Phenolic Polymers Research Articles

Increasing and eliminating the (Fecal coliforms, thermotolerant coliform and fecal streptococcus) bacteria by resin of the poly (para carboxy acid phenol-d-Glucose) to clean up waste water

In this research paper we represent a novel synthetic antibacterial phenolic polymer (pAP-DG) containing carboxylic acid group in para position. The study of poly (p-carboxylic acid phenol d-Glucose) as an antibacterial resin was focused on the development of antimicrobial polymers to clean up the water of pathogenic bacteria. The polycondensation reaction was realized between p-carboxy acid phenol (pAP) and d-Glucose (DG) as monomers; using sulfuric acid as homogeneous catalyst.The obtained polymer was used via fecal coliform (TC), thermotolerant coliforms (CTT) and fecal streptococci (ST) bacteria to evaluate the water quality. The antibacterial activity of the synthesized resin was carried out by the contact method so the capacity of this resin was confirmed. In general, the polymer has a good antimicrobial activity against the microorganisms tested; the resulting polymer was characterized by various spectroscopy methods such as: 1H NMR, 13C NMR, DSC and FTIR and a mechanism has been proposed for this polycondensation reaction.

Enhanced mechanical strength of polyethylene-based lignocellulosic-plastic composites by cellulose fibers

Wood flour (WF) of poplar, acid hydrolysis residue (AHR) of corn cob from xylose production, and cellulose fibers (CF) from bleached eucalyptus pulp were compared as functional fillers of lignocellulosic-plastic composites (LPC) in terms of tensile strength and thermal stability. WF showed a negative effect on tensile strength of LPC. AHR-filled LPC at 10% of filling level exhibited an improvement by 8.9%, whereas higher filling level led to a decrease of tensile strength due to poor interfacial compatibility, as revealed by SEM analysis. Remarkably, tensile strength achieved a maximum of 25.8 MPa for CF-filled LPC at 2.5% of filling level, which was an approximately 76.7% improvement compared to the control. Dependence of LPC thermal stability on chemical compositions of fillers was revealed. WF-filled LPC showed a lower onset decomposition temperature compared to the control due to the presence of xylan, while thermal stability of AHR-filled LPC was enhanced due to the presence of cross-linked phenolic polymer lignin.

Mass Spectrometry Determination of Fining-Related Allergen Proteins in Chilean Wines

Casein (milk powder) and ovalbumin (egg white powder) are often used as wine fining agents with the objective to promote interactions with undesirable compounds, e.g., polymeric phenols. This kind of proteins may trigger allergic reactions in susceptible individuals; therefore, their occurrence in wines could become a human health risk, moreover when their presence is not reported. The objective of this work was to establish a mass spectrometry method to determine casein and ovalbumin in Chilean wines. To the best of our knowledge, the present work reports for the first time the presence of these proteins in Chilean wines. Proteins were extracted combining the use of ultrafiltration membranes and protein precipitation with organic solvents. Thereafter, proteins were digested with trypsin during 7 h with a 1:10 enzyme protein ratio. Chromatographic separation was carried out on a Kinetex XB C18 (100 × 4.6 mm, 2.6 μm) column set at 35 °C using an acidified (0.1% v/v formic acid) mobile phase composed of ultrapure water (A) and acetonitrile (B). For a highly selective evaluation, quantification was carried out by mass spectrometry applying multiple reaction monitoring (MRM). Validation was established according to the International Conference Harmonization guidelines. Calibration data (n = 6) fitted a linear regression model with determination coefficients (R2) higher than 0.99. Repeatability (n = 6) and intermediate precision (n = 3) showed RSD values ≤ 1.36% and ≤ 1.53%, respectively. Recovery (n = 3) at three levels ranged from 86.40 to 106.98%. Detection and quantification limits ranged from 4.70 to 8.50 μg L−1 and 10 to 20 μg L−1, respectively. Twenty Chilean wine samples were analyzed; 18 samples showed quantifiable levels, from which three samples presented a total casein and ovalbumin concentration (0.24–0.26 mg L−1) closer or higher to the European limit for mandatory labeling (0.25 mg L−1).

Development of Environmentally Friendly Brake Lining Material

Materials commonly used as brake pads are asbestos and alloys, but this material is very dangerous to the environment and health. This research was developed to answer these problems, namely to look for alternative brake pads that have good mechanical and structural properties and are environmentally friendly. Brake lining pads material is made from hybrid composite reinforced basalt, shells, alumina and bound using phenolic resin polymer (PR-51510i). This brake pads material is produced through a sintering process with an emphasis of 2000 kg for 30 minutes at a fixed temperature of 160°C. This hybrid composite is made in as many as five variations, each of which is tested for wear resistance using a pin on disc test based on ASTM G 99-95a standards, while destilled water absorption test was based on ASTM D 570-98. The greatest wear rate is 0.000090 g/cm, which is still lower than wear rate of asbestos brake pad materials, and the highest destilled water absorption of the brake pads specimens obtained was 0.041558 still lower than the destilled water absorption of asbestos brake pads.

Naturally-Derived Amphiphilic Polystyrenes Prepared by Aqueous Controlled/Living Cationic Polymerization and Copolymerization of Vinylguaiacol with R⁻OH/BF₃·OEt₂.

In this study, we investigated direct-controlled/living cationic polymerization and copolymerization of 4-vinylguaiacol (4VG), i.e., 4-hydroxy-3-methoxystyrene, which can be derived from naturally-occurring ferulic acid, to develop novel bio-based amphiphilic polystyrenes with phenol functions. The controlled/living cationic polymerization of 4VG was achieved using the R–OH/BF3·OEt2 initiating system, which is effective for the controlled/living polymerization of petroleum-derived 4-vinylphenol in the presence of a large amount of water via reversible activation of terminal C–OH bond catalyzed by BF3·OEt2, to result in the polymers with controlled molecular weights and narrow molecular weight distributions. The random or block copolymerization of 4VG was also examined using p-methoxystyrene (pMOS) as a comonomer with an aqueous initiating system to tune the amphiphilic nature of the 4VG-derived phenolic polymers. The obtained polymer can be expected not only to be used as a novel styrenic bio-based polymer but also as a material with amphiphilic nature for some applications.

Metabolic stimulation of phenolic biosynthesis and antioxidant enzyme response in dark germinated barley (Hordeum vulgare L.) sprouts using bioprocessed elicitors.

Sprouting and seed elicitor treatments stimulate the biosynthesis of health relevant phenolic bioactives in plants partly by upregulating proline-associated pentose phosphate pathway (PAPPP). This study investigated the upregulation of PAPPP-linked and antioxidant enzyme associated metabolic responses in elicitor-treated barley (Hordeum vulgare L.) sprouts previously established with stimulation of health relevant phenolic bioactives. Barley seeds were treated with bioprocessed elicitors marine protein hydrolysates (GroPro®, GP) and soluble chitosan oligosaccharide and germinated under dark conditions. Upregulation of PAPPP and subsequent stimulation of phenolic biosynthesis and antioxidant enzyme responses were monitored at day 2, 4, and 6 of sprouting. High PAPPP-linked antioxidant enzyme responses were observed at early stages of germination with selected doses of GP treatments, especially in cv. Pinnacle. Total soluble phenolic content remained at higher level, while guaiacol peroxidase activity increased over the course of sprouting indicating increased phenolic polymerization to support structural needs of sprouts.

Thermally and mechanically reliable photoresist for redistribution layer for advanced packaging

A photoresist with high mechanical and thermal reliability is required for redistribution layer (RDL) formation to improve integration density and realize thinner packaging for semiconductor industries. We report on a photoresist made from a mixture of a carboxyl group containing polyimide–phenol polymer and a slide-ring polymer. The photoresist showed high toughness, low coefficient of thermal expansion, and excellent long-term thermal stability, keeping its lithography properties, such as 8-μm-diameter via-hole having the depth of 15 μm, and 200°C to 220°C low-temperature curability. This resist will help panel-level-package technology by improving its reliability, and also integrate RDL for automotive packaging.

Investigating the relationship between grape cell wall polysaccharide composition and the extractability of phenolic compounds into Shiraz wines. Part I: Vintage and ripeness effects.

Phenolic compounds play an important role in colour stability and sensory properties of red wine. This study evaluated berry skin cell wall composition and how this influences grape and wine phenolics at different ripeness levels (21°Brix, 23°Brix, and 25°Brix) over two consecutive vintages. The vintage effect was highly significant, especially in the pectin fraction of the grape cell walls and affected the concentrations of certain phenolics extracted. The climatic variance between the seasons might have influenced the differences observed in the grape cell wall compositions. Firstly, a higher grape and wine phenolic content, especially in polymeric phenols, was found in 2015 wines. Additionally, grape berry cell walls, especially at the earliest stages of ripening, were found to be more intact in 2015 than in 2016. Thus, a possible relationship was found between the degree of berry intactness, especially for pectin-rich components, and the corresponding phenolic extractability during the winemaking.

CAD1 and CCR2 protein complex formation in monolignol biosynthesis in Populus trichocarpa.

Lignin is the major phenolic polymer in plant secondary cell walls and is polymerized from monomeric subunits, the monolignols. Eleven enzyme families are implicated in monolignol biosynthesis. Here, we studied the functions of members of the cinnamyl alcohol dehydrogenase (CAD) and cinnamoyl-CoA reductase (CCR) families in wood formation in Populus trichocarpa, including the regulatory effects of their transcripts and protein activities on monolignol biosynthesis. Enzyme activity assays from stem-differentiating xylem (SDX) proteins showed that RNAi suppression of PtrCAD1 in P.trichocarpa transgenics caused a reduction in SDX CCR activity. RNAi suppression of PtrCCR2, the only CCR member highly expressed in SDX, caused a reciprocal reduction in SDX protein CAD activities. The enzyme assays of mixed and coexpressed recombinant proteins supported physical interactions between PtrCAD1 and PtrCCR2. Biomolecular fluorescence complementation and pull-down/co-immunoprecipitation experiments supported a hypothesis of PtrCAD1/PtrCCR2 heterodimer formation. These results provide evidence for the formation of PtrCAD1/PtrCCR2 protein complexes in monolignol biosynthesis inplanta.

Patterned Deposition of Xylan and Lignin is Independent from that of the Secondary Wall Cellulose of Arabidopsis Xylem Vessels.

The secondary cell wall (SCW) of xylem vessel cells provides rigidity and strength that enables efficient water conduction throughout the plant. To gain insight into SCW deposition, we mutagenized Arabidopsis thaliana VASCULAR-RELATED NAC-DOMAIN7-inducible plant lines, in which ectopic protoxylem vessel cell differentiation is synchronously induced. The baculites mutant was isolated based on the absence of helical SCW patterns in ectopically-induced protoxylem vessel cells, and mature baculites plants exhibited an irregular xylem (irx) mutant phenotype in mature plants. A single nucleic acid substitution in the CELLULOSE SYNTHASE SUBUNIT 7 (CESA7) gene in baculites was identified: while the mutation was predicted to produce a C-terminal truncated protein, immunoblot analysis revealed that cesa7bac mutation results in loss of production of CESA7 proteins, indicating that baculites is a novel cesa7 loss-of-function mutant. In cesa7bac , despite a lack of patterned cellulose deposition, the helically-patterned deposition of other SCW components, such as the hemicellulose xylan and the phenolic polymer lignin, was not affected. Similar phenotypes were found in another point mutation mutant cesa7mur10-2 , and an established knock-out mutant, cesa7irx3-4 Taken together, we propose that the spatio-temporal deposition of different SCW components, such as xylan and lignin, is not dependent on cellulose patterning.

Genetic architecture underlying the lignin biosynthesis pathway involves noncoding RNAs and transcription factors for growth and wood properties in Populus.

SummaryLignin provides structural support in perennial woody plants and is a complex phenolic polymer derived from phenylpropanoid pathway. Lignin biosynthesis is regulated by coordinated networks involving transcription factors (TFs), microRNAs (miRNAs) and long noncoding RNAs (lncRNAs). However, the genetic networks underlying the lignin biosynthesis pathway for tree growth and wood properties remain unknown. Here, we used association genetics (additive, dominant and epistasis) and expression quantitative trait nucleotide (eQTN) mapping to decipher the genetic networks for tree growth and wood properties in 435 unrelated individuals of Populus tomentosa. We detected 124 significant associations (P ≤ 6.89E‐05) for 10 growth and wood property traits using 30 265 single nucleotide polymorphisms from 203 lignin biosynthetic genes, 81 TF genes, 36 miRNA genes and 71 lncRNA loci, implying their common roles in wood formation. Epistasis analysis uncovered 745 significant pairwise interactions, which helped to construct proposed genetic networks of lignin biosynthesis pathway and found that these regulators might affect phenotypes by linking two lignin biosynthetic genes. eQTNs were used to interpret how causal genes contributed to phenotypes. Lastly, we investigated the possible functions of the genes encoding 4‐coumarate: CoA ligase and cinnamate‐4‐hydroxylase in wood traits using epistasis, eQTN mapping and enzymatic activity assays. Our study provides new insights into the lignin biosynthesis pathway in poplar and enables the novel genetic factors as biomarkers for facilitating genetic improvement of trees.

Using immobilized enzymatic membrane reactor to treat synthetic phenol polluted drinking water

The catalyzed polymerization of phenol from the synthetic polluted drinking water using immobilized enzymatic membrane reactor (MER) was investigated. Horseradish peroxidase (HRP) immobilized microporous filter was prepared by porous calcium alginate method. The immobilized HRP demonstrates better performance for degradation of phenol. In addition, the experimental parameters including reaction time, pH, HRP dosage, and H2O2 concentration were optimized. In the condition of 0.1 mmol/L initial concentration of phenol,4.78u/ml HRP, nH2O2: nphenol=2:1 and reaction time 10 min at 20 °C and pH 7, the degradation of phenol reached 73.57%. Therefore, the immobilized enzymatic membrane reactor is feasible to treat synthetic phenol polluted drinking water.

Study on rheology and microstructure of phenolic resin cross-linked nonionic polyacrylamide (NPAM) gel for profile control and water shutoff treatments

Phenolic resin cross-linked polymer gel as a plugging agent for profile control and water shutoff has wide industrial applications. There have been many studies on the gel, but research on the rheology and microstructure has not been systematic. In this study, the rheological properties and microstructure of phenolic resin gel were measured by using a Haake Mars 60 rheometer and a Carl Zeiss Jena cryo-etching electron microscope. Viscosity and viscoelastic moduli of the gel rose constantly and the structure became denser during the gelation process. An increasing polymer or cross-linker concentration increased the viscosity and viscoelastic moduli of the gel. This increase is attributed to a higher polymer concentration contributing to form a stronger membrane structure and a higher cross-linker concentration making the density of the spherical particles higher. The addition of salt and acid affected the stability of the gel. As salinity increased or pH decreased, both the viscosity and viscoelastic moduli of the gel decreased. Combined with the microstructures of the gel systems, this outcome confirmed that salt and acid made the structure of the gel fragile and easily dehydrated. The results showed that phenolic resin gel (gelation temperature: 95 °C; aging time: 8 h) can maintain good stability under a salinity of less than 30,000 mg/L or alkaline conditions with pH > 7. This study can help to understand the gelation mechanism of phenolic resin gel and the impact mechanism of various factors.

Two-step enzymatic strategy for the synthesis of a smart phenolic polymer and further immobilization of a β-galactosidase able to catalyze transglycosydation reaction

A rapid and efficient enzymatic procedure for the preparation of an immobilized β-galactosidase has been described. In a first step, soybean peroxidase was used to catalyze the polymerization of a strategically activated phenol (N–Succinimidyl 3–(4–hydroxyphenyl)propionate, known as Bolton-Hunter reagent). The phenolic support was directly employed for immobilizing β–galactosidase from Bacillus circulans (ATCC 31382, β–Gal–3), giving rise to a new biocatalyst subsequently applied in the synthesis of a β–galatodisaccharide (Gal–β(1–3)–GlcNAc and Gal–β(1–3)–GalNAc). The reaction proceeded with high conversion rates and total regioselectivity. Reusability assays were performed with the same reaction conditions finding that the immobilized enzyme retains about 55% of its activity after eight batches. Finally and based on our results, the two-step enzymatic procedure presented here is a good and green alternative to the preparation of carbohydrates with biological activities.

Valorization of Kraft Lignin of Different Molecular Weights as Surfactant Agent for the Oil Industry

After cellulose, lignin is the second most abundant biopolymer in the vegetable world. Since lignin is a natural phenolic polymer, there are a variety of potential products obtainable by its chemical modification, including surfactants. In this regard, lignin is of great interest because represent a byproduct of pulp industries for papermaking; however, this byproduct can be harnessed for obtaining aromatic derivatives of industrial interest. In this work, alkali lignin derivatives of different molecular weights were synthesized from lignin fractions from Pinus caribaea obtained by ultrafiltration. Lignin and lignin-fractions were modified with succinic anhydride (SA), and dodecyl-succinic anhydride (DSA) under microwave heating. The reaction was monitored by Fourier Transform Infrared Spectroscopy. The surface activity of lignin, and lignin-derivatives was evaluated through surface tension measurements, while the stability of suspensions and emulsions was evaluated by the volumetric separation method. The lignin fractions, and the esterified derivatives were obtained in very short reaction times (90–110 s) using a mixture of acetonitrile/ethanol. The lignin-derivatives showed higher surface activity in comparison to the neat lignin. Derivatives prepared from the lower molecular weight fraction by using DSA showed the best emulsifying properties. Lignin-derivatives also showed significant dispersing properties in comparison to a commercial dispersant (lignosulfonate). The best dispersant properties were obtained from the higher molecular weight ultrafiltered lignin fraction esterified with SA.

Rationalizing the regioselectivity of cationic ring-opening polymerization of benzoxazines

Polybenzoxazines have gained increasing interest both in industry and academia for the last few decades due to their unique structural features. The ring-opening polymerization mechanism of 1,3-benzoxazine monomers and the regioselectivity during polymerization, still need further clarification. In this study, ring-opening polymerization mechanisms of two methyl substituted benzoxazine derivatives 3,6-dimethyl-3,4-dihydro-2H-benzo[e][1,3] oxazine (pC-m) and 3,5,6,7-tetramethyl-3,4-dihydro-2Hbenzo[e][1,3] oxazine (345TMP-m) are investigated by quantum mechanical tools using density functional theory (DFT). Calculations have shown that in the presence of a nucleophile, pC-m can yield the phenolic polymer upon rearrangement of its intermediate phenoxy product. However, the polymerization of 345TMP-m results in a mixture of phenoxy and phenolic type polymers. The extra methyl groups on 345TMP-m have a dual role in preventing the π stacking interactions observed in pC-m, and in decreasing the barrier yielding phenolic polymers by electron donation.

Polymer Technology of Porous SiC Ceramics Using Milled SiO2 Fibers

The paper describes a developed polymer composition and a process for manufacturing highporous chemically pure silicon carbide ceramics from this composition, using milled industrial wastes of quartz fiber non-woven fabrics as the source of silicon dioxide, which is important as a rational utilization of these wastes. The necessity of pre-milling of the SiO2 fibers was experimentally substantiated. Without this stage, the duration of treatment at 1400°C under dynamic vacuum considerably (≥12 h) increased, because of the non-uniform distribution of the components in the polymer composite. In the case of stoichiometric ratio of SiO2 and carbon formed upon pyrolysis of the polymeric phenol binder, the obtained SiC ceramic contained a large amount of unreacted carbon. This indicaties that side reactions take place to give volatile silicon monoxide, which is distilled off from the reactor. The effects of the milling time of SiO2 fibers and the carbothermal reduction temperature on the elemental and phase composition, density, and porosity of the obtained samples and the ultimate compressive strength were studied. Analysis of the experimental results served for optimization of the composition of the initial polymer composites. As a result, highly porous (83%) and relatively strong (ultimate compressive strength of 8.2MPa) SiC-ceramic samples free from unreacted carbon and silicon dioxide and other stubborn impurities were fabricated at 1400°C (dynamic vacuum, heat treatment for 4 h).

Simple and sensitive detection of 4-nitrophenol in real water samples using gold nanoparticles modified pretreated graphite pencil electrode

A novel, simple, sensitive and disposable gold nanoparticles modified pretreated graphite pencil electrode (AuNPs-PGPE) has been developed to overcome the surface fouling of carbon electrodes due to polymerization of phenols. The unmodified PGPE electrode displayed distinct electrocatalytic properties while reducing 4-nitrophenol (4-NP). The PGPE was prepared using a simple electrochemical treatment step of the bare GPE in NaOH solution, and the resulting electrode exhibited highly sensitive, selective and fast performance towards the determination of 4-NP. The influence of various voltammetric techniques as well as other related factors affecting the reduction peak current of 4-NP was investigated. The reduction current against 4-NP concentration at PGPE displayed a good linearity between 0.01 μM to 0.8 μM with R2 = 0.9994. The PGPE was further modified by AuNPs to increase the working range of PGPE for sensing 4-NP. Both of the developed PGPE and AuNPs-PGPE could be employed to a vast concentration range of 4-NP varying between 0.01 and 100 μM. The modified electrodes were successfully tested at different amounts of 4-NP varying form low concentration 0.2 μM to high concentration i.e. 25 μM in water models.

Mesoporous phenolics filled in macroporous membranes for tunable tight-ultrafiltration

Separation of colloidal nanoparticulates requires tight ultrafiltration (TUF) membranes. Phenolic polymers with well-defined sub-10 nm mesopores are promising candidates for such membranes, but suffer from intrinsic fragility. Herein, robust mesoporous phenolic membranes with flexibly adjustable TUF functions are realized through a new pore-filling strategy. Phenolic prepolymers with tunable fluidity are spontaneously filled into macroporous substrates with precisely controllable filling depths. Subsequent thermopolymerization fully cures the prepolymer and acid soaking removes the templating pluronic copolymers, producing composite TUF membranes with mesoporous phenolics embedded in flexible substrates. The membranes exhibit widely adjustable molecular-weight-cut-offs (MWCOs) (2.6–41 kg/mol) depending on the filling depth of phenolics while maintain otherwise unattainable high permeabilities. We further investigate the separation of CdTe and carbon quantum dots dispersed in water and toluene by these membranes, and they show excellent concentration and fractionation effect. This work enables efficient separation of ultra-small colloids by robust TUF membranes.

Facile enzymatic preparation of fluorescent conjugated polymers of phenols and their application in sensing

ABSTRACTThe recognized drawback of utilizing metal catalysts for the synthesis of fluorescent conjugated polymers (CP) is the requirement for extensive purification to ensure complete removal of residual catalyst that would otherwise quench the fluorescence. In addition, typical synthesis of fluorescent CP involves multiple steps, monomers and solvents with varying levels of toxicity. This work demonstrates the possibility of utilizing oxidoreductase enzymes as the catalyst, for the one step polymerization of naturally occurring phenols to yield fluorescent conjugated polyphenols. The metal in the active site of the enzyme remains chelated during the synthesis allowing the polymers to be fluorescent as synthesized without the need for extensive purification. Three natural phenols, 4‐hydroxyphenylacetic acid, hydroxytyrosol, and chlorogenic acid were polymerized using Horseradish peroxidase as the biocatalyst. Spectroscopic techniques, UV–vis, Fourier transform infrared Spectroscopy–Attenuated Total Reflectance, and fluorescence, are used to characterize chemical structure and photoluminescence of these polymers. The polyphenols exhibit fluorescence with significant stokes shift in the range 30–100 nm rendering them useful in fluorescence quenching‐based sensors. Preliminary studies on use of these polymers, in the detection of nitro‐aromatic compounds in solution through using fluorescence‐quenching are also presented. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46496.