Styrene Molecules Research Articles

Multiphoton Dissociative Ionization of Gas-Phase Styrene.

We performed multiphoton ionization of styrene molecules and observed the formation of styrene and benzene cations, the latter being reported for the first time in the multiphoton ionization of styrene. The formation of the benzene cation reveals an internal conversion from the S1 state to the S0 state, which occurs via a S1/S0 conical intersection at 4.66 eV above the minimum of the S0 state. The present results indicate the position of this conical intersection to be energetically lower than the theoretically calculated value and also the previous experimental observation. The role of dissociative ionization of styrene in the formation of benzene cations in the atmosphere is discussed.

Induced π–complexation properties of smectites impregnated by Ni, Cu and Ag transition metals: The highly efficient styrene uptake

Two natural smectite minerals (montmorillonite and beidellite) differing in structural charge location were impregnated with varying amounts of transition metals: Ni(II), Cu(I) or Ag(I). The modification aimed to increase the affinity of the minerals towards styrene vapors. The structure, texture, chemical composition and surface chemistry of the materials were studied by XRD, FTIR, Raman, N2 adsorption/desorption, XRF and XPS. The experiments examined the influence of the starting smectite and the type of introduced metal on styrene adsorption efficiency. The styrene uptake mechanisms were investigated through solid state analysis and supported by DFT calculations. The study demonstrated that the small content of introduced metals (<2% wt.) substantially increased styrene uptake (∼200–350% wt.) surpassing values reported for surfactant-intercalated smectites (∼40–80% wt.) and activated carbons (∼30% wt.). This enhancement was attributed to the π-complexation between dispersed d-block metals and π-electron-rich styrene molecules, subsequently leading to polystyrene formation. The DFT calculations were consistent with experimental findings, indicating a higher affinity of the raw beidellite towards styrene than the raw montmorillonite connected to the charge location. Moreover, the observed trends in calculated adsorption energies and lengths of weak hydrogen bonds allowed to explain a significant adsorption increase observed for the Ni- and Cu-impregnated montmorillonite-based materials.

Tuning light-driven oxidation of styrene inside water-soluble nanocages

Selective functionalization of innate sp2 C-H bonds under ambient conditions is a grand synthetic challenge in organic chemistry. Here we combine host-guest charge transfer-based photoredox chemistry with supramolecular nano-confinement to achieve selective carbonylation of styrene by tuning the dioxygen concentration. We observe exclusive photocatalytic formation of benzaldehyde under excess O2 (>1 atm) while Markovnikov addition of water produced acetophenone in deoxygenated condition upon photoexcitation of confined styrene molecules inside a water-soluble cationic nanocage. Further by careful tuning of the nanocage size, electronics, and guest preorganization, we demonstrate rate enhancement of benzaldehyde formation and a complete switchover to the anti-Markovnikov product, 2-phenylethan-1-ol, in the absence of O2. Raman spectroscopy, 2D 1H-1H NMR correlation experiments, and transient absorption spectroscopy establish that the site-selective control on the confined photoredox chemistry originates from an optimal preorganization of styrene molecules inside the cavity. We envision that the demonstrated host-guest charge transfer photoredox paradigm in combination with green atom-transfer reagents will enable a broad range of sp2 carbon-site functionalization.

In Ukrainian

Thermal destruction of composites of ureaformaldehyde (UPR) and polyester resins (PER) with silicon dioxide nanoparticles having a specific surface area of 280 m2/g, titanium dioxide and titanosilicate with a specific surface area of 40 and 48 m2/g, respectively, when a filler content is no more than 5.0 wt% have been studied. The investigations were performed using The thermally programmed mass spectrometry method with registration of the masses of desorbed atomic fragments in the 10 ‒ 200 m/z range. It was established that during the main polymer mass destruction at 150 ‒ 350 oC, along with low temperature decomposition products, anomalously high thermal resistance of a number of atomic fragments of polymer chains and cross-links are recorded. The atomic composition of destruction fragments and their desorption temperature in the range 400 ‒ 700 oС were determined. It was established that in composites of ureaformaldehyde resin with SiO2 and TiO2 nanoparticles the high temperature resistance of fragments with m/z 27 exhibits due to the formation of strong bonds among the Si and Ti surface sites and the nitrogen atoms of the polymer. Such thermal stability is not realized in resin loading with (Si/Ti)O2 nanoparticles. In composites of polyester resin with silica a high-temperature destruction of oxygen atoms from polyester chains realizes at temperatures of 290 ‒ 400 oC and a low-intensity wide destruction band takes place in the temperature range 400 ‒ 700 oC. In addition, in the temperature range of 400-700 oC cross-links are destroyed with the release of benzene rings and styrene molecules. It was established that anomalously high-temperature desorption is typical for atomic fragments of the polymer structure attached to surface Si and Ti sites through nitrogen or carbon atoms from the polymer structure. Thus, in UPR composites with silicon and titanium oxides, strong chemical nitride bonds of the form Si-N≡C-H and Ti-N≡C-H are formed, which demonstrate anomalously high heat resistance. It is shown that in composites of polyester resin with silicon dioxide nanoparticles, the high-temperature destruction of fragments is due to their desorption from the surface of silicon dioxide particles when breaking their bonds with silicon atoms. Thus, polymer matrices have been determined, in which atomic fragments of the macromolecule, binding to the surface centers of fillers, significantly weaken the thermal destruction of composites due to the formation of strong chemical and coordination bonds.

Polystyrene Waste Thermochemical Hydrogenation to Ethylbenzene by a N-Bridged Co, Ni Dual-Atom Catalyst.

Recycling waste plastics requires the degradation of plastics into small molecules. However, various products are widely distributed using traditional methods of depolymerizing polystyrene (PS) such as catalytic pyrolysis and hydrogenolysis. Here, we creatively report a N-bridged Co, Ni dual-atom (Co-N-Ni) catalyst for the targeted conversion of waste PS plastics to ethylbenzene via a pressurized tandem fixed-bed reactor where hydropyrolysis is coupled with downstream vapor-phase hydrotreatment. The Co-N-Ni catalyst achieves 95 wt % PS conversion with 92 wt % ethylbenzene yield, significantly superior to the corresponding single-atom catalysts, and enables degradation of real PS plastics. Theoretical calculations and experimental results demonstrate that the d-band center of metal atoms is well regulated in the Co-N-Ni catalyst. The Co site activates the C═C bond more easily, while the Ni site spatially optimizes the adsorption configuration of the styrene molecule due to the electronic interaction. This Co-N-Ni catalyst in the tandem reactor also shows excellent durability and provides a new direction for real plastic degradation.

Insight into the degradation process of functional groups modified polystyrene microplastics with dissolvable BiOBr-OH semiconductor-organic framework

The difficult separation of products after photocatalytic degradation of microplastics (MPs) limits the in-depth analysis of the MPs fragmentation process and degradation mechanism, and there are no studies about the photocatalytic degradation of functional groups modified MPs. In this work, we synthesized a “dissolvable” BiOBr-OH semiconductor-organic framework (SOF) to degrade polystyrene (PS) MPs modified by different functional groups, including –OH, –NH2, -SO3H, –COOH and -epoxy. First, a series of characterization confirmed that small molecules were intercalated into BiOBr layers to construct BiOBr-OH SOF. The BiOB-OH SOF system has significantly enhanced the photocatalytic degradation performance of microplastics, and BiOB-OH-0.75 has the strongest catalytic performance. The photocatalytic degradation performance of different functional groups modified PS-MPs differed significantly, with the weight loss order being -epoxy > –NH2 > –OH > –COOH > -SO3H. After dissolving the catalyst, clean nano plastic particles were obtained after degradation, and it was found that six types of PS-MPs exhibited three different types of fragmentation processes. The surface potential of and fragmentation mode of different PS-MPs dominated the adsorption and photocatalytic degradation of BiOBr-OH SOF. The degradation products of PS-MPs are mainly composed of styrene and functional group-modified monomer molecules and multimolecular complexes. In addition, by analyzing the toxicity of the degradation products of microplastics, it was found that solid products were the main reason for their enhanced toxicity. Finally, based on the photoelectrochemical characterization and free radical analysis, the mechanism of photocatalytic degradation of different functional groups modified PS-MPs by BiOBr-OH SOF was proposed.

Multiple linear regression and artificial neural networks for highly selective cationic β‐diimine‐methallyl nickel (II) catalyst for styrene dimerization reaction to 1,3‐diphenyl‐1‐butene

The objective of the present study is to develop predictive models to input and output parameters for linear styrene dimerization reactions. These reactions involve the conversion of two styrene molecules into 1,3‐diphenyl‐1‐butene, which is a commonly used intermediate in the production of various industrial chemicals. Multiple linear regression (MLR) and artificial neural network based on multilayer perceptron (MLP) and radial basis function were used to model 1,3‐diphenyl‐1‐butne dimerization process in order to evaluate its performance. The neural network has been trained and tested by experimental data. The effect of various parameters (such as complex concentration) on styrene conversion (Conv%) and turnover of frequency (TOF) has been investigated in the proposed work. The results found by the proposed predictive models were analyzed and compared with the experimental results. Based on the comparison of the results, the radial basis function neural network (RBFNN) model outperformed the other models (MLR and MLP) with a correlation coefficient of (0.987 for Conv% and 0.947 for TOF) and lower root mean square errors for the output parameters. This result demonstrates that the RBFNN is an efficient technique to predict the styrene conversion and turnover frequency of the dimerization reaction. It was exposed that the control strategies learned are robust and can be transferred to similar dimerization reaction configurations.

Adsorption removal of styrene on C–Cl grafted silica gel adsorbents

The heat desorption of styrene from adsorbents is impracticable owing to its spontaneous polymerization under heating conditions. However, the feature also brings a potential promoting effect on styrene adsorption. Therefore, it is expected to develop the non-regenerative adsorbents with large adsorption capacity by strengthening the polymerization effect. In this work, C–Cl grafted silica gel adsorbents were prepared by introducing (Chloromethyl)dimethylchlorosilane (CMDMCS) and FeCl2 into silica gel. The C–Cl grafted silica gel exhibited excellent styrene adsorption performance, its adsorption amounts for styrene were 4.67 times and 9 times of unmodified silica gel under dry air condition and high humidity condition (RH = 80%), respectively. In addition, the adsorption of styrene on C–Cl grafted silica gel was almost unaffected by the presence of toluene. The characterization of adsorbents after styrene adsorption indicated that the improvement of adsorption capacity of C–Cl grafted silica gel for styrene can be attributed to atom transfer radical polymerization (ATRP) of styrene molecules on modified silica gel during adsorption process.

Mechanistic Impacts of Metal Site and Solvent Identities for Alkene Oxidation over Carboxylate Fe and Cr Metal–Organic Frameworks

Isolated Fe(III) and Cr(III) sites contained in nanoporous voids of isoreticular carboxylate MIL-101(Fe) and MIL-101(Cr) are interrogated for their reactivity and selectivity of liquid-phase styrene oxidation by hydrogen peroxide (H2O2). Batch kinetic measurements in acetonitrile (MeCN) at 323 K showcase that both metal-normalized oxygenate production and H2O2 consumption rates are O(101) higher for MIL-101(Fe) than MIL-101(Cr). Thermodynamically consistent reaction pathways, constructed through spiking experiments, reveal complex interconnectivities between primary (styrene oxide, benzaldehyde) and secondary (styrene glycol, benzoic acid, phenylacetaldehyde) oxygenates. Though benzaldehyde is the majority product for both MIL-101(Fe) and MIL-101(Cr), isoconversion (Xstyrene = 7%) product distributions suggest intrinsic differences in preferred reaction pathways. Apparent energy barriers for all pathways are lower over MIL-101(Fe) than for MIL-101(Cr), conferred by metal electron affinity differences for primary oxygenate selectivity, while secondary (inter)conversion rates trend with acid site densities. Fitted rate laws, radical trapping, adsorption experiments, and complementary DFT calculations indicate surface-mediated reactions by H2O2-derived surface species that outcompete bound styrene, product oxygenate, solvent, and water molecules for both MIL-101(Fe) and MIL-101(Cr) in MeCN. Extracted enthalpic and entropic effects from temperature-dependent experiments (318–328 K) in MeCN and MeOH showcase the ability of hydrogen bonding solvents in locally hydrophilic environments to selectively stabilize primary oxygenate transition states and indicate additional confinement effects from microporous substructures in MIL-101(Fe) and MIL-101(Cr). Simplified rate expressions are expanded to encompass first-order catalyst deactivation rates through temporal metal leaching experiments and assert that metal leaching dominates MIL-101(Cr) catalyst inefficiencies, while a combination of metal leaching and other (ir)reversible site changes are present for MIL-101(Fe). Overall, this work combines kinetic, spectroscopic, numerical, and computational approaches to rigorously define reaction and deactivation mechanisms for styrene oxidation by H2O2 over isoreticular MIL-101(Fe) and MIL-101(Cr).

Palladium-Doped Single-Walled Carbon Nanotubes as a New Adsorbent for Detecting and Trapping Volatile Organic Compounds: A First Principle Study.

Volatile organic compounds (VOCs) are in the vapor state in the atmosphere and are considered pollutants. Density functional theory (DFT) calculations with the wb97xd exchange correlation functional and the 6-311+G(d,p) basis set are carried out to explore the potential possibility of palladium-doped single-walled carbon nanotubes (Pd/SWCNT-V), serving as the resource for detecting and/or adsorbing acetonitrile (ACN), styrene (STY), and perchloroethylene (PCE) molecules as VOCs. The suggested adsorbent in this study is discussed with structural parameters, frontier molecular orbital theory, molecular electrical potential surfaces (MEPSs), natural bond orbital (NBO) analyses, and the density of states. Furthermore, following the Bader theory of atoms in molecules (AIM), the topological properties of the electron density contributions for intermolecular interactions are analyzed. The obtained results show efficient VOC loading via a strong chemisorption process with a mean adsorption energy of −0.94, −1.27, and −0.54 eV for ACN, STY, and PCE, respectively. Our results show that the Pd/SWCNT-V can be considered a good candidate for VOC removal from the environment.

Periodically Functionalized Sequence‐Regulated Vinyl Polymers via Iterative Atom Transfer Radical Additions and Acyclic Diene Metathesis Polymerization

AbstractSequence‐regulated vinyl polymers with functional groups, such as aliphatic, aromatic, hydroxy, amino, and carboxylic acid groups, as found in natural macromolecules such as proteins, are one of the ultimate targets in synthetic polymers. This study is directed toward the synthesis of periodically functionalized sequence‐regulated vinyl polymers using a series of reactions consisting of iterative atom transfer radical additions (ATRAs) of vinyl monomers, allylation, functionalization, protection, acyclic diene metathesis (ADMET) polymerization, hydrogenation, and deprotection. The functionalized sequence‐regulated telechelic diene oligomers, possessing protected hydroxy, carboxylic acid, and amino groups in the pendant of the acrylate unit between two styrene units, are prepared by iterative ATRAs of two styrene molecules to methyl dichloroacetate followed by allylation of both C–Cl termini and substitution of methyl ester with the protected functionalized groups. The protected functionalized sequence‐regulated telechelic diene oligomers are then polymerized by ADMET polymerization to afford polymers with main‐chain internal olefins and protected functionalized side chains in the acryl units between the two styrene units. The subsequent hydrogenation and deprotection reactions produce a series of sequence‐regulated vinyl polymers with periodic polar functional groups such as –OH, –CO2H, and –NH3+Cl–. These functional groups affect the thermal properties and solubility of the polymers.

Thermal Analysis of Plastics Used in the Food Industry.

Fires in landfills, where used plastic packaging waste is discarded, have shown how great a fire hazard these types of materials pose. In this study, the course of thermo-oxidation of samples made of polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET) based plastics was determined. Based on an analysis of the dissociation energy of bonds between atoms in a polymer molecule, the mechanisms responsible for the character and course of degradation were observed. It was found that the degradation rate of PP and PS could be a result of the stability of C-H bonds on the tertiary carbon atom. In the case of PS, due to facilitated intramolecular hydrogen transfer, stabilization of hydroperoxide, and formation of a stable tertiary alcohol molecule, the onset of degradation is shifted towards higher temperatures than in the case of PP. Notably, the PP fragmentation occurs to a greater extent due to the easier course of β-scission. In addition, it was found that during a fire, the least amount of heat would be generated by thermo-oxidation of PS-based plastics. This is a result of the formation of a styrene molecule during decomposition that, due to the high stability of bonds in the aromatic ring, escapes from the combustion zone without oxidation. It has been proven that the greatest thermal effect accompanies PET decomposition, during which a phenyl radical is produced, where the C-H bonds break more easily in comparison with the bonds of an intact ring.

Enhancing the hydrophilicity and biofoulant removal ability of a PVDF ultrafiltration membrane via π-π interactions as measured by AFM

Antibiotics are commonly used as inhibitors to terminate protein formation in the biotechnology and pharmaceutical industries; however, due to the large difference in molecular weight between antibiotics and proteins, it is hard to remove them simultaneously through ultrafiltration or nanofiltration. In this work, a novel membrane with nanoscale pores and anti-protein adsorption was developed to reject antibiotics and reduce protein adhesion. Amphiphiles consisting of hydrophobic and hydrophilic moieties were synthesized from a poly(styrene-alt-maleic anhydride) (SMA) copolymer with a 2-hydroxyethyl acrylate (HEA) monomer to enhance the hydrophilicity of polyvinylidene difluoride (PVDF) membranes. A series of SMAs with different polystyrene molar ratios (maleic acid/styrene (m/s) = 1:1, 1:2 and 1:3) was synthesized in this study, and the bonding force between the amphiphiles and PVDF, namely, π-π interactions between styrene molecules and the C–F bonds of PVDF, was evaluated. The π-π interaction between the amphiphiles and the PVDF membrane was determined via atomic force microscopy (AFM) repulsive force measurements for the first time in this work. The repulsive force increased significantly from -5.9 ± 1.0 nN to −18.3 ± 0.8 nN as the m/s ratio increased to 1:3, indicating that the π-π interaction was enhanced as the proportion of polystyrene in the SMA-HEA copolymer increased, resulting in tight attachment. Furthermore, the amphiphile-modified membrane demonstrated better hydrophilicity than the pristine PVDF membrane, and the water contact angle (WCA) decreased considerably from 104° (PVDF) to 55° (m/s = 1:2, P2000-600). The pure water flux recovery rate of P2000-600 improved by approximately 10%, and antibiotic rejections of 92.8%, 99.9% and 97.1% for tetracycline (TC), chloramphenicol (CL) and erythromycin (EM), respectively, were observed during the 7-h filtration process, indicating that P2000-600 can effectively remove antibiotics from water. In addition, P2000-600 also displayed good restriction of bovine serum albumin (BSA) adsorption at 28.4 ± 8.1 μg/cm2 under static adsorption processes and BSA rejection of nearly 90% during the three-cycle filtration.

Structural design of flame‐retardant phosphatized unsaturated polyester resin

AbstractTo improve flame‐retardant properties of unsaturated polyester resin (UPR), two phosphorus‐containing vinyl monomers with different chemical structures were synthesized to replace styrene molecules and then copolymerized with UPR oligomers to prepare flame‐retardant phosphatized UPRs. Curing behavior of phosphatized UPRs was investigated by DSC non‐isothermal curing curves, deducing the best curing conditions. Cone calorimeter results demonstrated the obvious reduction of heat release rate and smoke production rate by comparing phosphatized UPRs with flammable UPR. TG‐IR‐MS coupling technique was utilized to reveal thermal degradation and pyrolytic volatiles including aromatic compounds, hydrocarbons, CO, PO4˙, and so forth, providing more information of smoke toxicity and the gas phase flame‐ retardant mechanism of phosphatized UPRs. Moreover, the yield, compactness and graphitic degree of char residues of phosphatized UPRs were increased, strengthening the barrier effect to inhibit the permeation of combustion heat and the effusion of pyrolytic volatiles in the condensed phase.

Photocatalytic activity of synthetic ZnO/WO3 nanocomposites immobilized on a Y-zeolite in removal of gas-phase styrene.

The widespread use of styrene along with its harmful effects on human health has led to many studies on how to control and reduce its vapors in the workplace. In this study, efficient removal of styrene molecules in the gas phase was attempted by using Y-ZnO/WO3 hybrid photocatalysts. ZnO/WO3 nanocomposites with different WO3 Wt% were prepared and immobilized on Y-zeolite. The samples' characteristics were evaluated using X-ray diffraction (XRD), energy dispersive X-ray spectrum (EDS), Brunauer-Emmet-Teller (BET) and field emission scanning electron microscopy (FESEM). The Y- ZnO/WO3 catalyst exhibits an improved photocatalytic activity as compared to Y-ZnO and Y-zeolite alone. This higher photocatalytic activity of the ZnO/WO3 supported on Y-zeolite can be attributed to a more efficient interaction of the ZnO/WO3 with the zeolite leading to higher adsorption capacities. Results reveal that the photocatalyst was highly photoactive in mineralizing styrene. The high activity can be attributed to the synergetic effects of strong UV, ZnO/WO3 nanocomposite and surface hydroxyl groups. The photocatalytic degradation reaction of styrene with the Y-ZnO/WO3 follows Langmuir-Hinshelwood kinetics. The results of this study indicate that this photocatalyst is suitable for the removal of styrene under UV light. The highest removal efficiency achieved was with Y-ZnO/WO3 at 2%.

Theoretical study of boron, beryllium and lithium clusters (n=2–6), adsorption on graphitic carbon nitride and the study of acceptor-donor orbital of the coordination of a styrene molecule on [cluster/g-C3N4] systems

The adsorption of boron, beryllium and lithium clusters on graphitic carbon nitride g-C3N4, and the adsorption of styrene molecule on the B, Be, Li cluster/g-C3N4 sheet have been investigated through the density functional theory (DFT) calculations. Our calculations show distortion of the geometry of the clusters when coordinating with the g-C3N4 sheet. Boron (n = 5 and 6), beryllium (n = 2–4, 6) and Li3 cluster on g-C3N4 present characteristics to adsorb a styrene molecule. The styrene on Be4/g-C3N4 system exhibits better adsorption, due to the beryllium atoms have strong interactions with the π-orbitals of the aromatic ring of the styrene molecule. The study of natural bond orbitals of styrene-cluster/g-C3N4 systems showed the donation process from the styrene molecule and the g-C3N4 sheet towards the boron, beryllium and lithium clusters. Only back donation was observed the boron and beryllium clusters.

Regulating Electronic Status of Platinum Nanoparticles by Metal–Organic Frameworks for Selective Catalysis

Selective hydrogenation of alkynes to alkenes remains challenging in the field of catalysis due to the ease of over-hydrogenated of alkynes to alkanes. Favorably, the incorporation of metal nanopar...

High styrene/ethylbenzene selectivity in a metal-organic framework with coordinatively unsaturated cobalt(II) sites

Styrene (ST) is one of the most important feedstocks in the petrochemical industry and must be separated from a mixture of ST and ethylbenzene (EB). While the current technology comprises the energy-intensive vacuum distillation process, energy-saving adsorptive separation can be an alternative for ST/EB separation. The potential of a series of isostructural metal-organic frameworks (MOFs), M-MOF-74 (M = Mg, Co, Cu, or Zn), featured by highly dense unsaturated metal sites were evaluated for use in ST/EB separation using liquid-phase adsorption experiments. While all four M-MOF-74 materials showed selective adsorption of ST over EB, Co-MOF-74 exhibited the highest ST/EB selectivity (6.9) and the largest ST uptake (2.5 mmol/g), which were superior to those of benchmark MOF materials. This can be explained by the preferential interaction between unsaturated Co2+ sites and unsaturated ST molecules. Moreover, Co-MOF-74 retained its adsorption performance, porosity, and structural integrity after three consecutive adsorption and desorption experiments. These findings suggest that creating high density of Co2+ sites within a proper pore size would be an efficient strategy for developing an adsorbent for ST/EB separation.

Enzymatic plasticising of lignin and styrene with adipic acid to synthesize a biopolymer with high antioxidant and thermostability

Green synthesis of biopolymeric material based on renewable resources and can replace the present conventional plastic materials are today's urgent need. For that lignin was first depolymerised into its macromonomeric units using laccase. And through lipase mediated trans-esterification reaction, monolignol/oligolignols are plasticized with adipic acid at one end and further at another end of adipic acid, styrene molecules was plasticized by atomic transfer radical polymerization (ATRP). FTIR spectroscopy shows a disappearance of hydroxyl band (3437.75 cm−1) and appearance of ether band (1300-1000 cm−1) in the biopolymeric product which revealed that the polymerization occurs due to the formation of ether bonds in between the [-lignin-adipic acid-styrene-] monomeric units. Thermogravimatric analysis (TGA) and Dynamic mechanical analysis (DMA) shows that the polymeric film synthesised is highly thermostable with a glass transition temperature (Tg) of 99.7 °C. On XRD analysis it was observed that the degree of crystallinity increases on adding adipic acid moiety into the polymer and was calculated about 21.88% using DSC. SEM analysis shows lignin was properly dispersed within the styrene resulting into the homogeneous surface. Average molecular weight of the lignin–styrene based polymer was obtained 748063.2 g/mol using GPC and elemental analysis. Biological characterization of the polymeric film has shown strong antioxidant activity with least cytotoxicity on peripheral blood mononuclear cells (PBMCs) which enhanced its biocompatibility. The polymer synthesised can be a potential candidate for renewable and sustainable polymeric material and biomaterial.

Phenyl-modified hybrid organic-inorganic microporous films as high efficient platforms for styrene sensing

Abstract Microporous organic-inorganic hybrid silica films have been designed as active platforms to realise a styrene gas sensor. The microporous film has been synthesized by using tetraethylorthosilicate and phenyltriethoxysilane as precursors and a triblock copolymer (Pluronic F127) as a template for the pores. Multilayer films have been employed to increase the performance of the sensor and infrared spectroscopy has been used to probe the absorbed styrene molecules. The sensing response has been investigated by repeated exposures to different concentrations of styrene gas from 10 to 100 ppm. The microporous film has shown a better response compared to dense layers because of the increased surface area and the presence of the phenyl groups that enable a selective adsorption-desorption of the styrene. The diffusion coefficient of the microporous hybrid films has been calculated using a monodimensional plane-sheet diffusion model. This study shows that the microporous hybrid films have great potential to be used as simple and effective sensing materials for styrene and other Volatile Organic Compounds.