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EFFECT OF PAN-MILLING ON RHEOLOGICAL PROPERTIES OF high density polyethylene

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Chinese Journal of Polymer Science 2000年第5期18卷 397-403页

作者： Hua Huang Polymer Research Institute, Sichuan University, Chengdu 610065, China 四川大学四川成都

The effect of pan-milling on the rheological properties of high density polyethylene (HDPE) was studied. An innovative milling apparatus, viz. an inlaid pan-mill, was used. Melt indexer, capillary rheometer, Haake Rheocord 90 single-screw extruder and Brabender rheometer were used to evaluate the rheological properties of HDPE. HDPE with higher initial molecular weight and larger particle size was easier to degrade under pan-milling stress, as indicated by the melt index. Pressure oscillation in capillary flow occurred at significantly higher shear stress and shear rate for milled HDPE than for unmilled HDPE. The apparent shear viscosity of HDPE decreased with increasing times of milling. After milling, the flow activation energy decreased and thus the sensitivity of viscosity to temperature was reduced. Die pressure and torque during single screw extrusion were reduced significantly after milling. Plasticizing time as measured in a Brabander mixer decreased markedly with increasing milling times.

关键词： high density polyethylene rheological properties pan-milling

MAPPING THE DAMAGED ZONE AROUND THE CRACK TIP IN high density polyethylene WITH SYNCHROTRON MICROFOCUS SMALL ANGLE X-RAY SCATTERING TECHNIQUE

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Chinese Journal of Polymer Science 2010年第2期28卷 165-170页

作者： Hans-Friedrich Enderle Dieter Lilge Stephan V.Roth Rainer Gehrke Jens Rieger 门永锋 Basell Polyolefine GmbH R&D65926 FrankfurtGermany HASYLAB am DESY Notkestr.8522607 HamburgGermany BASF SE Polymer Research67056 LudwigshafenGermany State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of Sciences

The structural changes around a crack tip in a high density polyethylene were investigated by means of scanning synchrotron microfocus small-angle X-ray scattering technique. The scattering data confirm the process of craze structure development near a crack tip based on the evolution of voids. In addition, it was found that the main stress in the plastic zone near a crack tip exhibited a gradient distribution with respect to its strength and direction. The whole damaged area showed a strain distribution indicating a flow behavior toward the crack tip.

关键词： high density polyethylene Microfocus SAXS Crack tip Voids.

PREPARATION OF high density polyethylene/polyethylene-BLOCK-POLY(ETHYLENE GLYCOL)COPOLYMER BLEND POROUS MEMBRANES VIA THERMALLY INDUCED PHASE SEPARATION PROCESS AND THEIR PROPERTIES

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Chinese Journal of Polymer Science 2010年第3期28卷 337-346页

作者：朱宝库 Department of Polymer Science and Engineering Key Laboratory of Macromolecule Synthesis and Functionalization(Ministry of Education)Zhejiang University

high density polyethylene （HDPE）/polyethylene-block-poly（ethylene glycol）（PE-b-PEG） blend porous membranes were prepared via thermally induced phase separation （TIPS） process using diphenyl ether （DPE） as diluent. The phase diagrams of HDPE/PE-b-PEG/DPE systems were determined by optical microscopy and differential scanning calorimetry （DSC）. By varying the content of PE-b-PEG, the effects of PE-b-PEG copolymer on morphology and crystalline structure of membranes were studied by scanning electron microscopy （SEM） and wide angle X-ray diffraction （WAXD）. The chemical compositions of whole membranes and surface layers were characterized by elementary analysis, Fourier transform infrared spectroscopy-attenuated total reflection （FTIR-ATR） and X-ray photoelectron spectroscopy （XPS）. Water contact angle, static protein adsorption and water flux experiments were used to evaluate the hydrophilicity, antifouling and water permeation properties of the membranes. It was found that the addition of PE-b-PEG increased the pore size of the obtained blend membranes. In the investigated range of PE-b-PEG content, the PEG blocks could not aggregate into obviously separated domains in membrane matrix. More importantly, PE-b-PEG could not only be retained stably in the membrane matrix during membrane formation, but also enrich at the membrane surface layer. Such stability and surface enrichment of PE-b-PEG endowed the blend membranes with improved hydrophilicity, protein absorption resistance and water permeation properties, which would be substantially beneficial to HDPE membranes for water treatment application.

关键词： high density polyethylene polyethylene-block-poly(ethylene glycol) copolymer Blend porous membrane Thermally induced phase separation.

Study on the Basic Mechanical Behaviors of high density polyethylene Electrofusion Welded Joints at Different Temperature

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Journal of Materials Science & Technology 2003年第6期19卷 603-606页

作者： Lixing HUO, Fangjuan QI, Yufeng ZHANG, Hongyang JING and Xinqi YANGSchool of Materials Science and Engineering, Tianjin University, Tianjin 300072, China Sch. of Mat. Sci. and Eng. Tianjin Univ. Tianjin 300072 China

The basic mechanical behaviors of high density polyethylene electrofusion welded joint at different temperatures were studied by using differently designed specimens in this paper. The results show that the strength of weld bonding plane is higher than that of the pipe and socket materials at room temperature. In order to get the shear strength of electrofusion welded joint, the effective bond lengths were reduced by cutting artificial groove through the socket. The effective bonding length of welded joint to get the shear strength is decreased with decreasing testing temperature. The shear strength and the sensibility to sharp notch of HDPE material increased with decreasing temperature.

关键词： Basic mechanical behaviors high density polyethylene Electrofusion welded joint

Structure,Characterization and Thermal Properties of the Form-Stable Paraffin/high-density polyethylene/Expanded Graphite/Epoxy Resin Composite PCMs for Thermal Energy Storage

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Journal of Thermal Science 2023年第6期32卷 2104-2114页

作者： MOMBEKI PEA Hamir Johan AN Zhoujian DU Xiaoze SHI Tianlu ZHANG Dong School of Energy and Power Engineering Lanzhou University of TechnologyLanzhou730050China Key Laboratory of Complementary Energy System of Biomass and Solar Energy Gansu ProvinceLanzhou730050China

The form-stable paraffin/high-density polyethylene/expanded graphite/epoxy resin composite phase change materials(CPCMs),exhibiting suitable thermal properties,including low melting temperature,high conductivity and high phase change enthalpy,was developed in this ***,paraffin(PA)was utilized as a core ***-density polyethylene(HDPE)was utilized for the shape stabilization and preventing the PCMs *** graphite(EG)was used to increase its thermal conductivity and act also in the porous supporting *** resin(ER)was used to provide flexible encapsulated scaffold morphology and keep a highly tight network structure of the ***,the physical architecture,the chemical architecture and thermal behavior properties of specimens were investigated by using the spectroscopy and calorimetry *** scanning electron microscope(SEM),X-ray diffraction(XRD)and fourier transform infrared spectrometer FTIR tests have shown good uniformity structure and good compatibility of *** addition,the thermal conductivity tests revealed that the thermal conductivity of PA,initially 0.31 W/(m·K)improved up to 1.9 times by adding the 6 wt%mass fraction of EG in composite ***,the differential scanning calorimeter(DSC)measurements indicated that PA melting enthalpy,initially 231 J/g decreased up to 125 J/g with the increase of the amount of HDPE which was due to the limitation caused by the atomic network constructed by the base *** thermogravimetric analyzer(TGA)and leakage-proof revealed the enhancement of the degradation of PA with the raise of amount of the HDPE into the ***,the proposed form-stable CPCMs are a great candidate for the thermal regulation and thermal energy storage employment.

关键词： form-stable CPCMs paraffin expanded graphite high density polyethylene epoxy resin thermal energy storage

MECHANICAL PROPERTIES OF OZONIZED HDPE FILLED WITH SERICITE-TRIDYMITE-CRISTOBALITE

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Chinese Journal of Polymer Science 2005年第1期23卷 17-21页

作者： MianZhou YiFu WenXu XiXu TheStateKeyLabofPolymerMaterialsEngineeringofChina PolymerResearchInstituteofSichuanUniversityChengdu610065China

The mechanical properties of ozonized high density polyethylene(HDPE)blended with sericite-tridymite-cristobalite(STC)were studied in this *** experimental results show that some oxygen containing polar groups areintroduced on the molecular chain of HDPE through ozonization,the compatibility between HDPE and STC is thusimproved,the mechanical properties of the blend are markedly *** with untreated HDPE/STC(60/40)blend,the yield strength and notched impact strength of ozonized HDPE/STC(60/40)blend are increased from 27.0 MPa to29.5 MPa and from 2.8 kJ/m^2 to 13.3 kJ/m^2,respectively,the notched impact strength is close to that of HDPE(13.6 kJ/m^2),the yield strength is in excess of 3.9 MPa of that of *** yield strength and notched impact strength will be furtherincreased to 30.7 MPa and 32.4 kJ/m^2 in case the ozonized HDPE is blended with STC pretreated with silane coupling agent.

关键词： Ozonization high density polyethylene Sericite-tridymite-cristobalite.

A STUDY ON MECHANICAL PROPERTIES OF γ-RAY IRRADIATED HDPE FILLED WITH SERICITE-TRIDYMITE-CRISTOBALITE

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Chinese Journal of Polymer Science 1998年第4期16卷 339-344页

作者：徐闻肖望东徐僖 The State Key Lab. of Polymer Materials Engineering Polymer Research Institute of Chengdu University of Science and Technology Chengdu 610065 China

The effect of γ-ray irradiation on the mechanical properties of high densitypolyethylene(HDPE) filled with sericite-tridymite-cristobalite(STC) was studied. The ex-perimental results show that γ-ray irradiation can improve the affinity between HDPE andSTC, and the dispersion of STC in HDPE matrix. Compared with HDPE/STC (80/20)blend, the yield stress and impact strength of irradiated HDPE (10kGy)/STC (80/20) blendare increased from 22.8 MPa and 70J/m to 28.5 MPa and 144J/m. The yield stress andimpact strength of HDPE/irradiated HDPE/STC (48/32/20) are 27.8MPa and 210J/m,respectively.

关键词： γ-Ray irradiation high density polyethylene Sericite-tridymite-cristobalite

Gas phase ethylene polymerization over SiO_(2)-supported organosilyl chromate UCC S-2 catalyst using a high-speed stirred-autoclave reactor

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Frontiers of Chemical Science and Engineering 2011年第1期5卷 89-95页

作者： Liuzhong LI Aiyou HAO Ruihua CHENG Boping LIU School of Chemistry and Chemical Engineering Shandong UniversityJinan 250100China State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China Research Institute of Qilu Branch Co. SINOPECZibo 255400China

Although an important industrial catalyst for producing high density polyethylene,the SiO_(2)-supported organosilyl chromate UCC S-2 catalyst has not been fully investigated compared with the SiO_(2)-supported oxo chromium Phillips *** this work,gas phase ethylene polymerization by S-2 catalysts(Cat-1,Cat-2,and Cat-3)was carried out in a high-speed stirredautoclave *** effects of temperature,time,and pressure on kinetics,activity,and product properties were *** kinetics were typical built-up types with slow *** to the simple physical mixtures of Cat-1 and Cat-2,Cat-3 showed higher activity and its product had a broader molecular weight distribution,indicating new active species induced during blending of Cat-1 and Cat-2 in *** innovation by a simple catalyst technology created a new application to meet market demands.

关键词： UCC S-2 catalyst Al-alkyl co-catalyst gasphase ethylene polymerization high density polyethylene

The Influence of Unidirectional Pressure on Electrical Conductivity of Carbon Black Filled polyethylene

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Journal of Wuhan University of Technology(Materials Science) 2006年第3期21卷 76-78页

作者：王可张国 Key Laboratory of Automobile Materials of Education Jilin UniversityChangchun 130023College of Materials Science and Engineering Jilin University Changchun 130023

high density polyethylene filled with condutuctive carbon black was prepared by conventional meltmixing method. The effect of unidirectional pressure on the conductivity was studied. Wide angle X-ray diffraction （ WAXD ） was used to slum： the influence of pressure on the aggregate structure of the polymer filled with carbon black （CB） fillers. A model on the basis of the formation and destruction of conductive networks was proposed to explain the change in the conductivity with the application of pressure.

关键词： high density polyethylene carbon black electrical conductivity pressure sensors