Miscible Blends Research Articles

Spatial Variations in Hydrogen Bonding Interaction within Polymer Blends Revealed by Infrared Nanoimaging.

Hydrogen bonding plays a crucial role in enhancing the miscibility of polymer blends, allowing for the tailoring of their physicochemical properties to meet diverse application demands. However, nanoscale imaging of its impact on the phase-separation behavior of multicomponent polymeric materials remains largely unexplored. In this work, we introduce scattering-type scanning near-field optical microscopy (s-SNOM) equipped with a broadly tunable quantum cascade laser as a tool for investigating spatial variations in hydrogen-bonding interactions within blends of polyvinyl acetate (PVAc) and polyvinylphenol (PVPh), spin-coated from tetrahydrofuran solution. Our multiwavelength s-SNOM imaging approach reveals distinct features, namely, the hydrogen bonding mediated miscible PVAc/PVPh blend and the phase-separated PVAc domain. These results provide a more detailed understanding, indicating that hydrogen bonding may not lead to a completely uniform blend throughout the film, as previously believed, based on far-field spectroscopy. Furthermore, through comparisons between topography and near-field images, we find that the PVAc/PVPh hydrogen-bonded domain exhibits a strong affinity for the Si surface with its native oxide, while the free (non-hydrogen-bonded) PVAc film is vertically phase-separated atop the blend. Overall, our work demonstrates that s-SNOM is an effective and efficient tool for studying intermolecular interactions relevant to various chemical and biological phenomena.

Repurposing trityl-substituted triphenylamine-based polyimides for gas separation membranes by blending with a fluorinated polyimide

In the attempt to develop gas separation membranes by reusing polymers with no film-forming ability but with great potential for this purpose, blending has been approached as a simple, time- and cost-effective strategy. Herein, blends of trityl-substituted triphenylamine (TTA)-based polyimides and a fluorinated polyimide (6F-PI) were involved to prepare dense membranes by drop-casting technique. The two blend components involved in variable amounts led to different film morphologies with a strong impact on most blends' properties and gas separation performance. According to optical microscopy, SEM, AFM, and FTIR investigations, the blend series containing hexafluoroisopropylidene (6F) groups in both polyimide components proved to be fully miscible at the molecular levels. When a single 6F-based component was integrated into the blend, the polymers proved to be compatible, but only partially miscible, with a two-phase structure, in which 6F-PI wrapped around the TTA-PI growth fibrillar domains. However, all blends displayed a single glass transition and FTIR bands which do not sum the ones of the polymer components, as well as a high thermal stability, close to that of 6F-PI. Regardless their miscibility level, all blends behaved as classical polyimide films, with good mechanical properties and chemical resistance to corrosive media like acid vapors or basic solutions. The blend composition and diimide structure of TTA-PI little affected the dielectric behavior, unlike the gas separation performance that strongly depended on these characteristics. The higher amount of 6F groups in the miscible blends endowed the membranes with superior permeability and selectivity, allowing in some cases to surpass the trade-off rule. Generally, the gas permeability decreased with the increase of TTA-PI content, with some exceptions. The low intermolecular interfacial interactions promoted by TTA-PI were found to be beneficial to preserve a good selectivity of gas molecules with a small kinetic diameter (He, CO2) though their permeability is lost. The gas permeability changes as a function of the blend composition and structure were mostly due to changes in the solubility coefficient and less from gas diffusion capability, at least for CO2 and N2.

Revealing enhanced dilution effect of conjugated polymers in partially miscible blends

AbstractRecent experiments have shown that hole traps could be suppressed in polymer light‐emitting diodes under current stress by diluting the light‐emitting conjugated polymers within an “inert” large‐bandgap host material. However, it is unclear why there is an enhanced dilution effect in partially miscible blends rather than fully miscible blends, as intuition would suggest that better miscibility leads to better dilution. In this work, we propose a cascade analysis by combining multiple fluorescence microscopic techniques and all‐atom molecular dynamics simulations to study the solid‐to‐solid dilution of poly[2‐methoxy‐5‐(2‐ethylhexyloxy)‐1,4‐phenylenevinylene] (MEH‐PPV) in MEH‐PPV/polystyrene (PS) blends and MEH‐PPV/poly(vinylcarbazole) (PVK) blends. By varying the molecular weights of PS and PVK, we can regulate their miscibility with MEH‐PPV. The results corroborate that the dilution effect is enhanced in partially miscible blends rather than fully miscible ones. This is because, in partially miscible blends undergoing phase separation, the concentration of MEH‐PPV is notably decreased in the phase occupying the majority of the volume, leading to an overall greater dilution effect than in fully miscible blends. Moreover, MEH‐PPV could adopt the more extended conformation in the fully miscible blend, causing a shorter intermolecular distance to further undermine the dilution effect. These findings explain the seemingly counterintuitive more effective dilution effect observed in the recently reported partially miscible blends and provide guidance for further enhancing the performance of future generations of polymer light‐emitting diodes.

Change in Concentration of Amorphous Region Due to Crystallization in PTT/PET Miscible Blends.

In a miscible crystalline/crystalline blend of poly(trimethylene terephthalate) (PTT) and poly(ethylene terephthalate) (PET), the PET spherulites grew at 240 °C when the PTT content was 30 wt% or less. The growth rate of PET spherulites decreased with time due to the exclusion of PTT from the growth front of PET spherulites into the amorphous region, resulting in a three-stage crystallization process. Due to the exclusion, the spherulite growth stopped before the volume filling of the PET spherulites, causing the formation of an excluded PTT amorphous region. When the temperature was lowered from 240 °C to 210 °C, the PTT spherulites grew in the excluded PTT amorphous region. The spherulite growth rate of PTT in the excluded PTT amorphous region was equivalent to that of a blend of 60-70 wt% PTT in 30/70 PTT/PET. These results suggest a significant change in the PTT concentration in the amorphous region, from the initial PTT content of 30 wt% to 60-70 wt%, due to the exclusion of PTT during the melt crystallization of PET at 240 °C.

Thermoplastic Starch Processed under Various Manufacturing Conditions: Thermal and Electrical Properties.

Eco-friendly materials like carbohydrate-based polymers are important for a sustainable future. Starch is particularly promising because of its biodegradability and abundance but its processing to thermoplastic starch requires optimization. Here we developed thermoplastic maize starch materials based on three manufacturing protocols, namely: (1) starch/glycerol manual mixing and extrusion, (2) starch/glycerol manual mixing, extrusion, and kneading, (3) starch/glycerol/water manual mixing and kneading. The physical properties were investigated by differential scanning calorimetry, thermogravimetric analysis, and broadband dielectric spectroscopy. As expected from a partially miscible blend, the dielectric spectra revealed two distinct α-relaxations for the glycerol-rich and the starch-rich phases, respectively. By employing kneading after extrusion, the miscibility between the two phases was found to improve based on thermal and dielectric methods. Moreover, the addition of water during the premixing stage was observed to facilitate phase separation between starch and glycerol, with the α-relaxation dynamics of the latter being comparable to pure glycerol.

Crystalline and Amorphous Interface Simulations of Donor-Acceptor Blends.

In an organic solar cell, exciton dissociation and charge transport to generate current depend on interface and bulk morphology, respectively, and their rates dictate device performance. Blend miscibility and processing determine the final morphology. We investigate the blend miscibility of P3HT and O-IDTBR, employing our recently developed "push-pull" computational technique, and explore its effect on nanoscale morphology. The resulting Flory-Huggins χ parameter is primarily enthalpic, and the blend exhibits UCST behavior. To directly simulate an equilibrated morphology in such a blend requires large (30 nm) systems and long (10 μs) simulations, which we attain with our virtual site coarse graining technique. In the resulting amorphous phase-separated state, O-IDTBR swells P3HT by about 15%, but does not percolate within the P3HT-rich phase. The interfacial profile depends on crystallinity: the amorphous interface is several nanometers wide, whereas an acceptor crystal induces order in the adjacent donor polymer, forming a sharp interface quite similar to a crystal-crystal interface. The wide amorphous interface promotes more donor-acceptor contacts with a wide range of relative orientations; however, the acceptors do not form a percolating network, which will likely lead to charge recombination. A crystal interface exhibits fewer donor-acceptor contacts with primarily face-on orientation that are more likely to charge-separate because of instant access to the preferred domain.

Miscible blends of chemically‐modified poly(phenylene oxides) with styrene copolymers containing polar groups

AbstractPoly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) is well‐known to be miscible with polystyrene, but immiscible with styrene copolymers containing polar groups. Certain nitrated‐PPOs (NPPOs) were found to be miscible with copolymers of styrene/acrylonitrile (SANs), copolymers of styrene/maleic anhydride (SMAs), a terpolymer of α‐methylstyrene/styrene/acrylonitrile (α‐MS/S/AN), and a copolymer of o‐ and p‐chlorostyrene (PCS). Also, certain simultaneously nitrated‐ and chlorinated‐PPOs (NCPPOs) were found to be miscible with SANs, SMAs and PCS whereas immiscible with the α‐MS/S/AN. The miscibility was indicated by the presence of a single composition‐dependent glass‐transition temperature for a given blend across the entire range of blend compositions tested. The miscibility of the aforementioned NPPOs and NCPPOs blends with SAN1 and SMA1 is attributed to hydrogen bonding of hydroxy groups of NPPOs and NCPPOs with nitrile groups and carbonyl groups, respectively, based on the literature information. The hydroxy groups were generated during nitration and simultaneous nitration/chlorination of PPO as a result of nucleophilic chain scission. Miscible blends of ‐NPPO/SAN and ‐NPPO/SMA with ABS1 showed a substantially better balance of the following properties than a comparable immiscible‐NPPO/SAN blend and a ‐PPO/SAN blend with ABS1: notched Izod impact strength, tensile properties, heat distortion temperature and gasoline stress‐crack resistance.Highlights Nitration and simultaneous nitration/chlorination of PPO generated hydroxyl end groups. Certain NPPOs and NCPPOs were miscible with SANs, SMAs and PCS. Miscibility indicated by a single composition dependent Tg for a given blend. Miscibility attributed to hydrogen bonding of respective functional groups. Impact‐modified miscible‐NPPO/SAN blends and ‐NPPO/SMA blends with ABS1 as impact modifier had good key properties.

Molecular dynamics study on the physical compatibility of SEBS/plasticizer blend systems.

Thermoplastic elastomer styrene-ethylene-butylene-styrene block copolymer (SEBS) has excellent mechanical properties and aging resistance, so it has good application prospects in thermoplastic solid propellants. The selection of plasticizer is one of the keys to the formulation design of thermoplastic solid propellant. The compatibility of the plasticizer with the polymer determines the plasticizer's ability to plasticize the polymer's molecular chain segments. Herein, the compatibility of four plasticizers with SEBS was investigated, and the results declared that the order of compatibility between SEBS and the four plasticizers is SEBS/WO > SEBS/DOS > SEBS/DEP > SEBS/TA. Physical compatibility of SEBS binder with plasticizer triacetin (TA), diethyl phthalate (DEP), dioctyl sebacate (DOS), and 26# industrial white oil (WO) was simulated using molecular dynamics (MD) method via Materials Studio 8.0, and the simulation results were verified experimentally. The results showed that the compatibility of SEBS with these plasticizers can be comprehensively evaluated by analyzing solubility parameters, radial distribution functions, and blend miscibility simulations.

Photoinduced Reversible Disentanglement-Entanglement Transition in partially miscible azobenzene polymer blends

Entanglements, an intrinsic feature of long chains, are critical to the rheological and mechanical properties of polymers. Adding low molecular weight solvents or oligomers into entangled polymers can reduce the entanglements, but the entanglement cannot recover without removing the solvents. Reversible control of the entanglement degree is still a big challenge. In this work, we introduce the azobenzene polymer (Pazo) with reversible photoswitchable side-chain conformation as dynamic diluent into entangled poly(butyl methacrylate) (PBMA) to form a partially miscible blend system. The reduction of entanglement of PBMA by trans-Pazo is similar to a typical solvent, while an unexpectedly stronger tube dilation effect was found for cis-Pazo. Cis-Pazo/PBMA blends exhibit a stronger dependence of plateau modulus on PBMA content, GN(φ)∼φ4.5, which is significantly different from the well-established relation GN(φ)∼φ2 for polymer solutions and blends. The cis-Pazo can disentangle PBMA at a much lower concentration (∼55 %) than the trans-Pazo (>70 %). Pazo content of 55 %–70 % can induce a completely unentangled state of PBMA in Pazo/PBMA blends when Pazo is in the cis state after UV light irradiation, and the entanglement can recover when it is transformed to the trans state. Adding azobenzene polymer does not alter the activation energy of the re-entanglement process.

Miscibility prediction of polylactic acid/polyhydroxyalkanoate blends by molecular dynamics simulations

Blending polylactic acid (PLA) with polyhydroxyalkanoates (PHAs) represents a compelling approach to achieve fully bio-based blends with favorable properties. This work employed molecular dynamics (MD) simulations to study the miscibility of PLA and PHA with different side chain functional groups. The miscibility of the blends was assessed through analyzing snapshots of the blends, pair correlation function, radius of gyration, interaction energy, solubility parameter, and Flory−Huggins interaction parameter. Results revealed that the miscibility with PLA is predominantly affected by the polarity of the side chain functional group of PHA. To achieve effective blending with PLA, it is advisable to use PHAs with non-polar side chain groups. Examination of the glass transition temperature (Tg) for the miscible blends reveals that the rigidity of PLA can be reduced by blending with PHA bearing non-polar side chain functional groups.

High quality 3D printing of low-density polyethylene blends considering the softening effect of polyolefin elastomer

Polyethylene (PE) is one of the most widely used thermoplastics in the polyolefin family. Despite its numerous applications in the industry, particularly in packaging, 3D printing with PE has been a significant challenge that has received little attention. The main obstacles to successful 3D printing with PE are high shrinkage, weak adhesion to the print bed, and weak interlayers. This paper addresses this problem by introducing Polyolefin Elastomer (POE) as an additive in the 3D printing process. Three different POE-LDPE compounds with varying LDPE weight percentages (90%, 70%, and 50%) were 3D printed and analyzed for their mechanical and microstructural properties. The POE and LDPE were blended using the melt mixing method, and the resulting POE-LDPE granules were directly used as input for the FDM machine. The 3D-printed samples were then subjected to DMTA, tensile, compression tests, and SEM imaging. The DMTA results showed that the glass transition temperature of all three samples fell within the range of 71°C to 78°C. Increasing the POE content and decreasing the LDPE amount from 90% to 50% led to a decrease in the storage modulus. In terms of the tensile test results, it was observed that reducing the LDPE amount and increasing the POE content had a toughening effect on the samples, improving their formability and elongation from 1566% for POE-90wt% LDPE to 2112% and 2829% for POE-70wt% LDPE and POE-50wt% LDPE respectively. However, the tensile strength decreased with an increase in the POE amount. For POE-90wt% LDPE, the tensile strength was 14.06 MPa, and for POE-90wt% LDPE, it was just below 13.96 MPa. The compression test revealed that the addition of POE weakened the yield strength of the samples. SEM images demonstrated that the printability of the 3D-printed POE-LDPE samples decreased as the LDPE amount decreased and the POE amount increased. The images also revealed single-phase and miscible blends. These findings suggest the potential emergence of a new, affordable, biocompatible, and recyclable raw material for 3D printing.

Tackling P3HT:Y‐Series Miscibility Through Advanced Processing for Tunable Aggregation

AbstractPolymer and small molecule blend thin films are of strong interest for organic electronics and particularly organic solar cells. The high miscibility in blends of ordinary P3HT and state‐of‐the‐art Y‐series non‐fullerene acceptors (NFAs) suppresses phase separation and aggregation challenging successful charge separation and transport. In a recent work, current‐induced doping (CID) is introduced, a method to precisely control the aggregation of Poly(3‐hexylthiophene) (P3HT) in solution. The highly ordered pre‐aggregation in solution is used here to control the P3HT aggregation in neat films and blends with Y12 (BTP‐4F‐12). This results in a 25‐fold increase in hole mobility in P3HT organic field‐effect transistor (OFET) devices and tunability of the P3HT aggregate quality in the presence of Y12 over large ranges. At the same time, particularly the Y12 long‐range ordering is heavily suppressed by increasing P3HT aggregation. However, solvent vapor annealing (SVA) leads to an extraordinarily high Y12 ordering, changes in the crystal orientation of Y12, and a further improvement of P3HT aggregation. A broad range of different degrees of aggregation of both materials can therefore be obtained in the final thin films solely by changing processing parameters without changing the composition of the material system.

Study of PEG-b-PLA/Eudragit S100 Blends on the Nanoencapsulation of Indigo Carmine Dye and Application in Controlled Release.

A nanocapsule shell of poly(ethylene glycol)-block-poly(d,l-lactic acid) (PEG-b-PLA) mixed with anionic Eudragit S100 (90/10% w/w) was previously used to entrap and define the self-assembly of indigo carmine (IC) within the hydrophilic cavity core. In the present work, binary blends were prepared by solution mixing at different PEG-b-PLA/Eudragit S100 ratios (namely, 100/0, 90/10, 75/25, and 50/50% w/w) to elucidate the role of the capsule shell in tuning the encapsulation of the anionic dye (i.e., IC). The results showed that the higher content of Eudragit S100 in the blend decreases the miscibility of the two polymers due to weak intermolecular interactions between PEG-b-PLA and Eudragit S100. Moreover, with an increase in the amount of Eudragit S100, a higher thermal stability was observed related to the mobility restriction of PEG-b-PLA chains imposed by Eudragit S100. Formulations containing 10 and 25% Eudragit S100 exhibited an optimal interplay of properties between the negative surface charge and the miscibility of the polymer blend. Therefore, the anionic character of the encapsulating agent provides sufficient accumulation of IC molecules in the nanocapsule core, leading to dye aggregates following the self-assembly. At the same time, the blending of the two polymers tunes the IC release properties in the initial stage, achieving slow and controlled release. These findings give important insights into the rational design of polymeric nanosystems containing organic dyes for biomedical applications.

Visualization of isothermal crystallization and phase separation in poly[(R)-3-hydroxybutyrate]/poly(L-lactic acid) by low-frequency Raman imaging

The visualization of the variation of the inter/intra molecular interaction (C = O⋯CH3) between poly[(R)-3-hydroxybutyrate] (PHB) and poly-L-lactic acid (PLLA) in the PHB/PLLA miscible blend during phase separation and crystallization process was successfully investigated using Raman imaging. Images of the blend were developed using high- and low-frequency Raman spectra acquired during the isothermal crystallization of the blend, and both of them were compared. The low-frequency region allowed to observe the changes in the hydrogen bonds between the molecular chains in the blend during phase separation and crystallization via a band at 75 cm−1 derived from PHB. The imaging results obtained using the band at 75 cm−1 due to hydrogen bonding (C = O⋯CH3) between molecular chains were in good agreement with the results obtained using the C = O stretching band at 1720 cm−1. Herein, we demonstrated that the low-frequency region of the Raman spectrum is more sensitive to detecting the start of the phase separation and crystallization of PHB than the corresponding high-frequency region.

Material extrusion of SEEPS blended isotactic PP for possible application as automotive bumper: Performance analysis through Finite Element Simulation

3D processing of isotactic polypropylene or PP based composites through material extrusion is evolving globally as an advanced product development tool for highly specialized sectors like aerospace, biomedicals and automobiles. Conversely, pristine PP shows a severe drawback of exhibiting higher warping compared to other thermoplastics following higher crystalline shrinkage. These have prohibited the wider acceptance of virgin PP in 3D processing for product development. The current investigation is primarily aimed to overcome these disadvantages through mixing with amorphous Poly (styrene-co-(ethylene-co-(ethylene-co-propylene)-co-styrene)) or SEEPS in various mass percentages starting from 10 wt% to 30 wt% in melt before printing. The target was to make a tougher PP with retention of its original strength by reducing the shrinkage; In addition, it is also aimed to predict the usability of such material by virtual testing as a potential alternative to pristine PP for constructing an automotive bumper, designed using an AutoCAD. The printed product (dumbbell) demonstrated a higher toughness and resistance to shrinkage than pristine PP but the tensile strength and modulus decreased significantly beyond 10 wt% loading of SEEPS. Parallelly, at 10 wt% loading, the tensile strength and toughness of the printed products were found to be superior than the compression molded sample. In addition, the printed sample at this loading also possessed lower specific heat (4.79 J/g °C) than the pristine one (5.83 J/g °C) and was more thermally stable (lower degradation rate) than both the pristine and the corresponding higher blend compositions. Due to partial similarity in chemical structure between SEEPS and PP, the former had produced autonomic compatibilization with PP and formed a partially miscible blend. A car bumper was designed from this blend composition (10 wt%) using AutoCAD and its resistances to withstand against the collision stress at high (60 km/h) and low (45 km/h) car speeds were evaluated and compared virtually through Finite Element Simulation (FES) with virgin PP. Due to advantageous properties like retention of tensile strength, higher toughness and thermal stability and lower specific heat, the 10 wt% composition exhibited lesser tendency towards failure by predicting higher deformation than virgin PP. Thus it was found suitable as a bumper material which can be prototyped/finally prepared using materials extrusion technique.

Fabrication of a packaging film based on PLA blends: The evolution of physical, mechanical, and rheological properties

AbstractToday, the use of biodegradable polymers has become widespread in a wide range of industries. This research scrutinized the physical, mechanical, and rheological properties of poly (lactic acid)/poly (ethylene oxide)/carbon nanotube (PLA/PEO/CNTs) blend nanocomposites, as a good candidate for usage in the packaging industry. PEO and CNTs were added at various concentrations to improve the flexibility, toughness, gas permeability, thermal stability, and mechanical properties of PLA via solution blending. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Field Emission Scanning Electron Microscope (FESEM), water contact angle (WCA), rheometric mechanical spectrometer (RMS) test, gas permeability, and tensile characterization were performed to characterize the properties of the prepared blends and nanocomposites. The experimental results revealed that the addition of 25 wt% PEO to the PLA matrix made a partially miscible blend with a droplet‐matrix morphology. PEO at this concentration increased the elongation at break (from 2.2% to 18%) while reducing the modulus (from 25 to 6 MPa). Also, the experimental results indicated that the miscibility of PLA and PEO was enhanced by the addition of 1 wt% CNTs to the prepared blend, associated with diminished entropy of mixing in the LCST phase diagram. Theoretical calculations predicted that the CNTs would be localized in the PLA phase which increased the total crystallinity of the sample by 28%, considerably reducing the amount of gas permeation into the nanocomposite. In addition, the introduction of the CNTs to the blend increased the elongation at break and tensile strength by 13% compared to pure PLA and lowered the rate of thermal degradation effectively. Also, the final results showed that the COOH‐CNTs located in the PEO phase caused a decline in the crystallinity and an increase in the gas permeability of the prepared nanocomposite.Highlights Improvement of physical properties of PLA by blending with PEO and CNTs. A deep investigation on rheological behavior of the prepared nanocomposite. Increasing the crystallinity degree of PLA/PEO blend by adding CNTs. Improvement of the miscibility between PLA and PEO in the presence of CNTs. Controlling the CNTs localization by surface modification.

Poly (ether sulfone) (PES)/polystyrene (PS) Thermoplastic Polymer Blend: Molecular Dynamics (MD) Simulation Methods and Experimental to Miscibility Evaluation

In this study, poly (ether sulfone) (PES)/polystyrene (PS) thermoplastic polymer blend miscibility was looked at using both molecular dynamics (MD) simulations and experiments. In particular, the parameters of the Flory-Huggins interaction and the heat of mixing of poly (ether sulfone) (PES)/polystyrene (PS) blends at different compositions were calculated from MD simulation. For the PES/PS blend, both differential scanning calorimetry (DSC) and MD simulation showed that they are immiscible at PES/PS: 80/20,60/40 ratios. The degree of compatibility of the 20/80 and 40/60 PES/PS blends is higher than that of a PES-rich blend. This thermodynamic behavior was found to be due mainly to intermolecular interactions. Scanning electron microscopy (SEM) results confirmed this observation. Results show that the calculated and#120594; value is positive at the compositions of PES/PS: 80/20 and 60/40, which confirmed that the polymer mixtures were immiscible at these compositions. The miscibility between PES and PS at these ratios is attributed to favorable van der Waals interactions. Also, the results of the DREIDING 2.21 force field show that electrostatic energy, bond angle bending energy, and bond stretching energy may be to blame for the immiscibility of certain composition polymer blends (PES/PS: 80/20 and 60/40).

Spinodal Decomposition of Filled Polymer Blends: The Role of the Osmotic Effect of Fillers.

The reported work addresses the effect of fillers on the thermodynamic stability and miscibility of compressible polymer blends. We calculate the spinodal transition temperature of a filled polymer blend as a function of the interaction energies between the blend species, as well as the blend composition, filler size, and filler volume fraction. The calculation method relies on the developed thermodynamic theory of filled compressible polymer blends. This theory makes it possible to obtain the excess pressure and chemical potential caused by the presence of fillers. As a main result of the reported work, we demonstrate that the presence of neutral (non-adsorbing) fillers can be used to enhance the stability of a polymer blend that shows low critical solution temperature (LCST) behavior. The obtained results highlight the importance of the osmotic effect of fillers on the miscibility of polymer blends. The demonstrated good agreement with the experiment proves that this effect alone can explain the observed filler-induced change in the LCST.

A review on the influence of various metal oxide nanoparticles on structural, morphological, optical, thermal and electrical properties of PVA/PVP blends

Biopolymer blend based nanocomposites have been interestingly investigated by researchers to achieve advanced composite functional materials that are environmentally amicable. Among the varieties of biopolymers, widespread attention has been given to polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) owing to their interesting properties like water solubility, biodegradability, biocompatibility and non-toxicity. PVA and PVP form a completely miscible blend at all compositions as both the polymers are rich in a variety of functional groups that permit effective intermolecular interactions between the polymers as well as with filler. PVA/PVP blend exhibits excellent dopant sensitive properties also. Metal oxide nanoparticles (MONPs) have made a prominent place in the area of scientific and technological research due to their unique chemical and physical properties. Doping with MONPs enhances the properties of the PVA/PVP blend matrix and the resulting PVA/PVP/MONP polymer nanocomposites are suitable for multifunctional purposes. This review mainly focused on the influence of various MONPs such as ZnO, CuO, Al2O3, ZrO2, MnO, SnO, MgO, TiO2, etc. in the structural, morphological, thermal, optical and electrical properties of PVA/PVP blend as well as its applications in various fields.

Fabrication of poly(butylene adipate-co-terephthalate) based films incorporated with carbon nanoparticles: Postharvest shelf-life extension of green chilies (Capsicum annuum L.)

The requirement for recyclable alternatives was prompted to environmental issues caused on by an increase of waste due to the short-term utilization of plastic materials, mostly for food packaging. In this work, a recyclable polymer called poly(butylene adipate-co-terephthalate)—PBAT, which has a small amount of the carbon nanoparticles (CNPs) added to it—one of these choices was studied. Here, we produced PBAT composite film with CNPs as filler utilizing a solution casting method. The composite film was mixed with CNPs in different amounts (1.0, 2.0, 3.0, and 5.0 wt%) while its effects on the film characteristics were examined. FTIR, XRD, and SEM were utilized to study the composition, structure, and sizes of the PBAT/CNPs composites. Adding 3.0 wt% CNPs to the PBAT resulted in a somewhat miscible blend with a droplet-matrix shape, according to the SEM results. The CNPs, enhanced the tensile strength by above 100 %, according to the results of the universal testing machine, and the added CNPs filler was dispersed uniformly within the PBAT. While the mechanical, hydrophobicity, and barrier (O2 and H2O) properties of the PBAT/CNPs composite film were improved, and their microstructures were maintained. With increasing CNPs contents, the films' antimicrobial activity increased; at a 3.0 wt% CNPs level, all of the examined bacteria (S. aureus, and E. coli) had the rate of microbial growth notably increased. Green chilies (Capsicum annuum L.) packed in commercial LDPE film, PBAT/CNPs (PCNB-4) composite film had a shelf-life of 20, and 25 d, respectively, compared to 10 d with control samples. The food quality test results revealed that green chilies could have more extended shelf-life up to 25 d at room temperature—when preserved on the PBAT/CNPs composite film (PCNB-4).