Methyl Styrene Research Articles

SK buys Deltech aromatics businesses

The venture capital firm SK Capital has acquired a controlling interest in the monomer, polymer, and European businesses of Baton Rouge, Louisiana–based Deltech. The businesses employ 135 people making specialty aromatic monomers such as vinyl toluene, divinyl benzene, and p -methylstyrene. They also make crystal polystyrene for high-end applications such as cosmetics packaging. Deltech CEO Bob Elefante is retaining a minority stake and will remain active in the businesses, SK says.

Superior Properties through Feedstock Development for Vat Photopolymerization Additive Manufacturing of High-Performance Biobased Feedstocks.

Vat photopolymerization additive manufacturing (Vat AM) technologies have found niche industrial use being able to produce personalized parts in moderate quantity. However, Vat AM lacks in its ability to produce parts of satisfactory thermal and mechanical properties for structural applications. The purpose of this investigation was to develop high-performance resins with glass transition temperatures (Tg) above 200 °C for Vat AM, evaluate the properties of the produced thermosets and establish a structure–property relationship of the thermosets produced. Herein, we have developed SLA-type resins that feature bio-derived monomer hesperetin trimethacrylate (HTM) synthesized from the flavonone hesperetin. Diluents 4-acryloyl morpholine, styrene, 4-methyl styrene and 4-tert butylstyrene (tbutylsty) were photocured with HTM as the monomer and all produced thermosets with Tg values above 200 °C. Investigations of suitable crosslinkers urethane dimethacrylate, the vinyl ester CN 151 and Ebecryl 4859 (Eb4859) showed that each crosslinker displayed different benefits when formulated with HTM as the monomer and tbutylSty as the diluent (HTM:crosslinker:tbutylSty with mass ratio 2:1:2). The crosslinker CN 151 produced the thermoset of greatest onset of thermal decomposition temperature (T0) of 352 °C. Eb4859 produced the thermoset of highest tensile strength, 19 ± 7 MPa, amongst the set of varied crosslinkers. The formulation featuring UDM (HTM:UDM:tbutysty) offered ease of processing and was seemingly the easiest to print. Investigations of reactive diluent showed that styrene produced the thermoset of the highest extent of cure and the overall highest tensile strength, 25 ± 5 MPa, while tbutylSty produced the thermoset with the greatest Tan-δ Tg, 231 °C. HTM was synthesized, formulated with diluents, crosslinkers and initiators. The HTM resins were then 3D printed to produce thermosets of Tg values greater than 200 °C. The polymer properties were evaluated and a structure–reactivity relationship was discussed.

Image quality evaluation of projection- and depth dose-based approaches to integrating proton radiography using a monolithic scintillator detector

The purpose of this study is to compare the image quality of an integrating proton radiography (PR) system, composed of a monolithic scintillator and two digital cameras, using integral lateral-dose and integral depth-dose image reconstruction techniques. Monte Carlo simulations were used to obtain the energy deposition in a 3D monolithic scintillator detector (30 × 30 × 30 cm3 poly vinyl toluene organic scintillator) to create radiographs of various phantoms—a slanted aluminum cube for spatial resolution analysis and a Las Vegas phantom for contrast analysis. The light emission of the scintillator was corrected using Birks scintillation model. We compared two integrating PR methods and the expected results from an idealized proton tracking radiography system. Four different image reconstruction methods were utilized in this study: integral scintillation light projected from the beams-eye view, depth-dose based reconstruction methods both with and without optimization, and single particle tracking PR was used for reference data. Results showed that heterogeneity artifact due to medium-interface mismatch was identified from the Las Vegas phantom simulated in air. Spatial resolution was found to be highest for single-event reconstruction. Contrast levels, ranked from best to worst, were found to correspond to particle tracking, optimized depth-dose, depth-dose, and projection-based image reconstructions. The image quality of a monolithic scintillator integrating PR system was sufficient to warrant further exploration. These results show promise for potential clinical use as radiographic techniques for visualizing internal patient anatomy during proton radiotherapy.

Effect of styrene acrylonitrile copolymer on the performance of TEP/PMMA composites

In this paper, TEP/PMMA composites system and SAN/TEP/PMMA composites system were prepared by in situ polymerization using methyl methacrylate (MMA), triethyl phosphate (TEP) and styrene acrylonitrile copolymer (SAN) as raw materials. The results show that TEP can improve the flame retardant performance of PMMA, and the oxygen index increases from 18.35% to 23.75%, when the content of TEP reaches 20 wt%, UL-94 reaches the V-0 level, but its thermal and mechanical properties are affected by ester group in TEP, which decreases significantly with the increase of TEP content; the mechanical and thermal properties of the composites system are improved with the increase of SAN content and tensile strength. The tensile strength increased from 37.06 MPa to 45.5 MPa, the bending strength increased from 44.58 MPa to 55.01 MPa, and the shore hardness increased from 80HD to 82HD. SAN/TEP/PMMA composites system can improve the initial decomposition temperature and increase 16 °C, the flame retardant performance of SAN/TEP/PMMA composites system is not affected by SAN content, and the visible light transmittance of both TEP/PMMA and SAN/TEP/PMMA composites system can reach 88%. This research will be of great significance in many fields such as architecture, automobile, home decoration, advertising and so on.

Synthesis and characterization of high-temperature self-crosslinking polymer latexes and their application in water-based drilling fluid

Self-crosslinking soap-free latexes (PMS) were synthesized by semi-continuous polymerization from methyl methacrylate and styrene with N-(hydroxymethyl)acrylamide (NAM) as high-temperature self-crosslinker and 2-acrylamido-2-methyl-1-propanesulfonic acid as reactive emulsifier. All PMS latexes with varying NAM contents (0–7 wt%) processed high solid contents (~30%) and monodispersed nano-micro particle sizes (180–600 nm). With augment of NAM content, monomer conversion slightly decreased while particle size decreased and then gradually increased, accompanied with increase of coagulum content. The self-crosslinking behavior showed highly dependence on NAM content and temperature, and the self-crosslinked structures were confirmed by FT-IR, XPS, DSC and SEM. The self-crosslinking latexes effectively improved rheological and microporous filtration properties of bentonite-based drilling fluid. Owing to stronger interparticle interactions, the latexes exhibited better viscosity-increasing effect after thermal treatment and stronger fluid-loss-reducing ability at high temperature. The microporous plugging mechanism was revealed to be the combination of heat deforming and self-crosslinking film forming besides physical bridging and filling.

Photoenzymatic RAFT Emulsion Polymerization with Oxygen Tolerance

Photoenzymatic reversible addition-fragmenatation chain transfer (RAFT) emulsion polymerization, surfactant-free or ab initio, of various monomers is reported with oxygen tolerance. In surfactant-free emulsion polymerizatoin, poly(N, N-dimethylacrylamide)s were used as stabilizer blocks for emulsion polymerization of methyl acrylate, n-butyl acrylate and styrene, producing well-defined amphiphilic block copolymers, including those with an ultrahigh molecular weight, at quantitative conversions. The controlled character of surfactant-free emulsion polymerization was confirmed by kinetic studies, chain extension studies and GPC analyses. Temporal control was demonstrated by light ON/OFF experiments. In ab initio emulsion polymerization of methyl acrylate and methyl methacrylate, low-dispersity hydrophobic polymers were synthesized with predictable molecular weights. This study extends the monomer scope suitable for photoenzymatic RAFT polymerization from hydrophilic to hydrophobic monomers and demonstrates that oxygen-tolerance can be equally achieved for emulsion polymerization with excellent RAFT control.

Additive-free aerobic C-H oxidation through a defect-engineered Ce-MOF catalytic system

Ce-UiO-66 MOF, namely cerium-organic framework was prepared through a fast and efficient method under ultrasonic radiation. After preparation, it was identified using some different microscopic and spectroscopic techniques such as PXRD, FT-IR, TG/DTA, BET, BJH, and FE-SEM. The catalytic activity of Ce-UiO-66 MOF was checked in aerobic oxidation of methyl arenas, alcohols and styrene derivatives in a sustainable circumstance with no additives. Moreover, its catalytic activity was surveyed influenced by a number of variables in the ultrasonic synthesis method. Some parameters such as solvent, base, temperature, amount of the catalyst and time were also tested to optimize the aerobic oxidation reaction. After the 10th run, the recycled Ce-MOF showed an acceptable efficiency, which proved its high reusability and stability under optimized conditions. Furthermore, the Ce-UiO-66 was investigated structurally by PXRD method which demonstrated the catalyst stability after the aerobic oxidation reaction. • Aerobic oxidation of methyl arenes, alcohols, and styrene derivatives. • Simple and efficient synthesis method for defect-engineered Ce-MOF preparation. • Using a non-precious metal catalyst for the aerobic oxidation process. • Air as a green oxidant for the oxidation process. • Using inert solvents to increase oxygen solubility and efficiency.

Effectiveness of Copolymer of Polymethylmethacrylate and Styrene as a Plugging Agent in Water-Based Drilling Fluids

In the development of shale gas, it is important to ensure the stability of the borehole wall. The stability of the borehole wall depends on the plugging ability of the drilling fluid, while the stabilizing ability of the drilling fluid is provided by adding the plugging agent to the fluid. Conventional plugging agents are characterized by a relatively high volume and do not allow one to effectively plug micropores and microcracks in shale rock. In this work, the PMMA-St copolymer was synthesized by emulsion polymerization of methyl methacrylate and styrene. The characteristics of the PMMA-St copolymer were studied by FT-IR, TGA, and phase analysis optical scanning methods. The results show that the size of PMMA-St nanoparticles ranges from 34 to 58 nm, and the average diameter is about 40.6 nm. The decomposition temperature of PMMA-St nanoparticles is 374.8°C, which indicates the good thermal stability of the copolymer. The PMMA-St nanoparticles have little affect on the rheological properties of water-based drilling fluids. The mud cake simulation method was used to evaluate the plugging performance of PMMA-St nanoparticles. The permeability of mud cake is 2.24 × 10-5 m2, which is close to the permeability of shale formation. When 0.5 wt % of the PMMA-St copolymer is added to the solution, the blocking rate is 70.27%. With increase in PMMA-St concentration, the blocking rate of the mud cake increases. The best stabilizing effect is achieved when the PMMA-St copolymer concentration is 1.0%. The results of the core experiments are consistent with the mud cake simulation, which indicates the excellent sealing ability of the PMMA-St copolymer. Therefore, PMMA-St nanoparticles can be effectively used as a plugging agent to ensure borehole stability in the shale formation.

Synthesis, properties and graft polymerization of ionic conjugated polymers with TCNQ anion radical

The reactions of N-(2,4-dinitrophenyl)pyridinium 7,7′,8,8′-tetracyanoquinodimethane anion radical (TCNQ−.), namely, salt(TCNQ−.), with piperazine and 2-methylpiperazines without catalyst addition resulted in the opening of pyridinium ring to yield ionic polymers with 5-piperazinium-2,4-dienylideneammonium (PDA) TCNQ−. and 2-methylpiperazinium-2,4-dienylideneammonium (MPDA) TCNQ−. units, respectively, namely polymer(R;TCNQ−.) (R = H, Me, (R)-(−)-Me, and (S)-(+)-Me). The polymerization of methyl methacrylate (MMA) and styrene (St) initiated by AIBN, followed by the treatment with polymer(R;TCNQ−.) afforded radical coupling between TCNQ−. and the terminal radical of growing PMMA and PSt, resulting in poly(PDA) and poly(MPDA) with the PMMA and PSt graft chains, i.e., polymer(R;TCNQ−;GC) (GC = graft chain; PMMA and PSt). The 1H NMR, UV–vis, and SEM data suggested that the structures of polymer(R;TCNQ−;GC) in solution depended on solvent polarity. The electrochemical, magnetic, optical, and thermal properties of the polymers were also investigated.

Base-Promoted Tandem Synthesis of 2-Azaaryl Tetrahydroquinolines.

A novel method to synthesize 2-azaaryl tetrahydroquinolines by the base-promoted tandem reaction of azaaryl methyl amines and styrene derivatives is reported (over 30 examples, yields up to 95%). Mechanistic probe experiments demonstrate that the deprotonation of the benzylic C-H bond and the addition to the styrene vinyl group proceeds via the SNAr mechanism.

비닐톨루엔의 연소특성치의 측정 및 예측

The combustion property is one of the important safety specification use to characterize the hazard potentials of a chemical material. Therefore, the accuracy information of thecombustion characteristics of hazardous substances is very important in developing appropriate the accident prevention and the protection in chemical industries. Most of combustible substances are the ones for which the discrepancy was noted between the experiment and the literature data of fire and explosion properties. This work measures the lower/upper flash points, fire points and autoignition temperature of vinyltoluene(VT), which is mainly used as a solvent and chemical intermediate in various applications including polyester resins, modifiers, heat-resistant strengthening agents, adhesives, and paper coatings. The lower/upper flash points of vinyltoluene by using Setaflash closed-cup were experimented at 47 ℃ and 102 ℃, respectively. The Pensky-Martens tester(CC) was experimented at 49 ℃. The flash points of vinyltoluene by the Tag and Cleveland open cup testers were experimented at 63 ℃ and 54 ℃, respectively. The AIT of vinyltoluene was experimented at 466 ℃. The LEL(lower explosion limit) and the UEL(upper explosion limit) by using Setaflash lower/upper flash point values were calculated as 0.86 vol% and 11.45 vol%, respectively.

A polythiophene/UiO-66 composite coating for extraction of volatile organic compounds migrated from ion-exchange resins prior to their determination by gas chromatography

A Poly (3,4-ethylenedioxothiophene) (PEDOT)/UiO-66 composite was electrodeposited on an etched stainless-steel wire as head-space solid-phase microextraction (HS-SPME) coating. A robust, well controlled thickness, and uniform coating of metal organic framework composites can be realized by the electrodeposited strategy. The incorporated UiO-66 not only enhanced the uniformity and stability of the composite coating, but also effectively decreased the stacking phenomenon of PEDOT and improved its extraction efficiency, which was over 100 times higher than that of the PEDOT coating without UiO-66. The composite coating was used to enrich seven types of volatile organic compounds (VOCs) in ion-exchange resins, including methyl cyclohexane, benzene, toluene, ortho-xylene, styrene, para-xylene and divinyl-benzene. The results of adsorption isotherm analysis showed that π stacking effect played dominant role between the composite coating and VOCs in the extraction process. The composite coating was characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared and thermogravimetric analysis, respectively. A determination method for seven kinds of VOCs was established by HS-SPME coupled with gas chromatography-flame ionization detection (GC-FID). Under the optimal experimental conditions, the detection linear range (LRs) was 0.09-100 ng mL−1, and the detection limit (LODs) was 0.03-0.06 ng mL−1 (S/N = 3). The method was applied for the migration detection of VOCs in four types of ion-exchange resin, which showed satisfactory recovery (84.5-117.2%).

Study on preparation and process of poly(MMA‐St) thermally expandablecore‐shellmicrospheres

AbstractThermally expandable microspheres were synthesized by the suspension polymerization of methyl methacrylate (MMA) and styrene (St) in the presence of paraffin blowing agents. The effect of the monomer composition, the initiator, the blowing agent, the polymerization temperature on the morphology and structure of microspheres were studied. The results showed that AIBN initiated the water phase polymerization of MMA to form secondary polymer particles adsorbed on the surface of the microspheres. MMA diffused from the oil phase to the water phase, which accelerated the phase separation and facilitated the formation of core‐shell microspheres. However, LPO could not initiate the water phase polymerization, the phase separation was slow and there was an intermediate state with a porous surface. When the boiling point of the blowing agent was lower than the polymerization temperature, the microspheres were porous and there were a large number of holes on the surface.

Methyl methacrylate-styrene copolymers prepared by utilizing the Trommsdorff effect in an inverted two-stage extruder

In this work, the influence of initial viscosity on the Trommsdorff effect was firstly investigated, and it was confirmed that 1000 ± 100 Pa · s of viscosity could be a criterion of the Trommsdorff effect. On this basis, a new inverted two-stage extruder was established, the designed ‘blocking unit’ was introduced to the screw configuration, and then the continuous bulk copolymerization of methyl methacrylate (MMA) and styrene (St) was carried out. The results showed that the blocking unit could effectively enhance the residence time of copolymerization, and make the molecular weight distribution of copolymer more uniform. The position of the Trommsdorff effect in the extruder was then determined by the thermal effect of copolymerization, and the mixed monomers were continuously added to effectively utilize the Trommsdorff effect. As a result, the MMA-St copolymers with high molecular weight and narrow distribution were prepared via reactive extrusion, which possessed higher melt flow rate and better thermal stability than pure-PMMA. The present work provides important reference and guidance for the industrialization of bulk free radical copolymerization via reactive extrusion.

Electrochemical Hydrogenation of Alpha Methyl Styrene to Cumene

Electrochemical Hydrogenation of Alpha Methyl Styrene to Cumene

Comparison of fire resistance of polymers in intumescent coatings for steel structures

Thermal destruction of fire-retardant intumescent coating of the composition of ammonium polyphosphate (APP)/melamine (MA)/pentaerythrite (PE)/titanium oxide (TiO 2 )/polymer, which can be applied for fire protection of steel structures, was studied. The influence of polymers of different nature – ethylene-vinyl acetate (EVA), vinyl acetate versatate (VAVV), styrene acrylates, and vinyl toluene acrylate on the processes of formation of a coke layer and fire-retardant effectiveness of appropriate coatings was determined. Chemical transformations of polymers EVA and styrene acrylate in the intumescent system of ARR/MA/PE/TiO 2 in the temperature range of 200–800 °С were studied. It was established that the processes of the thermal destruction of vinyl acetate polymer are more harmonized with chemical reactions of the components of the intumescent system than similar processes for acrylate aromatic polymers. Thermal-oxidation destruction of intumescent compositions at the temperatures of 200–800 °С was explored. It was shown that basic chemical processes with polymers of EVA and VAVV begin after 300 °С and flow in the temperature range of 350–600 °С. It was found that the noticeable degradation of the carbon-phosphorus frame of intumescent compositions with styrene acrylate polymers begins at 450 °С, which is almost by 150 °С below the temperature of degradation of the compositions containing vinyl acetate binders. The conducted fire tests demonstrate that intumescent compositions with the use of acrylate aromatic polymers are more effective at the low coating thickness in ensuring the fire resistance boundary of 30 min. In order to ensure higher values of fire resistance, it is necessary to use intumescent coatings containing vinyl acetate co-polymers as the polymer component. The study of the impact of polymers of intumescent coatings on the boundary of fire resistance of steel structures has scientific and practical significance for the development of differentiated fire protection means, oriented to the given class of fire resistance. Fire-retardant intumescent compositions examined in this study can be used as the basis for the formulations of materials for fire protection of building structures under conditions of a standard fire

Radical Lifetimes in Atom Transfer Radical Polymerization: A Monte Carlo and Deterministic Investigation

Mean radical lifetimes and fluctuations in lifetime are shown to decrease with conversion and polydispersity index for atom transfer radical polymerization (ATRP) of both methyl methacrylate and styrene. In the first study of its kind, a comprehensive investigation of radical lifetimes in both ATRP and conventional free-radical polymerizations is reported using a kinetic Monte Carlo model. Quantile–quantile plots show the radical lifetimes to be exponentially distributed with equal mean and standard deviation. Radical lifetimes are shown to be thousands of times longer in conventional free-radical polymerization compared with ATRP. Reduced mean radical lifetimes and fluctuations offer a new perspective on the ATRP mechanism. Reduction in radical lifetime fluctuations ensures less variability in the number of monomer units added during the propagation steps and keeps the polydispersity index low. Deterministic models are used along with the kinetic Monte Carlo model to investigate several facets of these polymerization systems and are validated against experimental data.

Polymer side-chain modification in methacrylate and styrene copolymers through thiol-thioester dynamic exchange

In this paper a methacrylic derivative of naphthalene-2-thiol – S-naphthalene-2-yl 2-methylprop-2-enethioate (2-NAF-S-Met) was synthesized and then copolymerized with two monomers of industrial significance, i.e. methyl methacrylate (MMA) and styrene (ST). The thermal properties of the copolymers were investigated by differential scanning calorimetry (DSC) and thermogravimetry (TG/DTG). Also, Shore hardness tests of the obtained polymers and optical properties (transparency) were assessed. By replacing the thioester-linked substituent components of the side chains in the thioester-derived polymers through the thiol-thioester exchange reactions, a facile control over the polymer properties (hardness, Mn and Mw, transparency, stability, solubility, etc.) was demonstrated. The molar masses (Mn) of new materials after thiol-thioester exchange using 2-mercaptoethanol were reduced to 6.85 × 104 Da (for ST copolymers) and to 1.22 × 106 Da (for MMA copolymers), respectively. Second exchange sequence with thiophenol resulted in an increase in the molar mass of these products. The replacement of substituents also caused an improvement in thermal stability, especially for MMA copolymers, as well as a decrease of the glass transition temperatures.

Cross-Linked Polythiomethacrylate Esters Based on Naphthalene-Synthesis, Properties and Reprocessing.

Two structurally different aromatic dithioesters were synthesized from two dithiols and methacryloyl chloride. The polymer networks based on methyl methacrylate and/or styrene and the new dimethacrylates were subsequently prepared. The polymerization yields of copolymers were in the range of 95–99%. The thermal and mechanical properties of the copolymers were determined by means of differential scanning calorimetry (DSC), thermogravimetric analysis (TG/DTG), and Shore D hardness. The addition of dithioesters—1,5-NAF-S-Met (or 1,4(1,5)-NAF-CH2S-Met) (from 0.5% to 5%) to MMA- or ST-based polymers results in lowering the glass transition temperature (Tg) by about 8 °C. The thioester-containing polymers based on MMA exhibit lower thermal stability than those with ST. The polythioesters are stable up to 250 °C. The UV/vis spectra and refractive indexes of prepared liquid compositions were also measured. The 1,5-NAF-S-Met (and 1,4(1,5)-NAF-CH2S-Met) improved the refractive index values of ST and MMA compositions. The double bond conversion was also determined for all synthesized materials. The swelling studies of polymers with 20% addition of thioester crosslinkers were investigated. For all polymeric materials with 20% addition of thioesters, depolymerization of the network was carried out by thiol-thioester exchange. The depolymerization products were re-reacted in a thiol-ene reaction with 2-hydroxyethyl methacrylate by thermal initiation. The thiol-ene procedure enabled reprocessing of starting polymers and obtaining new materials characterized by distinctly different thermal, mechanical, and swelling properties. The thiol-ene materials exhibit a lower Shore hardness in the range of 20–50 °Sh, as well as decreased Tg values when compared to starting copolymers. Due to these possible exchange reactions, one can facilely manipulate the properties of the polymers which could lead to the manufacturing of the new products with the desired features. Degradation of the cross-linked structure and recycling of copolymers were also discussed.

Polysiloxane Scintillators for Efficient Neutron and Gamma-Ray Pulse Shape Discrimination

Plastic scintillators based on thermoplastics, such as polystyrene and poly(vinyl toluene) (PVT), are capable of neutron and γ radiation detection via pulse shape discrimination (PSD) when overdope...