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Rheological Behavior of the Melts for Polyethylene-based Montmorillonite Nanocomposites

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Chemical Research in Chinese Universities 2006年第5期22卷 651-657页

作者： YANG Hong-mei ZHENG Qiang DU Miao Department of Polymer Science and Engineering Zhejiang University Hangzhou 310027 P. R. China National Engineering Research Center for compounding and Modification of Polymer Materials Guiyang 550025 P. R. China

The viscoelastic properties of melts of nanocomposites with partially exfoliated structures, which were composed of low-density polyethylene （LDPE）, ethylene vinyl acetate copolymer （EVA）, and montmofillonite and modified by cetyltrimethyl ammonium bromide and octadecyltrimethyl ammonium bromide, were studied. The results obtained through measurements of the dynamic storage modulus G′, the dynamic loss modulus G″, and the transiem stress relaxation modulus G（t） of the composites, reveal that the viscoelastic properties of the composites strongly depend on the amount of montmorillonite that is exfoliated into the composites. With the increase in montmoriUonite content, the composites show an obvious property of pseudo solid-like materials within the region of lower frequencies （ω）. The montmorillonite layers are aligned along the stress direction, and the dependence of dynamic modulus on ω, appears quite different for the composites before and after being exposed to a large amplitude oscillatory shears.

关键词： Rheological behavior Nanocomposite Polyethylene Montmorillonite

Morphology and Mechanical Properties of Nylon 6/PBT Blends Compatibilized with Styrene/Maleic Anhydride Copolymer

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Chemical Research in Chinese Universities 2007年第6期23卷 726-732页

作者： QIN Shu-hao YU Jie ZHENG Qiang HE Min ZHU Hong Department of Polymer Science and Engineering Zhejiang University Hangzhou 310027 P. R. China National Engineering Research Center for compounding and Modification of Polymeric Materials Guiyang 550025 P. R. China

The mechanical properties and dynamic mechanical properties of blends composed of Nylon 6 and poly （ butylenes terephthalate）（PBT）, with styrene/maleic anhydride（SMA） as compatibilizer, were studied. The observation on the morphologies of the etched surfaces of the cryogenically fractured specimens via scanning electron microscopy（SEM） demonstrated that in the compatibilized Nylon 6/PBT blends, there exists a finer and more uniform dispersion induced by the in-situ interfacial chemical reactions during the preparation than that in the corresponding uncompatibilized blends. On the other hand, the overall mechanical properties of the compatibilized blends could be remarkably im- proved compared with those of the uncompatibilized ones. Moreover, increasing the amount of the compatibilizer SMA leads to a more efficient dispersion of the PBT phase in Nylon 6/PBT blends. Furthermore, there exists an optimum level of SMA added to achieve the maximum mechanical properties. As far as the mechanism of this reactive compatibilization is concerned, the enhanced interfacial adhesion is necessary to obtain improved dispersion, stable phase morphology, and better mechanical properties.

关键词： Nylon-6 PBT Morphology Dynamic mechanical property

Fully Bio-Based Composites of Poly(Lactic Acid)Reinforced with Cellulose-Graft-Poly-(ε-Caprolactone)Copolymers

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Journal of Renewable Materials 2023年第3期11卷 1137-1152页

作者： Chengtao Gao Yang Wu Haibo Xie College of Materials and Metallurgy Guizhou UniversityGuiyangChina National Engineering Research Center for compounding and Modification of Polymer Materials(Guizhou Material Industrial Technology Institute) GuiyangChina College of Materials Science&Engineering University of NanchangNanchangChina

Due to the increasing demand for modified polylactide(PLA)meeting“double green”criteria,the research on sustainable plasticizers for PLA has attracted broad *** study reported an open-ring polymerization method to fabricate cellulose(MCC)-g-PCL(poly(ε-caprolactone))copolymers with a fully sustainable and biodegradable ***-g-PCL copolymers were synthesized,characterized,and used as green plasticizers for the PLA *** results indicated that the MCC-g-PCL derivatives play an important role in the compatibility,crystallization,and toughening of the PLA/MCC-g-PCL *** mechanical properties of the fully bio-based PLA/MCC-g-PCL composites were optimized by adding 15 wt%MCC-g-PCL,that is,the elongation at break was 22.6%(~376%higher than that of neat PLA),the tensile strength was 47.3 MPa(comparable to that of neat PLA),and the impact strength was 26 J/m(~130%higher than that of neat PLA).DSC results indicated that MCC-g-PCL reduced the Tg of the PLA *** the addition amount was 15 wt%,the Tg of the blend was 58.4°*** with MCC,MCC-g-PCL polyester plasticizer has better thermal stability,T5%(°C)can still be maintained above 300°*** rheological results showed that MCC-g-PCL acted as a plasticizer,the introduction of PCL flexible chain increased the mobility of PLA molecular chain,and decreased the complex viscosity,storage modulus and loss modulus of PLA *** MCC-g-PCL derivatives,as a new green plastic additive,have shown an interesting prospect to prepare fully bio-based composites.

关键词： Green plasticizers PLA cellulose(MCC)-g-PCL fully bio-based composites

Synthesis and Characterization of Polystyrene/Nanosilica Organic-Inorganic Hybrid

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Chemical Research in Chinese Universities 2006年第6期22卷 797-802页

作者： YUAN Wang-zhang PENG Mao YU Qiu-ming TANG BEN-zhong ZHENG Qiang Department of Polymer Science and Engineering Zhejiang University Hangzhou 310027 P. R. China National Engineering Research Center for compounding and Modification of Polymer Materials Guiyang 550025 P. R. China Department of Chemistry Hong Kong University of Science and Technology Kowloon Hong Kong P. R. China

A polystyrene（PS）/nanosilica organic-inorganic hybrid material was prepared from styrene monomer and commercial aqueous silica sol containing large amounts of Si-OH by means of emulsion polymerization. The nanosilica sol was modified by the addition of the reactive coupling agent methacrylexy propyltrimethoxysilane （ MPS）, and the resulting latex particles were protected by surfactants such as sodium dodecyl sulphonate（ SDS）, hydroxypropyl methyl cellulose （ HMPC）, and poly （vinylpyrrolidone）（PVP）. The effects of the type of surfactant, the amount of surfactant, and the coupling agent on the shape and stability of the resulting latex particles were investigated. The TEM observation indicates that among SDS, HMPC, and PVP, SDS is the best surfactant. When the content of SDS is 0. 5% and the amount of MPS is 7% in the system, the latex with obvious core-shell structure could be obtained. The average diameters of the monodispersed particles range from 182 to 278 nm, and the average number of silica beads for each composite are 1325 and 4409, respectively. The FrIR analysis shows that PS was chemically linked to silica through MPS. The thermal gravimetric analysis shows that when there is a higher silica content, the hybrid composites have a better heat resistance.

关键词： Commercial aqueous silica sol Organic-inorganic hybrid particle Core-shell latex 1005-9040 (2006) -06-797-06

THE EFFECT OF BLENDING SEQUENCE ON PHASE MORP HOLOGY OF NYLON 6/ABS/SMA BLENDS

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THE EFFECT OF BLENDING SEQUENCE ON PHASE MORP HOLOGY OF NYLO...

High EMI shielding effectiveness and superhydrophobic properties based on step-wise asymmetric structure constructed by one-step method

作者：秦舒浩于杰 Department of Polymer Science and Engineering Zhejiang University Hangzhou 310027China National Engineering Research Center for compounding and Modification of Polymeric Materials Guiyang 550025China National Engineering Research Center for compounding and Modification of Polymeric Materials Guiyang 550025 China

The preparation process-dependent phase morphology of blends composed of nylon 6 and acrylonitrile-butadiene-styrene(ABS) over a composition range of 30 70 wt%using a styrene-maleic anhydride (SMA) copolymer as the compatibilizing agent with a constant content(5phr) was *** results of the scanning electron microscope(SEM) observation revealed that compared with the binary blends of nylon 6 and ABS,the existence of SMA caused a composition shift of phase inversion to a higher weight fraction of nylon 6 when ABS was blended with the preblended nylon 6/SMA blend,while the co-continuous structures could be observed over a considerably narrower composition range when nylon 6 was blended with the pre-blended ABS/SMA *** examination through dynamic mechanical analysis(DMA) tests confirmed the results obtained with *** is found that near the phase inversion region a remarkable change in the dynamic storage modulus(G) and the loss tangent(tanδ) ***,the influence of blending sequence on the size of dispersed particles has been probed for uncompatibilized and compatibilized blends of nylon 6 and ABS over a wide range of compositions below or beyond the phase inversion *** the blends of ABS dispersed in a nylon 6 matrix,little discernible effects of blending sequence on particle size could be ***, there exists a significant difference in morphologies of the blends prepared by nylon 6 particles dispersing in a ABS matrix in cases of different blending sequences *** possible factors responsible for the above asymmetric behaviors have been proposed.

关键词： Nylon 6 ABS Morphology Blending sequence Dynamic mechanical properties

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Nano Research 2023年第7期16卷 10483-10492页

作者： Kang Yan Changmei Wu Lan Xie Lingjun Zeng Yi Jiang Zhiqiang Jiang Guojun Chang Bai Xue Qiang Zheng Department of Polymer Materials and Engineering College of Materials and MetallurgyGuizhou UniversityGuiyang 550025China State Key Laboratory of Public Big Data Guizhou UniversityGuiyang 550025China National Engineering Research Center for compounding and Modification of Polymer Materials Guiyang 550014China National and Local Joint Engineering Research Center for Functional Polymer Membrane Materials and Membrane Processes Guiyang 550014China Department of Polymer Science and Engineering Zhejiang UniversityHangzhou 310027China

It is of significance to prepare biodegradable electromagnetic interference(EMI)shielding materials with high EMI shielding effectiveness(SE)in order to solve electromagnetic and environmental pollution *** this paper,environmentally friendly EMI shielding silver nanowires(AgNWs)/poly(L-lactic acid)(PLLA)/poly(D-lactic acid)(PDLA)/ferroferric oxide(Fe_(3)O_(4))composites with step-wise asymmetric structures were prepared by a facile one-step non-solvent-induced phase separation *** conductive AgNW network was constructed at a low mass fraction of 5 wt.%on the surface of stereo-complexed crystalline poly(lactic acid)(SC-PLA)film(1.08×10^(4) S/m).Moreover,magnetic Fe_(3)O_(4)is mainly distributed in the skeleton of porous SC-PLA *** to the synergistic effect of AgNWs and Fe_(3)O_(4),the EMI SE of SC-PLA films reaches up to 50.3 ***,SC-PLA film modified with triethoxy-1H,1H,2H,2H-tridecafluoro-n-octylsilane(TTO)demonstrates an outstanding water contact angle of about 150.2°compared with the pure PLLA film(134.7°),stemming from the synergistic effect of denser SC-PLA nano-protrusions and low-surface-energy ***,we successfully fabricated the high EMI shielding SC-PLA film with wonderful superhydrophobicity,which extends the application performance and service life of portable electronics in moist environments.

关键词： phase separation electromagnetic interference super-hydrophobicity Ag nanowire step-wise asymmetric structure

Hierarchical Ni-plated melamine sponge and MXene film synergistically supported phase change materials towards integrated shape stability,thermal management and electromagnetic interference shielding

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Journal of Materials Science & Technology 2023年第1期132卷 132-143页

作者： Ziling Cheng Guojun Chang Bai Xue Lan Xie Qiang Zheng State Key Laboratory of Public Big Data Guizhou UniversityGuiyang 550025China Department of Polymer Materials and Engineering College of Materials and MetallurgyGuizhou UniversityGuiyang 550025China National Engineering Research Center for compounding and Modification of Polymer Materials National and Local Joint Engineering Research Center for Functional Polymer Membrane Materials and Membrane ProcessesGuiyang 550014China College of Polymer Science and Engineering Zhejiang UniversityHangzhou 310000China

Along with the integrated and miniaturized development of advanced electronic devices,phase change materials(PCMs)simultaneously with efficient thermal management and high electromag-netic interference(EMI)shielding effectiveness(SE)are ungently ***,the shape-stabilized MXene/Ni-platted melamine sponge/Regenerated cellulose/Graphene nanoplate/Polyethylene glycol(MX/Ni@MS/RCG/PEG)composite PCMs comprising hierarchical Ni@MS/RCG and MXene film were fabricated via a facile encapsulation *** Ni@MS/RCG hybrid aerogel was prepared by electroless plating and sol-gel methods,and MXene film was obtained using vacuum-assisted filtra-tion *** synergistic effect of conductive Ni@MS/RCG networks and tight MXene film endows MX/Ni@MS/RCG/PEG composite PCMs with good shape stability,high cyclic reliability,large latent heat of phase change(154.3 J g^(–1)),excellent thermal conductivity(TC,0.47 W m^(–1)K^(–1))and favorable EMI shield-ing performance(32.7 dB).The TC of acceptable 0.47 W m^(–1)K^(–1)is observed for MX/Ni@MS/RCG-5/PEG at a rather low GNP content of merely 0.39 wt%.In addition,the temperature variation of MX/Ni@MS/RCG-5/PEG is a lot faster than that of pure PEG in the heating/cooling process,revealing the remarkable energy storage and release efficiency for the composite *** investigation has taken an important step to-wards shape-stabilized composite PCMs with both effective thermal management and high EMI SE for promising applications in electronic packaging and advanced energy.

关键词： Phase change material Thermal management Electromagnetic interference shielding Shape stability Encapsulation

Directional Electromagnetic Interference Shielding Based on Step-Wise Asymmetric Conductive Networks

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Nano-Micro Letters 2022年第1期14卷 262-277页

作者： Bai Xue Yi Li Ziling Cheng Shengdu Yang Lan Xie Shuhao Qin Qiang Zheng Department of Polymer Materials and Engineering College of Materials and MetallurgyGuizhou UniversityGuiyang 550025People’s Republic of China National Engineering Research Center for compounding and Modification of Polymer Materials National and Local Joint Engineering Research Center for Functional Polymer Membrane Materials and Membrane ProcessesGuiyang 550014People’s Republic of China College of Polymer Science and Engineering Zhejiang UniversityHangzhou 310027People’s Republic of China College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024People’s Republic of China

Some precision electronics such as signal transmitters need to not only emit effective signal but also be protected from the external electromagnetic(EM)***,directional electromagnetic interference(EMI)shielding materials(i.e.,when the EM wave is incident from different sides of the sample,the EMI shielding effectiveness(SE)is rather different)are strongly required;unfortunately,no comprehensive literature report is available on this research ***,Nicoated melamine foams(Ni@MF)were obtained by a facile electroless plating process,and multiwalled carbon nanotube(CNT)papers were prepared via a simple vacuum-assisted self-assembly ***,step-wise asymmetric poly(butylene adipate-co-terephthalate)(PBAT)composites consisting of loose Ni@MF layer and compact CNT layer were successfully fabricated via a facile solution encapsulation *** step-wise asymmetric structures and electrical conductivity endow the Ni@MF/CNT/PBAT composites with unprecedented directional EMI shielding *** the EM wave is incident from Ni@MF layer or CNT layer,Ni@MF-5/CNT-75/PBAT exhibits the total EMI SE(SET)of 38.3 and 29.5 dB,respectively,which illustrates theΔSET of 8.8 *** work opens a new research window for directional EMI shielding composites with step-wise asymmetric structures,which has promising applications in portable electronics and next-generation communication technologies.

关键词： Solution encapsulation Step-wise asymmetry Directional electromagnetic interference shielding Electrical conductivity Vacuum-assisted self-assembly

Biochar affects methylmercury production and bioaccumulation in paddy soils: Insights from soil-derived dissolved organic matter

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Journal of Environmental Sciences 2022年第9期34卷 68-77页

作者： Siqi Zhang Mingxing Wang Jiang Liu Shanyi Tian Xueling Yang Guangquan Xiao Guomin Xu Tao Jiang Dingyong Wang Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin Department of Environmental Sciences and EngineeringCollege of Resources and EnvironmentSouthwest UniversityChongqing 400716China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550002China Soil Ecology Laboratory College of Resources and Environmental SciencesNanjing Agricultural UniversityNanjing 210095China National Engineering Research Center for compounding and Modification of Polymer Materials Guiyang 550014China Guizhou Material Industrial Technology Institute Guiyang 550014China Institute of Environment and Health Jianghan UniversityWuhan 430056China

Biochar has been used increasingly as a soil additive to control mercury(Hg) pollution in paddy rice fields. As the most active component of soil organic matter, soil dissolved organic matter(DOM) plays a vital role in the environmental fate of contaminants. However, there are very few studies to determine the impact of biochar on the Hg cycle in rice paddies using insights from DOM. This study used original and modified biochar to investigate their effect on DOM dynamics and their potential impact on methylmercury(MeHg) production and bioaccumulation in rice plants. Porewater DOM was collected to analyze the variations in soil-derived DOM in paddy soils. The results showed that the addition of biochar, whether in original or modified form, significantly reduced the bioaccumulation of MeHg in rice plants, especially in hulls and grains( p < 0.05). However, MeHg production in soils was only inhibited by the modified biochar. Biochar addition induced a significant increase in DOM’s aromaticity and molecular weight( p < 0.05), which decreased Hg bioavailability. Furthermore, enhanced microbial activity was also observed in DOM( p < 0.05), further increasing MeHg production in the soil. Thus, the effect of biochar on the fate of Hg cycle involves competition between the two different roles of DOM. This study identified a specific mechanism by which biochar affects Hg behavior in rice paddy soil and contributes to understanding the more general influence of biochar in agriculture and contaminant remediation.

关键词： Dissolved organic matter Mercury Methylmercury Biochar Rice