The effects of interfacial modifier on the mechanical, dynamic mechanical properties and crystallization behavior of the polyethylene composites were investigated in the present paper. It was found that the interfacia...The effects of interfacial modifier on the mechanical, dynamic mechanical properties and crystallization behavior of the polyethylene composites were investigated in the present paper. It was found that the interfacial modifer significantly improved the mechanical properties, influenced the dynamic mechanical spectra and slightly changed the crystallization behavior. The results showed that the interfacial modifier changed the dispersion state of dispersed phase of the composites, resulting in different phase structure, which was the major reason leading to different mechanical and crystallization properties.展开更多
Our work aims to evaluate a complete outlook of virgin high density polyethylene (HDPE) and polypropylene (PP) polyblends. Virgin PP of 20, 30 and 50 weight% is compounded with virgin HDPE. The properties like tensile...Our work aims to evaluate a complete outlook of virgin high density polyethylene (HDPE) and polypropylene (PP) polyblends. Virgin PP of 20, 30 and 50 weight% is compounded with virgin HDPE. The properties like tensile strength, flexural strength, Izod impact strength are examined. Scanning electron microscopy (SEM) and polarised light microscopy (PLM) are used to observe the surface and crystal morphology. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) tests verify the non compatibility of both polymers. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques are used to study the thermal behaviour of composites. The results manifest co-occurring spherulites for polyblends;indicating the composite to be a physical blend of continuous and dispersed phases, but on the other hand PP improves the tensile and flexural properties of HDPE.展开更多
The objective of this study of modified polypropylene (PP) fibres using nanoadditives (nano-CaCO3 and Cloisite 30B) was to determine the influence of these additives on thermal and mechanical properties, but especiall...The objective of this study of modified polypropylene (PP) fibres using nanoadditives (nano-CaCO3 and Cloisite 30B) was to determine the influence of these additives on thermal and mechanical properties, but especially on the barrier properties of the nanocomposite fibres against UV radiation. The DSC data obtained from measurements of PP/CaCO3 or PP/C30B nanocomposite fibres were used for determination of the constants n and K of the Avrami equation and in the estimation of other thermal properties of the fibres, such as their crystallization half-time t1/2, rate of crystallization t1/2, the necessary time for maximum crystallization tmax and free energy per unit area of surface in the lamella perpen-dicular to the axis of a high-molecular chain se. The nano-CaCO3 or Closite 30B fillers (pre-treated separately in three different solvents: glycerine, acetone and water) did not influence the melting temperatures but caused an increase in PP crystallization temperatures in comparison with the pure PP fibres. The pre-treatments of nanoadditives resulted in increase of n, K, t1/2 values and decrease of t1/2, tmax as well as the values of free surface energies per unit area of the modified PP fibres. There was also observed a decrease in the mechanical properties, however, there was an increase of barrier properties against UV radiation of nanocomposite PP fibres in comparison with neat PP fibres, which was one of the main objectives of the study.展开更多
A series of new glass compositions based on PbX2 (X: Cl, Br or I) have been studied. Binary and ternary glasses resulted from the association of PbI2, Pb-Cl-2, AgI, KCl and KBr. By means of differential scanning calor...A series of new glass compositions based on PbX2 (X: Cl, Br or I) have been studied. Binary and ternary glasses resulted from the association of PbI2, Pb-Cl-2, AgI, KCl and KBr. By means of differential scanning calorimetry (DSC), the mechanism and kinetics of crystallization process were studied. X-ray diffraction studies demonstrate that there is the formation of complicated crystalline phases in crystallized lead iodide based glasses. By heat treating halide glasses of appropriate composition under adequate heating temperature and duration, the lead iodide based glasses could be converted into glass-ceramics with microcrystal size less 1 mu m of which mechanical properties are improved.展开更多
基金This work was supported by a Fund for Young Scientist from the National Advanced Materials Committee of China(NAMCC)
文摘The effects of interfacial modifier on the mechanical, dynamic mechanical properties and crystallization behavior of the polyethylene composites were investigated in the present paper. It was found that the interfacial modifer significantly improved the mechanical properties, influenced the dynamic mechanical spectra and slightly changed the crystallization behavior. The results showed that the interfacial modifier changed the dispersion state of dispersed phase of the composites, resulting in different phase structure, which was the major reason leading to different mechanical and crystallization properties.
文摘Our work aims to evaluate a complete outlook of virgin high density polyethylene (HDPE) and polypropylene (PP) polyblends. Virgin PP of 20, 30 and 50 weight% is compounded with virgin HDPE. The properties like tensile strength, flexural strength, Izod impact strength are examined. Scanning electron microscopy (SEM) and polarised light microscopy (PLM) are used to observe the surface and crystal morphology. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) tests verify the non compatibility of both polymers. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques are used to study the thermal behaviour of composites. The results manifest co-occurring spherulites for polyblends;indicating the composite to be a physical blend of continuous and dispersed phases, but on the other hand PP improves the tensile and flexural properties of HDPE.
文摘The objective of this study of modified polypropylene (PP) fibres using nanoadditives (nano-CaCO3 and Cloisite 30B) was to determine the influence of these additives on thermal and mechanical properties, but especially on the barrier properties of the nanocomposite fibres against UV radiation. The DSC data obtained from measurements of PP/CaCO3 or PP/C30B nanocomposite fibres were used for determination of the constants n and K of the Avrami equation and in the estimation of other thermal properties of the fibres, such as their crystallization half-time t1/2, rate of crystallization t1/2, the necessary time for maximum crystallization tmax and free energy per unit area of surface in the lamella perpen-dicular to the axis of a high-molecular chain se. The nano-CaCO3 or Closite 30B fillers (pre-treated separately in three different solvents: glycerine, acetone and water) did not influence the melting temperatures but caused an increase in PP crystallization temperatures in comparison with the pure PP fibres. The pre-treatments of nanoadditives resulted in increase of n, K, t1/2 values and decrease of t1/2, tmax as well as the values of free surface energies per unit area of the modified PP fibres. There was also observed a decrease in the mechanical properties, however, there was an increase of barrier properties against UV radiation of nanocomposite PP fibres in comparison with neat PP fibres, which was one of the main objectives of the study.
基金This project was supported by the National Natural Science Foundation of China and the Foundation of the State Commission of Education
文摘A series of new glass compositions based on PbX2 (X: Cl, Br or I) have been studied. Binary and ternary glasses resulted from the association of PbI2, Pb-Cl-2, AgI, KCl and KBr. By means of differential scanning calorimetry (DSC), the mechanism and kinetics of crystallization process were studied. X-ray diffraction studies demonstrate that there is the formation of complicated crystalline phases in crystallized lead iodide based glasses. By heat treating halide glasses of appropriate composition under adequate heating temperature and duration, the lead iodide based glasses could be converted into glass-ceramics with microcrystal size less 1 mu m of which mechanical properties are improved.
