Polymerization Of Styrene Monomers Research Articles

Cellular response of THP-1 macrophages to polystyrene microplastics exposure

Microplastic in the environment have the capability to reach the human immune system via the ingestion, inhalation and direct contact. Polystyrene (PS) is one of the most widely used plastics, which is made up by polymerization of styrene monomers. Mounting evidences on the presence of microplastics in blood clearly indicate their access to macrophages that are major component of the immune system. However, data on the response of macrophages to microplastics exposure are limited. Our study reports the response of human macrophages transformed by PMA (phorbol 12-myristrate 13-acetate) to exposure to PSNPs of size range (≤ 450 nm). The polystyrene particles utilized in this study, were formulated from beads to powder by grinding and filtering the particles to acquire a range of size ≤ 450 nm particles with deionized water. This size variation used in this experiment imitates the size of plastic that humans can ingest plastic particles through food that gets fragmented from plastic cups and plates. Here we report that exposure to PSNPs (50–500 µg/mL) significantly decreased the viability of human macrophages. In addition, PSNPs (500 µg/mL) induced oxidative stress and decrease cell proliferation. Exposure to PSNPs decrease the membrane potential of mitochondria and caused damage to the DNA of macrophages. Overall, our study reports the differential toxic effects of PSNPs on human macrophages, delineating the potential risks of PSNPs exposure to human health.

Evaluation of moisture diffusion as a threat to polymer/inorganic nanoparticles composites properties: Polystyrene/calcium sulfate nanocomposite as a case study

The present study aims to investigate the water diffusivity into polystyrene/ calcium sulfate (PS/CaSO4) nanocomposite samples as a threat to the intended reinforcing properties. For this purpose, CaSO4 nanoparticles were synthesized through a chemical reaction using polyethylene glycol as the stabilizing agent. The polystyrene/calcium sulfate nanocomposites were fabricated through in situ polymerization of styrene monomer and stearic acid coated CaSO4 nanoparticles. SEM analysis was applied to determine the size and shape of the produced nanoparticles. In addition, TEM analysis was applied to study the general morphology and structure of the nanocomposites in order to confirm the PS/CaSO4 nanocomposites formation. FTIR analysis was employed to study the surface functions and bonds formation in both the surface treatment and nanocomposite preparation steps. Water diffusivity into the nanocomposites was evaluated through samples water exposure followed by calculation of the effective diffusion coefficients (Deff) using the diffusion equation given by Fick’s 2nd law. The calculation results have revealed that the obtained Deff values for water diffusivity in PS/CaSO4 (1.5 wt.%) and pure PS samples were 8.73 × 10−20 and 11.1 × 10−20 m2/s, respectively.

Simultaneously enhancing the thermal conductivity and dielectric constant of BN/CF hybrid filled polypropylene/polystyrene composites via in situ reactive processing

AbstractThermal conductive and electrical insulating polymer composites are exerted a tremendous fascination on the field of thermal management. The effective utilization of fillers is indispensable to construct the thermal conductive pathway to fabricate high thermal conductive polymer composites. Herein, a facile approach involves selective localization of boron nitride (BN) and carbon fiber (CF) through in situ polymerization of styrene through reactive processing as well as double‐percolation structure design. These composites can be easily fabricated by blending the BN, CF with polystyrene during the polymerization of styrene monomer and secondary compounding with polypropylene (PP). The selective localization of BN and CF was observed by scanning electron microscope (SEM) characterization. The cocontinuous structure of PP/PS was also confirmed by SEM observation. The thermal conductivity values was promoted from 0.22 W/mk for PP/PS blends to 0.62 W/mk for the in situ reactive blending composites with 14.5 wt% BN and 18 wt% CF. Moreover, the dielectric properties were also higher than that of the simple melt blending composites. Therefore, the method we proposed provides a potentially feasible plan to design and prepare the thermal conductive and electrical insulating composites for thermal management applications.

Comparison of residual styrene monomer determination of pharmaceutical materials packed with polystyrene using gas chromatography and ultraviolet/visible spectrophotometer

Background: Plastics such as plastic wrapping are an integral part of today’s society. Plastics are made by polymerization of styrene monomers. If the polymerization reaction is not perfect, then there will be unreacted monomer residues. Although styrene is still considered harmless, if there is a metabolic process will form styrene oxide that can cause effects that are carcinogenic. Aims and Objectives: This study aims to determine the residue of pharmaceutical styrene materials packed with polystyrene using gas chromatography (GC) and ultraviolet (UV)/visible spectrophotometers which are usually available in chemical analysis laboratories. Materials and Methods: Orientation of analysis method was performed using latex polystyrene sample. Styrene monomer analysis was performed using a GC and UV/visible spectrophotometer. Then a comparative study was conducted on both methods. Once this method was accepted, it was applied to a polystyrene-containing sample obtained from the market. Styrene was isolated from the sample; then, both methods were tested and compared. Results: Using polystyrene latex sample and varying column temperature, for GC, the optimum condition was obtained at column temperature 110°C, detector temperature 200°C, and temperature of injector 200°C. Using the packing column, we got a repeatability of 96.67%, PRECISION test of 2.81%, 96.49% recovery test, and a detection limit of 0.25 ppm. For the quantitative test of latex polystyrene samples, the average residual content obtained was 0.276%. When using GC with a capillary column, used column DB-17 at 110°C, detector, and injector temperature at 200°C, the average content of styrene residue was 0.278%. When using the spectrophotometer UV/visible, λ maximum at 280.5 nm, the reliability, assay, recovery test, and detection limits were 94.83%, 4.36%, 93.72% and 0.30 ppm, respectively. The residual styrene results obtained with this instrument was an average of 0.271%. Using variance analysis with the fixed model for all three methods (GC with the capillary column, GC with packing column, and spectrophotometer UV/visible) obtained H0 hypothesis was rejected so that it was continued with Duncan test with the result of all three methods could be used for analysis of styrene residue. The result of average analysis for beverage sample with Spectrophotometer UV/visible method was 0.0220%, packed column GC was 0.0221% packing, and capillary column GC of 0.0.223%. For medication samples in each instruments were found 0.0239%, 0.0241%, and 0.0242%, whereas for food samples obtained 0.0236%, 0.0238%, and 0.0239%. Conclusions: A GC method with either a packing column or a capillary column and a spectrophotometer UV/visible could be used to analyze the residual styrene monomer of a polystyrene-grade pharmaceutical sample. The best analysis could use GC with a capillary column. It is recommended to use differential scanning calorimetry and thermogravimetric analysis, if available, as well as infrared spectrophotometer to obtain a cheaper and better method.

Preparation of Graphene Encapsulated Silicon Nanoball.

Concerning application of graphene, a lot of efforts have been made to improve performance of nanomaterials in many fields, such as electric and electronic devices. Some examples are preparation of 3-dimension structured nanomaterials like nanoballs by CVD process and hybridizing with silicon. These graphene-based materials are proven to be available for secondary battery, EMI and ACF in electronics. Especially, some research has shown that they were very effective to enhance safety and volumetric capacity when they were used as anode materials of secondary battery. Although graphite and its compound with metal have been used as an anode material due to their high stability and reversibility, it still has lower charge capacity. On the contrary, silicon is known as a material which increases the charge capacity up to four times, compared with carbon-based materials, but it has lower stability and reversibility. For that reason, a few researchers just started to improve the charge capacity by hybridization of carbon-based material with silicon. In this paper, we prepared nanocarbon based material which has a new structure of graphene encapsulated silicon nanoball as an anode material which is applicable to high-capacity secondary battery. In order to form a graphene encapsulated silicon nanoballs, the polystyrene encapsulated silicon nanoballs were prepared by emulsion polymerization of styrene monomer with silicon nanoparticles. The resulting nanoballs were immersed in iron chloride solution and then dried. Finally they were treated in high temperature through CVD and etched by hydrogen chloride. Morphology of the graphene encapsulated silicon nanoballs was observed by the field emission scanning electron microscope (FESEM) and the field emission transmission electron microscope (FETEM) to search for core-shell structured nanoball. Spherical structure of graphene encapsulated silicon nanoball was investigated by the Raman, the X-ray Photoelectron Spectroscopy to identify graphene layers on the surface of the inner silicon core.

Impact of non-ionic surfactant chemical structure on morphology and stability of polystyrene nanocomposite latex

Polystyrene (PS) colloid particles in presence of non-ionic surfactant-modified clay particles were prepared by the free-radical polymerization of styrene monomers in emulsion. Three different types of non-ionic surfactants, sorbitan monopalmitate (Span®40), polyethylene glycol octadecyl ether (Brij®S10), and polyoxyethylene (9) nonylphenylether (Igepal®Co-630) were used for the preparation of surfactant-modified clay. High-resolution transmission electron microscopy studies showed that few colloid PS particles with clay mineral layers at the surface were obtained; the particle sizes were observed to be in the micrometer size range, and stable dispersions were obtained when Span®40 and Igepal®Co-630 modified clay minerals were used as stabilizers. The clay mineral particles were observed to be mostly encapsulated by PS latex particles, and a typical morphology was observed when Brij®S10-modified clay was used as a stabilizer. This strategy can be applied to develop stable polymer latex particles via emulsion polymerization.

Conductive films based on composite polymers containing ionic liquids absorbed on crosslinked polymeric ionic-like liquids (SILLPs)

Polymerization of styrenic monomers containing imidazolium subunits in the presence of crosslinking monomers and using ionic liquids (ILs) as porogenic agents provides composite materials with excellent mechanical properties and displaying conductivities that are in the same order of magnitude than those shown by bulk ILs. This approach allows the use of high crosslinking degrees and low IL-loadings without compromising the required properties of the resulting composites. Besides, no appreciable leaching of the bulk IL component is detected.

Synthesis and polymerization of styrene monomers bearing spiroorthoester structure and volume change during crosslinking by double ring-opening of the pendant spiroorthoesters of the obtained polymers

Synthesis and polymerization of styrene monomers bearing spiroorthoester structure and volume change during crosslinking by double ring-opening of the pendant spiroorthoesters of the obtained polymers

Preparation and Utilization of Polystyrene Nanocomposites Based on TiO2 Nanowires

Successful preparation of titanium dioxide nanowires (TiO2-NWs), by a hydrothermal method, then embraced in polystyrene (PS) to form nanocomposites using emulsion polymerization of styrene monomer in presence of different ratios of TiO2 nanowires. The morphology and crystalline structure of the prepared TiO2 were proved by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The thermal stability of the nanocomposites, measured by thermogravimetric analysis (TGA), was found to be upgraded especially at higher loading %s of the nanowires irrespective to pure polystyrene. Furthermore, polystyrene nanocomposites (modified with 4%, 8% and 12% of TiO2 nanowires) were used to remove organochlorine pesticide (OCPs) residues from contaminated water. GLC results showed that the pristine TiO2 nanowires has a poor affinity for removing OCPs residues (from 8.82 to 70%), whereas polystyrene/TiO2-NWs nanocomposites are powerful material for removing OCPs residues (61.76 to 98.64%) due to changing of TiO2 nanowires surfaces from completely hydrophilic to hydrophobic structure as proven by contact angle results. These nanocomposites materials can be used for packaging application and the mainly application of these materials in a water filter, which may be a promising and economically feasible technology for wastewater purification.

Synthesis of additive-free cationic polystyrene particles with controllable size for hollow template applications

Studies on the synthesis of organic particles for template applications for facilitating the production of hollow particles have attracted tremendous attention. The unavailability of the commercial templates with a positive zeta charge is the main reason for this demand of study. The purpose of this study was to spotlight the synthesis of pure and cationic polystyrene (PS) particles with controllable size (from 30 to 300nm) using a single step and relatively simple and cheap process and to demonstrate their application as the template in the production of hollow inorganic particles. Different from other methods, the synthesis method was based on the polymerization of styrene monomer in an aqueous solution system in the absence of any additional components (polymers, surfactants, chemicals, etc.) under 2,2-azobis (isobutyramidine) dihydrochloride (AIBA) as a cationic initiator to facilitate the creation of PS with a positive zeta charge. Precise control of the PS particle size in the nanometer range was achieved by the adjustment of reaction parameters (i.e. temperature, and styrene and AIBA concentrations). The size of the PS particles was proportional to the composition of styrene and the amount of initiator but had an inverse-proportional trend to the temperature. In addition, we also found that the styrene amount had more effect than the initiator (more than 4 times) on controlling PS size. Since an FTIR pattern and a micro-Raman spectrum results detected that the prepared PS particles had pure composition and homopolymer in spite of varying reaction parameters, the change of the particle size was due to changes in nucleus formation and particle growth rates. Flexibility of the process in the nanometer size control also drove to the devise of an equation to predict the particle size, which would be important for further scale-up development. Finally, the loaded positive zeta charge in the PS made it possible to assist the production of hollow inorganic particles (e.g. tungsten oxide, zirconia, and silica), in which this production could not be achieved when using commercial PS particles, verified by the particle formation mechanism hypothesis.

Anion exchange membranes based on semi-interpenetrating polymer network of quaternized chitosan and polystyrene

Anion exchange membranes with semi-interpenetrating polymer network (semi-IPN) were prepared based on quaternized chitosan (QCS) and polystyrene (PS). The PS was synthesized by polymerization of styrene monomers in the emulsion of the QCS in an acetic acid aqueous solution under nitrogen atmosphere at elevated temperatures. The semi-IPN system was formed by post-cross-linking of the QCS. A hydroxyl ionic conductivity of 2.80×10−2Scm−1 at 80°C and a tensile stress at break of 20.0MPa at room temperature were reached, respectively, by the semi-IPN membrane containing 21wt.% of the PS. The durability of the semi-IPN membrane in alkaline solutions was tested by monitoring the variation of the conductivity and the mechanical strength. The degradation of the conductivity at 80°C was about 5% by immersing the membrane in a 1molL−1 KOH solution at room temperature for 72h and at 60°C for 50h, respectively. The tensile stress at break at room temperature could maintain about 20.0MPa for the membrane soaking in a 10molL−1 KOH solution at ambient temperature for more than 70h. The water swelling of the semi-IPN membranes was discussed based on the stress relaxation model of polymer chains, and it obeyed the Schott’s second-order swelling kinetics.

Polystyrene latex synthesized in presence of ultrasonic initiation

AbstractThe low water solubility of styrene (St) monomer increase the need for a good initiator system to speed up the emulsion polymerization and remove unreacted monomers. Polymerization of styrene monomer in water was performed at 30, 50, and 70°C under ultrasonic irradiation using sodium dodecyl sulfate as surfactant and ammonium persulfate as initiator. Ultrasonic energy was used as a tool to speed up the polymerization. Combining ultrasonic and ammonium persulfate led to a higher conversion and higher rate of polymerization. Ultrasonic energy has an effect on the particle size distribution. The particle size distribution increases with an increase in the monomer conversion of styrene for ultrasonic polymerization, whereas the particle size distribution did not change with an increase in the monomer conversion compared with the conventional thermal polymerization results. Higher molecular weights were obtained under ultrasonic irradiation. FE‐SEM and TEM pictures show different morphology with changing temperature polymerization. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Comparison of the Different Vulcanization Techniques of Styrene Modified Natural Rubber (SNR) as an Impact Modifier of Natural Rubber-Based High Impact Polystyrene (NRHIPS)

Styrene modified natural rubber (SNR) is a modified rubber that can work as an impact modifier and compatibilizer for polystyrene (PS) matrix. The effect of different vulcanization techniques based on the sulfur vulcanization system has been investigated to produce SNR vulcanizates for natural rubber-based (NR) impact modifier for polystyrene. SNR is produced through emulsion polymerization of styrene monomer and deproteinized natural rubber (DPNR) latex. The styrene to DPNR ratio is 25:75 (wt/wt). SNR is vulcanized using sulfur vulcanization system with 1.5 phr sulfur loading for each blend. Each PS/SNR blend contains 20% rubber. Three different vulcanization techniques are proposed to produce SNR vulcanizates: mixed system ( in situ mixing together with physical mixing using two roll mills), in situ vulcanization, and physical mixing using two roll mills. PS/SNR blends show the in situ vulcanization process produce SNR vulcanizate, which gives the blends with better tensile properties and impact strength compared with the mixed system and physical mixing. The morphology in PS/SNR blends of PS/R1, PS/R2 and PS/R3 have further prove that SNR has better interaction with PS matrix compared with PS/*DPNR. PS/R3, which because they have in situ vulcanization SNR vulcanizate prepared by latex-based formulation, successfully produce SNR vulcanizates that can contribute as a natural rubber-based impact modifier.

One-pot synthesis of organo-functionalized monodisperse silica particles in W/O microemulsion and the effect of functional groups on addition into polystyrene

The direct synthesis from TEOS and organosilanes is carried out in W/O microemulsion in order to prepare monodisperse functionalized silica nanoparticles. The well monodisperse particles are obtained successfully from a wide range of concentration of 3-aminopropyltriethoxysilane (APTES), 3-mercaptopropyltrimethoxysilane (MPTMS), phenyltrimethoxysilane (PTMS), vinyltriethoxysilane (VTES) and 3-cyanoethyltriethoxysilane (CETES) in the solution of TEOS and polyoxyethylene nonylphenol ether (NP-5). The particle size can be controlled without widening the distributions. On the other hand, the direct synthesis with these organosilanes and TEOS by conventional Stöber method using no surfactant provides colloidal solutions with DLS plots with wide or bimodal dispersions. NP-5 is removed by washing the colloids with DEGDEE and the decline of IR absorptions due to the benzene ring stretching is observed. The resultant colloidal powder is occluded into polystyrene by the polymerization of styrene monomer in the presence of these functionalized silica nanoparticles. The heat resistance of modified polystyrene is investigated by TG–DTA in dry air. The position of DTA peak due to combustion of the polymer is shifted to a higher temperature with the addition of silica nanoparticles. The considerably large shift is found in silica nanoparticles prepared with VTES and PTMS, whose difference is higher than that by the addition of simple silica nanoparticle with no functional groups.

Immobilization of RAFT agents on silica nanoparticles utilizing an alternative functional group and subsequent surface‐initiated RAFT polymerization

AbstractSilica–polystyrene core‐shell particles were successfully prepared by surface‐mediated reversible addition fragmentation chain transfer (RAFT) polymerization of styrene monomer from the surfaces of the silica‐supported RAFT agents. Initially, macro‐RAFT agents were synthesized by RAFT polymerization of γ‐methacryloxypropyltrimethoxysilane (MPS) in the presence of chain transfer agents (CTAs). Immobilization of CTAs onto the silica surfaces was then performed by reacting silica with macro‐RAFT agents via a silane coupling. Grafting of polymer onto silica forms core‐shell nanostructures and shows a sharp contrast between silica core and polymer shell in the phase composition. The thickness of grafted‐polymer shell and the diameter of core‐shell particles increase with the increasing ratio of monomer to silica. A control experiment was carried out by conventional free radical emulsion copolymerization of MPS‐grafted silica and styrene under comparable conditions. The resulting data provide further insight into the chemical composition of grafted‐polymers that are grown from the silica surface through RAFT process. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 467–484, 2009

Preparation and Characterization of Au Nanoparticles/Polymer Composite Photonic Crystals

We report a simple approach to prepare An/polystyrene (PS) composite photonic crystals. In this approach, Au nanoparticles protected by thiol molecules were synthesized by two-phase system using dimethylamine-boran as reducing agent at low temperature. PS microstructures containing the obtained Au nanoparticles were prepared by polymerization of styrene monomer in the presence of Au nanoparticles using a silica inverse opal as template. The composites with different Au content were prepared, and their structural and optical characteristics were characterized by transmission electron microscopy (TEM) and optical absorption spectroscopy, respectively. The relationship between microstructures including particle size and volume fraction of metal phase, and optical properties has been systematically evaluated. These characterization indicate that reflection peak of the obtained composite can be controlled by the volume fraction of Au nanoparticles.

Polymerization as a means of stabilization for polystyrene

AbstractGeneral purpose polystyrene prepared by conventional radical techniques contains a head‐to‐head unit as a consequence of polymerization termination by radical coupling. As has been previously demonstrated, thermal stress promotes homolysis of the bond linking the head‐to‐head components. The macroradicals that were generated depolymerize rapidly to generate styrene monomer. This decomposition during processing can lead to finished articles containing objectionable levels of styrene monomer, particularly for food packaging applications in which even low levels of monomer can promote objectionable taste and aroma. Polymer containing no head‐to‐head units should not be prone to this facile decomposition. In this instance, polystyrene has been prepared by nitroxyl‐mediated polymerization of styrene monomer followed by reductive removal of nitroxyl end groups. Polymer prepared in this manner contains no head‐to‐head units and displays thermal stability much greater than that observed for conventional polystyrene. A direct comparison of the stability for the two polymers is readily available by thermogravimetric techniques. A quantitative reflection of the difference in stability is available from the rate constants for the respective decompositions. decompositions. J. VINYL ADDIT. TECHNOL., 12:198–203, 2006. © 2006 Society of Plastics Engineers

Super-polystyrene: a new class of engineering plastics with versatile properties

Many attempts to upgrade polystyrene have been made in the past. One of the last and most popular examples is the upgrading of polystyrene by stereo-controlled polymerization of styrene monomer, yielding a syndiotactic material. But the property profile of polystyrene can also be improved by stiffening the polymer chain with bulky groups. 1,1-Diphenylethylene (DPE) was selected as a monomer with such a bulky group and was copolymerized anionically with styrene to give an amorphous copolymer with a statistical chain structure which was called 'super-polystyrene'. In this paper the conditions of the anionic polymerization and the properties of the resulting materials are described. Depending on the DPE content, the glass transition temperature can be varied from 104°C to 180°C. Up to a DPE content of 15%, these styrene-DPE copolymers are miscible with GPPS as well as with syndiotactic polystyrene. Toughening of the transparent polymers was achieved with glass fibers and grafted rubber particles. Block copolymerization with minor amounts of butadiene yielded a tough and transparent polymer. Thermoplastic elastomers with an enhanced softening point having the block sequence S/DPE-b-Bu-b-S/DPE and S/DPE-b-EB-b-S/DPE were also prepared.

Synthesis of IPN Polymer Hybrids by In-Situ Radical Polymerization Method and Their High Resistivity to Solvent Extraction

Abstract Two different types of polymer hybrids having an interpenetrating polymer network (IPN) of the organic gel and silica gel were prepared by the in-situ polymerization method. One type is the IPN polymer hybrids of poly(N,N′-dimethylacrylamide) gel and silica gel that were prepared by simultaneous polymerization of N,N′-dimethylacrylamide and N,N′-methylenebisacrylamide in a methanol solution of tetramethoxysilane (TMOS). The other type is IPN polymer hybrids of polystyrene gel and silica gel that were prepared by the polymerization of styrene monomer in the presence of divinylbenzene and TMOS. Radical polymerization of these organic monomers proceeded effectively in the sol-gel reaction mixture of TMOS, resulting in homogeneous glassy materials. The formation of IPN structure was confirmed by the solvent extraction. The loss of organic elements could be prevented in both cases by the incorporation of cross-linking points in the organic network. The homogeneity of these IPN polymer hybrids were supported by nitrogen porosimetry measurements. The results demonstrated that the porous silicas obtained from the polymer hybrids had high surface areas and large pore volumes and exhibited a sharp distribution of pore size below 2 nm in both types of IPN polymer hybrids. These results indicate a molecular-level integration of the organic gel and silica gel in the IPN polymer hybrids.

Imaging, polymerization, and reconstruction of polystyrene films with a scanning tunneling microscope

Polystyrene microparticles can be investigated by using a scanning tunneling microscope. The observed images show the hydrogen atoms on the phenyl groups and the extended polymer chains without entanglement. After a sustained tip scanning, some of the polystyrene surfaces develop a highly ordered structure. Furthermore, the polymerization of styrene monomers can be initiated by the tip field, to form nanometer-scale polystyrene films on graphite substrates, in air at room temperature. The yield was verified by time-of-flight secondary ion-mass spectroscopy.