Polymer Blend Technique Research Articles

Preparation and Characterization of Polycarbonate-Based Blend System with Favorable Mechanical Properties and 3D Printing Performance.

Recently, material extrusion (MEX) 3D printing technology has attracted extensive attention. However, some high-performance thermoplastic polymer resins, such as polycarbonate (PC), cannot be processed by conventional MEX printing equipment due to poor processing performance. In order to develop new PC-based printing materials suitable for MEX, PC/poly(butylene adipate-co-terephthalate) (PBAT) blends were prepared using a simple polymer blending technique. It was found that the addition of PBAT component significantly improved processing performance of the PC, making the blends processable at 250 °C. More importantly, the PC was completely compatible with the PBAT, and the PBAT effectively reduced the Tg of the blends, endowing the blends with essential 3D printing performance. Furthermore, methyl methacrylate-butadiene-styrene terpolymer (MBS) was introduced into the PC/PBAT blends to improve toughness. SEM observations demonstrated that MBS particles, as stress concentration points, triggered shear yielding of polymer matrix and absorbed impact energy substantially. In addition, the MBS had little effect on the 3D printing performance of the blends. Thus, a PC/PBAT/MBS blend system with favorable comprehensive mechanical properties and 3D printing performance was achieved. This work can provide guidance for the development of novel MEX printing materials and is of great significance for expanding the variety of MEX printing materials.

Mechanical and thermal degradation behavior of inorganic fullerene-liked tungsten disulfide reinforced perfluoroalkoxy/poly(ether-ether-ketone) nanocomposites

Enhancing the mechanical, thermal properties and obtaining the thermal degradation mechanism of polymers is crucial for designing advanced polymer composites. Here, an inorganic fullerene-like tungsten disulfide nanoparticle reinforced perfluoroalkoxy and poly(ether-ether-ketone) (PFA/PEEK/IF-WS2) nanocomposites were developed using solution mixing and polymer blending techniques. This work investigated the mechanical, thermal properties and thermal degradation behavior of PFA/PEEK blends and PFA/PEEK/IF-WS2 nanocomposites. FTIR analysis demonstrated the interacting hydrogen bonds. SEM and TEM showed the compatibility of the incompatible PFA/PEEK blend was improved with the introduction of IF-WS2. TG analysis indicated that IF-WS2 enhanced the thermal stability of PFA/PEEK blends. The PFA/PEEK/IF-WS2 nanocomposites exhibited better mechanical properties, especially tensile properties, with a 37.9% increase in tensile strength and a 106% increase in storage modulus. DSC showed that compared with pure PFA, the initial melting temperature of the 80/20/1% sample was increased by 8.64 ℃, and the crystallinity was increased by 9.44%. TG-IR analysis showed that IF-WS2 delayed the time of thermal decomposition products and reduced the yield of organic volatiles. Excellent barrier properties and good compatibility of IF-WS2 in the PFA/PEEK blends are considered to be the keys to enhance mechanical and thermal performances.

Insulating Polymer Blend Organic Thin-Film Transistors Based on Bilayer-Type Alkylated Benzothieno[3,2-b]naphtho[2,3-b]thiophene.

Herein, we developed a practical method to produce high-performance organic thin-film transistors (OTFTs) based on highly layered crystalline organic semiconductors (OSCs) that form bilayer-type layered herringbone (b-LHB) packing and exhibit high intrinsic mobility. We applied the insulating polymer blend technique using a typical b-LHB OSC of 2-octyl-benzothieno[3,2-b]naphtho[2,3-b]thiophene (2-C8-BTNT) and fabricated polycrystalline thin-film transistors (TFTs) via short-duration spin coating and subsequent annealing. The use of blends and the choice of polymer additive strongly affected the performance of the polycrystalline TFTs, and poly(methyl methacrylate) (PMMA) blend TFTs exhibited a high mobility exceeding 4 cm2/(V s) and small device-to-device variations. Using extended techniques in atomic force microscopy (AFM), we investigated the thin-film morphologies by bimodal AFM and the carrier transport properties by Kelvin probe force microscopy (KPFM). We demonstrated that the PMMA blend system enables the formation of a well-ordered polycrystalline thin film induced by vertical phase separation between the OSC and PMMA over a large area, resulting in uniform TFT performance. These findings pave the way for obtaining high-performance TFTs using simple processes, representing a substantial advancement toward the realization of printed electronics.

Characterisation of electrospun PS/PU polymer blend fibre mat for oil sorption

Electrospun polystyrene (PS) fibre mat has been shown to have great potential as an oil sorbent due to its high sorption capacity and oil-water selectivity. Poor mechanical properties, due to the lack of inter-fibre bonding, has been a limiting factor in its use in such applications. In this study, mats of polymer-blends of polystyrene (PS) and thermoplastic polyurethane (PU) fibres, in different polymer weight ratios, were produced and investigated for possible oil sorption application.A comprehensive physico-chemical, thermal, mechanical and sorption characterisation of the different polymer-blends was undertaken, to examine the effect of blend ratio on the fibre mat. Characterisation was by field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, differential scanning calorimetry (DSC), thermo-gravimetric and differential analysis (TG-DTA), mechanical tensile testing, and by sorption analysis.The microstructural properties of the fibres appeared significantly dependent upon the relative blend ratio. DSC revealed that good interaction/miscibility existed between the two polymers. Tensile strength characterisation showed that a pure PS fibre mat had a poor tensile strength, but the value increased over one order of magnitude with the addition of PU in the polymer matrix, attributed to the formation of inter-fibre bonds. Conversely, the sorption capacity (SC) decreased with increasing PU addition. Modulating the blend ratio could therefore provide a balance between the desired sorption capacity and the mechanical behaviour of resultant mats.Sorption capacity is a complex interaction between fibre and mat characteristics but the polymer blend technique reported here offers a simple, effective and inexpensive method of addressing the poor mechanical properties of electrospun PS fibre by adding PU and via enhancing micro/nano scale interactions between the two polymers in the blend.

Ionically Crosslinked Complex Gels Loaded with Oleic Acid-Containing Vesicles for Transdermal Drug Delivery.

Skin is an attractive site for drug administration partly because of its easy accessibility and favorable properties (e.g., less invasiveness and high patient compliance) over some other common routes of administration. Despite this, the efficiency in transdermal drug delivery has been largely limited by poor skin permeation. To address this problem, this study reports the generation of oleic acid-containing vesicles, which can enhance the drug delivery efficiency while showing good stability and limited skin disruption. Upon being loaded into a complex gel, along with the incorporation of the polymer blending technique, a delivery system exhibiting tunable transdermal flux of 2,3,5,4′-tetrahydroxystilbene 2-O-β-D-glucoside is reported. Taking the good biocompatibility and tunable delivery performance into account, our system warrants further development and optimization for future applications in the treatment of skin diseases.

A review and future prospect of polymer blend mixed matrix membrane for CO2 separation

In recent years, carbon capture technology has received much attention to limit the adverse effect caused by rising carbon dioxide (CO2) concentration in the atmosphere. Membrane technology has risen as an attractive option for carbon capture as it is less energy–intensive and more environmentally friendly compared with adsorption, absorption, and cryogenic separation. Polymeric membranes dominate the gas separation industries as they are cheaper and easier to fabricate compared with inorganic membranes but are bound to the permeance-selectivity trade-off limitation. Recently, researchers have been modifying polymeric membrane by polymer blending and mixed matrix membranes (MMMs) to overcome the limitation. Polymer blending yields a polymer blend that combines the benefits of two or more polymeric material. Polyethylene glycol (PEG) and polyethersulfone (PES) are common polymeric materials used in the gas separation industry for membrane fabrication. PEG and PES were reviewed in this paper as potential polymer blends that efficiently separate CO2 due to their chemical characteristics. Another technique to overcome the trade-off limitation is fabricating MMMs that incorporate both polymeric membrane material and inorganic filler. However, MMM fabrication presents challenges such as polymer-filler incompatibility, void formation, and filler agglomeration due to unsuitable filler. Functionalized multi-walled carbon nanotubes (MWCNTs-F) were reviewed as fillers that are able to overcome the dispersion and polymer-compatibility issues and increase the gas separation performance of membranes. Hence, MMM that is fabricated from PEG, PES, and MWCNTs-F that combines both polymer blending and MMM techniques is believed to be a breakthrough for CO2/N2 separation.

Preparation and Composition Optimization of PEO:MC Polymer Blend Films to Enhance Electrical Conductivity.

The polymer blend technique was used to improve amorphous phases of a semicrystalline polymer. A series of solid polymer blend films based on polyethylene oxide (PEO) and methylcellulose (MC) were prepared using the solution cast technique. X-ray diffraction (XRD), Polarized optical microscope (POM), Fourier transform infrared (FTIR) and electrical impedance spectroscopy (EIS) were used to characterize the prepared blend films. The XRD and POM studies indicated that all polymer blend films are semicrystalline in nature, and the lowest degree of crystallinity was obtained for PEO:MC polymer blend film with a weight ratio of 60:40. The FTIR spectroscopy was used to identify the chemical structure of samples and examine the interactions between chains of the two polymers. The interaction between PEO and MC is evidenced from the shift of infrared absorption bands. The DC conductivity of the films at different temperatures revealed that the highest conductivity 6.55 × 10−9 S/cm at ambient temperature was achieved for the blend sample with the lowest degree of crystallinity and reach to 26.67 × 10−6 S/cm at 373 K. The conductivity relaxation process and the charge transport through the hopping mechanism have been explained by electric modulus analysis. The imaginary part of electrical modulus M″ shows an asymmetrical peak, suggesting a temperature-dependent non-Debye relaxation for the PEO:MC polymer blend system.

Improving thermal stability and mechanical performance of polypropylene/polyurethane blend prepared by radiation-based techniques

Polymer blending techniques can address the disadvantages of polyolefin-based polymers by creating a mixture of polymers with different characteristics. One of the polyolefin-based polymers is polypropylene (PP), which has good mechanical strength and machinability, but its weakness is impact resistance at low-temperature. In contrast, polyurethane (PU) has excellent mechanical and thermal properties. However, blending PP and PU has been limited because PP is a hydrophobic polymer, and PU is a hydrophilic polymer. In this study, we used gamma-irradiation (doses of 25 and 50kGy) to graft styrene onto PU to change its hydrophilicity into hydrophobicity, and we developed PP blends with styrene grafted PU (PP/SPU) blends. With increasing styrene content and radiation dose, the surface morphologies (determined by using a field emission scanning electron microscope (FE-SEM) were smoother than PP blended unmodified PU owing to the styrene that was successfully grafted onto the PU and blended with PP. The mechanical properties of the PP/SPU blends were confirmed using a universal testing machine (UTM). Whereas the elongation at break of the PP was 518%, the low-temperature resistance (−20°C) of the PP was decreased to 304%. However, the elongation at the break of the PP/SPU blends was almost unchanged in terms of both the mechanical property (594%) and low-temperature resistance (607%). After holding in oven at 150°C for 1 h, the thermal stability of PP/SPU increased by more than quadrupled, compared to PP. In addition, the permittivity of PP/SPU increased with radiation dose compared to PP. Energy dispersive X-ray spectroscopy (EDS), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and differential scanning calorimetry (DSC) were also used to evaluate the blended polymers. Therefore, this study confirmed the possibility of developing highly functional polymers using radiation-based techniques.

Microwave absorbing properties of Biocompatible polymer blend films

Using polymer blending technique, the biocompatible polymers Polyvinylchloride (PVC) and Polyvinylpyrrolidone (PVP) were mixed with conducting polymer Polypyrrole (PPy) to fabricate conductive blend films of PVC-PVP-PPy for their probable application in electromagnetic shielding of microwave diagnostic and therapeutic devices. Complex permittivity, microwave absorbing properties and electromagnetic shielding effectiveness of these films have been investigated in Ku band (12.4 GHz-18 GHz) using vector network analyzer. Various parameters such as loss tangent, ac conductivity, absorption coefficient and skin depth have been evaluated. Electromagnetic shielding effectiveness of around -17dB is obtained when the content of PVP-PPy in films is high It is observed that absorption acts as a dominant shielding mechanism in blend film with high content of PVP-PPy.

Reactive blends based on polyhydroxyalkanoates: Preparation and biomedical application

Polyhydroxyalkanoates (PHAs) are a class of natural polyesters as carbon and energy reserves by >300 species of microorganisms. They are fully biodegradable, biocompatible and piezoelectric biopolymers that have attracted much attention recently as the biomaterial of choice for medical applications. However, the toughness, processability and hydrophilicity of PHAs need to tune to expand their applications as tissue engineering scaffolds or drug delivery systems. Reactive polymer blending is one of the most economic and versatile way to produce materials combining the desired properties via forming the compatibilizing agents in situ or inducing the chemico-physical interactions between polymer blends. This review focuses on the PHAs-based reactive blends aiming to present a brief introduction to the mechanism of reactive polymer blending technique, including the formation of H-bonding, branching/crosslinking copolymers, graft copolymers or complex copolymers during polymer blending process.

Preparation of Carbon Monoliths by a Simple Polymer Blend Technique

Porous carbon monoliths are prepared by carbonization of a simple polymer blend, in which phenolic resin (PF) as carbon precursor, polyvinyl butyral as pore former and activated carbon as conducting additive and contraction inhibitor are used to make polymer blend. The results show that the carbon monoliths, with a narrow pore size distribution with mean controlled diameters in the sub-micron/micron range, can be easily produced by controlling the stabilization temperature of the PF, the carbonization temperature, and particle diameters of the precursor powders. The pore size decrease as the stabilization temperature of the PF increases or the particle diameters of the precursor powders decreases. The electrical resistance of the carbon monoliths decreases as the carbonization temperature increases, but the average pore diameter and volume of the carbon monoliths are almost constant as the carbonization temperature increases.

Toughening of Poly(Lactic Acid) by Blending with Poly(Ethylene-co-Octene)

Poly (lactic acid) or PLA is one of the most promising biodegradable and bio-based materials commercially available for the manufacturing of environmentally friendly plastic products. Although, PLA has high modulus and biodegradable property, its brittleness and low thermal stability are the disadvantages. Several means have been explored so as to overcome this drawback, i.e. copolymerization, addition of some additives as well as blending with other polymers. The polymer blending technique has attracted the most attention because of its simplicity and economical reason. It was reported that the addition of a polyolefin elastomer e.g. poly (ethylene-co-octene) or POE in PLA matrix can effectively improve its brittleness. The aim of this study is thus to investigate the effect of the amount of POE on mechanical properties of the polymer blends. POE was also modified with glycidyl methacrylate in order to improve the compatibility between the two polymers. The results pointed out that the impact strength of PLA markedly increased while tensile and flexural properties of the blends were slightly lower than that of neat PLA. It was also observed that the tensile and flexural properties were slightly higher when the modified POE was used rather than those with unmodified POE which indicated the improved interfacial compatibility between two polymers.

Gas transport properties of hyperbranched polyimide/hydroxy polyimide blend membranes

Gas transport properties of novel hyperbranched polyimide/hydroxy polyimide blends and their silica hybrid membranes were investigated. Gas permeability coefficients of the blend membranes showed positive deviation from a semilogarithmic additive rule. The enhanced gas permeability were resulted from the increase in free volume elements caused by the intermolecular interaction between terminal amine groups of the hyperbranched polyimide and hydroxyl groups of the hydroxy polyimide backbone. Additionally, CO2/CH4 separation ability of the blend membranes was markedly promoted by hybridization with silica. The remarkable CO2/CH4 separation behavior was considered to be due to characteristic distribution and interconnectivity of free volume elements created by the incorporation of silica. For the hyperbranched polyimide/hydroxy polyimide blend system, polymer blending and hybridization techniques synergistically provided the excellent CO2/CH4 separation ability.

Hydrogen storage in CO 2-activated amorphous nanofibers and their monoliths

Amorphous carbon nanofibers (CNFs), produced by the polymer blend technique, are activated by CO 2 (ACNFs). Monoliths are synthesized from the precursor and from some ACNFs. Morphology and textural properties of these materials are studied. When compared with other activating agents (steam and alkaline hydroxides), CO 2 activation renders suitable yields and, contrarily to most other precursors, turns out to be advantageous for developing and controlling their narrow microporosity (<0.7 nm), V DR(CO 2). The obtained ACNFs have a high compressibility and, consequently, a high packing density under mechanical pressure which can also be maintained upon monolith synthesis. H 2 adsorption is measured at two different conditions (77 K/0.11 MPa, and 298 K/20 MPa) and compared with other activated carbons. Under both conditions, H 2 uptake depends on the narrow microporosity of the prepared ACNFs. Interestingly, at room temperature these ACNFs perform better than other activated carbons, despite their lower porosity developments. At 298 K they reach a H 2 adsorption capacity as high as 1.3 wt.%, and a remarkable value of 1 wt.% in its mechanically resistant monolith form.

Development of microporous activated carbon using a polymer blend technique and its behavior towards methylene blue adsorption

Coloured wastewater is released as a direct result of the production of dyes as well as from various other chemical industries. Many dyes and their breakdown products may be toxic for living organisms. Activated carbon is one of the best materials for removal of dyes from aqueous solutions. The present study describes the adsorption behaviour of methylene blue dye on three microporous activated carbons, where two samples (AC-1 and AC-2) were pre- pared by a polymer blend technique and the other is a microporous activated carbon (ARY-3) sample from viscose rayon yarn prepared by chemical-physical activation. The effects of contact time and activated carbon dosage on decolourisation capacity have been studied. The results show that activated carbon having mixed microporosity and mesoporosity show tremendous decolourisation capacity for methylene blue. In addition, the activated carbon in the powder form prepared by the polymer blend technique shows better decolourisation capacity for methylene blue than the activated rayon yarn sample.

Activation of polymer blend carbon nanofibres by alkaline hydroxides and their hydrogen storage performances

In the present work we study the hydroxide activation (NaOH and KOH) of phenol-formaldehyde resin derived CNFs prepared by a polymer blend technique to prepare highly porous activated carbon nanofibres (ACNFs). Morphology and textural characteristics of these ACNFs were studied and their hydrogen storage capacities at 77 K (at 0.1 MPa and at high pressures up to 4 MPa) were assessed, and compared, with reported capacities of other porous carbon materials. Phenol-formaldehyde resin derived carbon fibres were successfully activated with these two alkaline hydroxides rendering highly microporous ACNFs with reasonable good activation process yields up to 47 wt.% compared to 7 wt.% yields from steam activation for similar surface areas of 1500 m 2/g or higher. These nano-sized activated carbons present interesting H 2 storage capacities at 77 K which are comparable, or even higher, to other high quality microporous carbon materials. This observation is due, in part, to their nano-sized diameters allowing to enhance their packing densities to 0.71 g/cm 3 and hence their resulting hydrogen storage capacities.

Growth of silicon carbide nanorods from the hybrid of lignin and polysiloxane using sol-gel process and polymer blend technique

We report here the formation of silicon carbide (SiC) nanorods from organic–inorganic hybrid of the commercially available lignin and sol-gel derived nanosized silica. The SiC nanorods were identified by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The surface morphology shows the formation of continuous nanorods of diameter in the range of 50–200 nm. The X-ray diffraction (XRD) pattern show peaks at 2 θ = 35.5° and 60.2° indicate the formation of β-SiC and a sharp peak at 2 θ = 22.1° suggests the presence of unreacted crystalline silica (crystoballite). The characteristic vibration of SiC at 791 cm − 1 in Fourier transform infrared spectroscopy (FTIR) was also observed.

Electron microscope studies on the disintegration of core/shell polymer structure during heat treatment in carbon nanotube preparation by a polymer blend technique

The polymer blend technique has been revealed to give a poor yield in the preparation of carbon nanotubes (CNTs) by spinning three-layered core/shell polymer particles having different thermal decomposition properties. In order to elucidate the reason for the low yields obtained by this method, we carried out the present study on employing three-layered core/shell particles, (core) PMMA / PAN-PMAA / PMMA (shell), with electron microscopic techniques. The core/shell structure was not disintegrated by the stabilization and carbonization processes. The influences of the copolymer composition of the carbon precursor polymer (CPP), PAN-PMAA, on the deformation of the core/shell structures were studied. When the concentration of PMAA in the PAN-PMAA copolymer is 3 mol%, the core/shell structure was retained, but when the concentration of PMAA was increased to 7.5 mol%, the core/shell structure disintegrated. By using a copolymer with 4 mol% PMAA, a hollow cigar-like nanostructured carbon was formed; this can be considered to be an indication for the formation of a CNT. Thus, the copolymer composition was found to be an important parameter for the preparation of CNTs by the polymer blend technique. The results obtained in this study indicated the possibility of obtaining CNTs by properly tuning the copolymer composition of the CPP.

Electron microscopic studies on disintegration of core/shell polymer structure during heat treatment process in carbon nanotube preparation by polymer blend technique

Electron microscopic studies on disintegration of core/shell polymer structure during heat treatment process in carbon nanotube preparation by polymer blend technique

Preparation method of carbon nanofibers from phenolic resin using a polymer blend technique

Preparation method of carbon nanofibers from phenolic resin using a polymer blend technique