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Phase Structure and Crystallization Behavior of Polyethylene in Its Blends with cis-1,4-Butadiene Rubber

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Chinese Journal of Polymer Science 2015年第3期33卷 386-394页

作者： Hong Yao Jun-teng liu li-qun zhang 闫寿科 Beijing Key Laboratory of Membrane Science & State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology

Phase structure and crystallization behavior of polyethylene （PE） in its blends with cis-1,4-butadiene rubber （BR） at different blend ratios and sample preparation conditions were studied. The PE is finely dispersed in the BR matrix. For samples hot pressed at 145 ℃, circular PE microdomains with randomly oriented PE lamellar aggregates were produced. The domain size and number increase with increasing PE content. When the PE content is over 10 wt%, most of the PE domains impinged each other. The separated PE domains are connected by PE stripes with parallel arranged lamellar aggregates. For samples hot pressed at 140 ℃, elongated PE microdomains with oriented PE lamellar aggregates were obtained due to the shear flow. The crystallization of PE in the blends depends on the phase structure. Confined crystallization of PE occurs in small microdomains at relatively low temperature. With the increase of domain size, the crystallization ability of PE increases while the confined crystallization decreases.

关键词： Polyethylene cis-1,4-Butadiene rubber Blend Crystallization Morphology.

Bubble-templated Construction of Three-dimensional Ceramic Network for Enhanced Thermal Conductivity of Silicone Rubber Composites

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Chinese Journal of Polymer Science 2021年第7期39卷 789-795页

作者： Shou-Jun li Jing-Chao li Pei-ZhiJi Wen-Feng zhang Yong-Lai Lu li-qun zhang State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing 100029China Beijing Key Laboratory of Wood Science and Engineering&MOE Key Laboratory of Wooden Material Science and Application Beijing Forestry UniversityBeijing W0083China Key Laboratory of Carbon Fiber and Functional Polymers Ministry of EducationBeijing University of Chemical TechnologyBeijing 100029China Engineering Research Center of Elastomer Materials Energy Conservation and Resources Ministry of EducationBeijing University of Chemical TechnologyBeijing 100029China

With the continuous development of the electronics industry,the energy density of modern electronic devices increases constantly,thus releasing a lot of heat during *** electronic devices take higher and higher request to the thermal interface *** high thermal conductivity needs to establish an interconnecting thermal conductivity network in the *** this purpose,the suspension of Al203 and curdlan was first foamed to construct a bubble-templated continuous ceramic *** to the rapid gelation property of curdlan,we can easily remove moisture by hot air ***,the high thermally conductive composites are prepared by vacuum impregnation of silicone *** result showed that composites prepared by our method have higher thermal conductivity than the samples obtained by traditional *** thermal conductivity of the prepared composite material reached 1.253 W·m^(-1)·K·^-(1)when the alumina content was 69.6 wt%.This facile method is expected to be applied to the preparation of high-performance thermal interface materials.

关键词： Thermally conductive network Alumina Curdlan Thermal conductivity

Morphologies and Mechanical Properties of Cis-1,4-butadiene Rubber/Polyethylene Blends

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Chinese Journal of Polymer Science 2016年第7期34卷 820-829页

作者： Hong Yao Jia-li Niu Jie zhang Nan-ying Ning Xiao-qiu Yang 田明 Xiao-li Sun li-qun zhang 闫寿科 State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Beijing 100029 China Beijing National Laboratory for Molecular Sciences Department of Polymer Science and Engineering & the Key Laboratory of Polymer Chemistry and Physics of Ministry of Education College of Chemistry and Molecular Engineering Peking University Beijing 100871 China Basic Research Service MOST Beijing 100862 China

The mechanical properties and phase morphologies of cis-1,4-butadiene rubber（BR） blended with polyethylene（PE） at different blend ratios were studied. The tensile test results show that the PE exhibits excellent reinforcing capabilities towards BR. Blending BR with PE results in a remarkable enhancement of tensile strength, modulus and the elongation at break simultaneously. An increment of tensile strength from 1.11 MPa to 16.26 MPa was achieved by incorporation of 40 wt% PE in the blends. The modulus and elongation at break of 40/60 PE/BR blends are also about 5 times higher than those of the pure BR treated under exactly the same conditions. The tear test indicates that the tear strength also increases with the increase of PE content. It reaches 58.38 MPa for the 40/60 PE/BR blend, which is approximately 10 times higher than that of the pure BR. Morphological study demonstrates that the PE forms elongated microdomains finely dispersed in the BR matrix when its content is over 30 wt%, which corresponds to the remarkably enhanced mechanical *** to the results, reinforcement mechanism of PE toward BR dependent on the microstructure has been discussed and two different mechanisms have been proposed.

关键词： Polyethylene Cis-1 4-butadiene rubber Blend Mechanical property Morphology

Tuning the Electrically Conductive Network of Grafted Nanoparticles in Polymer Nanocomposites by the Shear Field

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Chinese Journal of Polymer Science 2020年第12期38卷 1426-1434页

作者： Yan-Long Luo Xiao Hui Duan Bin li Xin-ling Chen Yang Yang Gao li-qun zhang Cllege of Science Nanjing Forestry UniversityNanjing 210037 China KeyLaboratoryof Bejing Ciy on Preparation and Pocessing of Novel Polmer Materials Bejing University ofChemical TechnologyBejing 100029China State Key Laboratory of Organic-lnorganic Composites Bejing Universityof Chemical Technology Bejing 10029China School of Chemical Engneering and Technology.Sun Yat sen University Zhuhai 519082 China

Contolling the formation of the conductive network in the polymer nanocomposites(PNCs)is very meaningful to enhance their electrical *** this work,we investigated the effect of grafted nanoparticles(NPs)on the conductive probability of PNCs in the quiescent state as well as under the shear field via a coarse grained molecular dynamics *** is found that the smallest percolation threshold is realized at the moderate grafting density,the moderate length of grafted chains or the moderate interaction between grafted chains and free *** to it,the dispersion state of NPs varies from the contact aggregation to the uniform *** analyzing the connection mode among NPs,the probabilty of NPs which connect three other ones reaches the maximum value at their moderate dispersion state which is responsible for the optimal conductive *** addition,the main cluster size is characterized to better understand the conductive network which is consistent with the percolation *** is interesting to find that the percolation threshold is smaller under the shear field than under the quiescent *** shear field induces more NPs which connect three other *** benefits the formation of the new conductive ***,the anisotropy of the conductive probability is reduced with increasing the grafting *** summary,this work provides a clear picture on how the conductive network of grafted NPs evolves under the shear field.

关键词： Conductive network Grafted nanoparticles Molecular dynamics simulation

Theoretical Interpretation of Conformation Variations of Polydimethylsiloxane Induced by Nanoparticles

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Chinese Journal of Polymer Science 2018年第4期36卷 505-513页

作者： Zhao-Yang Wei Nan-Ying Ning Ming Tian li-qun zhang Jian-Guo Mi State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical Technology Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical Technology

There has been controversy as to whether the addition of nanoparticles to a polymer melt causes perturbed chain structure of polymers. In this work, the chain conformations of polydimethylsiloxane（PDMS） with addition of polyhedral oligomeric silsesquioxane（POSS） nanoparticles have been studied using a classical density functional approach. Under the strong interactions of POSS-PDMS, the radius of gyration of PDMS in the nanocomposites can either increase or decline depending on particle loading. After adding nanoparticles with larger size or weaker interactions, both the increasing and the declining amplitudes can be largely suppressed. The results provide a deep understanding of chain conformation in polymer nanocomposites.

关键词： Chain conformation Radius of gyration Polymer nanocomposites Density functional theory

Dispersion and Filler Network Structure of Fibrillar Silicates in Elastomers

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Chinese Journal of Polymer Science 2016年第7期34卷 858-872页

作者： Zhao li Hai-bin Sun Cong-yi li Yong-lai Lu Wang Qiao 宁南英 li-qun zhang 田明 Aeolus Tyre Co. Ltd State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical Technology Petro China Sichuan Petrochemical Co. Ltd Office of Scientific Research and Development Beijing University of Chemical Technology

The dispersion and filler network of fibrillar silicate（FS） in elastomers were studied. The results showed that a good dispersion of FS in matrix during mechanical blending in unvulcanized composites contributed to a strong FS filler network, different from that of traditional reinforcing fillers. Meanwhile, the filler re-aggregation during vulcanization caused by the overlapping and intertwining of FS further strengthened the filler network. The factors including Mooney viscosity and molecular polarity of elastomer, type and amount of silane coupling agents used for filler modification, that may influence the filler network, were studied. Our study helps us to understand the mechanism for the formation of filler network of FS in elastomers and provides guidance for the preparation of high performance FS/elastomer composites.

关键词： Fibrillar silicates Dispersion Filler network Elastomers

Effect of the Nanoparticle Functionalization on the Cavitation and Crazing Process in the Polymer Nanocomposites

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Chinese Journal of Polymer Science 2021年第2期39卷 249-257,I0008页

作者： Yan-Long Luo Tian-Tian li Bin li Xian-ling Chen Zhen-Yang Luo Yang-Yang Gao li-qun zhang College of Science Nanjing Forestry UniversityNanjing 210037China State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing 100029China Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials Beijing University of Chemical TechnologyBeijing 100029China School of Chemical Engineering and Technology Sun Yat-sen UniversityZhuhai 519082China

The nanoparticle(NP) functionalization is an effective method for enhancing their compatibility with polymer which can influence the fracture property of the polymer nanocomposites(PNCs). This work aims to further understand the cavitation and crazing process, hoping to uncover the fracture mechanism on the molecular level. By adopting a coarse-grained molecular dynamics simulation, the fracture energy of PNCs first increases and then decreases with increasing the NP functionalization degree α while it shows a continuous increase with increasing the interaction εpA between polymer and modified beads. The bond orientation degree is first characterized which is referred to as the elongation. Meanwhile, the stress by polymer chains is gradually reduced with increasing the α or the εpA while that by NPs is ***, the percentage of stress by polymer chains first increases and then decreases with increasing the strain while that by NPs shows a contrast trend. Moreover, the number of voids is quantified which first increases and then decreases with increasing the strain which reflects their nucleation and coalescence process. The voids prefer to generate from the polymer-NP interface to the polymer matrix with increasing α o r ε*** a result, the number of voids first increases and then decreases with increasing α while it continuously declines with the εpA. In summary, our work provides a clear understanding on how the NP functionalization influences the cavitation and crazing process during the fracture process.

关键词： Nanoparticle functionalization Cavitation and crazing Polymer nanocomposites Molecular dynamics simulation

Excellent Compatibilization Effect of a Dual Reactive Compatibilizer on the Immiscible MVQ/PP Blends

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Chinese Journal of Polymer Science 2023年第7期41卷 1133-1141页

作者： Han-Bin Wang Hong-Chi Tian Shi-Jia zhang Bing Yu Nan-Ying Ning Ming Tian li-qun zhang Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials Beijing University of Chemical TechnologyBeijing100029China Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical TechnologyBeijing100029China Shandong Dawn Polymer Material Co. Ltd.Longkou265700China

Methyl vinyl silicone rubber (MVQ)/polypropylene (PP) thermoplastic vulcanizate (TPV) combines the good melt processability, recyclability and sealing performance as well as biosafety, stain and fluid resistance, and thus it is especially suitable in bio-safety areas and wearable electronic devices, etc. Nevertheless, the compatibility between MVQ and PP phases is poor. A big challenge on the compatibilization of MVQ/PP blends is that neither MVQ nor PP contains any reactive groups. In this study, a dual reactive compatibilizer composed of ethylenemethyl acrylate-glycidyl methacrylate terpolymer (EMA-co-GMA) and maleic anhydride grafted polypropylene (PP-g-MAH) was designed for the compatibilization of MVQ/PP blends. During melt blending, a copolymer compatibilizer at the MVQ/PP interface can be formed because of the in situ reaction between EMA-co-GMA and PP-g-MAH. The thermodynamic predict of its compatibilization effect through calculating the spreading coefficient of the in situ formed copolymer indicates that it can well compatibilize MVQ/PP blends. The experimental results show that under the GMA/MAH molar ratio of 0.5/1, the interface thickness largely increase from 102 nm for non-compatibilized blend to 406 nm, and the average size of MVQ dispersed phase largely decreases from 2.3 µm to 0.36 µm, the Tg of the two phases shifts toward each other, the mixing torque and mechanical properties of the blend are increased, all indicating its good compatibilization effect. This study provides a good compatibilizing method for immiscible MVQ/PP blends with no reactive groups in both components for the preparation of high performance MVQ/PP TPVs.

关键词： Methyl vinyl silicone rubber(MVQ) Polypropylene(PP) Immiscible polymer blends Reactive compatibilization

Catalytic hydrolysis of phosphate diester (BNPP) and plasmid DNA by mononuclear macrocyclic polyamine metal complexes

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Chinese Chemical Letters 2009年第5期20卷 523-526页

作者： Qing Xiang Xiang li qun zhang Xiao Qi Yu Ru Gang Xie Department of Chemistry and life Science Leshan Teachers College Leshan 614004 China Department of Chemistry Sichuan University Chengdu 610064 China

The activities of the catalytic hydrolysis of phosphate diester （BNPP） [bis（p-nitrophenyl）phosphate diester] and plasmid DNA （pUC 18） by mononuclear macrocyclic polyamine metal complexes have been investigated in this paper. The results showed that the highest activity in hydrolysis of BNPP was obtained with le--Zn（II） complex （composed of lipophilic group） as catalyst. The hydrolysis rate enhancement is up to 3.64 × 10^4 fold. These metal complexes could effectively promote the cleavage of plasmid DNA （pUC18） at physiological conditions.

关键词： Catalytic hydrolysis Macrocyclic polyamine Zn(II) complex BNPP Plasmid DNA