Addition Of Benzoyl Peroxide Research Articles

Analisis Pengaruh Penambahan Magnesium Oksida terhadap Sifat Mekanis Bioadhesif Berbasis Kitosan-Karagenan

This study investigates the effect of magnesium oxide (MgO) as a filler in enhancing the bioadhesive properties of chitosan and carrageenan-based adhesives. The primary focus is on improving tensile strength, viscosity, solid content, and thermal properties. The results indicate that the addition of 0.75% w/v MgO significantly increased tensile strength from 9.76 kPa to 21.76 kPa and viscosity from 34.26 cP to 617 cP with a 0.5% w/v MgO addition. The solid content also increased from 9.81% to 13.19% with increased MgO concentration. The addition of benzoyl peroxide (BPO) reduced curing time, enhancing process efficiency. Scanning Electron Microscopy and Fourier Transform Infrared Spectroscopy confirmed improvements in structural and chemical stability, while Differential Scanning Calorimetry showed better curing efficiency. This study suggests MgO as a potential filler to improve mechanical properties and adhesion of bioadhesives, relevant for medical applications.

Polyurethane Membranes From Red Seaweeds For Ammonia Adsorption

Polyurethane (PU) membranes were prepared from red seaweed (Gracilaria sp.), castor oil, Toluene Diisocyanate (TDI), and added benzoyl peroxide (BPO) additive to improve membrane performance. The membrane is applied for the adsorption of ammonia in the solution. FT-IR analysis showed the presence of functional group N = C = O at a wavenumber of 2276 cm-1 and the O-H functional group at a wave number of 3373.50 cm-1, indicating the urethane group's formation has been formed during membrane polymerization. SEM images showed the morphological structure of the PU membrane, where the more open structure of the PU membrane by the addition of BPO. The DSC and TGA results showed the membrane's thermal stability with the addition of BPO. The PU membrane has an optimum contact time for ammonia uptake of 40 minutes. The adsorption isotherm of ammonia by the PU membrane follows the Freundlich isotherm model. The adsorption capacity of the PU membrane with the addition of BPO additives was 13.2 mg/g, which shows that the adsorption capacity of the PU-BPO membrane has a better performance than a membrane without the addition of the BPO. The PU-BPO membrane could be used as an alternative method of ammonia removal.

Influence of moisturizer containing licochalcone A, 1,2-decanediol, L-carnitine, and salicylic acid on facial skin lipidome among seborrhea participants.

A better understanding of skin lipidomics and its alteration under treatment administration might offer therapeutic solutions for seborrhea. To quantitatively and qualitatively explore the lipid-modifying effect of the moisturizer containing licochalcone A, 1,2-decanediol, L-carnitine, and salicylic acid (LDCS) in seborrhea participants with and without acne vulgaris (AV). We conducted an open-label explorative study on 20 seborrhea participants (10 AV and 10 non-AV). All participants applied LDCS for 8 weeks with the addition of benzoyl peroxide 2.5% gel and adapalene 0.1%/benzoyl peroxide 2.5% gel in AV. Skin surface lipid (SSL) assessments were performed biweekly, using Sebumeter® and lipid-absorbent Sebutapes® to collect forehead SSL for profile analysis by gas chromatography-mass spectrometry (GC-MS). SSL amount significantly decreased since week 2 in AV (p-value=0.0124) and week 6 in non-AV (p-value=0.0098), respectively. Twenty-two important SSLs were annotated from GC-MS analysis, comprising 19 free fatty acids, cholesterol, squalene, and glycerol. There was a significant reduction in 5 and 13 lipid components in AV and non-AV groups, respectively. LDCS, either alone or with topical acne treatment, demonstrated substantial sebusuppressive and lipid-modifying effects among seborrhea participants.

Carbon dot-based fluorescent and colorimetric sensor for sensitive and selective visual detection of benzoyl peroxide

Benzoyl peroxide (BPO) has been added in wheat flour because of its bleaching effect. However, the abnormal used BPO has caused increasing concern due to its strong oxidization capability which may have adverse effects on living organisms. Herein, we present a carbon dot (CD)-based fluorescent and colorimetric probe for visually, sensitively and selectively sensing BPO. The addition of BPO could quench the red fluorescence of CDs peaked at 622 and 677 nm, and decrease the absorbance at 613 nm, while increase the absorbance at 450 nm, resulting in a fluorescence turn-off and colorimetric spectral response. Moreover, the CDs had short response time of 10 min and high sensitivity towards BPO with a low limit of detection of 28 nmol/L. The applicability of the CDs in detecting BPO in wheat, noodle and starch samples was further demonstrated, and good recovery results were obtained.

Characterization of Heat-Polymerized Monomer Formulations for Dental Infiltrated Ceramic Networks

(1) Objectives: This work examined properties of dental monomer formulations of an aromatic dimethacylate (BisGMA), aliphatic urethane dimethacrylate (UDMA), and triethylene glycol dimethacrylate (TEGDMA). The monomers were combined in different ratio formulations and heat-polymerized containing the initiator benzoyl peroxide (BPO) specifically for the purpose of infiltration into polymer-infiltrated composite structures. (2) Methods: The monomers were combined in different weight ratios and underwent rheological analysis (viscosity and temperature dependence), degree of conversion, and mechanical properties (elastic modulus, hardness, fracture toughness). (3) Results: Rheological properties showed Newtonian behavior for monomers with a large dependence on temperature. The addition of BPO allowed for gelation in the range of 72.0–75.9 °C. Degree of conversion was found between 74% and 87% DC, unaffected by an increase of TEGDMA (up to 70 wt%). Elastic modulus, hardness, and fracture toughness were inversely proportional to an increase in TEGDMA. Elastic modulus and hardness were found slightly increased for UDMA versus BisGMA formulations, while fracture toughness ranged between 0.26 and 0.93 MPa·m0.5 for UDMA- and 0.18 and 0.68 MPa·m0.5 for BisGMA-based formulations. (4) Significance: Heat-polymerization allows for greater range of monomer formulations based on viscosity and degree of conversion when selecting for infiltrated composite structures. Therefore, selection should be based on mechanical properties. The measured data for fracture toughness combined with the reduced viscosity at higher UDMA:TEGDMA ratios favor such formulations over BisGMA:TEGDMA mixtures.

Constructing boronate-bridged core-satellite gold nanoassembly and its application in high sensitive colorimetric detection of benzoyl peroxide residues in food matrices

Here, a new designed core/satellite gold nanoprobe was developed for detecting trace mount of benzoyl peroxide (BPO) based on its deboronation. This gold nanoassembly (the BE-AuNPs12/65) was constructed via borate ester formation between large 4-mercaptophenylboronic acid (MPBA) modified AuNPs (the MPBA-AuNPs65, as cores) and small dopamine modified AuNPs (the DPA-AuNPs12, as satellites). Particularly, upon addition of BPO, it would trigger the deboronation for the BE-AuNPs12/65 probes accompanying with distinct color changes from blue, purple to wine red, which implied the disassembly of the core/satellite nanostructure after the breakage of carbon to boron chemical bond. By measuring the absorbance ratio at 665 nm and 545 nm, quantification of BPO was achieved in the range of 10.0–100.0 nmol/L, which could also be easily observed by naked eyes. The nanoprobe utilized a boronate deprotection mechanism and the LSPR properties of AuNPs to provide high selectivity for detecting BPO over similar ROS/RNS with the limit of detection as low as 7.2 nmol/L. The practical applicability of this assay was verified through successful determining BPO in flour samples, which demonstrated its great potentials in food safety field.

A Benzothiazole-based Ratiometric Fluorescent Probe for Benzoyl Peroxide and Its Applications for Living Cells Imaging

We present herein a novel ratiometric fluorescent probe (1) for benzoyl peroxide (BPO). Probe 1 was obtained by coupling the recognition unit of arylboronate to a benzothiazole-derived fluorophore. The probe solution is colorless and displays weak blue fluorescence at 460 nm. Upon the addition of BPO, the arylboronate substituent can be removed via oxidation and 1,4-elimination processes. The released fluorophore emits strong yellow-greenish fluorescence at 546 nm. The ratiometric response of the probe is highly selective and sensitive for BPO. The dynamic range was fitted over 1.0 - 75.0 μM with a detection limit of 0.26 μM. In addition, the probe was applied to quantitative detection of BPO in real samples of wheat flour and an antimicrobial agent. Cellular experiments further demonstrated that probe 1 can be effectively utilized for imaging BPO in living cells.

Blending modification of PBS/PLA and its enzymatic degradation

This study used benzoyl peroxide (BPO) as a cross-linking agent to modify the blends of poly(butylene succinate) (PBS) and poly(lactic acid) (PLA). The PBS/PLA blends with a ratio of 20/80 and added 1% BPO was chosen because of its favorable properties. The compatibility of PBS/PLA was improved after adding BPO. The addition of BPO also improved the crystallization and promoted the complete decomposition of PBS/PLA, respectively. The blends with BPO was degraded by proteinase K. The degradation rate of the blends reached 67% after 96 h degradation. The PLA was not degraded completely because of the crosslink between PBS and PLA.

The Effect of Benzoyl Peroxide and Divinyl Benzene on the Properties of Cross-Linked Recycled Polyolefin Blends

The effect of peroxide cross-linking on the properties and morphology of recycled polyethylene (PE)/polypropylene (PP) blends was characterized. The addition of benzoyl peroxide (BPO) decreased the melt flow rate (MFR) and increased the impact strength of the recycled polymer blends. Divinyl benzene (DVB) is often used as a cross-linking agent assistant. Compared with BPO modification, the addition of BPO together with DVB improved the cross-linking efficiency and further increased the impact strength of the recycled polymer blends. The effect of BPO content on the MFR and the mechanical properties was also studied with the DVB content fixed. However, chemical cross-linking slightly reduced the thermal stability of the polymer blends. The morphology of the modified and unmodified polymer blends showed that with the addition of BPO, with or without DVB, the compatibility of the PE/PP blends was improved, resulting in enhanced impact strength.

Development of the CNT Composite Conductive Resin Using Nano-Dispersion Process

We found that carbon-nanotubes(CNTs) can be nano-dispersed without specific processes. In this study, we tried to prepare conductive composite resins using the CNTs dispersion technique.1. IntroductionCNTs are very good to thermal conductivity, electrical conductivity, and molecular adsorption. It is expected when composite resin and CNTs, to become new functional composite materials. However, The CNTs would form aggregates with intermolecular forces of each other. Aggregated CNTs is not be able to exert the original characteristics. CNTs dispersion technology for acid treatment or the use of surfactants has been reported. However, suppression of re-aggregation is difficult in this technique. Serious problems of cost for manufacture of CNTs remain.We found an effective technique of dispersing nano-scale CNTs [1]. By mixing and stirring the CNTs and an aromatic compound having a specific structure (dispersion medium), CNTs to form a gel having a three-dimensionall network structure. This gel can maintain long time nano-dispersion of CNTs. This effective technique is very simple. We expect a decrease in production costs using this technique.In this study, we tried to prepare conductive composite resins using the CNTs dispersion techniques. A water-soluble resin and a polyester resin were examined. We used an aromatic and polyester resin. And, we used the polyvinyl alcohol (PVA) as a water-soluble resin, and water soluble dispersion medium. Prepared composites were studied by transmission electron microscopy (TEM). Volume resistivity was measured by using four-point probe method.2. ExperimentBenzoyl peroxide was used as curing agent of multi-walled carbon nanotubes (MWNTs). After addition of benzoyl peroxide and MWNTs (1.0-5.0 wt%) in the polyester resin, we repeated the ultrasonic irradiation and mixed with a centrifugal stirrer. In case of water-soluble resin, After addition of water-soluble dispersion medium and MWNTs (1.0-5.0 wt%) in the PVA resin, we repeated the ultrasonic irradiation and mixed with a stirrer. In either case, the resin became a black gel with fluidity. These gels were on the substrate, and dried or cured at room temperature.3. Result and DiscussedTEM images of the composite resin spread were shown in Fig.1. In either case, MWNTs formed network structures in three dimensions. It was succeeded in forming the persistent nano-dispersion of the MWNTs in the resin.Measurement of the volume resistivity of the composite films using four-point probe method is shown in Table I. In the case of polyester, was shown maximum conductivity (MWNTs content 5.0 wt%) 8.15×10-1 [Ω・cm]. In the case of PVA, was shown maximum conductivity (MWNTs content 2.5 wt%) 9.9 [Ω・cm]. It was found that MWNTs formed three-dimensional conductive network structures. For PVA, the addition of 3.0 wt% or more, CNTs brings poor workability so poor.4.

Effects of recombinant lipoxygenase on wheat flour, dough and bread properties

A purified recombinant lipoxygenase (ana-rLOX) was produced extracellularly in Bacillus subtilis and subsequently investigated for use in breadmaking. The variations in the properties of flour, dough and bread after treatment with the enzyme were studied. After adding ana-rLOX, whiteness (L*) of the wheat flour was improved and was similar to that achievable with the addition of benzoyl peroxide. For dough color, the L* of the ana-rLOX-treated sample was higher than that of benzoyl peroxide, and b* dropped sharply in the first 2.5h after mixing with the flour. Also, the reinforcement or strengthening effect of wheat dough treated with ana-rLOX was determined by dough rheology and scanning electron microscopy of gluten matrix. The textural and structural quality parameters of the enzyme-treated bread showed improved properties including crumb color, specific volume, resilience, chewiness, and hardness. Compared with the control, the enzyme-treated bread volume improved 16.8%, the loaf height increased 10.3%, and the specific volume increased by 18.2%. This is the first report of the application of recombinant LOX in breadmaking, and the results provide a basis for future breadmaking bioprocess technology applications of ana-rLOX.

Energetic-Assisted Scanning Thermal Lithography for Patterning Silver Nanoparticles in Polymer Films

Energetic-assisted scanning thermal lithography (SThL) was demonstrated with the addition of benzoyl peroxide (BPO) for patterning silver nanoparticles. SThL samples were prepared by spin-coating poly(methyl methacrylate) (PMMA) thin films preloaded with BPO and silver nitrate precursors. Localized thermal analysis via probe heating demonstrated that the BPO decomposition in the polymer film took place at the temperature of 80 °C. Above this temperature, the thermal probe initiated the decomposition of the peroxide, which resulted in the in situ discharge of exothermal energy to compensate the joule shortage and the rapid cooling in the SThL thin film samples. The additional joule energy thermally enhanced the synthesis of silver nanoparticles, which were patterned and embedded in the PMMA thin film. Surface plasmon resonance scattering of these silver nanoparticles was observed by dark-field optical microscopy, whereas the nanoparticle distribution was examined by transmission electron microscopy. Variations in the scanning probe temperatures and peroxide concentrations were carefully investigated to optimize the thermal lithography efficiency upon the addition of energetics.

Synthesis, Structure, Electrochemistry, and Electrochemiluminescence of Thienyltriazoles

Four blue-emitting thienyltriazoles with desired N and O coordination atoms were prepared in high yield via click chemistry for potential incorporation into metal complexes. Three of their crystal structures were determined by X-ray crystallography. The electrochemical properties, electronic structures of these thienyltriazoles, 1-4, and their correlations were studied using cyclic voltammetry and differential pulse voltammetry techniques along with density function theory (DFT) calculations. All of the compounds underwent irreversible redox reactions, leading to unstable electrogenerated radical cations and anions. Electrochemical gaps determined from the differences between first formal reduction and oxidation reactions were correlated to HOMO-LUMO energy gaps obtained from UV-vis spectroscopy and the DFT calculations as well as energies of excited states measured from photoluminescence spectroscopy. We observed weak electrochemiluminescence (ECL) from annihilation of these thienyltriazole radicals in acetonitrile containing 0.1 M tetra-n-butylammonium perchlorate as electrolyte. An enhancement in ECL efficiency ranging from 0.16 to 0.50% was observed upon addition of benzoyl peroxide as a coreactant in the above electrolyte solutions. The generation of excimers in solutions of 1-4 was observed as seen by the red-shift in ECL maxima relative to their corresponding photoluminescence peak wavelengths. Our work is of importance for the development of efficient blue-emitting fluorophores via click chemistry that could be potential luminophores in metal complexes.

Determination of benzoyl peroxide, as benzoic acid, in wheat flour by capillary electrophoresis compared with HPLC

In recent years, debate on the addition of benzoyl peroxide (BP) to wheat flour has increased in China. Medical studies have so far not confirmed that BP in wheat flour causes definite damage to the human body, but its main metabolite in the human body is benzoic acid. The addition of BP to wheat flour has been forbidden in China since 1 May 2011. It is therefore necessary to develop a suitable method to determine BP in wheat flour. A simple method using capillary electrophoresis (CE) was developed for determination of BP in wheat flour. BP was determined as benzoic acid after preceding reduction by potassium iodide. Separation was completed in less than 7 min with a running buffer of 10 mmol L⁻¹ sodium borate (pH 9.18), 4 s hydrodynamic injection, 25 kV separation voltage and UV detection at 228 nm. The method was validated in terms of linearity, sensitivity, detection limit, precision and accuracy. The detection limit was 0.29 µg mL⁻¹. The method was successfully applied to the determination of BP in wheat flour samples, with recoveries between 96.1% and 102.6%. The performance of the CE method was comparable, and the quantitative results were in good agreement with those using high-performance liquid chromatography (HPLC). Meanwhile the proposed CE method has the advantages of better resolution, shorter analysis time and lower cost, and would be a good alternative to HPLC for routine monitoring of BP amount in wheat flour.

Lignin reinforced rubber composites

AbstractLignin, a renewable waste material of pulp and paper industries, was analyzed through Fourier‐Transform Infrared Spectroscopy (FTIR) and found to be structurally similar to kraft lignin. Surface modification by addition of benzoyl peroxide and subsequent heating at 70°C caused generation of new functional groups in lignin. Efficacy of the crude lignin as well as that of the modified variety as a filler in nitrile rubber (NBR) has been evaluated. Rubber vulcanizates were analyzed for physico‐mechanical properties, oil and fuel resistance, and thermal stability, and compared with conventional fillers like phenolic resin and carbon black. Modified lignin has been found to produce superior elongation, hardness and compression set properties compared to phenolic resin but inferior to carbon black. Resistance to swelling, however, depends on the type of oil or fuel, and modified lignin always showed better properties than carbon black. Both thermo‐gravimetric analysis (TGA) and thermo‐mechanical analysis (TMA) showed highest thermal stability for the modified lignin followed by phenolic resin and carbon black.

Influence of polymerization initiator for base monomer on microwave curing of composite resin inlays.

Microwave polymerization was used to make composite resin inlays and the effect examined of the concentration of polymerization initiator for the base monomer. The monomers used were 2,2-bis [4-(3-methacriloxy-2-hydroxypropoxy) phenyl] propane (Bis-GMA) and triethyleneglycol dimethacrylate (TEGDMA). Bis-GMA and TEGDMA were mixed in a ratio of 6:4 by weight and were separated into five groups. To each group was added benzoyl peroxide (BPO) in the ratios of 0.1, 0.3, 0.5, 0.7 and 0.9 wt% as the polymerization initiator. These were used as the base monomers. The results showed that the degree of conversion of the cured sample increased with increasing concentration of BPO from 0.1 to 0.5 wt%, however there was no significant difference at 0.5, 0.7 and 0.9 wt% (P> 0.01). Compression strength, diametral tensile strength and the Knoop hardness showed a similar tendency as the degree of conversion. No significant difference was recorded in the Knoop hardness between the top and the bottom surfaces (P> 0.01), which suggested a uniform polymerization in the cured sample. Thus, microwave polymerization would be an efficacious method for making resin inlays with the addition of BPO to the base monomer (Bis-GMA:TEGDMA, 6:4). The maximum conversion was found at a concentration of 0.5 wt%.

Kinetics and Mechanism of Thermal Isomerisation of Aryl Alkanehydrazonates into N′,N′-Diarylhydrazides. Extension of a Recent Free Radical Analogue of the Chapman Rearrangement

Abstract A series of twelve aryl N-(p-nitrophenyl)alkanehydrazonates (I) have been prepared and their thermal rearrangement into N-acyl-N′,N′-diarylhydrazines (II) was investigated. The structures of I and II were derived from their elemental analyses and spectral properties. Hydrolysis of II afforded the corresponding N′,N′-diarylhydrazines. Kinetic experiments have shown that electron withdrawing substituents decrease the rate of the rearrangement whereas electron donating groups increase it. The rate of conversion of I into II was also increased by addition of benzoyl peroxide. A free radical mechanism was proposed to account for the results.

Studies on the Decomposition of Tocopherol and Oxidation Products of Edible Oils

In the previous papers, the authors reported that the decomposition of tocopherol in oxidative rancid oil increases more than those in non-rancid oil.In this paper, the influence on decomposition of tocopherol by oxidation products of oil was investigated. That is for the effect of free fatty acid and peroxide in oil on the decomposition of tocopherol. For examination the following kinds of lard were prepared, namely, without addition of dl-α-tocopherol; with addition of tocopherol by 0.2%; 0.2% tocopherol plus 0.32.3% fatty acid; 0.250.5mg% iron (some iron salts) added thereto; and 13% benzoyl peroxide added thereto; and they were heated at 180°C for 24hrs.The results obtained were as follows;1. Fatty acid and iron in oils did not promote the decomposition of tocoehhrol.2. The decomposition of tocopherol was apparently promoted by the peroxide of oil and the addition of benzoyl peroxide.

Simultaneous Syntheses of Aromatic Carboxylic Acids and Phenols. III

Formation of p-carboxybenzophenone by oxidation of p-methylbenzophenone with air in the presence of metal salt of organic acid has been investigated. Oxidation was carried out by blowing the air into the mixtuse of raw material and catalyst through the glass filter attached to the reaction tube of U-form under heating An example for suitable reaction condition is following; p-carboxybenzophenone is given in the yield of 47% by heating 100 parts of p-methylbenzophenone with 0.12 part of manganese naphth enate catalyst for 12 hrs at 210°c. under blow of air. Although the tests on addition of benzoyl peroxide or monochloroacetic acid as solvent has been done the yield was lower in each case.

塗料原料とする魚油塩素化物の製造に関する研究-X

A chlorination product of shark oil dissolved in carbontetrachloride with or without addition of benzoyl peroxide was subjected to irradiation with γ ray by 3.3×107 r in a sealed glass tube in order to obtain a product improved in the stability against heat. The irradiation proved, however, to have little effect on the melting point. The melting point of the product was raised to some extent only when the air in the sealed tube had been replaced by nitrogen before the irradiation, irrespective as to whether benzoyl peroxide had or had not been added to the sample.