Terms Of Solubility Parameters Research Articles

The Effect of Nanosilicates on the Performance of Polyethylene Terephthalate Films Prepared by Twin-Screw Extrusion

Abstract Polyethylene terephthalate (PET) films were prepared by cast extrusion using a twin-screw extruder with a severe screw profile. The effect of an organically modified montmorillonite on thermal, mechanical, optical, and barrier properties of the PET films were investigated. Morphological characterization of the nanocomposite films was performed by employing wide angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) followed by image analysis. The results unfold a mixed morphology for the nanocomposite films with more than 95% exfoliated and intercalated silicate layer structures, depending on the screw rotation speed. The remarkable dispersion of the organoclay particles at the nano-level is discussed in terms of solubility parameter and favorable interactions between PET macromolecules and organic modifier of the nanoclay. The crystal content of the nanocomposite films and their cold and hot crystallization temperatures confirmed the role of silicate nanolayers as a heterogeneous nucleating agent. While all nanocomposite films exhibit higher haze values in comparison to the neat PET samples, incorporation of 2 wt% nanoclay brought about 25% increase in tensile modulus and barrier properties. A range of screw rotation speeds with optimized properties in terms of haze, morphology, thermal, mechanical, and barrier properties is suggested.

Solvent and non-solvent selection for the chemical recycling of waste Polyethylene (PE) and Polypropylene (PP) metallized film packaging materials

A solvent and non-solvent selection method for the chemical recycling through selective dissolution and precipitation of multi-component waste metallized film wrapper is studied to recover Polyethylene (PE), Polypropylene (PP), and the metal film separately. Pre-selection of solvent for dissolution and non-solvent for precipitation is based on the similarity and compatibility of polymer and solvent molecules measured in terms of solubility parameter and calculated using group contribution approach through Hoftyzer and Van Krevelen method. Toxicity, cost, and availability of the solvent are also considered on the selection. A Hansen sphere model is developed for the prediction of polymer solubility in which p-cymene, a low-cost and naturally derived solvent is chosen as solvent and acetone as non-solvent. PE was first recovered through dissolution at a given temperature, followed by precipitation. PP which remained undissolved together with the metal film was extracted through the same technique but with different dissolution temperature. FTIR spectra of the recovered polymers showed similarity compared to virgin PE and PP films. The melting point of the recovered PE and PP using p-cymene determined in the DSC curves were 107.37 °C and 164.55 °C, respectively. Furthermore, the simplicity of the process, high recovery yield obtained, and the application of p-cymene would make the recycling economical and environment-friendly.

Effects of Solvents on Stereocomplex Crystallization of High‐Molecular‐Weight Polylactic Acid Racemic Blends in the Presence of Carbon Nanotubes

AbstractStereocomplex (SC) crystallization of solution‐casted high‐molecular‐weight polylactic acid/carbon nanotube (CNT) composites is investigated under the effects of solvents, including dichloromethane (CH2Cl2), chloroform (CHCl3), N,N‐dimethylformamide (DMF), and 1,4‐dioxane (DIOX). It is found that addition of 0.1 wt% CNTs can promote the SC formation in the equimolar poly(l‐lactic acid) (PLLA)/poly(d‐lactic acid) (PDLA) blends. More interestingly, the final content of SC crystallites is mediated by solvent species to a large extent. Results of wide‐angle X‐ray diffraction and differential scanning calorimetry reveal that the capability of solvents for enhancing the SC content in PLLA/PDLA/CNT composites follows the sequence: DMF > DIOX > CHCl3 > CH2Cl2. Especially, exclusive SC crystallites are formed in the DMF. Such a disparity is explained in terms of solubility parameter and vapor pressure of the solvents. The above results also provide the possible solution to regulate the crystalline composition of the PLLA/PDLA/CNT blends, by which the expected performance may be obtained.

Template-Free Electrodeposition of Uniform and Highly Crystalline Tin Nanowires from Organic Solvents Using Unconventional Additives

High-areal-density Sn nanowires (NWs) with diameter of ≥25nm and length of several micrometers (>103 aspect ratio) were successfully prepared via template-free electrodeposition from organic solutions containing SiCl4 and an ionic liquid (IL). This study shows that the presence of both IL and SiCl4 in the electrolyte is necessary to obtain structurally well-defined NWs. Electron microscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy demonstrate that the NWs consist of high-quality β-Sn crystallites and the morphology is homogenous over large deposition areas. It is also shown that various organic solvents such as propylene carbonate and acetonitrile as well as different types of ILs as supporting electrolytes in combination with SiCl4 can be used for the preparation of Sn NWs. This makes the electrochemical synthesis flexible in terms of solubility parameter and less costly than deposition from pure ILs. The Sn NWs were also tested for application in rechargeable Li-ion cells by galvanostatic cycling against Li metal. The electrodes were found capable of delivering stable specific capacities of around 680mA h gSn−1 at C/5 over several cycles.

Fabrication and structural tuning of novel composite hollow fiber membranes for pervaporation

ABSTRACTA series of polysiloxaneimide (PSI)/polyetherimide (PEI) composite hollow fibers were fabricated by coextrusion and phase inversion. The hydrophobic PSI outer layer was set as the selective layer which was supported by the PEI inner layer. The PSI was synthesized by polycondensation of 3,3′,4,4′‐Biphenyltetracarboxylic Dianhydride (BPDA) with amino siloxane X‐22‐161A and a chain extender, 1,3‐Bis (3‐aminopropyl) −1,1,3,3‐tertramethyldisiloxane (BATS). It was found that the macroscopic uniformity of PSI layer was dependent on the dope formulation, coagulant composition and dope flow rate: (1) the higher similarity degree of the solvent(s) for different layers in terms of solubility parameters, (2) the utilization of surfactant as a component in the water coagulant, and (3) higher flow rates of the outer layer dopes, led to the formation of more uniform and smoother PSI outer layer. The maximum outer layer thickness was around 2 μm. The bulk of the PEI layers were porous with finger like macrovoids. The outer surface of the inner PEI layer for some batches of the hollow fibers was confirmed to be porous. The original dual‐layer hollow fibers showed poor pervaporation performance. Post treatment was applied to cure the hollow fiber, delivering composite membranes with performance dominated by the coating material of PDMS. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43324.

Measurement and correlation of deferiprone solubility: Investigation of solubility parameter and application of van't Hoff equation and Jouyban–Acree model

The available solubility of deferiprone (DFP) in mono and mixed solvent systems is limited. The aim of this work is to find solvation of DFP with respect to the composition of the solvent mixture. Solubility of DFP in water, ethanol (EtOH) and N-methyl-2-pyrrolidone (NMP) was experimentally determined at 293.2, 298.2, 303.2, 308.2 and 313.2K. Its solubility in aqueous binary mixtures of EtOH and NMP was also investigated. Solubility of DFP in aqueous binary solvent mixtures of ethylene glycol (EG), propylene glycol (PG) and polyethylene glycol 400 (PEG 400) and non-aqueous binary solvent mixtures of EG+EtOH, EG+NMP, EG+PG and EG+PEG 400 is investigated and solubility profile shape of each system is explained in terms of solubility parameter. Total solubility parameter of DFP is calculated by Fedor's group contribution method and compared to solubility parameter of various solvent mixtures in order to estimate maximum solubility in specific co-solvent ratio.Based on the generated experimental solubility data, trained versions of the van't Hoff and Jouyban–Acree models were used to simulate DFP solubility in the binary mixture compositions. The applicability of the thermodynamic model to predict the solubility of DFP was studied. The experimental data was used to provide accurate estimations of solubility in the investigated solvent systems using van't Hoff and Jouyban–Acree equations.

Solubility parameter-based analysis of polyacrylonitrile solutions in N,N-dimethyl formamide and dimethyl sulfoxide

The physical properties of the solutions of polyacrylonitrile (PAN) in N,N-dimethyl formamide (DMF) and dimethyl sulfoxide (DMSO) were characterized in terms of solubility parameter. The physical properties were largely determined by individual solubility parameters, particularly the polar term, rather than overall solubility parameter. With increasing temperature, the intrinsic viscosity and hydrodynamic diameter of dilute solutions were decreased but the dynamic viscosity (η′) of concentrated solutions was increased. Of the two solvents, these phenomena were more pronounced with DMF; DMF gave greater η′ and yield stress than DMSO. When the polymer solutions were dried at 25 °C DMSO generated a cocontinuous structure whereas DMF produced a dispersed morphology. In addition, DMF dissolved PAN faster than DMSO, and the dissolution process followed a mechanism analogous to SN2 reaction.

Effect of the polar modifiers on supercritical extraction efficiency for template removal from hexagonal mesoporous silica materials: Solubility parameter and polarity considerations

The introduction of polar modifiers usually can make supercritical CO2 extraction more attractive in various potential applications. In this work, modified supercritical CO2 extraction of the dodecylamine template has been performed on freshly synthesized mesoporous HMS materials with the use of 10 different polar modifiers. The effects of the polar modifiers on the extraction efficiencies of the amine template and structural properties of resultant HMS materials have been investigated in detail. Among the ten modifiers used, formic and acetic acids, water and methanol give reasonably high extraction efficiencies and the effects of the modifier identity on extraction efficiencies have been discussed in terms of solubility parameter and dipole moment of the modifiers. Methanol seems to be much better than the other modifiers for the SCCO2 extraction of dodecylamine from HMS materials since the resulted materials have well preserved highly ordered mesoporous structure and possessed much large specific surface area and pore volume as reflected by XRD spectra and nitrogen adsorption/desorption results.

Effects of polar modifiers on supercritical extraction efficiency for organic template removal from mesoporous MCM-41 materials

The application of polar modifiers usually can make supercritical CO2 extraction more attractive in various potential applications. In this work, several polar modifiers have been examined for the extraction of the template cetyltrimethylammonium bromide (CTMABr) from newly synthesized MCM-41 mesoporous materials, and the modifier content, modifier identity and the sample matrix on supercritical CO2 extraction efficiency are then evaluated. The results show that the polar modifiers employed have strong influences on the template extraction efficiencies and this could be interpreted rather well in terms of solubility parameter and polarity of the modifiers. Methanol, water and acidic methanol are found to result in very high efficiencies of more than 85% for the pure siliceous samples while relatively good extraction efficiencies of 60–80% for aluminum incorporated samples, and the difference is due to that the organic template could form stronger interactions with the Al species than the silanol groups. Nitrogen adsorption/desorption and X-ray diffraction results confirmed that the polar modifiers have strong influences on the final mesoporous structure of the MCM-41 materials and with methanol modified supercritical CO2 extraction the resultant materials possess well-ordered mesostructure and much better structural properties like higher pore volume and specific surface area.

Evaluation of solubility in simulated lung fluid of metals present in the slag from a metallurgical industry to produce metallic zinc

The objective of this study was to determine the solubility parameters (rapid and slow dissolution rates, rapid and slow dissolution fractions) for nickel, cadmium, zinc and manganese compounds present in a pile of slag accumulated under exposure to weathering. This slag was generated by a metallurgical industry that produced zinc and zinc alloys from hemimorphite (Zn4(OH)2Si2O7.H2O) and willemite (Zn2SiO4) minerals. A static dissolution test in vitro was used to determine the solubility parameters and Gamble's solution was used as the simulated lung fluid (SLF), on a time basis ranging from 10 min to 1 year. The metal concentrations in the slag samples and in the SLF were determined using Particle Induced X-rays Emission (PIXE). There are significant differences in terms of solubility parameters among the metals. The results indicated that the zinc, nickel, cadmium and manganese compounds present in the slag were moderately soluble in the SLF. The rapid dissolution fractions of these metals are associated with their sulfates. In conclusion, this study confirms the harmful effects on the neighboring population of the airborne particles containing these metals that came from the slag.

Experimental Determination of Hansen Solubility Parameters for Select POSS and Polymer Compounds as a Guide to POSS–Polymer Interaction Potentials

Polyhedral oligomeric silsesquioxanes (POSS) have been incorporated into a wide range of polymers over the past two decades in an attempt to enhance their thermal and mechanical properties. Properties of POSS/polymer blends/composites are highly dependent on the uniformity of POSS dispersion and thus are particularly sensitive to the magnitude of interaction between POSS and added fillers/polymers. Methods to characterize these interactions in terms of solubility parameters have been recently examined in the literature using group contribution calculations. The present work presents a method for measuring three-dimensional Hansen solubility parameters for polymers and POSS which allows for the direct calculation of interaction potentials. These measured solubility parameters predict POSS/polymer interactions more accurately than group contribution calculations and accurately predict the uniformity of POSS dispersion and the resultant property enhancements.

Compatibility of diazepam with polypropylene multilayer infusion container

Techflex®, a polypropylene-lined, multilayer infusion bag, was studied for its compatibility with diazepam, in comparison to the conventional infusion bag, Safeflex®, which is comprised of poly(vinyl chloride) (PVC). Diazepam was diluted in 0.9% sodium chloride isotonic solution and stored in the infusion bags for 24 h. To evaluate the sorption of diazepam into the infusion bags during storage, the concentration of the drug remaining in the bag was measured using gas chromatography-mass spectroscopy. The PVC bags exhibited a marked sorption of diazepam, with a drug loss reaching up to 90% of the initial concentration after 24 h of contact, whereas Techflex® inhibited the drug sorption, showing approximately 10%, under the same conditions. The differences in the sorption behaviors of the bags are discussed in terms of solubility parameters and crystallinities of the polymers.

Miscibility, mechanical and thermal properties of poly(lactic acid)/polyester-diol blends

We found new plasticizers with high molecular weight and low mobility for poly(lactic acid) (PLA). The new plasticizers are polyester-diols (PED) with nominal molecular weight 2000. Temperature dependence of oscillatory tensile moduli of PLA/PED blends in solid states was measured and miscible pairs of the blends were found. The miscible pairs are PLA/poly(ethylene adipate) and PLA/poly(diethylene adipate). Observation by scanning electron microscope and results of differential scanning calorimetry also indicate that these blends are miscible with PLA at weight ratio of PED less than or equal to 20%. In these blends, glass transition temperature is significantly lower than that of PLA. On the other hand, poly(butylene adipate) and poly(hexamethylene adipate) are partially miscible with PLA at weight ratio of PED 20%. The difference of the miscibility is discussed in terms of solubility parameter, which is calculated using the method by Small and configurational entropy.

Characterisation and vapour sensing properties of spin coated thin films of anthracene labelled PMMA polymer

In the present article thin films of poly (methyl methacrylate) (PMMA) polymer labelled with anthracene (Ant-PMMA) prepared by spin coating are characterised by UV–visible spectroscopy, surface plasmon resonance (SPR), spectroscopic ellipsometry (SE) and Atomic Force Microscopy (AFM) and their organic vapour sensing properties are investigated. Ant-PMMA films' thickness are determined by performing theoretical fitting to experimental data measured using SPR and SE. Results obtained show that the spin-cast films are of good uniformity with an average thickness of 6–8 nm. Organic vapour sensing properties are studied using SPR technique during exposures to different volatile organic compounds (VOCs). Ant-PMMA films' response to the selected VOCs has been examined in terms of solubility parameters and molar volumes of the solvents, and the films were found to be largely sensitive to benzene vapour compared to other studied analytes.

The Influence of Flexible Segments on Liquid Crystalline Properties in Terms of Solubility Parameters. An Attempt at Quantitative Interpretation

The phase behavior of some rodlike block molecules has been reviewed with reference to the polarity of constituent segments. It was found that the ability of the mesophase formation is connected with differences in polar character between the flexible chains and rigid cores. Thus the polar poly(oxyethylene) group connected with the polar rigid core reduces mesophase stability but is advantageous when put together with some apolar building blocks. An attempt at quantitative estimation of the incompatibilities of different parts of molecules by means of Hansen solubility parameters delta and Flory interaction parameters chi has also been made. On the basis of chi parameters the Gibbs free energies of mixing of these segments were calculated. The changes of Gibbs free energy reflecting the compatibility of segments and their tendency to the phase separation and the volume fraction of mesogenic rigid core reflecting their ability to arrangement in one direction appear to be crucial in terms of type of the mesophase formation.

Modification of poly(vinyl alcohol) membranes for pervaporative separation of benzene/cyclohexane mixtures

Poly(vinyl alcohol) (PVA) was chemically modified by acid-catalysed acetalisation, resulting in the formation of poly(vinyl acetal) (PVAc). The addition of a molecular recognition compound, namely, O, O-bis(diethoxyphosphoryl)- tert-butyl calixarene (calix) to the PVA sol, yielded the morphologically modified membranes, designated as PVA–calix. These membranes were characterised using spectroscopic and thermoanalytical techniques, and also tested for their chemical resistance, mechanical strength and pervaporative behaviour towards benzene (Bz)/cyclohexane (Chx) mixtures. The polymers were found to be selective towards Bz. When evaluated against pure Bz and Chx at 27±1 °C; PVA–calix showed an ideal selectivity tending towards infinity but a poor flux (5.9 kg μm/(m 2 h)) for Bz. The flux of Bz was significantly higher in PVAc and increased from 20 kg μm/(m 2 h) for 20% (v/v) Bz/Chx mixture to 65.8 kg μm/(m 2 h) for pure Bz. The swelling index also increased with the increasing concentration of Bz in the feed. Pervaporation in PVAc was thus sorption-controlled. The sorption isotherms for the pure components in PVAc were also obtained using an automated sorption analyser based on the principle of mass relaxation of the polymer accompanying vapour sorption. The high interaction of PVAc with Bz was interpreted in terms of solubility parameters and free volume in the polymer.

Towards the simulation of poly(vinyl phenol)/poly(vinyl methyl ether) blends by atomistic molecular modelling

Molecular simulations of poly(vinyl phenol)/poly(vinyl methyl ether) (PVPh/PVME) blends were performed and their degree of miscibility evaluated as a preliminary step before orientation simulations. A minimum of three periodic boundary condition amorphous models was constructed and analysed in terms of solubility parameter, X-ray pattern, pair correlation function, hydrogen bond fraction and backbone conformation. The values obtained are consistent with miscibility of the systems, although it is suggested that the degree of mixing is not uniform for the different models.

Enthalpic, Entropic, and Square Gradient Contributions to the Surface Energetics of Amine-Cured Epoxy Systems

The evolution of surface tension during polymerization of three amine-cured epoxy systems was investigated. Due to the chemical reaction of the epoxy groups with primary and secondary amines, the energetic status of an epoxy–amine system increased during polymerization. At the same time, the polymerization process induced entropic variations, also contributing to the evolution of surface energetics. A simple relation expressing the surface tension as a function of the bulk energy, the entropy of the system, and the square gradient of the polymer density was derived. The bulk and surface energetics were expressed in terms of solubility parameter and surface tension, respectively. The former was predicted using the Van Krevelen group contribution method, while the latter was directly measured using the Wilhelmy wetting method. Results indicated that, in all the three epoxy–amine systems under investigation, a unique relationship combining the surface tension, the bulk energy, the entropy, and the density square gradient of the system could be used. On the basis of the present study, and taking into account all contributory factors, it was concluded that the enthalpy component to the surface energetics is the dominant contribution.

Flocculation Onset Titration of Petroleum Asphaltenes

The abundantly used technique of flocculation onset titration (FT) of asphaltenes is investigated, and it is shown how additional information on asphaltene and oil properties in terms of solubility parameters may be derived from the data obtained. The classical ways of interpreting the results are outlined. Analysis of the effect of oil concentration on FT is shown to add information on the stability of the asphaltenes in the oil. Application to various areas of asphaltene stability related problems is shown. This includes emulsion stability by asphaltenes, change in stability by conversion, oil field deposition, segregation, and asphaltene dispersant evaluation. Recommendations are given on the performance of this type of experiment, such as on titration rates. The analyses of more than 25 different oils are reported in the present work.

Solubility Parameters, Fractional Polarities, and Bond Strengths of Some Intermediary Resins Used in Dentin Bonding

An effective bonding of resin composites to dentin is generally preceded by a conditioning of the surface of the dentin. Previous studies have indicated that the intermediary or adhesive resin should have specific wetting characteristics matching those of the conditioned dentin, in order that optimum bonding can be ensured. The wetting characteristics may be expressed in terms of solubility parameter (delta) and polarity (p) of the resin. The aims of the present study were to determine these variables for a number of compounds used in adhesive resins and to investigate the effects of delta and p on the shear bond strength to dentin. Solubility parameters were obtained according to the method of Small. Fractional polarities were calculated on the basis of measurements of refractive index and dielectric constant of the resins. In the measurements of bond strength, Scotchprep, EDTA + Gluma, or Al2Ox3/glycine were used as dentin conditioners in combination with intermediary resins having various delta and p. For each conditioner, the shear bond strength (BS) could be "explained" by an exponential expression of the form BS = e(a + bx), where x = (delta + cp + d)2, and where a-d are constants depending on the conditioned dentin. It may be concluded that solubility parameter and polarity of the intermediary resins are important variables in the process of bonding to dentin.