Xi XU
,
Xiangshen ZENG
,
Shaoyun GUO and Huilin LI (Polymer Research Institute and the State Key Laboratory of Polymer Materials Engineering
,
Chengdu Uuiversity of Science and Technology
,
Chengdu
,
610065
,
China)
材料科学技术（英文）
The morphology and properties of HDPE blends with Zn-SEPDM and GR were studied through SEM and mechanical property test. The results show that as Zn-SEPDM/GR content amounts to 20%, the blend becomes an IPN in structure, and that a rather high impact and tensile strength of HDPE may be obtained after blending. The antistatic effect, the softening point,and HDT of the blend are higher as compared to HDPE/Zn-SEPDM/ZnSt (zinc stearate).The effect of Zn-SEPDM on the compatibility the morphology and properties of IPP blends were studied by DSC, TEM and mechanical properties test. The results show that as Zn-SEPDM content exceeds 20%. Zn-SEPDM in the blend becomes continuous and an abrupt change in impact strength is incurred there from. Owing to the incorporation of ionic groups into EPDM.the strong interactions betWeen the chains make both the impact and the tensile strength of IPP remarkably higher
关键词:
Express Polymer Letters
The state-of-art and key problems of carbon nanotube (CNT) based polymer composites (CNT/polymer composites) including CNT/polymer structural composites and CNT/polymer functional composites are reviewed. Based on the results reported up to now, CNTs can be an effective reinforcement for polymer matrices, and the tensile strength and elastic modulus of CNT/polymer composites can reach as high as 3600 MPa and 80 GPa, respectively. CNT/polymer composites are also promising functional composite materials with improved electrical and thermal conductivity, etc. Due to their multi-functional properties, CNT/polymer composites are expected to be used as low weight structural materials, optical devices, thermal interface materials, electric components, electromagnetic absorption materials, etc. However, the full potential of CNT/polymer composites still remains to be realized. A few key problems, such as how to prepare structure-controllable CNTs with high purity and consistently dependable high performance, how to break up entangled or bundled CNTs and then uniformly disperse and align them within a polymer matrix, how to improve the load transfer from matrix to CNT reinforcement, etc, still exist and need to be solved in order to realize the wide applications of these advanced composites.
关键词:
polymer composites;carbon nanotubes;mechanical properties;electrical;properties;thermal properties
新型炭材料
Carbon nanotubes (CNTs) which have pi-pi conjugated electronic structure, can be functionalized by forming composites with some polymers with similar structure through van der Waals forces. CNTs coated with electronic conducting polymers (ECP) can be used in electronic devices such as supercapacitors. CNTs modified by conjugated luminescent polymers can form CNT/polymer composites, which have strong luminescence, and these photo-excited composites may be promising as electron acceptors and optoexcited devices. CNTs can also be functionalized and solubilized by attaching aminopolymers, as a result, they may find applications in biological systems. The state-of-the-art research results demonstrate that CNT/polymer composites have many promising applications to be developed and exploited.
关键词:
carbon nanotube;polymer;functional composite;nanotubular materials;conducting polymers;polypyrrole;supercapacitors
Physica Status Solidi B-Basic Research
Based on a theoretical model proposed for quasi-one-dimensional organic polymer ferromagnets, the effects of electron-electron interaction on the ferromagnetic slate are studied. Allowing for full lattice relaxation, the system is optimized by a set of self-consistent iterative equations. The results of the calculation indicate that larger on-site electron-electron repulsive interactions will make the ferromagnetic ground state of the system more stable. It is also found that the inter-site electron-electron interaction cause a charge density distribution along the main chain and consequently weakens the stability of the ferromagnetic ground state.
关键词:
Communications in Theoretical Physics
The possible ferromagnetic ground state of pi-conjugated alternant hydrocarbon chains with unequal number of atoms on two sublattices is studied by the peierls-Hubbard model. Allowing for full lattice relaxation, a set of self-consistent iterative equations are established to study this system. The stabilities of the possible ferromagnetic ground states with respect to two kinds of unsymmetric site energies are also studied. We find that the ground state of the system is a stable ferromagnetic state as a result of the topological structure of the network and the electron-electron interaction. And the unsymmetric site energies, induced by substitutions, will severely weaken the stability of the ferromagnetic ground state.
关键词:
Nano Research
Two-dimensional (2-D) layered metal-organic coordination (lead methacrylate (LDMA)) networks have been prepared in aqueous solution under mild conditions and their structure determined by single crystal diffraction. As the ligand used in our experiments is easily polymerized, these metal-organic coordination layers are therefore employed as precursors to fabricate cross-linked polymer layered materials through.-irradiated polymerization. The stabilities of the samples are significantly improved after.-irradiation. To our knowledge, this is the first time that covalent bonded polymer layered structures have been fabricated without the assistance of added surfactant or template. Such layered polymer materials cannot only act as alternatives to layered inorganic materials in some caustic environments, but also allow the generation of PbS nanoparticles (NPs) without aggregation in the polymer matrix. By exposing the polymer layer to H(2)S gas at room temperature, uniform PbS nanoparticles with an average size of about 6 nm are generated in situ. In addition, the resulting PbS NPs exhibit near-infrared (NIR) luminescent properties, which suggests the composite materials may be useful as active optical elements at communication wavelengths from 1300 to 1550 nm.
关键词:
PbS nanoparticles;layered material;near-infrared;gamma-irradiated;polymerization;in situ
Solid State Communications
The possible ferromagnetic ground state of a theoretical model proposed for quasi-one-dimensional organic polymer ferromagnets is investigated in detail. Within the self-consistent-field Hartree-Fock approximation, allowing for full. lattice relaxation, the system is studied self-consistently. We find a critical interaction, which is determined by the competition between the electron-electron interaction and the electron-phonon coupling. When electron-electron interaction is larger than the critical value, the ground state of the system is a stable ferromagnetic state. It is also found that in this stable ferromagnetic state the pi-electrons SDW will become very strong, and almost zero dimerization happens for the main chain.
关键词:
E.Bayraktar
,
F.Montembault
,
C.Bathias
材料科学技术（英文）
The study of microstructural network and damage mechanism of polymer and rubber, although deceptively simple, involves a complex interplay between material properties and service conditions. So, the study of the texture, deformation and the failure of rubber specimens are of considerable practical interest. In fact, the occurrence of defects such as the initiation and the growth of cavitations in rubber specimens in working conditions is an important problem. These deal with the improvement of microstructure (for delaying instability) in order to obtain a higher service capacity. The scope of the present paper is, therefore, to evaluate principal mechanisms, in-situ observation of damage at mesoscopic, microscopic and macroscopic levels by using X-ray computed tomography (CT) installed in the ITMA research centre for confirming the behaviour of natural rubber (NR) and styrene butyl rubber (SBR) specimens used in automotive and aeronautical fields.
关键词:
X-ray computed tomography
,
null
,
null
,
null
Andrej Atrens
材料科学技术（英文）
Corrosion research by Atrens and co-workers has made significant contributions to the understanding of the service performance of engineering materials. This includes: (1) elucidated corrosion mechanisms of Mg alloys, stainless steels and Cu alloys, (2) developed an improved understanding of passivity in stainless steels and binary alloys such as Fe-Cr, Ni-Cr, Co-Cr, Fe-Ti, and Fe-Si, (3) developed an improved understanding of the melt spinning of Cu alloys, and (4) elucidated mechanisms of environment assisted fracture (EAF) of steels and Zr alloys. This paper summarises contributions in the following: (1) intergranular stress corrosion cracking of pipeline steels, (2) atmospheric corrosion and patination of Cu, (3) corrosion of Mg alloys, and (4) transgranular stress corrosion cracking of rock bolts.
关键词:
Stress corrosion cracking
,
null
,
null
