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THEORETICAL ANALYSIS OF kinetics OF NONISOTHERMAL crystallization OF POLYMERS

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Chinese Journal of Polymer Science 1994年第3期12卷 256-265页

作者：张志英 Department of Textile Chemical Engineering Tianjin Institute of Textile Science and Technology Tianjin 300160

The classical crystallization theories proposed by Avrami, Evans, and Mandelkern wereextended to the nonisothermal situation. The expressions derived from the classical equations canbe expressed in either the differential form or the integral form. A method was provided so as toobtain the parameters characterizing the crystallization rate and mechanism from DSC curves withseveral constant heating or cooling rates. The rate constants of crystallization obtained from bothisothermal and nonisothermal curves of poly(ethylene terephthalate)were compared.

关键词： crystallization kinetics Nonisothermal crystallization Avrami theory Poly (ethylene terephthalate)

kinetics OF NON-ISOTHERMAL crystallization

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Chinese Journal of Polymer Science 1990年第2期8卷 142-148页

作者：张志英曹振林 Department of Textile Chemistry Tianjin Institute of Textile Science and Technology Tianjin

A kinetic equation of non-isothermal crystamzation was derived by extending Avrami's equation to the non-isothermal situation. More crystallization information can be obtained from this kinetic equation. The curves of non-isothermal and isothermal crystallizations were analysed and compared for poly (ethylene terephthalate) (PET), and the results were discussed.

关键词： Non-isothermal crystallization crystallization kinetics Poly (ethyene terephthalate),Differential scanning calorimeter (DSC).

kinetics OF NON-ISOTHERMAL crystallization OF POLY (ETHYLENE TEREPHTHALATE) MODIFIED BY POLY (ETHYLENE GLYCOL)

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Chinese Journal of Polymer Science 1991年第4期9卷 318-325页

作者：张志英吴世臻杜莹华曹振林 Department of Textile Chemitry Tianjin Institute of Textile Science and Technology Tianjin

The non-isothermal crystallization kinetics of poly(ethylene terephthalate) (PET) modified by poly (ethlene glycol) (PEG) were determined by DSC. The dual linear regression method was used to evaluate the relationship between the reciprocal of t 1/2 ( the half life of crystallization) and the appropriate temperature variable. The parameters such as the activation energy (Ed) for transport, the equilibrium melting temperature (T_m^0),the nucleation parameter (ψ),themaximum crystallization temperature (T_(e, max)), and the kinetic crystallizability (G) for the copolyesters were obtained. The influence of the PEG content in PET chains on the parameters characterizing crystallization kinetics and crystallization thermodynamics was discussed.

关键词： Poly (ethylene glycol)/Poly (ethylene terephthalate) copolyester, Non-isothermal crystallization crystallization kinetics Differential scanning calorimetry (DSC)

ON A DIFFERENTIAL EQUATION FOR kinetics OF NON- ISOTHERMAL crystallization

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Chinese Journal of Polymer Science 1993年第2期11卷 125-132页

作者：张志英 Department of Textile Chemical Engineering Tianjin Institute of Textile Science and Technology Tianjin

A new differential equation was derived from the modified first-order kinetic model to describe the polymer crystallization processes. The crystallization experiments were carried out by means of DSC. Poly (ethylene terephthalate) resins were selected as the samples containing different catalysts. The relationships between the parameters obtained from the known Avrami equation and from one in the present paper were discussed. A method for applying the equation to determine the kinetic parameters from a constant heating and a constant cooling curve was proposed.

关键词： Non- isothermal crystallization crystallization kinetics Polymer Differential scanning calorimetry (DSC).

An investigation on crystallization property, thermodynamics and kinetics of wollastonite glass ceramics

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Journal of Central South University 2018年第8期25卷 1888-1894页

作者： SI Wei DING Chao School of Materials Science and Engineering Dalian Jiaotong UniversityDalian 116028China Dalian Environmental Monitoring Center Dalian 116023China

Wollastonite glass ceramics were prepared using the reactive crystallization sintering method by mixing waste glass powders with *** crystallization property,thermodynamics,and kinetics of the prepared wollastonite glass ceramics were determined by X-ray diffraction analysis,scanning electron microscopy,energy-dispersive spectroscopy,high-resolution transmission electron microscopy,and differential thermal *** showed that crystals of wollastonite and alumina could be found in the gehlenite through its reaction with silicon *** wollastonite crystals showed a lath shape with a certain length-to-diameter *** crystals exhibited excellent bridging and reinforcing *** the crystallization process,the aluminum ions in gehlenite diffused into the glass and the silicon ions in the glass diffused into ***,the three-dimensional frame structure of gehlenite was partially damaged to form a chain-like *** results of crystallization thermodynamics and kinetics indicated that crystallization reaction could occur spontaneously under a low temperature(1173 K),with 20 wt%gehlenite added as the reactive crystallization *** crystallization activation energy was evaluated as 261.99 kJ/mol by using the Kissinger *** compression strength of the wollastonite glass ceramic samples(7.5 cm×7.5 cm)reached 251 MPa.

关键词： glass ceramics crystallization thermodynamics crystallization kinetics

Preparation, crystallization and Mechanical Properties of Potassium Aluminosilicate Glass-ceramics

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Journal of Wuhan University of Technology(Materials Science) 2024年第3期39卷 587-595页

作者：郑伟宏黄猛 GAO Zipeng ZHANG Hang YUAN Jian TIAN Peijing PENG Zhigang State Key Laboratory of Silicate Materials for Architectures Wuhan University of TechnologyWuhan 430070China Shahe Research Institute of Glass Technology Shahe 054100China

In this study,transparent K_(2)O-Al_(2)O_(3)-SiO_(2)(KAS)glass-ceramics with leucite as the main crystalline phase were prepared by melting-quench method and two-step heat *** effects of SiO_(2)/Al_(2)O_(3) ratio and heat treatment on crystallization and mechanical properties were *** crystallization kinetics and X-Ray Diffraction(XRD)results showed that SiO_(2)/Al_(2)O_(3) ratio and heat treatment system had a direct impact on the crystallization behavior of potassium aluminosilicate *** heat-treated at 680℃/2 h and 780℃/1 h,cracks generated on the surface of the sample with the addition of SiO_(2)/Al_(2)O_(3)=4.8(in mol)due to the huge difference in the coefficient of thermal expansion between glass matrix and *** the addition of SiO_(2)/Al_(2)O_(3)(in mol)was 4,the sample with leucite as the main crystalline phase showed an excellent fracture toughness(1.46 MPa·m^(0.5))after the heat treatment of 680℃/2 h and 780℃/5 *** there was a phase transformation from kaliophilite to *** crystalline phases of the sample heat-treated at 680℃/8 h and 780℃/1 h were leucite and kaliophilite,which resulted in the visible light transmittance of 63%and the fracture toughness of 0.91 MPa·m^(0.5).Furthermore,after the heat treatment of 680℃/2 h and 780℃/5 h,the main crystalline phase of the sample with SiO_(2)/Al_(2)O_(3)=3.2(in mol)was still *** leucite only grows on the surface of the sample and is hard to grow inward,it is hard to achieve the bulk crystallization of leucite in the sample with SiO_(2)/Al_(2)O_(3)=3.2(in mol).

关键词： leucite glass-ceramic kaliophilite crystallization kinetics

Modulating perovskite crystallization and band alignment using coplanar molecules for high-performance indoor photovoltaics

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Journal of Energy Chemistry 2024年第11期98卷 383-390页

作者： Qu Yang Shuhan Fan Haozhe Zhang Zhenhuang Su Xingyu Gao Hui Shen Mingkui Wang Xiu Gong College of Physics &Guizhou Province Key Laboratory for Photoelectrics Technology and ApplicationGuizhou UniversityGuiyang 550025GuizhouChina State Key Laboratory of Public Big Data Guizhou UniversityGuiyang 550025GuizhouChina Shanghai Synchrotron Radiation Facility(SSRF) Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China Wuhan National Laboratory for Optoelectronics School of Optical and Electronic InformationHuazhong University of Science and TechnologyWuhan 430074HubeiChina

The proper bandgap and exceptional photostability enable CsPbI_(3) as a potential candidate for indoor photovoltaics(IPVs),but indoor power conversion efficiency(PCE) is impeded by serious nonradiative recombination stemming from challenges in incomplete DMAPbI_(3) conversion and lattice structure ***,the coplanar symmetric structu re of hexyl sulfide(HS) is employed to functionalize the CsPbI_(3) layer for fabricating highly efficient *** hydrogen bond between HS and DMAI promotes the conversion of DMAPbI_(3) to CsPbI_(3),while the copianar symmetric structure enhances crystalline ***,surface sulfidation during HS-induced growth results in the in situ formation of PbS,spontaneously creating a CsPbI_(3) N-P homojunction to enhance band alignment and carrier *** a result,the CsPbI_(3)&HS devices achieve an impressive indoor PCE of 39.90%(P_(in):334.6 μW cm^(-2),P_(out):133.5 μW cm^(-2)) under LED@2968 K,1062 lux,and maintain over 90% initial PCE for 800 h at ^(3)0% air ambient humidity.

关键词： Perovskite indoor photovoltaics CsPbI_(3) Coplanar symmetric structure molecules crystallization kinetics Hydrogen bond N-P homojunction

Glass formation adjacent to the intermetallic compounds in Cu-Zr binary system

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Journal of Materials Science & Technology 2018年第4期34卷 605-612页

作者： Yinxiao Wang Jiahao Yao Yi Li Shenyang National Laboratory for Materials Science Institute of Metal research Chinese Academy of Sciences

On the contrary to the common belief that glass formation is unfeasible near terminal intermetallic com- pound due to fast crystallization kinetics, here we present our findings that bulk metallic glasses are readily formed near intermetallic compounds, far away from the traditional region of glass forming near eutectics. While the intermetallic compounds themselves are not possible glass formers, bulk metallic glasses can be quenched compositionally neighboring the intermetallic compounds as close as 0.5 at.%. Taking binary Cu-Zr as a model system, the phenomenon of two optimum glass forming compositions sandwiching the corresponding intermetallic compounds （Cu51 Zr14, CU10Zr7, CuZr, CuZr2 and Cu8Zr3） is observed consistently. This new scenario of＂intermetallic glass＂ is verified by the thermodynamic princi- ple that the alloy liquids neighboring the intermetallic compounds possess lower Gibbs free energy than that of the compounds themselves. Furthermore, the sluggish crystallization behavior of these liquids provides an additional kinetic explanation.

关键词： Metallic glass Intermetallic Glass forming ability crystallization kinetics

Tailoring the crystallization Behavior and Mechanical Property of Poly(glycolic acid) by Self-nucleation

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Chinese Journal of Polymer Science 2022年第4期40卷 365-372页

作者： Jia-Xuan Li De-Yu Niu Peng-Wu Xu Zhao-Yang Sun Wei-Jun Yang Yang Ji Pi-Ming Ma The Key Laboratory of Synthetic and Biological Colloids Ministry of EducationJiangnan UniversityWuxi 214122China Inner Mongolia Pujing Polymer Material Technology Corporation Ltd. Baotou 014060China

Biocompostable poly(glycolic acid)(PGA)crystallizes slowly under fast cooling condition,leading to poor mechanical performance of the final *** this work,a self-nucleation(SN)route was carried out to promote the crystallization of PGA by regulating only the thermal procedure without any extra nucleating *** self-nucleation temperature(Ts)decreased from 250℃ to 227℃,the nuclei density was increased,and the non-isothermal crystallization temperature(Tc)of PGA was increased from 156℃ to 197℃ and the half-life time(t0.5)of isothermal crystallization at 207℃ was decreased by 89%.Consequently,the tensile strength and the elongation at break of the PGA were increased by 12%and 189%,*** to the change of Tc as a function of Ts,a three-stage temperature domain map(Domain I,II and III)was protracted and the viscoelastic behavior of the self-nucleation melt and the homogeneous melt was *** results indicated that interaction among PGA chains was remained in Domain IIb,which can act as pre-ordered structure to accelerate the overall crystallization *** work utilizes a simple and effective SN method to regulate the crystallization behavior and the mechanical properties of PGA,which may broaden the application range of resulting materials.

关键词： Poly(glycolic acid) Self-nucleation crystallization kinetics Mechanical property