郭少云
从事高分子力化学、聚合物加工新技术、聚合物及其共混复合材料增强增韧新途径、聚合物及其共混复合材料在加工过程中的形态控制等领域的研究
个性化签名
- 姓名:郭少云
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学术头衔:
博士生导师
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学科领域:
材料科学
- 研究兴趣:从事高分子力化学、聚合物加工新技术、聚合物及其共混复合材料增强增韧新途径、聚合物及其共混复合材料在加工过程中的形态控制等领域的研究
郭少云,男,1962年3月生,湖北钟祥市人,中共党员,教授,材料学博士生导师。1992年6月毕业于成都科技大学(现四川大学)高分子研究所,获工学博士学位。1995晋升为高分子材料工程国家重点实验室、四川大学高分子研究所教授,1996年加拿大Laval大学化工系作高访学者。现任高分子材料工程国家重点实验室、四川大学高分子研究所教授,博士生导师,复合材料学报编委,聚氯乙烯编委会副主任委员,中国复合材料学会理事,全国塑料标准化技术委员会石化塑料树脂产品分会委员,中国复合材料学会聚合物基复合材料分会常务委员等。主要从事高分子力化学、聚合物加工新技术、聚合物及其共混复合材料增强增韧新途径、聚合物及其共混复合材料在加工过程中的形态控制等领域的研究。主要学术成绩:作为项目负责人承担了国家863、国家自然科学基金、国际合作项目、教育部优秀年轻教师基金、教育部骨干教师基金、四川省重点项目等国家、部委及企业委托项目近30项,此外作为项目主要研究人员承担国家973、国家自然科学基金重点项目等国家项目5项。有多项成果已转化为工业化生产。获得的奖励有:1998年教育部科技进步奖一等奖,1993年国家教委科技进步奖二等奖,1996年中国化学会青年化学奖,1995年宝钢优秀教师奖,1995年四川省青年科技奖,2000年四川省优秀青年,1991年中石化科技进步奖三等奖,1994年成都市优秀青年教师等。申请中国发明专利9项,其中4项已授权。发表论文100余篇。
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郭少云, HONG WU, , SHAOYUN GUO, *, ZHEN LI
Journal of Polymer Science: Part B: Polymer Physics, Vol. 43, 2121-2129 (2005),-0001,():
-1年11月30日
In this work, the effect of ultrasonic irradiation on molecular structure development of metallocene-catalyzed linear low density polyethylene (mLLDPE) was studied. GPC results show that ultrasonic irradiation have influence on molecular weight and molecular weight distribution of mLLDPE. Molecular weight of mLLDPE decreases slightly at the initial 30s of ultrasonic irradiation and then increases obviously; its distribution becomes wider with the increase of ultrasonic irradiation time. The power and frequency of ultrasonic irradiation have the distinct influence on molecular weight and its distribution of mLLDPE. DSC results show that ultrasonic irradiation has distinct influence on multiple step crystallizing behaviors of mLLDPE because of the change of branched chain in mLLDPE molecules. Thermal stability of mLLDPE is improved greatly because of micro-crosslinking structure in mLLDPE molecule, which is formed in the presence of ultrasonic irradiation. A possible mechanism for molecular structure development of mLLDPE in the presence of ultrasonic irradiation is also proposed in this paper.
ultrasonic irradiation, molecular structure, mLLDPE
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郭少云, Jiang Li, Mei Liang, Shaoyun Guo, Ying Lin
Polymer Degradation and Stability 86(2004)323-329,-0001,():
-1年11月30日
The ultrasonic degradation of polyamide 6 (PA6) melt was conducted in a specially designed reactor. The effects of initial molecular weight of PA6, irradiation time, ultrasonic intensity as well as ultrasonic irradiation distance on the ultrasonic degradation of PA6 melt were investigated. Some surprising experimental results show that for low molecular weight PA6 (LPA6), the viscosity-average molecular weight of LPA6 increases in the presence of ultrasonic oscillations due to extension reaction of end groups (eCOOH and eNH2), while for high molecular weight PA6 (HPA6), the viscosity-average molecular weight of HPA6 decreases with irradiation time, and passes through a minimum, then increases with irradiation time, up to a limiting molecular weight. Ultrasonic degradation kinetics of HPA6 melt obey the equation: Mt% MNCAe kt: FTIR analysis and a microtitration method confirm that the chain scission of HPA6 under ultrasonic irradiation occurs at CeN bonds. A plausible ultrasonic degradation model of the polymer melt based on molecular movement is proposed. Published by Elsevier Ltd.
Ultrasound, Degradation, Polyamide 6, Mechanochemical, Kinetics
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郭少云, YUNTAO LI, GUANGSHUN CHEN, SHAOYUN GUO, AND HUILIN LI
Journal of Macromolecular Sciencew, Part B: Physics, 45: 39-52, 2006,-0001,():
-1年11月30日
The effects of ultrasonic oscillations on properties and structure of extruded highdensity polyethylene (HDPE) were studied. The experimental results show that ultrasonic oscillations can improve the surface appearance of the HDPE extrudates; increase the productivity of the HDPE extrudates; and decrease the die pressure, melt viscosity, and flow activation energy of the HDPE. The processing properties of the HDPE improve greatly in the presence of ultrasonic oscillations. Linear viscoelastic properties tests show that dynamic shear viscosity and zero shear viscosity decrease in the presence of ultrasonic oscillations. Ultrasonic oscillations can improve crystal perfection and thermal stability of HDPE. At appropriate ultrasound intensity, ultrasonic scillations could also increase the mechanical strength of extruded HDPE. The gel permeation chromatography (GPC) results show that at high ultrasound intensity and low rotation speed of extrusion, ultrasonic oscillations causes chain scission of HDPE, which result in a decrease of molecular weight and an increase of melt flow index.
HDPE, ultrasonic oscillations, properties, structure
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郭少云, Hong Pi, Ying Xiong, and Shaoyun Guo*
Polymer-Plastics Technology and Engineering, 44: 275-288, 2005,-0001,():
-1年11月30日
The effects of nine kinds of transition metal oxides on the elimination kinetics of hydrogen chloride (HCI) during thermal decomposition of polyvinyl chloride (PVC) at 210℃ were investigated using online measurement of conduc-tivity. It was found that the presence of TiO2, V2O5, Cr2O3, and MoO3 obviously decreases the elimination rate of HCI and the amount of HCI released by a factor of 10-20 times, indicating that they have a strong inhibiting effect on the release of HC1. The presence of MnO2, ZnO, CuO, C0203, and Fe203 promotes the elim-ination of HCI during thermal decomposition of PVC. The maximum elimination rate of HCI in PVC/ZnO, especially, is ca.10 times as high as that of PVC. In this work, the LnLn kinetic model, Ln(l-X)=-ktn, describes the kinetics of elimin-ation of HCI during thermal decomposition of PVC. The elimination rate of HC1 during thermal decomposition of PVC increases with the rise of the apparent order of reaction, n, in this model nvalue well describes the elimination kinetics of HC1 during thermal decomposition of PVC.
Transition metal oxides, PVC, thermal decomposition, kinetics, elimination of hydrogen chloride
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郭少云, Chang Lu, Xiaofeng Yu, Shaoyun Guo
POLYMER ENGINEERING AND SCIENCE-2005,-0001,():
-1年11月30日
The effect of melt temperature, ultrasonic oscillations, and induced ultrasonic oscillations modes on weld line strength of polystyrene (PS) and polystyrene/polyethylene (PS/HDPE)(90/10) blend was investigated. The results show that the increase of melt temperature is beneficial to the increase of weld line strength of PS and PS/HDPE blend. Compared with PS, the increase of melt temperature can greatly enhance the strength of PS/HDPE blends. For PS, the presence of ultrasonic oscillations can enhance the weld line strength of PS at different melt temperatures. But for PS/HDPE blends, the presence of ultrasonic oscillations can improve the weld line strength when the melt temperature is 230℃, but when the melt temperature is 195℃, the induced ultrasonic oscillations hardly enhance the weld line strength. Compared with Mode I (ultrasonic oscillations were induced into the mold at the whole process of injection molding), the induced ultrasonic oscillations as Mode II (ultrasonic oscillations were induced into the mold after injection mold filling) is more effective at increasing the weld line strength of PS and PS/HDPE blends. The mechanism for ultrasonic improvement of weld line strength was also studied. POLYM. ENG. SCI., 45: 1666-1672, 2005.
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郭少云, Lijuan Zhao, Jiang Li, Shaoyun Guo*, Qin Du
Polymer 47(2006)2460-2469,-0001,():
-1年11月30日
Polypropylene/montmorillonite nanocomposites (PPCNs) with 3% organophilic montmorillonite (OMMT) content were prepared via ultrasonic extrusion. The objective of present study was to investigate the effects of ultrasonic oscillations in processing on the morphology and property development of PPCNs. XRD and TEM results confirmed the intercalated structure of OMMT in conventional nanocomposite (without ultrasonic treatment) and ultrasonicated nanocomposite, but ultrasonic oscillations could make silicate layers finely dispersed and a little exfoliated. According to SEM, the OMMT particles were evenly and finely dispersed in the ultrasonicated nanocomposite via ultrasonic oscillations, and the aggregation size of clay particles was about 100nm, which is less than that in conventional nanocomposite. The crystalline dimension, crystalline morphology and the growth rate of crystallization in PPCNs were investigated by DSC and PLM, it was found that the OMMT particles and ultrasonic oscillations played an important role in the nucleation rate, crystallization temperature and spherulite size of PP matrix in nanocomposites. Compared with conventional nanocomposite, the mechanical properties of the ultrasonicated nanocomposite increased due to the improved dispersion of OMMT and diminished spherulite size. The thermal stability and the rheological behavior of PP and its nanocomposites were both studied by thermogravimetry and high pressure rheometer, respectively.
Polypropylene, Montmorillonite, Nanocomposites
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郭少云, Chang Lu, Shaoyun Guo*, Li Wen, Junyou Wang
European Polymer Journal 40(2004)2565-2572,-0001,():
-1年11月30日
The effeect of weld line on the morphology and mechanical properties of 70/30 polystyrene and polyamide-6 blends with various amounts of poly (styrene-co-maleic anhydride)(SMA) as compatibilizer was investigated. For blends without or with low content of SMA, the dispersed domains near the weld line were elongated parallel to the weld line; and the dispersed domains in weld line were spherical. But for blend with high content of SMA, the isotropic morphology was observed. And the dierence of morphology at weld line caused the distinction of fracture mechanism. The tensile strength of the blend is greatly influenced by the morphology of dispersed domains at weld line. While the morphology has only slight effect on impact strength of the blends.
Weld line, Polystyrene/, Polyamide-6 blends, Morphology, Mechanical strength
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【期刊论文】Ultrasonic Preparation of Polymer/Layered Silicate Nanocomposites during Extrusion
郭少云, Jiang Li, Lijuan Zhao, Shaoyun Guo
Polymer Bulletin 55, 217-223 (2005),-0001,():
-1年11月30日
Three kinds of polymer/layered nanocomposites were prepared via ultrasonic extrusion. Experimental results showed that ultrasonic oscillations could mostly decrease the size and its distribution of clay particles in polymer matrix. Therefore, crystal size of polymer matrix decreases. For PA6-based nanocomposites with higher compatibility, the ultrasonic oscillations can also affect the microstructure of clay, causing more regions of exfoliated clay. Due to better dispersion of clay and smaller crystal size, the elongation at break of polymer/layered nanocomposites ultrasonically treated got greatly increased, meanwhile ultrasonic oscillations also improved their other mechanical properties, such as tensile and impact strength.
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【期刊论文】Degradation kinetics of polystyrene and EPDM melts under ultrasonic irradiation
郭少云, Jiang Li, Shaoyun Guo*, Xiaonan Li
Polymer Degradation and Stability 89(2005)6-14,-0001,():
-1年11月30日
The ultrasonic degradation of polystyrene (PS) and ethyleneepropylene diene monomer (EPDM) melts was conducted in a specially designed reactor. A degradation model of polymer melts was proposed to explain the ultrasonic degradation, and degradation of polymer melts is treated as a mechanochemical process. Ultrasonic degradation kinetics obeys the equations: MTZMNCA e kt or ½h tZ½h NC ½h 0 ½h N e kt. The experimental results show that the molecular weight or intrinsic viscosity of polymer melts decreased with ultrasonic irradiation time and approached a limiting value, below which no further degradation took place. Dierent from ultrasonic degradation of polymer solutions, the scission of chains in polymer melts is random in the initial stage, and then non-random. FTIR spectra of samples ultrasonically treated and untreated confirmed that the initial product of ultrasonic degradation in polymer melts is a macroradical. The effects of ultrasonic intensity and reaction temperature on degradation of PS and EPDM melts were also investigated. The significant results showed that the degradation rate, the limiting value and degradation extent are correlated greatly with the experimental conditions.
Ultrasound, Degradation, Polystyrene, Ethyleneepropylene diene monomer, Melt
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郭少云, Guangshun Chen, Shaoyun Guo, Yuntao Li
Journal of Applied Polymer Science, Vol. 92, 3153-3158 (2004),-0001,():
-1年11月30日
The linear rheological properties of highdensity polyethylene (HDPE), polystyrene (PS), and HDPE/PS (80/20) blends were used to characterize their structural development during extrusion in the presence of ultrasonic oscillations. The master curves of the storage shear modulus (G) and loss shear modulus (G) at 200℃ for HDPE, PS, and HDPE/PS (80/20) blends were constructed with time-temperature superposition, and their zero shear viscosity was determined from Cole-Cole plots of the outof-phase viscous component of the dynamic complex viscosity versus the dynamic shear viscosity. The experimental results showed that ultrasonic oscillations during extrusion reduced G and G as well as the zero shear viscosity of HDPE and PS because of their mechanochemical degradation in the presence of ultrasonic oscillations; this was con-firmed by molecular weight measurements. Ultrasonic oscillations increased the slopes of log G versus log G for HDPE and PS in the low-frequency terminal zone because of the increase in their molecular weight distributions. The slopes of log G versus log G for HDPE/PS (80/20) blends and an emulsion model were used to characterize the ultrasonic enhancement of the compatibility of the blends. The results showed that ultrasonic oscillations could reduce the interfacial tension and enhance the compatibility of the blends, and this was consistent with our previous work.
rheology, blends
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