Papers by Author: Bin Li

Abstract: Poly (trimethylene terephthalate) (PTT)/graphene oxide (GO) nanocomposites were prepared by melt mixing. The effect of GO on non-isothermal melt crystallization kinetics of PTT with different amounts of GO were investigated by differential scanning calorimetry (DSC). The Avrami, Ozawa and Mo were used to analyze the non-isothermal crystallization process. The results of Avrami analysis showed that adding GO into PTT matrix changed the crystallization nucleation of PTT. Ozawa analysis could not be used for the non-isothermal crystallization of PTT/GO nanocomposites. According to the results of Mo analysis, a higher cooling rate would be needed in order to obtain a higher degree of crystallinity at unit crystallization time.

Abstract: Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/functionalized graphene blends were prepared by solution blend method. The structure, thermal properties, thermal degradation and crystalline morphology were studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetry (TG), and polarizing optical microscopy (POM) analyses. Experimental results indicated that FGO increase the intensity of diffraction peak. Small-sized PHBV spherulites were formed. FGO affects the crystallization behavior of PHBV as heterogeneous nucleation agent. FGO acts as an effective thermal barrier due to its large aspect ratio and thereby hinders the degradtion of PHBV.

Abstract: Ferromagnetic glass ceramics with magnetism and biological activity could be used for magnetic induction hyperthermia. In this study Fe₂O₃-CaO-SiO₂ glass-ceramics were prepared by sol-gel method. The sample was characterized by X-ray diffraction (XRD) and differential thermal analysis (DTA). The results showed that the major phases of the sample are wollastonite and magnetite and the crystallization activation energy of sample is 189.3KJ/mol, which would provide a theoretical basis for the establishment of the optimum process conditions of heat treatment technology.

Abstract: The glass ceramics were prepared by using molybdenum slag (90wt% added) as the raw materials, in which TiO₂ functioned as the nucleation agent. The effect of TiO₂ additions on the crystallization was studied. The crystallization process was investigated by DTA, XRD and SEM. It was showed that TiO₂ can effectively promote the glass formation when the content of TiO₂ is 5wt %. The activation energy for crystal growth E=280.46kJ/mol was evaluated by DTA and kinetic method. The glass ceramic has good properties with main crystal phase of wollastonite.

Abstract: Ag₂O-CaO-Fe₂O₃-SiO₂ glass-ceramic was prepared by the sol-gel method. Differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) were used to investigate crystallization process of Ag₂O-CaO-Fe₂O₃-SiO₂ glass. The kinetic results show that the values of the activation energy and frequency factor of the glass are 441.991 KJ/ mol and 1.58×10²⁰, respectively. And the dimensionality of crystal growth, n, decreases as the heating rate increases. The crystalline phases of the glass-ceramic are magnetite, wollastonite and minor hematite. The saturation magnetization and coercive force of the heat-treated glass are 0.08 Wb/m² and 14 KA/m at room temperature. The glass-ceramic has some capacity of anti-microbial.

Abstract: Pyrophyllite was the cheap, environmentally friendly alumina silicate clay minerals. This paper studied optimization of conditions for extraction of acid-soluble Al₂O₃ from pyrophyllite. Qualitative tests had been performed in studying pyrophyllite crystal at different temperatures by using scanning electron microscopy. Dissolution experiments showed that after thermal activation the behavior of alumina in acid the dissolution was different, which was affected by hydrochloric acid concentration, heat activation temperature and acid leaching time. When the calcinations temperature was 700 °C and hydrochloric acid concentration was 25%, the dissolution amount of alumina largest. The fit results indicated that the research for the relationship between dissolution and time by Using Exponential function series Asymptotic1 model to fitting match was the best. So the above function could be used to estimate each time the dissolution of alumina from pyrophyllite in hydrochloric acid.

Abstract: This paper studied the influence of heat treatment on the pyrophyllite structure and acid-soluble properties of alumina. Qualitative tests had been performed in studying pyrophyllite crystal at different temperatures by XRD, TG-DTA, FT-IR and quantitative analysis of Al2O3. The quantitative titration method studied the dissolve characteristics of the different heat treatment samples in different acid conditions, and then a numerical simulation was done. The results showed that at temperatures below 480 °C, the pyrophyllite did not change the basic structure. 480~700 °C dehydroxylation reaction occurred, and the structure water of pyrophyllite is removed, and then turned into partial pyrophyllite. Dissolution experiments showed that after thermal activation the behavior of alumina in acid the dissolution was different, which was affected by hydrochloric acid concentration, heat activation temperature and acid leaching time. When the calcinations temperature was 700 °C, the dissolution amount of alumina was largest. These works could provide some theoretical basis for further application of pyrophyllite research.

Abstract: Ti-bioglass was sprayed on Ti6Al4V substrate. The crystallization dynamics of Ti-bioglass was analyzed by differential scanning calorimetry(DSC). The structure and morphology of the coatings were studied by SEM, TEM and AFM. The results showed that new phase Ca5(PO4)3F formed at 695.2°C when bioglass crystallized. The formation activation energy was 147.76KJ/mol and the crystallization exponent was less than 3 (n<3). It indicated that the crystallization happened on the surface. When 20 wt% bioglass was mixed with Ti powders, the formation activation energy was 324.6KJ/mol and the crystallization exponent was larger than 3 (n>3), which indicated that an integrated crystallization happened. Micro- or nano-scale R-TiO2, A-TiO2 and Na2Ti6O13 crystals precipitated on the surface of the coating after crystallization treatment. These crystals have a function of self-seal on the cracks on the coatings and form a metallurgical interface between the substrate and the coating.