Poly(sulphopropylbetaines): 1. Synthesis and characterization

The synthesis of aromatic and aliphatic poly(sulphopropylbetaines) is described within the series of vinylpyridines and tertiary amino-methacrylates. Two complementary strategies were used: (a) preparation and free radical polymerization in aqueous solution (60°C, 4,4'-azobiscyanovaleric acid) of the monomers; (b) heterogeneous quaternization of preformed poly(vinylpyridines) and poly(tertiary amino-methacrylates) by 1,3-propanesultone in propylene carbonate or tetramethylene sulphone solution (120°C). The high molecular weight poly (zwitterions) ($\text{10}{}^5\text{<}\text{M}\text{?}{}_{\mathrm{W}}\text{< 5 × 10}{}^6$) were characterized by ultra-violet and ¹H nuclear magnetic resonance spectroscopy, and their water affinity at 20°C was estimated by water vapour absorption measurements.     

Properties of aqueous salt solutions of poly(vinylpyrrolidone). II. Polymer dimensions and thermodynamic quantities

The unperturbed dimensions and thermodynamic parameters of poly(vinylpyrrolidone) (PVP) have been studied in aqueous salt solutions, e.g. phosphates, mono- and dihydrogen phosphates, carbonates, sulphates of sodium and potassium. Values of K₀ ( = [η]_ΘM^-1/2, where [η]_Θ is intrinsic viscosity at the theta temperature and M is molecular weight) with M_w = 78 000 g mol^-1 were found to range from 4·63×10^-4 to 5·56×10^-4 dl g^-1, and root-mean-square end-to-end distances, 〈r²〉₀^1/2, ranging from 1·61×10^-6 to 1·68×10^-6cm were evaluated. Values of the characteristic ratio, C_n, the steric parameter, σ, and the enthalpy and the entropy of dilution parameters, χ_H and χ_S, have also been calculated, and the interaction parameter was found to be χ-0·5<-0·001 for aqueous salt solutions of PVP. ©1997 SCI     

Solubilities,viscosities and unperturbed dimensions of poly (2,6-diisopropylphenyl methacrylate)

The dilute solution properties of poly(2,6-diisopropylphenyl methacrylate) (PDPP) in various solvents were studied by viscosity, exclusion chromatography and osmotic pressure measurements. The Mark-Houwink-Kuhn-Sakurada relationships were established. The unperturbed dimensions, the rigidity factor σ, the characteristic ratio C∞ and the thermodynamic parameters were determined using the Stockmayer-Fixman equation and from data in theta solvent (binary mixture). The rigidity factor of PDPP is abnormally high. The conformational behaviour of this polymer is analysed in terms of the effect of the side chain structure. The results are compared with other polymers of the same series.     

Poly(sulphopropylbetaines): 4. Binding properties towards reporter anionic probes and local polarity close to the zwitterionic chain in aqueous solution

The binding properties of a representative poly(sulphopropylbetaine) towards a series of optical (methyl orange (MO) and 2-(4′-hydroxybenzenazo)benzoate (HABA)), fluorescent (8-anilinonaphthalene-1-sulphonate (ANS)) and chemically reactive (6-nitrobenzisoxazole-3-carboxylate (S)) anionic probes have been studied in dilute aqueous solution. The slight ultra-violet spectra modification for MO and HABA, the enhanced fluorescence of ANS and the moderate increase of the decarboxylation rate of S induced by the poly(zwitterion) show that binding of the various anionic probes to the macromolecular chain actually occurs through specific ion-dipole interactions, but that the intrinsic properties of the bound species are only weakly modified with respect to those of the free ones. Dehydration of the bound probe is very limited, and the polarity of its microenvironment close to the polymer chain is analogous to that of methanol. In spite of a relatively weak expansion, the poly(zwitterion) coil does not show microdomains of definite hydrophobicity.     

Dilute solution properties of poly(2-methoxycyanurate) of bisphenol F and bisphenol A

Poly(2-methoxycyanurate) of bisphenol F and bisphenol A (PMCBFA) was synthesized and fractionated by a fractional precipitation method. The fractions were characterized by viscometry, osmometry and gel permeation chromatography. The Mark–Houwink–Kuhn–Sakurada (MHKS) parameters were established in four solvents and at four different temperatures. The unperturbed dimensions and their coefficients in different solvents were computed using the Stockmayer–Fixman excluded volume theory. From the solution study it was found that PMCBFA is highly flexible. This may be due to the ether linkage present in the main chain.     

Viscosity Behaviour of Poly(N-vinyl-2-pyrrolidone) in a Water/VOSO4 Binary Mixture: Preferential Interactions

Poly(N-vinyl-2-pyrrolidone) (PVP) [2]/water [1]/VOSO₄ [3] ternary system interactions have been studied by viscometric and densitometric techniques. Preferential water absorption inside the macromolecular coil and preferential salt interaction with the polymer external domain were observed. The unperturbed dimensions of the macromolecule increased with the salt concentration up to 75mM VOSO₄, a point where the intrinsic viscosity was also a maximum and a conformational transition could be produced. The polymer– solvent interaction became worse with salt concentration and VOSO₄ behaved as a salting-in agent for the polymer, the binary solvent mixture being thermodynamically unfavourable. © of SCI.     

Poly(L‐lactide): v. effects of storage in swelling solvents on physical properties and structure of poly(L‐lactide)

The effects of storage at 25°C in swelling solvents having different solubility parameter (δ_s) values of 16.8–26.0 J^0.5 cm^−1.5 on the physical properties and structure of as‐cast poly(L ‐lactide) (PLLA) films was investigated by the degree of swelling (DS), differential scanning calorimetry (DSC), and tensile tests. It was found that PLLA film shows durabity to swelling solvents having δ_s values much lower or higher than the value range of 19–20.5 J^0.5 cm^−1.5 and that the polymer solubility parameter (δ_p) for PLLA is in the value range of 19–20.5 J^0.5 cm^−1.5. The decrease in the glass transition temperature (T_g) and tensile properties and the increase in melting temperature (T_m) and crystallinity (x_c) were larger for PLLA films swollen in solvents having a high DS at 7 days (DS_7days). The slight increase in T_m and x_c for PLLA films after swelling in solvents with high DS_7days values was due to the crystallization of PLLA that occurred during swelling, while the small increase in T_g and elongation at break (ε_B) for PLLA films after immersion in the solvents having low DS_7days values was ascribed to stabilized chain packing in the amorphous region. The T_g, ε_B, and Young's modulus of the PLLA films after swelling in the solvents varied in the ranges of 47–57°C, 4–8%, and 55–77 kg/mm², depending on their DS_7days or δ_s values. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1582–1589, 2001     

Solution properties of poly(thiocarbonates) containing cyclic side chains

Poly(thiocarbonates) with cyclic side chains have been studied in the theta solvent 1,4-dioxane. The Mark-Houwink-Sakurada (MHS) relationships were established and the unperturbed dimensions determined. The conformational parameters were compared with those of other poly(thiocarbonates) and related polymers. It was found that the polymers containing cyclic groups present a more extended and rigid chain. A marked influence of the nature and structure of the side chain on the conformational parameters was found.     

Blends of poly(ether imide) and an aromatic poly(ether amide): Phase behavior and CO2 transport properties

Blends of poly(ether imide) (PEI, Ultem 1000) and an aromatic poly(ether amide) were studied. Although homogeneous or heterogeneous blends can be obtained depending on the blend preparation method, the inherent miscibility of the mixture was finally established. The so-called enthalpy relaxation method was used to detect one or two glass transition temperatures in the blends in spite of the similarity of the pure component transitions. Fourier transform infrared analysis provided additional evidence of the specific interactions, which could be in the origin of the miscibility. A preliminary study of the influence of the homogeneity level in the transport properties of the blend films was also undertaken. Carbon dioxide at 1 bar was used as a penetrant. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 2141–2149, 1998     

含聚氧乙烯链端树枝状聚（胺-酯）的合成及性能

以端基为8个伯氨基的树枝状化合物〔PAE(NH2)8〕和聚氧乙烯〔PEO-A(454)〕或丙烯酸钠(SAA)与聚氧乙烯为原料合成了含聚氧乙烯链端树枝状聚(胺-酯)(PAE-PEO-A和PAE-SAA-PEO-A)。通过正交实验讨论了反应温度、反应时间及原料配比对产物产率的影响,并用FTIR、1HNMR、13CNMR及GPC对试样进行结构表征。测定了含聚氧乙烯链端树枝状聚(胺-酯)的表面张力及对苯甲酸、水杨酸的增溶性。实验结果表明,当反应温度为65℃,反应时间为96 h,原料的配比量n〔PAE(NH2)8〕∶n[(PEO-A(454)]=1∶16,以甲醇为溶剂,产物产率为88.30%。PAE-PEO-A溶液的临界胶束质量浓度为0.007 5 g/L,最小表面张力为43.8 mN/m。PAE-PEO-A对苯甲酸、水杨酸都有增溶性,且增溶能力随着它们的表面官能团数的增多和浓度的增加而增大。当反应温度为50℃,反应时间为96 h,原料的配比量n〔PAE(NH2)8〕∶n(SAA)∶n〔PEO-A(454)〕=1∶12∶8,以甲醇为溶剂,产物产率为48.83%。PAE-SAA-PEO-A水溶性极好,其表面张力与水接近,几乎不具有表面活性。PAE-SAA-PEO-A对苯甲酸和水杨酸有良好的增溶性,尤其是对水杨酸的增溶性明显。在相同质量浓度0.500 g/L时,PAE-SAAPEO-A对水杨酸的增溶量约为PEG-400的2.4倍。     

Preferential interactions of poly(N-vinyl-2-pyrrolidone) in the binary mixture water/CdCl2

The poly(N-vinyl-2-pyrrolidone)(PVP)(2)/water(1)/CdCl₂(3) ternary system has been studied by viscometry, densimetry and atomic absorption spectrophotometry. In this system a preferential adsorption of Cd²⁺ at all solvent compositions studied and a conformational transition at 4mM of salt, the concentration at which a preferential adsorption minimum of Cd²⁺ in exhibited, are observed. The PVP/Cd²⁺ bound molar ratio is 0·23. CdCl₂ behaves as a salting-in agent for the macromolecule. The binary solvent mixture is thermodynamically more favourable at salt concentrations greater than 10 mM of CdCl₂.     

Complexation of poly(vinylpyrrolidone) and gelatin with some transition metal chlorides in aqueous solution

Complexation of poly(vinylpyrrolidone) and gelatin with certain metal chlorides (HgCl₂, CdCl₂, CoCl₂, and ZnCl₂) have been investigated by viscosimetric and spectrophotometric techniques in aqueous solutions. While the change in intrinsic viscosity, [η], of poly(vinylpyrrolidone) has shown a discontinuity with a concentration of metal chlorides, gelatin showed a steady decrease with increasing metal chloride concentration. The decreasing order of effectiveness of cations in complex formation is Hg²⁺ > Cd²⁺ > Co²⁺ > Zn²⁺ for poly(vinylpyrrolidone) and Zn²⁺ > Co²⁺ > Cd²⁺ > Hg²⁺ for gelatin solutions. It has been suggested that the poly(vinylpyrrolidone)/metal cation interaction is a charge-controlled reaction, and gelatin/metal cation is a covalent coordination in character. A similar metal cation effect has been observed for poly(vinylpyrrolidone) by UV-VIS spectrophotometry. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 891–895, 1998     

Poly(propylene) composite with hybrid nanofiller: Dynamic properties

Mechanical, impact, and relaxation properties of in situ synthesized carbon nanotubes‐polyaniline (CNT‐PANi) hybrid nanoparticle‐filled poly(propylene) (PP) composites with or without an amphiphilic dispersing agent were investigated using tensile testing, notched Charpy impact testing, and dynamical mechanical testing methods. The reference material was MWCNT filled PP composite. Ethyl gallate (EG) was the dispersing agent which realizes high conductivity in PP composites with hybrid filler. Measured properties showed quite similar behavior of CNT‐PANi hybrid and neat CNT filled composites. Addition of 20% EG in PP did not cause essential differences compared to the neat PP. When the dispersing agent was added in filler containing PP composites, remarkable effects were observed, especially in PP‐hybrid composites. Mechanically, these materials had improved tensile properties, but they were brittle compared to the materials without dispersing agent. Dynamic mechanical analysis showed improvement in storage modulus, and in loss modulus the α transition was well observable. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Fabrication of Uniaxially Aligned Poly(propylene) Nanofibers via Handspinning

A straightforward method, which is termed novel handspinning, is reported for producing uniaxially aligned sPP nanofibers. As demonstrated by SEM analysis, the morphologies of handspun sPP nanofibers are strongly dependent upon the processing conditions such as spinning method and solvent system. Compared to the normal electrospun sPP nanofibers, the handspun sPP nanofibers show smoother morphologies. FT‐IR analysis demonstrates a significant difference in polymer chain conformation between the handspun and electrospun sPP nanofibers. Moreover, interestingly, the handspun sPP single nanofibers show higher Young's modulus and tensile strength than electrospun sPP single nanofibers.

     

In‐Situ Fiberized Poly(ethylene terephthalate) as a Reinforcement to Poly(propylene) Matrix

The reinforced poly(propylene) (PP)/poly(ethylene terephthalate) (PET) in‐situ fiberized composites were prepared by extrusion‐drawing‐injection molding. The influences of PET weight fraction (f_w) on the PET fiberization, phase morphology, and mechanical properties of the composites, together with their functional mechanisms were studied by contrast to the normal‐blended materials without drawing. The results show that as the f_w rises from 0 to 20%, the number of PET fibers increases, whereas their diameter and dispersity decrease till f_w = 15% and then increase, and the number of remained PET particles tends to rise. These changes of PET fiberization and phase morphology with f_w were attributed to the consequence of the combined actions of breakup, coalescence, and deformation of the PET dispersed phase in the PP matrix during the extrusion drawing. Correspondingly, the tensile strength (σ_t) and Young's modulus (E) of the in‐situ composites increase till f_w = 15% and then decrease, with maximum gains of σ_t and E of about 20 and 70% relative to the neat PP, respectively. This σ_t/f_w relation was ascribed to the counterbalanced result between the reinforcing effect of the dispersed phase on matrix and the interfacial flaw effect of two immiscible phases, while the E/f_w relation was considered as a representation of the rigidizing effect of the fibers on the matrix being controlled by both their number and diameter.

In‐situ PET fibres (PET/PP = 85/15) in an as‐drawn filament.     

Poly(ether ether ketone)/poly(aryl ether sulfone) blends: Relationships between morphology and mechanical properties

Mechanical properties such as the tensile modulus, yield (break) strength, and elongation to break (or yield) are measured for multiphase poly(ether ether ketone) (PEEK)/poly(aryl ether sulfone) (PES) blends. Specimens with three different levels of thermal histories (quenched, as‐molded, and annealed) are prepared in order to study their effects on the mechanical properties of PEEK/PES blends. Synergistic behavior is observed in the tensile modulus and tensile strength of the blends in almost the whole range of compositions. The ductility of quenched blends measured as the elongation to break (yield) shows an unexpected synergistic behavior in the blend containing 90 wt % PEEK, although a negative deviation from additive behavior is observed in the rest of the compositions. A ductile–brittle transition is observed between 50 and 75 wt % PEEK in the blend. The ductile–brittle transition in as‐molded blends shifts to 75–90 wt % PEEK. Annealed blends show predominantly brittle behavior in the whole composition range. The experimental data are further correlated with the theoretically predicted results based on various composite models. Although the prediction based on these equations fails to fit the experimental data in the whole composition range, the simplex equations that are normally used for blends showing synergistic behavior produced a reasonable fit to the experimental data. The mechanical properties obtained for different blend compositions are further correlated with their morphology as observed by scanning electron microscopy. Morphological observation shows a two‐phase morphology in PES‐rich blends, which is an interlocked morphology in which the disperse phase is not clearly visible in PEEK‐rich blends, and a cocontinuous type of morphology for a 50/50 composition. Considerable permanent deformation of both the disperse and matrix phase, especially in the case of quenched tensile specimens, demonstrates the remarkable adhesion present between the two phases. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2887–2905, 2003     

Poly(2-hydroxyethylmethacrylate-co-2-folate ethylmethacrylate) and Folic acid/Poly(2-hydroxyethylmethacrylate) Solid Solution: Preparation and Drug Release Investigation

Poly(2-hydroxyethylmethacrylate-co-2-folatethylmethacrylate) was synthesized by free radical polymerization of 2-hydroxyethylmethacrylate with 2-folatethylmethacrylate and folic acid/poly(2-hydroxyethylmethacrylate) solid solutions was prepared by mixing folic acid with poly(2-hydroxyethylmethacrylate) using the solution casting method. The structure and the homogeneity distribution of folic acid in the polymer matrix are characterized by different methods. The diffusion behaviors of water and folic acid through poly(2-hydroxyethylmethacrylate-co-2-folatethylmethacrylate) and poly(2-hydroxyethylmethacrylate) matrixes were found obey to the Fick models. The in vitro cytotoxicity assessed by microculture tetrazolium test assay and the antioxidant activity of poly(2-hydroxyethylmethacrylate-co-2-folatethylmethacrylate) systems determined by 1,1-diphenyl-2-picryl-hydrazyl method revealed no significant toxicity of these systems and has excellent free radical scavenger property which can be as safe candidate in drug-carrier system. The solubility enhancement of folic acid in different pH media is also investigated and the results obtained reveal a maximum of 399–400?mg?L^?1. The release dynamic of folic acid from the poly(2-hydroxyethylmethacrylate-co-2-folatethylmethacrylate) containing 5?mol% of folic acid and that from folic acid/poly(2-hydroxyethylmethacrylate) system containing 10?mol% of folic acid have the best intestine/stomach ratio.     

Multiple transitions in poly(allylbenzene): 1. Thermophysical properties

Polyallylbenzene is a semicrystalline material the thermal behaviour and physical properties of which reveal several transitions. Thermal and differential calorimetric analysis have shown the influence of the history of the material about the glass transition and melting. Several techniques such as thermomechanical analysis, dilatometry and inverse gas chromatography give additional information for the unidimensional and volume behaviour of the polymer versus temperature.     

Measurement of the unperturbed dimensions of stereoregular poly(methyl methacrylate)

The results of measurements of unperturbed dimensions for a series of stereoregular poly(methyl methacrylates) are reported. The measurements were made by a recently developed method involving a gel permeation chromatograph coupled with an on-line low angle laser light scattering photometer. Measurements were performed in a thermodynamically good solvent, tetrahydrofuran at 25°C. The unperturbed dimensions were obtained by means of viscosity plots. Comparison of the results obtained by this method with those currently available in the literature, as well as with values predicted by statistical calculations, show good agreement. It was determined that a measurable difference occurs in the Mark-Houwink relationship between isotactic and syndiotactic poly(methyl methacrylate); isotactic poly(methyl methacrylate) is 30% more extended than syndiotactic poly(methyl methacrylate) in its unperturbed state; and isotactic poly(methyl methacrylate) exhibits a smaller degree of polymer solvent interaction than the syndiotactic form.     

Molecular simulations of the conformational properties of atactic poly(2-ethylbutyl methacrylate)

RIS Metropolis Monte Carlo (RMMC) simulations were used to determine the unperturbed theta-state chain dimensions of atactic stereoconfigurations of poly (2-ethylbutyl methacrylate) [PEBMA]. Root mean-squared end-to-end distance (〈r²〉_o/M)^1/2 and characteristic ratio (C_n) were calculated along with the backbone torsion angle distribution. The simulated properties are in very good agreement with experimental results. The values of the PEBMA chain dimensions are in-between those corresponding ones for poly(n-butyl methacrylate) and poly (n-hexyl methacrylate) thereby showing the effect of branching in the side-chain. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012