Gel Permeation Chromatography Research Articles

Preparation of Polydimethylsiloxane Copolymers by the Azide–Alkyne Huisgen Cycloaddition Method

The copolymers containing alternating siloxane and urethane units in the chain as well as ester moieties were synthesized by the azide–alkyne cycloaddition without application of a solvent and copper salts as catalysts. The resulting copolymers were analyzed by NMR spectroscopy and gel permeation chromatography.

Facile synthesis of polyester-polyether block copolyols for the sustainable high-performance polyurethane reactive hot melt adhesives

The presence of polyols with both polyester and polyether structures in polyurethane enhances bonding strength and facilitates easy curing. In this study, polyester-polyether block polyols with varying molecular weights (2500–3500) were synthesized through ring-opening polymerization (ROP) using l-lactide (LA) and ε-Caprolactone (CL). The chemical structure of the polyols was characterized using 1H nuclear magnetic resonance (1H NMR), Fourier transform infrared (FTIR), and gel permeation chromatography (GPC). Differential scanning calorimetry (DSC) and polarized optical microscopy (POM) were employed to examine the crystalline morphology of the polyols. Subsequently, the synthesized polyols were combined with 4,4′-diphenylmethane diisocyanate (MDI) and other additives to prepare polyurethane reactive hot melt adhesives. It was observed that, in PCL-based polyurethane reactive hot melt adhesives, increasing the molecular weight of the polyols resulted in improved crystalline morphology, increased lap shear strength and tensile strength, and enhanced thermal stability. On the other hand, PLA-based polyurethane reactive hot melt adhesives exhibited low bonding strength and lacked practical application value due to the poor toughness of PLA. Interestingly, the bonding strength and tensile strength of PLA-based polyurethane reactive hot melt adhesives improved when physically blended with PCL-based polyurethane reactive hot melt adhesives. These polyols offer a novel approach for utilizing LA and CL in adhesive applications.

Preparation of Allyl-Containing PDMS Telehelics by the Anionic Ring-Opening Polymerization

The synthesis of allyl-containing PDMS telechelics from octamethylcyclotetrasiloxane and 1,3-diallyl-1,1,3,3-tetramethyldisiloxane as a stopper by the anionic ring-opening of a siloxane ring is presented. A series of the polymers with the molecular weights from 1000 to 12000 were obtained and characterized by gel permeation chromatography and 1H NMR spectroscopy. The molecular weights of the resulting polymers correspond to the given ones.

Dual-Self-Crosslinking Effect of Alginate-Di-Aldehyde with Natural and Synthetic Co-Polymers as Injectable In Situ-Forming Biodegradable Hydrogel.

Injectable, in situ-forming hydrogels, both biocompatible and biodegradable, have garnered significant attention in tissue engineering due to their potential for creating adaptable scaffolds. The adaptability of these hydrogels, made from natural proteins and polysaccharides, opens up a world of possibilities. In this study, sodium alginate was used to synthesize alginate di-aldehyde (ADA) through periodate oxidation, resulting in a lower molecular weight and reduced viscosity, with different degrees of oxidation (54% and 70%). The dual-crosslinking mechanism produced an injectable in situ hydrogel. Initially, physical crosslinking occurred between ADA and borax via borax complexation, followed by chemical crosslinking with gelatin through a Schiff's base reaction, which takes place between the amino groups of gelatin and the aldehyde groups of ADA, without requiring an external crosslinking agent. The formation of Schiff's base was confirmed by Fourier-transform infrared (FT-IR) spectroscopy. At the same time, the aldehyde groups in ADA were characterized using FT-IR, proton nuclear magnetic resonance (¹H NMR), and gel permeation chromatography (GPC), which determined its molecular weight. Furthermore, borax complexation was validated through boron-11 nuclear magnetic resonance (¹¹B NMR). The hydrogel formulation containing 70% ADA, polyethylene glycol (PEG), and 9% gelatin exhibited a decreased gelation time at physiological temperature, attributed to the increased gelatin content and higher degree of oxidation. Rheological analysis mirrored these findings, showing a correlation with gelation time. The swelling capacity was also enhanced due to the increased oxidation degree of PEG and the system's elevated gelatin content and hydrophilicity. The hydrogel demonstrated an average pore size of 40-60 µm and a compressive strength of 376.80 kPa. The lower molecular weight and varied pH conditions influenced its degradation behavior. Notably, the hydrogel's syringeability was deemed sufficient for practical applications, further enhancing its potential in tissue engineering. Given these properties, the 70% ADA/gelatin/PEG hydrogel is a promising candidate and a potential game-changer for injectable, self-crosslinking applications in tissue engineering. Its potential to revolutionize the field is inspiring and should motivate further exploration.

Disulfide stoppered polyrotaxanes with enhanced cellular uptake and intracellular cyclodextrin release

Background and AimPolyrotaxanes are molecular necklaces composed of polymers, threaded macrocycles, and bulky stopper molecules to inhibit the decomposition of the first two. These supramolecular assemblies are promising active ingredients for treating lysosomal storage disorders. This study aimed to synthesize such polyrotaxanes with a novel, simple method, resulting in high threading efficacy, enhanced cellular uptake, and intracellular cyclodextrin (CD) release. MethodsIn this study, we developed two novel poly(ethylene glycol) (PEG) based polyrotaxanes, with threaded α-cyclodextrin (α-CD) or its mixture with 2-hydroxypropyl-α-CD (HP-α-CD) and glutathione sensitive disulfide connected stopper molecules. The structure and composition of these polyrotaxanes were determined by 1H NMR spectroscopy and gel permeation chromatography, while the cellular uptake was investigated by flow cytometry and confocal microscopy. ResultsHigh threading efficacy, as well as molar mass of 17.9 and 13.1 kDa, was found for the polymeric supramolecules with threaded α-CD and α-CD/HP-α-CD, respectively. Glutathion-triggered reductive removal of the stopper molecules showed potential decomposition of these polyrotaxanes in target cells. Flow cytometry revealed an up to 52-fold enhancement in cellular uptake of α- and HP-α-CD by the polyrotaxanes compared to free CD, which was also visualized by confocal microscopy. Conclusion and scope of applicationPolyrotaxanes based on α-CD and its derivative were tested in vitro for application in the treatment of lysosomal storage disease for the first time. Based on these results, polyrotaxanes with disulfide stopper molecules might be promising supramolecular excipients for cellular delivery of α-CDs.

The Effects of Ester and Ether Polycarboxylate Superplasticizers on the Fluidity and Setting Behavior of Alkali-Activated Slag Paste.

This study aims to investigate the comparative performance of ester- and ether-based polycarboxylate superplasticizers in maintaining the fluidity and controlling the setting time of alkali-activated slag (AAS) paste. The experiments employed rheological tests, mini-slump tests, ultrasonic pulse velocity (UPV) measurements, and gel permeation chromatography (GPC) analysis. The results indicate that ether-based superplasticizers maintain fluidity approximately 25% longer than their ester-based counterparts and extend the setting time by about 30%. The enhanced performance of ether-based superplasticizers is attributed to their superior molecular stability in highly alkaline environments, which mitigates early polymer degradation. Additionally, the Na2O/SiO2 ratio was maintained at 1:1 throughout the experiments to ensure consistency in the activation process. The relationship between fluidity loss and the onset of setting occurs more rapidly in AAS paste than in conventional cement-based systems. These findings provide valuable insights for the development of environmentally friendly construction materials by optimizing the use of superplasticizers in alkali-activated systems.

Effect of carbodiimides on the compatibility and hydrolytic behavior of PLA/PBAT blends

Blends of polylactic acid (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) have great potential to replace conventional polyolefin and polyester materials. However, poor compatibility and fast degradation rate limit its development. In this paper, the effects of two monomer-type carbodiimides and one polymerized carbodiimide on the crystalline, thermal stability, hydrolysis properties, and mechanical properties of PLA/PBAT blends are investigated by Fourier transform infrared spectroscopy, scanning electron microscope, differential scanning calorimetry, thermogravimetric analysis, gel permeation chromatography, melt mass-flow rate, terminal carboxyl content, tensile properties, and rotational torque. It is found that all the three carbodiimide additives can improve the compatibility and enhance the mechanical, processing, and thermal stability properties of PLA/PBAT blends except for their reduced crystallization performance. Moreover, regarding the hydrolysis properties, the two monomeric carbodiimides exhibit little effect on the hydrolysis of PLA/PBAT blends, even accelerating the degradation rate under alkaline conditions. However, the antihydrolysis effect of polycarbodiimide is remarkable, which effectively improves the compatibility and antihydrolysis properties of PLA/PBAT blends.

Lactobacillus fermentum SNR1: Probiotic efficiency and characterization of the antimicrobial peptide against dental caries and foodborne pathogens

In this study, fermented rice gruel, a traditional food in South Telangana, India, was used as a source for the isolation of biologically significant probiotics. A total of 56 morphologically diverse strains were isolated and screened for their ability to inhibit dental biofilms as well as foodborne and aquaculture bacterial pathogens. Among these, isolate SNR1 was selected for further characterization due to its potential antimicrobial activity against bacterial pathogens such as Streptococcus mutans, Listeria monocytogenes, Staphylococcus aureus, Vibrio parahaemolyticus and Salmonella typhi. The results of 16S rDNA sequencing showed that isolate SNR1 was closely related to Lactobacillus fermentum strains from different sources. The bacteriocin peptide with potential activity was extracted and purified from the cell-free supernatant using ammonium sulphate precipitation, gel permeation chromatography and reversed-phase high performance liquid chromatography (RP-HPLC), and was named peptide SNR1. Tricine SDS-PAGE followed by MALDI-TOF-MS analysis revealed that the purified peptide had a molecular mass of 4.33 kDa, with the N-terminal sequence identified as MPTTSHFHLSPQGK. The purified peptide SNR1 showed good stability with various physiological enzymes, temperatures and pH conditions.

Advancing Sustainability: Geraniol-Enhanced Waterborne Acrylic Pressure-Sensitive Adhesives without Chemical Modification.

The escalating global emphasis on sustainability, coupled with stringent regulatory frameworks, has spurred the quest for environmentally viable alternatives to petroleum-derived materials. Within this context, the adhesives industry has been actively seeking renewable options and eco-friendly synthesis pathways. This study introduces geraniol, a monoterpenoid alcohol, in its unmodified form, as a key component in the production of waterborne pressure-sensitive adhesives (PSAs) based on acrylic latex through emulsion polymerization. Multiple formulations were developed at varying reaction times. The adhesives underwent comprehensive chemical characterization employing techniques such as Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Nuclear Magnetic Resonance (NMR), Gel Permeation Chromatography (GPC), and dynamic light scattering (DLS). The viscosities of the formulations were measured between 4000 and 5000 cP. Adhesion tests showed peel strength values of 0.52 N/mm on cardboard and 0.32 N/mm on painted steel for the geraniol-based formulations. The results demonstrate the potential for geraniol-based PSAs to offer a sustainable alternative to petroleum-derived adhesives, with promising thermal and adhesive properties.

Low-Foaming Nonionic Gemini Surfactants Containing Hydrophilic Poly(oxyethylene) Chain and Hydrophobic Di-tert-pentylbenzenes Groups.

Low-foaming nonionic gemini surfactants have a wide range of applications in industrial cleaning and photoresist development. In this study, three low-foaming nonionic gemini surfactants (S1, S2, and S3) with different poly(oxyethylene) chain lengths have been synthesized by using methoxy poly(ethylene glycol) and 2,5-di-tert-pentylhydroquinone. The chemical structures of the novel surfactants are confirmed by 1H NMR, Fourier transform infrared, and gel permeation chromatography (GPC), and their properties such as surface tension, wetting properties, emulsifying properties, and foaming properties are investigated. The surface tension values of S1, S2, and S3 at the critical micelle concentration are 40.29, 37.14, and 41.64 mN/m, exhibiting good surface activity. When the surfactant concentration is higher than 2 mM, the contact angles of S1 and S2 no longer change and can maintain 62 and 64°, showing good wetting properties. In addition, S3 can keep an emulsion state for 2 months at high concentrations, exhibiting good emulsion stability. Furthermore, all the prepared surfactants show good low-foaming properties. The initial foaming volumes of S1 are very low, less than 0.1 mL at various concentrations, less than 2% of the conventional surfactant sodium dodecyl sulfate. For S2, the initial foaming volumes at the concentration of 0.1, 1, 2, and 3 g/L are 1, 0.5, 0.55, and 0.45 mL, respectively. For S3, the initial foaming volumes show a general trend of increasing with concentration. The surfactants with longer poly(oxyethylene) chains possess more initial foaming volumes at the same concentration, which is because the greater cohesion between the surfactant molecules can increase the elasticity of the bubble film. Our study enriches the design rationales for low-foaming surfactants and motivates researchers to develop more advanced surfactants for industrial cleaning and photoresist development.

Manufacture of Solid Propellants Based on Renewable Succinic Acid Polyols

AbstractModern energy policies encourage the replacement of fossil fuels with a more sustainable type. Succinic acid is a promising renewable material that can react with ethylene glycol and 1,4‐butanediol in a two‐step polycondensation reaction to form hydroxylated polyesters. Copolymerization reactions were investigated to produce novel green binders for manufacture of solid propellants. The ester of the first step of polycondensation was used as a plasticizer in the propellant formulation. These products can be an alternative to binders of fossil sources, such as hydroxyl‐terminated polybutadiene (HTPB), frequently used as fuel of commercial propellants. Initially, analyses of Fourier transform infrared spectroscopy, nuclear magnetic resonance and gel permeation chromatography indicated the formation of polymeric products and adequate chain growth at reaction conditions. Then, the obtained copolymers were characterized by rheological analyses, which revealed that the processability of the copolymer materials was similar to that of the HTPB samples. Additionally, thermogravimetric analyses indicated that the copolymers presented good thermal stability below 200°C. Furthermore, differential scanning calorimetric (DSC) analyses indicated that the glass transition temperatures of the obtained copolymer samples ranged from −20 to −60°C, a suitable range for the intended use. Solid propellants were then prepared with solid loadings above 70 wt %, heat of combustion above 11,300 J g−1 and heat of explosion above 4,980 J g−1, which are compatible with values expected for solid propellants. Finally, oxygen balance calculations showed that the intrinsic oxygen content of the polyesters can allow the reduction of amounts of oxidizers in the final propellants.

Waste coffee biochar and bi-oil composite modified rejuvenated asphalt: Preparation, characterization, and performance evaluation

In the realm of sustainable road construction, bio-oil has emerged as a promising and eco-friendly alternative for rejuvenating aged asphalt. Nevertheless, challenges arise due to poor stability, diminished performance at elevated temperatures, and limited anti-aging properties. This study introduces an innovative approach by blending biochar, obtained from the pyrolysis of waste coffee grounds, into bio-oil to create a composite modified regenerator. Initially, the study conducts a microscopic characterization of the biochar using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Subsequently, the rheological properties of this composite rejuvenated asphalt are evaluated across low, moderate, and high-temperature ranges using bending beam rheometer (BBR), linear amplitude sweep (LAS), and multiple stress creep and recovery (MSCR) tests. Departing from the traditional emphasis on initial property restoration, it further delves into performance alterations after re-aging of rejuvenated asphalt through temperature sweep (TS) and Fourier transform infrared spectroscopy (FTIR) tests, providing a comprehensive assessment of the anti-aging characteristics of rejuvenated asphalt. Additionally, gel permeation chromatography (GPC) is employed to quantitatively analyze the changes in asphalt molecular weight distribution. The microscopic characterization reveals the development of a rough and porous structure within the biochar, facilitating enhanced adhesion and interaction between the rejuvenator and the asphalt binder. Moreover, bio-oil rejuvenated asphalt exhibits excellent low-temperature crack resistance and moderate-temperature fatigue resistance. Following the incorporation of biochar, notable enhancements in high-temperature rutting resistance and anti-aging properties are observed, validating the efficacy of the biochar with bio-oil composite modified regenerator. To achieve optimal performance outcomes, a biochar content of 6 % (as a proportion of aged asphalt), corresponding to a 1:1 ratio of biochar to bio-oil, is recommended. Under this condition, the properties of the composite modified rejuvenated asphalt demonstrate comparability to those of the original asphalt. In summary, this research underscores the potential for integrating waste coffee biochar material into infrastructure development, thereby promoting circular economy principles and advancing more sustainable construction practices.

Synthesis and Performance Evaluation of Metallocene Polyalphaolefins (mPAO) Base Oil with Anti-Friction and Anti-Wear Properties

Anti-wear and anti-oxidation abilities are two key properties of lubricants that play a crucial role in ensuring long-term stable equipment operation. In this study, we aimed to develop a base oil with good anti-oxidation and anti-wear properties for use under extreme pressure. The as-prepared metallocene polyalphaolefin (mPAO) was chemically modified using the trifluoromethanesulfonic acid (TfOH) catalysis through an alkylating reaction with triphenyl phosphorothioate (TPPT). During the experiments, when the reaction temperature exceeded 70 °C or the concentration of TfOH exceeded 2.67%, the β-scission reaction in the alkylation process became significantly more pronounced. The physical and chemical properties of TPPT-modified mPAO (T-mPAO) were evaluated by nuclear magnetic resonance spectroscopy, Fourier trans-form infrared spectroscopy, gel–permeation chromatography, and ASTM standards. T-mPAO showed significantly improved antioxidant capacity, with the initial oxidation temperature increasing by 32 °C compared to the base oil, and it exhibited the slowest increase in acid number in the 96-h oven oxidation test. The tribological tests showed that T-mPAO had the lowest friction coefficient, wear track, and wear rate (72.7% lower than that of mPAO) as well as the highest PB (238 kg) and PD (250 kg) among all tested samples. Compared to mPAO, the average friction coefficient of TPPT-modified mPAO in the four-ball friction test was reduced by 30.5%, and by 16.4% in the TE77 reciprocating friction test. Based on the experimental results, T-mPAO had strong anti-oxidation ability and excellent lubricating performance.The successful synthesis of multifunctional mPAO has enabled lubricant base oil additization, making it possible to use it in more demanding work scenarios, greatly broadening its application scope and making lubricant formulation blending more flexible.

Process Optimization and Characterization of Polysaccharides with Potential Antioxidant and Hypoglycemic Activity from Cissus repens.

Ultrasound-assisted extraction of Cissus repens polysaccharides (CRPs) was optimized through response surface methodology (RSM) based on Box-Behnken design (BBD). The maximum CRPs yield (16.18 %) was achieved under the optimum extraction conditions: extraction time 72 min, extraction temperature 74 °C, extraction power 240 W. Then three-phase partitioning (TPP) method combined with gradient alcohol precipitation was used to obtained CRP20, CRP40, CRP60 and CRP80 from CRPs, and CRP80 has a higher purity than others. The primary chemical and structural characteristics of CRP80 were investigated by UV, FT-IR, high-performance liquid chromatography (HPLC) and high-performance gel-permeation chromatography (HPGPC). CRP80 is mainly composed of glucose, galactose, arabinose and mannose, with a molecular weights of approximately 2.95 kDa. Furthermore, the antioxidant activity and hypoglyceamic activity of CRP80 in vitro were evaluated. The results showed that CRP80 had strong scavenging activities on ABTS, hydroxyl and DPPH radicals, as well as high scavenging activities on α-glucosidase and α-amylase. Our research provided an efficient method for the extraction of polysaccharides from C. repens and CRP80 has potential as a promising source of natural antioxidants and hypoglycemic agent for the functional food and medicinal industries.

Synthesis and optimization of molecular weight of chitosan and carboxymethyl cellulose based polyurethanes

For the first time in this research, using a mixture design approach, polyurethanes (PUs) based on chitosan (CSN) and carboxymethyl cellulose (CMC) were synthesized to develop a high molecular weight polymer. In the synthesis process, a reaction between isophorone diisocyanate (IPDI) and hydroxyl-terminated polybutadiene was carried out to synthesize a prepolymer containing free NCO groups at the corners. This prepolymer was further reacted with changing moles ratio of CSN and CMC following the principles of statistical mixture design. The structural confirmation of the developed PUs was carried out through spectroscopic techniques (FTIR and NMR). The molecular weights of the PU specimens were characterized using gel permeation chromatography. The findings demonstrated that the interaction between CMC and CSN led to a notable increase in the molecular weights of the samples, supported by a significant p-value of 0.006. Additionally, the analysis of variance (ANOVA) disclosed that the employed mixture design and the resulting interaction model effectively account for 98 % of the total variation observed in the molecular weights. The sample labeled as PUS-3 (CMC0.50:CSN0.50) emerged as the most significant formulation, exhibiting a noteworthy 27.9 % improvement in the polymer molecular weight compared to the base sample, denoted as PUS-1 (CMC1.00:CSN0.00).

Study on Rheological Properties of Waste Cooking Oil and Organic Montmorillonite Composite Recycled Asphalt

Pre-treated waste cooking oil (WCO) and organic montmorillonite (OMMT) were employed for the recycling of aged asphalt, which resulted in the improvement of the design of WCO asphalt rejuvenators and the enhancement of high-temperature performance of WCO-recycled asphalt. The effect of the rejuvenator and the properties of recycled asphalt were evaluated by viscosity, dynamic shear rheometer (DSR), bending beam rheometer (BBR) and scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and gel permeation chromatography (GPC) tests. The results indicated that aged asphalt could be obviously softened and restored to the level of original asphalt by adding 6% WCO. However, the high-temperature properties of recycled asphalt would be declined by adding too large a dose of WCO rejuvenator. The high-temperature performance of recycled asphalt was significantly improved by the WCO-OMMT complex rejuvenator, and the viscosity and rutting factor of recycled asphalt were increased. Light components of aged asphalt could be supplemented by WCO of the complex rejuvenator. The volatilization of small molecules could be slowed down by the peel structure formed by OMMT and small molecules of the asphalt, which resulted in the proportion of small molecular substances (SMS) being increased by 4% and improvement of the colloidal structure of aged asphalt. The high-temperature and low-temperature performance of recycled asphalt can be improved concurrently by the combination of 6% WCO and 1% OMMT, and this was evidenced by the fact that the high-temperature and low-temperature PG were all upgraded by one level.

Innovative strategies for time-release PCE design and cement paste flowability control

Extending the retention time of cement paste flowability with the addition of admixtures containing slow-release components is standard practice for ensuring the continued building quality of cement-based materials. This study aims to control the release rate of PCE and enhance its time-varying dispersion effect in fresh cement paste by utilizing Time-dependent Release PCEs (TRPCEs) with varying side-chain structures. The structural characterization of the synthesized TRPCEs was investigated using GPC (Gel Permeation Chromatography), FTIR (Fourier Transform Infrared Spectroscopy), and 1H NMR (Proton Nuclear Magnetic Resonance) techniques. Furthermore, experiments were carried out on time-varying flowability with different dosages of TRPCEs to investigate the flowability changes under the time-varying release effect. The influence of TRPCEs on cement hydration was examined using isothermal calorimetry by measuring the early hydration heat of cement paste. The time-dependent adsorption behaviors of TRPCEs were also examined using a TOC (Total Organic Carbon) analyzer. The findings show that TRPCEs have a minor effect on the cement hydration process's rapid reaction period but little effect on its induction and acceleration periods because of variations in the initial dispersion effect. Additionally, the adsorption behaviors of TRPCEs on cement particles vary significantly due to the hydrolysis of slow-release groups. The varying adsorption and consumption of TRPCEs on cement particles and hydration products in different hydration phases are key controlling factors for the time-varying flowability changes in cement paste. Finally, this innovative approach offers a novel perspective for designing and preparing new types of PCEs with a strong capability for time-varying flowability retention.

Thermal Reactivity of Bio-Oil Produced from Catalytic Fast Pyrolysis of Biomass.

Catalytic fast pyrolysis (CFP) of biomass is a versatile thermochemical process for producing a biogenic oil that can be further upgraded to sustainable transportation fuels, chemicals, and materials. CFP oil exhibits reduced oxygen content and improved thermal stability compared to noncatalytic fast pyrolysis oil. However, some level of reactive oxygenates remain in CFP oils, and reactions between these species can result in molecular weight growth and increased viscosity, leading to the potential for challenges during transportation, storage, and downstream processing. Previous research has provided considerable insight into the reactivity of noncatalytic fast pyrolysis oils, but CFP oils have yet to be studied in a similar fashion. Consequently, the degree of catalytic upgrading that is necessary to effectively stabilize CFP oils has yet to be established, and little is known about the mechanistic details underlying the process. The current study addresses this knowledge gap by controlling the CFP reaction conditions to systematically vary the oxygen content of the resulting oil. Accelerated thermal reactivity studies were then performed, and the CFP oils were analyzed using gas chromatography-mass spectrometry (GC-MS), Fourier transform ion cyclotron mass spectrometry (FT-ICR MS), gel permeation chromatography (GPC), and viscometry to evaluate the impact of heating on their physical and chemical properties. The results revealed that short chain carbonyls, anhydrosugars, and lignin derivatives with conjugated vinyl groups likely play a role in the thermal reactivity of CFP oils. Additionally, experiments performed across a wide variety of feedstocks revealed relatively low thermal reactivity for CFP oils with oxygen contents of <20 wt %. However, above this threshold value, the thermal reactivity grew exponentially as a function of oxygen content, resulting in large increases in viscosity and molecular weight. These results serve to deepen the mechanistic understanding of CFP oil thermal reactivity and help inform the development of quality specifications for catalytic upgrading to effectively stabilize CFP oils.

Synthesis of grafted copolymers of cod collagen and acrylamides in the presence of alkylborane – p-quinone system

The graft polymerization of acrylamide and N-isopropylacrylamide onto collagen in the presence of triethylborohexamethylenediamine complex and a number of p-quinones, including benzoquinone, naphthoquinone, 2,5-di-tretbutyl-p-benzoquinone, and duroquinone, was studied. In all cases, p-quinones act as polymerization retarders, reducing monomer conversion. An exception is the graft polymerization of acrylamide onto collagen in the presence of benzoquinone, which acts as a polymerization inhibitor. The proportion of the synthetic fragment in the obtained copolymers is determined by the structure of the monomer and p-quinone. The molecular weight distribution curves contain modes related to unreacted collagen, which differ significantly from those of the initial collagen in terms of intensity. This is related to the formation of a grafted copolymer of cross-linked structure, which cannot be analyzed by gel permeation chromatography. The degradation of copolymers under the action of enzymes was controlled by gel permeation chromatography. Enzymatic hydrolysis of copolymers proceeds slower than that of collagen, which confirms the formation of a copolymer. Following three hours after the onset of hydrolysis, the molecular weight distribution curves contain low-molecular weight modes of collagen and low-intensity modes related to polyacrylamide. The morphology of copolymers differs from that of collagen and polyacrylamides. Cytotoxicity evaluation of copolymers is an important research stage, determining their prospects as the basis of materials for regenerative medicine. An analysis of extracts obtained from the copolymers using culture medium by MTT assay showed a high rank of their toxicity, which can be reduced by dilution of collagen and N-isopropylacrylamide copolymer extracts with aqueous solutions. For the copolymers of collagen and acrylamide, the toxicity is maintained due to the high toxicity of the monomer. Their toxicity can be reduced by extraction of unreacted acrylamide with chloroform.

Synthesis of Amphiphilic Polyacrylates as Peelable Coatings for Optical Surface Cleaning

Optical instruments require extremely high precision, and even minor surface contamination can severely impact their performance. Peelable coatings offer an effective and non-damaging method for removing contaminants from optical surfaces. In this study, an amphiphilic polyacrylate copolymer (PMLEA) was synthesized via solution radical copolymerization using the lipophilic monomer lauryl acrylate (LA) and hydrophilic monomers ER-10, methyl methacrylate (MMA), and butyl acrylate (BA). The structure and molecular weight of the copolymer were characterized using Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and gel permeation chromatography (GPC). The hydrophilic–lipophilic balance, surface tension, and wettability of the copolymer were analyzed through water titration, the platinum plate method, and liquid contact angle tests. The cleaning performance of the copolymer coating on quartz glass surface contaminants was evaluated using optical microscopy and Ultraviolet-Visible Near-Infrared (UV-Vis-NIR) spectroscopy. The study examined the effect of varying the ratio of LA to ER-10 on the hydrophilicity, lipophilicity, cleaning efficiency, and mechanical properties of the copolymer coating. The results showed that when the mass ratio of LA to ER-10 was 1:2, the synthesized copolymer exhibited optimal performance in removing dust, grease, and fingerprints from quartz glass surfaces. The coating had a tensile strength of 2.57 MPa, an elongation at break of 183%, and a peeling force of 2.07 N m−1.