Zheng Yan

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Name: 严正; Yan, Zheng
Organization: Sichuan University , China
Department:
Title: Associate Professor(PhD)

TOPICS

Co-reporter:Ying Lu;Huan Peng;Kaizhi Shen
Polymer Bulletin 2011 Volume 66( Issue 1) pp:147-164
Publication Date(Web):2011 January
DOI:10.1007/s00289-010-0317-7
A vibration force field had been introduced during the polymer injection processing in the article, which caused some physical properties of the articles were significantly improved. The creep behavior of calcium carbonate-filled polypropylene (PP/CaCO3) prepared at different vibration condition was studied in order to reveal the influence of vibration conditions on the creep behavior. First, the tensile creep behavior of the PP/CaCO3 prepared at different vibration conditions has been investigated with a tensile creep apparatus, and it had been observed that with the vibration frequency increasing, the tensile strain would be maximum value at 0.72 Hz. While the tensile strain of the PP/CaCO3 prepared at different vibration pressure would be decreasing with the vibration pressure increasing. Then the wide-angle X diffraction (WAXD) and the differential scanning calorimeter (DSC) were used to explore the microstructure of the PP/CaCO3 article prepared at different vibration condition. According to the WAXD and DSC data, the number of the crystal grain may play an important role on the change of the creep behaviors of PP/CaCO3 article prepared at different vibration conditions. Finally, the inner reason why the different vibration condition would cause different creep behavior could be found that if the number of the crystal grain is larger, then there would be stronger physical cross-linking structure, which causes stronger anti-creep ability.
Co-reporter:Ying Lu;Huan Peng;Kai-Zhi Shen
Polymer Engineering & Science 2009 Volume 49( Issue 3) pp:454-461
Publication Date(Web):
DOI:10.1002/pen.21304

Abstract

The influence of vibration pressure and frequency on the mechanical properties and stress-relaxation was investigated via stress-relaxation test and tensile test. First, it had been observed in the tensile test that the tensile fracture elongation reached the maximum at 20 Hz for polypropylene (PP) and 15 Hz for polypropylene/calcium carbonate (PP/CaCO3), respectively. With the increasing vibration pressure, the tensile fracture elongation would decrease. Second, the dynamic mechanic analysis has been used to test loss angle tangent value of the material. After the dynamic mechanic analysis, the simples have been installed in the universal tensile testing machine which applies the 2% strain on the simples. From these experiments, it has been discovered that the trend of the changes of stress-relaxation is similar with the trend of the changes of loss angle tangent value. When the vibration frequency reaches the 20 Hz for PP and 15 Hz for PP/CaCO3, the stress-relaxation is larger than that of other materials prepared at the same pressure (10 Mpa); meanwhile, the stress-relaxation of these materials, which has been prepared at the same frequency (10 Hz), decreases with the increasing vibration pressure. According to above tests, it is also very useful to improve the stress relaxation properties via changing the condition of the vibration field. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers

POLY[OXY[(1R)-1-METHYL-2-OXO-1,2-ETHANEDIYL]]
Poly[oxy[(1S)-1-methyl-2-oxo-1,2-ethanediyl]]
Poly[oxy(1,4-dioxo-1,4-butanediyl)oxy-1,4-butanediyl]
1,4-Butanediol-succinic acid copolymer