最新刊期
卷 26 ， 期 9 ， 2013
- 摘要：Coordinative chain transfer polymerization (CCTP) based on the single-site transition metal based catalyst and chain transfer agent is a kind of method for olefin polymerization. CCTP can be used for tuning the microstructure and architecture of polyolefin efficiently, and is paid attention to widely by the academic and industrial. The basic mechanism of CCTP was discussed, and then controlled/living catalyzed chain growth and chain shuttling polymerization (CSP) was also discussed due to the similar reaction mechanism. The coordinative chain transfer homopolymerizaiton and copolymerization of ethylene, propylene and long chain α-olefin were reviewed and discussed. The research and develop of novel polyolefin materials based CSP method were also reviewed and discussed. The perspective of CCTP was discussed in the end.关键词：α-Olefin;Coordinative chain transfer polymerization;Catalyzed chain growth;Chain shuttling polymerization;Novel polyolefin materials
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发布时间：2022-09-18 - 摘要：According to the great demand of reducing processing energy consumption, recycling of waste polymers and using of renewable resources in polymer industry, we have innovatively presented and studied the polymer new processing method and technology based on the volume elongational rheology. The mechanism and structure of vane plasticating and conveying process method based on the volume elongational deformation have been discussed as well as the whole plasticating and conveying process. The technology characteristics and advantages and the blend characteristics of vane extruder are also discussed in this paper from the fields of processing different material systems, especially for the multiphase and multicomponent composite materials, polymer/biomass composites, polymer/inorganic nanoparticles composites, etc. The results show that compared to the conventional screw processing technology, the new technology and equipment shows many outstanding advantages, such as wider adaptability of materials, shorter thermo-mechanical history of the plastics processing, better mixing effects, higher quality of the products, etc.关键词：Elongational deformation;Processing;Plasticating and conveying;Mixing
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发布时间：2022-09-18 - 摘要：The historical events and recent important progress in polymer/clay nanocomposites are reviewed. It is stressed that the organic modification of clay is key to the preparation of high performance nanocomposites, with special emphasis on the mechanical property,rheology and polymer blend nanocomposite.关键词：Clay;Nanocomposites;Mechanical property;Rheology
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发布时间：2022-09-18 - 摘要：Rheology of particle filled polymer (PFP) melts is one of the most important subjects in polymer science. PFP melts exhibit diverse complicated rheological phenomena depending on the structure of filler particles, the chemical nature of the polymeric matrix and the interfacial interaction. However, there are also some universal and general rheological rules among diverse experimental systems. The main experimental phenomena and results from theoretical (model) studies involved in dynamic rheology of PFP melts are summarized in this paper. The common views achieved and the scientific controversies remained so far are pointed out after heavily analyzing extensive investigations on the liquid-to-solid transition of PFP melts, the molecular relaxations, the so-called "zero shear rate" viscosity and "equilibrium" shear modulus, the time-concentration superposition principles, the two-phase model and the nonlinear viscoelasticity. Some perspectives on further studies on rheology of PFP melts are given.关键词：Particle filled polymer;Dynamic rheology;Liquid-to-solid like transition;Molecular relaxation;Time-concentration superposition principle;The two-phase model;Nonlinear viscoelasticity
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发布时间：2022-09-18 - 摘要：Polymer mechanochemistry is an interdiscipline based on polymer chemistry and mechanics, studying the activation, degradation and synthesis (crosslinking and copolymerization) of polymer materials induced by stress. Prof. Xu Xi, an academician of Chinese Academy of Science, was the founder of the Chinese polymer mechanochemistry. Since the 1950s, he and his research team from Sichuan university have applied ball milling, ultrasound, high speed stirring, pan-milling, jet milling, etc., to polymer solution, melt and solid, so as to develop novel polymer materials with high-performances, providing simple, efficient, economic and clean methods for preparation of high-performance and multi-functional polymer materials as well as recycling and reutilization of waste polymer materials. This paper briefly introduces a part of the research work on polymer mechanochemistry of Prof. Xu Xi and his research team.关键词：Polymer mechanochemistry;Ultrasound;Solid state milling;Polymer materials
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发布时间：2022-09-18 - 摘要：As the lighest solid material, aerogel, which is generally derived from so-gel process and dried by supercritical drying, has a wide range of potential applications for its low density, high porosity, large specific surface area and low thermal conductivity. However, the fragility and the complicated drying methods always restrain the utility of aerogels. Since aerogel was first created, researchers have made tireless effort to simplify the drying methods and strengthen the mechanical properties of aerogels with novel starting materials, endowing aerogels new functions. In this paper, recent progresses of aerogel research have been reviewed which focus mainly on the preparation and characterization of organic aerogels and organic-inorganic hybrid aerogels.关键词：Aerogel;Carbon material;Organic-inorganic hybrid
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发布时间：2022-09-18 - 摘要：Mesophase pitch is the important feedstock for industrial carbon. The industrial carbon materials based on mesophase pitch include carbon fibers, graphite electrodes, and carbon materials for thermal management. The synthesis technology of mesophase pitch is primitive that does not meet the requirements of high quality industrial carbon. The issues come from lack of molecular characterization and poor understanding of the reaction mechanisms. As a result, the product quality of mesophase pitch suffers. The future of mesophase pitch synthesis lays on the pitch molecular characterization. Only through effective measurement of the molecular weight distribution and quantitative description of the structural asymmetry, will the empirical definition of mesophase pitch be updated, a scientific definition be given based on the molecular weight and molecular structure, and the synthesis of mesophase pitch get improved. To understand the reaction mechanisms one will not only measure the mesophase pitch molecular weight distribution and characterize the molecular structural asymmetry, but establish the models for degradation and polymerization of aromatics mixtures with the help of computers. The accurate molecular characterization and reaction mechanisms will then serve the mesophase pitch product quality well.关键词：Mesophase;Pitch;Synthesis;Aromatics;Characterization
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发布时间：2022-09-18 - 摘要：As one of the five general purpose synthetic resins, polypropylene (PP) has the properties of non-toxicity, tasteless, low density, high stiffness, high impact strength, and good chemical resistance. PP can be made to weave product, injection product, film, pipe, and so on, and can be used widely in the package, automobile, household electrical appliances, building materials, commodity, and so on. Catalyst technology is the core of PP technology. Polymerization process is the key of mass production of PP with low cost. Development of new product is important method for the improvement of properties of PP and expanded using range. In this paper, the latest advance of research and development of PP catalyst was summarized, especially the gas phase polymerization processes of PP with high growth rate were introduced, and the usage of PP with high performance in the high-end fields, such as automobile, medical package, pipe, film, and so on, was prospected.关键词：Polypropylene catalyst;Electron donor;Gas phase polymerization process;Novel product
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发布时间：2022-09-18 - 摘要：Poly(propylene carbonate) (PPC) is a new completely biodegradable plastic based on carbon dioxide. Polymerization of PPC is not only one of the effective routes for utilization of carbon dioxide, but is expected to become a partial substitute for the traditional plastics. Focusing on the core issues which limit the large-scale application of PPC in this paper: poor mechanical and thermal properties, and starting from the three areas including chemical modification, blending modification and reinforcing modification, we have reviewed the recent progress in current situation and property modification of PPC, and have discussed the crucial problems in the PPC modification, and have also proposed the breakthrough of PPC with high performance, which could provide a theoretical guidance for the application of PPC. Finally, the outlook for the PPC modification and its future is summarized.关键词：Poly(propylene carbonate);Glass transition temperature;Mechanical properties;Thermal stability
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发布时间：2022-09-18 - 摘要：Micro-/nanolayer coextrusion is one of efficient and convenient ways to fabricate alternating multilayer functional materials by combining an assembly of layer multiplying elements (LMEs) with a conventional coextrusion block. Due to a special design of channels and force fields, LME plays a significant role in the layer multiplication and morphological control of the polymeric melt. Studies found that the confined space and rich interfaces formed in the alternating multilayer structure endowed the final products with unique mechanical, barrier, optical and other properties. This paper presents a review of the recent research progress of the structure and properties of micro-/nanolayer polymer composites in our group.关键词：Micro-/nanolayer coextrusion;Alternating multilayer structure;Morphological control;Structure and properties
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发布时间：2022-09-18 - 摘要：Marine biofouling arises from the undesirable accumulation of microorganisms, plants and marine animals on submerged surface. It has adverse effects on shipping and other marine associated activities. For example, biofouling can increase the hydrodynamic drag of ships, accelerate the corrosion of a metallic substrate, block the cooling cycle pipe, decrease the service life of marine equipment and affect aquaculture systems. Anti-biofouling is a worldwide problem due to the diversity of fouling organisms and complex marine environments. So far, the most effective approach for anti-biofouling is to use biocidal coatings containing tributyltin (TBT) formulations. However, they are detrimental to non-target organisms and the surrounding environment. It is urgent to develop environment-friendly marine anti-biofouling materials. In this paper, we review the recent progress in design and preparation of polymeric materials for marine anti-biofouling, particularly the biodegradable polymer based materials.关键词：Anti-biofouling;Environment-friendly;Protein resistance;Degradation
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发布时间：2022-09-18 - 摘要：Acrylamide-based water-soluble polymers have been widely used in the tertiary oil recovery process, but their poor salt tolerance and thermostability impeded their use in high-temperature and high-salinity oil reservoirs. To overcome such deficiencies, Hourdet et al proposed a novel concept of "thermoviscosifying water-soluble polymer" and pioneered the research in this area. Such an idea has attracted the attention from both polymer and petroleum communities. Based on authors work in this area, this paper introduces the principle, categories, synthesis procedures, as well as aqueous solution properties of thermoviscosifying polymers including those based on N-isopropylacrylamide, polyethylene oxide and N-(1,1-dimethyl-3-oxobutyl)-acrylamide. Current challenge and future trend have been pointed out to close this review.关键词：Thermoviscosifying polymer;Smart polymer;Water-soluble polymer;Enhanced oil recovery
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发布时间：2022-09-18 - 摘要：Micromolding of polymer materials and polymer composites has gained increasing technological interest because of the growing demands on devices with microscale dimension. This review provides a state of art introduction to the key features of microinjection molding. Progresses on the study of materials for microinjection, the characteristics of various microinjection molding machines and their plasticization behavior, the design and fabrication of micromould, and processing-structure-property relationship of micro parts are discussed.关键词：Polymer;Composite;Micro molding method
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发布时间：2022-09-18 - 摘要：Natural protein fiber has been widely used in the textile area due to its excellent dyeing property, high moisture regain, air permeability, and good compatibility with human skin. However, it is very important to find some new applications for those versatile natural fibers according to their special properties. These years, some materials are developed into small size such as Nanometer or micrometer particle, their specific surface area and chemical activity are greatly increased. In this paper, the study of the natural protein fiber powder will be reported including the study on the performance of the natural protein fiber powder, and its application in new fiber developing, new membrane developing, and biomaterials developing, etc.关键词：Natural protein fiber;Powder;Regeneration;Structure;Application
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发布时间：2022-09-18 - 摘要：Solvent-free nanofluids are generally referred to as the nanohybrids that consist of a rigid core and soft organic shell, where the shell is typically fabricated by grafting flexible charged organic oligomers to the surface of nanostructures. This novel gallery of hybrid material shows remarkable liuqid-like behavior in absence of any solvent at ambient temperature. With respects to the characteristic ionic bond that supports the core/shell building blocks, they can be regarded as nanoscale ionic materials or supermolecular ioni liquids. Meanwhile, the unique liquid manner also wins them the name of self-suspended nanoparticles and dry nanofluids. In this contribution, recent advances in researches on solvent-free nanofluids, including their microstructures, typical features and flowing mechanism along with the applications of 0-2D and macromolecular nanofluids have been reviewed.关键词：Solvent-free;Nanofluids;Rheological properties
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发布时间：2022-09-18 -
An Efficient Method for Flame Retardation of Polymeric Materials with Improved Mechanical Properties
摘要：This article reviews recent developments in the field of thermotropic liquid crystalline polymer (TLCP) and the corresponding in situ composites concerning both flame retardance and reinforcement. Several phosphorus-containing TLCPs with high flame retardance are discussed, and the corresponding composites with thermoplastics such as PC, PC/ABS, PET and PBT are retrospected. The results show that, besides the increase in flame retardance, enhanced mechanical properties, particularly tensile strength and modulus of the thermoplastic polymers are achieved simultaneously via the in situ microfibrillation of TLCP acting as the reinforcing fibrils. The exploration of the novel method for flame retardation of polymeric materials with improved mechanical properties provides a powerful basis for the construction of flame-retardant technologies and potential industrial applications.关键词：Thermotropic liquid crystalline polymer;Flame retardance;Reinforcement- 3
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发布时间：2022-09-18 - 摘要：With the rapid development of superconducting technology, forced cooling system and large power supply, steady high magnetic field with a dozen of Tesla and pulsed magnetic field with tens of Tesla can be achieved under laboratory conditions, which enables us to investigate the magnetic response of polymers and their composites. In this review, we focus on the orientation of carbon nanotubes and the properties of their polymeric composites including mechanical, thermal, electrical, and photoresponsive properties, with or without magnetic components such as ferromagnetic iron oxides (FeOx), nickel, cobalt and their oxides, liquid crystal. We also present some main difficulties and give some prospects for research interests in the near future.关键词：Carbon nanotube;Polymer composite;Magnetic field;Orientation
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发布时间：2022-09-18 - 摘要：The physical and mathematical models of the pressure-induced melt removal melting process were established through the research on the polymer melting process in the VPCU of the vane extruder and the relationship between the solids conveying pressure and pressure-induced melt removal melting amount with the parameters were obtained. The solid compaction process was divided into the pre-compaction stage and the plastic-compaction stage. The pressure increased slowly in the pre-compaction stage and rapidly in the plastic-compaction stage. The pressure-induced melt removal melting amount was inversely proportional to the rotating speed, and was proportional to half a square of the diameter D of the stator, the quarter power of the pressure and the three-quarters power of the temperature Ts of the stator. The results showed that the predictions of the theoretical model were in good agreement with the experiments.关键词：Vane extruder;Polymer;Melting;Model
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发布时间：2022-09-18 - 摘要：The flame-retardant polyamide66 (FR-PA66) was synthesized successfully by reaction of phosphorus-containing flame retardant. Through FTIR, TGA and DTG, SEM, LOI, the structures and properties of these samples were characterized. The FTIR analysis showed that the phosphorus-containing flame retardant was introduced in the PA66’s main chain. The TGA and DTG measurement indicated that the further degradation of FR-PA66 required higher temperature (Tmax2 was about 480.56℃) after through the first degradation stage(Tmax1 was about 418.59℃)to thermal-degradation. Through LOI and SEM analysis, it was demonstrated that the LOI value of FR-PA66 has been reached 26.7, and FR-PA66 has better char-forming property.关键词：FR-PA66;Thermal stability;LOI;Char-forming
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发布时间：2022-09-18 - 摘要：Effect of irradiation cross-linking on anti-dripping property of PA6 fibers with the presence of TAC was studied. At the dose of 100kGy in N2 atmosphere, the gel content arrived at 63.23% where the flame drops decreased from 13 to 6. The reason for anti-dripping was investigated from the view of flaming phenomena, thermo gravimetric analysis and dynamic flammability test. Irradiation cross-linking strengthened the melt viscosity, increased the residue char at 600℃ and the peak of heat release rate, slowed down the flame drops for the char-forming in condense phase.关键词：Irradiation cross-linking;PA6;TAC;Anti-dripping
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发布时间：2022-09-18 - 摘要：Owning to the advantages such as easy-sampling, free of solvent, high efficiency and relative low cost of the required instruments, Successive Self-nucleation and Annealing (SSA) fractionation has been widely applied in the analysis of ethylene/α-olefin copolymers. However, it has rarely been successfully applied in the analysis of PP. In this study, the self-nucleation behavior of PP had been studied. Based on the results, obtained, a SSA thermal protocol for iPP was designed, and the influence of important parameters (the first thermal treatment temperature Ts1; holding time ts; temperature gap between adjacent Ts, ΔT; fractionation temperature region) on the fractionation results and efficiency, were thoroughly studied. The results showed that, for iPP samples, the optimal thermal parameters are Ts1=167℃, ts=15min, ΔT=4℃, cooling/heating rate=20℃/min, fractionation temperature region=167-139℃. The variation of fractionation temperature region plays a most important role in determining the efficiency of SSA. For iPP with different tacticity, one must flexibly modify the parameters above, to achieve a balance between efficiency and fractionation results.关键词：SSA;Polypropylene;Stereo-defect distribution
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发布时间：2022-09-18 - 摘要：In order to investigate the proton exchange membranes suitable for high temperature and low moisture, a new type of cross-linking reagent diglycidyl ether of bisphenol-A was introduced to react with ethylene-vinyl alcohol copolymer at certain mol ratio, then the phosphorylated EVOH/DGEBA/PPA cross-linked membranes were obtained by phosphorylating EVOH/DGEBA cross-linked membranes with polyphosphoric acid. FTIR, XRD and proton conductivity have been used to characterize the performance of membranes. The experimental results showed that the membranes have been cross-linked and phosphorylated successfully; the thermal stability and oxidation stability of membranes were improved by cross-linking reaction; the IEC value and proton conductivity of membranes increased with increasing the phosphorylation time, however, the oxidation stability decreased. The proton conductivity of membranes was higher than that of Nafion at the relative humidity of 60%, so the prepared membrane is expected to be used in proton exchange membrane fuel cell at high temperature and low humidity atmosphere.关键词：Diglycidyl ether of bisphenol-A;Ethylene-vinyl alcohol copolymer;Cross-linking;Phosphorylation;Proton exchange membrane
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发布时间：2022-09-18 - 摘要：Dynamic information regarding coordination and dissociation effects deriving from the migration of ions in poly (ethylene oxide)10:LiClO4 electrolyte under an external DC electric field has been studied by a generalized two-dimensional correlation Fourier transform infrared spectroscopy (2D FTIR COS) at 30℃. The results show that the migration of both lithium cations and ClO4-1 anions is a complicated process coupling the change of both the form and appearance sequence of carriers under the electric field, which is apparently different from that without electric field. The ionic conduction of the electrolyte under the electric field can be divided into the dissociation of coordinated ions and the diffusion of free carriers, and the activation energy of dissociation (Ei) and diffusion (Ed) is the function of perturbation and forms of ligands.关键词：Solid polymer electrolyte;2D-Correlation FTIR;Ionic conduction;Dynamics
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发布时间：2022-09-18 - 摘要：Graphene(TrG) and multi-walled carbon nanotubes (MWNTs) were used to modify the mechanical properties of silicone rubber(MVQ) and butadiene rubber(BR). The tensile strength of TrG/silicone rubber composites was improved about 14 times and the Shore A hardness was increased from 20 to 47 with 3 wt% of TrG. These properties were much higher than rubbers which were improved with MWNTs. Percolation threshold of silicone rubber conductive composites filled with TrG was 2 wt%, the conductivity of which was 1×10-5S/cm. MWNTs/silicone rubber composites were prepared by solution method, while percolation threshold was 5 wt%, the conductivity was 2.38×10-7S/cm. The same tendency had been observed in TrG and MWNTs/BR system. The different dispersion behavior of TrG and MWNTs could be contributed to the difference in their interaction with polymer matrix due to their various geometry and topology. Based on SEM and TEM analysis, the dispersion of MWNTs in silicone rubber matrix was extremely difficult in comparison with TrG, although both of them possess the same chemical structure. Both planes of graphene could interact with polymer chains, enlarge the contact area of graphene with matrix, which lead to the strong interaction between graphene and rubber. The dispersion of graphene in rubber could be obtained even in the weak interaction system such as TrG/butadiene rubber system.关键词：Graphene;Carbon nanotube;Silicone Rubber;Butadiene rubber;Van der Waals force
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发布时间：2022-09-18
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