Interview
Forum
ZANG Xiaoling, WEN Bianying
Abstract (
3573 )
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2346
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299 )
This article summarizes the development of green manufacturing and the whole life cycle of polymer materials from multiple aspects such as the source of raw materials， i.e. monomers， catalysts， synthesis methods， processing technologies， and recycling strategies. The research results demonstrated that there were a variety of natural resources that do not rely on petroleum and can be used to obtain polymer materials. Some new synthesis and processing technologies can help to reduce energy consumption and emissions. The used polymer products can be regenerated and reused through four ways， including physical， chemical， energy and biological cycles. A green and controlled production path throughout the life cycle has become an important and feasible development direction in the future.
ZHANG Yuxia, YANG Tao
Abstract (
1196 )
PDF (2173 KB)(
1108
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49 )
This paper introduced the current situation of plastics packaging industry and policies as well as the regulations for the treatment of plastics packaging waste in China. The respective responsibilities from government， companies and consumers for dealing with plastics packaging waste were analyzed. Some thinkings on the establishment of the systems for sorting， collecting and managing plastics packaging waste were proposed.
REN Zhaofang, LI Dan, PAN Jingjing, ZHONG Huaining, WANG Liang
Abstract (
1677 )
PDF (1113 KB)(
1022
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71 )
As an important starting point and practice in the construction of national ecological civilization， the application of recycled plastics in food contact materials has been recognized as one of the key measures to deal with plastic waste pollution under the background of sustainable development. The management methods of recycled plastics for food contact applications in the European Union and the United States were discussed. The opportunities from the encouragement policies and the development of standardization for the application of recycled plastics as food contact materials were described. At the same time， the challenges such as contaminant migration and meeting the requirements of food safety standards were analyzed systematically. Some suggestions were proposed in view of various perspectives such as legislation， market supervision and safety assessment with the aim to provide references for Chinese government and manufacture enterprises of food contact materials in the application and control of recycled plastics.
DU Huanzheng, LU Sha, SUN Jian, SONG Shuwei
Abstract (
1054 )
PDF (1435 KB)(
1456
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32 )
The development of plastic industry has made great contributions to the improvement of people’s living quality and convenience. However， the environmental pollution caused by improper waste disposal can not be ignored. The critical way to prevent and control the plastic pollution is to use， recycle and reuse plastics properly， which can prevent plastic wastes from leaking into the nature. In this sense， the construction of a high?value plastics recycling system has become the top priority. Traceability becomes the key power to achieve this goal， and the relevant policies and participation become the twin engines to promote the realization of the goal. This paper clarifies the conception of traceability and main traceable approaches， analyzes the domestic and international application scenarios， and points out the difficulties in tracing plastics in China. Based on the above results， some suggestions on the construction of traceability system in China were proposed together with the analysis for the specific elements， promoting its implementation in accordance with the corresponding policies.
Review
SUN Xiaodong, CAO Ding, HU Qianqian, YAO Wenqing, LI Jinghong, FENG Yongjun
Abstract (
2803 )
PDF (2052 KB)(
4945
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116 )
Plastics play an important role in human social progress and economic development. However， the large-scale production and use of plastics will inevitably produce a large amount of waste plastics， which have undoubtedly brought serious pollution to surface water， soil and ocean. Plastic pollution has become a global sustainable development challenge. The traditional physical recovery methods are difficult to meet the requirements of environmental protection and recycling. It is of great importance and urgency to develop efficient chemical recovery and resource utilization. Aiming at 8 types of typical plastics with a large quantity and a wide range of applications including polyethylene terephthalate， polyolefin （including polyethylene and polypropylene）， polyvinyl chloride and polyurethane， this paper summarized the research progress in the chemical recovery and resource utilization of waste plastics at home and abroad， especially the new technologies developed in recent 10 years. This paper can provide a good reference for the development of chemical recycling technologies of waste plastics.
FENG Yuhong, YAO Wenqing, SHANG Chaonan, XIE Yanli, ZHANG Mingnan, ZHOU Xueqing, WANG Guizhen, YU Wenhui, DOU Zhifeng
Abstract (
968 )
PDF (1306 KB)(
1060
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16 )
This paper reviewed and summarized a variety of relevant laws/regulations and inspection/test standards for controlling disposable plastic wastes in China and abroad. The standards related to synthetic biodegradable component or non?biodegradable disposable plastic products， traditional identification standards of non?biodegradable plastic waste recycling plastic， evaluation standard of fully biodegradable plastics， and plastic rapid detection technologies and standards were emphatically introduced. The development of new inspection and test technologies in future was prospected.
LI Mingfeng, CAI Zhiqiang, ZOU Liang, WEI Xiaoli, XI Yuanbing, WANG Guoqing, CAI Lile, ZHANG Zhemin, XIA Guofu, JIANG Haibin
Abstract (
2517 )
PDF (4088 KB)(
8821
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73 )
The chemical recycling of waste plastics is considered to be the only technology that can realize the sustainable development of plastic resources. In particular， the pyrolysis technology has attracted a great deal of attention. Based on the own superiority， Sinopec has carried out a comprehensive design and developed several different methods for the chemical recycling of plastic wastes. A novel technology of Sinopec plastic wastes was developed to produce the low impurity oil （SPWO） through the physical removal of impurities coupling with solvent pyrolysis. It achieved the goal of maximizing the production of low?impurity oils， building up a good basis for the full recycling of waste plastics. A microwave?assisted pyrolysis technology of plastic wastes was developed to produce olefins in one step. The cetane number reached 61.2 for the diesel fraction obtained from the hydrogenation of plastic wastes pyrolysis oil. The gasoline yield reached 50 % when using the catalytic cracking technology to produce gasoline. The gasoline yield reached 30 % and the total yield of ethylene and propylene reached 18 % when using the catalytic cracking technology to produce gasoline and olefin. The hydrogenation?steam cracking technology of plastic wastes pyrolysis oil for olefins was designed and developed， and the olefin （ethylene， propylene and butadiene） yield reached 41.9 %. The carbon footprint analysis of chemical recycling technology routes for different plastic wastes was carried out. Compared to the carbon emissions of the petroleum?based refineries and incineration for power generation technology， the chemical recycling of plastic wastes exhibits good carbon reduction competitiveness.
CAI Yi, TIAN Hui, XIE Miaoxue
Abstract (
1117 )
PDF (1955 KB)(
1269
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25 )
Plastics are widely used as raw materials in the manufacture of household electrical appliances. It is crucial to research how to recycle waste plastics from household electrical appliances with high efficiency and high value. Different plastics have been widely used in household electrical appliances according to their different advantages， presenting a trend of light weight， health and environmental protection. This paper summarized the policies and standards in China and analyzed the current situation of waste plastics recycling technology. With the promotion of an extended producer responsibility system， the intelligent and efficient sorting equipments and composite processing technologies will be adopted in the waste plastics recycling industry of household electrical appliances to improve the value of resource utilization， establish and develop a standardized threshold for the performance of recycled plastics， build and improve the application market of recycled materials， and enhance the recyclability of native plastics through ecological design.
Materials and Properties
LI Pan, LI Dongfeng, LU Xinyan, PENG Qihua, LU Bo, JI Junhui
Abstract (
737 )
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1261
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12 )
A novel type of pavement asphalt polymeric modifier was prepared through mixing recycled polyethylene mulch film residue with poly（vinyl acetate） and petroleum resin. The use of the modifier reduced the crystallinity of PE and improved its low temperature flexibility， impact resistance， high melt flow rate， and adhesive performance with sand inorganic materials. This modifier can be directly mixed and stirred with stone in the mixing plant. Compared to the traditional SBS asphalt modifier， the modifier developed by this work can improve the high and low temperature performance of asphalt mixture， avoid the sulfur dioxide pollution in the SBS vulcanization process， improve the high and low temperature rutting resistance performance of highway， and realize the transformation of low-grade plastic waste to treasure. It is of great significance to promote the sustainable development of the environment and the construction of green traffics.
JIAN Ranran, YANG Weimin, MOHINI Sain
Abstract (
606 )
PDF (3352 KB)(
571
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6 )
Polystyrene composite foams were prepared with a torsion extrusion technology using reclaimed carbon fiber as reinforcement and nucleating agent. The microstructure and morphology of the foams were reconstructed using X?ray Micro?Computed 3D yomograph and scanning electron microscope. The results indicated that a twist spiral flow occurred in the polymer melt during the process of torsion extrusion， which made the fiber disperse uniformly and orient along the flow direction. The mixing and temperature properties of the whole system were improved with the torsion extrusion， and the cell morphology became more uniform. In addition， the quality of the foam was affected by the die temperature. When the die temperature was higher than 180 °C， the surface of the products became uneven and the phenomenon of gas escaping was observed. With the addition of reclaimed carbon fibers， the bubble tended to grow along the fiber direction. However， the bubble nucleation will be inhibited when the fiber content is too high.
JIAO Jiali, YANG Weimin, GAO Xiaodong, SONG Lijian, CHENG Lisheng
Abstract (
807 )
PDF (2814 KB)(
626
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22 )
The high?value recycling of plastics has become a focus of social and economic researches. In this work， a type of polyethylene?based carbon fiber was successfully prepared by means of a graphene?templating method through the conversion of organic and inorganic materials using low?cost recycled polyethylene. Molecular dynamics simulation was also conducted to analyze the preparation mechanism of the graphene?templating method. The graphene template can promote the growth of the six?membered ring?layered structure of carbon fiber. This is beneficial to the carbonization of polyethylene fibers. Raman spectroscopy and XPS were used to characterize the obtained carbon fiber. The results indicated that the graphene template could facilitate the carbonization of the fiber.
ZHU Daofeng
Abstract (
1034 )
PDF (1398 KB)(
1220
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28 )
The recycled polyethylene terephthalate （rPET） was blended and modified with the original linear low?density polyethylene （PE?LLD） and recycled polyethylene （rPE?HD） by using a self?made graft copolymer compatibilizer， respectively. The rPET/PE alloy sheet （mass ratio of 80∶20） was extruded by a co?rotating twin?screw extruder with drying?free and side?forced feeding system. The performance of rPET/PE alloy sheets with different thicknesses was researched . The results show that the appearance quality of the alloy sheet products prepared by using rPET maintains better. The rPET/PE alloy sheet has good mechanical properties. The tensile strength is greater than 39 MPa， and the elongation at break decreases with the increase of the thickness of the sheet. The tensile strength of 2.5 mm rPET/PE alloy sheet is 39.7 MPa， and the elongation at break is 21 %， and the impact strength is 12 kJ/m2. It is suitable for blister bags， geocells， etc. Drying?free and side forced feeding system can reduce the alloy sheet manufacturing processes， save energy ， and the yield increased 117 %.
GU Xiaohua, LYU Shiwei, LIU Siwen, WANG Jiajia, KANG Yuanyuan
Abstract (
1738 )
PDF (1835 KB)(
1123
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34 )
The two?component alcoholysis agents， ethylene glycol （EG） and propylene glycol （PG）， were used to degrade the waste polyurethane （PU） rigid foams to obtain a degradation product， oligomer polyol. This degradation product was further used together with lignin as raw materials to prepare the composite materials based on the recycled polyurethane （r?PU） rigid foams. The degradation effect of PU products and the compressive strength， water absorption， thermal conductivity， microscopic morphology and stability heat of r?PU composite materials were investigated using thermal conductivity tester， scanning electron microscope， thermogravimetric analyzer， and Fourier?transform infrared spectrometer. The results indicated that the waste PU achieved an optimal degradation effect at a mass ratio of EG to PG of 2∶3 （mEG∶mPG）. The foam cell wall was thick and relatively uniform， and the skeleton geometry was complete. The compressive strength of r?PU composites was 185.3 kPa and its thermal conductivity was 0.0215 W/（m·K）. These data can meet the requirements of national standards.
Processing and Application
ZHA Yan, ZHENG Fangli, XIAO Jian, YANG Weimin, XIE Pengcheng
Abstract (
617 )
PDF (3512 KB)(
434
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27 )
Reduction design is an effective way to realize the effective utilization of plastic product resources and the prevention and control of pollution sources. However， traditional simulation methods cannot accurately express the material properties of composite injection?molded parts. To improve their simulation accuracy， we designed a guide?rail?reduction structure to ensure that the overall stress level is within a safe range according to the fiber orientation and structural stress of the guide and the distribution situation. This design was based on a multi?scale co?simulation method with the timing chain guide rail of an automobile engine as an example. With this design， the maximum stress was reduced by 12 % and the mass was reduced by 4 %. This realizes the reduction design of the timing chain guide rail of the automobile engine.
TANG Yujing, WANG Yaqiao, NI Jingyue, WANG Conglong, WANG Xiangdong
Abstract (
955 )
PDF (3087 KB)(
496
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24 )
This paper focused on the effects of stereoscopic composite （Sc） crystals induced by PDLA on the popularity and foaming behavior of the PLLA/PDLA blends. Polytetrafluoroethylene （PTFE） was introduced into the blends as a synergist. The effect of PTFE on the formation of Sc crystals was investigated， and the rheological and foaming behaviors of the blends were also studied. The results indicated that the content of Sc crystals was significantly increased when 0.5 wt.% PTFE was incorporated. The formation of Sc crystals improved the melt strength， promotes the cell nucleation of the blends. This effectively improved the foaming performance of PLA， resulting in the formation of the micro/nano?sized composite cells.
XUE Yu, YIN Dexian, XIANG Lubing, ZHOU Yuan, YANG Xueyue, ZHOU Hongfu
Abstract (
726 )
PDF (2026 KB)(
409
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6 )
The chain?extended poly（butylene succinate） （CPBS） samples were prepared with different contents of chain extender through a melt blending method. As the content of chain extender increased， the crystallization temperature of PBS increased at first and then tended to decrease slightly. The crystallinity of PBS increased slightly， and its viscoelasticity was also improved. Supercritical CO2 was used as a physical foaming agent to prepare PBS foams at a foaming temperature of 87 °C. The experimental results indicated that the cell size and volume expansion ratio of the forms decreased gradually with an increase in the content of chain extender， but and their cell density increased gradually. A microcellular CPBS foam was successfully prepared at a chain extender content of 8 wt %， leading to a cell size of 9.2 μm and a cell density of 1.93×109 cells/cm3.
LYU Huaixing, QIN Yufei, ZHAN Lu, NIU Yuanhang, XU Zhenming
Abstract (
952 )
PDF (1662 KB)(
497
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22 )
A mixed plastic crushing material obtained from waste refrigerators was sorted to ABS and PS?HI waste plastics by free falling electrostatic separator. The effects of raw material pretreatment and electrostatic separator process on separation efficiency were studied through notched impact strength， tensile strength and separation efficiency. The results indicated that the efficiency of electrostatic separation and the properties of products were improved obviously through controlling the lower moisture content of mixed plastics. The optimal separation efficiency and product performance were achieved at a voltage of electrostatic separation field of 27 kV and a feeding speed if 550 r/min. The highest separation efficiency of ABS and PS?HI along with the best mechanical properties was achieved with electrostatic separator distances of about 200 and 220 mm， respectively.
WANG Fuyu, GUO Jingqiang, ZHANG Yuxia, YANG Tao
Abstract (
1063 )
PDF (2673 KB)(
1466
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45 )
This paper introduced the technologies and solutions for raw material use?reduction in the production of plastics packaging materials， which included the thinning of plastics films and containers， the structure simplification of packaging articles， the reusing and recycling of plastics packaging products and the use of recycled plastics materials as much as possible. The ideas and ways of large?scale using one?component materials in the manufacturing of plastics packaging materials were described.
Additive
LI Xiangyang, YANG Linzhu, ZHAI Guoqiang, GAO Wanqin, WANG Kezhi, LI Xungang
Abstract (
1004 )
PDF (2434 KB)(
932
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22 )
This paper focused on the effect of hydrazide nucleating agent （TMC?300） on the crystallization and properties of poly（butylene succinate） （PBS）. The effect of TMC?300 on the crystallization process， mechanical properties， thermal properties and shrinkage of PBS were investigated with differential scanning calorimeter， polarizing microscope， electron tension universal test machine， digital impact meter and thermal deformation micro?card temperature meter. The results indicated that the crystallization speed and crystallinity of PBS increased with the addition of TMC?300， and its crystal size was reduced significantly. Moreover， the crystallization temperature increased by 4.74 %， and the half?crystal time was shortened to 57 s with a decreased by 71.88 %. The nucleated PBS achieved a flexural modulus of 689.4 MPa， a heat distortion temperature of 89.6 °C and impact strength of 17.75 MPa， which increased by 9.5 %， 5.5 %， and 171.4 % respectively. This indicates a good balance among the rigidity and toughness and heat resistance. Although the shrinkage of PBS increased in the presence of TMC?300， the shrinkage ratio was closer to 1. This is easier to resolve the deformation and warpage problems occurring in PBS.
Standard and Test
DIAO Xiaoqian, WENG Yunxuan, FU Ye, ZHOU Yingxin
Abstract (
1571 )
PDF (1823 KB)(
1857
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73 )
This paper introduced the degradation mechanisms of biodegradable plastics and the evaluation standard test methods of biodegradability. Based on the degradation function of biodegradable plastics and their environmental conditions after abandoned， the suitable application fields of biodegradable plastics and products were analyzed and elaborated in view of the existing problems in the application and development of biodegradable plastics and products. Finally， the applications and development trend of biodegradable plastics were prospected.
ZHOU Yingxin, WENG Yunxuan, ZHANG Caili, DIAO Xiaoqian, SONG Xinyu
Abstract (
1575 )
PDF (1805 KB)(
2828
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HTML (
54 )
This paper briefly introduced the recycling and application status of poly（ethylene terephthalate） （PET） in recent years as well as the relevant standards and regulations at home and abroad. The research progress in the physical and chemical recovery technologies of PET was reviewed， and the characteristics of different recovery technologies were analyzed comparatively. This paper provides a reference for the future research of PET recycling.
TANG Qingfeng, LI Qinmei, WANG Jiamin, ZHANG Yuxiang, GAO Xia
Abstract (
2205 )
PDF (4408 KB)(
1914
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HTML (
68 )
Micro Fourier?transform infrared spectroscopy （micro?FTIR） was used to analyze and identify microplastics with different particle sizes and different compositions. These microplastics include the plastic， fiber or rubber fragments with particle size less than 5 mm. The advantages and disadvantages of three measurement modes including reflection， transmission and attenuated total reflection and their scanning technologies in the identification and analysis of microplastics were systematically described. Based on the attenuated total reflection technique of micro?FTIR， the microplastic obtained from the Beijing landscape water were analyzed and identified. The results indicated that this method was simple， accurate and reliable.
CHEN Xinqi, BAI Yun, LIU Shanshan, GAO Xia, LIU Weili, ZHANG Mei, WU Yuwei, HUANG Yan, ZHAO Hongliang
Abstract (
1780 )
PDF (1554 KB)(
1325
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HTML (
47 )
The contents of polylactic acid （PLA）， poly（butylene succinate） （PBS） and poly（butylene adipate terephthalate） （PBAT） were detected by hydrogen nuclear magnetic resonance spectroscopy （1H?NMR） with 1，2，4，5?tetrachlorobenzene as the internal standard. The method identified the characteristic peaks of PLA， PBS and PBAT for quantitative analysis and established their quantitative calculation formulas. The results indicated that good linear relationships （R>0.99） were achieved among the characteristic peak area ratios of 1∶5~5∶1 for the internal standard substance and target substance. The relative standard deviations of the precision and repeatability of the three components were all lower than 3 %. The results indicated that this method was accurate， simple and feasible to detect the contents of PLA， PBS and PBAT. In addition， the contents of PLA， PBS and PBAT in 7 batches of commercial biodegradable shopping bags were determined， and the results demonstrated that the method was suitable for rapid determination of the contents of PLA， PBS， and PBAT in the biodegradable samples.
Machinery and Mould
HE Hezhi, WANG Yi, GAO Jun
Abstract (
733 )
PDF (3050 KB)(
444
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HTML (
15 )
The blends of recycled polyethylene （rPE） and polyamide 6 （PA6） were prepared separately using a traditional twin?screw extruder and a novel eccentric rotor extruder. Their mechanical properties， thermal properties， dynamic thermomechanical behavior and microstructure were investigated. The results indicated that the young's modulus of the blends prepared with these two types of equipment increased significantly in the presence of PA6， but their elongation at break decreased sharply. The tensile strength of the blends prepared with the twin?screw extruder decreased slowly with an increase in the weight fraction of PA6， whereas the blends prepared with the eccentric rotor showed a decrease at first and then an increase in tensile strength. The two types of processing equipments had little effect on the crystallization and melting behaviors of the blends. The morphological analysis demonstrated that the blends prepared with the eccentric rotor extruder had better compatibility than that with the twin?screw extruder as confirmed by the difference between their glass transition temperatures. In conclusion， the eccentric rotor can generate a compulsory compatibilizing effect on the incompatible blending systems.
HUANG Xingyuan, PAN Liuwen, TAN Lei, WANG Han
Abstract (
928 )
PDF (2321 KB)(
556
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HTML (
24 )
This paper proposed a hot air melting method for the reuse of waste plastics. With this method， the waste plastics was melted directly in the hot air and then extruded and palletized. There is no crashing needed in the whole process， generating no noise and dust accordingly. The temperature of hot air can be controlled easily， and therefore the degradation caused by overheating can be avoided. The waste heat can be reused through hot air recycling. Based the theoretical analysis， an experimental prototype was designed and manufactured， following by conducting a validation experiment.
