Aromatic Vinyl Monomers Research Articles

Chemoenzymatic Synthesis of Aromatic Vinyl Monomers from Biorenewable 5-Hydroxymethyl-2-Furfural

Chemoenzymatic Synthesis of Aromatic Vinyl Monomers from Biorenewable 5-Hydroxymethyl-2-Furfural

Free radical (Co)Polymerization of aromatic vinyl monomers derived from vanillin

Chemical structure (effect of functional substituents on vinyl bond reactivity) was used as a criterion to evaluate the (co)polymerization behavior of vanillin-derived 3-allyl-5-vinylveratrole, 4-vinylveratrole, and 2-glycidoxy-5-vinylanisole in chain-growth polymerization mechanism. After polymerization, allyl and epoxy functional groups of monomer units remain unaffected as macromolecular side groups and can be utilized in post-polymerization reactions (in particular, cross-linking). Due to the intermolecular chain transfer to polymer, a fraction of branched macromolecules can be formed in free radical polymerization of 3-allyl-5-vinylveratrole. At the same time, the kinetic study shows a similar polymerization rate for all the three investigated biobased aromatic vinyl monomers.Determined in copolymerization with methyl methacrylate Q-e values indicate that 3-allyl-5-vinylveratrole, 4-vinylveratrole and 2-glycidoxy-5-vinylanisole behave like conventional vinyl monomers and can be copolymerized interchangeably. In this manner, macromolecules with controlled amounts of cross-linkable epoxy and allyl groups incorporated into the backbone can be synthesized. Based on the glass transition temperature of the homopolymers thereof (66–93 °C), biobased aromatic vinyl monomers can serve as “rigid” macromolecular fragments and be applied in the formulation of thermoset polymer coatings. Being derived from renewable resources, 3-allyl-5-vinylveratrole, 4-vinylveratrole, and 2-glycidoxy-5-vinylanisole can be considered as a replacement for petroleum-based commodity styrene in the production of various industrial polymeric materials that utilize aromatic monomers.

Unprecedented Processable Hypercrosslinked Polymers with Controlled Knitting.

Processable microporous organic polymers (MOPs) attract incomparable research interest because their vairous types, such as monoliths and membranes are for practical application. Most processable MOPs usually need harsh conditions such as the use of expensive metal catalysts, specialized stereospecific monomers, etc., which restrict the sustainable and real applications of processable MOPs. Therefore, the economical mass production of processable MOPs remains a formidable challenge. Herein, a novel strategy is reported for constructing processable hypercrosslinked polymers (HCPs) need two steps synthesis of pre-crosslinking and deep-crosslinking using divinylbenzene (DVB) as a self-crosslinking monomer under the catalysis of a small amount of FeCl3 . The resulting HCPs monoliths possess high BET surface area of 1033-1056 m2 g-1 with hierarchical porosity, and show excellent mechanical strength up to 65MPa. It is, to the best of authors' knowledge, the first report of using aromatic vinyl monomers as self-crosslinking monomers to generate HCPs monoliths with high surface area, yielding no by-products, and high mechanical strength.

Stereoselective Polymerization of an Aromatic Vinyl Monomer to Access Highly Syndiotactic Poly(vinyl alcohol).

Streoregular poly(vinyl alcohol) is hard to obtain because vinyl alcohol is unstable relative to its tautomer acetaldehyde, and the monomer precursor vinyl ester is poisonous to the coordination catalyst. Herein, the coordination polymerization of 2-vinyl-2,1-borazanaphthalene (BN2VN) is reported by the linked or unlinked half-sandwich ligands attached scandium precursors ((FluSiMe3 )Sc(CH2 SiMe3 )2 (THF) (THF = tetrahydrofuran, 1), (FluCH2 CH2 -NHC-R)Sc(CH2 SiMe3 )2 (THF) (R = mesityl 2, i Pr 3, Me 4), and (FluCH2 Py)Sc(CH2 SiMe3 )2 (5) for the first time. Among these precursors, complex 5 converts 600 equivalents of BN2VN into polymer within 5 min to reach an activity as high as 8.99 × 105 g molSc -1 h-1 . The resultant products show excellent syndiotacticity and melting temperatures above 300 °C, which can be transferred to syndiotactic poly(vinyl alcohol) with 90% rr triad content by postpolymerization oxidation.

Rapid Polymerization of Aromatic Vinyl Monomers to Porous Organic Polymers via Acid Catalysis at Mild Condition.

Porous organic polymers (POPs) have enormous applications in various fields and thus have received a lot of research attention in recent decades. Numerous synthetic methods have been developed, but mild synthesis conditions and fast polymerization rate are highly desired. Herein, high porous POPs with high surface areas from aromatic vinyl monomers by using acid catalysis method is reported. The polymerization is ultrafast and could be accomplished even in 5 min at room temperature. Furthermore, the surface area can be tuned by using various acid catalysts and controlling the reaction time. Due to the high surface area, these POPs show promising adsorption of carbon dioxide and hydrogen, respectively. Furthermore, the large π-system of the building block and high surface area of the POPs also make them show potential applications in photocatalytic hydrogen evolution as well as promising catalyst support for metal nanoparticles.

Syndioselective Polymerization of a BN Aromatic Vinyl Monomer

A new synthetic platform accessing stereoregular polar polyolefins is introduced. We showcase the stability of aromatic azaborine derivatives by demonstrating the syndioselective polymerization of BN 2-vinylnaphthalene (BN2VN) by a monocyclopentadienyl titanium complex. Homogeneous early transition metal catalysts are well-established systems for the synthesis of highly stereoregular syndiotactic polystyrene (sPS), but the oxophilic nature of these complexes results in catalyst decomposition with polar monomers. BN2VN’s compatibility with coordination polymerization, and its ability to intercept the mechanism of styrene polymerization, is attributed to its aromaticity. Stereoretentive postpolymerization oxidation of the organoborane side chain generates syndiotactic poly(vinyl alcohol) (sPVA), an example of PBN2VN’s potential for diverse postfunctionalization.

A BN Aromatic Ring Strategy for Tunable Hydroxy Content in Polystyrene.

BN 2-vinylnaphthalene, a BN aromatic vinyl monomer, is copolymerized with styrene under free radical conditions. Oxidation yields styrene-vinyl alcohol (SVA) statistical copolymers with tunable hydroxy group content. Comprehensive spectroscopic investigation provides proof of structure. Physical properties that vary systematically with hydroxy content include solubility and glass transition temperature. BN aromatic polymers represent a platform for the preparation of diverse functional polymeric architectures via the remarkable reaction chemistry of C-B bonds.

A BN Aromatic Ring Strategy for Tunable Hydroxy Content in Polystyrene

AbstractBN 2‐vinylnaphthalene, a BN aromatic vinyl monomer, is copolymerized with styrene under free radical conditions. Oxidation yields styrene–vinyl alcohol (SVA) statistical copolymers with tunable hydroxy group content. Comprehensive spectroscopic investigation provides proof of structure. Physical properties that vary systematically with hydroxy content include solubility and glass transition temperature. BN aromatic polymers represent a platform for the preparation of diverse functional polymeric architectures via the remarkable reaction chemistry of C−B bonds.

Quaternized poly (styrene-co-vinylbenzyl chloride) anion exchange membranes for alkaline water electrolysers

In this study, poly (ST-co-VBC) based anion exchange membranes with different styrene to VBC ratios (1: 0.16, 1: 0.33 and 1: 1) have been prepared via chloromethylation-free synthetic route using aromatic vinyl monomers. The synthesized co-polymers are identified by FTIR and 1H-NMR analysis. Hydroxide (OH−) ion conductivity of the anion exchange membrane with styrene to VBC ratio of 1: 0.33 is as high as 6.8 × 10−3 S cm−1 in de-ionised water at 25 °C. The membrane also acquires the ion-exchange capacity of 2.14 meq. g−1, and the water uptake of 127%. Membrane-electrode-assembly (MEA) using the anion exchange membrane and Ni – foam catalyst demonstrate the current density of 40 mA cm−2 at 2.3 V in a water electrolyser cell.

Soap-free emulsion polymerization of aromatic vinyl monomer using AIBN

Soap-free emulsion polymerizations of aromatic vinyl monomers using 2,2′-azobis(2-methylpropionitrile) (AIBN) were investigated to clarify the origin of the negative charge of the synthesized particles. It was found that the zeta potential and size of the particles synthesized by soap-free emulsion polymerization using AIBN had a strong relationship with the pi electron cloud density in the aromatic vinyl monomer used in the polymerization. The effect of the position of the substituent atom in the phenyl ring on the synthesized particle properties was small.

Screening and Phylogenetic Analysis of Deep-Sea Bacteria Capable of Metabolizing Lignin-Derived Aromatic Compounds

Lignin is one of the most abundant biomasses in nature. It is composed of aromatic moieties and has great potential for use in the production of chemical alternatives to petroleum products. Because of increasing interest in biocatalysis, the potential for industrial application of microbial metabolism of lignin-derived compounds has gained considerable recent attention. Functional screenings of culturable bacteria isolated from sediments and sunken wood collected from the deep sea revealed the existence of a number of previously unidentified bacteria capable of metabolizing lignin-related aromatic compounds. Of the 510 isolates obtained in the present study, 208 completely or partially metabolized these compounds. The 208 isolates were classified into diverse phyla, including Firmicutes, Actinobacteria, Bacteroidetes, and Proteobacteria. Among the 208 isolates, 61 unique 16S rRNA gene sequences were detected including previously unidentified marine lineage isolates. The metabolites of the isolates were analysed using liquid chromatography/mass spectrometry (LC/MS) or gas chromatography/mass spectrometry (GC/MS). Most of the representative 61 isolates non-oxidatively decarboxylated the substrates to produce the corresponding aromatic vinyl monomers, which are used as feed stocks for bio-based plastics production. Oxidative metabolism of the lignin-related compounds for assimilation was frequently observed. Our study showed that the deep-sea environment contains an abundance of microorganisms capable of both non-oxidative and oxidative bioconversion of lignin-derived aromatic compounds. The ability for bio-conversion of aromatic compounds found in this study will facilitate the development of future biotechnological applications.

Polymer electrolyte hybrid membranes prepared by radiation grafting of p-styryltrimethoxysilane into poly(ethylene- co-tetrafluoroethylene) films

In order to prepare a polymer electrolyte hybrid membrane with both high proton conductivity and high thermal stability, an aromatic vinyl monomer having a trimethoxysilyl group, namely p-styryltrimethoxysilane, was first grafted into poly(ethylene- co-tetrafluoroethylene) (ETFE) film by γ-ray preirradiation. The p-styryltrimethoxysilane-grafted film was then sulfonated to attach sulfonic acid groups onto the aromatic rings of the graft chains, and finally hydrolyzed and condensed to introduce silane-crosslinking between the graft chains. Thus, a crosslinked proton-conducting polymer electrolyte hybrid membrane was obtained. The preparation conditions for grafting and sulfonation, and the properties of the resulting polymer electrolyte membrane, such as ion exchange capacity, proton conductivity, water uptake, and thermal stability were investigated with respect to its application in fuel cells. It is concluded that the properties of the new p-styryltrimethoxysilane-grafted polymer electrolyte hybrid membrane are comparable to Nafion, and are superior to a styrene-grafted membrane.

Polypropylene/polystyrene blends—Preliminary studies for compatibilization by aromatic‐grafted polypropylene

AbstractThe blends of Polypropylene (PP), that is a semicrystalline and nonpolar thermoplastic polymer with a polar and amorphous polymer such as Polystyrene (PS), are known to be immiscible. This article investigates the use of an aromatic vinyl monomer (AVM)‐grafted PP (PPA) as a potential compatibilizer for such an immiscible blend system (PP/PS blend). PPA was prepared by grafting a monofunctional aromatic vinyl monomer onto PP using an organic peroxide at 180°C for 10 min in a Brabender mixer. Using a twin‐screw extruder, blends of PP/PS in various composition containing different amount of PPA were prepared. Results obtained from tensile and impact strength, heat deflection, and melt flow index measurements shows some improvement in the properties of the blends indicating some compatibilization effects in the blend system. However, the scanning electron microscopy (SEM) micrographs strongly suggested a significant compatibilization between PP and PS. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 428–434, 2001

Copolymerization of ethylene with aromatic vinyl monomers using metallocenes

AbstractCopolymerization of ethylene with styrene, allyl benzene and 4‐phenyl‐1‐butene was examined using different metallocene catalysts. We separated the bulky phenyl group of styrene from its double bond using methylene spacers and studied the effect on its copolymerization behaviour with ethylene. The extent of incorporation of the comonomer is in the order 4‐phenyl‐1‐butene > allyl benzene > styrene for all catalysts. The comonomer incorporation was found to be less than 10 mol% under the experimental conditions employed in the present study.© 2001 Society of Chemical Industry

Quantitative analysis on the grafting of an aromatic group on polypropylene in melt by FTIR technique

The FTIR quantitative analytical method is described as an alternative technique for determination of percentages of grafted content in the grafting of an aromatic group on polypropylene. An aromatic vinyl monomer (designated SG1) was grafted onto a commercial isotactic polypropylene (PP) by an organic peroxide (Trigonox 101). Dried extracted samples were evaluated using FTIR qualitative and quantitative analytical methods. The grafting reaction was confirmed through FTIR spectra showing infrared bands which conformed to aromatic substituted benzene in the grafted copolymer. Weight percentage of monomer grafted to polypropylene and percentage grafting of monomer were obtained from computer-plotted regression curves. These values obtained by an FTIR quantitative analytical method through the measurements of infrared absorbance bands of grafted polymer (PP-g-SG1) at two different peaks (752 cm −1 and 690 cm −1), before and after extraction, were found to be consistent.

Alternating copolymers consisting of arylalkyl methacrylates. II. Effect of coil collapse on fluorescence spectra of alternating copolymers of 2‐(9‐carbazolyl)ethyl methacrylate and aromatic vinyl monomers

Alternating and random copolymers of 2-(9-carbazolyl)ethyl methacrylate with aromatic vinyl monomers were synthesized and their fluorescence properties were compared in good and poor solvents. Contraction of the polymer coils induced the hypochromic effect, i.e., the mutual interaction of the ground-state chromophores, but caused little quenching of their excited state. This is sharp in contrast with the vinyl-type of polymers, exhibiting large interactions in both the ground and excited states. Introduction of bulky groups on the comonomers in the alternating copolymers further suppressed these interactions. © 1996 John Wiley & Sons, Inc.

Alternating copolymers consisting of arylalkyl methacrylates. II. Effect of coil collapse on fluorescence spectra of alternating copolymers of 2-(9-carbazolyl)ethyl methacrylate and aromatic vinyl monomers

Alternating and random copolymers of 2-(9-carbazolyl)ethyl methacrylate with aromatic vinyl monomers were synthesized and their fluorescence properties were compared in good and poor solvents. Contraction of the polymer coils induced the hypochromic effect, i.e., the mutual interaction of the ground-state chromophores, but caused little quenching of their excited state. This is sharp in contrast with the vinyl-type of polymers, exhibiting large interactions in both the ground and excited states. Introduction of bulky groups on the comonomers in the alternating copolymers further suppressed these interactions.