Gel Permeation Chromatography Analysis Research Articles

Transcriptomic profile of human erythroleukemia cells in response to Sargassum fusiforme polysaccharide and its structure analysis.

Sargassum fusiforme (S. fusiforme) has been used as an ingredient in Chinese herbal medicine for thousands of years. However, there are a limited number of studies concerning its therapeutic mechanism. High performance gel permeation chromatography (HPGPC) analysis showed that the average molecular weight of the S. fusiforme polysaccharide, SFPS 191212, is 43 kDa. SFPS 191212 is composed of mannose, rhamnose, galactose, xylose, glucose, and fucose (at a molar ratio: 2.1 : 2.9 : 1.8 : 15.5 : 4.6 : 62.5) with α- and β-configurations. The present research evaluated the anti-tumor potential of the S. fusiforme polysaccharide in human erythroleukemia (HEL) cells in vitro. To explore the SFPS 191212's apoptosis mechanism in HEL cells, transcriptome analysis was performed on HEL cells that were incubated with SFPS 191212. The inhibitory effect of SFPS 191212 on HEL cell growth was also analyzed. It was found that SFPS 191212 inhibited HEL cell proliferation, reduced cell viability in a concentration-dependent manner, and induced an insignificant toxic effect on normal human embryonic lung (MRC-5) cells. Compared with the control group, transcriptome analysis identified a total of 598 differentially expressed genes (DEGs), including 243 up-regulated genes and 355 down-regulated genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed on all DEGs, and 900 GO terms and 52 pathways were found to be significantly enriched. Finally, 23 DEGs were randomly selected and confirmed by quantitative real-time polymerase chain reaction (qRT-PCR). Moreover, SFPS 191212 down-regulated the PI3K/Akt signal transduction pathway. Our results provide a framework for understanding the effect of SFPS 191212 on cancer cells and can serve as a resource for delineating the anti-tumor mechanisms of S. fusiforme.

Synthesis and demulsification performance of a hyperbranched polymer with melamine as central core

A hyperbranched polymer (PMEL) was prepared using melamine as central core by a modified “one pot” method. The polymer was characterized by nuclear magnetic resonance spectroscopy (1H NMR and 13C NMR), Fourier transform infrared microscopy (FTIR), Gel permeation chromatography (GPC) and thermogravimetric analysis (TGA). Effect of standing time, temperature and concentration of PMEL on the demulsification performance of a diesel-in-water emulsion was investigated in detail. The transmittance of aqueous phase reached 91.3% if 50 mg/L of PMEL was added into an O/W emulsion for 240 min at ambient temperature. The interfacial tensions (IFT), zeta potential and microscopic analysis were further measured to explore the possible demulsifying mechanism. The current work shows that PMEL has a great application prospect in the demulsification of oil-water emulsion.

Heterologous production of hyaluronic acid in Nicotiana tabacum hairy roots expressing a human hyaluronan synthase 2

Hyaluronic acid (HA), a unique polysaccharide with excellent Physico-chemical properties, is broadly used in pharmaceutical, biomedical, and cosmetic fields. It is widely present in all vertebrates, certain bacterial strains, and even viruses while it is not found in plants, fungi, and insects. HA is naturally synthesized by a class of integral membrane proteins called Hyaluronic acid synthase (HAS). Thus far, industrial production of HA is carried out based on either extraction from animal sources or large-scale microbial fermentation. The major drawbacks to using these systems are contamination with pathogens and microbial toxins. Recently, the production of HA through recombinant systems has received considerable attention. Plants are eco-friendly ideal expression systems for biopharmaceuticals production. In this study, the optimized human hyaluronic acid synthase2 (hHAS2) sequence was transformed into Nicotiana tabacum using Agrobacterium rhizogenes. The highest rhHAS2 concentration of 65.72 ng/kg (wet weight) in transgenic tobacco hairy roots was measured by the human HAS2 ELISA kit. The HA production in the transgenic hairy roots was verified by scanning electron microscope (SEM) and quantified by the HA ELISA kit. The DPPH radical scavenging activity of HA with the highest concentration of 0.56 g/kg (wet weight) showed a maximum activity of 46%. Gel Permeation Chromatography (GPC) analyses revealed the high molecular weight HA (HMW-HA) with about > 0.8 MDa.

Antioxidant Additives Produced from Argan Shell Lignin Depolymerization

The present work summarizes the results of an experimental study focused on producing antioxidant additives for biofuels from argan shell lignin. The generation of this waste has noticeably increased in specific regions of Morocco as a result of the upward trend in the production of argan oil. Lignin extracted from argan shells via a semi-chemical pulping process was depolymerized under hydrothermal conditions in a stirred autoclave reactor at a temperature range of 250–350 °C. Lignin conversion to phenolic compounds was conducted in subcritical water together with different reaction medium (H2, CO2, and HCOOH). The organic fraction in the aqueous liquid product was extracted and blended with biodiesel at a dosage of 1 wt % to evaluate its antioxidant potential. According to the obtained results, the biodiesel oxidation stability time was drastically improved up to 400%. The depolymerization temperature was observed as a critical factor in the antioxidant potential of the additives, showing a maximum value at 300 °C, regardless of the reaction medium. An extensive characterization of the produced additives was performed. The phenolic monomers present in the produced additives were identified using gas chromatography–mass spectrometry, finding a notable presence of catechol, especially in the additives obtained at 300 °C, which led to the best results of biodiesel oxidation stability. Gel permeation chromatography analyses of the additives also showed a well dissolution of relatively big molecules (up to 7000 Da) in biodiesel. More efforts are required to verify the actual antioxidant potential of these types of molecules.

Wool Keratin Hydrolysates for Bioactive Additives Preparation.

The aim of this paper was to select keratin hydrolysate with bioactive properties by using the enzymatic hydrolysis of wool. Different proteolytic enzymes such as Protamex, Esperase, and Valkerase were used to break keratin molecules in light of bioactive additive preparation. The enzymatic keratin hydrolysates were assessed in terms of the physico-chemical characteristics related to the content of dry substance, total nitrogen, keratin, ash, cysteic sulphur, and cysteine. The influence of enzymatic hydrolysis on molecular weight and amino acid composition was determined by gel permeation chromatography (GPC) and gas chromatography-mass spectrometry (GC-MS) analyses. Antimicrobial activity of keratin hydrolysates was analysed against Fusarium spp., a pathogenic fungus that can decrease the quality of plants. The bioactivity of enzymatic hydrolysates was tested on maize plants and allowed us to select the keratin hydrolysates processed with the Esperase and Valkerase enzymes. The ratio of organised structures of hydrolysate peptides was analysed by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) deconvolution of the amide I band and may explain the difference in their bioactive behaviour. The most important modifications in the ATR spectra of maize leaves in correlation with the experimentally proven performance on maize development by plant length and chlorophyll index quantification were detailed. The potential of enzymatic hydrolysis to design additives with different bioactivity was shown in the case of plant growth stimulation.

How Poloxamer Addition in Hyaluronic-Acid-Decorated Biodegradable Microparticles Affects Polymer Degradation and Protein Release Kinetics

Polymeric microparticles (MPs) designed for the intravitreal administration of therapeutic proteins result in a prolonged half-life in the vitreous and can delay or discourage the onset of adverse effects inevitably related to this route of administration. Hence, here we designed MPs composed of a polymeric blend based on poly(lactic-co-glycolic) acid and poloxamers, externally decorated with hyaluronic acid. The MPs are intended for intravitreal administration of bovine serum albumin. In detail, a systematic formulative study aiming to shed light on the complex relationship between protein release rate and MP degradation rate was carried out by means of calorimetric and gel permeation chromatography analyses. We found out that poloxamer addition caused a compact MP matrix, which led to a slight modification of the degradation kinetics and a reduction in the initial BSA initial release, which is of the utmost importance to ensure a relatively regular BSA release. It must also be underlined that for acid-labile molecules such as proteins, the poloxamer’s presence induced complex and hardly predictable effects on MP degradation/protein release, due to the dynamic balance between the time-evolving hydrophilicity of MPs and the influence of poloxamers themselves on the PLGA degradation rate.

Preparations of Poly(lactic acid) Dispersions in Water for Coating Applications.

A green, effective methodology for the preparation of water-based dispersions of poly(lactic acid) (PLA) for coating purposes is herein presented. The procedure consists of two steps: in the first one, an oil-in-water emulsion is obtained by mixing a solution of PLA in ethyl acetate with a water phase containing surfactant and stabilizer. Different homogenization methods as well as oil/water phase ratio, surfactant and stabilizer combinations were screened. In the second step, the quantitative evaporation of the organic provides water dispersions of PLA that are stable, at least, over several weeks at room temperature or at 4 °C. Particle size was in the 200–500 nm range, depending on the preparation conditions, as confirmed by scanning electron microscope (SEM) analysis. PLA was found not to suffer significant molecular weight degradation by gel permeation chromatography (GPC) analysis. Furthermore, two selected formulations with glass transition temperature (Tg) of 51 °C and 34 °C were tested for the preparation of PLA films by drying in PTFE capsules. In both cases, continuous films that are homogeneous by Fourier-transform infrared spectroscopy (FT-IR) and SEM observation were obtained only when drying was performed above 60 °C. The formulation with lower Tg results in films which are more flexible and transparent.

Potential Eco‐Friendly Multifunctional Lube Oil Additives: Synthesis, Characterization and Performance Evaluation

AbstractHomo polymer of dodecyl acrylate (DDA) and its copolymers with citral at different percentage composition (w/w) were synthesized by free radical polymerization method. The characterization of all the polymers was carried out through FTIR, NMR and GPC (gel permeation chromatography) analysis. The performance of all the prepared polymers as viscosity index improver (VII), pour point depressant (PPD) and antiwear (AW) additive in two different base oils (BO1 and BO2) were evaluated by standard ASTM methods. The results showed that all the polymers are good as VII, AW and PPD additives. AW and PPD properties of copolymers are better compared to homopolymer. Out of the three additive properties, PPD properties of copolymer (P‐2) was remarkably improved upto −26 °C for at 1 % (w/w) in base oil compared to homopolymer of dodecyl acrylate (−18 °C at 1 % w/w) as confirmed by photo micrographic analysis. The thermal stability of the polymers was determined by thermo gravimetric analysis (TGA). The stability against thermal degradation increases with increasing citral content in the acrylate backbone. Moreover the copolymers were eco‐friendly which was confirmed by biodegradability test (Disc Diffusion and Soil Burial Test method).

Extraction and Analysis of Natural Rubber from the Latex of Ficus carica, Artocarpus heterophyllus and Polymer Analysis of Durio zibethinus

In tropical fruits such as durian (Durio zibethinus) and jackfruit (Artocarpus heterophyllus), only one quarter to one third of the fruit is edible. Finding more ways to industrially use the other components of the fruit can reduce the waste burned or dumped in landfills. Another fruit tree of interest that can also grow in Austria is the fig tree (Ficus carica). Currently, the fruits are the main product of that plant; however, components in the latex of the tree are of interest too. The latex is known to contain natural rubber, which could potentially be used for industrial applications. Jackfruit trees also produce latex, which contains natural rubber. In both cases, the natural rubber has different properties compared to the conventionally used rubber from the rubber tree (Hevea brasiliensis). This could provide new opportunities in various applications. Therefore, the purpose of this research is to analyze the properties of the natural rubber obtained from the jackfruit and fig trees. Additionally, durian fruit also produces a sticky liquid, so the same experiments were also carried out with durian samples. The experimental procedure included extraction with acetone and cyclohexane as well as polymer length determination with gel permeation chromatography and polymer analysis with differential scanning calorimetry. The results show that in both jackfruit and fig tree latex, there is natural rubber of similar polymer length. Durian pulp also contains a polymer; however, with these experiments, it could not be identified. Further research is required to identify the durian polymer and to confirm the results of this experiment.

Effect of Sulfonated Block Copolymer on the Equilibrium and Thermal Properties of Sulfonated Fluoroblock Copolymer Blend Membranes

Polymeric membrane technologies demand the synthesis of new polymers to enhance their equilibrium, thermal, and transport properties. Therefore, the focus of this investigation was the evaluation of the equilibrium and thermal properties of a sulfonated fluoroblock copolymer blend membrane composed of sulfonated poly(styrene-isobutylene-styrene) (SIBS SO3H) and a novel sulfonated fluoroblock copolymer composed of poly(4-fluo- rostyrene) (P4FS), poly(styrene) (PS) and poly(isobutylene) (PIB). The fluoroblock copolymer was synthesized using Atom Transfer Radical Polymerization (ATRP) and cationic polymerization. First, the molecular weight and the thermal stability of the block copolymer were determined using Gel Permeation Chromatography (GPC) and Thermogravimetric Analysis (TGA). Second, the chemical composition was monitored utilizing Fourier Transform Infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. The molecular weight of P4FS-b-PS was Mn ~ 36,100; this value increased 8% after the cationic polymerization. The equilibrium properties of the membrane were evaluated using the water uptake and Ion-Exchange Capacity. The degradation behavior and the thermal transitions were determined using TGA and Differential Scanning Calorimetry (DSC), respectively. This newly membrane exhibited water uptake higher than 608% related to the improvement of 36% in the ion-exchange capacity and the increment of 25.31% and 25.24% in the energy required to produce the thermal transitions induced by the addition of the sulfonated fluoroblock copolymer.

Novel polysaccharide extracted from Sipunculus nudus inhibits HepG2 tumour growth in vivo by enhancing immune function and inducing tumour cell apoptosis.

A novel polysaccharide was extracted from Sipunculus nudus (SNP). The molecular weight (MW) of SNP was determined to be 9223 Da by high‐performance gel permeation chromatography analyses, and the structure of the SNP repeat units was determined to be →3,4‐β‐D‐GlcpNAC (1→ and →4) ‐α‐D‐Glcp (1→ in the ratio of 15:1; →2) ‐α ‐D‐Galp ‐ (1→ as a side chain; and β‐D‐Galp‐(1→ and α‐ D‐Glcp ‐ (1→ as end groups by GC‐MS analysis and NMR assays. The effect of SNP on hepatoma HepG2‐bearing mice was analysed to verify its potential in the clinical treatment of liver cancer. A total of 90 male athymic nu/nu mice were divided into therapeutic and preventive groups and fed with different amounts of SNP. The antitumour effect of SNP on HepG2‐bearing mice and mechanism of such were studied by analysing the tumour size, spleen index, thymus index, immune factors in the blood, tumour apoptosis factors, etc. The results suggest that SNP not only increased the index of immune organs in the body, but also enhanced the secretion of immune factors, including interleukin‐2, interferon gamma and tumour necrosis factor‐alpha in the serum. SNP induced the apoptosis of tumour cells via the mitochondrial apoptosis pathway, which upregulated caspase‐3, caspase‐8, caspase‐9 and BCL2‐associated X, but downregulated B‐cell lymphoma‐2 and vascular endothelial growth factor protein expression. In conclusion, SNP inhibited tumour growth by enhancing immune function and inducing tumour cell apoptosis in HepG2‐bearing mice. Therefore, SNP may be further investigated as a promising candidate for future antitumour drugs.

Polymerization of Allenes by Using an Iron(II) β-Diketiminate Pre-Catalyst to Generate High Mn Polymers.

Herein, we report an iron(II)‐catalyzed polymerization of arylallenes. This reaction proceeds rapidly at room temperature in the presence of a hydride co‐catalyst to generate polymers of weight up to M n=189 000 Da. We have determined the polymer structure and chain length for a range of monomers through a combination of NMR, differential scanning calorimetry (DSC) and gel permeation chromatography (GPC) analysis. Mechanistically, we postulate that the co‐catalyst does not react to form an iron(II) hydride in situ, but instead the chain growth is proceeding via a reactive Fe(III) species. We have also performed kinetic and isotopic experiments to further our understanding. The formation of a highly unusual 1,3‐substituted cyclobutane side‐product is also investigated.

Submerged cultivation, characterization and in vitro antitumor activity of polysaccharides from Schizophyllum radiatum

Production of polysaccharides by white-rot-fungi in submerged cultivation has several advantages due to process control. This work deals with the submerged cultivation, extraction and antitumor activity of polysaccharides from a wild strain of Schizophyllum radiatum isolated from a tropical forest of Colombia. The mushroom was cultivated in laboratory conditions, and classified by classical and molecular taxonomy. Submerged cultivation was performed in a bioreactor of 5 L using a ligninolytic residue as substrate. The fermentation conditions were 30 ± 1 °C, pH 4.5, 300 rpm and 1.5 vvm of air for 4 days. The yields were 16.8 g/L (w/v) of biomass, and after extraction, 0.6 g/L of water-soluble exopolysaccharide (SEPS) and 2.01 % (w/w) of water-soluble intrapolysaccharide (SIPS) were obtained. In each extract total carbohydrate, glucans and protein contents were determined. Also, nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffractometry (XRD), high performance liquid chromatography with refraction index detection (HPLC-RI), high performance gel permeation chromatography (HPGPC) and Nuclear Magnetic Resonance (NMR) analysis were performed. Results indicated that SEPS and SIPS are heteropolysaccharides with amorphous structure and high molecular weights. Antitumor and immunostimulant activity was evaluated in different cancer cell lines. The results suggest these polysaccharides have direct and indirect antitumor activity activating immune cells such as macrophages. These findings enhance our knowledge about new sources of fungal metabolites that serve as adjuvant, cheaper and less harmful alternatives to cancer treatment.

Chemo-Rheological Characterization of the Effect of Iran Rock Asphalt on the Performance of Waste Bio-Oil Modified Asphalts

This study aims to investigate the effect of Iran rock asphalt (IRA) on the rheological performance of waste bio-oil modified asphalt (WBMA). Three kinds of WBMA with bio-oil origins including soybean oil residue, castor oil residue, and waste cooking oil residue were blended with different dosages of IRA. The high-temperature performance of the three blended asphalt binders was evaluated using the temperature sweep test and multiple stress creep recovery (MSCR) test. The effect of IRA on the fatigue performance and low-temperature cracking resistance of the three WBMAs was evaluated using the linear amplitude sweep (LAS) test and the bending beam rheometer (BBR) test. A gel permeation chromatography (GPC) test was conducted to further understand the contribution of IRA to the overall rheological performance of different WBMAs. Results indicated that the high-temperature performance of the three WBMAs was enhanced significantly with the increase of IRA content. The predicted fatigue life from the LAS test showed that the incorporation of IRA extended the fatigue life of the three WBMAs at a lower strain level, while this effect was not profound at a higher strain level. Results from BBR test showed that IRA may increase the risk of low-temperature cracking and that the dosage of IRA should be limited to fulfill the requirements of the low-temperature performance. The GPC analysis revealed that the enhanced high-temperature performance and reduced low-temperature cracking resistance of WBMAs modified with IRA was mainly a result of the increased asphaltene concentration.

Pruning Influence on Chemical Composition of Spruce Wood (Picea abies (L.) Karst.)

The aim of the work was to investigate the influence of pruning on wood composition in different morphological parts of the Norway spruce (Picea abies (L.) Karst.) trees, including heartwood and sapwood compared to normal trees as a reference. Pruning intensity during that treatment was 35–41 % of the total length of the crown for the trees with the average and less than average diameter at breast height and 28 % for the trees with diameter at breast height higher than the average. Components composition of acetone soluble extractives was analysed by gas chromatography with long and short columns, and their molar mass distribution was analysed by gel permeation chromatography. The following was determined in the pre-extracted wood tissues: cellulose (acid hydrolysis – gas chromatography); lignin (Acetyl Bromide method) and hemicellulose and pectins composition (acid methanolysis – gas chromatography). Acetone-soluble wood extractives are a complex mixture of different groups of organic compounds, i.e. both lipophilic and polar substances. The high-performance gel permeation chromatography analysis revealed the dominance of triglycerides, steryl esters, fatty and resin acids in the obtained extracts. The amount of monosaccharides in the extracts was also substantial. The chemical composition of wood tissues of the reference and pruned trees was almost similar. Compared to the reference trees, the wood samples of the pruned trees showed increased amounts of resin acids in sapwood, high amounts of lignin and double amounts of fructose in both sapwood and heartwood. The analysis results can be explained by response of trees to their pruning as a defense mechanism against plant pathogens and must be a result of the current physiological activity of those trees, possibly related to differences in crown sizes.For citation: Pranovich A.V., Antonov O.I., Dobrovolsky A.A. Pruning Influence on Chemical Composition of Spruce Wood (Picea abies (L.) Karst.). Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 3, pp. 145–160. DOI: 10.37482/0536-1036-2021-3-145-160

Isolating High Antimicrobial Ability Lignin From Bamboo Kraft Lignin by Organosolv Fractionation.

Lignin from different biomasses possess biological antioxidation and antimicrobial activities, which depend on the number of functional groups and the molecular weight of lignin. In this work, organosolv fractionation was carried out to prepare the lignin fraction with a suitable structure to tailor excellent biological activities. Gel permeation chromatography (GPC) analysis showed that decreased molecular weight lignin fractions were obtained by sequentially organosolv fractionation with anhydrous acetone, 50% acetone and 37.5% hexanes. Nuclear magnetic resonance (NMR) results indicated that the lignin fractions with lower molecular weight had fewer substructures and a higher phenolic hydroxyl content, which was positively correlated with their antioxidation ability. Both of the original lignin and fractionated lignins possessed the ability to inhibit the growth of Gram-negative bacteria (Escherichia coli and Salmonella) and Gram-positive bacteria (Streptococcus and Staphylococcus aureus) by destroying the cell wall of bacteria in vitro, in which the lignin fraction with the lowest molecular weight and highest phenolic hydroxyl content (L3) showed the best performance. Besides, the L3 lignin showed the ability to ameliorate Escherichia coli-induced diarrhea damages of mice to improve the formation of intestinal contents in vivo. These results imply that a lignin fraction with a tailored structure from bamboo lignin can be used as a novel antimicrobial agent in the biomedical field.

One-Pot Synthesis of Supertough, Sustainable Polyester Thermoplastic Elastomers Using Block-Like, Gradient Copolymer as Soft Midblock

It remains challenging to synthesize supertough thermoplastic elastomers (TPEs) since the stretchability and tensile strength are mutually exclusive. Here, we report a one-pot strategy for the prep...

Synthesis of CO2‐based functional poly(carbonate‐co‐lactide)

AbstractTPPAlCl‐PPN+Cl− binary catalyst (where TPPAlCl is 5,10,15,20‐tetraphenylporphyrin aluminum chloride, PPN+Cl− is bis[triphenylphosphine] iminium chloride, the molar ratio of TPPAlCl to PPN+Cl− is 1 to 0.5) can initiate the effective one‐pot/one‐step ternary copolymerization of CO2, lactide and 4‐vinyl‐1‐cyclohexene‐1,2‐epoxide, and the quaternary copolymerization of CO2, propylene oxide, lactide, 4‐vinyl‐1‐cyclohexene‐1,2‐epoxide, to form multiblock poly(carbonate‐co‐lactide) products with pendant vinyl group. The ternary copolymerization product composes of polylactide (PLA) block and poy(vinylcyclohexylene carbonate) (PVCHC) block, and the quaternary copolymerization product composes of poy(propylene carbonate) (PPC) block, PLA block and PVCHC block, which are verified by 1H NMR, 13C NMR, 1H‐1H cosy, hetero‐nuclear multiple bond correlation, DTG, and Gel permeation chromatography analysis. The functionality and glass‐transition temperature of the products can be easily adjusted by the copolymerization variables, such as the molar ratio of comonomers, copolymerization temperature, pressure of CO2, the concentration of the catalyst.

Biodegradation of waste asphalt shingle by white rot fungi

Waste asphalt shingle (WAS) has traditionally been disposed of by landfilling due to environmental concerns surrounding Polycyclic aromatic hydrocarbons in WAS, which may potentially leach out, causing environmental pollution. However, this disposal method has been less environmentally acceptable and less cost effective than in the past due to concern on land resources. This study evaluates the potential of degradation of WAS, therefore reducing the polycyclic aromatic hydrocarbons (PAHs) content, by exploiting microbial biodegradation. The white rot fungus Phanerochaete chrysosporium was tested for its potential to degrade waste asphalt shingle binder. The biodegradation process was analyzed and quantified by both Fourier-transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). Results illustrate that P. chrysosporium can degrade WAS binder. GPC analysis indicates that the small asphaltic molecules were biodegraded preferentially by P. chrysosporium. The PAHs content of the WAS binder increased initially during fungal biodegradation, but subsequently decreased with the progression in biodegradation to a level lower than that of the original shingle binder. Results from this study could be used to develop solutions to the sustainable management of waste asphalt shingles.

Production of Cyclic Anhydride-Modified Starches

Modified starches offer a biodegradable, readily available, and cost-effective alternative to petroleum-based products. The reaction of alkenylsuccinic anhydrides (ASAs), in particular, is an efficient method to produce amphiphilic starches with numerous applications in different areas. While ASAs are typically derived from petroleum sources, maleated soybean oil can also be used in an effort to produce materials from renewable sources. The reaction of gelatinized waxy maize starch with octenylsuccinic anhydride (OSA), dodecenylsuccinic anhydride (DDSA), a maleated fatty acid (TENAX 2010), phthalic anhydride (PA), 1,2,4-benzenetricarboxylic acid anhydride (trimellitic anhydride, TMA), and three maleated soybean oil samples, was investigated under different conditions. To minimize the reaction time and the amount of water required, the outcome of the esterification reaction was compared for starch dispersions in benchtop dispersed reactions, for starch melts in a heated torque rheometer, and for reactive extrusion in a pilot plant scale twin-screw extruder. The extent of reaction was quantified by 1H NMR analysis, and changes in molecular weight and diameter were monitored by gel permeation chromatography (GPC) analysis. The outcome of the reactions varied markedly in terms of reaction efficiency (RE), molecular weight distribution, and average hydrodynamic diameter, for the products derived from the different maleated reagents used, as well as for the different reaction protocols.