The piezoelectric strain of K_0.5Na_0.5NbO₃-based lead-free ceramic at different temperatures was studied. The Rayleigh analysis shows that the intrinsic and extrinsic contributions are increased at temperature from 173 to 298 K. In addition, a monoclinic phase structure was observed at 83 K. The results of phase field simulation show that the temperature dependent microstructure evolution is a function of the local structure size. This work contributes to understanding the structure and properties relationship of the multi-cations doped KNN-based piezoelectric ceramics as a function of temperature.

OER catalyst of Ni₃Fe/Ni₄S₃/Ni/C (NiFeSC series) mixed crystal composite nanofibers was prepared by electrospinning and atmospheric heat treatment process. The testing results indicate that the diameters of Ni₃Fe/Ni₄S₃/Ni/C composite nanofibers is about 200 nm, the grains size is about 1–3 nm, and the fiber surface is rough. The electrochemical test results show that the heterojunction of the prepared Ni₃Fe/Ni₄S₃/Ni/C hybrid crystal composite nanofiber has synergistic effect with sulfide, and exhibits good electrocatalytic activity of water decomposition and OER in alkaline system. The OER electrocatalytic performance of Ni₃Fe/Ni₄S₃/Ni/C composite electrode prepared via a heat treatment at 1 000 °C process was tested in 1 mol/L KOH electrolytes. The results show that the overpotential is about 298 mV, the Tafel slope is about 74 mV·dec⁻¹, and the surface resistance is about 1.69 Ω·cm², at the current density of 10 mA·cm⁻².

Novel hollow Au Ag alloy nano urchins were synthesized via Ag seeds growth method, and self-assembly coated on the wall and end-tip of silica fiber for fiber probe fabrication. The nano urchins homogeneously distributed on fiber surface because of fiber silanization. The sizes and tip sharpness of the nano-urchins could be controlled by Ag seeds. The elements distribution analysis indicated there was high Ag content in tip-top for better surface enhance Raman scattering performance. The detectable concentration could be as low as 10⁻⁸ M using crystal violet molecules as analyte. Moreover, the fiber probes were stable in air, due to Au in the alloy. This fiber probe could be used for low content single molecular analysis.

By adopting a homemade extension apparatus and wide-angle X-ray diffraction (WAXD) technique, the structural evolutions of the extracted ultra-high molecular weight polyethylene (UHMWPE) fibers with different spinning draw ratios were investigated during the poststretching process. Molecular chains oriented along the axis quickly at the early stage of drawing, which is quite different from the situation of drawing with solvents. The crystal regions, which have not melted at higher temperature, show stronger rigidity in the absence of solvents. Rigid characteristics show faster response to the external field. Also, the surface morphologies of fibers after poststretching are characterized by scanning electron microscopy (SEM). The lamellae stack disordered before stretching, but arranged in order along the draw direction when the draw ratios were larger than 1.

We studied a method to prepare a novel titanium dioxide (TiO₂) composite photocatalyst, starting from improving the separation efficiency of photogenerated electrons and holes. Regular TiO₂ microspheres were prepared by sol-gel method and loaded onto Ti₃C₂T _x (Mxene). The high electrical conductivity of Mxene was utilized to transfer photogenerated electrons quickly and effectively prevent their recombination. By adjusting the addition amount of Mxene, the hydrogen production efficiency of the sample was greatly improved, and the maximum efficiency reached 135.2 µmol·g⁻¹·h⁻¹, which was twice that of pure TiO₂. The nanocomposites were characterized by XRD, PL, TEM and SEM analysis and electrochemical methods, and the test proved that the improvement of hydrogen production efficiency was caused by the improvement of the separation efficiency of photogenerated electrons and holes. This work demonstrates the application of Mxene as a catalyst to improve efficiency and broadens the application prospects of Mxene.

The structure and characteristics of high-performance lightweight aggregates produced by high-carbon gasification slag were investigated by X-ray diffraction, scanning electron microscopy, thermogravimetry/differential thermogravimetr, differential scanning calorimetry-Fourier transform infrared, and mercury intrusion porosimetry, respectively. The experimental results show that the ceramsite undergoes two weightless stages in the calcining process. With the increase in the calcining temperature, a large number of pores are formed inside the ceramsite, its structure becomes denser, but the calcining temperature band of the ceramsite becomes narrow. The crystalline phase of the ceramsite changes at different calcining temperatures and the mineral phase changes from the earlieralbite, quartz, oligoclase, hematite, etc, to a silica-aluminum-rich glass phase. The 1 130 °C is a more suitable calcining temperature, and the cylinder compressive strength of ceramics is 11.59 MPa, the packing density, apparent density, porosity, and water absorption are 939.11 kg/m³, 1643.75 kg/m³, 28.11%, and 10.35%, respectively, which can meet the standards for high-strength lightweight aggregates.

Uniform monodispersed mesoporous silica nanospheres with vertical pores were successfully synthesized using chiral amphiphilic small molecule L-16Ala5PyClO₄ and solvents as dual templates via solgel transcription. The morphologies and pore sizes of silicas are adjustable by changing the type and amount of solvents in the reaction systems. With the increase of the organic solvent content, the morphologies of the obtained silica changed from nanospheres with vertical pore structures to nanosheets structures. When 1 mL of benzene, cyclohexane or toluene were used as solvents, only silica nanospheres were obtained, the BET surface areas of silica nanospheres reached 600.7, 669.5, and 560.8 m²/g, respectively. The pore sizes were 3.51, 3.54, and 3.46 nm, respectively. Significantly, these ordered silica nanospheres/poly(vinyl alcohol-co-ethylene) (PVA-co-PE) nanofiber membranes have high separation efficiencies (>99%) for n-hexane/water mixtures.

The fluorine-free MXene was prepared by Lewis acid salt etching of ternary layered ceramic MAX phase material. The structure of fluorine-free MXene was characterized by scanning electron microscopy (SEM) and X-ray diffractometry (XRD). The study finds that the layer spacing of fluorine-free MXene is approximately twice that of MXene etched by the liquid-phase method, compared to the conventional liquid-phase method. It also has greater capacitive properties. Therefore, the MXene prepared by this method shows a great potential for application in the field of capacitors.

Here a fluorescent probe based on a carbazole derivative (CNS) was developed to increase the detection range and reduce the detection limit of brilliant blue. Characteristics of CNS are studied. Due to the quenching ability of colorants, CNS shows an excellent current response to brilliant blue (from 1 to 10 µM) with a detection limit of 2.7×10⁻⁸ mol/L (3σ/k) in the conditions of a 1:1 volume ratio of water to tetrahydrofuran. And the stability and reproducibility of CNS in the detection of actual samples indicate great potential for application.

The research on asphalt performance mainly focused on the macro performance and micro mechanism. Mesoscopic analysis was introduced to study the effect of rubber powder movement on asphalt rubber properties. After the preparation parameters and the preparation process of asphalt rubber were determined, the modification mechanism and rheological properties were analyzed which revealed the compatible stability mechanism. Then, the analysis model of asphalt rubber was established to focus on simulating the effect of rubber powder and the spatial movement on its mechanical properties. The experimental results show that rubber powder can make the asphalt rubber bear more uniform stress distribution and enhance the ability to resist deformation. Meanwhile, the rotational motion and final distribution of rubber powder have an obvious impact on the mechanical properties of asphalt rubber. In the selected feature points, the average stress of rubber powder at 0° space angle is only 34.1% of that at 90° space angle. When the rubber powders are all in parallel in the ideal state, it enhances the mechanical properties the most. This study supplements the “mesoscopic” scale between macro and micro research. The relationship between micro mechanism and macro properties of asphalt rubber will be established from the mesoscopic perspective. It is also an effort to realize the effective correlation from micro, mesoscopic to macro in asphalt.

To reduce the coercive field of Na_0.5Bi_0.5TiO₃, BaTiO₃ were added as dopant materials. Then the (1−x)Na_0.5Bi_0.5TiO₃-xBaTiO₃ ceramic samples were produced in solid synthetic way. The optimum preparation condition and piezoelectric properties of the samples were investigated. The XRD results show that the fabric transites from rhombohedral to tetragonal gradually with the substitution of the Ba²⁺. The morphotropic phase boundaries (MPB) exists in the composition range of 0.06<x<0.10. The scanning electron microscopy (SEM) results show that the growth of the crystalline grain is restrained and the dimension of it turns finer. The study also shows that optimum calcined temperature is 900°C with x<0.06 and 950 °C with x⩾0.06. Suitable sinter temperature is 1 170 °C, and maintained time is 2 hours. Samples in the composition range of MPB exhibit the best piezoelectric performance. The test results show that the remanent polarization and the conceive field of the ceramics decease with the dope of Ba²⁺. In the composition range of MPB, the conceive field exhibits the lowest value.

The aim and scope of the present study were to determine the efficacy of UFFA in evaluating the workability, static and dynamic stabilization properties, retention period, and slump loss of SCC systems in their fresh state, as well as their compressive strength at various ages. Microstructure (SEM and XRD) of blended SCC systems were studied. Also, the thermogravimetry behavior of blended SCC specimens were researched. According to the evaluated results, incorporating up to 20% UFFA into fresh concrete improved its performance due to its engineered fine particle size and spherical geometry, both of which contribute to the enhancement of characteristics. Blends of 25% and 30% of UFFA show effect on the water-binder ratio and chemical enhancer dosage, resulting in a loss of homogeneity in fresh SCC systems. The reduced particle size, increased amorphous content, and increased surface area all contribute to the pozzolanic reactivity of the early and later ages, resulting in denser packing and thus an increase in compressive strength. The experimental results indicate that UFFA enhances the properties of SCC in both its fresh and hardened states, which can be attributed to the particles’ fineness and their relative effect on SCC.

The effects of coal metakaolin on the mechanical properties of high-belite sulphoaluminate cement under compressive loading were investigated. The composition and microstructure of hydration products at different hydration times were analyzed by X-ray diffraction and scanning electronic microscopy. The hydration process of blended cement was studied via electrochemical impedance spectroscopy. In particular, replacing a part of cement with CMK (10%, 20%, and 30%) was found to promote the hydration process, to refine the pore size, and to improve the compressive strength of the composite. The best compressive strength of the cement was achieved at a CMK content of 30% after 28 days hydration, being improved by 20.13 MPa, or 1.44 times relative to that of undoped specimens. Furthermore, the compressive strength is shown to correlate with the impedance parameter R_CCP, which allows the latter to be used for nondestructive assessment of the compressive strength of blended cement materials.

Aiming at the complex corrosion degradation factors of reinforced concrete and clearing the deterioration mechanism in the constant stress state, a new type of constant current accelerated corrosion method in the saline soil environment was developed. The three-dimensional paraffin isolation specimens and the three-dimensional penetration specimens were taken as the research objects, and the Cl⁻ content and AC impedance Bode diagram were measured. The macro morphology and micro analysis were also used to evaluate the corrosion degradation laws of the two groups of specimens. A constant current three-factor system accelerated model was established for the current acceleration factor, chloride ion, and sulfate ion acceleration factor. The experimental results show that, in the constant stress test of the saline soil environmental conditions, the paraffin isolation layer can effectively isolate corrosive chloride ions, which is a brand-new research method of single factor variable control in the constant stress test. According to the basic corrosion data, the law of constant current acceleration test is summarized and divided into five corrosion degradation stages, and each stage has significant changes in the accelerated corrosion efficiency. The corrosion degradation of a constant stress test is the combined effect of constant current, positive and negative penetration of chloride ions and sulfate ions.

In order to study the effect of PVA fiber on the dynamic and static mechanical properties of low-temperature freeze-thaw concrete under the saturated surface dry state, different contents of PVA fiber were added to prepare concrete in this experiment. The concrete was subjected to compression, flexural and SHPB impact tests combined with scanning electron microscopy for microstructure analysis, after different times of freeze-thaw cycles in the temperature range of 20–−70 °C. The experimental results show that the compressive strength of the PVA fiber reinforced concrete first increases and then decreases after freeze and thaw cycles, and the compressive strength is positively correlated with the fiber content. The flexural strength gradually decreases with freeze-thaw cycles. The flexural strength of the concrete with 1.2 kg/m³ of PVA fiber presents the lowest strength loss after 45 freeze and thaw cycles, which is about 14%. The dynamic failure strength gradually decreases with the increase of freeze-thaw times, and the reduction amplitude decreases with the increase of PVA fiber content. The best impact resistance is achieved when the PVA fiber dosage is 1.2 kg/m³.

In order to better understand the thermodynamic properties of magnesium oxysulfate (MOS) cement, pure reagent was analyzed to prepare magnesium sulfide cement, non-isothermal kinetics calculation of the main hydration products was also carried out, and the conversion process of magnesium sulfide cement 517 phase at different temperatures was investigated. Composition of magnesium sulfide cement prepared was measured by XRD technique, and decomposed by a comprehensive thermal analyzer, and DSC curves of magnesium sulfide cement under different temperature rising rates were processed by Kinssinger method and Dolye-Ozawa method. According to the TG-DSC curves of magnesium sulfide cement, the thermal decomposition reaction process can be divided into five stages under normal conditions. The DSC curve was processed by Kinssinger method and Dolye-Ozawa method, and the kinetic analysis was carried out to calculate the 517 phase activation energy of magnesium sulfide cement. The three stages correspond to different activation energies. Therefore, flame retardant mechanism and thermal decomposition mechanism of magnesium sulfide cement based materials are deduced.

A novel method for detecting early damage at the steel-concrete interface due to external loading based on AC impedance spectroscopy technology was proposed. Firstly, alkali pretreatment was introduced to ensure the accuracy and repeatability of the AC impedance test. Secondly, the AC impedance spectroscopy between the steel bar and concrete surface of different bonding positions was tested, and then the physical quantities reflecting the bonding damage condition were obtained by equivalent circuit fitting. Theoretical debonding position calculation and AC conductive structure analysis indicate that the change of interface resistance and interface capacitance can seize the development of bonding damage during the loading process. As the interface damage develops, obvious changes in interface resistance and interface capacitance are observed, and they cannot be recovered after unloading.

The present work uses PEO solution to well disperse carbon fiber and identifies percolation thresholds of carbon fiber and carbon black which are used as conductive fillers. The resultant cathode plates have an average compressive strength of 27.3 MPa and flexural strength of 29.09 MPa, which demonstrate excellent mechanical properties. The Cu²⁺ removal efficiency was measured at different current densities in EC process with cement-based cathode plate, while the voltage changes were recorded. The results showed that the cement-based cathode plate operated stably and achieved 99.7% removal of 1 L of simulated wastewater with a Cu²⁺ concentration of 200 ppm at a current density of 8 mA/cm² for 1 h. Characterization of floc and tested cathode plates, SEM and EDS analyses, and repeatability testing of the tested plates demonstrate the reusability of the plates, proving that cement-based plates can effectively replace metal cathode plates, reduce the cost of EC and improve the applicability of EC devices.

The mechanism of glutinous rice flour, a kind of natural admixture, on the hydration process, setting time, and microstructure of the Portland cement was investigated. The experimental results show that the glutinous rice flour has an obvious setting retarding effect on cement pastes. The optimal dosage of the glutinous rice flour is 3wt%. In this case, the initial and final setting time of the paste are delayed by 140 and 185 min, respectively. The flexural and compressive strengths of the hardened paste are increased by 0.35% and 0.07% after 56 d of curing. The glutinous rice flour hinders the mineral dissolution process and decreases the concentration of calcium ion at the initial stage of hydration due to the complexation effect, thereby hindering the nucleation and growth of CH and C-S-H phases and prolonging the hydration process. However, C-S-H phases combine with the glutinous rice flour to contribute the bonding effect together, which compacts the microstructure of hardened cement pastes at the later hydration stage of cement pastes. Thus, in-depth investigation on the utilization of glutinous rice flour as the admixture for the Portland cement is expected to be meaningful for the control of hydration exothermic rate and setting time.

A blast furnace slag zeolite (BFSZ) material was successfully synthesized from BFS by alkaline fusion and hydrothermal treatment. Via the analyses of XRD, FT-IR, FE-SEM, XRF, CEC and BET surface area measurement, when zeolite was synthesized at a crystallization temperature of 100 °C with initial Si/Al ratio of 1:1, the main composition in the product is Na-A zeolite. Under the above conditions, the BFSZ was synthesized with CEC of 3.06 meq/g and maximum BET surface area of 37.55 m²·g⁻¹. Moreover, the incorporating of BFS-derived minor metals (such as Mg, Fe, and Ca) are found to be of little importance for the synthesis of BFSZ. Thus the obtained BFSZ material has a great adsorption performance for removing Mn²⁺, Cu²⁺, and NH₄ ⁺ ions diluted in water, owing to the higher CEC.

The effect of solution and aging treatments on microstructure and mechanical properties of warm-rolled 7075 alloy was investigated via optical microscope, electron backscattered diffraction, transmission electron microscopy and tensile tests. The 7075 alloy was subjected to solution treatments at 450 °C for 1 h (ST1), 490 °C for 1 h (ST2) and 1.5 h (ST3). Three aging routes were carried out on samples from ST2: one-step (A1), two-step (A2), and three-step aging (A3). The experimental results show mainly recrystallized equiaxed grains in ST1 and ST3 state but a combination of elongated and equiaxed grains in ST2 condition. Three aged alloys have similar microstructures of sample ST2 while the recrystallization frequency gets decreased after aging. The least recrystallization fraction occurs in A2 state. Three aged 7075 alloys all possess enhanced strength and plasticity. Precipitates characterization reveals the maximum strength is achieved in A2 sample as the matrix precipitates are composed mainly of small η and many η′ phases. Aging route A2 appears preferable to other two aging conditions for attaining a pretty excellent combination of strength and plasticity.

To improve the wear resistance of the FeCoCrNiB_0.2 high entropy alloy (HEA), the FeCoCrNiB_0.2 (WC₀) and FeCoCrNiB_0.2 + 20wt% WC (WC₂₀) HEA coatings were prepared on Q235 steel by laser cladding (LC). The microstructure, hardness, and tribometer of the HEA coatings were investigated using scanning electron microscopy with spectroscopy (SEM/EDS), X-ray diffraction (XRD), vickers microhardness tester, and pin-on-disc tribometer, respectively. The experimental results show that the WC₀ HEA coating comprises a simple BCC phase mixed with an M₂B phase. Adding 20wt% WC, the WC₂₀ HEA coating is composed of a simple BCC phase mixed with the Cr₂₃C₆ carbide phase. The microstructure of the WC₂₀ HEA coating is simple, which consists of equiaxed grain and dendritic. The microhardness also increases from 625.5HV to 806.0HV, and the wear mass loss correspondingly decreases from 30.9 to 14.9 mg. W and C atoms formed by WC dissolution are mainly dissolved in the BCC phase, which leads to the solution strengthening effect. Besides, Cr₂₃C₆ carbides inhibit the growth of the grains, play the role of fine-grain strengthening, and further improve the hardness and wear resistance of the HEA coating.

AlCoCrFeNi_2.1 eutectic high entropy alloy (EHEA) and AlCoCrFeNi_2.1-xNbC (x=2.5wt%, 5.0wt%, 7.5wt%, and 10wt%) high entropy alloy (HEAs) were prepared by mechanical alloying (MA). The effects of milling time and NbC content on the alloying behavior and grain size of the AlCoCrFeNi_2.1 EHEA were investigated. The experimental results show that the AlCoCrFeNi_2.1 EHEA primarily consists of order BCC (B2) and face-centered-cubic (FCC) phases, while the AlCoCrFeNi_2.1-xNbC (x=2.5wt%, 5.0wt%, 7.5wt%, and 10wt%) HEAs are composed of B2, FCC, and NbC phases. With the increase of milling time, the powder goes through three stages, irregularity, cold welding fracture and spheroidization. The particle size of AlCoCrFeNi_2.1 EHEA powder shows a trend of first increasing and then decreasing. Therein, the particle size presents a normal distribution during 0–50 h alloying. With the addition of NbC, the AlCoCrFeNi_2.1-xNbC HEAs powders are significantly refined. And the degree of grain refinement gradually increases with the increase of NbC content.

Microstructure, texture evolution and strain hardening behaviour of the Mg-1Y and Mg-1Zn (wt%) alloys were investigated under room temperature compression. Microstructural characterization was performed by optical microscopy, scanning electron microscopy, electron back scattered diffraction and transmission electron microscopy. The experimental results show that Mg-1Zn alloy exhibits conventional three-stage strain hardening curves, while Mg-1Y alloy exhibits novel six-stage strain hardening curves. For Mg-1Y alloy, rare earth texture leads to weak tensile twinning activity in compression and consequently results in a moderate evolution to <0001> texture. Moreover, inefficient tensile twinning activity and weak slip-twinning interaction give rise to excellent ductility and high hardening capacity but low strain hardening rate. For Mg-1Zn alloy, basal texture leads to pronounced tensile twinning activity in compression and consequently results in rapid evolution to <0001> texture. The intense tensile twinning activity and strong slip-twinning interaction lead to high strain hardening rate but poor ductility and low hardening capacity.

The molten Cu60Ni35Co5 ternary alloy was undercooled by fluxing method and solidified by natural cooling method. The microstructure of all undercooled samples were analyzed. It is found that the rapidly solidified Cu60Ni35Co5 alloy has undergone two grain refinement phenomena within the undercooling range, and its microstructure and morphology change with the undercooling through the transformation process of “coarse dendrite — equiaxed dendrite — oriented fine dendrite — equiaxed crystal”. The refined structure with the maximum undercooling ΔT of 253 K was selected for electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) tests. EBSD results show that the refined structure contains a high proportion of large angle grain boundaries (LAGBs), a large number of randomly oriented grains, and high proportion of twins, while TEM results show that the dislocation density in most areas is relatively low. The above characteristics confirm that the solidification structure is refined due to recrystallization behavior under high undercooling.

Against protection requirements for high-speed fragments on the ground weapons, we carried out the research work of crushing mechanism at different impact speeds of φ8.7 mm spherical tungsten alloy, the penetration to 603 armor steel was completed by 20 mm ballistic gun, and the ANSYS/LS-DYNA software was used to complete the numerical calculation of the penetration. We find that there are different crushing mechanisms of spherical tungsten alloy with different speeds and low speed, the crushing mechanism of fragment is mainly controlled by overall plastic deformation, shearing stripping, and squeezing at a high pressure and a high speed. The crushing mechanism will have a spallation phenomenon in addition to the crushing mechanism under high pressure.

Effects of nucleation sites and diffusivity enhancement of chromium on reverted transformation of AISI 304 stainless steel during annealing process were investigated. Dynamics calculation revealed that the reverted transformation of strain-induced α’-martensite→γ austenite could were closely associated with active nucleation sites and diffusivity enhancement of chromium in nanocrystalline α’-martensite. The experimental data and the results were in accordance with 2-grain austenite/α’-martensite junctions calculated theoretically, which could result from high chromium diffusion rate in nanocrystalline α’-martensite. In addition, low temperature is not conducive to reversed transformation, while high temperature and long annealing time will lead to inhomogeneous grain size distribution.

The purpose of this work was to fabricate three-dimensional porous scaffolds by using the salt leaching technique. This technique is simple and it does not need the pressure or dislike expensive equipment. The study selected polycaprolactone blended with carboxymethylcellulose that is the additive. The ratios of them were derived from mixture design in Minitab program that was 98/2(P1), 93.5/6.5(P2), 89/11(P3), 84.5/15.5(P4), and 80/20(P5), respectively. The scanning electron microscopy (SEM) was applied to assess the physical properties and the pore size dimension of the scaffold from SEM micrographs. The results of SEM present the scaffolds happened interconnected porous structures that are found in all of the P1–P5 samples. The pore size dimension of all sample scaffolds is in the range of 264.11–348.28 µm. Whereas the largest and the smallest of pore size are the sample of P3 and P2, respectively, while the porosity ranges from 98.06%–98.88% that the sample of P5 is the greatest and the sample of P4 is the slightly lowest. In conclusion, the blended PCL/CMC scaffolds P1–P5 were formed by salt leaching technique suitable to use in tissue engineering application. However, the amount of CMC blended with PCL should be reasonable in order to adjust the hydrophilic of the scaffold.

A new protein wood adhesive was studied with Camellia oleifera protein. Formaldehyde and N-(2)-L-Ala-L-Gln (LAG) were used as the model compounds of amino resins and Camellia oleifera protein, aiming to provide scientific foundations for the improvement and applications of Camellia oleifera protein adhesive by the reaction of model compounds. The experimental results demonstrate that, under alkaline conditions, formaldehyde is easier to react with Camellia oleifera protein by quicker reaction and lower curing temperature. Under acid conditions, amino hydroxymethylated structure of aliphatic series from LAG is difficult to form stable reactive intermediates and further polycondensation. Hydroxymethylation of end acylamino and peptide bond amino from LAG is relatively weak. Under alkaline conditions, the free aliphatic amino and acylamino of LAG both can make hydroxymethylation reaction with formaldehyde. In the polycondensation, hydroxymethyl amide is the initial structure and the reactive intermediate is produced by E1cb reaction of hydroxymethyl amide. Methylene bridge bonds and methylene ether bonds are structures of the polycondensation products, which are competing reactions. The former is mainly formed by the reaction between alkaline reactive intermediate and amino of aliphatic series, and the latter is produced by the reaction of reactive intermediate and amino of hydroxymethyl aliphatic series with hydroxymethyl amide.

Six novel hydrolytically degradable polyesters were synthesized from thiodipropionic acid (TDPA) and five diols by melt polycondensation, and characterized by FT-IR, ¹H NMR, gel permeation chromatography, differential scanning calorimetry and thermogravimetry analysis. The polystyrene-equivalent number-average (M _n) and weight-average molecular weight (M _w) of these polyesters ranged from 4 900–11 100 Da and 7 900–20 879 Da, respectively, with PDI values of 1.48–1.98. The melting point varied from 62.3–127.9°C, and the 50% mass-loss temperature ranged between 387–417°C. The degradation of these polyesters was studied in terms of relative weight loss in distilled water at different pH. Weight losses of 14%–26% were obtained at pH 7.0, 26%–38% at pH 6.0, and 32%–43% at pH 8.3 over a 20-week period. The ecotoxicity study suggested that safety of the synthesized polyesters for the eisenia foetida. These results indicate that these polyesters have a combination of good thermal and degradability behaviors, which can be tailored through selection of the diol monomers used in the synthesis.