LI Xiaoyan, DING Fuchuan, ZHANG Heqiang, XIE Meixia, WANG Shengquan, LI Jiao
Abstract (
795 )
PDF (1041 KB)(
458
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Montmorillonite（MMT）was surface-treated with γ-glycidoxypropyltrimethoxysilane (KH560) as a modifier, and then the surface-modified MMT was blended with vinyl acetate ethylene copolymer (VAE) emulsion to prepare a type of nanocomposite barrier coating. The structure of pristine MMT and surface-modified MMT were characterized by FTIR and XRD, and the microstructure, thermal stability, mechanical and barrier properties of MMT/VAE nanocomposite coatings were further evaluated by SEM, XRD, TG, DSC, the penetration experiments of water vapor and oxygen, and tensile experiments. The results indicated that KH560 was successfully grafted onto the surface of MMT, thus resulting in an increase of interlaminar spacing of MMT from 1.210 nm to 1.447 nm. The modified MMT was uniformly distributed in the VAE matrix, and the interlaminar spacing of MMT was further improved to 2.758 nm. The thermal stability of the nanocomposite coatings was also improved with an increase of MMT. After the PET thin film was coated with the nanocomposite coatings containing 50 wt % of surface-modified MMT, the water vapor and oxygen transmission rates of the thin film decreased by 81.79 % and 95.3 % respectively, and their yield strength increased by 52.68 %. Moreover, the thin films achieved an increase of elastic modulus by 74.16 % for the nanocomposite coatings containing 30 wt % of surface-modified MMT.
LIU Yichun, TIAN Yaozhu, SUN Xin, LU Zhiyang
Abstract (
643 )
PDF (1154 KB)(
312
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The ionic liquid was combined with a starch-based antistatic agent for use in antistatic modification of PE-HD, and the effect of two additives on the antistatic effect and mechanical properties of PE-HD-based compounds were investigated. The results indicated that a combination of ionic liquid and starch-based antistatic agent generated a good antistatic effect and long-term durability on the PE-HD compounds, and there was no reduction of tensile strength and notched impact strength found in the PE-HD compounds at a certain amount of ionic liquid and starch-based antistatic agent.
KANG Wei, LIU Xijun, WANG Yuwei, SHEN Luyan, HAN Xianxin
Abstract (
972 )
PDF (1589 KB)(
409
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PMMA/graphene nanocomposites were prepared via emulsion polymerization by using dimethylaminoethyl methacrylate (DMAEMA) as a reactive dispersant which can help graphene nanosheets to be well dispersed in MMA monomer, and their structure and properties were analyzed and characterized by Fourier-transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, differential scanning calorimetry, thermogravimetric analysis, electronic universal testing machine, impact test machine and high resistance meter. The results indicated that the graphene nanosheets were encapsulated by PMMA with the aid of DMAEMA due to a strong interaction between the graphene nanosheets and DMAEMA derived from their surface functional groups. The introduction of graphene nanosheets improved the thermal stability of the nanocomposite, leading to an increase in Tg by 6.4 ℃ and in Tonset by 38.3 ℃. The addition of graphene nanosheets also enhanced the antistatic property and tensile strength of the nanocomposites but reduced their impact strength slightly.
YI Xin, ZHOU Hualong, ZHANG Yong, JIANG Xing, YAN Dingxiang
Abstract (
605 )
PDF (2893 KB)(
276
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A series of polyethylene (PE-HD)/ultrahigh-molecular-weight polyethylene (PE-UHMW)/graphite-carbon nanotubes (G-CNTs) composite materials with a segregated structure were fabricated by means of a solution-mechanical mixing and hot-compression method. In such a segregated structure, the G-CNTs hybrid was distributed in the PE-HD matrix to form a conductive PE-HD/G-CNT layer, which could be selectively localized on the boundary of PE-UHMW granules. The resultant composite exhibited excellent electrical and mechanical properties. The segregated structure endowed the composite with a very low percolation threshold of 0.23 vol % at the graphite/CNTs weight ratio=1/3. The composite containing only 4 wt % of filler achieved an electrical conductivity of 0.92 S/m, and its tensile strength, Young's modulus, and elongation at break reached 27.1 MPa, 758.5 MPa and 138.7 %, respectively. Additionally, the electrical and mechanical performance of the composites could be controlled by adjusting the weight ratio of low-cost graphite and highly conductive CNTs. This is of greatly significant for the practical applications.
HAN Shuo, WANG Xiangdong, CHEN Shihong, JIANG Can, WANG Yaqiao
Abstract (
804 )
PDF (2469 KB)(
307
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PET/PA6 blends were prepared by melt blending with an epoxy-based chain extender, and their crystallization characteristics, rheological properties and phase structures at different addition levels of epoxy-based chain extender were investigated by DSC, rotary rheometer and SEM. The results indicated that the combination of PA6 and epoxy-based chain extender improved the crystallization temperature and crystallization rate of PET domain significantly. Meanwhile, the incorporation of epoxy-based chain extender also enhanced the comprehensive performance of the blends due to the improvement of the compatibility between the PET and PA6 phases.
YANG Siqiao, LI Haichao
Abstract (
685 )
PDF (2212 KB)(
235
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Chitin/Gelatin composite membranes were prepared by a blending method, and their morphology, tensile properties, water adsorption, water vapor permeability coefficient and water solubility and water loss rate were investigated extensively. The result indicated that the tensile strength of the composite membranes was greatly affected by temperature. The composite membranes achieved the tensile strength of 77.34~44.44 MPa and the elongation at break of 13.35 %~2.75 % at 35 ℃, whereas they obtained the tensile strength of 6.06~4.75 MPa and the elongation at break of 111.4 %~64.2 % at 5 ℃. This result indicated that a high temperature facilitated to gain the high tensile strength and a low temperature favored the high elongation at break. The composite membranes showed an increase in water vapor permeability coefficient with an improvement of temperature. Moreover, the increase of chitin content resulted in a decrease of water content in the composite membranes.
WANG Minghao, WEI Shiyi, JIA Shuya, HAN Xiaolong, ZHOU Hongfu, WANG Xiangdong, YE Zhiyin
Abstract (
786 )
PDF (2232 KB)(
298
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Poly(vinylidene fluoride) (PVDF)/poly(N-vinyl pyrrolidone) (PVP) blends were prepared by a melt-blending method, and their crystallization and melting behaviors were investigated intensively. The results indicated that the crystallization temperature of PVDF domain decreased from 137.3 to 120.8 ℃ with an increase of PVP content, its crystallinity decreased from 39.5 % to 32.1 %, and its melting temperature was found to decrease slightly. The PVDF/PVP blends were further foamed using supercritical carbon dioxide as a physical foaming agent in autoclave. The investigation on forming performance demonstrated that the cell size and volume expansion ratio of the PVDF/PVP foams increased gradually with increasing the content of PVP and foaming temperature, and their cell density decreased slightly. Moreover, the cell size and cell density of the foams decreased with an increase of foaming pressure, but their volume expansion ratio was improved gradually.
HE Shentao, XU Zhenzhen, ZHANG Chaohui
Abstract (
839 )
PDF (1156 KB)(
330
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In this study, a series of esterified starches with different degrees of modification with succinic acid were prepared, and then the succinate starch/PVA blend films were prepared by a solution-mixing method. The structures of the blend films were investigated by X-ray diffraction, their surface morphologies were observed by SEM, and their mechanical properties were also evaluated. The results indicated that the mechanical properties of the blend films were influenced by the degree of modification with succinic acid, the molecular structure of PVA and the mass ratio of succinate starch/PVA. The blend films were found to exhibit an improvement in breaking strength and elongation at break with an increase of modification degree, and the breaking strength and elongation at break increased with increasing the polymerization degree of PVA and alcoholysis degree. The breaking strength of the blend films tended to decrease at first and then to increase with an increase of starch content, and it reached a minimum at the starch succinate/PVA mass ratio of 50/50. However, the elongation at break was observed to keep a gradual decreasing trend.
LI Meilan, GONG Wei, SHI Jing, XU Jiao, KE Xiu, LIU Bailing
Abstract (
578 )
PDF (1839 KB)(
243
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In order to obtain the technical basis of the amphoteric PVAc copolymer emulsion used in ecological sand-fixing of salty desert, a detailed investigation was conducted for illuminating both the sand-fixing properties and ecological effect of the amphoteric PVAc copolymer emulsion. The experimental results showed that the amphoteric PVAc copolymer not only had excellent salt resistance, but also the sand-fixing strength of the amphoteric PVAc copolymer emulsion reached 0.46 MPa when the used concentration was 2% for sand-fixation in high salt-affected sandy land, which had met the requirements of wind erosion resistance in desert environment. In addition, compared with non-amphoteric PVAc copolymer emulsion, the amphoteric PVAc copolymer emulsion could significantly improve the water-retention property and increase the utilization rate of water, thus it could promote the growth of sandy soil microorganisms. These experimental results showed that the amphoteric PVAc copolymer emulsion could be used as a novel ecological sand-fixing material for the ecological management of salty desert.
FANG Shengjie, BI Chao
Abstract (
542 )
PDF (1082 KB)(
397
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In this work, the relationship between the process factors of a small-scale single-screw extruder for consumable filaments and the diameter of 3D printing consumable filaments was analyzed, and then a BP neural network-based prediction model was established by setting the die temperatures of three zones, barrel temperature, screw speed and tractor speed of single-screw extruder as input variables and the filament diameter as an output variable. The more accurate results could be obtained from this BP neural network prediction model, indicating a good prediction capability. Based on the network model developed by this work, the prediction software was designed and developed for application in the production line of consumable filaments, and this software could provide a high-efficient and rational guidance for determining the processing technology.
ZHANG Lei, CAO Yuguang, SONG Ming, XU Guoqiang
Abstract (
741 )
PDF (2155 KB)(
392
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The load-displacement curve, mechanical parameters and fracture morphology of polypropylene twisted cables and plaited cables during tension were obtained by means of an electronic universal testing machine, a VIC-3D non-contact full-field strain testing system and a digital camera. The mechanical properties of different structural cables were compared and studied by numerical simulation. The results indicated that the test results were basically in agreement with the numerical simulation ones. The twisted cables deformation and stress distribution were uniform, and the cross-braided part of plaited cables showed obvious deformation with a staggered stress distribution. The equivalent stress of the whole structure decreased due to the superposition of the axial stress and shear stress of the cable during the process of axial tension. The outer layer of the strand is found to break neatly under the action of the axial stress, and the fracture surface of inner layer looks rough under the superposition of axial stress and shear stress.
NI Taotao, JIANG Chen, WANG Haoyang, WANG Zheng, JIAO Hongwen, LIU Wenbin
Abstract (
787 )
PDF (821 KB)(
208
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In this work, we established a method for determination of hexabromocyclododecane (HBCD) in foamed polystyrene (EPS) packaging materials by gas chromatography-mass spectrometry and investigated the content of HBCD in EPS packaging materials. The results indicated that 3.9 % of the samples were found to contain HBCD, and for 11.27 % of the samples, HBCD were intentionally added to meet the requirement for the flame retardancy of materials. In the product market of EPS packaging materials, there was some certain proportion of packaging materials involved the HBCD added deliberately or contaminated. The use of packaging materials is a key factor in determining the addition level of HBCD. Owing to the high requirement for flame retardancy in electronic packaging materials, the addition level of HBCD was as high as 44.4 %, and however, the intentional addition of HBCD was found in filler materials. Because there were insufficient awareness and supervision from the enterprises and local management departments about the prohibition of HBCD in packaging materials, it is highly recommended to enhance the propaganda and supervision of the prohibition of HBCD in EPS packaging materials and promote the use of alternatives for HBCD.
HUANG Ke, YIN Chunyun, LIU Jiang, GAO Jianguo
Abstract (
632 )
PDF (1848 KB)(
403
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A 3D model for window interior decoration was analyzed to determine the position of hot runner gate by the NX12.0 software, and the die surface temperature, melt temperature, ejection temperature and cooling time were selected as research objects. The mold surface temperature was determined as 60 ℃, the melt temperature as 260 ℃, the ejection temperature as 82 ℃, and the cooling time was determined as 30 s by means of the orthogonal test and extreme difference analysis method. A minimal warping rate of 1.45 % was achieved for the window interior trim. The group parameters of K3H3J2I3 were tested and verified. The test results indicated that the appearance quality of the window interior trim was fine, and there was no warpage phenomenon observed. This proved the accuracy of Moldflow 2018 finite element analysis data and the rationality of extreme difference analysis method.
YU Jing, LI Minxian, GUO Qiangqiang, CHEN Wei, JIA Xianfeng, ZHANG Ning
Abstract (
900 )
PDF (895 KB)(
592
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A calcium/zinc benzoate-castor oleate liquid thermal stabilizer was synthesized by using benzoic acid, castor oleic acid, zinc oxide and calcium hydroxide as raw materials and then combined with some auxiliary thermal stabilizers such as beta-dione, triphenyl phosphite and pentaerythritol. The effects of Ca/Zn ratio and the amount of auxiliary thermal stabilizers on the properties of the stabilized products were investigated. The static thermal stability was measured by a Congo red test, and the dynamic thermal stability was characterized by a torque rheometer and a twin-roll mill. The PVC samples stabilized with thermal stabilizers were also analyzed by a thermogravimetric analyzer. The results indicated that the stabilized PVC samples exhibited an optimal thermal stability at a Ca/Zn mass ratio of 3/1, a beta-dione dosage of 0.75 g, a triphenyl phosphite dosage of 10 g and a pentaerythritol dosage of 1 g. Meanwhile, their dynamic thermal and the equilibrium torque stability reached 1 180 s and 21 N·m, respectively.
GU Xiaohua, LYU Shiwei, ZHANG Xiaohua, LUO Hongxiang
Abstract (
635 )
PDF (785 KB)(
393
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Polyol could be obtained from degradation of waste polyurethane (PU) foam and then mixed with polyether, a catalyst and a foam stabilizer to form a series of oligomers. Subsequently, these oligomers could be mixed with isocyanate to prepare a type of recycled rigid polyurethane foam for reuse. In this paper, we investigated the effect of addition amounts of two-component small molecule alcohol on the degraded material and the effect of additives on the strength of the rigid PU foam. The morphology, viscosity, strength, water absorption and thermal stability of the PU foam were investigated by polarizing light microscopy, FTIR, TGA. The results indicated that the optimum process condition for preparation of the rigid PU foam was determined as the polyether polyol 4110/ethylene glycol weight ratio of 50/30, and the resultant PU form achieved the compressive strength of 133.3 kPa, a water absorption of 0.552 5 %, a thermal conductivity of 0.015 19 W/(m·K) and a density of 37 kg/cm3. The rigid PU foam developed by this work presented the comprehensive performance in accord with the national standards.
HUANG Zhuozhi, XU Hong, MAO Xin
Abstract (
825 )
PDF (979 KB)(
484
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This paper established a methodology for determining the content of acetaldehyde in the bottled water in PET bottles by automatic headspace-trap gas chromatography. This methodology includes the following steps: 10 mL of water sample was taken and then 4 g of sodium chloride was added into the sample. The sample was enriched by trap to improve sensitivity for gas chromatographic analysis. The temperature of headspace oven was set as 80 ℃, the needle temperature as 130 ℃, the transmission line temperature as 135 ℃, the balance time of oven as 20 min, the trap adsorption temperature as 30 ℃, the desorption temperature as 280 ℃, the cycle number as 3 times, the GC injection temperature as 200 ℃, and the FID temperature was set as 200 ℃. Moreover, the HP-INNOWAX column was used with the programmed temperature elevation in the temperature range of 50~100 ℃. Moreover, the linearity range was kept within 50 μg/L with a detection limit of 5 μg/L, and the recovery and precision were tested at two concentration levels of 20 μg/L and 50 μg/L. The average recovery was measured to be 92.9 % and RSD values were determined as 2.08 %~4.01 % with a correlation coefficient of 6. This method is simple, rapid, sensitive and reproducible and can be used for the determination of acetaldehyde in the bottled water.
FENG Jing, ZHANG Weihe, DENG Chenglin
Abstract (
665 )
PDF (3695 KB)(
539
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The demolding mechanism with a mode of push rod plus inclined top plus push block plus cylinder ejection was adopted to solve the demolding difficulty in large plastic parts. A lateral core-pulling mechanism with an indirect core-pulling cylinder was adopted for the die, which greatly reduced the maximum shape size of the die and solved the core-pulling difficulty in tunnels. The problem that the instrument panel storage bins of automobile were easy to stick to the die were successfully solved by designing reinforcing ribs and inverted ribs on the moving die side. The dimensional accuracy of plastic parts was greatly improved by adopting the temperature control system of the crisscross “straight-through water pipe plus diaphragm well”. Moreover, the forming cycle reached 50 s, which was lower than that of the same type of instrument panel storage bins by about 10 %.
LIU Xin, GUO Hengya, HUANG Ming
Abstract (
698 )
PDF (1305 KB)(
707
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There is inclined wear occurring in the traditional movable mould with a vertically rotating bicolor injection mould structure due to the dead weight of mould, leading to the malfunction of the mould. Aiming at this problem, a horizontal rotating disk bicolor injection mould was designed. a bicolor hot runner plastic mould was designed by analyzing the structure characteristics of products and the molding process of automobile windshield decorative strip. Furthermore, a core-pulling mechanism with inclined wedge spring side was designed by combining with the structure characteristics of the bicolor mould. Such a design relied on the gap on the inclined guide pillar to realize no action of the side core-pulling for the hard rubber injection and immediate action of the side core-pulling for the soft rubber injection, and therefore the high dimension accuracy for products was ensured. Based on the practical production with this opposite-type injection mould, the structural design of this mould was reasonable to meet the requirements for production process and obtain better economic benefits accordingly.
China Synthetic Resin Supply and Sale Association
Abstract (
656 )
PDF (675 KB)(
525
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This paper introduced the current situation of polycarbonate industry in China, which dealt with the production capacity, self-supply ability, sales situation, applications and existing problems, etc. Moreover, some suggestions for the development of polycarbonate industry in China were proposed.
QIU Yao, FENG Wei, XU Jianzhe, ZHANG Zhenyu, ZHANG Yang
Abstract (
675 )
PDF (3266 KB)(
463
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This paper reviewed the recent research progress in PANI-based composites, which includes the preparation strategies, electromagnetic consumption characteristics and loss mechanisms. Moreover, the future development of PANI-based composites was prospected.
JIA Yuan, ZHANG Peng, LIU Zhen, HAN Min
Abstract (
788 )
PDF (1139 KB)(
756
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This paper introduced the development of flame-retardant polymer materials and reviewed the research process in the preparation of flame-retardant polymer materials, including intramolecular hybrid flame-retardant polymers and additive-type flame retardant polymers. Meanwhile, the application ranges of flame-retardant polymers were summarized and their future research direction was also prospected.
YANG Bo, LIU Yijiang, LI Maodong, ZHAI Wei, LUO Wenbo, WANG Zhigang
Abstract (
536 )
PDF (1789 KB)(
530
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This paper introduced the theoretical background and experimental methods of cyclic cracked round bar (CRB) test and also reviewed the research status at home and abroad for the cyclic CRB test method applied in the characterization of slow crack growth resistant performance of polyethylene pipes. In addition, the applications and development direction of CRB test was discussed.
