The non-biodegradability of traditional plastics poses serious environmental challenges, while the high cost of biodegradable plastics limits their widespread application. Starch, due to its abundance, low cost, and biodegradability, represents a promising alternative. However, the strong intermolecular hydrogen bonding within starch impedes its processing. To address this limitation, a novel plasticizer, 6-hydroxy-N-[2-[(2-hydroxyethyl)amino]ethyl]hexanamide (HEEHA), was synthesized to enhance the thermoplasticity of starch. Thermoplastic starch (TPS) films were fabricated by blending HEEHA with glycerol at varying ratios, maintaining a total plasticizer content of 30 wt% relative to dry starch. Their properties were characterized using FT-IR, XRD, and mechanical testing, while molecular dynamics simulations were conducted to analyze mean square displacement (MSD), radial distribution function (RDF), and hydrogen bond energy, providing insights into the underlying plasticization mechanisms. The combination of HEEHA and glycerol exhibited synergistic effects, achieving optimal performance at a 10 wt% HEEHA/20 wt% glycerol ratio, where both tensile strength and elongation at break surpassed those of single-plasticizer systems. Simulations further revealed that, at this ratio, the plasticizers displayed the highest diffusion coefficients, the most uniform spatial distribution, and the strongest hydrogen bonding interactions. The resulting TPS retained moderate starch crystallinity, contributing to enhanced mechanical properties.

Straw, biochar, dimethylpyrazole phosphate (DMPP), and polyaspartic acid (PASP) are promising materials to improve soil productivity and alleviate agricultural pollution. However, the comparison of these four materials in rice cultivation, in terms of fertilizer use efficiency and crop yield enhancement, remains limited. A pot experiment was therefore conducted to elucidate the comparative impacts of these materials on gaseous nitrogen loss, rice growth, nutrient uptake, soil properties, and soil nitrifying bacteria during different growth stages with the aim of identifying the optimal material facilitating rice production. Six treatments were designed as follows: no nitrogen fertilizer (PK), conventional fertilization (NPK), partial substitution of nitrogen in NPK with straw (NPKS), partial substitution of nitrogen in NPK with biochar (NPKC), NPK plus DMPP application (NPKD), and NPK plus PASP application (NPKP). For the whole growth period, the inhibition of NH3 volatilization only occurred in NPKP (17.22

The employment of scale inhibitors is one of the most cost-effective and efficient solutions for circulating cooling water systems that are prone to scaling. The synthesis and application of environmentally friendly scale inhibitors attract increasing interest with the enaction of more and more stringent environmental protection policies. In this study, the intermediate N, N'-ethylenebismaleamic acid (EBMAA) was synthesized from maleic anhydride (MAH) and ethylenediamine (EDA). Subsequently, the novel scale inhibitor polyethylenebismaleamic acid-ethylenediamine (PEBMAA-EDA) was synthesized by chain extension reaction of EBMAA and EDA. The structure of EBMAA and PEBMAA-EDA was confirmed by FT-IR and 1H NMR. The impact of reaction conditions on the yield of EBMAA and the viscosity characteristic of PEBMAA-EDA was examined in detail. The scale inhibition performance of PEBMAA-EDA was evaluated according to GB/T 16,632-2019 standard, and results revealed that the scale inhibiting ratio increased with the increase of intrinsic viscosity of PEBMAA-EDA. Compared with traditional polyaspartic acid (PASP), PEBMAA-EDA demonstrated superior scale inhibition performance, achieving a maximum inhibition rate of 83.61 % at a dosage of 20 mg & sdot;L- 1. Furthermore, the scale inhibition mechanism of PEBMAA-EDA was elucidated by the analysis of results of quantum mechanical computation, molecular dynamics simulation (MD), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Results indicated that PEBMAA-EDA exerts scale inhibition performance through mechanisms involving chelation, lattice distortion, adsorption and dispersion. This study offers a novel insight and methodology for developing phosphate-free scale inhibitors.

Plasticizers are essential in starch processing and performance enhancement. Literature reports suggest that amide plasticizers outperform polyols in starch plasticization. To explore the influence of amide plasticizer molecular size on starch plasticization, a novel plasticizer, N,N-bis(2-formamidoethyl)-formamide (BFEF), containing three amide groups, was synthesized. Molecular dynamics (MD) simulations were performed to construct three plasticizer/starch/water systems using formamide (FM), ethylenebisformamide (EBF), and BFEF as the plasticizers. The mean square displacement (MSD), radial distribution functions (RDF), and hydrogen bonding energies for each system were calculated to assess the effects of the number and structure of amide groups on starch plasticization. Additionally, thermoplastic starches (TPSs) were prepared with these plasticizers, and their properties were characterized by DMA, XRD, FT-IR, SEM, and mechanical testing. The results show that while an increase in the number of amide groups and molecular size impedes the diffusion of the plasticizer into the starch matrix and weakens the interaction between the plasticizer and starch, the preservation of starch crystallinity in the TPS improves its tensile strength. Specifically, the tensile strength of TPS prepared with BFEF (6.6 MPa) was significantly higher than that of TPS prepared with FM (3.75 MPa).

Scaling in circulating cooling water not only reduces production efficiency but can also cause severe equipment damage. Nowadays, the development of phosphorus-free, biodegradable scale inhibitors has become a significant research focus. In this study, aminoethylpiperazine (AEP) was employed as a modifier to functionalize polysuccinimide (PSI) via a ring-opening reaction to synthesize a novel and highly effective inhibitor named PASP-AEP. The structure of PASP-AEP was characterized using FT-IR and 1H NMR spectroscopy. Scale inhibition experiments demonstrated that PASP-AEP exhibits outstanding scale inhibition performance at a lower dosage. At concentrations as low as 1 mg & sdot;L-1 and 2 mg & sdot;L-1, it achieved 100 % inhibition rates against calcium sulfate and calcium carbonate scales, respectively, representing a significant (7-fold) dosage reduction compared to the conventional polyaspartic acid (PASP) for CaSO4 inhibition and a dramatic performance enhancement for CaCO3. SEM and XRD analyses revealed that PASP-AEP inhibits scale formation through mechanisms including adsorption and crystal modification effects. Molecular dynamics simulations further indicated that the increased number of hydroxyl groups and nitrogen atoms within the PASP-AEP molecular chain enhances its binding energy with Ca2+ by over 80 % compared to the conventional PASP. This significantly stronger interaction energy, corroborated by RDF analysis, facilitates its effective adsorption onto active crystal sites and is a key factor for its superior performance. The modification of PSI with AEP achieves synergistic effects through multiple scale inhibition mechanisms, primarily through effective surface adsorption and steric hindrance effects, providing an efficient and environmentally friendly scale inhibition solution for industrial water treatment with promising application potential.

Thermoplastic starch (TPS), derived from renewable and low-cost starch, represents a significant segment of biodegradable plastics. In this study, a novel plasticizer containing both amide and hydroxyl groups named N-(2-hydroxyethyl)-N,N'-ethylbis(formamide) (HEF) was designed, and the plasticizing effect of which was evaluated using molecular dynamics simulations (MD), with key metrics including the mean square displacement (MSD), radial distribution function (RDF), and hydrogen bonding energy. MD simulations suggest that HEF can form hydrogen bonds not only with the ether linkages in the starch main chain but also with the hydroxyl groups present on the starch molecules, thereby enhancing its plasticizing effect. To validate these findings, HEF was synthesized for the preparation of HEF-plasticized starch (HEFTPS), and glycerol-plasticized starch (GTPS) was also prepared for comparison. The results showed that HEF forms stronger hydrogen bonding interactions with starch than glycerol does, and HEFTPS exhibits higher tensile strength than GTPS, indicating that HEF provides a superior plasticizing effect for starch.

To investigate the impact of plasticizer functional groups on starch plasticization, three distinct plasticizers were selected in this study: ethylene glycol (EG), ethylenediamine (EDA), and ethylenebisformamide (EBF). Three models of the plasticizer/starch system were constructed using molecular dynamics (MD) simulations, and the analysis encompassed the computation of mean square displacement (MSD), radial distribution function (RDF), and hydrogen bonding energy for each system. Additionally, the proportions of simulation were used to prepare thermoplastic starch films, which were subsequently subjected to examinations such as DSC, XRD, FT-IR, SEM, and mechanical property testing. Comparative analysis of the simulation data from the three systems and the properties of the manufactured thermoplastic starch (TPS) established that the diverse functional groups of plasticizers significantly influenced starch plasticization. In different plasticizer functional group types, it was observed that hydroxyl groups in EG and amino groups in EDA predominantly form hydrogen bonds with hydroxyl groups in starch molecular chain. In contrast, amide groups in EBF can establish hydrogen bonds not only with hydroxyl groups of starch but also with ether bonds on the starch main chain, thereby resulting in more effective starch plasticization.

Modified polyaspartic acid (M-PASP) was synthesized by modifying ammonia- polysuccinimide (ammonia-PSI) through a ring-opening reaction using a modifier derived from ethylenediamine, maleic anhydride, and NaOH. In addition to M-PASP, conventional polyaspartic acid (PASP) was also synthesized for comparison. The structure of conventional PASP and M-PASP were characterized by FT-IR and 1H NMR. The influence of raw materials ratio, reaction temperature and reaction time on the intrinsic viscosity of M-PASP were investigated in detail. The static scale inhibition method was used to evaluate the scale inhibition performance. The results showed that M-PASP exhibited significantly superior scale inhibition performance against CaCO3 compared to conventional PASP. Additionally, it was observed that the scale inhibition rate of M-PASP on CaCO3 increased with increasing intrinsic viscosity. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were employed to examine the surface morphology and structure of CaCO3 crystals, respectively. The results revealed that the addition of M-PASP led to a reduction in the grain size of CaCO3 crystals and disruption of their surface morphology. In addition, molecular dynamics (MD) simulation was utilized to analyze the interaction mechanism between the polymers and calcium carbonate crystals. Based on the findings, it was postulated that the scale inhibition mechanism of M-PASP against CaCO3 involves a comprehensive interplay of several factors, including chelation solubilization, dispersion aggregation and lattice distortion.

To investigate the impact of water content on starch plasticization, the molecular dynamics (MD) simulation method was employed to investigate the hydrogen bonding energy, radial distribution function (RDF) and mean square displacement (MSD) of the starch/glycerol/water system at various water contents (ranging from 8% to 14%, based on the dry starch weight). Additionally, Glycerol-plasticized thermoplastic starches (GTPSs) were prepared using a twin-screw extruder with precise material proportions according to the simulation ratio. Subsequently, DSC, XRD, FT-IR, SEM and mechanical properties of GTPSs were evaluated. By conducting an analysis on the correlation between simulation results and TPS performance, it has been demonstrated that water molecules play a pivotal role in the plasticization process of starch. GTPS exhibits challenges in processing due to its inadequate melt fluidity at lower water content (≤11%). Conversely, excessive water content (≥13%) leads to a decline in the mechanical properties of GTPS. Considering both processing stability and material’s mechanical properties, a starch water content of 12% is deemed suitable for TPS preparation.

聚天门冬氨酸酯(PAE)聚脲涂料是由氨基酸酯和异氰酸酯制备的弹性材料,具有凝胶时间可控、固含量高、溶剂少、耐腐蚀、绿色环保等特点.因此,它已广泛应用于混凝土防护、防水防腐、胶黏剂、地坪涂料等众多领域,并具有广阔的发展前景.文中综述了PAE聚脲涂料的合成,并详细阐述了其合成原理、优缺点,重点介绍了不同组分和改性方法对产品性能的影响;综述了PAE聚脲涂料在不同领域的应用及应用实例.最后,对其进一步发展和应用进行了展望.

Background In the past decades, ever-increasing fertilizer use has led to a continuous increase in agricultural output. However, serious waste of resources occurs because of the low utilization of fertilizers. Polyaspartic acid (PASP) is a biodegradable polymer that can be used as a fertilizer synergist in agricultural production to improve the nutrient utilization capacity of plants. For polymers, the molecular weight (MW) often affects their effectiveness. However, little information is available on the effects of PASP MW in agriculture, especially on nitrogen leaching and plant element uptake. Results This work was conducted to identify the effect of PASPs with three different MWs - PASP-1 (MW: 5517), PASP-2 (MW: 6934), and PASP-3 (MW: 7568) - on nitrogen leaching, lettuce growth, and wheat cultivation. The results revealed that PASP favored plant growth and nitrogen accumulation in the soil, independent of crop species. PASP with a higher MW improved yields and the agronomic characteristics of lettuce and wheat. Furthermore, apparent amelioration of nitrogen use efficiency for lettuce (7.6%, 12.8%, and 15.0%) and wheat (4.6%, 8.1%, and 9.2%) was observed in the treatments with PASP addition. The effects and merits of PASPs on preventing ammonium nitrogen leaching and improving lettuce and wheat productivity were as follows: PASP-3 > PASP-2 > PASP-1. Conclusion The MW of PASP is an essential factor affecting inorganic nitrogen leaching and crop productivity, and PASP with a higher MW (7568) is recommended for application in agriculture. (c) 2022 Society of Chemical Industry.

In this work, oxidized starch with high carbonyl contents is obtained in a rather simple way using corn starch as raw material and NaBrO as an oxidizer. The produced oxidized starch is evaluated by measuring the carboxyl content, carbonyl content, yield, and the intrinsic viscosity. The influences of pH, reaction time, temperature and oxidizer content on carbonyl content, carboxyl content, intrinsic viscosity, and yield of the oxidized starch are investigated in detail. It is found that the reaction conditions are readily controlled, and the higher carbonyl contents as well as yield of oxidized starch can be obtained compared with those reported previously, leading to promising products. The formation of carboxyl and carbonyl groups on the oxidized starch is confirmed by FT‐IR. The changes of crystallinity and the apparent morphology of oxidized starch are characterized with XRD and SEM, respectively.

ABSTRACT Polyaspartic acid (PASP) is a low-cost, environmentally friendly, and multifunctional polymer material. The knowledge regarding the effects of PASPs, especially the PASPs with a different molecular weight (MW), on nitrogen use efficiency (NUE), ammonia (NH3) volatilization and nitrous oxide (N2O) emission in crop fields is scarce. In this study, maize pot experiments were conducted to evaluate three types of PASPs with different MW. Five treatments were designed: (1) application of chemical phosphorus (P) and potassium (K) fertilizer (PK), (2) PK plus urea (NPK), (3) NPK plus PASP-1 (PASPT1, MW: 5517), (4) NPK plus PASP-2 (PASPT2, MW: 6934), and (5) NPK plus PASP-3 (PASPT3, MW: 7568). The yield indicators of crop height, straw dry weight and 100-grain weight showed that PASP application improved the crop growth. In PASP3, NUE reached 46.1%, almost double of that in NPK (28.6%). Moreover, there were significantly less N losses in the forms of NH3 volatilization and NO2 emission following PASP amendment than regular urea application. Another positive impact revealed that PASP inhibited the transformation of NH4+-N to NO3–N. Among the three PASPs, PASP-3 with the highest MW overall presented optimal effects, implying that MW was a major driving factor for PASP performance on maize production.

Rapid hydrolysis of urea results in further fertilization frequency and excessive nitrogen (N) input. A modified urea, dimethylolurea (DMU), was synthesized in this study. The structure of the sample was characterized by Fourier transform infrared and nuclear magnetic resonance analysis, manifesting the formation of DMU. N release investigation confirmed that DMU enabling provided a gradual N supply. The N leaching experiment indicated that increasing the applied DMU significantly reduced the NH4+-N, NO3--N, and total N leaching, compared with urea application alone. The application effect on maize and wheat was evaluated. The results revealed that singly applied DMU with 100% or 80% N input, irrespective of the amount, promoted crop yield and agronomic characteristic and N use efficiency (NUE) of maize and wheat, beyond urea with two split applications at the recommended rate. Thus, the potential availability of DMU was proven; this could be widely used in agricultural fields as a slow-release fertilizer.

Polyaspartic acid/salt (PASP),a novel biodegradable and environmental-friendly material,has found wide applica-tion in many fields by virtue of its special molecular chain structure and excellent properties,and has attained notable improvement in technological diversification of synthesis &modification,product type &performance,and application range,due to the deep and in-tensive research endeavors in recent years.This review renders a vivid description upon the synthesis/modification techniques,the in-dustrial/agricultural applications (e.g.scale inhibitor,corrosion inhibitor,fertilizer synergist,water retention agent,and paint), biomedical and other applications.We also sketch out the prospective development tendency of PASP and the relevant derivatives.

The molecular dynamics (MD) simulation method was used to investigate the hydrogen bonding energy of starch/glycerol system under different temperatures (range from 90°C to 120°C) and different glycerol contents (range from 20% to 40%, based on dry starch weight). These effects on the hydrogen bonding energy (including the total hydrogen bonding energy, hydrogen bonding energy of starch/starch, glycerol/glycerol, and starch/glycerol) were analyzed in detail. Meanwhile, glycerol plasticized starch films were prepared using casting method. The relationship between the hydrogen bonding energy and the performances of thermoplastic starch film (TPSF), such as crystallinity, mechanical properties and water uptake determined experimentally, were revealed and discussed. The results indicated that glycerol/starch film contained strong hydrogen bonding interaction which could be increased by decreasing the temperature or increasing the glycerol content. The hydrogen bonding interaction is the key factor for the preparation of the plasticized starch material, and the plasticized mechanism can be interpreted according to the analytical results of the simulation.

Friedel–Crafts reaction of indoles to aromatic α-ketimino esters was found to be catalyzed by camphorsulfonic acid with good yields (up to 98%) under ambient temperature. This process provides an efficient method for the synthesis of unnatural amino acid derivatives that bear quaternary carbon centers.

AbstractA huge number of indolylglycine derivatives (III) bearing a tetrasubstituted carbon center is efficiently synthesized camphorsulfonic acid catalyzed.

The zinc(II) coordination polymer [Zn-3(BPT)(2)(mu(2)-H2O)(2)(H2O)(2)](n)center dot n(DMA) (1) (H3BPT = biphenyl-3,4 ',5-tricarboxylic acid, DMA = N,N '-dimethylactamide) was obtained by the solvothermal reaction of H3BPT with Zn(NO3)(2) in DMA/H2O mixed solvent. Single crystal X-ray analysis reveals that compound 1 has a complicated 3D framework containing linear trinuclear [Zn-3(COO)(4)(mu(2)-H2O)(2)] clusters as building subunits, which can be simplified into a (3,6)-connected rtl topological network with the Schlafli symbol {4.6(2)}(2){4(2).6(10).8(3)}. The calculated results of total and partial density of states (DOS) indicate that the luminescence of 1 mainly originates from intraligand charge transfer.