyl methacrylate) on the miscibility with poly(styrene‐co‐acrylonitrile)

Isotactic, atactic, and syndiotactic poly(methyl methacrylates) (PMMAs) (designated as iPMMA, aPMMA, and sPMMA) with approximately the same molecular weight were mixed separately with poly(styrene‐co‐acrylonitrile) (abbreviated as PSAN) containing 25 wt % of acrylonitrile in tetrahydrofuran to make three polymer blend systems. Differential scanning calorimetry (DSC) was used to study the miscibility of these blends. The results showed that the tacticity of PMMA has a definite impact on its miscibility with PSAN. The aPMMA/PSAN and sPMMA/PSAN blends were found to be miscible because all the prepared films were transparent and showed composition dependent glass transition temperatures (T_gs). The glass transition temperatures of the two miscible blends were fitted well by the Fox equation, and no broadening of the glass transition regions was observed. The iPMMA/PSAN blends were found to be immiscible, because most of the cast films were translucent and had two glass transition temperatures. Through the use of a simple binary interaction model, the following comments can be drawn. The isotactic MMA segments seemed to interact differently with styrene and with acrylonitrile segments from atactic or syndiotactic MMA segments. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2894–2899, 1999     

Rheological properties of homogeneous and heterogeneous poly(2‐hydroxyethyl methacrylate) hydrogels

The swelling and rheological behaviour of hydrogels of morphology varying from non‐porous to highly porous was investigated. The hydrogels were prepared by redox free radical copolymerization of 2‐hydroxyethyl methacrylate with 0.1 to 5 mol% of di(ethylene glycol) dimethacrylate in the presence of water varying from 40 to 80 wt%. Various compositions led to clear, turbid or macroporous gels. The morphology of the gels was characterized using optical microscopy and cryoscan electron microscopy. The oscillatory shear and creep of swollen gels revealed that there was a pronounced difference between homogeneous or microheterogeneous and macroporous gels with communicating pores. The achievement of optimum conditions for the correct determination of shear modulus was also analysed. Copyright © 2011 Society of Chemical Industry     

Modification of Nafion membrane using poly(4‐vinyl pyridine) for direct methanol fuel cell

Perfluorinated membrane such as Nafion (from Du‐Pont) has been used as a polymer electrolyte membrane. Nafion 117 membrane, which was usually used as the electrolyte membrane for the polymer electrolyte membrane fuel cell (PEMFC), was modified by using poly(4‐vinyl pyridine) (P4VP) to reduce the methanol crossover, which cause fuel losses and lower power efficiency, by the formation of an ionic crosslink structure (sulfonic acid‐pyridine complex) on the Nafion 117 surface. Nafion film was immersed in P4VP/N‐methyl pyrrolidone (NMP) solution. P4VP weight percent of modified membrane was controlled by changing the concentration of P4VP/NMP solution and the dipping time. P4VP weight percent increased with increasing concentration of dipping solution and dipping time. The thickness of the P4VP layer increased with increasing concentration of dipping solution and dipping time when the concentration of the dipping solution was low. At high P4VP concentration, the thickness of the P4VP layer was almost constant owing to the formation of acid–base complex which interrupted the penetration of P4VP. FTIR results showed that P4VP could penetrate up to 30 µm of Nafion 117 membrane. Proton conductivity and methanol permeability of modified membrane were lower than those of Nafion 117. Both decreased with increasing concentration of dipping solution and dipping time. Methanol permeability was observed to be more dependent on the penetration depth of P4VP. Water uptake of the modified membrane, the important factor in a fuel cell, was lower than that of Nafion 117. Water uptake also decreased with increasing of P4VP weight. On the basis of this study, the thinner the P4VP layer on the Nafion 117 membrane, the higher was the proton conductivity. Methanol permeability decreased exponentially as a function of P4VP weight percent. Copyright © 2006 Society of Chemical Industry     

Surface treatment of phosphate glass fibers using 2‐hydroxyethyl methacrylate: Fabrication of poly(caprolactone)‐based composites

2‐Hydroxyethyl methacrylate (HEMA) solution (1–10 wt %) was prepared in methanol and phosphate glass fibers were immersed in that solution for 5 min before being cured (irradiation time: 30 min) under UV radiation. Maximum polymer loading (HEMA content) was found for the 5 wt % HEMA solution. Degradation tests of the fibers in aqueous medium at 37°C suggested that the degradation of the HEMA‐treated fibers was lower than that of the untreated fibers. X‐ray photoelectron spectroscopy revealed that HEMA was present on the surface of the fibers. Using 5 wt % HEMA‐treated fibers, poly(caprolactone) matrix unidirectional composites were fabricated by in situ polymerization and compression molding. For in situ polymerization, it was found that 5 wt % HEMA‐treated fiber‐based composites had higher bending strength (13.8% greater) and modulus (14.0% greater) than those of the control composites. For compression molded composites, the bending strength and modulus values for the HEMA‐treated samples were found to be 27.0 and 31.5% higher, respectively, than the control samples. The tensile strength, tensile modulus, and impact strength of the HEMA composites found significant improvement than that of the untreated composites. The composites were investigated by scanning electron microscopy after 6 weeks of degradation in water at 37°C. It was found that HEMA‐treated fibers inside the composite retained much of their original integrity while the control samples degraded significantly. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

The effectiveness of magnesium carbonate‐based flame retardants for poly(ethylene‐co‐vinyl acetate) and poly(ethylene‐co‐ethyl acrylate)

In this report we outline recent work on the evaluation of magnesium carbonate‐based flame retardants for polymers commonly used in halogen‐free flame retardant wire and cable applications: poly(ethylene‐co‐vinyl acetate) (EVA) and poly(ethylene‐co‐ethyl acrylate) (EEA). Natural magnesium carbonate (magnesite), synthetic magnesium carbonate (hydromagnesite), and hydromagnesite/huntite blends were combined with EVA or EEA and tested for flame retardancy effectiveness with the cone calorimeter. The flammability results showed that the effectiveness of these carbonates was polymer dependent, suggesting that polymer degradation chemistry played a role in the flammability reduction mechanism. Hydromagnesites were, in general, more effective in reducing flammability, being comparable in performance to magnesium hydroxide. Finally, we report some polymer–clay (organically treated montmorillonite and magadiite) + magnesium carbonate flame retardant results which showed that the nanocomposite yielded mixed results. Specifically, the polymer–clay nanocomposite samples did not always yield the greatest reductions in peak heat release rate. Copyright © 2007 John Wiley & Sons, Ltd.     

Mechanical characteristics of poly(2‐hydroxyethyl methacrylate) hydrogels crosslinked with various difunctional compounds

Poly(2‐hydroxyethyl methacrylate) hydrogels were prepared in the presence of 30 wt% water using two series of crosslinking agents including divinylic (ethyleneglycol dimethacrylate, 1,4‐butanediol dimethacrylate, 2,3‐dihydroxybutanediol 1,4‐dimethacrylate) and diallylic (1,5‐hexadiene‐3,4‐diol and 1,5‐hexadiene) compounds, over a concentration range between 0.1 and 5 mol%. The resulting polymers were swollen in water to yield homogeneous transparent hydrogels. These hydrogels were characterised in terms of equilibrium swelling in water, tensile properties and compression stress–strain measurements. The influences of the nature and the concentration of crosslinking agent on the swelling behaviour and the mechanical properties of these hydrogels were investigated. The crosslinking efficiency of two representative agents (ethyleneglycol dimethacrylate and 1,5‐hexadiene‐3,4‐diol) was quantified by compression experiments. A much lower crosslinking efficiency (0.013) was observed for 1,5‐hexadiene‐3,4‐diol than for ethyleneglycol dimethacrylate (0.336). It is suggested that the low crosslinking efficiency of diallylic agents is responsible for a trend in properties different from that displayed by the gels crosslinked with dimethacrylates. A comparison was made to the similar effect observed previously in heterogeneous PHEMA hydrogels. © 2001 Society of Chemical Industry     

Comparison of viscoelastic properties of polydimethylsiloxane/poly(2‐hydroxyethyl methacrylate) IPNs with their physical blends

Interpenetrating polymer networks (IPNs) of polydimethylsiloxane (PDMS) and poly(2‐hydroxyethyl methacrylate) (PHEMA) were prepared by sequential method. The dynamic mechanical parameters of obtained IPNs and their variations with the structural composition were evaluated. The results for the IPNs were compared with corresponding physically blended systems. The tensile properties and damping factor (tan δ) were assessed by stress–strain measurement and dynamic mechanical thermal analysis (DMTA), respectively. The glass–rubber transition temperature (T_g) was assessed by DMTA and differential scanning calorimetry (DSC). The results showed higher tensile strength and elongation at break for IPNs than those for physical blends. The shifts of T_g for that two components that make up the IPNs were greater than those for corresponding blends. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3480–3485, 2002     

Miscibility and crystallization behavior of the solution‐blended sulfonated poly(phenylene oxide)/ poly(styrene‐co‐4‐vinyl pyridine) blend

The miscibility and crystallization behavior of the solution‐blended lightly sulfonated poly(phenylene oxide) (SPPO)/poly(styrene‐co‐4‐vinylpyridine) (PSVP) blend were investigated by conventional and modulated differential scanning calorimetry (MDSC). It was found that the original blend film is actually composed of a crystalline SPPO phase and a noncrystalline compatible SPPO–PSVP phase. The original phase‐segregated structure will evolve to a noncrystalline homogenous structure by subsequent high temperature annealing. The resulting good miscibility was attributed to two aspects: one is that the SPPO crystalline structure could be destroyed as annealing temperature is high enough; the other is that the acid–base interaction between the sulfonic group of SPPO and the pyridine ring of PSVP could promote mixing of different components effectively. And such acid–base interaction was demonstrated by ¹C NMR spectra. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2843–2848, 2001