Presence Of Monomer Research Articles

Investigation of potential rubber-degrading bacteria and genes involved.

COVID-19 pandemic has generated high demand for natural rubber gloves (NR) leading to crucial issues of rubber waste and waste management such as burning, dumping, stockpiling, discarding waste in landfills. Hence, rubber biodegradation by microorganisms is an alternative solution to the problem. The biodegradation method is environmentally friendly but normally extremely slow. Numerous microorganisms can degrade NR as a source of carbon and energy. In this study, Rhodococcus pyridinivorans KU1 was isolated from the consortium CK from previous study. The 40% rubber weight loss was detected after incubated for 2months. The bacterial colonization and cavities on the surface of rubber were identified using a scanning electron microscope (SEM). The result demonstrated the critical degradation of the rubber surface, indicating that bacteria can degrade rubber and use it as their sole carbon source. The result of whole-genome sequencing (WGS) revealed a gene that is 99.9% identical to lcp which is responsible for poly (cis-1,4-isoprene) degradation. The results from Meta16S rRNA sequencing showed that the microbial communities were slightly shifted during the 2-month degradation, depending on the presence of monomers or oligomers appeared during the degradation process. The majority of species were soil bacteria such as phylum Proteobacteria, Actinobacteria, and Firmicutes. Members of Pseudoxanthomonas seemed to be the dominant degraders throughout the degradation.

Synthesis of Bis(cyclic carbonates) from Epoxy Resin under Microwave Irradiation: The Structural Analysis and Evaluation of Thermal Properties.

This article describes the use of microwave irradiation in the synthesis of bis(cyclo carbonate) compounds (BCCs) in bulk (without solvent) from carbon dioxide capture using an epoxidized compound-a commercial epoxy resin-and compares this process to the conventional method. CO2 cycloaddition to epoxides is an ecological and efficient method for the formation of bis(cyclic carbonates). Moreover, the introduction of gas into the reaction mixture was carried out at atmospheric pressure with a controlled flow rate, which is advantageous from an economic point of view. Progressive structural changes and the presence of characteristic chemical groups were monitored using attenuated total reflectance infrared spectroscopy with Fourier transform. The obtained crude products were purified to obtain three fractions, which were subjected to detailed structural analysis using FT-IR and 13CNMR. The formation of the main product with two cyclic carbonates was confirmed. The presence of monomers, dimers and trimers in individual fractions as well as their thermal stability were determined, and the molecular masses in individual fractions were determined using gel permeation chromatography (GPC).

A sensitive Raman spectroscopy sensor for determination cardiac troponin I based on proteolytic peptide magnetic imprinting technology

This paper proposes a selective strategy for quantitative detecting cardiac troponin I (cTnI) in clinical serum samples by using Raman spectroscopy combined with magnetic molecularly imprinted polymers (MMIPs). The signature peptide was selected as a template for molecular imprinting due to its chemical stability and small molecular mass. MMIPs were synthetized with the signature peptide as template and methylacrylic acid as monomer in presence of vinyl-modified magnetic particles. MMIPs with high magnetic character and adsorption properties were able to be stained by Coomassie Brilliant Blue G-250 after the target template was specifically captured, which showing a characteristic absorption peak at Raman shift 1610 cm−1. The Raman signal intensity at 1610 cm−1 showed a linear relationship in the 0.01 to 100 ng·mL−1 concentration range. The recovery of cTnI in serum were 92.7–111.2 % with relative standard deviation in the range of 2.51 % to 8.52 %. This paper has important practical application for preliminary rapid detection of cTnI in clinical serum samples.

Dynamic transformation of bio-inspired single-chain nanoparticles at interfaces.

The interfacial behavior of macromolecules dictates their intermolecular interactions, which can impact the processing and application of polymers for pharmaceutical and synthetic use. Using molecular dynamics simulations, we observe the evolution of a random heteropolymer in the presence of liquid-liquid interfaces. The system of interest forms single-chain nanoparticles through hydrophobic collapse in water, lacking permanent crosslinks and making their morphology mutable in new environments. Complex amphiphilic polymers are shown to be capable of stabilizing high interfacial tension water-hexane interfaces, often unfolding to maximize surface coverage. Despite drastic changes to polymer conformation, monomer presence in the water phase is generally maintained and most changes are due to increased hydrophobic solvent exposure toward the oil phase. These results are then compared to the behavior at the water-graphene interface, where the macromolecules adsorb but do not remodel. The polymer's behavior is shown to depend significantly on both its own amphiphilic character and the deformability of the interface.

In situ composite of graphene oxide in polyacrylamide to enhance strength of hydrogel with polyethyleneimine as crosslinker

Polymer gel was widely used in the petroleum industry for water shutoffs to enhance oil recovery or for plugging to control lost circulation events. By free radical polymerization of acrylamide monomers in presence of graphene oxide (GO) nano sheets, polyacrylamide graphene oxide composite (PAMGO) was synthesized and used to prepare high strength hydrogel with polyethyleneimine (PEI) as crosslinker. The gelation time of gel was determined with viscosity test and gel strength was evaluated with rheological measurements and sand pack breakthrough pressure test. ATR-FTIR and SEM test was adopted to characterize the structure and morphology of the gel. The results showed that compared to polyacrylamide (PAM) gel, gelation time of composite gel decreased while gel elasticity modulus increased. The breakthrough pressure of composite gel is 21.71 MPa and increased by 20.71%. However, the mixing of graphene oxide in PAM gelling solution causes detrimental effects on gel strength and the breakthrough pressure of the mixture gel is only 3.72 MPa. The ATR-FTIR spectroscopy confirmed that the type of hydrogen bonding in the composite gel was different from that in the PAM GO mixture gel. The hydrogen bonding between N, O in composite and hydrogen atom on GO in the composite gel can enhance gel strength with reducing porosity and more crosslinking density of gel while the hydrogen bonding for H of NH2 in PAM with oxygen atom on GO in the mixture gel can occupy the crosslinking points, resulting in less crosslinking density and gel strength.

Repairable, Recyclable, and Regenerable Macrocycle Organic Polymer†

Comprehensive SummaryCovalent/metal organic frameworks are highly attractive due to their tunable structure and properties, and broad applications in multiple fields. However, they still suffer from numbers of drawbacks including low solubility, harsh synthesis and fabrication, and low mechanical flexibility. Herein, we report a new organic framework consisting of macrocycles and organic frames in its periodic structure, and denote it as macrocycle organic polymer (MOP). The size‐tunable macrocycles containing peripheral furan units are synthesized by anionic ring‐opening polymerization, which undergo a reversible Diels‐Alde reaction with bismaleimide to generate/degrade MOPs at given temperatures. Relying on above features, MOPs exhibit excellent flexibility, healable ability and recycle ability. Interestingly, owing to the “living” nature of anionic ring‐opening polymerization, MOPs can self‐grow into bigger sizes in the presence of monomer and catalysis, analogs to the living creatures. Moreover, their high porosity and rich thioether structure enable them as good metal ion absorbers and promising applications in wearable electronics.

PENGARUH LAMA STERILISASI TERHADAP MUTU SAYUR LEBUI KALENG

Sayur lebui or pigeon pea soup is a traditional Lombok that has been used plastic as a packaging. Plastic packaging has a weakness in the presence of monomers and small molecules that will migrate into food, making the shelf life relatively low with high microbial contamination. One technology that can be used to overcome this is canning technology. The most important process in canning is the sterilization process. This study aims to determine the effect of sterilization time on the quality of canned lebui vegetables. The method used in this study was an experimental method carried out in the laboratory. The design used in this study was a randomized block design (RBD) with a single factor experiment, namely the duration of sterilization with 6 treatments, namely 0 minute, 3 minutes, 6 minutes, 9 minutes, 12 minutes, 15 minutes. Analyzed using ANOVA with a significant level of 5% using Co-stat software. The difference data was tested using Honestly Significant Differences (HSD) Test. The prolonged sterilization treatment of pigeon pea soup had a significant effect on the pH value, antioxidant activity, color, organoleptic parameters of texture, color and appearance, but had no significant effect on the organoleptic parameters of aroma and taste. Based on chemical, physical and organoleptic parameters, sterilization time of 9 minutes is recommended to produce the best pigeon pea soup with an antioxidant activity value of 86.05%, a pH value of 5.03, an oHue value of 45.27 (red) and hedonic organoleptic quality and a score that is still acceptable.

Functionalization of Polylactide with Multiple Tetraphenyethane Inifer Groups to Form PLA Block Copolymers with Vinyl Monomers

In the present contribution, a new strategy for preparing block copolymers of polylactide (PLA), a bio-derived polymer of increasing importance, is described. The method should lead to multiblock copolymers of lactide with vinyl monomers (VM), i.e., monomers that polymerize according to different mechanisms, and is based on the introduction of multiple "inifer" (INItiator/transFER agent) groups into PLA's structure. As an "inifer" group, tetraphenylethane (TPE, known to easily thermally dissociate to radicals) was incorporated into PLA chains using diisocyanate. PLA that contained TPE groups (PLA-PU) was characterized, and its ability to form initiating radicals was demonstrated by ESR measurements. PLA-PU was used as a "macroinifer" for the polymerization of acrylonitrile and styrene upon moderate heating (85 °C) of the PLA-PU in the presence of monomers. The formation of block copolymers PLA/PVM was confirmed by 1H NMR, DOSY NMR, and FTIR spectroscopies and the SEC method. The prepared copolymers showed only one glass transition in DSC curves with Tg values higher than those of PLA-PU.

Fe‐based catalyst with diphenylphosphite as donor for stereopolymerization of butadiene, isoprene, and myrcene

AbstractIron catalyst has been encountered with low activity and stereoselectivity sensitive to the operational conditions for diene polymerization. In this study, diphenylphosphite has been proved as an efficient donor in iron‐based tertiary catalyst for butadiene, isoprene and myrcene stereopolymerizations. Thermal robustness of active species has been demonstrated as the high activity and 1,2 stereoselectivity are survived in a wide temperature scope ranging from 5°C to 80°C. The resultant polybutadienes are found to have 1,2 incorporation up to 92.8% with syndiotactic conformation (rrrr: 95.1%), and more than 65% of irregular 3,4 enchainments are generated for polyisoprene and polymyrcene. The active species are formed preferably following addition sequence of iron compound, donor and activator in the presence of monomer. The development of this highly active and stable catalyst combining cost‐efficient components and mild operation parameters could provide accessible catalyst recipe to produce new types of polydienes.

Colloidal synthesis of CdTe nanoplatelets using various cadmium precursors

Two-dimensional (2D) CdTe nanoplatelets were synthesized using cadmium propionate, acetate and myristate precursors. Growth of nanoplatelets within the temperature range of 180–250 °C was monitored with optical absorption, PL spectroscopy and transmission electron microscopy. Continuous growth of NPLs was observed for hydrophobic propionate and myristate precursors at low temperatures, while in the presence of cadmium acetate Ostwald ripening occurs at high growth temperature. It is shown that zinc blende CdTe nanoplatelets with (00l) truncation axis grow by lateral expansion with oriented attachment mechanism. The presence of monomers is considered of major importance for oriented attachment. The growth conditions and duration time were optimized to provide homogeneous CdTe nanoplates.

Fabrication and mechanical properties of knitted dissimilar polymeric materials with movable cross-links

Movable cross-network elastomer with knitting polymers (KP elastomer) were obtained by bulk polymerization of main chain monomers in presence of host polymer. The two design strategies successfully improve the toughness and stiffness of the KP elastomers.

Magnetic molecularly imprinted polymer for the simultaneous selective extraction of phenoxy acid herbicides from environmental water samples

A selective magnetic molecularly imprinted polymer (MMIP) was synthetized with 4-chloro-2-methylphenoxyacetic acid as template and 4-vinylpiridine as monomer in presence of vinylized magnetite nanoparticles. Scanning electron microscopy, nitrogen adsorption-desorption isotherms, Fourier transform infrared spectrometry and vibrating sample magnetometry were applied to characterize the resulting material. The synthesized MMIP was applied as sorbent in magnetic molecularly imprinted solid-phase extraction (MMISPE) for selective extraction of a mixture of the five herbicides 4-chloro-2-methylphenoxyacetic acid (MCPA), 4-(4-chloro-2-methylphenoxy)butyric acid (MCPB), mecoprop (MCPP), fenoxaprop (FEN) and haloxyfop (HAL). Several parameters affecting the extraction conditions were optimized to achieve the best extraction performance. The best MMISPE combined with HPLC-DAD gave detection and quantification limits between 0.33 and 0.71 μg L−1 and 1.1–2.4 μg L−1, respectively, were obtained. The precision of the whole method provided RSD values below 7.3%, and the accuracy was demonstrated by the analysis of several water samples of different origins, with recoveries ranged from 77 to 98%. Moreover, a remarkable re-usability of the MMIP sorbent, more than 65 uses without losses in extraction capacity, was obtained.

Raman and DFT investigations on the interaction of binary liquid mixtures of acetone with polar and non-polar solvents

Raman measurements and DFT calculations were performed on binary liquid mixtures of acetone with methanol, Isopropyl alcohol (IPA) and carbon tetra chloride (CT). The deconvoluted Raman spectrum of carbonyl stretching mode of acetone indicates the presence of monomer and dimer structures of acetone in liquid. At higher dilution of acetone with methanol and isopropyl alcohol, there is a splitting of carbonyl stretching mode of acetone. This shows the breaking of self association of acetone at higher dilution. Acetone with carbon tetrachloride binary liquid mixture shows a blue shift in Raman spectrum at dilution. Also the interaction energies were calculated to explain the predominant interaction between dimer structure of acetone with methanol, IPA and CT. The Kirkwood polarization was calculated to explain the interaction of acetone molecules in the methanol, IPA and CT environment.

The Effect of Electrolyte Ingredients on Electrolyte-Electrode Interface in Electrocoating: A Comparative Study

In this study, CFs were coated electrochemically with three different monomers (An, EDOT or Py) in different condition such as electrolyte (BA, H 2 S0 4 or NaClO 4 ), solvent (H 2 O as inorganic medium or ACN as organic medium), in presence of foreign material (EBC) and coating method (constant potential and cyclic voltammetry as controlled potential). Obtained CFs were compared with regard to electrical and capacitive and morphological features. In CPE the current flown in system was changed in certain values for each monomer in presence of EBC. But this changing was more for Py than that for the other. In CV experiments, the oxidation potential was increased for PAn and PEDOT when it was decreased for Py. Imax values were changed for each polymer and conditions. According to Randles-Sevcik equation, the electrocoating redox processes in BA-H 2 O were not controlled by diffusion under this conditions. But, all the redox processes carried out in NaClO 4 -ACN electrolyte solution were controlled by diffusion for each polymer coated CFs. In presence of EBC it could be concluded that redox process was controlled by diffusion in BA-H 2 O for PAn and in NaClO 4 -ACN for PEDOT. In presence of 1.8 % EBC. The C DL value was decreased to 4 µF from 6 µF; to 0.7 µF from 1.5 µF; to 1 µF from 3 µF in BA-H 2 O for Pan, PEDOT and PPy respectively. But, it was increased to 11.5 µF from 10.4 µF in NaClO 4 -ACN for PEDOT. Phase angle was in the same trend. The texture coatings were more compact in the presence of EBC in electrolyte solution than that of the absence of EBC for PPy coated CF. The relationship of between the radius of coating and the C DL of the coated CF was proportional. Thus, it may be concluded that the C DL and radius of coating were affected with the presence of different material/compound in electrolyte solution. Keywords: PAn, PEDOT, PPy, presence of EBC, comparison, impedance, texture coating. DOI: 10.7176/CMR/13-3-05 Publication date: November 30 th 2021

Au nanoparticle modified GO/PEDOT-PSS based immunosensor probes for sensitive and selective detection of serum immunoglobulin g (IgG)

In the present work, we have developed a cost effective, label free, sensitive and selective, capacitive immunosensor based on composites of conducting polymer PEDOT-PSS, graphene oxide (GO) and gold nanoparticles (AuNPs) deposited on ITO electrode. The composite electrode was fabricated by performing electrochemical polymerization of EDOT monomer in presence of PSS, keeping GO as dopant covered with chemically inert AuNPs. The composite electrode has been studied by using various structural characterization techniques to understand the improved composition and morphology. To investigate the electrochemical properties of modified electrodes Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) were employed. New redox peaks and peak shifts in the CV of PEDOT-PSS indicated incorporation of GO and Au. Impedance data for all three electrodes was analyzed using a common equivalent circuit and suggested both kinetically and diffusion controlled processes. Specific interaction of antibody-analyte for all three electrodes was monitored directly via transient capacitance measurements at low and medium frequencies. Results showed that the AuNP/GO/PEDOT-PSS electrode is stronger mechanically and highly sensitive suggesting flexible sensor applications. With transient capacitance measurements, the proposed immunosensor exhibits high sensitivity in the range of 9–363 ng/mL with a detection limit of 49 ng/mL.

Visible light-induced cross-linking of unmodified gelatin with PEGDA for DLP-3D printable hydrogels

The 3D printability of cold-water fish gelatin used as co-initiating species for the crosslinking of PEGDA monomers in presence of camphorquinone (through a Norrish II reaction) is evaluated. The 3D digital light processing leads to the creation of biocompatible printed structures able to support cell viability and proliferation.

Visible light-induced crosslinking of unmodified gelatin with PEGDA for DLP-3D printable hydrogels

The 3D printability of cold-water fish gelatin used as co-initiating species for the crosslinking of PEGDA monomers in presence of camphorquinone (through a Norrish II reaction) is evaluated. The 3D digital light processing (DLP) leads to the creation of biocompatible printed structures able to support cell viability and proliferation.

Design and application of molecularly imprinted Polypyrrole/Platinum nanoparticles modified platinum sensor for the electrochemical detection of Vardenafil

Vardenafil (VRL) is one of the highly potent PDE-5 inhibitor pharmaceutical compounds used for treatment of erectile dysfunction. In this work, the sensor was fabricated via electropolymerization of pyrrole (Py) as a functional monomer in presence of VRL on a platinum electrode (PtE) modified with electrodeposited platinum nanoparticles (PtNPs) followed by electrochemical overoxidation to yield overoxidized polypyrrole (OPPy). During the sensor’s fabrication, seven factors need to be optimized including, pyrrole concentration (PyConc.) (mM), VRL concentration (VRLconc.) (mM), no of polymerization cycles (no. of cycles), incubation time (t.rebind) (min), pH of the incubation (pH), accumulation time (t.acc) (s) and accumulation potential (Pot.acc) (V). That is why fractional factorial design was first applied for screening the most significant factors followed by central composite design (CCD) optimization in order to have a correlative overview of the different interactions between these variables at the same time, unlike the traditional approach involving changing one factor at a time. Stepwise construction of the sensor was characterized electrochemically using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) and topographically using Scanning electron microscopy (SEM). The sensor showed linearity over the range of concentrations (1 × 10-12 M – 5 × 10-8 M) using differential pulse voltammetry (DPV) and EIS with a significantly low limit of detections 2 × 10-13 M and 0.9 × 10-13 M (S/N = 3), respectively under optimum conditions. The fabricated (OPPy/PtNPs/PtE) sensor was successfully applied to determine VRL in two pharmaceutical formulations, spiked urine and serum samples with percent recoveries between (98.9 % and 102.2 %) ± SD (±0.02 and ± 0.48).

Molecularly Imprinted Polymers Combined with Electrochemical Sensors for Food Contaminants Analysis.

Detection of relevant contaminants using screening approaches is a key issue to ensure food safety and respect for the regulatory limits established. Electrochemical sensors present several advantages such as rapidity; ease of use; possibility of on-site analysis and low cost. The lack of selectivity for electrochemical sensors working in complex samples as food may be overcome by coupling them with molecularly imprinted polymers (MIPs). MIPs are synthetic materials that mimic biological receptors and are produced by the polymerization of functional monomers in presence of a target analyte. This paper critically reviews and discusses the recent progress in MIP-based electrochemical sensors for food safety. A brief introduction on MIPs and electrochemical sensors is given; followed by a discussion of the recent achievements for various MIPs-based electrochemical sensors for food contaminants analysis. Both electropolymerization and chemical synthesis of MIP-based electrochemical sensing are discussed as well as the relevant applications of MIPs used in sample preparation and then coupled to electrochemical analysis. Future perspectives and challenges have been eventually given.

Synthesis and characterization of novel PES/GO-g-PSS mixed matrix membranes with outstanding antifouling and dye rejection properties

In this study, a novel mixed matrix ultrafiltration membrane based on polyethersulfone (PES) was prepared by embedding graphene oxide-g-polystyrene sulfonate (GO-g-PSS) nanoplates into the polymer matrix by using the phase inversion method. The GO-g-PSS nanoplates were synthesized by using the ATRP method, based on which the ATRP initiator was first grafted onto pre-modified graphene oxide (GO-NH2), and subsequently, the polymerization process was carried out in the presence of monomers. Water contact angle and porosity measurements were both employed for characterization of the prepared membranes. Additionally, the structure and morphology of all the prepared membranes were evaluated by using scanning electron microscopy (SEM) and atomic force microscopy (AFM). It was also found that, using these nanoparticles, water flux, porosity and hydrophilicity of membranes remarkably increased. Moreover, the more the modified GO loading amount increased, the more the roughness of the prepared membranes increased. The performance of all the prepared membranes was also investigated in terms of rejection, flux recovery and fouling parameters. Accordingly, the retention of two dyes and bovine serum albumin (BSA) molecules was tested, by which the effects of mean pore size, dimensions of permeated molecules and hydrophilicity of the membrane surface were analyzed. It was demonstrated by the fouling test that the 0.75wt% GO-g-PSS/PES membrane sample could provide the highest FRR value (89.9%) and the lowest irreversible fouling resistance (Rir) value (10.1%).