Search

Instead of using finite petroleum-based resources and harmful additives, starch can be used as a biodegradable, low-cost, and non-toxic ingredient for green adhesives. This work employs K3PO4 catalyzed transesterifications of cassava starch and methyl laurate at varying reaction times (1–10 h), resulting in the enhanced hydrophobicity of starch laurates. At longer reaction times, starch laurates having higher degrees of substitution (DS) were obtained. While starch laurates are the major products of transesterification, relatively low-molecular-weight byproducts (1%) were detected and could be hydrolyzed starches based on gel permeation chromatography results. Contact angle measurements confirmed the relatively high hydrophobicity of the modified starches compared with that of native starch. The modified starches were then employed to prepare water-based adhesives on paper (without any additional additives). Notably, the shear strength of the esterified starch adhesives appears to be independent of the DS of esterified samples, hence the transesterification reaction times. Additionally, the shear strength of water-based adhesives (0.67–0.73 MPa) for bonding to paper substrates is superior to that of two other commercially available glues by a factor of 10 to 80 percent. [ABSTRACT FROM AUTHOR]

Paper-based packaging is experiencing a resurgence due to its inherent biodegradability and recyclability. To meet the barrier properties required for certain applications, a coating is necessary. This coating must enhance functionality without compromising the environmental sustainability of the substrate. With this goal in mind, we prepared waterborne dispersions of biodegradable poly(lactic acid) (PLA) using a PEG-PLA-PEG triblock copolymer as the main surfactant. We achieved formulations with good stability over a 6-month period and high solids content (∼40 wt%). The waterborne dispersions underwent analysis by dynamic light scattering (DLS), size exclusion chromatography (SEC), gravimetric tests, and rotational rheology with and without xanthan gum (0.2–0.8 wt%) as a thickener. Subsequently, the thickened dispersions were coated at 60 °C onto a paper substrate. SEM analyses revealed the formation of a polymer layer on the paper surface with thickness and morphology dependent on the processing conditions. Partial interpenetration between the coating and the paper fibers was observed, resulting in excellent adhesion between the layers. The coated paper exhibited good barriers to liquid and water vapor, with Cobb60 < 5 g/m2 and water vapor transmission rate (WVTR) < 100 g/(m2∙day) for coating weights ≤15 g/m2, comparable to the performance of solvent-based PLA paper coatings. The surface energy of the coating was approximately 50 dyne/cm, higher than that of neat PLA, making it suitable for printing with common inks. Furthermore, the coated paper can be fully pulped in water, indicating that it can still be recycled in the paper stream, albeit with potentially increased processing time due to the coating weight. [Display omitted] • A PEG-PLA-PEG block copolymer was proven to stabilize waterborne PLA dispersions. • Dispersions with 40 % solid content were obtained. • The dispersions thickened with xanthan gum were successfully coated on paper at 60 °C. • PLA-coated paper had similar water barrier properties to its oil-based counterpart. • Repulping of PLA-coated paper is possible but slower than for uncoated paper. [ABSTRACT FROM AUTHOR]

• Lignin additive extracted using H 2 SO 4 (L-S) had high phenolic content and pH value. • Asphalt with L-S additive had the lowest reduction of crossover modulus due to aging. • Incorporating L-S into asphalt reduces the increase of asphaltene fraction due to aging. • FTIR test is more sensitive in measuring the lignin antioxidant performance than DSR and GPC. The main objective of this research is to investigate the effectiveness of lignin bio-additives derived from black liquor paper pulp as asphalt antioxidants. Two lignin bio-additives, H-L and S-L, were developed by acidifying black liquor with hydrochloric and sulfuric acid. The laboratory aging procedures used in this study included the Rolling Thin Film Oven and the Ultraviolet Chamber methods. The crossover modulus (|G* c |) and linear amplitude sweep (LAS) were measured using a Dynamic Shear Rheometer (DSR). Gel Permeation Chromatography (GPC) was also used to characterize the molecular size distribution of the asphalt binder. The combination of carbonyl and sulfoxide aging indices was measured using Fourier Transform Infrared (FTIR) spectroscopy. The S-L modified binder (S-LMB) demonstrated superior aging resistance compared to both the control binder (CB) and the H-L modified binder (H-LMB) by exhibiting the lowest reduction in |G* c |. Furthermore, the LAS test results showed that S-LMB provided the best resistance to aging due to the lowest decrease in fatigue life with age conditioning, followed by CB and H-LMB, with rates of 11%, 13%, and 16%, respectively. The GPC results also confirmed the efficacy of the S-L bio-additive as an antioxidant, exhibiting the lowest increment in asphaltene proportion attributed to age conditioning. The FTIR measurements successfully captured the antioxidant capability of both H-L and S-L bio-additives, with S-L performing better than H-L. Overall, the results suggest that S-L demonstrates superior antioxidant performance compared to H-L. [ABSTRACT FROM AUTHOR]

The core of decorative laminates is generally made of stacked Kraft paper sheets impregnated with a phenolic resin. As the impregnation process in industry is relatively fast, new methods need to be developed to characterize it for different paper-resin systems. Several phenolic resins were synthesized with the same Phenol:Formaldehyde ratio of 1:1.8 and characterized by Fourier Transform Infrared Spectrometry (FTIR) as well as Size-Exclusion Chromatography (SEC). In addition, their viscosities and surface tensions when diluted in methanol to 45% of solid content were measured. The capacity of each resin to penetrate a Kraft paper sheet was characterized using a new method, which measures the conductivities induced by the liquid resin crossing the paper substrate. With this method, crossing times could be measured with a good accuracy. Surprisingly, the results showed that the penetration time of the resin samples is not correlated to the viscosity values, but rather to the surface tension characteristics and the chemical characteristics of paper. Furthermore, some resins had a higher swelling effect on the fibers that delayed the crossing of the liquid through the paper. [ABSTRACT FROM AUTHOR]

Highlights: [•] Oxidative group profiling of small ancient cellulose fragments coated with beeswax. [•] The main mechanism of deterioration was identified for the first time. [•] Beeswax coated cellulose was purely hydrolytically damage, no oxidation. [•] Hydrolysis caused by microorganisms secreting cellulolytic enzymes. [ABSTRACT FROM AUTHOR]

Abstract: Resin fractionation (XAD-8), high performance size exclusion chromatography (HPSEC) UV260 and 280 nm and HPSEC-fluorescence techniques were used to characterise very hydrophobic acid (VHA) and slightly hydrophobic to hydrophilic (Non-VHA) compounds in treated wastewater from a Pinus radiata (Sulfite) pulp and paper mill that incorporates aerated stabilisation basins (ASBs). The use of these techniques enabled a rigorous evaluation of ASB performance with coagulation pre-treatment, using laboratory-based simulation studies and a full-scale ASB. The laboratory scale ASB treatment comprised two parallel sets of three tanks (A and B) that were operated over three hydraulic retention times (HRTs) of 84days. Simulations were based on the full-scale HRT. The influent used for both simulations was post-coagulated pulp mill mixed with paper mill wastewater (1:2). Sludge collected from the full scale ASB pond system was added to the tanks of both simulations for inoculation with indigenous microorganisms. In addition, settled sludge collected after coagulation of pulp mill wastewaters was added to simulation B to investigate the effects of alum flocculated material. Coagulation pre-treatment with alum removed HMW compounds (∼3–8kDa), and alum sludge addition to further simulate potential long-term application of coagulation as a pre-treatment step prior to ASB resulted in further removal of HMW components. SUVA and specific colour of wastewaters increased during ASB treatment with the least colour formation occurring in Simulation B. There were no significant differences in DOC, UV–visible absorbance and total relative abundance of VHA and Non-VHA compounds between pre-coagulated (A and B) and untreated waters following ASB, except for a HMW of VHA component of ∼1700Da, which was attributed to the significant colour development in the treated wastewater. The use of these analytical tools provided insight on the fate and transformation of recalcitrant organic compounds typically present in pulp and paper mill effluents. [Copyright &y& Elsevier]

In order to investigate a synergetic role of water and oxygen in the degradation of permanent paper in archiving climate, accelerated ageing in three different conditions was conducted: humid air, humid nitrogen and dry air. This allowed to decouple acid-catalysed hydrolysis versus oxidation of cellulose. After ensuring the reliability of the ageing experiment, the degradation state of the paper was assessed. Various techniques (size exclusion chromatography, pH extraction, alkaline reserve, paper colour and water content) were used. It appeared that the cellulose scission rate of the Canson® permanent paper was reduced compared to the Whatman No. 40 acidic cotton paper used as reference, but not in the same proportion for all the ageing conditions. This was attributed to a lower acidification, inhibiting acid-catalysed hydrolysis, due to the presence of the alkaline reserve. The degradation mechanisms are the same for both papers, which exhibited a similar chemical and physical degradation. [Display omitted] [ABSTRACT FROM AUTHOR]

Investigates the degradation of paper and pulp samples which had undergone various artificial aging treatments, using size-exclusion chromatography. Details of the accelerated aging treatments; Influence of the treatment on the relationship between zero-span tensile strength; Characterization of an 18th-century document.

Two key challenges in the multidisciplinary field of sequence‐controlled polymers are their efficient synthesis and the establishment of correlation with polymer properties. In this context, in this paper, gradient architecture in the hydrophobic tail of an amphiphile is implemented and synthesized for a fixed hydrophilic unit (polyethylene glycol, PEG), by means of two monomers (2‐hydroxypropyl methacrylate, HPMA, and diacetone acrylamide, DAAM) of contrasting reactivities. The resulting non‐biochemical gradient sequence‐controlled polymers are generated from a one‐pot, homogeneous mixture through a PET‐RAFT‐PISA (photoinduced electron/energy transfer‐reversible addition‐fragmentation chain transfer‐polymerization‐induced self‐assembly) method. In addition, the initial concentration ratio of the monomers in the gradient is varied as an input for a set of fixed experimental parameters and conditions, and its correlation with kinetics, gradient and self‐assembled morphologies is established, as the output of the process. These results are extensively corroborated via nuclear magnetic resonance (NMR) spectroscopy analysis, together with transmission electron microscopy (TEM) images, dynamic light scattering (DLS), and gel permeation chromatography (GPC) experiments. These results have implications for chemical computation carried out by PISA, programmable self‐assembly, information storage, biomimetics, origins of life and synthetic protocell studies. [ABSTRACT FROM AUTHOR]

In present paper, structures and properties of degradation products of polystyrene (PS) waste were characterized by gel permeation chromatography (GPC), thermogravimetric (TG) analysis, Fourier transform infrared (FT-IR) spectroscopy, gas chromatography-mass spectrometry (GC-MS), and thus the degradation conditions including temperature, time, and assistant type and dosage were investigated and optimized. It is suitable to use 1.0 wt% K2S2O8 as an assistant to degrade PS waste at 300°C for 24 h. Subsequently by sulfonation and neutralization reactions, the degraded PS was prepared into sodium polystyrene sulfonate (PSS), a common dispersant for coal‒water slurry (CWS). The performance of PSS with different molecular weights and sulfonation degrees was studied. Experimental results showed that the PSS with the sulfonation degree of more than 75%, prepared from the degraded PS having number average molecular weight (Mn) of about 9000, was appropriate for dispersion and stabilization of CWS suspensions. Additionally, compared with commercial dispersant NSF, the obtained PSS had a better performance for CWS. CWSs prepared with dispersant PSS exhibited pseudo-plastic or shear-thinning rheological behaviors. Combined with coal‒water slurry technology, a new approach is provided for resource utilization of PS waste. [ABSTRACT FROM AUTHOR]

The elution by imidazole is used in the purification process of non-alpha IL-2 mutein, specifically in the immobilized metal chelates affinity chromatography step (IMAC). In order to demonstrate that a new elution process is possible using cheaper solutions, changes were made in the former capture step. These changes consist on separate the size exclusion chromatography and the controlled oxidation stage which are currently performed together, as well as changing the elution solution. To achieve this, a 22 factorial design of experiments was performed to evaluate the effect of pH and molar concentration on recovery, purity, and particle diameter. The best results were obtained with the solution of sodium acetate 20 mmol L-1 pH 4 being similar to those obtained in the industry nowadays: 29 % recovery, 90 % of purity, and particle diameter 18,40 nm. The first contribution of this paper is to demonstrate the feasibility of using the new elution methodology. Moreover, by using the academic software SuperPro Designer, the actual capture step of the purification process (elution by Imidazole) was simulated, validated, and verified. To demonstrate the relationship between costs and benefits, the CH SFF matrix gel volume was incremented. This change increased costs at this stage. However, the productivity obtained grew to 109 mg h-1, 2.78 times greater than the current productivity. Therefore, the gross net increased by 879 325, 00 $. This result constitutes the second contribution of this paper. [ABSTRACT FROM AUTHOR]

Abstract: The degradation of cellulose is an important factor influencing its physical, mechanical, optical and chemical properties and the longevity of paper in the electrical industry and in stored paper and books. A study of the accelerated ageing of newsprint paper has been performed at 98 °C during 0, 1, 2, 3, 5, 7, 10, 15, 20, 30 and 60 days. Degradation has been studied by viscometry, gel permeation chromatography (GPC) and saccharides determination. In the first stages of the accelerated ageing the cellulose depolymerisation takes place homogeneously (mainly due to the hydrolysis), later other reactions (oxidation, crosslinking) take place. The saccharides content in the paper decreases and the hemicelluloses are degraded faster. [Copyright &y& Elsevier]

Abstract: Background: Filter paper bloodspot samples exhibit increased red cell concentration near the bloodspot perimeter compared to the interior. We examined whether simulation of size exclusion chromatography separating cell and liquid components during bloodspot formation was consistent with the observed red cell distribution. Methods: Whole blood was defined as a mixture of 60% liquid and 40% solids (hematocrit). Bloodspot formation was simulated by step-wise center additions of 1 μl blood up to a total volume of 50 μl. Partitioning of the liquid component of the liquid volume into space not available to the solid component was calculated using a partitioning coefficient K =Vi /Vm, where Vi is the immobile (stationary) liquid volume and Vm is the mobile liquid volume. After each volume addition step, relative red cell concentration was calculated as the solids volume fraction of total volume as a function of radial distance from the center. Results: Simulation for K =0.3 resulted in final red cell distribution that was quantitatively consistent with bloodspot data. Conclusions: Increased perimeter red cell concentration in bloodspots is consistent with partitioning of the liquid fraction into mobile and immobile components during bloodspot formation according to the principles of constant-load size exclusion chromatography. [Copyright &y& Elsevier]

In order to identify potential genotoxicant(s) in recycled paperboard, samples were fractionated using multiple liquid/liquid extraction, and gel permeation chromatography, and analysed by gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry. The rec -assay was used as an indicator of genotoxicity. Genotoxicants in the recycled paperboard were identified as dehydroabietic acid (DHA) and abietic acid (AA). DHA and AA were detected in two out of five virgin products, and in all seven recycled products for food-contact use. Total amounts of DHA and AA were 240 and 990&ThickSpace;µg/g in the virgin products and 200-990&ThickSpace;µg/g in the recycled products. A good correlation was observed in the total amount of DHA and AA content determined in paper products and DNA-damaging activity. Moreover, genotoxic effects in paper products showed a good match with standard compounds, indicating that the genotoxic effects of these paper products was mostly attributable to DHA and AA. [ABSTRACT FROM AUTHOR]

A strain designated GUMF5 was isolated in Goa-India from sediments of Dead Sea-Israel and identified as haloarchaeon Halomicroarcula pellucida based on 16S rRNA gene analysis similarity value of 99.84%. Strain GUMF5 grew on mineral salts medium with 20% NaCl and 0.5% carboxymethyl cellulose-sodium (CMC-Na) as a sole source of carbon and produced haloextremozyme cellulase. The enzyme was concentrated using Sephadex G20, precipitated with ethanol, dialyzed and retentate purified using Sephadex G200, the size exclusion chromatography. A yield of 78.53% cellulase with an activity of 131.13 U/mg and 1.24-fold purity was obtained. The purified cellulase had optimum activity at 20% NaCl, at 40 ºC, 0.5% CMC-Na, pH 7 and 150 rpm. SDS-PAGE combined with zymographic analysis revealed the molecular weight of cellulase as 240 kDa, 40 kDa and 17.4 kDa. The activity of the enzyme was stimulated by metallic cations in the order of Ca+2 > Mn+2 > Mg+2 > SO42− > NH4+ and was inhibited by Ag+ > Fe+2 > Cu+2. Methanol and ethanol enhanced the cellulase activity by 6% and 26%, respectively. The haloextremozyme cellulase degraded Whatman No. 1 filter paper indicated in scanning electron micrographs, exposure of open pores and fibers without any intra connectivity corresponding to paperase activity and implicating the possible use of enzyme to bio-convert cellulosic waste. Conclusively, Halomicroarcula pellucida GUMF5 (Accession number: MH244431), globally, is the only Halomicroarcula pellucida isolated from the sediments of Dead Sea producing haloextremozyme cellulase, and hence is an important biotechnological resource. [ABSTRACT FROM AUTHOR]

Abstract: A sequence of treatments consisting of an initial xylanase treatment followed by cold alkaline extraction and a final endoglucanase treatment was investigated as a process for upgrading non-wood paper-grade pulps to dissolving-grade pulps for viscose production. Five commercial dried bleached non-wood soda/AQ paper pulps, from flax, hemp, sisal, abaca, and jute, were studied for this purpose. Commercial dried bleached eucalyptus dissolving pulp was used as reference sample. Sisal pulp showed the highest improvement in Fock’s reactivity, reaching levels nearly as high or even higher than that of eucalyptus dissolving pulp (65%), and a low hemicellulose content (3–4%) when was subjected to this sequence of treatments. The viscosity, however, decreased considerably. A uniform and narrow molecular weight distribution was observed by size exclusion chromatography. 13C nuclear magnetic resonance spectroscopy and Raman microspectroscopy revealed that the cellulose structure consisted of cellulose I. [Copyright &y& Elsevier]

UV debonding acrylate pressure-sensitive adhesives (UPSAs) are necessarily applied in the semiconductor industry. To establish a comprehensively understood method is important to detect their bonding and debonding behaviors. In this paper, rheological methods, including Three Interval Thixotropy tests (3ITT) and Tack test modes were used for characterizing series of UPSAs. Vinyl groups were successfully grafted onto the acrylate copolymer chains through isocyanate condensation reactions, which were characterized by nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy and gel permeation chromatography. From the maximum normal force in the Tack test modes, UPSAs after UV irradiation showed obvious debonding behaviors in short-time stress analysis. The recovery percentage of the storage modulus in 3ITT tests indicated that 0.6 wt% isocyanate curing agent made the UPSAs good resistance to deformation. Under the limit of 30 wt% pentaerythritol diacrylate (PETA), the rheological adhesion performance of UPSAs increases accordingly with the PETA content, which was also confirmed by 180° peel strength tests. From the microscope images of the wafer surfaces after peeling off the UPSA tapes, rheological characterization methods can help designing UPSAs with clean debonding properties. [ABSTRACT FROM AUTHOR]

The properties of nanomedicines will influence how they can deliver drugs to patients reproducibly and effectively. For conventional pharmaceutical products, Chemistry, Manufacturing and Control (CMC) documents require monitoring stability and storage conditions. For nanomedicines, studying these important considerations is hindered by a lack of appropriate methods. In this paper, we show how combining radiolabelling with size exclusion chromatography, using a method called SERP (for Size Exclusion of Radioactive Polymers), can inform on the in vitro degradation of polymer nanoparticles. Using nanoparticles composed of biodegradable poly(lactic acid) (PLA) and poly(lactic- co -glycolic acid) (PLGA), we show that SERP is more sensitive than dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA) to detect degradation. We also demonstrate that the properties of the polymer composition and the nature of the aqueous buffer affect nanoparticle degradation. Importantly, we show that minute changes in stability that cannot be detected by DLS and NTA impact the pharmacokinetic of nanoparticles injected in vivo. We believe that SERP might prove a valuable method to document and understand the pharmaceutical quality of polymer nanoparticles. [Display omitted] [ABSTRACT FROM AUTHOR]

Polymers with cyclic topology have no terminal structure and, therefore, exhibit various unique physical and functional properties compared to those of linear analogs. In this paper, we report an innovative methodology for the synthesis of cyclic polymers via ring-expansion RAFT (RE-RAFT) polymerization of vinyl monomers using a cyclic trithiocarbonate derivative (CTTC) as a RAFT agent. RE-RAFT of tert-butyl acrylate (TBA) was performed to yield a mixture of polymers exhibiting a bimodal size exclusion chromatography (SEC) trace. Both the peak top molecular weights shifted to higher-molecular-weight regions as the monomer conversion increased. The structure of the resulting polymer mixture was examined by 1H NMR and MALDI-TOF-MS. Detailed studies indicated that the obtained polymer of higher molecular weight was one of the large-sized cyclic polymers generated by the fusion of smaller-sized cyclic polymers during the RE-RAFT polymerization process. This approach opens the door to the simple synthesis of well-controlled cyclic polymers with complex structures, such as alternating and multi-block repeat unit sequences. [ABSTRACT FROM AUTHOR]

Glycidyl-based chain extenders are broadly used as processing aids to enhance the physical properties of polyesters, but glycidyl-containing compounds have severe toxicity concerns. Reported herein are glycidyl-free chain extenders produced via the grafting of 9-(oxiran-2-yl)nonyl methacrylate (EAT) and 8-(3-octyloxiran-2-yl)octyl methacrylate (EAI) on biodegradable poly(e-caprolactone) (PCL). EAI and EAT were grafted onto PCL via free radical grafting using melt extrusion to produce PCL-epoxy-grafted PCL-g-EAI and PCL-g-EAT. The obtained PCL-g-EAI and PCL-g-EAT were characterized by 1H nuclear magnetic resonance (NMR) spectroscopy, intrinsic viscosity measurements, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and size exclusion chromatography (SEC). Using reactive melt extrusion, PCL-g-EAI and PCL-g-EAT were tested as potential chain extenders for poly(lactic acid) (PLA). PCL-g-EAI showed comparable or better mechanical properties than those of the commercial chain extender Joncryl ADR. A cytotoxicity assay has been conducted on PLA samples with the new chain extender and showed the absence of cytotoxicity in all samples. The outcomes reported in this paper offer new opportunities for the development of safer chain extenders. [ABSTRACT FROM AUTHOR]

This paper presents studies on the influence of the chemical structure of (meth)acrylic monomers on the properties of powder coatings based on polyacrylate resins. For this purpose, a wide range of monomers were selected—2-hydroxyethyl methacrylate (HEMA), methyl methacrylate (MMA), n-butyl acrylate (nBA), tert-butyl acrylate (tBA), dodecyl acrylate (DA), ethyl acrylate (EA) and benzyl acrylate (BAZ)—for the synthesis of the polyacrylate resin. The average molecular mass and molecular mass distribution of the synthesized resins were measured by gel permeation chromatography (GPC). The glass transition temperature (Tg) and viscosity of polyacrylate resins were determined by using differential scanning calorimetry (DSC) and a Brookfield viscometer. These parameters were necessary to obtain information about storage stability and behavior during the application of powder clear coatings. Additionally, DSC was also used to checked the course of the low-temperature curing reaction between the hydroxyl group contained in the polyacrylate resin and the blocked polyisocyanate group derived from a commercial agent such as Vestanat B 1358/100. The properties of the cured powder clear coatings were tested, such as: roughness, gloss, adhesion to the steel surface, hardness, cupping, scratch resistance, impact resistance and water contact angle. The best powder clear coating based on the polyacrylate resin L_HEMA/6MMA/0.5nBA/0.5DA was characterized as having good scratch resistance (550 g) and adhesion to the steel surface, a high water contact angle (93.53 deg.) and excellent cupping (13.38 mm). Moreover, its crosslinking density (CD) and its thermal stability was checked by using dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). [ABSTRACT FROM AUTHOR]

Improving the aging resistance of waterproof membranes is very important to extend their service life. In this paper, organic montmorillonite (OMMT) was used to enhance the aging resistance of styrene-butadiene-styrene (SBS) modified bitumen (SMB) for waterproofing. The effect of OMMT on the physical properties, chemical structure, and micromorphology of SMB membranes before and after heat aging were investigated, and the service life of the SMB membranes was predicted based on the Arrhenius model. The results indicated that the high- and low-temperature performance of SMB was improved due to the addition of OMMT, and the optimal dosage of OMMT was 3%. After 20 days of heat aging at 80°C, the alterations of softening point increment, low-temperature flexibility decrement, and viscosity aging index of OMMT/SMB decreased by 1.5°C, 3°C, and 14.7%, respectively, compared with that of SMB, which indicated that OMMT can enhance the aging resistance of SMB waterproof membranes. Fourier-transform infrared spectroscopy indicated that the change of IC═O , IS═O , and IC═C of 3% OMMT/SMB was 53.5%, 45.6%, and 53.2% less, respectively, than SMB after 20 days of heat aging at 80°C, which shows that OMMT can inhibit the change of carbonyl, sulfoxide, and butadiene double bonds of SMB. The gel permeation chromatography showed that OMMT can hinder the degradation of SBS and polycondensation of bitumen during heat aging. The fluorescence microscope showed that OMMT/SMB maintained a more complete network structure than SMB after heat aging. According to the Arrhenius model, based on the 0°C flexibility as the damage point and the temperature of waterproof materials under sunlight being 60°C for an annual sunshine time of 1,200 h, the service life of SMB and OMMT/SMB were predicted to be 16.90 and 21.32 years, respectively. [ABSTRACT FROM AUTHOR]

Tissue paper is of high importance worldwide and, continuously, research is focused on improvements of the softening and durability properties of the paper which depend specifically on the production process. Polyamide-amine-epichlorohydrin (PAE) resins along with release agents are widely used to adhere the paper to the yankee dryer (creping cylinder) in paper manufacture. Nevertheless, these resins are highly cationic and they normally adhere in excess to the paper which negatively affects the creping process and the quality of the paper. For this reason, a low cationic polyamine-epichlorohydrin coating (Polycoat 38®) was synthesized from a diamine supplied by Disproquin S.A.S. and epichlorohydrin. The analysis of the synthesized polymer was carried out by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H-NMR). The molecular weight of the polymer was obtained by gel permeation chromatography (GPC), physical-chemical properties such as kinematic viscosity, percentage of solids, density, charge density were measured and compared with a commercial PAE resin (Dispro620®) Thermal stability of the Polycoat 38® and glass transition temperature in presence of a release agent (Disprosol 17®) were also evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. Finally, a peel adhesion test and an absorption durability assessment were carried out together with the evaluation of the creeping efficiency of the paper by caliber and tensile measurements in a tissue (towel paper) production plant, demonstrating a superior performance in the paper creping process as compared to some commercially available products. [ABSTRACT FROM AUTHOR]

In this paper, the bio-based raw material erythritol was used to introduce an acetal structure into the benzoxazine resins. The benzoxazine-based resins containing an erythritol acetal structure could be degraded in an acidic solution and were environmentally friendly thermosetting resins. Compounds and resins were characterized by 1H nuclear magnetic resonance (1H NMR) and Fourier-transform infrared (FT-IR) analyses, and melting points were studied by a differential scanning calorimeter (DSC); the molecular weight was analyzed by gel permeation chromatography (GPC). The dynamic mechanical properties and thermal stability of polybenzoxazine resins were studied by dynamic mechanical thermal analysis (DMTA) and a thermogravimetric analyzer (TGA), respectively. The thermal aging, wet-heat resistance, and degradation properties of polybenzoxazine resins were tested. The results showed that the polybenzoxazine resins synthesized in this paper had good thermal-oxidative aging, and wet-heat resistance and could be completely degraded in an acidic solution (55 °C DMF: water: 1 mol/L hydrochloric acid solution = 5:2:4 (v/v/v)). [ABSTRACT FROM AUTHOR]

The depletion of natural resources and increasing environmental apprehension regarding the reduction of harmful isocyanates employed in manufacturing polyurethanes (PUs) have generated significant attention from both industrial and academic sectors. This attention is focused on advancing bio-based non-isocyanate polyurethane (NIPU) resins as viable and sustainable substitutes, possessing satisfactory properties. This review presents a comprehensive analysis of the progress made in developing bio-based NIPU polymers for wood adhesive applications. The main aim of this paper is to conduct a comprehensive analysis of the latest advancements in the production of high-performance bio-based NIPU resins derived from lignin and tannin for wood composites. A comprehensive evaluation was conducted on scholarly publications retrieved from the Scopus database, encompassing the period from January 2010 to April 2023. In NIPU adhesive manufacturing, the exploration of substitute materials for isocyanates is imperative, due to their inherent toxicity, high cost, and limited availability. The process of demethylation and carbonation of lignin and tannin has the potential to produce polyphenolic compounds that possess hydroxyl and carbonyl functional groups. Bio-based NIPUs can be synthesized through the reaction involving diamine molecules. Previous studies have provided evidence indicating that NIPUs derived from lignin and tannin exhibit enhanced mechanical properties, decreased curing temperatures and shortened pressing durations, and are devoid of isocyanates. The characterization of NIPU adhesives based on lignin and tannin was conducted using various analytical techniques, including Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), matrix-assisted laser desorption/ionization with time-of-flight (MALDI-TOF) mass spectrometry, and gel permeation chromatography (GPC). The adhesive performance of tannin-based NIPU resins was shown to be superior to that of lignin-based NIPUs. This paper elucidates the potential of lignin and tannin as alternate sources for polyols in the manufacturing of NIPUs, specifically for their application as wood adhesives. [ABSTRACT FROM AUTHOR]

A strain designated GUMF5 was isolated in Goa-India from sediments of Dead Sea-Israel and identified as haloarchaeon Halomicroarcula pellucida based on 16S rRNA gene analysis similarity value of 99.84%. Strain GUMF5 grew on mineral salts medium with 20% NaCl and 0.5% carboxymethyl cellulose-sodium (CMC-Na) as a sole source of carbon and produced haloextremozyme cellulase. The enzyme was concentrated using Sephadex G20, precipitated with ethanol, dialyzed and retentate purified using Sephadex G200, the size exclusion chromatography. A yield of 78.53% cellulase with an activity of 131.13 U/mg and 1.24-fold purity was obtained. The purified cellulase had optimum activity at 20% NaCl, at 40 ºC, 0.5% CMC-Na, pH 7 and 150 rpm. SDS-PAGE combined with zymographic analysis revealed the molecular weight of cellulase as 240 kDa, 40 kDa and 17.4 kDa. The activity of the enzyme was stimulated by metallic cations in the order of Ca+2 > Mn+2 > Mg+2 > SO42− > NH4+ and was inhibited by Ag+ > Fe+2 > Cu+2. Methanol and ethanol enhanced the cellulase activity by 6% and 26%, respectively. The haloextremozyme cellulase degraded Whatman No. 1 filter paper indicated in scanning electron micrographs, exposure of open pores and fibers without any intra connectivity corresponding to paperase activity and implicating the possible use of enzyme to bio-convert cellulosic waste. Conclusively, Halomicroarcula pellucida GUMF5 (Accession number: MH244431), globally, is the only Halomicroarcula pellucida isolated from the sediments of Dead Sea producing haloextremozyme cellulase, and hence is an important biotechnological resource. [ABSTRACT FROM AUTHOR]

Abstract: The paper deals with the application of size exclusion chromatography (SEC) for the studies of paper degradation phenomena. The goal is to solve some of the technical problems connected with the calibration of multi-detector SEC system and to find the correlation between SEC and viscometric results of degree of polymerization of cellulose. The results gathered for the paper samples degraded by acidic air pollutant (NO2) are used as an example of SEC–MALLS application. From the correlation between intrinsic viscosities and absolute value of molecular masses obtained with SEC/MALLS (Multi Angle Laser Light Scattering) technique, Mark-Houwink coefficients for cellulose in cupri-ethylenediamine solution were determined. Thus obtained coefficients were used for the determination of viscometric degree of polymerization (molecular mass) of the aged samples. An excellent correlation was found between the chromatographic values of molecular masses obtained with SEC–UV/VIS detection and the viscometric ones utilizing the improved values of Mark-Houwink coefficients. [ABSTRACT FROM AUTHOR]

Hydrolysis of cellulose in Whatman no. 42 cotton-based paper was studied using gel permeation chromatography (GPC), electrospray ionization-mass spectrometry (ESI-MS), and uniaxial tensile testing to understand the course and kinetics of the reaction. GPC results suggested that scission reactions passed through three stages. Additionally, the evolution of soluble oligomers in the ESI-MS data and the steady course of strength loss showed that the hydrolysis reaction occurred at a constant rate. These findings are explained with a more detailed description of the cellulose hydrolysis, which includes multiple chain scissions on amorphous segments. The breaks occur with increasing frequency near the ends of amorphous segments, where chains protrude from crystalline domains. Oligomers unattached to crystalline domains are eventually created. Late-stage reactions near the ends of amorphous segments produce a kinetic behavior that falsely suggests that hydrolysis had ceased. Monte Carlo simulations of cellulose degradation corroborated the experimental findings. [ABSTRACT FROM AUTHOR]

Abstract: The bacteria originated from the paper mill sludge were identified, isolated and cultured. Enterobacter (E) and Klebsiella (K) represented 70% of the culturable aerobic flora. Kinetics of EPS production in isolated culture and in arbitrary 1:1 mixture was investigated by high-pressure size exclusion chromatography (HPSEC). In isolated culture, Enterobacter produced regularly and gradually during 24h of culture, while Klebsiella produced the total amount of EPS already after 4h without any changes later. The chromatographic profiles of the EPS production of the 1:1 mixture after 4, 8 and 24h of culture could be fitted as a linear combination of the profiles of exopolymers produced by pure Enterobacter and Klebsiella strains. After 24h of culture, Enterobacter was predominant in term of population (82%) and produced about 77% EPS amount, in spite of competition phenomena observed during culture. [Copyright &y& Elsevier]

This study focuses on the temporal stability of insulation paper used in power transformers and intends to provide reliable and comprehensive estimators for the assessment of paper degradation state. To achieve the objectives artificially aged model papers were investigated along with power transformers insulation papers, by means of Size Exclusion Chromatography (SEC), Fourier-Transform Infrared Spectroscopy (FT-IR), ultraviolet–visible (UV–Vis) reflectance spectroscopy. The results of the UV–Vis analysis were compared to quantum chemical calculations performed by using time-dependent-Density Functional Theory method. The selection of methods allows the assessment of paper degradation state by characterization of depolymerisation progress and development of carbonyl groups. Our results not only are aimed to collect a data basis for paper condition assessment but also to increase the understanding of the mechanism of cellulose degradation in terms of relationship between aging conditions, different degradation paths and its observed effects. • Insulation paper degradation (oxidation and DP changes) described with use of spectroscopic and chromatographic techniques. • Concentration of chromophores in cellulose calculated from the UV–Vis spectra analysed by TDDFT simulations. • Transformer samples described by higher amount of conjugated diketones on C(2) and C(3) atoms than the aged model papers. • Two-indicator OI FTIR and DP approach is superior to one degradation indicator. [ABSTRACT FROM AUTHOR]

Because of its acidic and oxidative nature, iron gall ink promotes the endogenous degradation of paper manuscripts. Mechanical damage in areas of concentrated ink application or along mechanically stressed edges or folds results in problems during storage and handling. So far, such strongly degraded areas have usually been stabilized locally with thin Japanese paper and adhesives. A new and innovative material—nanocellulose—is being evaluated as a stabilizer for manuscripts that have been degraded by iron gall ink. The aim of this study is to integrate the nanocellulose application into a multi-stage calcium phytate/calcium hydrogencarbonate treatment to combine deacidification and stabilization, thus avoiding an additional stabilization and drying step. Two different types of fibrillated nanocelluloses were applied on manuscripts damaged by iron gall inks in different treatment steps. The newly formed, interlinked network of nanocellulose and paper was characterised before and after accelerated degradation in closed vials. The effects on the paper cellulose were studied by size exclusion chromatography and light scattering with carbonyl group profiling to follow cellulose hydrolysis and oxidation pathways. In addition, the migration behavior of iron ions was examined by laser ablation coupled with metal analysis (ICP-MS). This paper discusses the applicability and stability of nanocellulose on paper damaged by iron gall ink with regard to its long-term performance. Advantages and limitations are covered in detail. [ABSTRACT FROM AUTHOR]

This paper describes the synthesis of NIPU by using cardanol as starting material. A cardanol formaldehyde oligomer was first prepared through the reaction of cardanol and formaldehyde, catalyzed by citric acid. The resulting oligomer was then subjected to epoxidation with m-chloroperbenzoic acid to obtain an epoxide compound, which was subsequently used to fix carbon dioxide (CO2) and form a cyclic carbonate. Using this cyclic carbonate, along with an amine, cardanol-based isocyanate polyurethane (NIPU) was prepared. Different characterization methods, such as Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), and thermogravimetric analysis (TGA), were used to confirm the synthesis of the four intermediate products and NIPU in the reaction process. This study highlights the promise of bio-based NIPU as a sustainable alternative in a number of applications while offering insightful information on the synthesis and characterization of the material. [ABSTRACT FROM AUTHOR]

In this paper, a state-of-the-art multi-detection gel permeation chromatography/size exclusion chromatography (GPC/SEC) system including multi-angle laser light scattering (MALLS) is applied to monitor radiation-induced synthesis of internally crosslinked nanostructures from poly(acrylic acid) (PAA). The aim is to demonstrate that this modern tool yields a more detailed picture of reaction mechanism and product structure than the techniques used to date. The prevailing intramolecular crosslinking narrows the molecular weight distribution from Mw/Mn = 3.0 to 1.6 for internally crosslinked structures. A clear trend from over 0.7 to 0.5 in the Mark–Houwink exponent and a decrease in Rg/Rh from 1.7 to 1.0 point to the formation of nanogels, more rigid and less permeable than the starting coils. Changes in the coil contraction factor (g′ = [η]irradiated/[η]linear) as a function of the radical density revealed the existence of two modes in intramolecular crosslinking, the initial one (up to 0.075 radicals per monomer unit) where the compactness of products changes strongly with progressing crosslinking and a second one where further compacting is suppressed by the lower flexibility of the partially crosslinked chain segments. This indicates a transition from soft, still internally crosslinkable nanogels to more rigid structures, less prone to further intramolecular loop formation. Our findings provide means for the tailored design of new PAA nanomaterials. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study investigating the biodegradation of poly(butylene succinate) (PBS)/wheat bran (WB) biocomposites. Injection mouldings were subjected to biodegradation in compost-filled bioreactors under controlled humidity and temperature conditions. The effects of composting time (14, 42 and 70 days) and WB mass content (10%, 30% and 50% wt.) on the structural and thermal properties of the samples were investigated. Measurements were made by infrared spectral analysis, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and gel permeation chromatography. Results demonstrated that both the thermal and structural properties of the samples depended greatly on the biodegradation time. Specifically, their crystallinity degree increased significantly while molecular mass sharply decreased with biodegradation time, whereas their thermal resistance only showed a slight increase. This resulted from enzymatic hydrolysis that led to the breakdown of ester bonds in polymer chains. It was also found that a higher WB content led to a higher mass loss in the biocomposite samples during biodegradation and affected their post-biodegradation properties. A higher bran content increased the degree of crystallinity of the biocomposite samples but reduced their thermal resistance and molecular mass. [ABSTRACT FROM AUTHOR]

The objective of this paper is to analyze and contrast the features of the structure of jujube polysaccharides extracted and purified using various techniques, four fractions, namely hot water extraction and 0.3 M NaCl‐PBS purification (PZMP3‐1 and PZMP3‐2), alkaline extraction and 0.3 M NaCl purification (SAZMP4), alkaline extraction and 0.3 M‐PBS NaCl purification (PZJRP), are obtained by column chromatography (Sephacryl S‐300) and Fast Flow (DEAE‐Sepharose). Chemical testing, gas chromatography, scanning electron microscopy, nuclear magnetic resonance spectroscopy, methylation analysis, high‐performance gel permeation chromatography, and atomic force microscopy are used to examine and evaluate their properties. Different purification methods have certain effects on the structural characteristics of a series of jujube polysaccharides. The results can provide fundamental knowledge to select desirable extraction and purification technologies for the preparation of pure jujube polysaccharides. [ABSTRACT FROM AUTHOR]

Biobased plastics have the potential to be sustainable, but to explore their circularity further, current end-of-life options need to be broadened. Mechanical recycling is one of the most accepted methods to bring back plastics into the loop. Polyhydroxybutyrates (PHBs) are biobased and biodegradable in nature with promising properties and varied applications in the market. This study focuses on their potential for mechanical recycling by multiple extrusion cycles (E1–E5) and multi-faceted characterization of the virgin (V) and reprocessed materials from E1 to E5. The behavior is compared to polypropylene (PP) as a reference with a similar property profile, which has also been reprocessed five times. The thermal properties of both series showed a stable melting point and thermal decomposition temperature from thermal analyses (differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)). However, a steady increase in the degree of crystallinity was observed which could counterbalance the decrease in molecular weight due to repeated extrusion measured by gel permeation chromatography and resulted in similar values of tensile strength across the cycles. The strain at break was impacted after the first extrusion, but no significant change was observed thereafter; the same was observed for impact strength. Even in scanning electron microscopy (SEM) images, virgin and E5 samples appeared similar, showing the stability of morphological characteristics. Fourier transform infrared spectroscopy (FTIR) results revealed that no new groups are being formed even on repeated processing. The deviation between the PHB and PP series was more predominant in the melt mass flow rate (MFR) and rheology studies. There was a drastic drop in the MFR values in PHB from virgin to E5, whereas not much difference was observed for PP throughout the cycles. This observation was corroborated by frequency sweeps conducted with the parallel plate method. The viscosity dropped from virgin to E1 and E2, but from E3 to E5 it presented similar values. This was in contrast to PP, where all the samples from virgin to E5 had the same values of viscosity. This paper highlights the possibilities of mechanical recycling of PHB and explains why future work with the addition of virgin material and other additives is an area to be explored. [ABSTRACT FROM AUTHOR]

This work evaluates the effect of using selected inorganic chemicals as the main components of waterborne wood preservative systems on the degradation of the cellulose constituent in wood from model samples. The polymeric properties of cellulose and the homogeneity of the degradation process primarily reflect very well the degree of cellulose deterioration. Whatman papers, as pure cellulose model samples, were impregnated with 10 different 5 wt% solutions of inorganic salts and distilled water and consequently subjected to wet-thermal accelerated aging (T = 85 °C, RH = 65%, for 30 days). The samples were then derivatized to cellulose tricarbanilates (CTCs) through two different procedures (by precipitation in a methanol–water mixture/by evaporation of pyridine from the reaction mixture) and finally analyzed using size exclusion chromatography (SEC). Chemically treated and aged cellulose samples showed different changes in the degree of polymerization (DP) and polydispersity (PD) in terms of untreated non-aged standard caused by different ongoing degradation reactions, such as dehydration, hydrolysis, oxidation, and crosslinking. In general, the lowest degradation rate after treatment by chemicals and after accelerated aging was observed in samples treated by borates, NaCl, and ZnSO4·7H2O. The greatest depolymerization after treatment and after accelerated aging was caused by sulphates containing NH4+, Cu2+, and Fe3+ cations, with aging by NH4Cl and (NH4)2HPO4-treated samples also leading to significant depolymerization. The higher DP values are linked to the precipitated method of CTC preparation, though not for chlorides and phosphates. PD is also generally higher in precipitated and aged samples and is heavily influenced by the presence of low molecular weight products. This paper brings new insights regarding the complex evaluation of the polymeric properties of degraded cellulose by considering all important factors affecting the sample and the analysis itself through the use of statistics. From the statistical point of view, the influences of all factors (solution, aging, method) and their interactions (except aging*method) on DP are statistically significant. The influence of the sample processing method used for analysis of the desired results becomes important mainly in practice. This work recommends the evaporation method for more accurate description of more degraded cellulose. [ABSTRACT FROM AUTHOR]

The application of recycled fibers is steadily increasing in various paper products recently. It is necessary to improve the mechanical properties of paper products made from these fibers. An eco-friendly polymeric additive, sodium alginate (SA), was prepared from waste seaweeds and developed as functional additives. The properties of SA were characterized by proton nuclear magnetic resonance, Fourier transform infrared spectroscopy, thermal gravity analysis, gel permeation chromatography, and compared with the commercial SA. Coupled with polyamideamine-epichlorohydrin (PAE), the extracted SA was used to enhance the mechanical properties of paper from recycled fibers. The surface and cross-section morphology of the paper were measured by scanning electron microscopy and discussed. Compared with the single addition of PAE, the SA-PAE binary system significantly improved the mechanical properties of paper sheets. [ABSTRACT FROM AUTHOR]

Salt-erosion effect can significantly deteriorate the serviceability of asphalt pavements in salt-rich regions. This paper aims to analyze the creep characteristics and the evolution mechanism of asphalt binder/mastic under salt-erosion conditions. The multi-stress creep recovery (MSCR) test and bending beam rheology (BBR) test were conducted to investigate the creep evolution of salt-eroded asphalt binder/mastic under different temperatures. The gel permeation chromatography (GPC) and scanning electron microscopy (SEM) were employed to analyze the creep evolution mechanism of salt-eroded asphalt binder/mastic. Furthermore, the Burgers model and Schapery model were adopted to study the viscoelastic characteristic evolution of salt-eroded asphalt binder/mastic. Results indicated that the proportion of small molecules in asphalt binder was declined, and the mineral filler coated with asphalt binder was exposed, after salt erosion. The nonrecoverable deformation of asphalt binder/mastic at high- and medium-temperature were reduced after salt erosion. Meanwhile, the percentage of recoverable strain increased with the salt freeze-thaw cycles. The low-temperature performance of asphalt binder/mastic was deteriorated after salt erosion. Following 20 times of salt erosion, the stiffness modulus of asphalt binder/mastic increased by 59.77 % and 16.47 %, respectively. Meanwhile, salt erosion can decrease the viscous components in asphalt binder/mastic, the comprehensive compliance (J c) of asphalt binder/mastic increased by 59.65 % and 16.93 %. Furthermore, the asphalt binder-mineral filler interaction was weakened after salt erosion, the Einstein coefficient decreased by an average of 18.52 %. The design and construction of asphalt pavement in salt-rich regions might be benefited from this paper. • Evaluate the creep characteristics of salt-eroded asphalt binder/mastic. • Investigate the evolution of salt-eroded asphalt binder-filler interaction. • Clarify the creep evolution mechanism of salt-eroded asphalt binder/mastic. [ABSTRACT FROM AUTHOR]

This paper investigates the significance of element speciation analysis, the various hyphenated techniques used in element speciation analysis, and their application in real samples. This involves a variety of separation technologies, such as high-performance liquid chromatography, ion chromatography, size exclusion chromatography, gas chromatography, and capillary electrophoresis, as well as various detection methods, such as inductively coupled plasma mass spectrometry, inductively coupled plasma optical emission spectrometry, atomic fluorescence spectrometry, and atomic absorption spectrometry. Based on this, we developed teaching experiments, combined theory with practice, and further strengthened students' understanding, mastery, and application of knowledge. [ABSTRACT FROM AUTHOR]

The goal of this paper is to analyze the aging behavior and the mechanism evolution of nano-Al2O3 (NA)-reinforced styrene-butadiene-styrene (SBS) asphalt under different thermal-oxidative aging conditions. First, NA/SBS-modified asphalt and SBS-modified asphalt with different aging levels were prepared. Second, the viscosity and high temperature rheological performance of the specimens were tested and the property-related aging indexes were calculated and compared. Third, a Fourier transform infrared (FTIR) test of the specimen was conducted and the chemical group-related aging indexes were calculated and analyzed. Fourth, gel permeation chromatography (GPC) was used to analyze the molecular weight of the specimens under different aging levels. Then, an atomic force microscope (AFM) was adopted to analyze the microsurface morphology of different specimens. Finally, correlation analysis between property-related indexes and chemical group indexes was conducted. The results show that NA can enhance the thermal-oxidative aging resistance of SBS asphalt. NA can inhibit the increase in sulfoxide groups and the degradation of the SBS polymer with the increase in aging. NA can slow down the formation of large molecule during the aging process. The degree of change in both the bee structures and micromorphological roughness of NA/SBS asphalt is lower than that of SBS asphalt under different aging levels. [ABSTRACT FROM AUTHOR]

In this article, three new poly(1,2,3-triazolyl-benzenesulfonamide)s (4-6) were synthesized from the new molecule 4-azido-N-(prop-2ʹ-yn-1ʹ-yl)benzenesulfonamide (3). The synthesis and step-growth click polyaddition reaction of a new AB-type monomer containing terminal alkyne and azide groups were described. Copper (I)-catalyzed azide-alkyne cycloaddition (CuAAC) and Huisgen click polymerization were performed to prepare sulfonamide, a derivative of poly(1,2,3-triazole)s. The CuAAC polymerization regioselectively led to 1,4-disubstituted triazole ring and hence to a stereoregular polymer. In contrast, the thermal polymerization also produced 1,5-disubstituted triazole units. The structure of the new poly(1,2,3-triazolyl-benzenesulfonamide)s (4-6) obtained from (4-azido-N-(prop-2ʹ-yn-1ʹ-yl)benzenesulfonamide) were characterized by FTIR, 1H-, and 13C- NMR spectroscopy. The resulting polymers had weight-average molecular weights in the 7,700-58,650 range and were determined by Gel Permeation Chromatography (GPC). The resulting polymers 4, 5 and 6, lossing about 50% of their weights, showed a decomposition temperature of 406, 474, and 451 °C in a nitrogen atmosphere, respectively. The glass transition temperature of all polymers were at 128 °C. In addition, the surface morphology was studied via Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS). This paper is dedicated to the 100th Anniversary of the Republic of Türkiye. [ABSTRACT FROM AUTHOR]

The paper reports a facile synthesis of novel anionic spherical polymer brushes which was based on grafting sodium 2-acrylamido-2-methylpropane-1-sulfonate from the surface of 4,4′-Azobis (4-cyanopentanoyl chloride)-modified carbon spheres. Various characterization methods involving a scanning electron microscope, energy dispersive X-ray spectroscopy, Fourier transform infrared spectrum, and thermo-gravimetric analysis were utilized to analyze the morphology, chemical composition, bonding structure, and thermal stability, respectively. The molecular weight (Mw) and polydispersity (Mw/Mn) of brushes were 616,000 g/mol and 1.72 determined by gel permeation chromatography experiments. Moreover, the dispersibility of ASPB in water and in the presence of aqueous NaCl solutions of different concentrations was investigated. Results show that the dispersibility of carbon spheres has been enhanced owing to grafted polyelectrolyte chains, while the zeta potential of the particle decreases and its brush layer shrinks upon exposure to sodium ions (Na+). [ABSTRACT FROM AUTHOR]

Styrene-butadiene rubber (SBR) modified asphalt (SBRMA) can exhibit a good low-temperature performance. However, exposure to high-temperature and oxygen-containing environment can easily lead to decomposition of SBR modifier during the pavement construction process, which seriously compromises the modifying effects endowed by SBR modifier. To mitigate the negative influence of short-term aging on the performance of SBRMA, the warm-mix additive Sasobit was added into SBRMA due to its role in reducing mixing temperatures of asphalt mixture. In this paper, the mixing temperature of asphalt mixture was determined based on equal viscosity principle and set as short-term aging temperature of corresponding asphalt binder. The effect of Sasobit on the short-term aging temperature of the asphalt binder was further evaluated. In addition, the effects of Sasobit on un-aged and short-term aged SBRMA were investigated by physical, rheological, infrared spectrum, fluorescence microscopy and gel permeation chromatography tests. The results indicated the addition of Sasobit can effectively reduce the short-term temperature of SBRMA by 14 ºC through its effect of reducing viscosity. And the addition of Sasobit can improve the high-temperature stability of SBRMA but decrease its low-temperature ductility. The reduced short-term temperature due to adding Sasobit can mitigate the negative influence of short-term aging on SBRMA and SBR modifiers through physical and rheological aging indexes, chemical functional group, fluorescent images and polymer molecular weight evaluation. [ABSTRACT FROM AUTHOR]

Dust palliatives are commonly used when airborne dust is problematic. Dry soils are treated with a mixture of polymers, such as butyl acrylate vinyl acetate (BA–VA), emulsified in water. Eventual spread through surface runoff or leaching may transport palliative away from the application area. This paper reports a novel method developed for the determination of BA–VA using gel permeation chromatography (GPC) and nuclear magnetic resonance spectroscopy (1H NMR) to provide qualitative and quantitative measurements allowing further investigation of polymer-based soil palliatives. The results showed that the average specific refractive index increments (dn/dc) for BA–VA copolymer in two dust palliatives were 0.055 and 0.038 mL/g. The masses of extracted BA–VA were 1400 and 2900 mg from these products. The corresponding limits of quantification (LOQ) for the extracted BA–VA polymer using a refractive index (RI) detector were 11.63 and 17.04 µg, respectively. [ABSTRACT FROM AUTHOR]

The synthesis of cationic polyacrylamides (CPAMs) with the desired cationic degree and molecular weight is essential for various industries, including wastewater treatment, mining, paper, cosmetic chemistry, and others. Previous studies have already demonstrated methods to optimize synthesis conditions to obtain high-molecular-weight CPAM emulsions and the effects of cationic degrees on flocculation processes. However, the optimization of input parameters to obtain CPAMs with the desired cationic degrees has not been discussed. Traditional optimization methods are time-consuming and costly when it comes to on-site CPAM production because the input parameters of CPAM synthesis are optimized using single-factor experiments. In this study, we utilized the response surface methodology to optimize the synthesis conditions, specifically the monomer concentration, the content of the cationic monomer, and the content of the initiator, to obtain CPAMs with the desired cationic degrees. This approach overcomes the drawbacks of traditional optimization methods. We successfully synthesized three CPAM emulsions with a wide range of cationic degrees: low (21.85%), medium (40.25%), and high (71.17%) levels of cationic degree. The optimized conditions for these CPAMs were as follows: monomer concentration of 25%, content of monomer cation of 22.5%, 44.41%, and 77.61%, respectively, and initiator content of 0.475%, 0.48%, and 0.59%, respectively. The developed models can be utilized to quickly optimize conditions for synthesizing CPAM emulsions with different cationic degrees to meet the demands of wastewater treatment applications. The synthesized CPAM products performed effectively in wastewater treatment, with the treated wastewater meeting the technical regulation parameters. 1H-NMR, FTIR, SEM, BET, dynamic light scattering, and gel permeation chromatography were employed to confirm the structure and surface of the polymers. [ABSTRACT FROM AUTHOR]

To clarify the effect of NaCl concentration (0–2.0%) on the formation of amyloid fibrils (AFs) in cooked wheat noodles, the morphology, surface hydrophobicity, secondary structure, molecular weight distribution, microstructure, and crystal structure of AFs were investigated in this paper. Fluorescence data and Congo red stain images confirmed the presence of AFs and revealed that the 0.4% NaCl concentration promoted the production of AFs. The surface hydrophobicity results showed that the hydrophobicity of AFs increased significantly from 3942.05 to 6117.57 when the salt concentration increased from 0 to 0.4%, indicating that hydrophobic interactions were critical for the formation of AFs. Size exclusion chromatography combined with gel electrophoresis plots showed that the effect of NaCl on the molecular weight of AFs was small and mainly distributed in the range of 5–7.1 KDa (equivalent to 40–56 amino acid residues). X-ray diffraction and AFM images showed that the 0.4% NaCl concentration promoted the formation and longitudinal growth of AFs, while higher NaCl concentrations inhibited the formation and expansion of AFs. This study contributes to the understanding of the mechanism of AF formation in wheat flour processing and provides new insight into wheat gluten aggregation behavior. [ABSTRACT FROM AUTHOR]

In this work, polyvinyl butyral (PVB) with number-average molecular weight of 35,700 g mol−1 and butyraldehyde content of 78.66% was synthesized, and was characterized by Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), derivative thermogravimetric analysis (DTG) and pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS). The results showed that the prepared PVB has high degree of acetalization and high thermal stability. Hansen solubility parameters (HSPs) of PVB were determined by HSPiP software, turbidimetric titration, intrinsic viscosity method and group contribution method. The Flory–Huggins interaction parameters (χ and χHSP) between PVB and solvents were calculated, and the results showed that the intrinsic viscosity [η] increased linearly with the decrease of χ and χHSP values. Both the graph of [η] versus χ and the graph of [η] versus χHSP can be divided into dissolving area and nondissolving area by χ = 0.5 and χHSP = 0.5, which fully proved that the HSPs obtained in this paper were convincing. It is expected that these parameters are available for predicting the solubility of PVB in various solvents and the compatibility with additives. [ABSTRACT FROM AUTHOR]

The paper studies thermal characteristics of new polycarbonates obtained using the bisphenol A-free technology. Thermal tests of polycarbonates were carried out in a wide temperature range using the DSC (diffrential scanning calorimetry) and TG (thermogravimetry) analyses. The DSC data confirmed that all materials are homogeneous whereas the endothermic peaks are responsible for melting. Additionally, the analysis of the released gases was made by means of the infrared spectroscopic analysis. Our research proved that the new polycarbonates are relatively heat resistant. In the range of the thermal destruction of the studied materials there can be considered, two types of degradation reactions. The first step around 200 °C and the second one around 300 °C. Gel permeation chromatography were performed to determined molar masses of polymers. XRD analysis showed that the obtained polycarbonates showed a partially crystalline structure. [ABSTRACT FROM AUTHOR]

Presently, society needs an eco-friendlier alternative for non-biodegradable polymers, nonetheless, synthetic polymers have established the market because of cost and easy to manufacture. To address the challenge of reducing the lifetime of degradation of these polymers, the scope of blending natural biopolymers is effective. This paper focuses on confirming the effectiveness of biodegradation in the molecular level of polymer blends between synthetic polymers and biopolymers. The synthetic polymers such as poly (methyl methacrylate) (PMMA) and poly (vinyl chloride) (PVC) were blended with varying compositions of biodegradable cellulose acetate butyrate (CAB). Using dimethylformamide (DMF) the films of PMMA/CAB, PVC/CAB blends were prepared by the solution casting method. Four different methods for studying biodegradability of these blends, namely soil burial test, enzymatic degradation, activated sludge degradation followed by microbial degradation were performed. The confirmation of degradation was done by NMR, FTIR, and Gel Permeation Chromatography (GPC) studies. Moreover, degradation analyses were determined by the weight loss method. Sufficient biodegradability was shown with an increase in CAB content in the blend. This work provides an approach for bringing about the degradation of synthetic polymers without much compromise on their properties. Also, the type of microorganisms that effectively degrades these polymer bends can be known. [ABSTRACT FROM AUTHOR]