Synthesis,characterization of novel interacting blends of acrylated poly(ester-amide)s containing epoxy residues with vinyl ester resin

Unsaturated bisamic acids were prepared by reaction between maleic anhydride and different aromatic diamines. Unsaturated poly(ester-amide) resin (UPEAs) was prepared by reaction of diglycidylether of bisphenol-A (DGEBA) with unsaturated bisamic acids. Acrylation of Unsaturated poly(ester-amide)s (UPEAs) was carried out to afford acrylated UPEAs resin (i.e., AUPEAs). Interacting blends of Acrylated unsaturated poly(ester-amide)s (AUPEAs) with vinyl ester epoxy (VE) resin were prepared. APEAs and AUPEAs were characterized by elemental analysis, molecular weight determined by vapor pressure osmometer and by IR spectral study and by thermogravimetry. The curing of interacting blends was monitored on differential scanning calorimeter (DSC). Based on DSC data in situ glass reinforced composites of the resultant blends have been prepared and characterized for mechanical, electrical and chemical properties. Unreinforced blends were characterized thermo-gravimetrically (TGA).     

Miscibility and crystallization behavior of PBT/epoxy blends

The miscibility and the isothermal crystallization kinetics for PBT/Epoxy blends have been studied by using differential scanning calorimetry, and several kinetic analyses have been used to describe the crystallization process. The Avrami exponents n were obtained for PBT/Epoxy blends. An addition of small amount of epoxy resin (3%) leads to an increase in the number of effective nuclei, thus resulting in an increase in crystallization rate and a stronger trend of instantaneous three‐dimensional growth. For isothermal crystallization, crystallization parameter analysis showed that epoxy particles could act as effective nucleating agents, accelerating the crystallization of PBT component in the PBT/Epoxy blends. The Lauritzen–Hoffman equation for DSC isothermal crystallization data revealed that PBT/Epoxy 97/3 had lower nucleation constant K_g than 100/0, 93/7, and 90/10 PBT/Epoxy blends. Analysis of the crystallization data of PBT/Epoxy blends showed that crystallization occurs in regime II. The fold surface free energy, σ_e = 101.7–58.0 × 10^?3 J/m², and work of chain folding, q = 5.79–3.30 kcal/mol, were determined. The equilibrium melting point depressions of PBT/Epoxy blends were observed and the Flory–Huggins interaction parameters were obtained. It indicated that these blends were thermodynamically miscible in the melt. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1320–1330, 2006     

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     

Miscibility,morphology and fracture toughness of epoxy resin/poly(vinyl acetate) blends

Diglycidylether of bisphenol A (DGEBA)/poly(vinyl acetate) (PVAc) blends cured with 4,4-diaminodiphenylmethane (DDM) were prepared. The miscibility and phase behavior were investigated by means of differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM). The study results indicate that the epoxy precursor (DGEBA)/PVAc blends are clearly miscible at the entire composition and theTg values experimentally obtained are in a good agreement with those predicted by Fox equation. Cured at elevated temperature, all the DDM-cured blends underwent phase separation and display two-phase morphology. When PVAc content is more than 10 wt%, the thermoplastics-modified resins began to show a co-continuous phase structure. It is the cocontinuous structure that leads to a significantly-improved toughness inK _ic. Morphologic investigation of the surfaces of fracture mechanic measurement specimens indicates that the toughening effect of the thermoplastics-modified epoxy resins may arise mainly from the ductile yielding of PVAc.     

A novel comparative study of different layered silicate clay types on exfoliation process and final nanostructure of trifunctional epoxy nanocomposites

The effect of three different organically modified layered silicate clays (Nanomer I.30E, Cloisite 30B and Nanofil SE 3000) on the exfoliation process and on the thermal properties and nanostructure of cured trifunctional epoxy resin based nanocomposites was studied. Optical microscopy showed that the best and poorest qualities of clay distribution in the epoxy matrix were obtained with Nanofil SE 3000 and Nanomer I.30E, respectively. However, the isothermal differential scanning calorimetry scans show that, of the three systems, it is only the Nanomer clay that promotes intra-gallery reaction due to homopolymerisation, appearing as an initial rapid peak prior to the cross-linking reaction. This rapid intra-gallery reaction is not present in the curing curve for the Cloisite and Nanofil systems. This fact implies that the fully cured nanostructure of the Cloisite and Nanofil system is poorly exfoliated, which is confirmed by small angle X-ray scattering which shows a scattering peak for these systems at around 2.53°, corresponding to about 3.5 nm d-spacing.     

Synthesis of poly(vinyl laurate)‐b‐poly(vinyl stearate) diblock copolymers by cobalt‐mediated radical polymerization in solution

Poly(vinyl laurate) (PVL) and poly(vinyl stearate) (PVS) were synthesized by means of cobalt‐mediated radical polymerization (CMRP). Cobalt(II) diacetylacetonate (Co(acac)₂) was demonstrated to control the radical polymerization of these monomers in solution. Molecular weights up to 15,000 g·mol^?1 were obtained with reasonably low polydispersity indices (PDI < 1.3). The efficiency of the redox initiator [lauroyle peroxide (LPO)/citric acid (CA)] was found to be low (around 10%) as already reported for vinyl acetate. The solvent and temperature were found to have a very weak influence on the initiator efficiency. It appeared that CA played no role in the initiation process that only involved a redox reaction between LPO and Co(acac)₂. PVL‐b‐PVS diblock copolymers could be synthesized using two strategies: (1) Sequential addition, that is, addition of the second monomer (VS) at high conversion of the first one (VL). (2) Macroinitiator technique, that is, isolation of a PVL macroinitiator then polymerization of VS from this cobalt functionalized macroinitiator. Both techniques allowed the synthesis of diblock copolymers with molar masses around 25,000 g·mol^?1 and PDI lower than 1.4. The resulting materials were characterized by DSC, revealing that both blocks exhibit side‐chain crystallinity and phase segregate in the bulk. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Competitive specific interactions in miscible blends of poly(hydroxyether terephthalate ester) and poly(4‐vinyl pyridine)

The miscibility of poly(hydroxyether terephthalate ester) (PHETE) with poly(4‐vinyl pyridine) (P4VP) was established on the basis of thermal analysis. Differential scanning calorimetry showed that each blend displayed a single glass‐transition temperature (T_g), which is intermediate between those of the pure polymers and varies with the composition of blend. The T_g‐composition relationship can be well described with Kwei equation with k = 1 and q = ?30.8 (K), suggesting the presence of the intermolecular specific interactions in the blend system. To investigate the intermolecular specific interactions in the blends, the model compounds such as 1,3‐diphenoxy‐2‐propanol, 4‐methyl pyridine, and ethyl benzoate were used to determine the equilibrium constants, according to Coleman and Painter model, to account for the association equilibriums of several structural moieties, using liquid Fourier transform infrared difference spectroscopy. In terms of the difference in the association equilibrium constant, it is proposed that there are the competitive specific interactions in the blends, which were confirmed by means of Fourier transform infrared spectroscopy of the blends. It is observed that upon adding P4VP to the system, the ester carbonyls of PHETE that were H‐bonded with the hydroxyl groups were released because of the formation of the stronger interchain association via the hydrogen bonding between the hydroxyls of PHETE and tertiary nitrogen atoms of P4VP. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1618–1626, 2006     

Polycondensations of hydroxycarboxylic acids derived from optically active aminoalcohols and acid anhydrides—syntheses of functional poly(ester-amide)s

Syntheses and polycondensations of optically active hydroxycarboxylic acids prepared from acid anhydrides and aminoalcohols were carried out. Novel polymers with M̄_n 9900–27,200 were obtained by the polycondensations of hydroxycaboxylic acids derived from maleic or succinic acid using 1.2 eq. of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC · HCl) in DMF (2M) at room temperature for 8 h in satisfactory yields. Meanwhile, a hydroxycarboxylic acid obtained from phthalic acid afforded no polymer but a phthalimide derivative. The radical additions of ethanethiol or mercaptoethanol with the polymers derived from maleic anhydride proceeded smoothly in satisfactory incorporation ratios (65–98%), respectively. The polymer obtained from succinic anhydride and 2-aminoethanol showed hydrolytic degradability. © 1997 John Wiley & Sons, Inc.     

Dynamic mechanical behavior of acrylonitrile butadiene rubber/poly(ethylene‐co‐vinyl acetate) blends

The dynamic mechanical behavior of uncrosslinked (thermoplastic) and crosslinked (thermosetting) acrylonitrile butadiene rubber/poly(ethylene‐co‐vinyl acetate) (NBR/EVA) blends was studied with reference to the effect of blend ratio, crosslinking systems, frequency, and temperature. Different crosslinked systems were prepared using peroxide (DCP), sulfur, and mixed crosslink systems. The glass‐transition behavior of the blends was affected by the blend ratio, the nature of crosslinking, and frequency. sThe damping properties of the blends increased with NBR content. The variations in tan δ_max were in accordance with morphology changes in the blends. From tan δ values of peroxide‐cured NBR, EVA, and blends the crosslinking effect of DCP was more predominant in NBR. The morphology of the uncrosslinked blends was examined using scanning electron and optical microscopes. Cocontinuous morphology was observed between 40 and 60 wt % of NBR. The particle size distribution curve of the blends was also drawn. The Arrhenius relationship was used to calculate the activation energy for the glass transition of the blends, and it decreased with an increase in the NBR content. Various theoretical models were used to predict the modulus of the blends. From wide‐angle X‐ray scattering studies, the degree of crystallinity of the blends decreased with an increasing NBR content. The thermal behavior of the uncrosslinked and crosslinked systems of NBR/EVA blends was analyzed using a differential scanning calorimeter. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1556–1570, 2002     

Segmented block copolymers of poly(ethylene glycol) and poly(ethylene terephthalate)

A new series of segmented copolymers were synthesized from poly(ethylene terephthalate) (PET) oligomers and poly(ethylene glycol) (PEG) by a two‐step solution polymerization reaction. PET oligomers were obtained by glycolysis depolymerization. Structural features were defined by infrared and nuclear magnetic resonance (NMR) spectroscopy. The copolymer composition was calculated via ¹H NMR spectroscopy. The content of soft PEG segments was higher than that of hard PET segments. A single glass‐transition temperature was detected for all the synthesized segmented copolymers. This observation was found to be independent of the initial PET‐to‐PEG molar ratio. The molar masses of the copolymers were determined by gel permeation chromatography (GPC). © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4448–4457, 2004     

Liquid-state transitions (T>T g) of poly(vinyl alcohol)

The two liquid state transitions,T _ll andT _ll, of non-crystalline, uncrosslinked poly(vinyl alcohol) were determined by differential scanning calorimetry.T _ll increased as the molecular weightM _n increased, whileT _ll remained almost constant. Crosslinking and crystallinity lead to disappearance of the transitionT _ll. The transitionT _ll was linked to mobility of whole chains, whereasT _ll was characteristic of segmental mobility.     

Study on miscibility of poly(vinyl chloride) and polyepichlorohydrin by viscometric and thermal analysis

Viscometric analysis was carried out to study the miscibility of poly(vinyl chloride) (PVC) and polyepichlorohydrin (PECH) in various solvents, tetrahydrofuran (THF), methyl ethyl ketone (MEK) and dimethylformamide (DMF). The Krigbaum–Wall criterion is used here to evaluate the miscibility of the two components, and Δb is introduced which can be calculated from the viscosity curves. The results show that their attractive forces are predominant when dissolved in THF, while in MEK and DMF repulsive forces play a leading role. This is attributed to different solubilities of the two polymers in the three solvents and to different influences of the solvents on the conformation of the polymers. Thermal measurement was performed by differential scanning calorimetry to investigate the glass transition temperature (T_g) of the blends prepared from the three solvents. Phase separation is observed for the samples made from MEK and DMF, while for THF the sample exhibits a single phase.     

Miscible blends of poly(ethylene oxide) with brush copolymers of poly(vinyl alcohol)‐graft‐poly(l‐lactide)

Even though poly(ethylene oxide) (PEO) is immiscible with both poly(l ‐lactide) (PLLA) and poly(vinyl alcohol) (PVA), this article shows a working route to obtain miscible blends based on these polymers. The miscibility of these polymers has been analyzed using the solubility parameter approach to choose the proper ratios of the constituents of the blend. Then, PVA has been grafted with l ‐lactide (LLA) through ring‐opening polymerization to obtain a poly(vinyl alcohol)‐graft‐poly(l ‐lactide) (PVA‐g‐PLLA) brush copolymer with 82 mol % LLA according to ¹H and ¹³C NMR spectroscopies. PEO has been blended with the PVA‐g‐PLLA brush copolymer and the miscibility of the system has been analyzed by DSC, FTIR, OM, and SEM. The particular architecture of the blends results in DSC traces lacking clearly distinguishable glass transitions that have been explained considering self‐concentration effects (Lodge and McLeish) and the associated concentration fluctuations. Fortunately, the FTIR analysis is conclusive regarding the miscibility and the specific interactions in these systems. Melting point depression analysis suggests that interactions of intermediate strength and PLOM and SEM reveal homogeneous morphologies for the PEO/PVA‐g‐PLLA blends. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1217–1226     

Positron annihilation and differential scanning calorimetry studies of polyacrylamide and poly(dimethylacrylamide)/poly(ethylene glycol) blends

Positron annihilation lifetime spectroscopy and differential scanning calorimetry (DSC) measurements were performed for blends of polyacrylamide (PAM) and poly(ethylene glycol) (PEG) and blends of poly(dimethylacrylamide) (PDMAM) and PEG. The samples were prepared by codissolution in a concentration range of 0–100 wt % PEG. The thermal behavior, characterized by DSC measurements, showed similar variations of the glass‐transition temperatures (T_g's) with the PEG concentration for the two systems. Pure PAM and PDMAM presented T_g's of 188 and 111 °C, respectively. A relatively small and nearly linearly decreasing T_g was observed for the two systems in the range of 20–80 wt % PEG. PEG crystals were present in all blend compositions, and no melting point depression was observed. The thermal results pointed to the partial miscibility of the blends. The degree of crystallinity of PEG increased with increasing PEG concentration for the PDMAM/PEG systems. The ortho‐positronium lifetime (τ₃) increased with increasing PEG concentration for both blends. However, the parameter of the ortho‐positronium formation probability (I₃) decreased with the PEG concentration. The product τI₃, which was proportional to the total free volume fraction, was approximately constant with the PEG concentration for PDMAM blends and increased with the PEG concentration for PAM systems. This result may be interpreted as a consequence of a more heterogeneous structure in PAM blends. Scanning electron microscopy micrographs of blends with 40 and 80 wt % PEG provided evidence of the regions associated with PEG crystallites. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1493–1500, 2003     

Structure and coordination properties of facilitated olefin transport membranes consisting of crosslinked poly(vinyl alcohol) and silver hexafluoroantimonate

The high selectivity of solid‐state crosslinked poly(vinyl alcohol) (CPVA) membranes containing silver hexafluoroantimonate (AgSbF₆), with respect to olefin/paraffin mixtures, was previously reported. The structure and coordination properties of CPVA/AgSbF₆ complexes were investigated in this study with wide‐angle X‐ray scattering (WAXS), differential scanning calorimetry (DSC), X‐ray photoelectron spectroscopy (XPS), and theoretical ab initio calculations, and they were compared with those of poly(vinyl alcohol) (PVA)/AgSbF₆ complexes. Contrary to expectations, the measurements of the intersegmental d‐spacings and glass‐transition temperatures indicated that the chain mobility in the PVA/AgSbF₆ membranes was lower than that in the CPVA/AgSbF₆ membranes. The different extents of transient crosslinking in the two systems were attributed mostly to their different coordination structures; silver ions in PVA/AgSbF₆ were coordinated with hydroxyl oxygens located near the polymer main chains, whereas those in CPVA/AgSbF₆ were coordinated with aldehyde oxygens located far from the main chains. According to WAXS spectra, AgSbF₆ was completely dissolved in both PVA and CPVA, and this disrupted the crystallinity of the polymers. However, our DSC study showed that the silver ions dissolved in both polymer matrices recrystallized into silver oxide at elevated temperatures. The binding energy of Ag3d_5/2, as determined from XPS spectra, shifted to lower values with the addition of increasing amounts of the polymer matrix, indicating the increasing coordination of silver ions with polymer chains. The presence of various oxygen species with and without coordination to silver ions was confirmed from O1s XPS spectra of CPVA membranes containing silver ions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 621–628, 2004     

用DSC研究线形多嵌段聚氨酯与聚氯乙烯、氯化聚氯乙烯共混相容性

用示差扫描量热法（DSC）研究了线形多嵌段聚氨酯（PU）与聚氯乙烯（PVC）、氯化聚氯乙烯（CPVC）共混相容性，说明了PU／VC、PU／CPVC的相容是由于共混物中形成了新的氢键的缘故．聚酯型聚氨酯与PVC、CPVC的相容性要好子聚酸型聚氨酯，CPVC与PU的相容性又要好于PVC．聚氨酯中硬段的引入不利于PU／PVC、PU／CPVC的相容性．     

Studies on photocrosslinkable-cum-flame retardant poly(benzylidene phosphoramide ester)s

Four series of photocrosslinkable-cum-flame retardant poly(benzylidene phosphoramide ester)s were synthesized from bis(4-hydroxy-3-methyoxybenzylidene) acetone, 2,5-bis(4-hydroxy-3-methoxybenzylidene)cyclopentanone, 2,6-bis(4-hydroxy-3- methoxybenzylidene)cyclohexanone and 2,7-bis(4-hydroxy-3-methoxybenzylidene) cycloheptanone with various arylphosphorodichloridates by interfacial polycondensation using a phase transfer catalyst. The resultant polymers were characterized by gpc, FTIR, ¹H, ¹³C and ³¹P-NMR spectroscopy. Thermal behavior of the polymers was evaluated by differential scanning calorimetry and thermogravimetry. Flame retardant properties were ascertained by Limiting Oxygen Index. The photocrosslinking ability of the polymers was studied by ultraviolet spectroscopy. The crosslinking proceeds via 2π + 2π cycloaddition reaction of the benzylidene groups. The rate of crosslinking decreases with increase in the size of cycloalkanone ring, while the thermal stability increases with increase in the size of the alkanone ring. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3285–3291, 1999     

Synthesis and characterization of novel biodegradable unsaturated poly(ester amide)s

A series of novel biodegradable unsaturated poly(ester amide)s (UPEAs) were synthesized through the solution polycondensation of two unsaturated monomers, di‐p‐nitrophenyl fumarate and L ‐phenylalanine 2‐butene‐1,4‐diol diester p‐toluene sulfonate, and four other saturated monomers in different combinations. The UPEAs were obtained in fairly good yields with N,N‐dimethylacetamide (DMA) as the solvent. The number‐average and weight‐average molecular weights of the UPEAs, measured by gel permeation chromatography, ranged from 10 to 30 kg/mol, they had a rather narrow molecular weight distribution of 1.40. The chemical structures of the novel biodegradable UPEAs were confirmed by both IR and NMR spectra. The UPEAs had higher glass‐transition temperatures than saturated PEAs of similar structures, and their glass‐transition temperatures were affected more by the CC double bond located in the diamide part than by those in the diester part. The solubility of the polymers was poor in water but better in DMA and dimethyl sulfoxide. With the availability of these inherent CC double bonds in the UPEA backbones, these UPEAs have the functionality of CC bonds, such as photochemical reactivity or the ability to react with or be modified by other bioactive or other environmentally sensitive compounds, and this can easily extend their applications to biomedical and pharmaceutical areas. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1463–1477, 2005     

Synthesis and characterization of polyamides and poly(amide-imide)s derived from 2,2-bis(4-aminophenoxy) benzonitrile

A series of polyamides and poly(amide-imide)s were prepared by the direct poly-condensation of 2,2-bis(4-aminophenoxy) benzonitrile [4-APBN] with aromatic dicarboxylic acids and bis(carboxyphthalimide)s in N-methyl-2-pyrrolidone [NMP] with triphenyl phosphite and pyridine as condensing agents. The synthesis of 4-APBN involves a nucleophilic displacement reaction in dipolar aprotic solvent with the alkali metal salt of p-aminophenol and an activated aromatic dichloro compound. Bis(carboxyphthalimide)s were prepared by condensation of 4,4^′-diaminodiphenylsulfone, 3,3^′-diaminodiphenylsulfone, 4,4^′-diaminodiphenylether, 4,4^′-diaminodiphenylmethane, 3,3^′-diaminobenzophenone, and trimellitic anhydride at a 1:2 molar ratio. The inherent viscosities of the resulting polymers were found to be in the range of 0.31-0.93 dl/g and glass transition temperatures between 235 and 298 °C. All polymers were soluble in aprotic polar solvents such as dimethylsulfoxide and NMP. The results of thermogravimetry revealed that all the polymers showed no significant weight loss before 400 °C. Wide-angle X-ray diffractograms revealed that all polymers were found to be amorphous except for the polyamide derived from isophthalic acid and polyamide-imides derived from diaminodiphenylether and diaminobenzophenone based bis(carboxyphthalimide)s.     

Hemocompatibility of poly(acrylonitrile-co-N-vinyl-2-pyrrolidone)s: swelling behavior and water states

Hemocompatibility is an essential aspect of blood contacting polymers. Knowledge of the relationship between polymer structure and hemocompatibility is important in designing such polymers. In this work, the effect of swelling behavior and states of water on the hemocompatibility of poly(acrylonitrile-co-N-vinyl-2-pyrrolidone) (PANCNVP) films was studied. Platelet adhesion and plasma recalcification time tests were used to evaluate the hemocompatibility of the films. Considering the importance of surface properties on the hemocompatibility of polymers, static water contact angles were measured by both sessile drop and captive bubble methods. It was found that, on the film surface of PANCNVP with a higher NVP content, adhered platelets were remarkably suppressed and the recalcification time was longer. The total water content adsorbed on the PANCNVP film was determined through swelling experiments performed at temperatures of interest. Differential scanning calorimetry and thermogravimetric analysis were used to probe the states of water in the films. Based on the results from these experiments, it was hypothesized that the better hemocompatibility of PANCNVP films with higher NVP contents was due to their higher free water content, because water molecule exchange at the polymer/liquid interface, facilitated by a high free water content, is unfavorable for the formation of surface bound water, which causes poor hemocompatibility. [diagram in text].