PEG Blends Research Articles

Thermal degradation of Polylactide/Poly(ethylene glycol) fibers and composite fibers involving organoclay

In this study, electrospun fibers of melt blended poly(lactic acid) and poly(ethylene glycol), (PLA)-PEG blends involving 10, 15 and 20wt% PEG and their corresponding composites with organically modified montmorillonite, Cloisite 30B were prepared and characterized by x-ray diffraction, differential scanning calorimetry, thermogravimetry and direct pyrolysis mass spectrometry techniques. The narrower fiber diameters observed for the PLA-PEG fibers involving organoclay compared to the corresponding neat fibers were associated with the presence of quaternary ammonium salt as organic modifier increasing electrical conductivity. Strong evidence for phase separation during the electrospinning process was detected for PLA-PEG fibers. On the other hand, for PLA-PEG composite fibers, as a consequence of the diffusion of both PLA and PEG chains from the bulk polymer into the galleries between the silicate layers of the organoclay, the interactions between PLA and PEG chains were enhanced and both components showed similar thermal characteristics, indicating lack of phase separation. These interactions further inhibited the interactions between the PLA chains and organic modifier of the organoclay

Biobased multiblock copolymers: Synthesis, properties and shape memory performance of poly(ethylene 2,5-furandicarboxylate)-b-poly(ethylene glycol)

A series of multiblock copolymers poly(ethylene 2,5-furandicarboxylate)-poly(ethylene glycol) (PEFEGs) were synthesized from available biobased ethylene glycol (EG), 2,5-furandicarboxylic acid (FDCA), and poly(ethylene glycol) (PEG) through a two-step melt polycondensation method. The composition, molecular weight and its distribution, crystallization behavior, thermal stability of PEFEGs were investigated by 1H NMR, GPC, DSC, and TGA, respectively. Effects of composition on crystallization behavior, thermal and mechanical properties of PEFEGs were investigated. Furthermore, shape memory properties of PEFEGs were also investigated systematically. GPC and 1H NMR results show that the products were the multiblock copolymers, not the blend of PEG and PEF. All PEFEGs exhibited the excellent thermal stability. With the increase of PEG chain length and content, melt crystallization peak and melt peak of PEG block became higher and the enthalpy values also became higher. Compared with PEF, the elongation at break of PEFEGs are much better. Meanwhile, PEFEGs exhibit excellent shape memory properties.

Composition‐dependent sol‐gel transition of amphiphilic blend of PEG with hydrophobic gallamide components

ABSTRACTTwo types of poly(ethylene glycol) (PEG)‐based amphiphiles were synthesized: a diblock‐type amphiphile (PEG1) with a hydrophobic moiety on one terminal of PEG (PEG with the molecular weight of 2000), and a triblock‐type amphiphile (PEG2) with hydrophobic moieties on both terminals of PEG. The hydrophobic moiety consisted of hydrophobic C14 alkyl tails covalently linked through a gallamide component. The sol–gel transitions of the aqueous solution of PEG1 and PEG2 were studied. At the PEG amphiphile concentration of 15 wt %, PEG1 gave a clear solution over a wide temperature range from 20 to 80 °C, while PEG2 was partially soluble in water. However, the aqueous blend solution of PEG1 and PEG2 exhibited a hydrogel depending on the blend ratio and temperature. It was considered that the composition of PEG1 and PEG2 governed the sol–gel transition, and that the dynamic moduli could be effectively controlled by changing the mixing ratios of the PEG amphiphiles. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45402.

Poly(ethylene glycol)-based shape-memory polymers

ABSTRACTPoly(ethylene glycol) (PEG) blends photo-curable and thermal activated shape-memory polymers (SMPs), with different activation temperature (Tswitch), have been synthesized and characterized. PEG blends with different molecular weights were chain-end functionalized with isocyanate ethyl methacrylate and photo-cured with UV lamp. Degree of cross-linking of the blend network, determined by gel content measurement, resulted as higher than 95%. The thermal and thermomechanical properties of these SMPs PEG blends were characterized by differential scanning calorimetry and dynamic mechanical analysis. The shape-memory properties of the networks were quantified using thermomechanical three-point bending experiments and showed strain fixity rates higher than 99% and a minimum strain recovery ratio of 82%.

Improved processability and performance of biomedical devices with poly(lactic acid)/poly(ethylene glycol) blends

ABSTRACTTo improve the processability of micropolymer‐based devices used for biomedical applications, poly(lactic acid) (PLA) was melt‐blended with poly(ethylene glycol)s (PEGs) of different molecular weights (MWs; weight‐average MWs = 200, 800, 2000, and 4000; these PEGS are referred to as PEG200, PEG800, PEG2000, and PEG4000, respectively, in this article). The thermal properties, mechanical properties, and rheological properties of the PLA and the PLA–PEG blends were investigated. The tensile samples’ morphologies showed that the low‐MW PEGs filled molds well. The rheological properties confirmed that the low‐MW PEGs decreased the complex viscosity, and improved the processability. With decreasing PEG MW, the PLA glass‐transition temperature decreased. The nanoindenter data show that the addition of PEG decreased the modulus and hardness of PLA. The morphologies of the tensile samples showed that with increasing PEG MW, the thicknesses of the core layers increased gradually. The elongation at break was improved by approximately 247% with the addition of PEG200. Such methods can produce easily processed biological materials for producing biomedical products. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45194.

Metallic Affinity of Toxic and Noble Metals by Particles Produced from Sericin, Alginate and Poly-(Ethylene Glycol)

Biosorbents have been used as a potential alternative to the conventional technologies for removal of toxic metals from water and wastewater. The use of waste material as adsorbent offers significant advantages like low-cost, availability, efficiency, biodegradability, etc. In this study, particles produced from a blend between sericin, alginate and Poly(ethylene glycol) diglycidyl ether (PEG) were used to remove toxic and precious metals from aqueous solutions. Precious metals are found in wastewaters of various industrial processes including metal, ore processing, electronic manufacturing and mining; and the recovery of these metals is profitable to those industrial processes. Sericin is a protein present in cocoon of silkworm (Bombyx mori) usually discharged in the effluent of silk production. Alginate is a natural polysaccharide extracted from abundant sources of brown algae (brown seaweed) properties to this material. The addiction of PEG into a blend of sericin-alginate induces chemical modification that can develop better properties to this material. The objective of this work is to evaluate the metallic affinity and adsorption capacity of particles produced by sericin-alginate blend and sericin-alginate- PEG blend. The blends were dripped in aqueous and alcoholic (ethanol) solutions of CaCl2 and Ca(NO3)2, and then the particles were dried at 100 °C. The simulation of speciation diagrams as functions of pH was performed using Hydra/Medusa software in order to establish the pH to be used in the experiments. The removal of chromium, cadmium, nickel, copper, lead, silver, palladium, platinum and gold ions from aqueous solution by sericin-alginate particles was evaluated through adsorption affinity testes. The results indicated that the presence of PEG improve the adsorption capacity of the biosorbents. For the noble metals the greatest values of reduction and adsorption capacity were obtained to gold (98 – 99 %) and palladium (87 – 89 %), and for the toxic metals it was obtained higher values of reductions to lead (66 – 83 %), cadmium (62 – 79 %), chromium (69 – 74 %) and copper (65 – 74 %).

Visualizing and quantifying the nanoscale hydrophobicity and chemical distribution of surface modified polyethersulfone (PES) membranes.

Chemical modifications bring unique properties into polymeric membranes that may have enhanced filtration or separation efficiencies, antifouling, antimicrobial activity and selectivity. However, there is a lack of nanoscale characterization of the chemical additive distribution and the impacts of chemical modifiers or additives on membrane surface properties, especially those at the nanoscale. In this study, a series of industrially relevant polyethersulfone (PES) membranes modified with poly (ethylene glycol) (PEG) and polyvinylpyrrolidone (PVP) were analysed systematically. Particularly, hydrophobicity and chemical distribution were scrutinized by atomic force microscopy (AFM) and AFM coupled with infrared analysis capability (AFM-IR) for the first time that successfully resolved nanoscale structural and chemical properties of the chemically modified PES membranes. Our results indicated the heterogeneous spatial distribution of PVP and PEG based on their characteristic IR bands and the resulting hydrophobicity distribution on modified membrane surfaces at the nanoscale. Particularly, we established a linear correlation (R2 = 0.9449) between the measured adhesion force and water contact angles, which enabled the examination of local surface hydrophobicity. The PES membranes became more hydrophilic with the increasing blend of PVP and PEG. With AFM-IR, trace amounts (1-4%) of PVP could be identified sensitively on PES membranes based on their unique characteristic IR bands, which were not achieved by FTIR or IR mapping. Overall, these novel characterization approaches hold paramount importance for the design and quality control of polymer membrane modification and manufacturing.

Molecular simulation and experimental studies of the miscibility of polylactic acid/polyethylene glycol blends

Computer simulation and experiments were performed to investigate the miscibility of PLA/PEG blends with different PEG concentrations. Flory-Huggins interaction (χ) parameter used to predict the miscibility for the blends was estimated by molecular dynamic simulation of fully atomistic model. The calculated χ parameter and radial distribution function suggest that the PLA and PEG blends are likely miscible at low PEG concentrations (10–30 wt%), but they become apparently immiscible at higher PEG content (>50 wt%). This result is consistent with density distribution of PLA and PEG beads calculated from dissipative particle dynamics simulation of coarse-grained model. To support the computational results, experiments based on differential scanning calorimetry (DSC) and rheometry were also performed. The DSC thermograms of 90:10, 80:20, and 70:30 (wt/wt) of PLA/PEG blends showed a single glass transition and PLA melting peak, indicating PLA/PEG is miscible over this composition. In rheometry, frequency (ω) dependence of storage moduli (G′) at low frequencies for 75:25 and 70:30 blends indicate that these samples are near the phase separation point.

Miscibility of Starch and Low Molecular Weight Poly (ethyleneglycol) Blends in Aqueous Medium

The miscibility of starch and poly(ethyleneglycol) (PEG)blends in water were investigated by viscosity, densityand refractive index studies. The physical interactionparameters like poly-solvent and blend-solvent have beencalculated using viscosity and density data. Starch/PEGblends were found to be miscible in all studied ratios. Thestudy also revealed that variation of temperature does notaffect the miscibility of starch and PEG blends in theaqueous solution significantly. The miscibility occurs dueto presence of hydroxyl-hydroxyl interactions in theblends. The result obtained reveals that PEG can beeffectively used as gelating agent in starch solution.Keywords: Miscibility, viscosity, polymer interaction, starch, PEG

Effect of PEG addition on pore morphology and biocompatibility of PLLA scaffolds prepared by freeze drying

Purpose A 3wt% poly(L-lactic acid) (PLLA) with different concentrations of polyethylene glycol (PEG, 0~9wt%) was blended and lyophilized to evaluate the morphology and the biocompatibility of the PLLA/PEG scaffolds. The purpose of this study is to investigate the biocompatibility of the PLLA/ PEG blends. Morphology, degradation rate, cytotoxicity, skin sensitization, acute systemic toxicity, and intradermal reactivity are examined.

An investigation into the use of polymer blends to improve the printability of and regulate drug release from pharmaceutical solid dispersions prepared via fused deposition modeling (FDM) 3D printing

FDM 3D printing has been recently attracted increasing research efforts towards the production of personalized solid oral formulations. However, commercially available FDM printers are extremely limited with regards to the materials that can be processed to few types of thermoplastic polymers, which often may not be pharmaceutically approved materials nor ideal for optimizing dosage form performance of poor soluble compounds. This study explored the use of polymer blends as a formulation strategy to overcome this processability issue and to provide adjustable drug release rates from the printed dispersions. Solid dispersions of felodipine, the model drug, were successfully fabricated using FDM 3D printing with polymer blends of PEG, PEO and Tween 80 with either Eudragit E PO or Soluplus. As PVA is one of most widely used polymers in FDM 3D printing, a PVA based solid dispersion was used as a benchmark to compare the polymer blend systems to in terms of processability. The polymer blends exhibited excellent printability and were suitable for processing using a commercially available FDM 3D printer. With 10% drug loading, all characterization data indicated that the model drug was molecularly dispersed in the matrices. During in vitro dissolution testing, it was clear that the disintegration behavior of the formulations significantly influenced the rates of drug release. Eudragit EPO based blend dispersions showed bulk disintegration; whereas the Soluplus based blends showed the ‘peeling’ style disintegration of strip-by-strip. The results indicated that interplay of the miscibility between excipients in the blends, the solubility of the materials in the dissolution media and the degree of fusion between the printed strips during FDM process can be used to manipulate the drug release rate of the dispersions. This brings new insight into the design principles of controlled release formulations using FDM 3D printing.

Topographically and elastically micropatterned PEG-based hydrogels to control cell adhesion and migration

Cell migration is a primary process implicated in several biological processes such as immune response, metastasis or wound healing. Tissue cells respond to, among others, topographic and elastic cues of the extracellular environment. In this work, the migratory behaviour of mouse fibroblasts was investigated on poly(ethylene glycol) hydrogels (PEG) where only one triggering signal was present at a time, i.e. either topographic structures or a stiffness contrast. Despite the intrinsically anti-adhesive properties of PEG polymers, previous experiments in our group have demonstrated that the presence of topographic and mechanical patterns on the surface of those materials do induce fibroblast adhesion. These findings were corroborated in this study. Furthermore, the migration behaviour was investigated. Channel-like structures were prepared by the cast-molding method. We showed that the orientation of the migration tracks with the pattern increased by decreasing the width of the channels; cells migrated randomly inside wide channels, while on narrow ones, they migrated parallel to the direction of the pattern. Besides, biphasic mechanical patterns were created combining polymers with two different degrees of cross-linking with our novel soft-lithographic technique: the Fill-Molding In Capillaries method (FIMIC). In this method, a topographically patterned hydrogel (mold) was filled with the secondary material (filler) via capillary force. This methodology was applied using either pure PEG or a blended material (Blend) of PEG and a block co-polymer containing poly(propylene glycol). Fibroblasts adhered preferentially to the mold lines of the pattern, even on those samples where the mold lines were softer, contradicting the expected durotactic behaviour. Further atomic force microscopy (AFM) analysis of the surface properties of the substrates to explain this phenomenon brought interesting results. The topographic landscape displays convex and concave structures, the former of which being apparently more attractive for the fibroblasts to climb onto and migrate along. On those samples were this topography was detected, the fibroblasts responded to it, while when the sample was practically smooth, they reacted to the elastic pattern. Thus, we demonstrated that the presence of geometric patterns can overrule elastic patterns, helping to elucidate the hierarchy behind the external migratory signals.

Influence of polyethylene glycol (PEG) chain length on the thermal behavior of spin-coated thin films of biodegradable poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)/PEG blends

The influence of the polyethylene glycol (PEG, Mn = 400, 1500, and 3400) chain length on the miscibility and thermal properties of spin-coated films of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHx, HHx = 6.9 mol %)/PEG blends was elucidated by using differential scanning calorimetry (DSC) and temperature-dependent infrared (IR) spectroscopy. To extract more detailed information about the spectral variations induced by the temperature, 2D correlation spectroscopy was applied to the temperature-dependent IR spectra of PHBHx/PEG blends. It was found that PEG 400 was completely miscible with PHBHx while PEG 1500 and 3400 were only partially miscible, reflecting that PHBHx/PEG miscibility decreased with the increasing molecular weight of PEG. The amorphous band of carbonyl group of 70/30 PHBHx/PEG 400 blend is resolved into two bands at 1744 and 1754 cm−1 in the asynchronous spectrum, which is not observed in the corresponding asynchronous 2D correlation spectra of PHBHx and its blend with PEG 1500 and 3400. This observation suggests that we captured the possible existence of two different types of amorphous state in 70/30 PHBHx/PEG 400 blend and the band at 1744 cm−1 is related to the amorphous mixture of PHBHx and PEG 400. Furthermore, 2D correlation analysis and the normalized peak height trends demonstrate that PEG 400 disrupts the crystalline structure of PHBHx, indicating low molecular weight PEG 400 has a clear effect on the thermal properties of PHBHx as well as depressing its melting temperature.

Polymeric nanoparticles for oral delivery of 5-fluorouracil: Formulation optimization, cytotoxicity assay and pre-clinical pharmacokinetics study

Poly(lactic acid) (PLA) or poly(lactic acid)–poly(ethylene glycol) (PLA–PEG) blend nanoparticles were developed loading 5-fluorouracil (5-FU), an antitumor agent broadly used in therapy. A 23 factorial experimental design was conducted to indicate an optimal formulation and demonstrate the influence of the interactions of components on the mean particle size and drug encapsulation efficiency. Optimized PLA nanoparticles presented 294nm and 51% of 5-FU encapsulation efficiency and PLA–PEG blend nanoparticles presented 283nm and 55% of 5-FU encapsulation efficiency. In vitro release assay demonstrated after 320h about 50% of 5-FU was released from PLA and PLA–PEG blend nanoparticles. Release kinetics of 5-FU from nanoparticles followed second order and the release mechanism calculated by Korsmeyer–Peppas model was diffusion and erosion. In the assessment of cytotoxicity over Hep-2 tumor cells, PLA or PLA–PEG blend nanoparticles presented similar IC50 value than free 5-FU. Pharmacokinetic parameters after oral administration of 5-FU were improved by nanoencapsulation. Bioavailability, Cmax, Tmax, t1/2 and distribution volume were significantly improved, while clearance were decreased. PEG presence in nanoparticles didn't influence physicochemical and biological parameters evaluated. PLA and PLA–PEG nanoparticles can be potential carriers for oral delivery of 5-FU.

Three-dimensional analyses of spherulite morphology in poly(oxyethylene) and its blends with amorphous poly(d,l-lactic acid) using X-ray computerized tomography

Three-dimensional structural analyses of huge spherulites of poly(oxyethylene) (PEG) using X-ray computerized tomography (CT) in blends of PEG and amorphous poly(d,l-lactic acid) are reported for the first time. Slit-shaped cracks that were straight or curved were clearly observed using X-ray CT. Furthermore, they appeared to form a set of spokes, presenting a signature of a huge spherulite. Several aspects that are representative of an axialite structure are presented, and they are in good agreement with the intuitively proposed structural model for axialite long ago, although the size scale is much larger in our study.

Experimental investigation of operating conditions for preparation of PVA–PEG blend membranes using supercritical CO2

Poly(vinyl alcohol)–polyethylene glycol, PVA–PEG, blended membrane were prepared using supercritical fluid assisted phase-inversion method, in which scCO2 was used as the anti-solvent. Poly(vinyl alcohol) was utilized as the main polymer, polyethylene glycol as the additive, and dimethyl sulfoxide (DMSO) as the solvent of these polymers. Taguchi method was used to investigate the effect of some operating parameters on the morphology of the membranes. The L16 orthogonal array was selected under the following conditions: pressure (100, 135, 165 and 200bar), temperature (40, 45, 50 and 55°C) and PEG weight percent (0, 0.33, 0.66, and 1%). Total polymer concentration of solutions in all experiment was constant at 10% (w/w). The morphology of the obtained porous membranes was characterized by scanning electron microscopy. Through changing the conditions in each experiment, the average pore diameter changed between 3.75 and 12.2μm. Results from analysis of variance (ANOVA) indicate that PEG concentration was the most significant factor on the average pore size of prepared membranes by 78.7%. This is the first work announcing preparation of PVA–PEG membrane using supercritical CO2.

Thermo-Switchable Pressure-Sensitive Adhesives Based on Poly(N-vinyl caprolactam) Non-Covalently Cross-Linked by Poly(ethylene glycol)

The properties of new hydrophilic pressure-sensitive adhesives (PSA) obtained by blending poly(N-vinyl caprolactam) (PVCL) with short-molecular weight poly(ethylene glycol) (PEG) were studied in aqueous media by a combination of several calorimetric and adhesion testing techniques. We found that the adhesive properties of the blends are the result of an extensive hydrogen bonding network formed between PVCL and PEG similar to the poly(N-vinylpyrrolidone) (PVP)/PEG blends, except the extent of cross-linking is nearly 3 times higher in PVCL–PEG networks. Accordingly, we observed substantially higher peel adhesion in PVCL–PEG blends, which depends strongly on the amount of adsorbed water and the temperature. The adhesive properties of PVCL–PEG gels are considerably diminished when the amount of absorbed water exceeds 30% or at elevated temperature but can be easily recovered by drying or cooling the sample. The observed responsiveness of PVCL–PEG hydrogels in physiologically relevant temperature range makes them interesting candidates for industrial and biomedical applications as smart PSAs.

Three-Dimensional Analyses of Morphology of Polymer Spherulites by X-ray Computerized Tomography

We report 3-dimensional structural analyses of huge spherulites of poly(oxyethylene) (PEG) by the X-ray computerized tomographic (CT) observation in blends of PEG and amorphous poly(lactide). The formation of the huge spherulites is characteristic of PEG and its direct observation by the X-ray CT is reported here for the first time. Slit-shaped cracks were clearly observed by the X-ray CT. Not only the straight cracks but also curved ones were found and it seemed that they overall formed a set of spokes. Furthermore, the scanning electron microscopic observation revealed that the cracks were parallel to bundles of lamellar crystallites. From those observations, we conclude that a set of radial cracks observed under the X-ray CT is a signature of a huge spherulite. Several aspects of an axialite structure are presented and a good agreement with the intuitively proposed structural model is obtained.

Effect of PEG on PLA/PEG blend and its nanocomposites: A study of thermo-mechanical and morphological characterization

In this study, the effect of poly(ethylene glycol) (PEG) on the preparation of Poly(lactic acid) (PLA)/PEG blend and its nanocomposites by melt intercalation method were investigated. The PEG having molecular weight of 6,000 g/mol used with various concentrations (0, 10, 15, 20, 25, 30 wt%) in the preparation of PLA/PEG blend. Again, two types of commercialized organoclay [cloisite 93A (C93A) and cloisite 30B (C30B)] were used for the preparation of blend nanocomposites. With the incorporation of PEG into PLA the tensile strength and modulus decreases, whereas the percentage elongation and impact strength increases predominantly. Further, the PLA/PEG blend nanocomposites showed improved tensile strength and modulus with the addition of oraganoclays into the blend. Scanning electron microscopy (SEM) reveals the surface and miscibility study of the PLA/PEG blend. The effect of clay interaction in the PLA/PEG blend nanocomposites were also studied by using wide angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM). Dynamic mechanical analysis (DMA) was used to investigate the viscoelastic behavior of the blends and its nanocomposites. Differential scanning calorimetry (DSC) study reveals decreased glass transition temperature in case of PLA/PEG blend. The thermal stability of the blend and its nanocomposites were being studied by using thermogravimetric analysis (TGA). POLYM. COMPOS., 35:283–293, 2014. © 2013 Society of Plastics Engineers

Influences of extractant on the hydrophilicity and performances of HDPE/PE‐b‐PEG blend membranes prepared via thermally induced phase separation (TIPS) process

ABSTRACTBlending the block copolymer into the membrane matrix is a convenient and efficient way for membrane modification. In this study, HDPE/PE‐b‐PEG membranes were prepared via TIPS process, and the extractant effect was investigated. An interesting finding was that a non‐polar extractant (n‐hexane) was more conducive to the surface enrichment of PEG chains than a polar solvent (ethanol). The reason was deemed to be the combined effect of entropy drive, interfacial energy, and the swelling behavior. Besides, membrane performances related to the surface chemical properties were studied. Results suggested that the prepared blend membranes extracted by n‐hexane showed enhanced hydrophilicity, anti‐fouling property and water flux. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2680–2687, 2013