Materials and Properties
Yang XING, Chong WANG, Zhongyu FU, Shiyu LIU, Huixuan ZHANG
Abstract (
921 )
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The rheological behaviors of polyacrylonitrile (PAN)/dimethyl sulfoxide (DMSO) solutions were measured with a rotary rheometer, and the relationships of apparent viscosity (ηα), storage modulus, loss modulus and loss tangent angle with the temperature, concentration and shearing conditions were investigated. The effect of PAN chain entanglement on the rheological behavior and molecular structure of PAN/DMSO solution were studied. The results indicated that pre?shear could effectively make the PAN chains disentangle to some extent and therefore resulted in a decrease of the ηα of PAN/DMSO solution. Moreover, the effect of shear on the ηα was reduced with increasing the temperature and decreasing the concentration. As a result, the rheological performance of PAN/DMSO solution was improved.
Juanjuan ZENG, Haiji CHEN
Abstract (
657 )
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Phenolic amines were synthesized through the Mannich reaction among cardanol, paraformaldehyde and diethylenetriamine and then reacted with poly(propylene glycol diglycidyl ether) to produce an epoxy resin curing agent. Furthermore, a two?component epoxy resin grouting material was prepared by the curing reaction of E?51 and F?51type epoxy resins with this curing agent in diluent 692. The synthesis process of curing agent, the curing behavior of epoxy grouting material and the properties of consolidation body were investigated extensively. The result indicated that the optimum feed ratio was achieved for the synthetic curing agent at the n(aldehyde)/n(phenol)/n(amine)/n(ether) molar ratio of 1/1.1/1.2/0.4. When the curing agent/epoxy resin volume ratio was set at 100/(80~120), the slurry exhibited an initial viscosity of 400~500 mPa·s and a gel time of 25~45 min, and the performance of the solidified body met the requirements from the standard JC/T 1041-2007. Moreover, the viscosity of the slurry decreased gradually and then increased rapidly with time before the gel happened, and the gel time increased with a decrease of service temperature.
Cun ZHOU, Chunlong ZUO
Abstract (
904 )
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333
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Water?based phosphoric acid?modified epoxy resin (PAER) was prepared by using phosphoric acid and epoxy resin (E20) as raw materials, and its molecular structure was characterized by Fourier?transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The potassium salt of phosphoric acid?modified epoxy resin (PAERK) was obtained by a neutralization reaction of PAER with KOH, and then the fluorine?containing epoxy resin potassium salt (PAERKF) was prepared by using PAERK and fluorine?containing surfactant as raw materials. The results indicated that the optimum sizing concentration and coating amount for PAERKF was 0.6 wt % and 5.0 mg/g, respectively. After modification with PAERKF, the contact angle between the polyacrylonitrile (PAN) fiber and water reached 146.94°, indicating a highly hydrophobic feature. The PAERKF?modified PAN fiber achieved a dispersion coefficient of 0.89 in the epoxy matrix, and the dispersibility of fibers in the matrix was improved.
Jingyue NI, Kesong YU, Yae TANG, Shihong CHEN, Xiangdong WANG
Abstract (
709 )
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584
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The polylactic acid (PLA)/poly (butylene adipate?butylene terephthalate) (PBAT) blends were prepared by melt blending. The effect of the content of epoxy chain extender (CE) as a compatibilizer on the rheological behavior and crystallization behavior of the blends was investigated, and the foaming behavior of the blend containing 5 phr CE under the cold crystallization condition and the tensile properties of the resulting foams were studied. The results indicated that the blending system presented an increase in compatibility and crystallization rate with an increase of CE content, and its expandability was improved. The micro?nano complex cells were obtained for the blend foam with 5 phr of CE. This blend foam achieved a cell density of 1013 cells/cm3 as like as the PLA foam, and its elongation at break increased by 40%.
Yanzhi SONG, Zhifeng ZHU, Shian LI
Abstract (
833 )
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374
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To overcome the rigid and brittle defects of starch films, the octenylsuccinate?carboxymethyl oil?water amphiphilic starch (OS?CMS) was synthesized through a two?step reaction using corn starch, chloroacetic acid and octenylsuccinic anhydride as raw materials. The chemical structure and crystallinity of the resulting films were characterized by Fourier?transform infrared spectroscopy and X?ray diffraction, respectively, and the mechanical evaluation were conducted for the samples at different molar ratios of functional groups and degrees of starch modification. The results indicated that the surface modification led to a decrease in crystallinity of OS?CMS films. The breaking strength of OS?CMS films increased with an increase of molar ratio, but their elongation at break increased at first and then tended to decrease. As a result, the films achieved an improvement in toughness. The OS?CMS films obtained a maximum value in elongation at break at the OS/CMS molar ratio of 1/1, and their breaking strength and elongation at break were found to increase gradually with an increase of the degree of denaturation, indicating an enhancement in mechanical performance.
Xiaolong LU, Xuanyu LIU, Enpu DING, Beibei ZHANG, Xiang YU, Gang QIN
Abstract (
760 )
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928
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Highly efficient and recyclable polyacrylonitrile (PAN)/TiO2 nanofiber membranes were prepared by means of electrospinning and hydrothermal treatment, and their morphology, crystalline structure, mechanical properties and photocatalytic activity were characterized by SEM, XRD and the degradation efficiency of methylene blue (MB). The results indicated that the fiber diameter was reduced effectively with the addition of tetrabutyl titanate which could be successfully transferred into anatase TiO2 under the hydrothermal treatment. The strength of the PAN/TiO2 membranes was found to be higher than that of pure PAN membrane. The membranes exhibited a maximum photocatalytic degradation efficiency of 94.8 % for MB after ultraviolet irradiation for 120 min, and a great photocatalytic activity was maintained for the membranes after five?time recycling.
Xiangyu WANG, Yuxia ZHANG
Abstract (
637 )
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429
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PLA is anchored onto OMMT in a torque rheometer by ADR, and the resultant PLA/OMMT/ADR is compounded with PBAT to make （PLA/OMMT/ADR）/PBAT nanocomposite. Facial tension of various composites and interfacial tension between different phases were calculated by testing the contact angle, leading to the wetting coefficient between PLA and PBAT and OMMT, respectively. Microstructure of the nanocomposite was observed by TEM and SEM. IR?FT shows that PLA was anchored onto OMMT. With the increasing of ADR, the wetting coefficient between different phases decreased, leading to the transformation of OMMT in the interfaces between PLA and PBAT to PLA domain. It can be seen from TEM that OMMT was exfoliated and well distributed in （PLA/OMMT/ADR）/PBAT system, which is attributed to the improvement of affinity between PLA and PBAT, as well as the movement of OMMT from PLA domains to the interfaces between PLA and PBAT and PBAT domains. Pictures from SEM shows that with the increasing loading of ADR, the interfaces between PLA and PBAT became blurred, which means the increase of the compatibility between PLA and PBAT.
Zhi LIU, Bo WU, Guangkai HOU, Fangtao RUAN
Abstract (
724 )
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389
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In this study, a type of superhydrophobic poly(methyl methacrylate) (PMMA)/simethicone complex membranes was fabricated by a one?step electrospinning technology, and the effects of PMMA and simethicone concentrations on the fiber morphology and membrane wettability were investigated systemically. The SEM observation indicated that there were beaded fibers appearing with an increase of oil content, and the bead volume also increased. The complex membranes exhibited a superhydrophobic nature with a water contact angle 150.6° at the PMMA/simethicone mass ratio of 6/8. This phenomenon could be explained by the fact that the increased bead could capture more air and therefore reduced the contact area between the water phase and membrane interface. This fabrication method can control the hydrophobic property easily by adjusting the proportion of oil phase and benefits the preparation of special wettability surface and the application in oil?water separation accordingly.
Processing and Application
Junxiang CHEN, Nanhong FU, Ruixue WANG, Kaifang DANG, Weimin YANG, Pengcheng XIE
Abstract (
597 )
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315
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In this study, micro?scale pores were obtained on the metal surface by a simple chemical cleaning and etching method, and then a polymer was bonded with the resultant metal through composite injection molding. The surface microstructure was achieved at different scales by changing the dipping time of aluminum sheets in solution, and the influence of surface microstructure on the interface bonding strength was investigated. The results indicated that there were dense micro?sized pores on the surface of aluminum sheets after treated with hydrochloric acid. With an increase of corrosion time, the pore diameter and pore density of the metal surface increased at first and then tended to decrease. The interfacial bonding strength was found to increase at first and then decrease as a result of the combining effect of pore size and pore density, and it reached a maximum value of 10.24 MPa. This surface treatment method provides a theoretical foundation for engineering applications in the fields of automotive interiors, architectural decoration and electronic product enclosures.
Xiliang SHAN, Yulu MA, Linsheng XIE, Huihao ZHU, Dayou DING
Abstract (
510 )
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327
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The mixing process of calcium carbonate?filled PE?HD composite in the LIST horizontal differential biaxial mixing equipment was simulated by a discrete element method, and the effects of addition speed and mixing rate on the material filling degree, residence time distribution and mixing uniformity of compounds in the self?cleaning mixer were investigated. The results indicated that the axial conveying capacity of the self?cleaning mixer was mainly derived from the pushing effect of subsequent materials. The optimum mixing effect could be achieved at a shaft rotation speed of 40 r/min and a feeding rate of 10 kg/h.
Bohong HAN, Yandong HE, Xiangzhe ZHU
Abstract (
662 )
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180
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A transient calculation method is used to simulate the rotor of a 4WS?tpye internal mixer. The maximum velocity of flow field was found to distribute on the top of the rotor ridge, where the reflux was prone to take place. The fluid velocity in the rotor clearance increased gradually and then tended to be stable with the running time of rotor until. There is a great influence on the fluid center area but a small impact on the near?wall area from the change of the rotating direction of the rotor. With the rotation of the rotor, the pressure difference between the propulsion area and backpressure zone decreased gradually, and the reflux phenomenon decreased accordingly.
Jinkun WANG, Zhenghua MENG, Wei GUO, Haosheng HU, Lei ZHOU
Abstract (
485 )
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398
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In this paper, taking the in?mold decoration test plate as a research object, the influence factors of film heat?lag effect and the influence on the molding process were analyzed by simulation and experimental methods. The results indicated that the film heat?lag effect generated the hysteresis of temperature change for the moving mold side compared to the fixed mold side, and there was a maximum temperature difference of 8.6 °C under the experimental conditions. The film heat lag decreased with an increase of mold temperature, but increased with the increase of melt temperature and film thickness. The filling and cooling of the melt were influenced by the film, resulting in uneven cooling of the product. The heat?lag effect of the film led to an increase in warpage of the product.
Additive
Xiwei XIE, Yunxuan WENG, Caili ZHANG, Xinyu SONG
Abstract (
709 )
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369
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18 )
The bamboo powders (BP) were surface modified with aluminic acid ester and then melt blended with poly(terephthalic acid succinate) (PBAT) to prepare a series of PBAT/BP composites through a heterogeneous kneading twin?screw extruder. The mechanical, thermal properties and microstructure of PBAT/BP composites were characterized by a universal testing machine, thermogravimetric analysis and scanning electron microscopy. The results indicated that the thermal stability and mechanical properties of PBAT/BP composites were improved due to the surface modification of BF with aluminic acid ester. When 1 wt % of aluminic acid ester was incorporated, the PBAT/BF composites achieved an increase in impact strength by 42 %, and in elongation at break by 92.7 %.
Minxian LI, Jing YU
Abstract (
881 )
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499
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A calcium/zinc benzoate?oleate liquid heat stabilizer was prepared by a one?pot reaction using oleic acid, benzoic acid, zinc oxide and calcium hydroxide as raw materials and oxidized vegetable oil as a solvent, and its static thermal stability and synergistic effect with auxiliary heat stabilizers like beta?dione, phenylenediisooctyl phosphite and pentaerythritol were investigated by means of the Congo red test paper and thermal aging methods. The thermal stability of the stabilized poly(vinyl chloride) (PVC) samples with optimized formulation was measured by torque rheometer, UV?visible spectrometer and scanning electron microscope. The results indicated that the PVC sample stabilized with this composite heat stabilizer achieved a static heat stabilization time of 50 min, and there was a synergistic effect with phenyl diisooctyl phosphite on the stabilization system. The PVC sample exhibited an optimum stabilization time up to 71 min and a dynamic thermal stabilization time up to 970 s, and an equilibrium torque of 37.3 N·m. The UV?visible spectroscopic analysis suggested that this composite heat stabilizer had a strong capability to inhibit the formation of conjugated polyene with more than 3 conjugates. The SEM observation showed that the composite heat stabilizer was uniformly dispersed on the surface of PVC particles due to the good compatibility between two parts, and as a result, the composite heat stabilizer was able to inhibit the degradation of PVC within 60 min.
Machinery and Mould
Xin WANG, Linfang DU, Longfei CAI, Chi ZHANG
Abstract (
579 )
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533
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Aiming at the current situation that the traditional cold runner mold requires the manual removal of freezing materials in the gating system and the poor technical effect of cold?cutting gate, a mobile phone case was taken as an example to design a injection mold for the mobile phone case with a hot?cutting gate function. According to the structural characteristics of the lapping and side gate, an accurate motion cutting device was designed to ensure the clean gate cutting, and then a drive cylinder with appropriate infeed time was established by the finite element analysis method. Moreover, a reasonable ejector and cooling mechanism were designed to ensure the product and gating system ejected safely after separation and cooling.
Zijun ZHENG, Guohua XIAO, Zhongliang SHEN, Shaozeng YANG
Abstract (
558 )
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438
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A type of four?layered lamination mold was designed to realize the high efficiency injection production of a game console handle, which could achieve a quadrupling quantity in the mass production for single injection molding on the basis of an ensured molding accuracy of the plastic part. The structure of the four?layered mold was composed of four single?layer molds with the same structure, which were arranged and assembled in a certain spatial sequence, and then a vertical injection?molding machine was adopted for injection molding. A hot runner in a two?plate mold form for opening twice was adopted for the design of single?layer mold structure. The first mold opening was operated for the separation of the hot runner nozzle and the cold runner part of the plastic part, and the second one was operated for the demolding of the plastic part from the cavity insert. In order to solve the problem that the ejecting plate had no power to eject after the single?layered mold was assembled in four layers, a pull rod was symmetrically arranged on the side of the single?layered mold, which could make the opening power transfer into the ejecting force of the ejecting plate in the single?layered mold. Such a design could well solve the problem that the ejecting element of each single?layer mold had no power to eject the plate after the single?layered mold was installed in four layers. The layout of mold structure and the design of driving mechanism are reasonable and can be taken as a good reference for the engineering design.
Review
Junwei LIU, Liang TONG, Chen WANG, Zhaoshu CHEN
Abstract (
821 )
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692
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This paper introduced the application of various nonmetallic materials in automobile interior decoration in terms of polymer plastics, fabrics, leathers, coatings, and rubbers, and their flame?retardant properties along with the relevant flame?retardant mechanisms were further summarized. Moreover, the research progress in the flame retardancy for various materials was reviewed on the basis of the experimental results of limit oxygen index, vertical combustion grade, cone calorimeter, and the associated mechanical properties. Finally, the future direction in research of non?metallic materials for automobile interior decoration was prospected.
