Materials and Properties
MA Haopeng, GAO Lijie, JIAO Zhiwei, MA Jubiao, YANG Weimin∗
Abstract (
830 )
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This article investigated the feasibility of a non-solvent induced phase separation technology for 3D printing/copying forming. With this technology， the three-dimensional polyacrylonitrile products were successfully prepared without any molten materials. Based on the experimental results， the forming process route was determined as follows： the non-solvent induced phase separation method was first used to solidify the product and remove the solvent initially； the resultant product was then heated and evaporated to completely remove the internal solvent. The reduction of water content of the environmental solution could help to improve the size uniformity of the inner hole in the resulting product， reducing the hole size and leading to a more uniform hole distribution. In addition， we investigated the application possibility of this technology for the preparation of high-performance ceramic composites， conductive products and catalyst carriers as well as the application prospects of this forming technology.
DING Jianfeng, WANG Wei, LIU Yao, XIA Zhean, LI Xinxin∗
Abstract (
704 )
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400
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5 )
Three types of inorganic nucleating agents， potassium titanate whisker （PTW）， Kaolin and talc， were used to prepare the PA6/carbon fiber （CF）/NA ternary composites， and their mechanical properties， dynamic mechanical properties， morphology， crystalline structure， thermal stability， non-isothermal crystallization and melting behaviors were investigated. The results indicated that the inorganic nucleating agents had little influence on the mechanical properties of the PA6/CF composites. Nevertheless， the addition of talc could greatly improve the impact properties of the composites， and their impact strength increases by 44.5 % with the addition of 2 wt% talc. Scanning electron microscopic observation showed that there were lots of fibers pulled out of the composites， and the exfoliated talc platelets were homogeneously dispersed in the PA6 matrix. Non-isothermal crystallization analysis indicated that there was a nucleating effect from these three nucleating agents， in which talc exhibited the best nucleating performance. The heterogeneous nucleation of talc could significantly improve the crystallization temperature of the composites and promoted the PA6 matrix to form a more perfect crystalline structure.
GUO Haoran, CHEN Yunzhi∗, WANG Jiaoyang, ZHANG Zhengjian, SUN Lingze
Abstract (
748 )
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323
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Xylan was modified with a silane coupling agent， KH560， and then used to prepared the poly（butylene adipate-co-terephthalate） （PBAT）/poly（lactic acid） （PLA）/xylan composite films through melt blending. The effect of the content of the modified xylan on the mechanical properties， oxygen permeability， moisture permeability and light transmission of the composite films was investigated. The results indicated that the composite films achieved optimum tensile strength and oxygen transmission rate at a xylan content of 1 wt%. The tensile strength of the composite films increased by 11.7 % compared to that of pristine PBAT/PLA film， while their oxygen transmission rate was also higher than that of the pristine one. However， their oxygen transmission coefficient was reduced by 32.7 %. The moisture resistance of the composite films with the modified xylan was significantly higher than that of the unmodified one. Moreover， the haze of the composite films increased with an increase in the xylan content.
MA Yuji, FANG Mei, LI Guixun, HUANG Ming, LIU Chuntai, ZHANG Na∗
Abstract (
1421 )
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699
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In this paper， four types of PVB sandwich films for automotive front shield glass were tested as model samples， and their thickness， water content， tensile property and surface texture were investigated. The results indicated that the sandwich films with good thickness stability and low moisture content had higher tensile strength and elongation at break. This is of great significance for improving the crash?resistance and energy-absorbing protection of the glass. Surface topographical study showed that the sandwich films presented a more uniform texture distribution at good thickness stability.
LI Jun, MA Wenbo, ZHANG Zehui, TIAN Hao, PENG Yuying
Abstract (
815 )
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374
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The conductive composites based on polypropylene （PP）， polycaprolactone （PCL）， graphite and carbon nanotubes （CNTs） were prepared by melt blending， and their microstructure， melting flow rate， mechanical properties， electrical conductivity， electro-thermal performance， and thermal stability were characterized. The results indicated that the fracture strength of PP increased by 4.375 MPa with the addition of PCL. However， its mechanical properties decreased by 73.5 % when graphite and CNTs were further added. The incorporation of graphite and CNTs effectively reduced the resistivity of PP， leading to a transition from insulator to semiconductor with a resistivity of 7.83 × 106 Ω·m. According to the thermogravimetry analysis， the introduction of PCL significantly improved the thermal stability of PP， resulting in an increase in initial decomposition temperature from 368.88 °C to 398.95 °C. Its initial decomposition temperature further increased to 408.78 °C with the addition of graphite and CNTs.
DONG Dongdong, WANG Gang∗, SU Xiaofeng, WANG Chong, ZHANG Nan
Abstract (
783 )
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577
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Taking ammonium metavanadate， polyethylene glycerin， cetyltrimethylammonium bromide， sodium pyrophosphate decahydrate and polyvinylpyrrolidone as shape control agents， five kinds of calcium carbonate particles with different shapes including flake， diamond， rod， ball and cube were prepared by a carbonation method using calcium chloride and sodium carbonate as raw materials. The effect of the morphology of calcium carbonate particles on the mechanical properties of soft PVC films was investigated. The results indicated that the mechanical properties of the films were improved with the addition of calcium carbonate at different morphologies， and their tensile strength and elongation at break increased significantly. The calcium carbonate with a rod morphology led to optimum mechanical performance for the PVC films， and the films achieved the tensile strength of 27.11 MPa. The films obtained a maximum value of 98.23 % in elongation at break in the presence of calcium carbonate with a diamond shape.
LI Zhihong, JIANG Lu∗, YU lei, LI Peng
2020, 34 (12):
41-46;
Abstract (
502 )
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315
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In view of the gas polyethylene pipe manufacturing under the supervision of inspection organization，the factors of pipe failure in manufacturing process were analyzed by means of the FMEA. The manufacturing process was divided into 5 parts and 10 risk points，and 20 failure modes were identified. The scale of the degree of possibility，severity and detection were given to obtain the RPN. The risk control measures of each risk point were provided in combination with the working experience. Most of the RPN of failure modes are similar to each other. Only the RPN is higher than others under the failure mode of improperly adjusted process parameters.
Processing and Application
XIANG Guanghui , YU Wenji
Abstract (
628 )
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526
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The effects of the moisture content and the plasticizer absorption rate on the devolatilization efficiency of cellulose diacetate were investigated， and the influences from the screw speed， feeding amount and screw configuration were also analyzed. The results indicated that water as a devolatilization promoter facilitated devolatilization. High plasticizer absorption was disadvantage for devolatilization. However， high screw speed， low feed rate and the use of high-barrier threaded element in front of the exhaust port were advantageous for devolatilization. The devolatilization can improve the transparency and heat stability of the products of cellulose diacetate. The composition analysis indicated that more than 60 % of volatiles were diethyl phthalate. The condensation system was designed to perform the separation of plasticizer from volatiles， realizing the recovery and utilization of diethyl phthalate.
WANG Jing , ZHOU Laishui , LI Peng, BI Jianping , LIU Jun
Abstract (
577 )
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381
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The current research status of the design technology of parting molds was analyzed by combination of the practical knowledge and experience of the parting mold design of injection mold. Aiming at the shortcomings of the current parting mold design system and the actual needs of manufactures， an automatic recognition algorithm for the parting line of the mold and an automatic generation algorithm for the specific blocks of the mold were proposed. Based on the NX platform， an automatic parting mold design system was developed. This system is not only easy to operate but also can reduce the dependence on the experience and knowledge of designers. The obtained example indicated that this system had high practicability and could greatly improve the design efficiency.
WEI Chenjie , WANG Jifen , FAN Linyuan, MU Yilong, DU Haoyu
Abstract (
482 )
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280
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Aiming at the requirement for fast， nondestructive and accurate inspection， a spectral data fusion technology based on infrared spectrum original data and derivative data was adopted to analyze a series of automobile lampshade samples. The infrared spectra were obtained and collected from 44 lampshade samples. The automatic baseline correction， peak area normalization and Savitzky?Golay algorithm were used to preprocess the infrared spectra， and the first derivative was carried out for the processed data. The classification model was constructed by an artificial neural network algorithm. In the radial basis function neural network model， the original spectral data， first?order derivative data and fused data were classified as combined with the principal component analysis， and their classification accuracies reached 81.2 %， 84.1 % and 90.9 %， respectively. In the multi?layer perceptron neural network model， the original spectral data， first?order derivative data and fused data were classified with the classification accuracies of 84.1 %， 86.4 % and 97.7 %， respectively. In addition， the classification accuracy for 12 brands in 44 lampshade samples also reached 97.7 %， indicating an ideal experimental result. The research results indicated that the spectral data fusion technology based on the infrared spectrum original data and derivative data could realize an accurate analysis for the automobile lampshade samples and therefore meet the requirements for fast， nondestructive and accurate inspection. This work provides a good reference for the examination of physical evidence in the field of forensic science.
Additive
Changlong CHI, Yanfei AN, Yaru YAN, Xiang YU
Abstract (
543 )
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481
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PA12 powders were prepared by a solvent precipitation method at different contents of ethanol and additives, and their properties were investigated. The results indicated that the content of ethanol and additives were highly related to the performance of PA12 powders. The average particle size of PA12 powders decreased at first and then tended to increase with an increase in the ethanol concentration. Moreover， the particle size distribution of PA12 powders became more uniform， and their flow rate and density increased and decreased， respectively， as a result of the increase of ethanol concentration. With an increase in the content of SiO2 as an additive， PA12 powders presented an increased flow rate and the uniformity of particle size distribution， and however their average particle size and density decreased at first and then tended to increase.
Standard and Test
Yingxin ZHOU, Yunxuan WENG, Zhigang HUANG, Lei WANG, Xiaoqian DIAO, Xinyu SONG
Abstract (
718 )
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664
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This paper introduced the relevant regulations， standards， supervision and management system of the food contact plastic materials and products in China， and also analyzed the current status of laws， regulations and standards for the food contact plastic materials and products in major developed countries such as the United States， the European Union and Japan. By means of a comparative analysis method， the similarities and differences in Chinese relevant laws and standard systems are compared in terms of raw material resins， molded products and test methods. This paper can provide more information and references for relevant enterprises and inspection institutions， and strengthen the understanding and research of relevant policies and regulations， improving the quality of food contact plastic materials and products in China.
JIANG Hong, ZHAO Yanhua, ZHU Xiaohan, YUAN Zhihao, XU Shaohui, LI Chunyu
Abstract (
462 )
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267
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In order to establish a method to test the material evidence of plastic steel windows， 40 different brands， different series of the same brand， and different batches of the same brand and the same series of plastic steel windows were inspected by X-ray fluorescence spectrometer. The Niton XL3t GOLDD+ hand-held fluorescence spectrometer was used to determine the detection conditions： Ag as anode target； detection voltage： 50kV； detection current： 200μA； acquisition time： 70s. Under these conditions， samples can be detected according to the type and mass fraction of characteristic elements measured by different plastic steel window samples. In order to make the classification results scientific and accurate， the principal component analysis method was used to reduce the dimension of the experimental results， and four factors were designated and extracted. Then， the sample data were clustered by using the hierarchical clustering and K-means fast clustering methods. 40 samples were divided into 28 categories， and Fisher discriminant analysis was used to verify the scientific rationality of the classification results. Combined with spectrogram analysis and chemometrics， this method can classify samples quickly， accurately and non destructively， and provide help for the police grassroots to handle cases.
Machinery and Mould
TIAN Ke
Abstract (
510 )
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481
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This paper reported an introduction for a special single-color and bi-color integrated family two-plate injection mold. The layout of the mold was composed of 1 mold and 2 cavities. One cavity was used for monochromatic injection molding of plastic parts， and another was used for monochromatic injection molding of plastic parts. A combination of single?cavity and bi-color mold cavity can realize the bi-color injection molding of plastic parts with only one mold cavity. This function can be realized through changing the shape and position of the cavity insert and the position of the second rubber gate molding part on the basis of the single-color mold cavity. In this case， the purpose of single cavity and bi-color injection molding can be achieved. Combining with the transformation of the gating system， this mold can realize five injection molding functions， including the single-cavity injection function of single-color plastic parts， the double cavity injection function of single-color plastic parts， the double cavity injection function of single-color plastic parts， the single-color plus bi-color family injection function， and the injection of two different colors of the same plastic parts in single mold. The mold structure is novel， simple and practical. Such a design can effectively reduce the manufacturing cost of injection molding parts with multiple requirements and therefore provides a reference for the design other molds.
LIU Qingdong
Abstract (
538 )
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489
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Taking an electroplated plastic decoration strip in the Jaguar car as a research object， this paper reported a design for the injection mold of the decoration strip with a twisted U shape. According to the structure of the decoration strip，the gating system with hot runners transferring to the cold ones was designed. In the traditional submarine gate， plastic powders are easy to emerge when the runner setting is ejected. To address this problem， a new submarine gate under a lifter was designed. In order to deal with the problem of over?plating to the end of the plastic part， an arc?shaped runner was designed. In addition， a four-side tilting slide was designed on the basis of the structure of the plastic par. The result indicated that this structure was reasonable， reliable and could meet the requirement for practical production.
Review
LI Chenyang, GONG Weiguang, MENG Xin, CAO Qiming, YAO Zhongyang
Abstract (
673 )
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587
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Antioxidants play an important role in preventing the oxidation of polyolefin materials. However， they are easy to migrate and volatilize， resulting in a reduction in antioxidation efficiency. Therefore， it is of great significance to improve the anti-migration of antioxidant. This paper introduced the recent research progress in antioxidant migration resistance through macro?molecularization， polymer encapsulation and inorganic particle immobilization. Furthermore， the existing problems and improvement methods of current antioxidant migration resistance technology were proposed， and the its development trend in future was prospected.
ZHANG Yunqing
Abstract (
551 )
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414
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6 )
This paper reviewed the development evolution of fiber orientation model and also introduced the basic theoretical ideas and expressions based on the engineering applications of the fiber orientation model for long-fiber-reinforced thermoplastics （LFRTs）. The fiber orientation model was derived from the Folgar-Tucker model and then developed to an anisotropic fiber orientation and a retarding rotary evolution. Finally the ARD-RSC model and iARD-RPR model were formed to predict the fiber orientation of LFRTs. Based on the CT scanning results of the fiber orientation in the injection molded spline of long?glass?fiber?reinforced polypropylene， the prediction accuracy of the two models was studied.
JIA Xuan, FU Chenxing, ZHANG Junping, LI Mingxiao, LI Xueqi, LIU Xiaopei
Abstract (
1250 )
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644
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35 )
As a completely biodegradable agricultural mulching material， degradable liquid mulching films are considered as a type of agricultural films in accordance with the new development trend. This paper systematically summarized the types， characteristics and performance of degradable liquid mulching films， and also analyzed the representative technology and preparation mechanism of natural polymer material liquid mulching films on the basis of the grafting copolymerization mechanism. Moreover， the application status and effects of representative liquid mulching film materials at home and abroad were evaluated. Furthermore， some opinions were proposed to address difficulties in the development of current liquid mulching film materials， providing a technical support for the exploitation of new liquid mulching film materials and their performance enhancement.
