Blends Of Polystyrene Research Articles

Morphology, structure and properties of nonwoven materials obtained by melt electrospinning of polypropylene–polystyrene blends

AbstractMelt electrospinning is a convenient method for producing nonwoven materials from polymers with limited solubility, such as polyolefins and its blends. In this work, we investigated the process of electrospinning from melt of blends of thermodynamically immiscible polymers: polypropylene and polystyrene. Nonwoven materials with an average fiber diameter of 1.5–4 μm have been obtained. Typically, morphology of blended nonwoven material can be further modified by selective removal of one of the components. However, it was found that after removal of polystyrene from the produced materials, the fibers do not undergo significant changes in the surface morphology. At the same time, fiber fragments having a length of 5–100 μm appear and their number grows as the content of polystyrene in the initial material increases. According to X‐ray data, the supramolecular structure of polypropylene changes in the electrospinning process: a transition from a stable α‐form to a low‐ordered mesophase occurs. On the other hand, a reverse transition to crystallites of the α‐form of polypropylene was observed after polystyrene was removed with hot chloroform. All materials exhibit superhydrophobic properties and their wetting occurs according to the Wenzel model. Sorption capacity of the resulting materials is up to 90 g/g for motor oil.

Thermomechanical Degradation of Polypropylene – Polystyrene Blends During Extrusion‐Based Melt Blending – A First Survey of Shear‐Induced Molecular Architecture Changes

AbstractPolymer blends made of plastic waste and manufactured by extrusion‐based melt blending are of particular importance for mechanical recycling in the context of tailoring material properties for value‐added applications. For both, property tailoring and for suppressing downcycling, it is inevitable to understand the thermomechanical degradation behavior of the blends, induced by melt‐blending. In this investigation, the thermomechanical degradation of polypropylene (PP) – polystyrene (PS) blends are analyzed for different blend compositions based on cross‐fractionation chromatography. This method allows for the first time to separate PP from PS with simultaneously analyzing the change in the molecular architecture distribution due to thermomechanical degradation. It is revealed that the melt‐blending induced degradation effect is primarily occurring in PP, where besides a reduction of chain length, significant chain irregularities are generated. It is observed that PP degradation is increasing with a growing proportion of PS. These new findings offer the first insights into the thermomechanical degradation of PP/PS blends.

Crystallization and polymorphic behaviour of melt miscible blends of crystalline homopolymers with close melting temperatures under confinement

The confined crystallization behavior of the crystalline/crystalline blends of poly(ethylene oxide) (PEO) and poly(butylene adipate) (PBA) in the electrospun nanofibers fabricated from the ternary blends of polystyrene (PS), PEO, and PBA, where PS was present as the majority component, was investigated. The electrospun nanofibers had PS as the matrix whereas the PEO/PBA mixed phase, with total weight fraction of 0.2 or less, constituted the dispersed domains having sizes of the order of only few hundred nanometers. Hence, the crystallization induced phase separation of PEO and PBA occurred within the confined domains. Despite extremely close melting temperature of PEO and PBA, faster crystallization kinetics of PEO led to entrapment of PBA in the intraspherultic regions of the former. Hence, further crystallization of PBA occurred under hierarchical confinement where the larger and smaller length-scale confinements were imposed by the glassy PS matrix and PEO crystals, respectively. Such a scenario resulted in crystallization occurring both via homogenous as well as heterogeneous crystallization mechanism. Interestingly, the homogenous nucleation of PEO was suppressed whereas the heterogeneous nucleation was enhanced in the ternary blend nanofibers even at very low weight fraction. Most significantly, it was observed, that during melt-recrystallization, memory of chain orientation is retained which favoured the formation of α-crystals in PBA. The present study highlights the role of confinement as well as chain orientation, on the crystallization behaviour, in crystalline/crystalline blend systems for which limited studies have been done so far.

Visualization of Macrophase Separation and Transformation in Immiscible Polymer Blends

Visualization of Macrophase Separation and Transformation in Immiscible Polymer Blends

Janus micro‐thread to micro‐nanodroplets using dynamic contact line lithography

AbstractDynamic contact line lithography (DCLL) is generally used for the template‐less but well‐ordered deposition of polymer micro/nanostructures from the solution of homopolymer. DCLL from the blend of several polymers in a common suitable solvent can generate rich morphologies including nanostructured Janus micro threads on a surface which might be challenging to fabricate using any other method. A blend of polystyrene (PS) and poly(methyl methacrylate) (PMMA) in toluene with different compositions and concentrations are used for DCLL at a constant contact line speed of 10 μm/s. Variations of compositions and the overall concentration of polymer, engender Janus micro threads to undulated threads and multi‐layered micro/nanodroplets of PS/PMMA. Interestingly, the more soluble PS phase separates first compared to less soluble PMMA near the contact line due to the enhanced local concentration of PS during the convective flow of the solvent toward the contact line. This is also verified by DCLL using PS/PMMA blend in ethyl acetate as well. In that case, more soluble PMMA deposits first near the contact line compared to marginally less soluble PS in the solvent.

A Component Content Measurement Method Modified Using Indirect Hard Modeling for Polymer Blends Based on Raman Spectroscopy.

Raman spectroscopy has been proven to be useful for the component content measurement of polymer blends. However, the soft modeling methods commonly used in quantitative analysis of Raman spectroscopy require a large number of training samples, resulting in a waste of materials and time. This work adopted a modified indirect hard modeling (IHM) method to measure the component content of polymer blends based on Raman spectroscopy. The Raman spectra of polypropylene (PP)/polystyrene (PS) blends with different component content were collected and resolved into the sum of multiple Voigt peak functions. For a large number of peak parameters, the two-dimensional correlation spectroscopy was used to screen out the characteristic Voigt peaks highly correlated with component content to reduce the parameter dimensions and build the parameterized spectral models. The spectral model of the blend was expressed as the weighted sum of the pure component spectral models, during which the parameters of the pure component models were adjusted within a range. According to the relationship between the weight and content of the pure component, a linear regression model for component content prediction was established. The coefficient of determination (R2)/root mean squared error of the IHM component content prediction model was 0.9931/0.4367 wt%. Besides, two popular soft modeling methods, partial least squares and artificial neural network, were compared with the IHM method, which showed that the IHM model had higher prediction accuracy with fewer training samples.

The synthesis of functional Janus nanosheets as compatibilizers for the immiscible polyamide 6 /polystyrene (PA6/PS): Formation of the nanosilica monolayer at the interface

The non-spherical Janus nanosheets (JNSs) have been large-scale synthesized by grafting polystyrene (PS) chains and epoxy group on the opposite sides of JNS, denoted as epoxy-silica-PS JNS. The functional JNSs are employed as compatibilizer in the immiscible polyamide 6 (PA6)/polystyrene (PS) blend. In the melt-blending process, the JNS with epoxy group can react with carboxyl (amino)-capped PA6 and in-situ form the PA6-silica-PS JNS. Owing to the amphiphilicity and Pickering effect, the JNSs can be exclusively located at the polymeric interface and assemble into the nanosilica monolayer at 0.5 wt% loading. With increasing the JNSs loading, the size of dispersed PS phase is decreased gradually and the JNSs still maintain the single layer structure at the interface. The dynamic moduli of the blends have been effectively improved for the JNSs at the interface. This report provides an extended application of Janus nanosheets to stabilize and functionalize the polymeric interface.

Red-shifted optical absorption in films of azo-polyurea - polystyrene blends: Structural correlations and implications

We report the optical absorption characteristics in thin film coatings of a blend of two polymers: azo-polyurea (azo-PU) and polystyrene (PS). It is shown using UV–visible spectroscopy that the absorption spectrum of the resultant blend undergoes a distinct and decisive redshift towards the visible wavelength regime, accompanied by broadening and overlapping of the characteristic absorption peaks. Light exposure studies reveal that the red-shifted optical absorption induces trans to cis isomerization of the blended polymer films upon exposure to visible wavelengths, which would otherwise occur typically only by stimulus from ultraviolet wavelengths. The extent of redshift in the absorption maxima and broadening in the absorption spectrum of the polymer blend films are found to be sensitive to the amounts of the constituent polymers. The changes in spectral configuration are understood in terms of lattice structural changes that occur in azo-PU chains due to the incorporation of PS, in particular the disarrangement in hydrogen bonding. It is suggested that the modified optical absorption characteristics would endow significant advantages, such as the possibility of replacing UV with visible light in applications requiring cis → trans and trans → cis isomerization, as well as photoswitchability due to trans-cis-trans cycling.

Microstructural, functional groups and textural analysis of expanded polyethylene reinforced polystyrene composites with recycled aluminium as ternary component

Abstract The aim of this study is to utilise recycled aluminium, expanded polyethylene (EPE) and expanded polystyrene (EPS) to develop a ternary composite. The study was a preliminary investigation into the microstructural, functional groups and textural properties of the novel material. The material was characterised by Fourier Transform Infra-Red Spectroscopy (FTIR), Scanning Electron Microscopy with Energy Dispersive X-ray analysis (SEM-EDX) and Branueur-Emmet-Teller analysis (BET). The shifts in the FTIR peaks for each of the polymer feedstock in comparison with the binary composite indicated chemical interactions between them. For the ternary composites, there were shifting of peaks as the proportion of the aluminium increased in the composites, suggesting the influence of aluminium on the curing process. Beyond 20% Al filler, there were no significant functional group changes in the composite. SEM revealed that an increase in aluminium filler percentage led to better interfacial adhesion and dispersion. BET revealed that the blend of polystyrene and powdered EPE reduces the surface area, while the introduction of the aluminium particles within the range observed increases the surface area of the hybrid composites formed. As the dispersion of aluminium increased, pore volume increased while pore size decreased.

Fabrication of Highly Photostable Polystyrene Films Embedded with Organometallic Complexes.

Polystyrene is a common thermoplastic and is produced in different shapes and forms. The scale of manufacture of polystyrene has grown over the years because of its numerous applications and low cost of production. However, it is flammable, brittle, has low resistance to chemicals, and is susceptible to photodegradation on exposure to ultraviolet radiation. There is therefore scope to improve the properties of polystyrene and to extend its useful lifetime. The current work reports the synthesis of organometallic complexes and investigates their use as photostabilizers for polystyrene. The reaction of excess ibuprofen sodium salt and appropriate metal chlorides in boiling methanol gave the corresponding complexes excellent yields. The organometallic complexes (0.5% by weight) were added to polystyrene and homogenous thin films were made. The polystyrene films blended with metal complexes were irradiated with ultraviolet light for extended periods of time and the stabilizing effects of the additives were assessed. The infrared spectroscopy, weight loss, depression in molecular weight, and surface morphology of the irradiated blends containing organometallic complexes were investigated. All the synthesized organometallic complexes acted as photostabilizers for polystyrene. The damage (e.g., formation of small polymeric fragments, decrease in weight and molecular weight, and irregularities in the surface) that took place in the polystyrene blends was much lower in comparison to the pure polystyrene film. The manganese-containing complex was very effective in stabilizing polystyrene and was superior to cobalt and nickel complexes.

Reversible Photo-Induced Reshaping of Imprinted Microstructures Using a Low Molecular Azo Dye.

A blend of low molecular azo glass (AZOPD) and polystyrene (PS) were used for the systematic investigation of photo-induced stretching and recovery of nanoimprinted structures. For this purpose, light and heat was used as recovery stimuli. The AZOPD/PS microstructures, fabricated with thermal nanoimprint lithography (tNIL), comprises three different shapes (circles, crosses and squares) and various concentrations of AZOPD fractions. The results show a concentration-dependent reshaping. Particularly the sample with 43 w-% of the AZOPD fraction have shown the best controllable recovery for the used parameters. A possible explanation for shape recovery might be the stabilizing effect of the PS-matrix.

Miscibility and thermal behavior of poly(methyl methacrylate) and polystyrene blend using benzene as a common solvent.

Polymer blending is one of the advanced technologies to attain polymeric material with tailored properties. In this work, the miscibility of Poly(methyl methacrylate) (PMMA) and Polystyrene (PS) blend in benzene was investigated by employing various techniques such as FTIR spectroscopy, viscosity measurement technique, light scattering techniques, DSC and TGA techniques over an extended range of concentrations, compositions, and temperatures. The results revealed that there exist hydrogen bonding and hydrodynamic interactions which led these polymers to get miscible to a large extent. The compatibility increased with the increasing PS contents or increase in temperature of the system. In addition, the thermal stability of blends was found to be improved with the increase in the compatibility of the polymer.

Effect of particle size on TiO2-polystyrene nanoparticles contact angle for hydrophobicity behavior

The physical chemistry and surface science is being exploited in the recent days excessively so as to control the surface roughness, thus having a control over the hydrophobicity of the surface. Hydrophobicity is the resistance of the water to adsorb on the surface. It can be done by the making the surface rough either through particle deposition or Nano-structure machining on the surface. In most of the research, bare or unadulterated Nano particles give inferior results. Silated, hydroxylated, hydrolyzed or polymerized nanoparticles for experimenting with hydrophobicity has become a trend. Even for a single nanoparticle, it is possible to obtain the precise measurement for different contact angle with respect to the droplet size. In this work, Nano particle deposition is studied and modified Nano particles are used. The chemically modified TiO2 nanoparticles gave excellent hydrophobic results. The two different TiO2 nanoparticle size are synthesized via ball milling; each trial having three samples with different proportions of polystyrene (PS) blend TiO2 nanoparticles were prepared using sol gel process. Subsequently stainless steel substrate is dipped in the nanoparticle mixture and dried. The surface roughness, contact angle is measured. The influence of various TiO2 particle size concentrations in the hydrophobicity performance is compared and discussed.

Quantifying nanoscale forces using machine learning in dynamic atomic force microscopy.

Dynamic atomic force microscopy (AFM) is a key platform that enables topological and nanomechanical characterization of novel materials. This is achieved by linking the nanoscale forces that exist between the AFM tip and the sample to specific mathematical functions through modeling. However, the main challenge in dynamic AFM is to quantify these nanoscale forces without the use of complex models that are routinely used to explain the physics of tip–sample interaction. Here, we make use of machine learning and data science to characterize tip–sample forces purely from experimental data with sub-microsecond resolution. Our machine learning approach is first trained on standard AFM models and then showcased experimentally on a polymer blend of polystyrene (PS) and low density polyethylene (LDPE) sample. Using this algorithm we probe the complex physics of tip–sample contact in polymers, estimate elasticity, and provide insight into energy dissipation during contact. Our study opens a new route in dynamic AFM characterization where machine learning can be combined with experimental methodologies to probe transient processes involved in phase transformation as well as complex chemical and biological phenomena in real-time.

A no-hysteresis TIPS–pentacene:polystyrene blend-based organic field effect transistor by extruded direct ink writing and the application in a resistive load inverter circuit

Organic field effect transistors (OFETs), with the active layer made from 6,13-bis(triisopropylsilylethinyl) pentacene:polystyrene blend films, were fabricated on rigid (glass) and flexible (polyethylene terephthalate) substrates using a motor-controlled extrusion-based Direct Ink Writing printing method.

Tuning phase separation morphology in blend thin films using well-defined linear (multi)block copolymers

Tuning phase separation morphology in polymer blend thin films is a promising strategy to improve their properties. In this study, a series of poly(n-butyl methacrylate)-b-polystyrene linear copolymers with the same overall degree of polymerization but different number of blocks are synthesized by macroRAFT-mediated emulsion polymerization, and used as compatibilizers in poly(n-butyl methacrylate)/polystyrene blend thin films with thickness of ca. 20 nm. It is verified that multiblock copolymer is more effective to diminish the size of phase separation domains compared to diblock copolymer. Self-consistent field simulation agrees with the experimental results, and demonstrates that the compatibilization behaviors of diblock and multiblock copolymers are different. Diblock copolymer can compatibilize the blend well at a higher content, whereas multiblock copolymers tend to give a smaller domain size but less homogeneous morphology. In addition, simulation results show that copolymers with a longer block length would produce a narrower interface, which may weaken the penetration of block copolymers into their corresponding phases. This study provides a pioneering attempt in clarifying the effect of block copolymers on blend phase separation morphology, and it will be of practical value in obtaining desirable mechanical properties of polymer thin films.

Antialgal Synergistic Polystyrene Blended with Polyethylene Glycol and Silver Sulfadiazine for Healthcare Applications

Polystyrene (PS) was blended with polyethylene glycol (PEG) and silver sulfadiazine (SS) with different weight proportions to form polymeric blends. These synthesized blends were preliminary characterized in terms of functional groups through the FTIR technique. All compositions were subjected to thermogravimetric analysis for studying thermal transition and were founded thermally stable even at 280°C. The zeta potential and average diameter of algal strains of Dictyosphaerium sp. (DHM1), Dictyosphaerium sp. (DHM2), and Pectinodesmus sp. (PHM3) were measured to be -32.7 mV, -33.0 mV, and -25.7 mV and 179.6 nm, 102.6 nm, and 70.4 nm, respectively. Upon incorporation of PEG and SS into PS blends, contact angles were decreased while hydrophilicity and surface energy were increased. However, increase of surface energy did not led to decrease of antialgal activities. This has indicated that biofilm adhesion is not a major antialgal factor in these blended materials. The synergetic effect of PEG and SS in PS blends has exhibited significant antialgal activity via the agar disk diffusion method. The PSPS10 composition with 10 w / w % PEG and 10 w / w % SS has exhibited highest inhibition zones 10.8 mm, 10.8 mm, and 11.3 mm against algal strains DHM1, DHM2, and DHM3, respectively. This thermally stable polystyrene blends with improved antialgal properties have potential for a wide range of applications including marine coatings.

Morphology and Charge Transport Properties of P(NDI2OD-T2)/Polystyrene Blends

While the strategy of blending commodity insulating polymers with conjugated polymers has been previously applied to modify the properties of organic field-effect transistors (OFETs), comprehensive studies on the evolution of morphology and OFET performance with film composition are scarce. In this contribution, films comprising the n-type semiconducting polymer P(NDI2OD-T2) and the insulating polymer polystyrene (PS) are explored in detail. In particular, the electrical properties and film morphology of blends with a P(NDI2OD-T2) concentration ranging from 0.125 to 100 wt % are studied. Two regimes characterized by distinct dependencies of device mobility as a function of P(NDI2OD-T2) content are observed: Above 12.5 wt % P(NDI2OD-T2), the OFET mobility exhibits a weak dependence on P(NDI2OD-T2) concentration despite the presence of strong lateral phase separation, while below 12.5%, the device mobility is observed to decrease strongly with decreasing P(NDI2OD-T2) concentration attributed to disrupted surface connectivity of the P(NDI2OD-T2) phase. UV–vis absorption spectroscopy and grazing incidence wide-angle X-ray scattering (GIWAXS) measurements indicate that the aggregation and crystalline packing are not strongly affected by the presence of PS. Atomic force microscopy and scanning transmission X-ray spectro-microscopy reveal lateral phase separation for blends with compositions of 87.5 to 25 wt % P(NDI2OD-T2). Enrichment of P(NDI2OD-T2) at the film surface is confirmed by near-edge X-ray absorption fine structure spectroscopy, with a high P(NDI2OD-T2) surface composition (>80 wt %) maintained down to an overall blend composition of 12.5 wt % P(NDI2OD-T2). The strong decrease in OFET mobility for P(NDI2OD-T2) concentration less than 25 wt % is attributed to a loss of P(NDI2OD-T2) surface connectivity at low P(NDI2OD-T2) loading. We also observe a transition from face-on to edge-on dominated configuration at low P(NDI2OD-T2) content with GIWAXS, consistent with an edge-on surface layer that persists down to monolayer surface coverage.

Reinforcing and toughening blends of recycled acrylonitrile-butadiene-styrene/recycled high-impact polystyrene through ionic crosslinking

With the increasing attention to environmental pollution, the recycling and modification of wasted plastics has attracted more and more attention. In this study, zinc dimethacrylate (ZDMA) was first used to introduce ionic crosslinking into recycled acrylonitrile-butadiene-styrene (rABS)/recycled high-impact polystyrene (rHIPS) blends. On one hand, ZDMA underwent self-polymerization to form poly-ZDMA (PZDMA) particles. On the other hand, ionic crosslinks were formed by grafting with butadiene on the rABS or rHIPS chains of ZDMA. The ionic interaction between Zn2+ and unsaturated carboxylate was used to improve the compatibility between rABS and rHIPS. The enhanced impact strength, tensile strength, storage modulus and loss modulus of the blends were observed. In the case of 4 wt% ZDMA, the notched impact strength was 8.71 kJ/m2, 133% higher than that of blends without ZDMA. Scanning electron microscope (SEM) showed that polybutadiene (PB) had a good dispersion in rABS/rHIPS blends, the interface between rABS and rHIPS was indistinct, suggesting good compatibility. This indicated that the compatibility of rABS/rHIPS blends can be improved by using ion crosslinking.

Microstructural and Physical Properties of Thermoplastic Corn Starch/Polystyrene Blend Foams Affected by Different Contents and Combinations of Plasticizers

A comprehensive study was performed on thermoplastic corn starch (TPS)/polystyrene (PS) blend foam to optimize the formulation from the aspects of plasticizer content and the blend ratio. Plasticization of native starch was implemented with various contents of plasticizer [water (W) + glycerol (G)], 21, 23, 25 and 29%, and W/G ratio of 1/2, 2/3, 3/2 and 2/1 using melt extrusion process. The influence of plasticizer loading content and also its combination on the microstructural and physical properties of the blend foam were investigated. The morphological consideration was also carried out by scanning electron microscopy to evaluate the distribution and regularity of the foam cells. The results showed that water had a desirable effect on the cell parameters in W + G = 21 and 29%. In the following, full factorial method in Minitab software was used to optimize the formulation according to the properties. Moreover, the effect of PS content on the moisture absorption and cell structure of TPS/PS blend foam was evaluated. In addition, the blend ratio of 20/80 was obtained as an optimum ratio for the TPS/PS blend foam via evaluating the effect of different contents of PS on the moisture absorption amount and cell structure of the blend foam. The addition of 20% PS to TPS caused to 6 times higher expansion ratio than PS and 60% higher than TPS, while 50% lower moisture absorption than TPS. This combination can be a good alternative candidate for warm food packing applications.