Polymer Blends Of Poly Research Articles

Simultaneous Slowdown of Segmental and Terminal Relaxation of Both Components in Dynamically Asymmetric Poly(ε-caprolactone)/Poly(styrene-co-acrylonitrile) Blends

The molecular relaxation of the dynamically asymmetric miscible polymer blend poly(styrene-co-acrylonitrile) (SAN)/poly(e-caprolactone) (PCL) was investigated by differential scanning calorimetry, broadband dielectric spectroscopy, and rheological measurements. The relaxation times and the broadness of relaxation spectrum at both segmental scale and chain scale increase when the temperature decreases. The relaxation times at two length scales are linearly correlated, and the broadness of the terminal relaxation is wider than that of the segmental relaxation. Moreover, it is found that both the segmental relaxation time and the terminal relaxation time increase with the content of the counterpart at the same temperature distance from the effective glass transition temperature. It implies that segmental relaxation time at the effective glass transition temperature is composition-dependent due to the specific interactions between PCL and SAN. By combining the time-dependent diffusion double reptation (TDD-DR...

Poly(vinyl alcohol)/Chitosan composites: Physically transient materials for sustainable and transient bioelectronics

Abstract The development of sustainable and transient materials is not only significant importance for environmental concern and human health, but also meets the highly demand for specific application in biomedical, military and intelligence fields. In this study, polymer blends of poly(vinyl alcohol) and chitosan were used to prepare sustainable and degradable polymer films which are promising to be applied as substrates for transient bioelectronics. The effect of the material composition and chemical structures on the mechanical, thermo-physical and thermal stability was studied and characterized by tensile testing, dynamic mechanical analysis, thermogravimetric analysis, and Fourier-transform infrared spectroscopy, respectively. In addition, the transiency rate of the composites as a function of temperature and composition was investigated and discussed. It is found that the transience rate of the composites can be tailored by controlling the composition and chemical structures. Addition of chitosan tends to decrease the time constant. In addition, the temperature also strongly affects the transience behavior of the polymer blends. The tailored performance and programmable degradation of these novel polymer composites provide a sustainable platform for widely application in transient biomedical and electronic devices.

Synthesis of powdered and granular N -(3-trimethoxysilylpropyl)diethylenetriamine-grafted mesoporous silica SBA-15 for Cr(VI) removal from industrial wastewater

Abstract In this study, both powdered and granular N-(3-trimethoxysilylpropyl)diethylenetriamine (DAEAPTS)-grafted mesoporous silica SBA-15 were synthesized for hexavalent chromium (Cr(VI)) removal from industrial wastewater. The powdered adsorbents were synthesized via grafting DAEAPTS onto SBA-15. The Cr(VI) sorption characteristics of the adsorbents were examined under batch conditions in synthetic Cr(VI) solutions. Batch experiments revealed that the Cr(VI) sorption was favorable at acidic pH conditions with the greatest sorption at pH 3. The Cr(VI) sorption was a fast process, reaching equilibrium within 10 min. The maximum Cr(VI) sorption capacity was 330.88 mg/g. To overcome limitations of the powdered adsorbents for large-scale application (hydraulic and separation problems), the spherical granular adsorbents (average size = 1.13 ± 0.09 mm) were prepared through immobilizing the powdered DAEAPTS-grafted SBA-15 into a polymer blend (poly(vinyl alcohol) and sodium alginate). The granular adsorbents were applied for Cr(VI) removal from two industrial plating wastewaters in flow-through column experiments. In the experiment with wastewater 1 (Cr(VI) concentration = 328.7 mg/L), the Cr(VI) sorption capacity of the granular adsorbents was 158.8 mg/g. In the experiment with wastewater 2 (Cr(VI) concentration = 2671.6 mg/L), the pristine and regenerated adsorbents were tested to demonstrate that the granular adsorbents could be successfully regenerated and reused for Cr(VI) removal.

Nanocomposite Membranes Comprising Crosslinked Polymer Blends of Poly(vinyl alcohol)/Poly(styrene sulfonic acid-co-maleic acid) and Fumed Silica Nanoparticles.

Nanocomposite polymer electrolyte membranes comprising a crosslinked polymer blend of poly(vinyl alcohol)/poly(styrene sulfonic acid-co-maleic acid) (PVA/PSSA-co-MA) and fumed silica nanoparticles were prepared for direct methanol fuel cell (DMFC) applications. Silica nanoparticles could be incorporated well uniformly in the completely miscible system, which can form a three-dimensional network structure to achieve the enhancement of mechanical properties as well as the additional reduction of methanol permeability. The optimized proton conductivities and methanol permeability of the PVA/PSSA-co-MA membrane with silica nanoparticles of 10 wt.% were 0.0482 S cm-1 at room temperature and 5.78 × 10-7 cm2 s-1 at the methanol concentration of 40% (w/w), respectively.

Preparation and property testing of polymer blends of poly(lactic acid) and poly(butylene succinate) plasticised with long-chain fatty acids

ABSTRACTThis study investigates the influence of three fatty acids (lauric acid, palmitic acid, and stearic acid) on biodegradable polymer blends based on poly(lactic acid) (PLA) and poly(butylene succinate) (PBS), containing different weight ratios (100:0, 100:2, and 100:4) of fatty acids on the transparency, mechanical properties, morphology, contact angle, and water vapour permeability. All of the blends were pressed into thin films and tested. The experimental results showed that the properties of the samples varied with chain length and amounts of the fatty acids. Thus, it could be concluded that use of fatty acids opens up new ways for the plasticisation of PLA/PBS blends for use as new bioplastics.

Efficiency enhancement of ternary blend organic photovoltaic cells with molecular glasses as guest acceptors

Abstract Previously reported glass-forming perylenediimide (PDI-glass) and diketopyrrolopyrrole (DPP-glass) acceptors were used as ternary components to modulate the morphology and electron transport properties of bulk heterojunctions composed of the polymer blend poly(3-hexythiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM). Both ternary acceptors show strong absorption in the visible range and energy levels intermediate between that of P3HT and PCBM. In the blends, both amorphous materials occupy the interface between P3HT and PCBM domains without significantly altering film morphology. The incorporation of 20% PDI-glass and 15% DPP-glass in ternary blend devices has resulted in conversion efficiency enhancements of 38% and 36%, respectively. Additionally, the incident photon to electron conversion efficiency of the ternary devices of these materials was increased with additional photocurrent between 660 and 750 nm, indicating that these materials efficiently contribute to light harvesting. This justifies the efficiency enhancements via the charge transfer mechanism. Furthermore, these ternary devices show high stability towards both moisture and oxygen.

Mitigating thermal runaway of lithium‐ion battery by using thermally sensitive polymer blend as cathode binder

ABSTRACTThermally sensitive binder (TSB) is developed as an internal safety mechanism of lithium‐ion battery (LIB). The TSB is a polymer blend of poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP). Compared with regular PVDF binder, the softening and swelling of TSB are more pronounced when temperature is above 110 °C. With the TSB, the cycling performance of LIB cell is not affected; upon nail penetration, the heat generation rate is significantly reduced. The crystallinity of TSB is an important factor. This technology may lead to the development of thermal‐runaway‐mitigating LIB cells. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45737.

Poly(Lactic Acid)-Polybutylene Succinate-Activated Carbon Composite Foams

Polymer blends of poly (lactic acid) (PLA) and polybutylene succinate (PBS) containing activated carbon (AC) were foamed by using Azodicarbonamide (ADC) through an extrusion process. The composite foams containing 5 phr of AC had lower density than those without AC loading for PLA:PBS ratios of 90:10, 80:20, 70:30, and 60:40. The incident of higher void fraction was the consequences of more foaming nucleation centers which were induced by adding AC in the composite foam. Maximum reduction of density by 50% with the void fraction of 50% was achieved when both ADC and AC were applied at 5 phr with the PLA:PBS ratio of 80:20. The addition of AC in composite foams enhanced the crystallization in PBS phase but had no effects on PLA crystallinity. The thermal stability of composite foams with and without AC dosages for each PLA:PBS proportion was slightly changed. For PLA-PBS blend foams, the more PLA loading there was the more tensile strength and modulus there would be. For PLA-PBS-AC composite foams, AC could improve the modulus and tensile strength of composite foams in PBS-rich samples whereas no effect on PLA-rich samples.

Disparity in hydrophobic to hydrophilic nature of polymer blend modified by K 2 Ti 6 O 13 as a function of air plasma treatment

Abstract Polymer blends of Poly (vinylidenefluoride) (PVDF)/Poly (methyl methacrylate) (PMMA) were modified by Potassium hexa-titanate oxide (K 2 Ti 6 O 13 ) in weight fraction ratio. The blends were further exposed to air plasma treatment. The alteration of surface morphology due to plasma treatment was analyzed using polarizing optical, scanning electron and atomic force microscopic techniques. The confirmation of chemical composition and elemental analysis of untreated and treated blends were done using Fourier transform infrared spectrum (FTIR) and energy dispersion spectroscopy (EDS). Theoretical methods of calculating contact angle (θ°), surface energy (γ SE ), and roughness average (R a ) were disclosed to evaluate the experimental data. The microscopic observations clearly demonstrated the synergic effect induced by plasma treatment which improved the surface energy and formation of micro texture. Surface energy was estimated from contact angle data, which demonstrate the significant disparity in hydrophobic to hydrophilic nature. It is well known that the air plasma treatment incorporates polar functional groups onto the surface, which is responsible for the decrease in contact angle. Further, the increase in surface roughness as seen from AFM is also responsible for the decrease in contact angle and hydrophilic nature. The optimization of barrier properties of polymer blends using plasma treatment can be useful in the development of liquid attracting layer applications.

Polymer blends of poly(2-cyanoethyl vinyl ether) and poly(methyl methacrylate) with improved dielectric properties for flexible electronics

Polymer blends of poly(2-cyanoethyl vinyl ether) and poly(methyl methacrylate) with improved dielectric properties for flexible electronics

Imidazolium-based ionic liquid type dependence of the bending response of polymer actuators

Actuators based on polymer blends of poly(vinylidene fluoride) (PVDF) with 40% of different ionic liquids (IL) are prepared by solvent casting. [C2mim][Cl], [C6mim][Cl], [C10mim][Cl], [C2mim][NTf2], [C6mim][NTf2] and [C10mim][NTf2] were selected in order to evaluate the effect of anion and cation sizes in the bending properties. The microstructure, mechanical and electrical properties of the blend depend on the IL type, which in turn leads to a different bending response. In particular, the mechanical properties are independent on the IL type but the AC conductivity of the composites depend more on the anion type than on the size of the alkyl chain connected to the imidazolium based cation. Thus, the bending response of the IL/PVDF composites is correlated with the anion and cation sizes and a maximum bending response of 0.3% is achieved for a 10V square signal in the IL/PVDF composite with 40wt% content of [C2mim][NTf2].

In vitro evaluation of poly (lactic-co-glycolic acid)/polyisoprene fibers for soft tissue engineering.

The polymeric blend of poly (lactic-co-glycolic acid) (PLGA) and polyisoprene (PI) has recently been explored for application as stents for tracheal stenosis and spring for the treatment of craniosynostosis. From the positive results presented in other biomedical applications comes the possibility of investigating the application of this material as scaffold for tissue engineering (TE), acquiring a deeper knowledge about the polymeric blend by exploring a new processing technique while attending to the most fundamental demands of TE scaffolds. PLGA/PI was processed into randomly oriented microfibers through the dripping technique and submitted to physical-chemical and in vitro characterization. The production process of fibers did not show an effect over the polymer's chemical composition, despite the fact that PLGA and PI were observed to be immiscible. Mechanical assays reinforce the suitability of these scaffolds for soft tissue applications. Skeletal muscle cells demonstrated increases in metabolic activity and proliferation to the same levels of the control group. Human dermal fibroblasts didn't show the same behaviour, but presented cell growth with the same development profile as presented in the control group. It is plausible to believe that PLGA/PI fibrous three-dimensional scaffolds are suitable for applications in soft tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2581-2591, 2017.

Effect of Compatibilizer on PLA/PP Blend for Injection Molding

Polymer blends of poly(lactic acid) and polypropylene were prepared for the application to injection molding products. Due to the phase separation of PLA and PP, the addition of polypropylene-graft-maleic anhydride (PP-g-MAH) as a compatibilizer was studied. The polymer blends were comprised of PLA:PP ratios 80:20 and 20:80 with addition of 1, 3 and 5 wt% of PP-g-MAH. The product samples were processed dry blend with injection molding process and the products were subjected to thermal, mechanical properties and morphology analysis. The thermal analysis confirmed that addition of PP-g-MAH has no effect on crystalline melting temperature of the polymer components as well as no effect on the mechanical properties. The morphology study of the polymer blends confirmed the adhesion of PLA and PP by assistance of PP-g-MAH. The addition of more amount of PP-g-MAH resulted in high polarity of a compatibilizer and decreased the compatibility with PLA. The tensile strength of polymer blends increased with increasing amounts of PLA. The research results confirmed the application of polymer blend system to injection molding process.

The colour stability of natural dye coating films consisting of chlorophyll after exposed to UV-A

Purpose This paper aims to study the colour stability of chlorophyll and the effect of copper (II) nitrate – Cu(NO3)2 – as an additive in natural dye coating films after being exposed to ultraviolet-A (UV-A). Design/methodology/approach The natural dye was extracted from the leaves of Cassia alata L. using absolute ethanol as the solvent. The extract was divided into two parts and, one of it was added with 3 wt.% Cu(NO3)2 as an additive. The polymer blend of poly(methyl methacrylate) (PMMA) and acrylic polyol was used as the coating binder. Both parts of the dye with and without additive were mixed with the blended polymer in a specific ratio. The resulted mixtures were applied as coating films on glass substrates. The colour stability of the coating films on exposure to UV-A with the time of exposure was observed with Commission internationale de l’éclairage (CIE) L*a*b* colour coordinates. The hidden power by the means of reflectivity and glossiness of the coatings was also studied. Statistical standard deviation (STD) was used to analyse the data. Findings The test showed that the coating films containing Cu(NO3)2 had smaller colour differences, (ΔE*) indicating higher colour stability. The analysis on hidden power also showed that the coating film with Cu(NO3)2 was 1.6 times more stable than the film without additive. All the measurements in this study were observed within 35 days of duration. Research limitations/implications This paper implies the potential of using natural dye extracted from Cassia alata L. leaves as a stable dye colourant for coating applications. Practical implications The coating film developed in this study is suitable for glass substrate applications. Originality/value A new method of preparing solvent-based coating film from PMMA–acrylic polyol with chlorophyll colourant is introduced in this study.

Effect of environmental factors on Poly(3‐hydroxybutyrate‐co−3‐hydroxyvalerate)/Poly(butylene adipate‐co‐terephthalate)/montmorillonite nanocomposites with antimicrobial agents

Short‐running of mineral oil, the increasing waste problem and the raising consciousness of our society are increasing biopolymer's potential for becoming an important alternative for petroleum based plastics. However, applications of biopolymers are still limited, which is partly caused by insufficient properties and high prices of some biopolymers. This study focuses on a polymer blend of poly(3‐hydroxybutyrate‐co−3‐hydroxyvalerate) and poly(butylene adipate‐co‐terephthalate) which is reinforced with organomodified montmorillonite. Moreover, two natural propolis additives and an industrial antimicrobial are added to the materials with the objective to convey them antimicrobial properties. The effect of environmental factors such as water absorption, aging by weathering test, and antimicrobial attack on the thermal behavior and colorimetry of the biopolymer nanocomposites is investigated. These results contribute to the understanding of the structure‐property relationship of biocomposite materials for various applications, e.g. in packaging. POLYM. COMPOS., 39:915–923, 2018. © 2016 Society of Plastics Engineers

Fluorine-Enriched Melt-Blown Fibers from Polymer Blends of Poly(butylene terephthalate) and a Fluorinated Multiblock Copolyester.

Melt-blown fibers (dav ∼1 μm) were produced from blends of poly(butylene terephthalate) (PBT) and a partially fluorinated random multiblock copolyester (PFCE) leading to enhanced hydrophobicity and even superhydrophobicity (static water contact angle = 157 ± 3°) of the associated fiber mats. XPS measurements demonstrated quantitatively that the surface fluorine content increased systematically with the bulk loading of PFCE, rising to nearly 20 atom %, which corresponds to 41 wt % PFCE at a bulk loading of 10 wt %. The PBT/PFCE fibers exhibit greater fluorine surface segregation than either melt-blown PBT/poly(ethylene-co-chlorotrifluoroethylene) (PBT/PECTFE) fibers or electrospun fibers obtained from blends of poly(styrene) and fluoroalkyl end-capped polystyrene (PS/PSCF). Dynamic contact angle measurements further demonstrated decreased surface adhesion energy of the melt-blown PBT/PFCE fiber mats due to the blooming of PFCE to the surface.

Rheological Analysis of Polymer Interactions and Ageing of Poly(Methylvinylether-Co-Maleic Anhydride)/Poly(Vinyl Alcohol) Binary Networks and Their Effects on Mucoadhesion

Polymer blends of poly(vinylalcohol, PVA) and poly(methylvinylether-co-maleic anhydride, PMVE/MA) were formulated and their viscoelastic and mucoadhesive properties characterised. The viscoelastic and mucoadhesive properties were dependent on polymer concentration, molecular weight of PVA and PVA:PMVE/MA ratio. Alteration of these properties allowed platforms to be designed to offer defined rheological and mucoadhesive properties, properties that could not be achieved using monopolymeric platforms. A strong correlation was noted between the modulus of the polymeric blends and mucoadhesion. After storage, the polymeric blends underwent rheological structuring (ageing) with an attendant enhancement of mucoadhesion. In certain blends containing the highest molecular weight of PVA (146-186 kDa), storage ultimately resulted in an increase and then a significant decrease in the rheological and mucoadhesive properties, the latter phenomenon being accredited to polymer recrystallisation. Ageing of the rheological and mucoadhesive properties was modelled using an exponential growth model, allowing predictions of the storage period associated with the maxima in viscoelastic and mucoadhesive properties. These observations highlight the possible implications whenever interactive polymeric blends are employed in drug delivery. Caution is therefore urged whenever a formulation strategy based on interactive polymer blends is employed to ensure that ageing is fully understood and mathematically characterised.

Dependence of Melt Viscosity of Polymer Nanocomposites on Type of Carbon Nanotubes Fractal Structures

Keywords: nanocomposite, blend, carbon nanotubes, melt, viscosity, fractal. As it is known, any real fractal object can be simulated as a bulk or surface fractal. In the first case the structure fractality is extended to the entire volume of the object and in the second one – to its surface. For nanocomposites, the matrix of which makes up polymer blend poly(ethylene terephthalate)/poly(butylene terephthalate), the fractal dimensions of both structure and surface of ring-like formations of nanofiller (multiwalled CNT) were calculated. It has been found out that in case of their notion as bulk fractals, i.e. matrix polymer penetration in ring-like formations internal regions, the strong enhancement of the nanocomposites melt viscosity is observed and in case of surface fractals this parameter is independent on nanofiller contents.

Complexion Formation in PVA/PEO/CuCl<sub>2</sub> Solid Polymer Electrolyte

Solid polymer electrolyte films based on polymer blends of poly(vinyl alcohol) (PVA) and poly(ethylene oxide) (PEO), with different concentration of copper (II) chloride (CuCl2) were prepared using casting technique. Optical studies were performed using Fourier transform infrared (FT-IR) and Ultraviolet-visible (UV-Vis) spectroscopy. The optical properties of these films were varied by varying CuCl2 concentration. The results show the absorption edge for electrolyte samples shifts toward a lower energy region by increasing the salt concentration, leading to the band gap reduction. The band gap energy data showed that the incorporation of CuCl2 into the polymeric system causes charge transfer complexes in the blend polymer, which lead to increase in the electrical conductivity, by providing additional charges in the lattice. The PVA/PEO/CuCl2 solid polymer electrolyte films exhibit good UV shielding properties in the wavelength range from 190 to 400 nm.

Submicronic etched features of silicon with high aspect ratio obtained by cryogenic plasma deep-etching through perforated polymer thin films

ABSTRACTWe report the preparation of nanomasks for silicon plasma etching, which is not based on full top-down approaches such as conventional lithographic process. We used laterally phase separated polymers thin films (30 to 100 nm thick) obtained from immiscible polymer blends of poly(styrene) PS and poly(lactide) PLA, PS being the major component, spin-coated onto silicon substrates. Despite the high incompatibility of the two polymers, submicronic domains were obtained in the film. The selective extraction of the minor component (PLA) led to the formation of a perforated layer of PS at the top of the silicon substrate, and was used as a mask for the selective etching of the silicon. For that purpose, we used a cryogenic etching process where the silicon substrate was cooled at a cryogenic temperature (∼ -120°C) and exposed to a monocyclic SF6/O2 plasma. It was possible to etch anisotropic profiles with vertical sidewalls and minimal defects. Etched feature with an aspect ratio of 7 were obtained in these conditions. We determined that the selectivity of etching (Si/PS) was 11:1, with a silicon etching rate of 0.8 µm/min. The selectivity of these masks was further increased when using the inorganic replicas of the polymer template (50:1) or with chemical modifications of the PS by RuO4 (80:1), allowing for increased aspect ratio etched features (up to 20 in the latter case). Optimized etching processes (such as STiGer process) were also used in order to improve the reproducibility and robustness of the method.