Study of hydrogen‐bonding strength in poly(ϵ‐caprolactone) blends by DSC and FTIR

The hydrogen‐bonding strength of poly(?‐caprolactone) (PCL) blends with three different well‐known hydrogen‐bonding donor polymers [i.e., phenolic, poly(vinyl‐phenol) (PVPh), and phenoxy] was investigated with differential scanning calorimetry and Fourier transform infrared spectroscopy. All blends exhibited a single glass‐transition temperature with differential scanning calorimetry, which is characteristic of a miscible system. The strength of interassociation depended on the hydrogen‐bonding donor group in the order phenolic/PCL > PVPh/PCL > phenoxy/PCL, which corresponds to the q value of the Kwei equation. In addition, the interaction energy density parameter calculated from the melting depression of PCL with the Nishi–Wang equation resulted in a similar trend in terms of the hydrogen‐bonding strength. Quantitative analyses on the fraction of hydrogen‐bonded carbonyl groups in the molten state were made with Fourier transform infrared spectroscopy for all systems, and good correlations between thermal behaviors and infrared results were observed. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1348–1359, 2001     

Miscibility,specific interactions,and self‐assembly behavior of phenolic/polyhedral oligomeric silsesquioxane hybrids

The miscibility of a phenolic resin with polyhedral oligomeric silsesquioxane (POSS) hybrids and the specific interactions between them were investigated with Fourier transform infrared (FTIR) spectroscopy and wide‐angle X‐ray diffraction (WAXD). An analysis of the morphology and microstructure was performed with polarized optical microscopy and atomic force microscopy (AFM). The interassociation equilibrium constant between the phenolic resin and POSS (38.7) was lower than the self‐association equilibrium constant of pure phenolic (52.3) according to the Painter–Coleman association model. This result indicated that POSS was partially miscible with the phenolic resin. A polarized optical microscopy image of a phenolic/POSS hybrid material (20 wt % POSS) indicated that the crystals of POSS were arranged evenly in the phenolic matrix; the self‐assembled array of POSS crystals was also confirmed by AFM. This phenomenon was consistent with the FTIR spectroscopy and WAXD analyses. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1127–1136, 2004     

Miscibility and hydrogen‐bonding interactions in blends of carbon dioxide/epoxy propane copolymer with poly(p‐vinylphenol)

The miscibility and hydrogen‐bonding interactions of carbon dioxide and epoxy propane copolymer to poly(propylene carbonate) (PPC)/poly(p‐vinylphenol) (PVPh) blends were investigated with differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy and X‐ray photoelectron spectroscopy (XPS). The single glass‐transition temperature for each composition showed miscibility over the entire composition range. FTIR indicates the presence of strong hydrogen‐bonding interassociation between the hydroxyl groups of PVPh and the oxygen functional groups of PPC as a function of composition and temperature. XPS results testify to intermolecular hydrogen‐bonding interactions between the oxygen atoms of carbon–oxygen single bonds and carbon–oxygen double bonds in carbonate groups of PPC and the hydroxyl groups of PVPh by the shift of C_1s peaks and the evolution of three novel O_1s peaks in the blends, which supports the suggestion from FTIR analyses. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1957–1964, 2002     

Strength of hydrogen bonding in the novolak-type phenolic resin blends

The specific interaction strength of novolak-type phenolic resin blended with three similar polymers [i.e., poly(ethylene oxide) (PEO), poly(ethylene glycol) (PEG), and poly(vinyl alcohol) (PVA)] were characterized by means of glass transition temperature behavior and Fourier transform infrared (FTIR) spectroscopy. The interassociation formed within phenolic blends with the addition of a modifier not only overcomes the effect of self-association of the phenolic upon blending, but also increases the strength of phenolic blend. The strength of interassociation within the phenolic blend is the function of the hydrogen bonding group of a modifier, in increasing order, is phenolic/PVA, phenolic/PEG, and phenolic/PEO blend, corresponding to the result of “q” value in the Kwei equation. The FTIR result is in agreement with the inference of T_g behavior. In addition, the fact that the specific strength of hydrogen bonding of hydroxyl–hydroxyl is stronger than that of hydroxyl–ether can also be concluded. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 1721–1729, 1998     

Poly(hydroxyether of phenolphthalein) and its blends with poly(ethylene oxide)

Poly(hydroxyether of phenolphthalein) (PPH) was synthesized through the polycondensation of phenolphthalein with epichlorohydrin. It was characterized by Fourier transform infrared (FTIR) spectroscopy, NMR spectroscopy, and differential scanning calorimetry (DSC). The miscibility of the blends of PPH with poly(ethylene oxide) (PEO) was established on the basis of the thermal analysis results. DSC showed that the PPH/PEO blends prepared via casting from N,N‐dimethylformamide possessed single, composition‐dependent glass‐transition temperatures. Therefore, the blends were miscible in the amorphous state for all compositions. FTIR studies indicated that there were competitive hydrogen‐bonding interactions with the addition of PEO to the system, which were involved with OH…O?C〈, ? OH…? OH, and ? OH vs ether oxygen atoms of PEO hydrogen bonding, that is both intramolecular and intermolecular, between PPH and PEO). Some of the hydroxyl stretching vibration bands significantly shifted to higher frequencies, whereas others shifted to lower frequencies, and this suggested the formation of hydrogen bonds between the pendant hydroxyls of PPH and ether oxygen atoms of PEO, which were stronger than the intramolecular hydrogen bonding between hydroxyls and carbonyls of PPH. The FTIR spectra in the range of carbonyl stretching vibrations showed that the hydroxyl‐associated carbonyl groups were partially set free because of the presence of the competitive hydrogen‐bonding interactions. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 466–475, 2003     

Thermodynamic properties of novolac-type phenolic resin blended with poly(ethylene oxide)

The thermodynamic properties of novolac type phenolic resin blended with poly(ethylene oxide) (PEO) were investigated by the Painter–Coleman association model (PCAM). Equilibrium constants and enthalpy corresponding to the interaction between phenolic and poly(ethylene oxide) were calculated from the Fourier transform infrared spectroscopy of low molecular weight analogues in dilute solutions. The association parameters of the model compounds are transferred to the corresponding polymers, to predict the Gibbs free energy, phase behavior, and the degree of hydrogen bonding in the polymer blend. The heat capacity (C_P) and the excess heat capacity (ΔC_P) are used to verify the validity of PCAM model on predicting the thermodynamics properties of phenolic/PEO blend. It is found that the hydrogen bonding interaction dominates at moderate temperatures, which is outweighed by the dispersion force at higher temperature or high PEO compositions. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 1647–1655, 1998     

Inorganic–organic hybrids involving poly(ε‐caprolactone) and silica network: Hydrogen‐bonding interactions and isothermal crystallization kinetics

Inorganic–organic hybrids mediated by hydrogen‐bonding interactions involving silicon oxide network and poly(ε‐caprolactone) (PCL) were prepared via an in situ sol–gel process of tetraethoxysilane in the presence of PCL. Fourier transform infrared spectroscopy indicated that there were hydrogen‐bonding interactions between carbonyls of PCL and silanol hydroxyls that were formed by incomplete polycondensation in the sol–gel process. In terms of the frequency shift of the hydroxyl stretching vibration bands, it is concluded that the strength of the interassociation between PCL and silicon oxide networks is weaker than that of the self‐association in the control silica network. The phenomenon of equilibrium melting point depression was observed for the PCL/silica system. The hybridization of PCL with silica network causes a considerable increase in the overall crystallization rate and dramatically influences the mechanism of nucleation and growth of the PCL crystallization. The analysis of isothermal crystallization kinetic data according to the Hoffman‐Lauritzen theory shows that with increasing silica content in the hybrids, the surface energy of extremity surfaces increases dramatically for the hybrids. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2594–2603, 2005     

Physically cross‐linked networks of POSS‐capped poly(acrylate amide)s: Synthesis,morphologies, and shape memory behavior

In this work, we synthesized a novel organic–inorganic semitelechelic polymer from polyhedral oligomeric silsesquioxane (POSS) and poly(acrylate amide) (PAA) via reversible addition‐fragmentation chain transfer (RAFT) polymerization. The organic–inorganic semitelechelic polymers have been characterized by means of nuclear magnetic resonance spectroscopy, thermal gravimetric analysis, and dynamic mechanical thermal analysis. It was found that capping POSS groups to the single ends of PAA chains caused a series of significant changes in the morphologies and thermomechanical properties of the polymer. The organic–inorganic semitelechelics were microphase‐separated; the POSS microdomains were formed via the POSS–POSS interactions. In a selective solvent (e.g., methanol), the organic–inorganic semitelechelics can be self‐assembled into the micelle‐like nanoobjects. Compared to plain PAA, the POSS‐capped PAAs significantly displayed improved surface hydrophobicity as evidenced by the measurements of static contact angles and surface atomic force microscopy. More importantly, the organic–inorganic semitelechelics displayed typical shape memory properties, which was in marked contrast to plain PAA. The shape memory behavior is attributable to the formation of the physically cross‐linked networks from the combination of the POSS–POSS interactions with the intermolecular hydrogen‐bonding interactions in the organic–inorganic semitelechelics. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 587–600     

Thermal,mechanical, and morphological properties of phenolic resin/silica hybrid ceramers

Phenolic resin/silica hybrid ceramers were prepared through sol–gel technology. Differential scanning calorimetry and thermogravimetric analysis methods were utilized to study the thermal properties of the fabricated hybrid ceramers. The results showed that the heat resistance of the ceramers was slightly higher than that of the phenolic resin. The hydrogen bonding occurring inside the hybrid ceramers was investigated by Fourier transform infrared. The results showed that the intermolecular hydrogen bonding between the phenolic resin and the silica was stronger than the intramolecular hydrogen bonding between the phenolic resin molecules themselves. Furthermore, the hybrid ceramers were utilized to fabricate carbon‐fiber‐reinforced composites. The fabricated ceramer composites possessed better flexural strength and flexural modulus than that fabricated from neat phenolic resin. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1699–1706, 2000     

Thermal,mechanical, and morphological properties of novolac‐type phenolic resin blended with fullerenol polyurethane and linear polyurethane

Fullerenol polyurethane (C₆₀‐PU) and linear polyurethane (linear‐PU) modified phenolic resins were prepared in this study. Phenolic resin/C₆₀‐PU and phenolic resin/linear‐PU blends show good miscibility as a result of the intermolecular hydrogen bonding existing between phenolic resin and PU modifiers. DSC and thermogravimetric analysis methods were used to study the thermal properties of phenolic resin blended with different types of PUs. The intermolecular hydrogen bonding that existed between phenolic resin and C₆₀‐PU was investigated by Fourier transform infrared spectroscopy. The morphology and mechanical properties of phenolic resin/C₆₀‐PU and phenolic resin/linear‐PU blends were also investigated. The char yield of the modified phenolic resins decreased with increasing PU modifier content. Significant improvement in the toughness of the modified phenolic resins was observed. The improvements of impact strength were 27.4% for the phenolic resin/linear‐PU system and 54.3% for the phenolic resin/C₆₀‐PU system, respectively, both with 3 phr linear‐PU and C₆₀‐PU content. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2436–2443, 2001     

Screening effects in blends of a hyperbranched,dendrimer‐like polyester with poly(4‐vinyl phenol)

We previously reported self‐association and interassociation equilibrium constant values describing hydrogen bonding in solutions of a hyperbranched polyester. These allow us to estimate the extent of intramolecular screening and the fraction of same‐chain contacts in this system as a function of generation number. In this article, we use a similar method to evaluate the degree of intramolecular screening in polymer blends. The calculated values reported here are consistent with those previously reported in our solution study, confirming the validity of the calculation procedures we used to evaluate the accessibility of functional groups in these highly branched systems. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1651–1658, 2001     

Phosphonyl/hydroxyl hydrogen bonding–induced miscibility of poly(arylene ether phosphine oxide/sulfone) statistical copolymers with poly(hydroxy ether) (phenoxy resin): Synthesis and characterization

High molecular weight bisphenol A or hydroquinone‐based poly(arylene ether phosphine oxide/sulfone) homopolymer or statistical copolymers were synthesized and characterized by thermal analysis, gel permeation chromatography, and intrinsic viscosity. Miscibility studies of blends of these copolymers with a (bisphenol A)‐epichlorohydrin based poly(hydroxy ether), termed phenoxy resin, were conducted by infrared spectroscopy, dynamic mechanical analysis, and differential scanning calorimetry. All of the data are consistent with strong hydrogen bonding between the phosphonyl groups of the copolymers and the pendent hydroxyl groups of the phenoxy resin as the miscibility‐inducing mechanism. Complete miscibility at all blend compositions was achieved with as little as 20 mol % of phosphine oxide units in the bisphenol A poly(arylene ether phosphine oxide/sulfone) copolymer. Single glass transition temperatures (T_g) from about 100 to 200°C were achieved. Replacement of bisphenol A by hydroquinone in the copolymer synthesis did not significantly affect blend miscibilities. Examination of the data within the framework of four existing blend T_g composition equations revealed T_g elevation attributable to phosphonyl/hydroxyl hydrogen bonding interactions. Because of the structural similarities of phenoxy, epoxy, and vinylester resins, the new poly(arylene ether phosphine oxide/sulfone) copolymers should find many applications as impact‐improving and interphase materials in thermoplastics and thermoset composite blend compositions. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 1849–1862, 1999     

Nanostructured thermoset epoxy resin templated by an amphiphilic poly(ethylene oxide)‐block‐poly(dimethylsiloxane) diblock copolymer

An amphiphilic poly(ethylene oxide)‐block‐poly(dimethylsiloxane) (PEO–PDMS) diblock copolymer was used to template a bisphenol A type epoxy resin (ER); nanostructured thermoset blends of ER and PEO–PDMS were prepared with 4,4′‐methylenedianiline (MDA) as the curing agent. The phase behavior, crystallization, hydrogen‐bonding interactions, and nanoscale structures were investigated with differential scanning calorimetry, Fourier transform infrared spectroscopy, transmission electron microscopy, and small‐angle X‐ray scattering. The uncured ER was miscible with the poly(ethylene oxide) block of PEO–PDMS, and the uncured blends were not macroscopically phase‐separated. Macroscopic phase separation took place in the MDA‐cured ER/PEO–PDMS blends containing 60–80 wt % PEO–PDMS diblock copolymer. However, the composition‐dependent nanostructures were formed in the cured blends with 10–50 wt % PEO–PDMS, which did not show macroscopic phase separation. The poly(dimethylsiloxane) microdomains with sizes of 10–20 nm were dispersed in a continuous ER‐rich phase; the average distance between the neighboring microdomains was in the range of 20–50 nm. The miscibility between the cured ER and the poly(ethylene oxide) block of PEO–PDMS was ascribed to the favorable hydrogen‐bonding interaction. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3042–3052, 2006     

Self‐assembly and secondary structures of linear polypeptides tethered to polyhedral oligomeric silsesquioxane nanoparticles through click chemistry

In this study, we used click chemistry to synthesize a new macromolecular self‐assembling building blocks, linear polypeptide‐b‐polyhedral oligomeric silsesquioxane (POSS) copolymers, from a mono‐azido–functionalized POSS (N₃‐POSS) and several alkyne‐poly(γ‐benzyl‐L ‐glutamate) (alkyne‐PBLG) systems. The incorporation of the POSS unit at the chain end of the PBLG moiety allowed intramolecular hydrogen bonding to occur between the POSS and PBLG units, thereby enhancing the α‐helical conformation in the solid state, as determined through Fourier transform infrared spectroscopy and wide‐angle X‐ray diffraction analyses. POSS‐b‐PBLG underwent hierarchical self‐assembly, characterized using small‐angle X‐ray scattering, to form a bilayer‐like nanostructure featuring α‐helical or β‐sheet conformations and POSS aggregates. Thermogravimetric analysis indicated that the thermal degradation temperature increased significantly after incorporation of the POSS moiety, which presumably formed an inorganic protection layer on the nanocomposite's surface. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Miscible blends of poly(vinyl phenyl ketone) and poly(4‐vinyl phenol)

An analysis by differential scanning calorimetry, modulated differential scanning calorimetry, and Fourier transform infrared spectroscopy (FTIR) indicates that blends of poly(vinyl phenyl ketone) (PVPhK) and poly(4‐vinyl phenol) (P4VPh) are miscible at ambient temperature. Miscibility, ascertained, is supported by the existence of a single glass transition for each composition of the PVPhK/P4VPh blends. The FTIR spectroscopy analysis demonstrates the formation of hydrogen bonds between carbonyl groups of PVPhK and hydroxyl groups of P4VPh. This specific interaction has a crucial role on the miscibility behavior of PVPhK/P4VPh blends. The evolution of the glass transition of the PVPhK, P4VPh, and its blends as a function of mixture composition shows negative deviations with to respect to the ideal mixing rule, and both Fox and Gordon–Taylor equations predict this behavior successfully. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2404–2411, 2006     

Diphenol miscibility effect on the immiscible polyester/polyether binary blends through intermolecular hydrogen‐bonding interaction

Miscibility and hydrogen bonding interaction have been investigated for the binary blends of poly(butylene adipate‐co‐44 mol % butylene terephthalate)[P(BA‐co‐BT)] with 4,4'‐thiodiphenol (TDP) and poly(ethylene‐ oxide)(PEO) with TDP; and the ternary blends of P(BA‐co‐BT)/PEO/TDP by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The DSC results indicated that the binary blends of P(BA‐co‐BT)/TDP and PEO/TDP were miscible because each blend showed only one composition‐dependent glass‐transition over the entire range of the blend composition. The formation of intermolecular hydrogen bonds between the hydroxyl groups of TDP and the carbonyl groups of P(BA‐co‐BT), and between the hydroxyl groups of TDP and the ether groups of PEO was confirmed by the FTIR spectra. According to the glass‐transition temperature measured by DSC, P(BA‐co‐BT) and PEO, their binary blends were immiscible over the entire range of blend composition, however, the miscibility between P(BA‐co‐BT) and PEO was enhanced through the TDP‐mediated intermolecular hydrogen bonding interaction. It was concluded that TDP content of about 5–10% may possibily enhance miscibility between P(BA‐co‐BT) and PEO via a hydrogen bonding interaction. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2971–2982, 2004     

Structural characteristics of phenol formaldehyde novolak resin depending on polycondensation type using molecular simulation

Phenol formaldehyde novolak resins have various structures depending on the polycondensation types. Their structures were characterized using molecular mechanics and molecular dynamics. Dimer, tetramer, hexamer, octamer, and decamer of the resins with the ortho–ortho, ortho–para, and para–para sequences were calculated. The ortho–ortho resins have the structural characteristics of intramolecular hydrogen bonds between hydroxyl groups of the adjacent phenolic units. For the ortho–para and para–para resins, the intramolecular hydrogen bonds are formed mainly between hydroxyl groups of the backbone phenolic units. The para–para resins also have intramolecular hydrogen bonds between hydroxyl groups of the branched phenolic units. A factor determining the structural characteristics of the resins was found to be the geometry of the basic unit (dimer). The order of the end‐to‐end distances between hydrogen atoms on the para‐position of the basic units of the resins is ortho–ortho resin < ortho–para resin < para–para resin. The calculational results were found to be consistent with the gel permeation chromatography (GPC) analysis. Copyright © 2001 John Wiley & Sons, Ltd.     

Preparation and properties of polyhedral oligosilsequioxane tethered aromatic polyamide nanocomposites through Michael addition between maleimide‐containing polyamides and an amino‐functionalized polyhedral oligosilsequioxane

Polyhedral oligosilsequioxane (POSS) tethered aromatic polyamide nanocomposites with various POSS fractions were prepared through Michael addition between maleimide‐containing polyamides and amino‐functionalized POSS. The chemical structures of the polyamide–POSS nanocomposites were characterized with Fourier transform infrared and ¹H NMR. The polyamide–POSS nanocomposites exhibited good homogeneity in scanning electron microscopy and transmission electron microscopy observations. POSS modification increased the storage modulus and Young's modulus of the polyamides, slightly decreased their glass‐transition temperatures from 312 to 305 °C, and significantly lowered their dielectric constants from 4.45 to 3.35. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4632–4643, 2006     

Miscibility and intermolecular specific interactions in thermosetting blends of bisphenol S epoxy resin with poly(ethylene oxide)

Thermosetting blends composed of phloroglucinol‐cured bisphenol S epoxy resin and poly(ethylene oxide) (PEO) were prepared via the in situ curing reaction of epoxy in the presence of PEO, which started from initially homogeneous mixtures of diglycidyl ether of bisphenol S, phloroglucinol, and PEO. The miscibility of the blends after and before the curing reaction was established on the basis of thermal analysis (differential scanning calorimetry). Single and composition‐dependent glass‐transition temperatures (T_g's) were observed for all the blend compositions after and before curing. The experimental T_g's could be explained well by the Gordon–Taylor equation. Fourier transform infrared spectroscopy indicated that there were competitive hydrogen‐bonding interactions in the binary thermosetting blends upon the addition of PEO to the system, which was involved with the intramolecular and intermolecular hydrogen‐bonding interactions, that is, OH···O?S, OH···OH, and OH, versus ether oxygen atoms of PEO between crosslinked epoxy and PEO. On the basis of infrared spectroscopy results, it was judged that from weak to strong the strength of the hydrogen‐bonding interactions was in the following order: OH···O?S, OH···OH, and OH versus ether oxygen atoms of PEO. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 359–367, 2005     

Effect of inert diluent segment on the miscibility behavior of poly(vinylphenol) with poly(acetoxystyrene) blends

Polymer blends of poly(vinylphenol) (PVPh) and poly(styrene‐co‐vinylphenol) with poly(p‐acetoxystyrene) (PAS) were prepared by solution casting from tetrahydrofuran solution. The thermal properties and hydrogen bonding of the blends were investigated by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy. Although hydrogen bonding existed between the PVPh and PAS segments, the experimental results indicated that PVPh is immiscible with PAS as shown by the existence of two glass‐transition temperatures over the entire composition range by DSC. This phenomenon is attributed to the strong self‐association of PVPh, intramolecular screening, and functional group accessibility effects of the PVPh/PAS blend system. However, the incorporation of an inert diluent moiety such as styrene into the PVPh chain renders the modified polymer to be miscible with PAS. Copolymers containing between 16 and 51 mol % vinylphenol were fully miscible with PAS according to DSC studies. These observed results were caused by the reduction of the strong self‐association of PVPh and the increase of the interassociation between PVPh and PAS segments with the incorporation of styrene on the PVPh chain. According to the Painter‐Coleman association model, the interassociation equilibrium constant of PVPh/PAS blends was determined by a model compound and polymer blend. Good correlation between these two methods was obtained after considering the intramolecular screening and functional group accessibility effect in the polymer blend. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1661–1672, 2002