Materials and Properties
LI Wenchao, ZENG Jia, CHEN Chenghong, ZHOU Liuliu, WU Shijian
Abstract (
842 )
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A type of copolymer polypropylene （coPP）/isotactic polypropylene （iPP） self?reinforced wire material was prepared by composite extrusion and die drawing. A high-strength all-polypropylene composite sheet was prepared via hot-pressing with this wire material as a reinforcement and coPP as a matrix， and its mechanical properties， dynamic mecha?nical properties， and recyclability were investigated. The results indicated that the tensile strength and bending strength of the composite sheet reached 160 MPa and 63 MPa， respectively. The addition of the reinforcement greatly improved the energy storage modulus of the composite sheet but reduced its loss factor；A recycled sheet was obtained through pulverizing， granulating and hot?pressing with 25 wt% of reinforced composite board. Its tensile strength decreased by only 7.3 %， and there was almost no loss in its bending strength. The internal coPP and iPP had good compatibility， indicating good recyclability of the composite sheet.
WEI Daidong, ZENG Juanjuan, CHEN Haiji
Abstract (
1063 )
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825
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A permeable epoxy coating was prepared through a combination of bisphenol-A epoxy resin （E51）， furfural， acetone phenolic modified amine， 2，4，6-tris（dimethylaminomethyl）phenol （DMP-30） and other additives， and its reaction mechanism was analyzed. The influence of different additives on the film-forming ability of the coating was discussed. The depth of penetration to the surface of concretes with different strength grades along with other basic properties was also investigated. The results indicated that the BYK-333-modified coating exhibited an optimum film-forming ability and good permeability. The coating achieved bonding strength of 4.5 and 3.6 MPa on the dry base concrete surface and the wet base concrete surface， respectively. Moreover， the coating gained a maximum penetration depth of 5 mm on the C30 concrete surface， indicating good chemical resistance.
ZHAO Jingang, LIU Zhaogang, HAO Wei, LI Mei, HU Yanhong, WU Jinxiu, FENG Fushan, LI Shuai
Abstract (
991 )
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111
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Cerium pmethyl benzoate （CPB） was prepared by means of a metathesis method， and its molecular formula was determined to be Ce（C8H7O2）3·2H2O. The thermal stability of CPB on PVC was further investigated. The results indicated that when CPB was used alone as a thermal stabilizer for PVC， the resultant PVC compound exhibited poor thermal stability and discoloration resistance. However， there is a good synergetic effect on PVC by a combination of binary， ternary and quaternary compounds of CPB with other thermal stabilizers， resulting in an improvement in thermal stability. When the mass ratio of cerium benzoate to calcium zinc composite system and pentaerythritol was set to 2/1/2， the PVC compounds achieved an optimum thermal stability with thermal stability time of 42 min as well as optimum discoloration resistance. CPB also exhibited a good plasticizing capability. When CPB was used as a stabilizer for PVC， the resultant PVC compounds revealed a decrease in plasticizing time， plasticizing torque and equilibrium torque but a significant increase in dynamic thermal stability time. CPB can capture the HCl gas released during the degradation of PVC to generate CeCl3， reducing the catalytic effect of HCl on the degradation of PVC and improving the thermal stability of PVC accordingly.
HE Peixi, LAI Jiamei, WAN Yibiao, ZHAO Chenxu, HUANG Zhichao
Abstract (
862 )
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1868
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This paper reported an investigation on the three-point bending properties of the foam sandwich composites prepared through stitching and rib reinforcement methods. A three-point bending experiment was carried out with a universal testing machine for the seamed and unstitched carbon fiber， glass fiber， and glass-carbon hybrid fiber foam sandwich composites， with the corresponding load-deflection curves presented in the paper. The flexural properties of the seamed carbon fiber foam sandwich composites were further studied by means of a reinforcing rib method. The results indicated that the performance of the glass-carbon hybrid fiber foam sandwich composites was improved in comparison with the glass fiber foam sandwich composites. The introduction of reinforcing ribs increased the bending strength of the stitched carbon fiber foam sandwich composites from 17.79 MPa to 37.47 MPa. The bending performance of the stitched carbon fiber foam sandwich composite was improved with an increase in the number of reinforcement ribs. At the same number of reinforcement ribs， the sandwich composites achieved optimum bending strength of 46.96 MPa when the reinforcement ribs were laid in parallel. Next was under the 20 ° cross-laying of the reinforcement ribs and least was under the cross-laying of the reinforcement ribs.
XIONG Huixia, ZHAO Wenjie
Abstract (
911 )
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520
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In this paper， a type of polystyrene?grafted poly（butyl acrylate） （PS-g-PBA） emulsion was synthesized and then used to modify cement mortars. The effects of mass ratios of PS to PBA and polymer to cement on the fluidity， water reduction effect， mechanical properties and capillary water absorption rate of PS-g-PBA emulsion-modified cement mortars were investigated. The results show that the water reduction effect of the three cement modifiers is excellent， and the maximum value of water reduction rate is 56.7 %. The water absorption rate of the pores of the modified cement mortar decreases obviously， and its minimum value is 0.288 kg/m2.PS-g-PBA emulsion also has an important effect on the mechanical properties of modified cement mortar.The compressive strength is generally reduced， and the flexural strength of partially modified mortar is increased， and its maximum value is 8.1 MPa.The PS-g-PBA cement modifiers developed by this work are suitable for use in the modification of cement mortars.
LIU Yuan, NIE Shengqiang, ZHANG Chunmei, WANG Yi, XIE Xiangyu, LUO Jun
Abstract (
726 )
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424
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A carbon nanofiber membrane with good flexibility was prepared through electrospinning with a mixture of benzoxazine， PAN and iron acetylacetonate. The results indicated that the N， O and S heteroatoms were successfully introduced into the as?prepared carbon nanofiber membrane through electrospinning in terms of the chemical structure designed benzoxazine， and these introduced heteroatoms effectively enhanced the pseudocapacitance of the electrode and its wettability with the electrolyte. Furthermore， eco?friendly Fe3O4 with excellent pseudocapacitance was deposited on the surface of the carbon nanofiber membrane to obtain a flexible supercapacitor electrode material （Fe3O4@BENCNFs） with excellent electrochemical performance. The three?electrode test results indicated that the Fe3O4@BENCNFs achieved a specific capacity of 160.1 F/g at a current density of 1 A/g.
LI Lei, ZHU Qianqin, XIA Yunxia, ZHANG Junfeng, HE Lijun
Abstract (
1075 )
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865
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The development of new shoe uppers is of great significance for improving the wearing comfort and product aesthetics. In this work， we report an investigation on the preparation of polyethylene non-woven fabrics by a flash evaporation method using high-density polyethylene resins with different melt flow indexes and a mixture of difluorochloromethane and tetrafluorodichloroethane as a solvent. The morphology， contact angle， specific surface area， breaking strength and breaking elongation， thermal properties， air permeability and water resistance of the obtained woven fabrics were characterized by using of scanning electron microscope， dynamic contact angle measuring instrument， automatic specific surface area and aperture analysis tester， differential scanning calorimeter， thermogravimetric analyzer， electronic strength machine and digital air permeability meter. The results indicated that all of the non-woven fabrics were constituted with pure polyethylene ultra-fine fibers with an average monofilament diameter of 4 μm， and they achieved maximum tensile break strength of 220 N/5 cm. Such non?woven fabrics exhibited good air permeability， hydrophobicity and ink wettability. This type of non-woven fabrics exhibits a promising prospect for applications in novel shoe upper materials.
LIU Zhi, HUANG Xiaohai, GAO Bing, WU Bo, RUAN Fangtao
Abstract (
849 )
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564
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A type of hydrophobic/oleophilic functional commercial sponges based on polyurethane （PU）/poly（vinylidene fluoride hexafluoropropylene）（PVDFHFP） nanofibers composites was successfully prepared through an electrospinning technology at a high relative humidity of 90 % and a short collection distance of 6 cm. The morphology and structure of the composite sponge were characterized by SEM， FTIR and XRD， and its oil absorption performance was investigated. The results indicated that the PVDF-HFP nanofibers and PU were partially dissolved and mixed at the interface due to the solvent action of N， N-dimethyl formamide， resulting in a strong binding force. The sponges exhibited excellent hydrophobic properties and a good oil absorption ability with an oil absorption capacity of 30.8 g/g for olive oil， 25.2 g/g for lubricating oil， 16.8 g/g for dimethyl silicone oil and 26.4 g/g for n-hexane. The sponges also showed an excellent reusability， and their oil absorption could still maintain 97.2 % of the original capacity after 50 times cycles.
Processing and Application
YIN Fangfang, DANG Kaifang, YANG Weimin, DING Yumei, XIE Pengcheng
Abstract (
751 )
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440
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The reliability-based topology optimization based on a modified minimum weight with a displacement constraint model （RBTO-MMWDC） was established for the feature?integrated design of polymer products. In order to facilitate the popularization and application of this design method， a graphical user interface was developed on the basis of an optimization code， realizing the design of hollow slab section structure with a reliability index （β） of 3.0. The mechanical properties of the optimized structure were evaluated and analyzed through finite element simulation. Compared to the traditional structure， the compression resistance and bending resistance properties of the optimized structure were improved by 29.20 % and 74.93 %， respectively. The first?order natural frequency increased by 100.91 %， which effectively avoided the torsional modal shapes in the first five order modes. In addition， the C?UV9400 photopolymer for SLA was adopted as a raw material to prepare the specimens with two hollow slab structures using a stereolithography 3D printing technology. The optimized structure achieved an improvement in bending resistance strength and stiffness by 60.88 % and 55.30 %， respectively. This study provides a theoretical reference and feasible solution for the feature?integrated design of polymer products in the engineering application.
HE Jialong, GU Lin, ZHU Yuting, SONG Xiuduo, YANG Xueqin, MA Yulu, XIE Linsheng
Abstract (
906 )
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699
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On the basis of research results in the spiral compression and extension process of solid propellant， a new method was explored to establish a rheological model of solid propellant. To develop this new method， a least square method was used to fit the data obtained from the capillary rheometer test to achieve a preliminary solid propellant rheological constitutive model. The test process of the capillary rheometer was then simulated by using by a Polyflow finite element simulation software to correct the parameters of the rheological constitutive model so as to determine the final propellant rheological constitutive model. The rheological constitutive model of the propellant was established through a combination of experimental data fitting and finite element simulation. This lays a foundation for simulating the spiral extrusion process of solid propellant with a finite element method. The results indicated that there was only an error of around 10% between the real data and the data obtained from the simulation with the propellant rheological model by a combination of data fitting and numerical simulation. The obtained results were in good agreement with the expected results from the numerical simulation
WANG Duyang, CAI Zhennan, HUANG Xingyuan, WANG Long, LI Mengshan
Abstract (
676 )
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693
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There is a close relationship between the quality of the microcellular foaming material and the amount of supercritical CO2 dissolved in the polymer melt along with its dissolution rate. A finite element simulation method was adopted to obtain the equivalent diffusion coefficient under different conditions to characterize the dissolution rate. A volumetric?based experimental device was used to measure the amount of supercritical CO2 dissolved in the polymer melt under different conditions. The change of the dissolution amount at different diffusion coefficients was then calculated by the COMSOL software. Through comparing the experimental data with the simulated ones， the equivalent diffusion coefficient of supercritical CO2 in the polymer under different conditions was obtained， and its error source was analyzed. The results indicated that the amount of supercritical CO2 dissolved in the polystyrene melt increased with an increase in pressure but decreased with an increase in temperature. The equivalent diffusion coefficient calculated by simulation is in good agreement with the experimental result. The improvement of temperature and pressure resulted in an increase in diffusion coefficient. There is no more than 20 % of error between the simulated dissolution equilibrium time and the experimental value. The experimental results are in good agreement with the simulation ones. Therefore， the simulation and calculation for the dissolved amount and equivalent diffusion coefficient are of great significance and therefore can provide a theoretical guidance for the microcellular foaming process.
WANG Cheng, WENG Nanchang, NIE Yan, QIN Hongliang
Abstract (
941 )
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639
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PBT/PC alloys have a great number of excellent properties. In this paper， the characteristics of PBT/PC alloy films were studied， which included light transmittance， surface tension， surface resistance， carbon powder adhesion， printing smoothness and others that are required for document manufacture. The optimum pressing conditions for the PBT/PC alloy films with a PETG?matrix card material were investigated under a certain temperature and pressure. The image quality， peel strength and other properties of the certificate were obtained from the laminates of PBT/PC alloy films with the PETG-matrix card material. The durability of the document was studied through an accelerated aging test， and the image quality， bending and torsion performance， dimensional stability and electrical property of the document after aging were also evaluated. The results indicated that the printing image of the PBT/PC alloy films was clear and firm， and their optimum processing conditions with the PETG-matrix card material were determined to be a temperature of 135 °C， a pressure of 1.5 MPa and a time of 15~20 s. The obtained document has a clear performance image and firm peeling strength. The accelerated aging test results revealed that the image quality， bending and torsion properties， dimensional stability and electrical properties of the document could meet the requirement of the standard. The certificate can be used for at least 5 years. The PBT/PC alloy films can be used for the production of the document based on the PETG?matrix card material.
LUO Fei, HAO Lingao, WANG Tengfei, LIU Hongpeng, DANG Xudan, WANG Yaming, LIU Chuntai, SONG Yan
Abstract (
767 )
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492
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The PLA/coiled carbon nanotube （HCNT） composites were prepared through melt blending with different mass fractions of PBAT. A series of rectangular samples based on these composites were prepared through hot pressing under different pressures and packing time by using an automatic vacuum hot?pressing machine. Their glass transition temperature and multi?structural deformation at a constant stretching rate were investigated by DSC， Linkam stage and wide?angle X?ray diffraction measurement. The results indicated that the molecular orientation and the rate of orientation evolution increased with an increase in macro?deformation. For two samples with lower and higher contents of PBAT， the rate of orientation evolution increased with the increase of packing time and pressure. However， in the cases of other samples， the dependence of the rate of orientation evolution on pressure and time was not evident. This phenomenon implied there was a synergetic effect on the molecular orientation from the dispersed PBAT， free volume and HCNT. A three?element viscoelastic model was used to analyze the experimental data. The fitting results indicated that the sample with a lower content of PBAT was more sensitive to packing time， but the sample with a higher content of PBAT was more sensitive to pressure.
Additive
LIU Yi, GUO Xiaodong, BAO Lulu, SHU Cheng, LI Yonglun, WANG Yong, LI Guofeng, DU Shanming
Abstract (
680 )
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489
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A series of coal-based PP （S1003） were prepared by using different ratios of 1010/168 composite antioxidants to calcium stearate， and their thermal oxidative stability and processing stability were analyzed through oxidation induced time （OIT） test， multiple extrusion test and yellow index test at different temperatures. The results indicated that the OIT value of S1003 increased with an increase in the concentration of antioxidant 1010 in the main and auxiliary antioxidant system at the same temperature， presenting an excellent ability to capture oxygen free radicals. At the same time， the MFRs of the samples with formula 3 and formula 4 showed a slow increasing trend， indicating that the thermal oxidative degradation of S1003 was inhibited effectively. In addition， the distribution trend in yellow index showed that the color change resistance for the samples obtained from repeated extrusion was improved with an increase in the concentration of antioxidant 168. It was concluded that a proper ratio for the antioxidant composite could improve the antioxidant performance of S1003. Such a result is of great significance for the optimizing the formula proportion of composite antioxidants and prolonging the service life of coal?based PP materials.
Standard and Test
CUI Weixin, WANG Kejian, DING Li, AN Jing
Abstract (
764 )
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464
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The flowability of composite highly filled with powder was measured at different temperatures using rod-falling method， melt index tester and capillary rheometer. Their comparison shows that three methods are all applicable in measuring such flowability. At the same time， comparing the three testing methods， it is found that the rod?falling method has the advantages of easy operation and wide range in testing materials.
KONG Hao, DONG Ze, WEI Chenjie, WANG Jifen, GAO Chunfang
Abstract (
431 )
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324
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In order to improve the inspection efficiency， reduce the cost of inspection and identification， and realize the rapid and nondestructive classification of sole， a Fourier?transform infrared fingerprint spectrum and a spectral derivation were adopted to analyze the soles with five different brands among the totally 50 samples， and two classification models， Bayes discriminant （BDA） and support vector machine （SVM）， were constructed. The experimental results indicated that the fusion model based on the original data， the first derivative data， and the second derivative data was superior to the single model and the intermediate fusion model in the process of sole discrimination， which resulted in an overall classification accuracy of more than 80 %. Based on the primary model， the combination of BDA with the original first derivative model led to an overall classification accuracy of 92 %. Different fusion models can be constructed by a combination of the infrared fingerprint spectrum with the first order derivation and the second order derivation to distinguish and contrast. The rapid non?destructive identification of daily leather shoes and sneakers soles can be realized by choosing the most effective fusion model， which provides a new way for the rapid detection of cases.
Machinery and Mould
XIONG Yi, WANG Wei
Abstract (
878 )
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825
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Aim at the difficulty in the large area of undercut in all four sides of the supporting shell in the mold design， we design a scheme to divide all of the side areas into 6 sliders S1~S6 for molding according to the demolding direction. Owing to two sliders on the right side of the product， S2 and S3， with inconsistent stripper directions and large molding areas， a two-stage sequential core-pulling mechanism with an inclined guide column + hydraulic cylinder was designed. The left side of the product was formed by slider S5， and a local round hole was formed by the tunnel slider S6， which was located in the main slider S5. When the mold was opened， the core?pulling delay was caused by the gap between the holes of the slider angle pin in the slider S5. After the core?pulling action was completed by the spring?driven slider S6， the slider S5 starts to move. The sequential structure of the spring+slider angle pin simplified the secondary core?pulling mechanism. Finally， a single parting hot runner injection mold was designed with a longitudinal layout of one mold and two cavities， a latent gate feeding， and an oblique pushing out. The lateral movement of all the sliders was completed by a single opening of the mold. The mold has a simple structure with a good stability in operation and a high degree of automation.
Review
SONG Kunpeng, WANG Yinjie, LIU Jiping, FANG Zhuqing, YANG Weiwei, ZHENG Dongsen
Abstract (
1388 )
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1494
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The paper briefly introduced the applications of phosphazene derivatives in the field of flame retardant polymeric materials in recent years， focusing on their effects on the thermal stability and flame?retardant performance of epoxy resin， polyurethane， polyester and polycarbonate/acrylonitrile-butadiene-styrene alloys. The possible flame-retardant mechanisms were discussed， and the development direction of phosphazene-based flame retardants was prospected.
HE Jingxiu, CHEN Yajun
Abstract (
1588 )
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1573
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48 )
This paper reviewed the recent research progress in the flame-retardant modification technologies of bio-based flame retardants with respect to its application in green flame-retardant PLA. The recent progress in flame retardant PLA containing bio-based flame retardants was especially analyzed and summarized. These bio-based flame retardants covered cellulose， lignin， chitosan， phytic acid， cyclodextrin and starch. Moreover，the present problems in the applications and development of bio?based flame retardants were discussed. Finally， the development trend of bio?based flame retardants in flame-retardant PLA was prospected.
WANG Conglong, ZHANG Yihui, WANG Xiangdong, XU Haiyun
Abstract (
977 )
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1229
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This paper introduced the preparation technologies of high-performance polyethersulfone （PES） and polyetherimide （PEI） foams. The influences of preparation technology， processing conditions， nano-fillers and blends on the structure and properties of the foams were discussed. The similarity and difference between the PES and PEI foams in their applications and foaming behaviors were also presented.
