Emulsion Polymerization Of Styrene Research Articles

Investigation of an ambient temperature-curable soy-based adhesive for wood composites

Soy-based bio-adhesives are considered as potential substitutes for formaldehyde-based wood adhesives due to their environmental safety and broad availability. However, high curing temperatures (120–180 °C) makes them less energy efficient for wood processing. In the present study, an ambient temperature-curable soy-based adhesive was prepared via the emulsion polymerization of soy flour and styrene. The results of Fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1HNMR) confirmed that N-methylolacrylamide had grafted onto the soy flour components, and subsequently copolymerized with styrene. The developed soy-based adhesive achieved a wet shear strength of 1.04 MPa with 5% styrene and 8% pMDI, which exceeded the bonding strength requirements of plywood for exterior applications. Soy flour components are essential for this ambient temperature-curable adhesive system. The emulsion soy-based adhesive facilitates moisture evaporation at ambient temperature, and polymeric methylenediphenyl diisocyanate (pMDI) was introduced to produce a crosslinked structure with high water resistance and thermal stability. The soy-based adhesive developed in this study showed great potential in wood composites thanks to its high performance and low curing temperature.

Significantly Suppressed Chain Transfer to Monomer Reactions in RAFT Emulsion Polymerization of Styrene

The highest accessible molecular weight of the living product in controlled/living radical polymerizations (CLRPs) is determined by the constant of chain transfer to monomer reaction. Thus, the highest molecular weight of living polystyrene had been believed around 100 kg/mol in CLRPs. In our previous report (Yan, K.; Gao, X.; Luo, Y. Well-Defined High Molecular Weight Polystyrene with High Rates and High Livingness Synthesized via Two-Stage RAFT Emulsion Polymerization. Macromol. Rapid Commun. 2015, 36 (13), 1277–1282), we surprisingly found that the livingness of polystyrene of 550 kg/mol could be up to 90% in RAFT emulsion polymerization. Herein, we experimentally measure the constant of chain transfer to monomer reaction in RAFT emulsion polymerization of styrene at various temperatures from 60–80 °C. Very interestingly, it is found that the constant of chain transfer to monomer reaction should be only about one-third of that of the corresponding conventional radical polymerization. From the derived A...

Controllable synthesis of monodisperse nonspherical colloidal particles with cavity structures

ABSTRACTThis article reports a facile controllable approach to prepare monodisperse nonspherical colloidal particles with cavity structures by one‐pot soap‐free emulsion polymerization of styrene (St), 3‐(trimethoxysilyl)propyl methacrylate (MPS), and acrylic acid (AA). In our strategy, only by varying the feeding time of AA to the as‐polymerized St and MPS, the nonspherical latex particles with single cavity of different surface roughness and multicavity structures could be successfully synthesized. The depth and width of the cavity can be also easily controlled by adjusting the amount of MPS and AA. A possible formation mechanism is proposed on the basis of experimental results. These nonspherical colloidal particles, which have controllable cavity structures, are good building blocks or templates for the construction of functional coating and complex colloidal architectures. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1645–1652

Polymerizable dye for colored particles synthesis with potential use in immunoassays

Latex-particles are suitable for diagnosis purpose since they are able to interact with biological molecules. In this work, a colored monomer was synthesized between basic fuchsine(BF) and glycidyl methacrylate(GMA). BF-GMA obtaining was verified through UV-Vis, IR, NMR and Mass spectrometry. The synthesis of colored particles by emulsion polymerization of styrene and the BF-GMA monomer was studied by measuring conversion, particle diameter, BF incorporation, surface charge densities and also in a protein binding assay. Results confirmed the production of stable particles, with controlled size and high BF incorporation, capable of interacting with proteins efficiently, and being used in an immunoagglutination test.

Synthesis of 9-octadecenoic acid grafted graphene modified with polystyrene for efficient light oil removal from water

This paper presents a novel hydrophobic material based 9-octadecenoic acid grafted graphene (POG) for oil/water separation. Graphene derived from graphite was modified with 9-octadecenoic acid to obtain 9-octadecenoic acid grafted graphene (OG). Then, emulsion polymerization of styrene was performed on OG to produce polystyrene branches on 9-octadecenoic acid grafted graphene (POG). Synthesized POG composites were then characterized by using various tools. The separation performance of the composites was evaluated by using an emulsion of organic compounds such as heptane with dye-colored water. Three different composites were prepared by varying the amount of 9-octadecenoic acid grafted graphene used as follows: POG25, POG50, and POG75. The results showed that the higher the ratio of the 9-octadecenoic acid grafted graphene, the higher the oil uptake efficacy of the material and the faster the rate of the adsorption. The material was regenerated and its performance was tested again. The adsorption rate was constant for the next several cycles. Thus, this material has the potential to be utilized to clean up oil spills or to remove oil contaminants from water for cleaner production of produced water.

Catalyst: Size Distribution in Self-Assembly Matters

Dafni Moatsou completed her PhD in chemistry at the University of Warwick in 2015, was a Marie Sklodowska-Curie fellow at the Adolphe Merkle Institute until 2017, and is a junior research group leader at the Karlsruhe Institute of Technology, where she focuses on sequence control and self-assembly of polymers. Rachel O’Reilly completed her PhD in 2003 at Imperial College London. She currently holds a chair in chemistry within the College of Engineering and Physical Sciences at the University of Birmingham. In August 2018 she became the head of the School of Chemistry. Her research targets the design, synthesis, and application of polymeric materials, where control over architecture, functionality, and reactivity are central to their application.

Core-Crosslinked Nanoparticles from Amphiphilic Poly (Ethylene Oxide) Macro-RAFT Agent and Styrene: Preparation and Characterization

An unseeded surfactant-free styrene emulsion polymerization is employed to prepare core-crosslinked particles with poly (ethylene oxide) monomethyl ether (mPEO) macro-revesible addition fragmentation chain transfer (RAFT) agent as both the stabilizer and the control agent. The pegylated amphiphilic macro-RAFT agent (mPEO5000-TTC) was synthesized via coupling poly(ethylene oxide) monomethyl ether with a hydrophobic dodecyl trithiocarbonate chain and utilized to form the micelles and control the polymerization and crosslinking of styrene in aqueous solution. The FTIR, 1H NMR, TEM (transmission electron microscopy), dynamic light scattering (DLS) were used to clarify the structure and morphology of nanoparticle. The thermal performance of nanoparticles was measured by TGA (thermogravimetric analysis). The results showed that with the increasing of concentration monomer, the produced size of particles enlarged and then tended to be maximum, while the thermal stability was decreased comparative to the mPEO precursor. The thermal stability of crosslinked particles reflected lower than that of uncrosslinked, which is elucidated with formation and collapse of micelles and micro-phase separation.

Hollow Mesoporous Organic Polymeric Nanobowls and Nanospheres: Shell Thickness and Mesopore-Dependent Catalytic Performance in Sulfonation, Immobilization of Organocatalyst, and Enantioselective Organocascade

Heterogeneous asymmetric multicomponent/multicatalytic organocascade faces the enormous challenges of tedious immobilization of catalysts, mass transfer, and stereoselective control. In this paper, the mesopore-abundant and well-shaped hollow mesoporous organic polymers, nanobowls (HMOPBs) and nanospheres (HMOPSs), are fabricated via emulsion polymerization of styrene on a polystyrene (PS) core and then removal of PS, accompanied by the adsorption of Co2+ ions, transformation of Co2+ into Co(OH)2, and final removal of Co(OH)2. Among them, the nanobowl HMOPBs(a) with hollow interiors, mesoporous shells, and thin shell thickness (16 nm) possesses the largest surface area (185.7 m2 g–1) and displays the highest reaction kinetics in the sulfonation (2.85 mmol H+ g–1) and then immobilization of 9-amino(9-deoxy)epi-quinine (QNNH2, 1.35 mmol g–1). For the 2,4-substituted bulky reactants in an asymmetric double-Michael cascade, the as-fabricated functional nanobowl can provide a suitable microenvironment to meet ...

Characteristics and Mechanism of Styrene Cationic Polymerization in Aqueous Media Initiated by Cumyl Alcohol/B(C6F5)3

AbstractStyrene cationic polymerizations initiated by cumyl alcohol (CumOH)/B(C6F5)3 are systematically studied in aqueous suspension and emulsion. Theoretical calculations and experimental research suggest that CumOH/B(C6F5)3 has higher initiating activity than H2O/B(C6F5)3. During emulsion polymerization of styrene, molecular weight and polymerization rate decrease with the addition of surfactants. These polymerization processes share the same features. Specifically, all elemental reactions (initiation, propagation, and termination) in aqueous media occur at the droplet interface. End structure analysis indicates that chain transfer reactions to water and a‐proton elimination and chain transfer reactions to monomer occur. The possible mechanism for the styrene cationic polymerization in aqueous media is demonstrated.

Effect of the addition of salt to Pickering emulsion polymerizations using polymeric nanogels as stabilizers

Nanogels made from crosslinked block copolymer micelles are used as stabilizers in the Pickering emulsion polymerization of styrene.

Preparation of composite and hollow particles from self-assembled chitin nanofibers by Pickering emulsion polymerization

This study investigated Pickering emulsion polymerization of styrene using self-assembled chitin nanofibers (CNFs) as stabilizers to produce CNF-based composite particles, which were further converted into hollow particles. Previously, we reported that regeneration from a chitin/1‑allyl‑3‑methylimidazolium bromide ion gel using methanol fabricated self-assembled CNFs. Prior to the emulsion polymerization, CNFs were maleylated by reaction with maleic anhydride in the presence of perchloric acid. After styrene was added to a dispersion of the produced anionic CNFs in ammonia aq., a mixture was ultorasonicated to give an emulsion, in which styrene droplets were stably surrounded by CNFs. Radical polymerization was then conducted in the presence of potassium persulfate as an initiator to produce the composite particles. Particle sizes became smaller as the amounts of CNFs increased. The hollow particles were prepared by solubilizing out the polystyrene cores with toluene.

High Molecular Weight Polystyrene Obtained by Cationic Emulsion Polymerization Catalyzed by Imidazolium‐Based Ionic Liquid

AbstractThe ionic liquid 1‐n‐butyl‐3‐methylimidazolium heptachlorodiferrate (BMI.Fe2Cl7) is efficiently used as catalyst in the cationic emulsion polymerization of styrene. The effect of different reaction temperatures, surfactant, and ionic liquid concentrations on polymer properties as molecular weight distribution and particle size is evaluated. High weight average molecular weights, above 1000 kDa, are achieved at 70% of conversion in 100 nm polystyrene particles formed mainly by micellar nucleation. Particle sizes and molecular weights increase with the decrease of the amount of surfactant. Even at low concentrations, BMI.Fe2Cl7/styrene molar ratio equal to 1/1000, the ionic liquid proves to be efficient for the emulsion polymerization of styrene, and lower ionic liquid concentrations lead to the formation of longer polymer chains.

Synthesis of polystyrene@silica particles through soap-free emulsion polymerization and sol-gel reaction on polymer surfaces

Polystyrene@silica particles were produced through soap-free emulsion polymerization (SFEP) of styrene and N-vinylacetamide (NVA) via the sol-gel reactions of tetraethyl orthosilicate (TEOS) on polymer particle surfaces. Different amounts of NVA were used to prepare polystyrene particles using the SFEP process. The particles covered with poly-NVA then underwent the Stöber process to form an outer silica shell. NVA was found to stabilize the polymer colloids and improve their stability by steric effects, even after the positive charge on the polymer surface was partially neutralized by the electrostatically adsorbed TEOS, which tends to induce particle aggregation. Further, the –NH functional groups on NVA catalyzed the hydrolysis of TEOS in the sol-gel reaction to form silica. Consequently, small, monodisperse, and stable core-shell particles were formed despite having a low zeta potential.

Pickering emulsion polymerization of styrene stabilized by nanocrystalline cellulose

In this work, polystyrene-based oil-in-water Pickering emulsion stabilized by nanocrystalline cellulose (NCC) was formulated. The NCC was prepared by sulfuric-acid-catalyzed hydrolysis of microcrystalline cellulose, with a yield of 60% and an average particle size of about 152.9 nm. When the content of NCC was 5 g/L, the surface tension was 54.58 mN/m, and stable styrene-based Pickering emulsion was prepared using NCC as the stabilizer. The presence of NCC particles in the emulsion system resulted in high resistance against creaming. Due to improved stability, the conversion efficiency of styrene was higher in the polymerization process of the styrene-based Pickering emulsion.

A Comparative Study on Emulsion Polymerization Processes of Styrene Initiated by Water-soluble and Oil-soluble Initiators

The solubility of initiator determines its distribution and the roles played in emulsion polymerization as well as the final products, but this is still lack of systematic investigation. The present work focuses on this issue by comparing the kinetic behaviors and product properties of styrene emulsion polymerization initiated by 2,2-azoisobutyronitrile (AIBN) and potassium persulphate (KPS). Compared to KPS-initiated emulsion polymerization, the AIBN-initiated polymerization was found to be insensitive to the type of emulsifier, and have high polymerization rate as well as narrow molecular weight distribution and particle size distribution. This result indicates the effective free radicals are generated in micelles or colloids, which could decrease the proportion of homogeneous nucleation and make the process and product more controllable. As a consequence, there is a linear relationship between molecular weight of product and AIBN concentration in lg-lg coordinate. It provided a reference for the preparation of latexes with specified molecular weight and supported the possibility of the coexistence of multiple free radicals in one micelle or colloid when using oil-soluble initiator.

Preparation, characterization and mechanism study of small size core-shell polymer nanoparticles dissociated from poly(N-isopropylacrylamide) ionic microgels

Preparation of small size core-shell polymer nanoparticles has significant applications in photonic crystal materials and drug delivery systems. Although core-shell nanoparticles could be easily prepared by seeded emulsion polymerization, their size was generally larger than that of seeds, which limited their further applications in some areas. In this work, a new method was utilized to prepare small size core-shell polymer nanoparticles. In detail, poly(N-isopropylacrylamide) ionic microgels (encoded as PNI microgels) with controllable diameter were firstly prepared and then used as seeds in seeded emulsion polymerization of styrene. After polymerization, core-shell nanoparticles which were smaller in size than that of seeds were obtained. In order to reveal this abnormal phenomenon, the inner structure, components, element distribution, thermo-sensitivity and deformability of the obtained nanoparticles were characterized by TEM, FTIR, DSC, EDS, DLS and AFM. It was found that the core composed of polystyrene and the shell composed of PNI microgels in the core-shell nanoparticles. The detailed formation process was then studied systematically. It was found that polystyrene nanoparticles formed within PNI microgels and peeled off from the seeds when they were large enough. Considering the weak ionic interaction of PNI microgels, mechanism for this phenomenon was proposed. Factors, such as initiator type, microgel type, cross-linking degree and stirring speed, also had significant effects on the formation of core-shell nanoparticles.

Facile fabrication, morphology control, and modification of polymeric yolk–shell microspheres

The fabrication and functionalization of polymeric yolk–shell microspheres (YSMs), possessing a hollow shell and a movable core, is interesting but challenging in materials science. Here we report the facile fabrication, morphology control, and fluorescent modification of polymeric YSMs, which have a spherical core of poly(vinylidene fluoride) (PVDF) and a hollow shell of poly(styrene-co-glycidyl methacrylate). First, flower-like microspheres with core–shell structures are synthesized via seeded surface nucleation in an emulsion polymerization of styrene, glycidyl methacrylate, and divinylbenzene by using PVDF microparticles as seeds. Both the feed ratio and the polymerization time are considered to manipulate the core–shell structures of the composite microparticles, which obviously influences the morphology of the YSMs obtained from the subsequent treatment of solvent etching to remove the seed. The hollow volume of the polymeric YSMs is easily adjusted by changing the etching time at different temperatures. Meanwhile, we realized three-dimensionally confined crystallization of PVDF in different morphologies of YSMs. Furthermore, YSMs with the same or different functional groups, inside and outside of the hollow shell, respectively, are chemically modified by the reaction of glycidyl groups on the shell with 2,2′-(ethylenedioxy) bis-ethylamine. Thus, strong fluorescence of the YSMs is observed by subsequent labeling with functional fluorescent groups.

Polymerization of styrene in aqueous system using a diethylzinc and 1,10-phenanthroline complex

Diethylzinc (DEZ) is highly combustible in air and easily hydrolyzed in water, therefore research using this DEZ compound in the polymerization field has hardly been conducted. The present study shows the stabilization of DEZ by forming complex with 1,10-phenanthroline and succeeded in emulsion polymerization of styrene using this diethylzinc-1,10-phenanthroline complex (Phen-DEZ). Ultra-high-molecular-weight polymers (Mw > 1 × 107) were obtained in high yield (80%) by using sodium dodecyl sulfate (SDS) as emulsifier in this emulsion system at 23 °C. The kinetics study of styrene emulsion polymerization initiated by Phen-DEZ was investigated. In the early stage of polymerization, an almost linear first-order kinetic plot was observed and the overall activation energy of this polymerization system was 31.0 kJ mol−1.

Application of Some Polymer latexes in Preventing Paper Documents Forgery

The main objective of this research is to improve ink printability of papers via their modification with various types of water-based polymer latexes during paper manufacturing process. In order to achieve this target, various types of styrene-acrylate polymer latexes were used for modification of different types of papers. Styrene-acrylate latexes were prepared via emulsion polymerization of styrene with various acrylate monomers using emulsion polymerization technique. The effect of different emulsifying agents on the properties of the prepared emulsions was studied. The obtained results showed a significant improvement in degree of gloss and ink density on the polymer-coated papers which positively affect the ink ability, and ink holding properties of the modified paper. In addition, ink gloss and ink density of the coated papers improved with increasing the concentration of modifying latexes containing Texapon®P as emulsifier. These promising results open the way to use polymer latexes in treatment of documented value which can be used in stabilization of disappearing ink on paper leading to prevent forgery

Dispersion of carbon nanofibers modified with polymer colloids to enhance mechanical properties of PVA nanocomposite film

Polymer colloids have been used to modify the surface of carbon nanofibers (CNFs), to enhance the mechanical properties of polyvinyl alcohol (PVA) resin/CNF nanocomposite materials prepared by the solution casting method. However, the CNFs showed uneven dispersal within, and adhesion to, the PVA resin.In this study, the colloidal technique using polymer particles was applied to achieve more uniform dispersion of CNFs in PVA resin. This results in the polymeric particles functioning as spacers, thereby inhibiting CNF clustering; and in hydrogen bonding between PVA and polymer particles, thereby increasing surface adhesion between CNF and PVA. Polymer colloids prepared by the emulsion polymerization of styrene and N-vinylacetamide showed particularly notable enhancements of dispersion and surface adhesion in the composites. Consequently, PVA composite film containing uniformly distributed CNFs showed significantly enhanced tensile strength and modulus even at CNF mass fraction of 5.0 wt%.