Similar Solubility Parameters Research Articles

On the plasticizing properties of divalproex sodium: physicochemical and spectroscopic characterization studies

The objective of the research was to demonstrate the plasticization properties of divalproex sodium, due to its component—valproic acid, on ethyl cellulose, which could prove beneficial for film fabrications or hot melt extrusion based formulations. Films containing 10–50% w/w (DVS/EC) as dry weight were prepared using solvent evaporation method and characterized using texture analyzer, hybrid rheometer, differential scanning calorimetry, thermogravimetry, X-ray diffractometry, polarized microscopy, FTIR, and Raman spectroscopy. It was found that there was a decrease in average peak load, melt viscosity, and glass transition temperature (Tg) while increase in elongation, with increase in concentration of DVS in the films. These results demonstrate the plasticization tendency of DVS on EC, which was attributed to the presence of valproic acid (fatty acid) in DVS. XRD studies showed amorphous nature of the films; however, polarized microscopy revealed the presence of scattered undissolved sodium valproate crystals. The presence of a single Tg established complete miscibility between valproic acid and EC. Films showed reasonable physical stability (similar Tg) at 45 °C/75% RH for 2 weeks (open condition), attributable to the similar solubility parameters of DVS and EC. FTIR and Raman spectroscopy results proved the presence of hydrogen bonding between DVS and EC.

Effects of PBA‐Based Polyurethane Prepolymer as Compatibilizer on the Properties of Polylactic Acid‐Starch Composites

Developing biodegradable materials as alternative to petroleum based materials is highly desirable due to the problem of plastic pollution and shortage of petroleum‐based energy. In this context, the authors have developed bio‐based polylactic acid‐starch (PLA/St) composite materials with Poly‐1,4‐butylene glycol adipate diol (PBA)‐based polyurethane prepolymer (PBAPU) as a compatibilizer. The fourier transform infrared spectroscopy (FT‐IR), scanning electron microscopy (SEM), X‐ray diffraction (XRD), and other test results show that the compatibility between starch and polylactic acid‐starch (PLA) is improved by using the PBAPU compatibilizer. This is due to the polyurethane bond formed as a result of the reaction between the NCO group in polyurethane prepolymer and the OH group in starch. Furthermore, the structures of the soft segments in polyurethane prepolymer and the polylactic acid matrix which belong to the aliphatic polyesters with similar solubility parameters are also very compatible. The results suggested that a novel interface layer is formed between hydrophobic PLA and hydrophilic starch. Consequently, the ensuing PLA/St composite material exhibit increased interfacial compatibility between polylactic acid and starch, with significant improvements in the thermodynamic as well as the mechanical properties. Certainly, this research has significance in the field of bio‐based plastics, resource utilization, and environmental protection.

Diketopyrrolopyrrole‐based polymer fibrils formation by changing molecular conformation during film formation

ABSTRACTThe microstructure of conjugated polymers film is strongly dependent on factors such as the conformation and the film formation processing. In this article, we show how to induce more planarization conformation of conjugated polymer backbone during film formation processing and finally leading to the fibrils formation of the cast film. The conjugated polymer we used is poly[[2,5‐bis(2‐octyldodecyl)‐2,3,5,6‐tetrahydro‐3,6‐dioxopyrrolo[3,4‐c]pyrrole‐1,4‐diyl]‐alt–[[2,2′‐(2,5‐thiophene)bis‐thieno[3,2‐b]thiophen]‐5,5′‐diyl]] (PDPPTT‐T). The main solvent is chloroform (CF), the aliphatic 1,8‐diiodooctane (DIO) is used as the additives, which has similar solubility parameter to the conjugated polymer side chain, is a bad solvent to the conjugated backbone and has a lower volatility than CF. Thus, during the film formation, chloroform was evaporated faster than the additive. After the chloroform evaporated completely, the side chain was still dissolved in the additive, which decreases the steric hindrance and improves planarization conformation of the conjugated backbone of PDPPTT‐T. Films processed using the aliphatic additives have fibrillar morphology while films cast from the CF solvent were featureless. TEM images reveal that the fibrils were about 30 nm in width and several hundred nanometers in length. The backbones of PDPPTT‐T were parallel to the long axis of fibrils. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 1079–1086

Extended release delivery system of metoprolol succinate using hot-melt extrusion: effect of release modifier on methacrylic acid copolymer.

The current study reports on the manufacturing of extended release dosage forms of metoprolol succinate via hot-melt extrusion (HME) technology. Either Eudragit®S100 and Eudragit®L100 alone or in combination with release modifying agent Polyox™ WSR 303 and Eudragit®L100-55 were processed to obtain complete and faster release. Metoprolol succinate with similar solubility parameters to polymer was dispersed in polymer matrix and was characterized by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Stability of drug after extrusion was confirmed by thermogravimetric analysis and high-performance liquid chromatography. Physical characterization method exhibited that the drug was homogeneously dispersed in non-crystalline state in Eudragit®L100-55-based formulations whereas in semi-crystalline state in Polyox™ WSR 303. The drug release percentage was below 3 and 40% in 0.1N HCL with Eudragit®L100-55- and Polyox™ WSR 303-containing formulations, respectively, and exhibited pH-dependent dissolution properties. The drug-release mechanism was anomalous with Polyox™ WSR 303 formulations whereas diffusion through pore formation was obtained with Eudragit®L100-55. Both Eudragit®L100-55 and Polyox™ WSR 303 changed the release mechanism and kinetics of drug release from thermally processed dosage forms. The optimized stable formulation is similar to the marketed formulation with F2 value of 72.36. Thus, it can be concluded that HME was exploited as an effective process for the preparation of controlled release matrix system based on pH-dependent polymer matrices Eudragit®S100 and Eudragit®L100.

Prediction of compatibility of organomodified clay with various polymers using rheological measurements

Two natrified montmorillonites of different origin and three organomodified fillers (including two non-commercial experimentally prepared) were investigated either in dispersions in various solvents or in mixtures with three polymeric matrices. Rheological measurements of filler dispersions in solvents were used as a tool for determination of the affinity of modified filler's surfaces towards substrates with various polarities. These data were used for the prediction of filler structure in polymer matrices. The measurements in various liquids provide a fast and rather simple tool to determine the suitability of particular filler for certain polymer. This approach is based on the Hildebrand solubility parameter (δ) where materials with similar values of δ are likely to be miscible. The same or similar solubility parameters of chosen solvents and polymers are taken as tool for selecting appropriate pairs polymer – solvent considering the compatibility with particular filler. The predictions made according to rheological data were confirmed with rheology of real nanocomposites of the respective fillers in three polymeric matrices, namely low density polyethylene, polyamide 12 and polycaprolactone and supported by comparison with results obtained by transmission electron microscopy (TEM) as commonly used method for characterization of polymer - clay nanocomposites.

Application of MOSCED To Predict Limiting Activity Coefficients, Hydration Free Energies, Henry’s Constants, Octanol/Water Partition Coefficients, and Isobaric Azeotropic Vapor–Liquid Equilibrium

Modified Separation of Cohesive Energy Density (MOSCED) is a solubility parameter-based method to predict limiting activity coefficients. In addition to making quantitative predictions, MOSCED may additionally be used to understand the underlying molecular-level driving forces for intuitive solvent selection and formulation. A major improvement of MOSCED over similar solubility parameter methods is that it splits the association term. We show by example how this change allows MOSCED to better model the molecular interactions of associating fluids. While parametrized to predict limiting activity coefficients, we demonstrate the ability to predict hydration-free energies, Henry’s constants in water, and octanol/water partition coefficients. We focus on water as MOSCED was previously found to perform substantially worse when water was the solvent. Comparison is made to molecular simulation and mod-UNIFAC, and we find for the studied reference set that predictions with MOSCED were in better agreement with exp...

Environmental effects in biaxially orientated Polymethyl Methacrylate

Environmental stress cracking (ESC) is commonly found in polymers when submerged in an environment under applied stress. In such conditions, a crack may initiate and propagate from a material defect until it reaches a critical size and causes catastrophic failure. It is known that materials with a denser molecular structure are less prone to ESC, hence amorphous polymers often suffer greatly from this effect. A fracture mechanics approach was employed to investigate the fracture mechanism and crack growth in both air and environment. Two different grades of PMMA (amorphous and biaxially stretched PMMA) were tested in solvents with similar solubility parameters as this is known to hasten crazing. Time for crack initiation and crack speed were obtained and plotted against their corresponding fracture toughness. Thus, the ESC resistance of each material can be compared and component life expectance can also be predicted. To validate the experimental results, scanning electron microscopy (SEM) was used to examine the fracture mechanism of ESC.

Effects of compositions on the stability of polyols-in-oil-in-water (P/O/W) multiple emulsions

ABSTRACTPolyols-in-oil-in-water (P/O/W) multiple emulsions were successfully prepared by using polyols as inner aqueous phase to avoid instabilities caused by water. The influence of polyols, oils and emulsifiers on the morphology and stability of P/O/W multiple emulsions were studied and the stability mechanisms of this new kind of multiple emulsions were also explored. Glycerol that has the worst solubility in oil phase contributed to the formation of stable inner droplets which agree with the Ostwald Ripening theory. Mineral oil worked well with the system proving that oils possessing similar solubility parameters with the hydrophobic group of emulsifiers benefited for system stability. Several typical surfactants had been investigated in this article, and it turned out that emulsifiers Cetyl PEG/PPG-10/1 Dimethicone and the block copolymer Poloxamer 407 were suitable for the P/O/W system. The stability of the system affected by different compositions was evaluated based on microscopic observation and rheological measurements. The novel multiple emulsions will provide enlightening recommendations for future investigations and applications in cosmetic, food and pharmaceuticals, including drug delivery and the encapsulation of hydrophilic actives and actives that are soluble in polyols.

Effect of crosslinking agents on the dispersive behaviour of polymer particles in seed swelling polymerisation

Abstract This study focused on the effect of crosslinker structure between PMMA on the dispersity of crosslinked particles in seed swelling polymerisation. We used five different crosslinking agents in an assessment of the dispersity of crosslinking monodisperse particles using PMMA seed particles in seed swelling polymerisation. These results show that the structure of the crosslinking agent affects the dispersity during the swelling stage. According to the solubility parameter theory of computation, the departure of similar solubility parameter causes the swollen particles to segregate into more dispersity.

Comparative behavior of in situ silica generation in saturated rubbers: EPDM and hydrogenated natural rubber

ABSTRACTRole of carbon‐carbon double (CC) bonds content and their position in ethylene‐propylene diene ter‐polymer (EPDM), hydrogenated natural rubber (HNR) and natural rubber (NR) on in situ silica formation using tetraethoxysilane (TEOS) as a silica precursor is comparatively investigated. Glass transition temperature (Tg) reflecting rubber chain flexibility is found as an important factor for in situ silica generation via swelling method. Despite of similar solubility parameters, NR has higher TEOS‐swelling degree resulting in the higher in situ silica content (30.8 phr) than EPDM (3.50 phr) and HNR (10.4–17.6 phr) due to the higher Tg of EPDM and HNR providing the less chain flexibility to be swollen in TEOS solution. The morphological analysis implies that CC bonds in saturated rubbers may be agglomeration sites for in situ silica particles. For practical applications, saturated rubbers containing in situ silica/NR vulcanizates showed the improvement of mechanical properties and resistance of thermal and ozone degradation. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44748.

Theoretical insight into the temperature-dependent acetonitrile (ACN) solvent effect on the diacetone diperoxide (DADP)/1,3,5-tribromo-2,4,6-trinitrobenzene (TBTNB) cocrystallization

A temperature-dependent diacetone diperoxide (DADP)/1,3,5-tribromo-2,4,6-trinitrobenzene (TBTNB)-acetonitrile (ACN) interfacial model was constructed to study the solvent effect on cocrystal formation. The DADP/TBTNB cocrystal morphology was predicted by Growth Morphology Model. The interfacial models were built and simulated by molecular dynamics (MD) method at temperatures ranging from 298 to 358K with 10K intervals. The surface electrostatic potentials of DADP/TBTNB cocrystal framework and ACN molecule were calculated at B3LYP/6-311++G (d, p) level of density functional theory. Properties of the interfacial model (i.e. surface areas and polarities) have been recognized to be significant factors that influence the preparation of the cocrystal. The results of the properties and energy analyses indicate that ACN molecules adsorbed on (11−1) cocrystal surface are stronger than those on (200), (110), and (020) surfaces; DADP molecules are more inclined to interact with TBTNB in (200) and (110) interfacial models. Combining with the similar solubility parameter values of DADP and TBTNB in ACN solvent, the solvent effects on the DADP/TBTNB cocrystallization could not only inhibit growth of the cocrystal in a special face but promote the interaction strength between coformers. The influence becomes more significant as the increasing of properties (such as S, polarities). In addition, the theoretical study shows that the best condition of forming DADP/TBTNB cocrystal in ACN solvent is near 338K.

Discussing of influence mechanism of Chinese herbal monomer on physical stability of cream

This study left flavonoids and alkaloids Chinese herbal monomer with common parent nucleus as cream base carriages drug respectively, cream base were prepared with stable span 60-tween 80 emulsification system. The near-infrared stability analysis technology was performed to quantitatively characterize the physical stability of cream. Base on the theory of gel network structure, theory of emulsification, theory of solubility parameter and theory of double layer, the influence mechanism of Chinese herbal monomer on physical stability of cream was discussed. The results showed that tetrahydropalmatine, matrine and naringenin had similar solubility parameter value with cream base material, creams prepared with those Chinese herbal monomer have higher Zeta potential value and stronger physical stability, and that those creams had similar microstructure information with cream base. However, a larger solubility parameter difference exists between baicalin, baicalein, berberine, palmatine and cream base material. Creams prepared with those Chinese herbal monomers had lower Zeta potential value and poorer physical stability, and that those creams had great different microstructure information with cream base.

Separation properties of aluminium–plastic laminates in post-consumer Tetra Pak with mixed organic solvent

The separation properties of the aluminium-plastic laminates in postconsumer Tetra Pak structure were studied in this present work. The organic solvent blend of benzene-ethyl alcohol-water was used as the separation reagent. Then triangle coordinate figure analysis was taken to optimize the volume proportion of various components in the separating agent and separation process. And the separation temperature of aluminium-plastic laminates was determined by the separation time, efficiency, and total mass loss of products. The results show that cost-efficient separations perform best with low usage of solvents at certain temperatures, for certain times, and within a certain range of volume proportions of the three components in the solvent agent. It is also found that similar solubility parameters of solvents and polyethylene adhesives (range 26.06-34.85) are a key factor for the separation of the aluminium-plastic laminates. Such multisolvent processes based on the combined-system concept will be vital to applications in the recycling industry.

Extraction and percolation of PAEs from chemical protective gloves

Phthalates (PAEs) have high solubility in polymers and are added as plasticisers to increase the flexibility and plasticity of polymeric materials. In this study, methanol, hexane, ethyl ether and acetone were used for the extraction of PAEs from chemical protective gloves at temperatures of 20–80 °C. DEHP (di-2-ethylhexyl phthalate) and DBP (di-n-butyl phthalate) were extracted from neoprene, nitrile and PVC glove samples using the above four solvents. The extraction level of DEHP from the glove samples was proportional to the Log Kow values of the extraction solvents. This result implied that PAEs were more soluble in non-polar solvents and were likely to be extracted from the gloves. Increasing the extraction temperature resulted in a higher extraction of DBP and DEHP from the gloves. In the ASTM F739 permeation method, the aromatic solvents permeated through the glove samples and dissolved DEHP. If the permeant and DEHP had similar solubility parameters, DEHP was likely to be leached from the gloves. The modelling results indicated that the permeation behaviour of the organic solvent in the PVC glove was non-Fickian diffusion. It was speculated that the plasticiser increased the diffusion coefficients of the permeants in the PVC gloves. This study suggested that the potential dissolution and leaching of PAEs from chemical protective gloves should be a concern for workers who handle organic solvents.

The Effect of Solvatochromism on the Interfacial Morphology of P3HT-CdS Nanowire Nanohybrids

Increasing performance in organic/inorganic bulk heterojunctions hybrid photovoltaic systems hinges not only on the structure of the inorganic component but also on the morphology of the polymeric component. Changing the morphology of the organic component is a facile way of changing the morphology of the interface between the inorganic and organic components in the bulk heterojunction system. Engineering this interface to more efficiently split photogenerated excitons and transport these carriers to electrodes can increase the efficiency of photovoltaic devices. In this report, we investigate the effect of solvent quality on the morphology of the poly(3-hexylthiophene)-2,5-diyl (P3HT) polymer-semiconductor interface (solvatochromism). We have found that creating more order within the P3HT main chain in solution and prior to deposition has a profound effect on the nature of the P3HT-CdS nanowire interface. Solvents with a larger difference in solubility parameter, Δδ, relative to P3HT, such as methanol and isopropanol, create larger rod domains in the P3HT main chain and result in larger domains of crystalline P3HT at the interface. Solvents with similar solubility parameters as P3HT, such as pyridine and hexanol, create relatively shorter rod domains in the main chain and, as a result, nanohybrids with reduced crystallinity. The results of this paper further cement the importance of manipulating the rod-coil transition in the conducting polymers such as P3HT to improve the crystallinity at the polymer-semiconductor interface that can easily be scaled up to improve the efficiency of bulk heterojunction photovoltatic systems.

Significantly improving the thermal stability and dispersion morphology of polyhedral oligomeric silsesquioxane/polysiloxane composites by in-situ grafting reaction

In this work, two different polyhedral oligomeric silsesquioxanes (POSS)—octaisobutyl-POSS (OIBS) and allylisobutyl-POSS (AIBS)—were incorporated into poly(methylvinylsiloxane) (VMQ) by melt mixing and then the corresponding blends were chemically crosslinked by peroxide. NMR analysis revealed that AIBS molecules containing double bonds were successfully grafted onto VMQ macromolecular chains during the crosslinking of VMQ. Morphology and thermal stability studies by various methods discovered that the in-situ formation of chemical linking between POSS molecules and VMQ chains could significantly improve the dispersion of POSS particles and the thermal stability of VMQ. For the VMQ with 5 wt% POSS, AIBS exhibited nano-dispersion in VMQ matrix and improved the thermal stability of VMQ, but inert OIBS molecules aggregated extensively to form crystals and adversely affected the thermal stability, although AIBS and OIBS have similar solubility parameters and thermal stabilities. Further studies on the thermal stability of VMQ with different contents of AIBS showed that the thermal stability first increased with increasing content of AIBS but then began to decrease as the content of AIBS exceeded 7.5 wt%. X-ray diffraction and extraction experiments showed that extensive ungrafted AIBS molecules and their aggregates started to appear in the VMQ matrix as the content of AIBS exceeded 7.5 wt%. The study revealed that the grafted POSS hindered the thermal degradation of silicone rubber to cyclic oligomers but the ungrafted POSS favored the thermal degradation.

Solvent-vapor induced self-assembly of a conjugated polymer: A correlation between solvent nature and transistor performance

A systematical investigation on solvent-vapor annealing in polymer thin film transistors is performed using a thiazolothiazole-bithiazole conjugated polymer as the active layer. Film morphology, packing order and device performance are closely related to polarity and solubility parameter of the annealing solvent and annealing time. The formation of highly ordered and closely connected fibrillar domains is realized by using a solvent with similar solubility parameter and polarity to the conjugated polymer. Field-effect transistors based on pristine polymer films exhibit a highest charge carrier mobility of 0.0067cm2V−1s−1. After solvent vapor annealing with THF for 48h, the mobility boosts up to 0.075cm2V−1s−1. This correlation between solvent polarity, solubility parameter and film morphology, packing order and mobility provides a useful guideline towards high performance polymer thin film transistors with solvent-vapor annealing method.

Novel Solution to Oil Spill Recovery: Using Thermodegradable Polyolefin Oil Superabsorbent Polymer (Oil–SAP)

This paper discusses a novel approach that may provide a complete solution to combating oil spills. The technology is centered on a cross-linked polyolefin terpolymer (x–OS–DVB), containing 1-octene, styrene, and divinylbenzene units, which is an oil superabsorbent polymer (oil–SAP) with aliphatic and aromatic side chains that have similar solubility parameters (oleophilic and hydrophobic properties), with the hydrocarbons in crude oil. Some x–OS–DVB terpolymers, with desirable morphology (amorphous, low Tg, and high free volume) and lightly cross-linked (complete network) structure, show rapid oil absorption and swelling to reach a capacity 45 times their weight. The capacity of oil uptake (swelling) is inversely proportional to the cross-linking density. The combination of selective oil absorption (without water) and tough mechanical strength offers buoyancy, stability, and easy recovery on water surfaces. The recovered oil-swelled gel, containing more than 98% oil and 2% x–OS–DVB, is suitable for regular oil-refining processes (an economic, no waste, and no pollutant approach). The bulk side chains in x–OS–DVB result in a relatively low ceiling temperature for depolymerization and zero heating residue at 450 °C, well below the first distillation step (>600 °C) in oil refining. Furthermore, polyolefins are the most inexpensive polymeric material, with a large production capability around the world. Overall, this cost-effective new polyolefin oil–SAP technology shall dramatically reduce the environmental impacts from oil spills and help recover one of our most precious natural resources.

Effect of the Alcohol Cosolvent in the Removal of Caffeine by Activated Carbons

The effect of the addition of methanol and 2-propanol as cosolvents on the caffeine adsorption onto activated carbons was evaluated by both kinetic and equilibrium studies. The kinetic results presented a good adjustment to the pseudo-second-order kinetic model and reveal that the alcohol cosolvent has a double negative effect on caffeine adsorption: it enhances caffeine’s solubility lowering its affinity toward the adsorbent and it seems to compete with caffeine for the adsorption active sites. The change in the isotherm shape from L to F type, when the mixture 2-propanol/water was used, was justified in terms of the higher interaction between the caffeine and 2-propanol molecules. This solvent presents the most similar Hansen three-dimensional solubility parameters when compared to the ones of caffeine. The overall adsorption results point out that when the sample with acidic surface chemistry is used, the water adsorption is favored and consequently the effect of the cosolvent is less marked and is mai...

Effect of porogenic solvent on the porous properties of polymer monoliths

AbstractPolymer monoliths with open pores and median pore size of about 15 nm–3 μm have been successfully synthesized by photoinitiated polymerization of butyl methacrylate and ethylene glycol dimethacrylate monomers. The solubility of the monomers in a porogenic solvent is determined by Hildebrand solubility parameter, and it is found that it has great effect on the pore size of the polymers synthesized. Polymers with larger pores are usually generated with poorer solvents for the monomers. However, polymers with different pore sizes and porosities have been obtained using porogenic solvents with similar Hildebrand solubility parameters. The evaporation rate of the porogenic solvents might be another critical factor affecting the properties of the polymer monoliths. Moreover, the effect of water as a cosolvent on the pore size and porosity of the polymers have also been investigated. Polymers with larger pore size have been prepared with the presence of water due to the occurrence of earlier phase separation in the polymerization. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013