Influence Of Monomer Research Articles

Interfacial Pickering Emulsion Polycondensation for Degradable Nanocomposites.

Pickering emulsion polymerization is a practical method to fabricate functional composite materials. However, most reported systems proceed homogeneously within the stabilized monomer phase and create nondegradable chemical bonds. Here, interfacial Pickering emulsion polycondensation between aromatic aldehydes and polymercaptans is developed using sustainable cellulose nanoparticles as the stabilizer. When sulfonated cellulose nanocrystals (S-CNCs) were utilized, they also catalyzed the polycondensation to produce the oxidatively degradable S,S-acetal groups on the polymer chains. The influence of monomer and cellulose structures on the polymerization behavior and composite properties were compared.

Hydrophobic Aerogels from Vinyl Polymers Derived from Radical Polymerization: Proof-of-Concept.

Hydrophilicity is one important drawback of bio-based aerogels. To overcome this issue, a novel approach for the preparation of mesoporous, water repellent aerogels is introduced, which combines synthesis of cross-linked bio-based copolymers from methacrylate copolymerizations, followed by solvent exchange and supercritical drying steps. The influence of monomers with different nonpolar ester groups (methyl, vanillin, tetrahydrofurfuryl) on textural properties and water contact angles of the dry products is assessed. Final aerogels show generally high overall porosities (≈96%), low densities (0.07-0.11gcm-3) as well as fine, mainly mesoporous networks, and specific surface areas in the range of 120-240m2g-1. Hereby, choice of the methacrylate ester groups results in differences of the resulting pore-size distributions. Water repellency tests show stable static water contact angles in the hydrophobic range (≈100°) achieved for the substrate containing the vanillin ester group. On the contrary the other substrates absorb water quickly, which indicates a decisive role of the ester group. The presented approach opens up a new pathway to bio-based aerogels with intrinsic hydrophobicity. It is suggested that the properties are tailored by the choice of the monomer structure, hence enabling further adaption and optimization of the products.

Determination of complex refractive index of plastics from ultraviolet to mid-infrared by ellipsometry

Plastic litter is a pervasive issue in the ocean, posing threats to both marine ecosystems and human health. In the field of marine remote sensing detection, one common method for detecting and identifying marine plastics is by analyzing their optical characteristics, specifically their spectral remote sensing reflectance. This reflectance is dependent on the complex refractive index of plastics. Therefore, understanding the complex refractive index, which is an intrinsic optical property of plastics, holds significant importance in marine plastics research. In this study, we utilized spectroscopic ellipsometry to measure the complex refractive index of 9 common ploymers including polymethyl methacrylate (PMMA), methyl methacrylate–styrene copolymer (MS), polyethylene (PE), poly (ethylene glycol-co-cyclohexane-1,4-dimethanol terephthalate) (PETG), polybutylene terephthalate (PBT), polyoxymethylene (POM), perfluoroalkoxy (PFA), acrylonitrile butadiene styrene (ABS), and styrene-acrylonitrile copolymer (SAN). In addition, we have expanded the complex range of refractive index measurements to include UV and MIR bands with wavelengths up to 32 μm. To ensure the reliability and accuracy of the measurements, experimental results for polycarbonate (PC) were compared with data from the existing literature. The variation of refractive index with wavelength is studied and the causes of absorption peaks in the infrared range are discussed. Furthermore, Considering the dispersion relationship and monomer composition of PMMA, MS, ABS and SAN plastics, a comparative analysis of plastics with commonly used monomers is conducted, and the influence of monomers on refractive index is discussed. Our study indicates that the presence of styrene monomers leads to an increase in the refractive index of plastics in the visible to near-infrared band, while the presence of butadiene monomers results in a decrease.The findings from this study provide fundamental data for future research on marine plastic remote sensing detection applications.

Influence of the acrylamide-based monomer on the sintering of ceramics shaped by gelcasting

Alumina ceramics were prepared by gelcasting, based on an in-situ polymerization that promotes the formation of homogeneous green ceramic parts and allows the preparation of complex shapes and/or large-size ceramics. The influence of the monomer on the sintering behaviour of alumina pellets has been studied by considering three acrylamide-based monomers, i.e. acrylamide (AM), methacrylamide (MAM) and dimethylacrylamide (DMAA). Slurries with an alumina solid content of 50 vol% have been cast and pre-sintered pellets (1000 °C) with relative densities around 55% were obtained. These presintered pellets exhibit different granular packing, depending on the initial monomer used, as demonstrated by X-ray tomography, SEM and Hg porosimetry analyses. This results in significant differences in sintering behaviour, giving rise to very different final densities after 1 h sintering at 1530 °C: from 88% to 98%. This behaviour is described in terms of shrinkage rate, linked to the granular packing induced by the gelation process.

Influence of monomers and solvents in the direct sol-gel synthesis of LiNO3 shape stabilized phase change materials

Sol-gel techniques based on silicon dioxide SiO2 have been proposed for encapsulation of organic phase change materials (PCMs), avoiding phase segregation, and enhancing its thermal properties. Otherwise, the encapsulation of inorganic PCMs by direct sol-gel method has barely been applied for this purpose. Moreover, the evaluation of synthesis parameters (monomers, solvents, temperature and monomer/crosslinker ratio, among other) has never been done in order to improve the performance of the inorganic shape stabilized phase change materials (SS-PCMs) obtained by this technique. In this work, tetraethyl orthosilicate, trimethoxy [3-(methylamino)propyl] silane, (3-glycidyloxypropyl) trimethoxysilane and trimethoxy (2-phenylethyl) silane were employed as monomers for synthesis; and ethanol, acetonitrile and cyclohexane were used as solvent, for the evaluation of the sol-gel process. LiNO3 was selected as PCM, estimating the salt content of 50 and 70 wt% in the final material. Samples were characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD) and differential scanning calorimetry (DSC). The achievement of LiNO3 SS-PCM was confirmed by XRD; while a mixed composite of the lithium salt and SiO2 particles was observed by SEM, with a morphology depending not only in the employed monomers but in the PCM content. High values of latent heat (206.2 J g−1) were achieved during the SS-PCM synthesis with ethanol, 70 wt% of PCM content and employing only TEOS as monomers; and a reduction in latent range RL, respect to the pure LiNO3 salt, was observed. The thermal performance of the materials demonstrated its potential as SS-PCM for medium-temperature thermal energy storage applications.

Influence of Monomers on the Decomposition Rate of Polymerization Initiators: Quantum-Chemical Calculation of Optimal Structures of Forming Complexes and Their Degradation and Polymerization Initiation Mechanisms

Using EPR spectroscopy, it has been established that monomers affect the decomposition rate of their polymerization initiators by forming complexes with them. Several structures of the complexes have been optimized, and their decomposition mechanisms, the activation energies of the chain initiation and propagation reactions, and the heat of polymerization have been determined by means of quantum chemistry methods. In the absence of radical inhibitors (evacuation), the polymerization proceeds with high efficiency (98%) at room temperature without stimulation of the system with external energy.

Influence of ultrasonic condition on phase transfer catalyzed radical polymerization of methyl methacrylate in two phase system – A kinetic study

An ultrasonic condition assisted phase transfer catalyzed radical polymerization of methyl methacrylate was investigated in an ethyl acetate/water two phase system at 60±1°C and 25kHz, 300W under inert atmosphere. The influence of monomer, initiator, catalyst and temperature, volume fraction of aqueous phase on the rate of polymerization was examined in detail. The reaction order was found to be unity for monomer, initiator and catalyst. Generally, the reaction rate was relatively fast in two phase system, when a catalytic amount of phase transfer catalyst was used. The combined approach, use of ultrasonic and PTC condition was significantly enhances the rate of polymerization. An ultrasonic and phase transfer catalyzed radical polymerization of methyl methacrylate has shown about three fold enhancements in the rate compared with silent polymerization of MMA using cetyltrimethylammonium bromide as PTC. The resultant kinetics was evaluated with silent polymerization and an important feature was discussed. The activation energy and other thermodynamic parameters were computed. Based on the obtained results an appropriate radical mechanism has been derived. TGA showed the polymer was stable up to 150°C. The FT-IR and DSC analysis validates the atactic nature of the obtained polymer. The XRD pattern reveals the amorphous nature of polymer was dominated.

Influence of monomer on structure, processing and application characteristics of UV curable urethane acrylate composite coatings

Increased interest in the esthetical natural nail coatings have encouraged more in-depth studies particularly of UV curable coatings: their formation, processing, structure, characteristics and removing. Typical requirement for nail coatings is good adhesion, but preferably for the short time of functioning (usual 2-4 weeks). This study investigated the impact of four different monomers (tertiobutyl cyclohexyl acrylate (TBCHA), ethylene glycol dimethacrylate (EGDMA), tetrahydrofurfuryl acrylate (THFA), hydroxypropyl methacrylate (HPMA)) to viscosity of uncured mixture and degree of conversion, mechanical properties, surface gloss, micro hardness and adhesion loss for cured films. Specific coating application requires comparatively high coating flexibility and stability of deformation characteristics. This can be achieved with composition containing 30% of monomer TBCHA, what shows ultimate elongation εB = 0,23 - 0,24, modulus of elasticity E = 670-710 MPa and comparatively constant properties in 72 hours (ΔE = 1.3%, ΔεB=6.0%). A composition with 40% of TBCHA shows the fastest coating destruction achieving adhesion loss within 3 min.

Structural characterization of copolymer embedded magnetic nanoparticles

Small magnetic nanoparticles (Fe3O4) were synthesized by co-precipitation and coated by emulsion polymerization with poly(methyl methacrylate-co-acrylic acid) (PMMA-co-AAc) to create surface functional groups that can attach drug molecules and other biomolecules. The coated and uncoated magnetite nanoparticles were stored for two years in normal closed ships and than characterized by Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, vibrating sample magnetometry, and electron paramagnetic resonance spectroscopy. The solid phase transformation of magnetite to maghemite, as well as an increase in particle size were evidenced for the uncoated nanoparticles. The coated nanoparticles preserved their magnetite structure and magnetic properties. The influences of monomers and surfactant layers on interactions between the magnetic nanoparticles evidenced that the thickness of the polymer has a significant effect on magnetic properties.

Factors influencing the preparation of hollow polymer-graphene oxide microcapsules via Pickering miniemulsion polymerization

The synthesis of hollow, cross-linked polymer particles (‘capsules’) via Pickering miniemulsion polymerization using graphene oxide (GO) nanosheets as sole surfactant is reported. The influence of monomer, cross-linker and initiator type was studied, in addition to hydrophobe loading and initiator concentration. The desired hollow capsule morphology was shown to be strongly dependent on the choice of cross-linker; an aromatic crosslinker (divinylbenzene) consistently yielded hollow structures as determined by transmission electron microscopy, whereas ethylene glycol dimethacrylate typically resulted in polymer particles with a solid core. The use of an aromatic monomer with high propagation rate coefficient (benzyl methacrylate) and a strongly oil-soluble initiator, lauroyl peroxide, resulted in capsule synthesis with very high conversion (>85%) after 6 h. Surface area and pore analysis of the capsules established that while the capsules possessed a hollow interior, the shell was essentially non-porous. The potential of these materials towards novel nanocarbon-based materials was demonstrated via the preservation of colloidal stability and particle morphology after chemical reduction of GO, in addition to successful encapsulation of hydrophobic nanoparticles within the capsule core.

Polymeric microstructures and dielectric properties of polynorbornenes with 3,5-bis(trifluoromethyl)biphenyl side groups by ring-opening metathesis polymerization

exo-Polynorbornenes containing bis(trifluoromethyl)biphenyl side groups were synthesized by ring-opening metathesis polymerization using different Grubbs' catalysts, the microstructures of the polymer chains were established using NMR and IR spectroscopy. The influence of monomer and catalyst structures on chain microstructure was revealed and the correlation of properties with microstructure was investigated in detail. The exo-poly(N-3,5-bis(trifluoromethyl)biphenyl-norbornene-pyrrolidine) (exo-PTNP) and exo-poly(N-3,5-bis(trifluoromethyl)biphenyl-norbornene-dicarboximide) (exo-PTNDI) formed using Ru-I show a trans double bond bias of 67% and 83%, respectively, whereas the corresponding polymers formed using Ru-III have lower contents of trans double bond, 30% and 50%, respectively. Compared to the highly trans endo-PTNP formed using Ru-I, which is isotactic and has a dielectric constant of about 20, the endo-PTNP formed using Ru-III, the exo-PTNDIs and the exo-PTNPs formed using Ru-I and Ru-III all have different proportions of trans and cis double bonds, they are atactic and display relatively low dielectric constants, in the range 6 to 9. DSC measurements indicate some dependence of Tg, varying 161 to 221 °C, on tacticity and cis/trans ratios with higher trans contents tending towards higher Tg. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4786–4798

Influence of Monomer on the Transfer Properties of UV Waterless Offset Ink

Four kinds of monomers were chosen to prepare ink to research the effect of monomer on the ink transfer performance of UV waterless offset and improve the printing quality. The rheological properties such as viscosity, yield value, thixotropy and stickiness were tested and the ink transfer equation was built, the ink transfer rate was calculated and the effect of monomer on the ink transfer performance was analyzed through the ink transfer experiment. The research results show that the type of monomers has large impact on the rheological properties of UV waterless offset, so the ink transfer performances with different kinds of monomers are different. And the viscosity, thixotropy, yield value and stickiness of the ink with TPGDA and EOEOEA are little, the ink transfer performance is better.

Synthesis and Application of Water-Borne Nontoxic Emulsion from Wasted Polystyrene Foam

A new water-borne nontoxic emulsion of low cost was prepared by using wasted polystyrene foam as elementary component, butyl acrylate (BA), styrene (St) and vinyl acetate (VAc) as modifiers and solvents. Influences of monomers, compounded emulsifier on properties of emulsion were discussed. The optimum process conditions were as follows: m (PSF) : m (monomers) = 1 : 2 , m (sodium dodecyl sulphate) : m (OP-10) = 2 : 1 , m (VAc) : m (St) : m (BA) = 1 : 1 : 2 , and mass fraction of emulsifiers was 3.0 wt% accounting for the total mass of monomers. The synthetic latex with high adhesion strength, pollution-free, low cost and storage stability is applicable to prepare blast furnace slag unburnt bricks, respectively. The properties of the brick sample are better than that of MU 25 of GB 11945-89.

Oil Absorptive Polymers: Where Is the Future?

In the past decades, the oil absorptive polymers with three-dimensional cross-linked network have attracted the attention of scientists and engineers due to their potential use in oil pollution treatment. Till now, however, the published literature is quietly limited. Herein, the progress in oil absorptive polymers is firstly reviewed, with an emphasis on the influence of monomers on the absorption properties. At the end of this minireview, we made a discussion on the topic: Where is the future of oil absorptive polymers?

Influence of monomer and crosslinker molar ratio on the swelling behaviour of thermosensitive hydrogels

The synthesis of the poly(N-isopropylacrylamide-co-2-hydroxypropylmethacrylate) hydrogel along with the analysis of the residual monomers content and influence of monomer and crosslinker molar ratios on the swelling behaviour was investigated. Synthesis of thermosensitive hydrogel based on N-isopropylacrylamide was carried out with the molar ratios of 5, 10, 15 and 20 mol. % of monomer 2- hydroxypropyl-methacrylate, in the presence of ethylene glycol dimethacrylate as a crosslinker (1, 1.5, 2 and 3 mol. %) and 2,2'-azobis(2-methylpropionitril) as an initiator in acetone. The quantities of residual monomers in the synthesized copolymers were determined by HPLC method, ranging from 0.19 to 0.49 % for N-isopropylacrylamide and from 0.13 to 0.63 % for 2-hydroxypropyl-methacrylate, counting the amount of xerogel. The hydrogels swelling ratio depending on time at 20 and 40?C was examined. It was found that hydrogel with 5 mol. % 2-hydroxypropyl-methacrylate and 1 mol. % ethylene glycol dimethacrylate had the highest degree of swelling (? = 29.59) at 20?C, and that hydrogel with 20 mol. % 2-hydroxypropyl-methacrylate and 3 mol. % ethylene glycol dimethacrylate had the lowest swelling degree (? = 2.17) at 40?C.

One-pot synthesis of gold/poly(3,4-ethylendioxythiophene) nanocomposite

In this paper, we report the preparation of highly stable gold nanoparticles/poly(3,4-ethylendioxythiophene) nanocomposites by a one-pot chemical route in aqueous medium without surfactants to increase the solubility of the monomer (3,4-ethylendioxythiophene, EDOT) or to stabilize gold nanoparticles (Au NPs). The generation of the nanocomposite was followed by UV–Visible transmission spectroscopy combined with multivariate curve resolution alternating least squares analysis to deconvolute the individual spectra of the different species generated in the synthesis: oligomers, polymer and gold nanoparticles. The plasmon band observed at 530 nm during the synthesis step indicates the generation of gold nanoparticles. The influence of monomer and metal precursor concentration and their concentration ratios on Au NP size were analyzed. The electrochromic properties of the composite were investigated by UV–Visible absorption spectroelectrochemistry, being mainly related to polymer oxidation and reduction. The main difference observed is the hypsochromic shift of the polymer spectra due to the gold nanoparticles inside the polymer. Multicyclic spectroelectrochemical experiments evidence a high stability and adhesion of the nanocomposite.

The Study on the Influence of Monomer on the Printing Quality of UV Waterless Offset Ink

In order to observe the influence of monomer on the printing quality of UV waterless offset ink, ink samples with different monomer were made, and the main performance parameters such as viscosity, thixotropy, yield value, fluidity and stickiness were tested. Proofing by printability tester, and the printing qualities such as solid density, gloss, dot gain and print contrast were tested. Analyzing the influence of the difference of ink performance that caused by monomer on the printing quality of UV waterless ink. The results show that ink performances affect the printing quality directly. The differences of monomer’s structure and functionality have great effect on ink’s performance such as viscosity, thixotropy, yield value, fluidity and stickiness, and it can lead to the difference of printing quality such as solid density, gloss, dot gain, and print contrast.

Influence of Monomer on the Performance of UV Waterless Offset Ink

Waterless offset doesn't use dampening solution, so it has the advantage of color saturation that the water offset can not reach. Monomer is an important component of the UV waterless offset ink; it has great influence on the performances of ink. Ink samples were made separately by using different monomers. The flow curve, thixotropy crack index, surface tension, gloss, curing speed and other performance parameters of the ink samples were tested, and the influence of different kinds of monomer on the performance of ink was analysised. The results show that the viscosity of monomer affects the viscosity of ink sample directly; six monomers we used have good curing speed; the lowest surface tension can be got when using monomer with single functionality; and six ink samples have large thixotropy. The result of the compound EOEOEA, TPGDA and TMPTA is 0∶3∶7 by using the functionality design principle.

Solution polymerization of N‐vinylcaprolactam in 1,4‐dioxane. Kinetic dependence on temperature, monomer, and initiator concentrations

AbstractThe kinetics of the solution free radical polymerization of N‐vinylcaprolactam, in 1,4‐dioxane and under various polymerization conditions was studied. Azobisisobutyronitrile and 3‐mercaptopropionic acid were used as initiator and as chain transfer agent (CTA), respectively. The influence of monomer and initiator concentrations and polymerization temperature on the rate of polymerizations (Rp) was investigated. In general, high conversions were obtained. The order with respect to initiator was consistent with the classical kinetic rate equation, while the order with respect to the monomer was greater than unity. The overall activation energy of 53.6 kJ mol−1 was obtained in the temperature range 60–80 °C. The decreasing of the absolute molecular weights when increasing the CTA concentration was confirmed by GPC/SEC/LALS analyses. It was confirmed by UV‐visible analyses the effect of molecular weights on the lower critical solution temperature of the polymers. It was also verified that the addition of the CTA influenced the kinetic of the polymerizations. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Improvement of Surface Lubricity of Polymers and Metals by a Glow-Discharge Plasma Cross-Linking Process

A plasma cross-linking process was employed to improve the surface lubricity of different types of biomaterials, including stainless steel (SS), nitinol, polyethylene and nylon. To investigate the influence of monomers containing double bonds on top-layer cross-linking of poly(ethylene oxide) compound (PEOC), five different monomers, N-trimethylsilyl-allylamine (TMSAA), ethylene, propylene, allyl alcohol and ethane, were used in the study to produce a cross-linked coating layer on sample surfaces. Before the plasma cross-linking, samples underwent plasma treatment followed by wet chemical coating. The plasma treatment consists of plasma etching in NH3/O2, Tetramethylcyclo-tetrasiloxane (TMCTS) coating and TMSAA grafting. The wet coating process includes dip-coating in a solution of poly(oxyethylene)-compound bis(1-hydroxy-benzotriazolyl carbonate) (HPEOC), then dip-coating in a solution of PEOC. By application of plasma processing, HPEOC and PEOC wet coating to sample surfaces, the lubricity was increased by 83% compared to clean samples. The plasmas of TMSAA, ethylene, propylene and allyl alcohol, all containing a C=C double bond, produced a cross-linking layer on the PEOC surface. Consequently the surface lubricity was improved by 20% to 37% in comparison to no cross-linking. The favorable condition for plasma cross-linking was found to be high power and long time. Ethane plasma also reduced the pulling force although it has no double bond in the molecular structure, which indicated a thin plasma coating from saturated hydrocarbons deposited on HPEOC or PEOC surfaces could also cause cross-linking and improve lubricity. It was found that the TMSAA cross-linking also worked on HPEOC and HEPOC/PEOC, even though the prior plasma coating process was skipped.