Materials and Properties
GONG Zheng, LI Weijie, ZHAO Ling, HU Dongdong
Abstract (
326 )
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326
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21 )
Isotactic polybutene⁃1 （iPB⁃1） with a long⁃chain branching and cross⁃linking structure was prepared by using dicumyl peroxide as an initiator and zinc dimethyldithiocarbamate （ZDMC） and pentaerythritol triacrylate as dual monomers. Then， iPB⁃1 foams were prepared through supercritical CO2 foaming. The effects of chain⁃extended modification on the melting， crystallization， rheological， and foaming behaviors of iPB⁃1 were investigated. The results indicated that the long⁃chain branching structure resulted in an increase in the crystallization temperature of iPB⁃1 but a decrease in its crystallinity. The modified iPB⁃1 obtained an improvement in the melt viscoelasticity and relaxation time， resulting in more remarkable shear thinning along with a significant strain⁃hardening phenomenon. The modified iPB⁃1 with a long⁃chain branching structure exhibited a wider foaming temperature window and a more uniform cellular structure.
2023, 37 (12):
1-6;
Abstract (
0 )
PDF (0 KB)(
0
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Isotactic polybutene-1 （iPB-1） with a long-chain branching and cross-linking structure was prepared by using dicumyl peroxide as an initiator and zinc dimethyldithiocarbamate （ZDMC） and pentaerythritol triacrylate as dual monomers. Then， iPB-1 foams were prepared through supercritical CO2 foaming. The effects of chain-extended modification on the melting， crystallization， rheological， and foaming behaviors of iPB-1 were investigated. The results indicated that the long-chain branching structure resulted in an increase in the crystallization temperature of iPB-1 but a decrease in its crystallinity. The modified iPB-1 obtained an improvement in the melt viscoelasticity and relaxation time， resulting in more remarkable shear thinning along with a significant strain-hardening phenomenon. The modified iPB-1 with a long-chain branching structure exhibited a wider foaming temperature window and a more uniform cellular structure.
Materials and Properties
WANG Yao, XIAO Yuan, CHENG Chuanrui, ZHAO Peng, ZHANG Chen, XIONG Daoying, JIANG Chuanxia, ZHANG He
Abstract (
221 )
PDF (5380 KB)(
266
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11 )
Based on the microencapsulated epoxy⁃amine chemistry self⁃healing system， the relevant properties involved in the practical application of self⁃healing anticorrosion epoxy coatings were investigated， which included the service environment， thermal stability， and long⁃term anticorrosion performance after the damage event of the self⁃healing anticorrosion coatings， as well as the long⁃term stability of the self⁃healing function for the self⁃healing anticorrosion epoxy coatings. The results indicated that the self⁃healing system exhibited excellent anticorrosion performance when healed in the water environment. The medium⁃high temperature heat treatment did not reduce the anticorrosion performance of the self⁃healing coatings at 80 ℃ for 24 h and or at 5 min for 200 ℃. The 180⁃day long⁃term anticorrosion performance of the self⁃healing coatings after damage healing is excellent. Meanwhile， the self⁃healing anticorrosion coatings have a good long⁃term stability.
2023, 37 (12):
7-13;
Abstract (
0 )
PDF (0 KB)(
0
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Based on the microencapsulated epoxy-amine chemistry self-healing system， the relevant properties involved in the practical application of self-healing anticorrosion epoxy coatings were investigated， which included the service environment， thermal stability， and long-term anticorrosion performance after the damage event of the self-healing anticorrosion coatings， as well as the long-term stability of the self-healing function for the self-healing anticorrosion epoxy coatings. The results indicated that the self-healing system exhibited excellent anticorrosion performance when healed in the water environment. The medium-high temperature heat treatment did not reduce the anticorrosion performance of the self-healing coatings at 80 ℃ for 24 h and or at 5 min for 200 ℃. The 180-day long-term anticorrosion performance of the self-healing coatings after damage healing is excellent. Meanwhile， the self-healing anticorrosion coatings have a good long-term stability.
Materials and Properties
SUN Zijia, LUO Cuimei, WANG Qihang, WANG Xujie, MU Jun
Abstract (
235 )
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240
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HTML (
12 )
Lignocellulosic nanocrystals （L⁃CNC） were prepared by using bamboo residue as a raw material and then modified by grafting octadecylamine （ODA） onto their surfaces through utilizing the chemical reactivity of catechol groups in tannic acid （TA）. A series of composite films based on modified L⁃CNC and poly（lactic acid） （PLA） were prepared through solution casting. The effect of L⁃CNC content on the mechanical， antioxidant， UV shielding， and hydrophobic properties of the composite films were investigated. The results indicated that the grafting modification of ODA improved the compatibility of L⁃CNC with PLA. When the content of ODA⁃TA@L⁃CNC was 1 wt %， The composite films showed elongation at break of 20.42 % and fracture toughness of 8.55 MJ/m3， which were 3 times and 10 times higher than those of neat PLA film， respectively. Meanwhile， their tensile strength was increased to 46.84 MPa， and their hydrophobic performance was significantly improved with a stable contact angle of about 100° within 1 minute. When the content of ODA⁃TA@L⁃CNC was 1.5 wt %， the composite films obtained a free radical scavenging rate of 49.30 % for DPPH， indicating a good antioxidant property. They also gained an average blocking ratio of 44.81 % in the wavelength range of the ultraviolet region. This means that the composite films can shield most of the UVB spectrum （280~320 nm）.
2023, 37 (12):
14-22;
Abstract (
0 )
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0
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Lignocellulosic nanocrystals （L-CNC） were prepared by using bamboo residue as a raw material and then modified by grafting octadecylamine （ODA） onto their surfaces through utilizing the chemical reactivity of catechol groups in tannic acid （TA）. A series of composite films based on modified L-CNC and poly（lactic acid） （PLA） were prepared through solution casting. The effect of L-CNC content on the mechanical， antioxidant， UV shielding， and hydrophobic properties of the composite films were investigated. The results indicated that the grafting modification of ODA improved the compatibility of L-CNC with PLA. When the content of ODA-TA@L-CNC was 1 wt %， The composite films showed elongation at break of 20.42 % and fracture toughness of 8.55 MJ/m3， which were 3 times and 10 times higher than those of neat PLA film， respectively. Meanwhile， their tensile strength was increased to 46.84 MPa， and their hydrophobic performance was significantly improved with a stable contact angle of about 100° within 1 minute. When the content of ODA-TA@L-CNC was 1.5 wt %， the composite films obtained a free radical scavenging rate of 49.30 % for DPPH， indicating a good antioxidant property. They also gained an average blocking ratio of 44.81 % in the wavelength range of the ultraviolet region. This means that the composite films can shield most of the UVB spectrum （280~320 nm）.
Materials and Properties
WANG Rongrong, JIANG Tao, SUN Shaoyang, ZHOU Zhou, WANG Xiang, SHEN Ying, XING Jian
Abstract (
231 )
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257
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HTML (
7 )
Polyimide （PI）/multi⁃wall carbon nanotubes （MWCNTs） hybrid nanofibers were prepared through a one⁃step electrospinning technology using P84 staple fiber as a matrix. The resultant nanofibers exhibited a minimum nanoscale fiber diameter of （196.61±108.56） nm and a hierarchical porous structure. FTIR spectroscopic analysis indicated that the as⁃prepared nanofibers presented all the characteristic absorption bonds of the original P84 staple fiber. However， the as⁃prepared nanofibers show lower crystallinity and a lower decomposition temperature （590 ℃） than those of the original P84 staple fibers （620 ℃）. With the addition of MWCNTs， there is no influence on the chemical structure and thermal stability of the PI nanofibers. Nevertheless， the diameter of the hybrid nanofibers tended to decrease， and their crystallinity and mechanical strength increased compared to pure PI nanofibers. Notably， compared to pure PI nanofibers， the tensile stress of the hybrid nanofibers increases by 65 % with the addition of 0.5 wt% MWCNTs.
2023, 37 (12):
23-28;
Abstract (
0 )
PDF (0 KB)(
0
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Polyimide （PI）/multi-wall carbon nanotubes （MWCNTs） hybrid nanofibers were prepared through a one-step electrospinning technology using P84 staple fiber as a matrix. The resultant nanofibers exhibited a minimum nanoscale fiber diameter of （196.61±108.56） nm and a hierarchical porous structure. FTIR spectroscopic analysis indicated that the as-prepared nanofibers presented all the characteristic absorption bonds of the original P84 staple fiber. However， the as-prepared nanofibers show lower crystallinity and a lower decomposition temperature （590 ℃） than those of the original P84 staple fibers （620 ℃）. With the addition of MWCNTs， there is no influence on the chemical structure and thermal stability of the PI nanofibers. Nevertheless， the diameter of the hybrid nanofibers tended to decrease， and their crystallinity and mechanical strength increased compared to pure PI nanofibers. Notably， compared to pure PI nanofibers， the tensile stress of the hybrid nanofibers increases by 65 % with the addition of 0.5 wt% MWCNTs.
Materials and Properties
DAI Xiying, ZHANG Chong, WAN Caixia, YANG Wei, XING Zhaoliang
Abstract (
285 )
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218
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6 )
This article focused on the relationship between the processing parameters of biaxially oriented polypropylene （BOPP） capacitor films and breakdown field strength， as well as the microstructure affecting breakdown field strength. The results indicated that the microstructure affecting breakdown field strength included the crystallinity， mobility of molecular chains in the amorphous region， and roughness of BOPP capacitor films. The higher crystallinity， the more serious was the mobility of molecular chains in the amorphous region limited， the smaller was the roughness， and the higher was the breakdown field strength. During the processing， the molecular chain motion ability in the amorphous region and roughness could be reduced through appropriately reducing the longitudinal stretching temperature. In addition， the crystallinity of BOPP capacitor films increased with an increase in the transverse stretching temperature， thus reaching the goal of improving the breakdown field strength. The establishment of the relationship between the processing， structure and performance of BOPP capacitive films provides a fundamental basis for improving their breakdown field strength in production lines.
2023, 37 (12):
29-34;
Abstract (
0 )
PDF (0 KB)(
0
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This article focused on the relationship between the processing parameters of biaxially oriented polypropylene （BOPP） capacitor films and breakdown field strength， as well as the microstructure affecting breakdown field strength. The results indicated that the microstructure affecting breakdown field strength included the crystallinity， mobility of molecular chains in the amorphous region， and roughness of BOPP capacitor films. The higher crystallinity， the more serious was the mobility of molecular chains in the amorphous region limited， the smaller was the roughness， and the higher was the breakdown field strength. During the processing， the molecular chain motion ability in the amorphous region and roughness could be reduced through appropriately reducing the longitudinal stretching temperature. In addition， the crystallinity of BOPP capacitor films increased with an increase in the transverse stretching temperature， thus reaching the goal of improving the breakdown field strength. The establishment of the relationship between the processing， structure and performance of BOPP capacitive films provides a fundamental basis for improving their breakdown field strength in production lines.
Materials and Properties
LEI Ming, XIA Gengpei, JIANG Yu, AI Daoyi, YOU Zongying, YU Siya, TU Jianlei, CHENG Haonan, XIANG Wei, HUANG Daiqi
Abstract (
256 )
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321
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HTML (
5 )
Polyether ether ketone （PEEK）/fluorinated graphite composites were prepared through melt blending. Their tribological properties against 304# steel and 45# steel were investigated by using a ring⁃on⁃block friction and wear test machine， their worn scar surfaces were analyzed by SEM， and their tribological mechanism were explored. The results indicated that the friction coefficient between the composites and 304# steel decreased gradually with an increase in the content of fluorinated graphite， whereas the change in friction coefficient with 45# steel was not significant. When the content of fluorinated graphite is lower than 10 wt%， the composites exhibit a lower friction coefficient against 45# steel. When the content of fluorinated graphite is higher than 15 wt%， the composites show a lower friction coefficient against 304# steel. According to different loads， the composites with exhibit poor tribological performance toward two types of friction rings under a load of 300 N. However， composites present a higher friction coefficient but a lower wear rate under a load of 100 N.
2023, 37 (12):
35-40;
Abstract (
0 )
PDF (0 KB)(
0
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Polyether ether ketone （PEEK）/fluorinated graphite composites were prepared through melt blending. Their tribological properties against 304# steel and 45# steel were investigated by using a ring-on-block friction and wear test machine， their worn scar surfaces were analyzed by SEM， and their tribological mechanism were explored. The results indicated that the friction coefficient between the composites and 304# steel decreased gradually with an increase in the content of fluorinated graphite， whereas the change in friction coefficient with 45# steel was not significant. When the content of fluorinated graphite is lower than 10 wt%， the composites exhibit a lower friction coefficient against 45# steel. When the content of fluorinated graphite is higher than 15 wt%， the composites show a lower friction coefficient against 304# steel. According to different loads， the composites with exhibit poor tribological performance toward two types of friction rings under a load of 300 N. However， composites present a higher friction coefficient but a lower wear rate under a load of 100 N.
Materials and Properties
SUN Yibo, LIU Yaning, LU Haofan, CHEN Shihong, WANG Xiangdong, WU Lili
Abstract (
306 )
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362
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HTML (
10 )
A multifunctional epoxy chain extender CE and an antioxidant B215 were used to modify linear polyamide 66 （PA66） through melting chain extension， and a series of microporous CEPA66 foams were prepared by supercritical CO2. The branched PA66 was formed by the introduction of the chain extender CE， and its crystallization behavior， energy⁃storage modulus， and complex viscosity were characterized by using DSC， FTIR and rotary rheometer. The use of CE effectively improved the melt strength of PA66， and its addition amount was optimized to obtain PA66 with a high branching and low crosslinking degrees. The PA66 microcellular foams were successfully obtained at a saturation temperature of 275 ℃. Their cell size and cell density are 23 μm and 3.5×109 cells /cm3， respectively.
2023, 37 (12):
41-46;
Abstract (
0 )
PDF (0 KB)(
0
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A multifunctional epoxy chain extender CE and an antioxidant B215 were used to modify linear polyamide 66 （PA66） through melting chain extension， and a series of microporous CEPA66 foams were prepared by supercritical CO2. The branched PA66 was formed by the introduction of the chain extender CE， and its crystallization behavior， energy-storage modulus， and complex viscosity were characterized by using DSC， FTIR and rotary rheometer. The use of CE effectively improved the melt strength of PA66， and its addition amount was optimized to obtain PA66 with a high branching and low crosslinking degrees. The PA66 microcellular foams were successfully obtained at a saturation temperature of 275 ℃. Their cell size and cell density are 23 μm and 3.5×109 cells /cm3， respectively.
Processing and Application
WANG Minghuan, LIU Yuanyuan, XU Ran, HE Yadong, XIN Chunling, REN Feng
Abstract (
326 )
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180
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HTML (
10 )
Aiming at the problems existing in the spreading device， the fiber bundle spreading mechanism was investigated. Based on the laboratory mechanical spreading equipment， a vibration⁃blowing spreading device was constructed through a combination of vibration spreading and air⁃blowing spreading， and a theoretical model was established for carbon fiber spreading. The spreading process parameters were optimized. The investigation results indicated that with an increase in the airflow speed， the vibration amplitude and vibration frequency could help to improve the spreading width and uniformity of carbon fiber. This ensures a lower spreading fracture rate up to 0.036 % compared to the traditional mechanical spreading process.
2023, 37 (12):
47-53;
Abstract (
0 )
PDF (0 KB)(
0
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Aiming at the problems existing in the spreading device， the fiber bundle spreading mechanism was investigated. Based on the laboratory mechanical spreading equipment， a vibration-blowing spreading device was constructed through a combination of vibration spreading and air-blowing spreading， and a theoretical model was established for carbon fiber spreading. The spreading process parameters were optimized. The investigation results indicated that with an increase in the airflow speed， the vibration amplitude and vibration frequency could help to improve the spreading width and uniformity of carbon fiber. This ensures a lower spreading fracture rate up to 0.036 % compared to the traditional mechanical spreading process.
Processing and Application
WEI Chiyuan, XIE Jingjing, SHI Peixin, GAO Qianhong, LI Haixia
Abstract (
286 )
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526
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HTML (
17 )
A compression thermal aging method was employed to accelerate the aging of foamed silicone rubber for sealing at 180 ºC over different time. The tearing performance， mass loss rate， microstructure and infrared spectroscopy of the aged rubber samples were analyzed， and their lifetime was evaluated by using compression rebound rate as an important parameter. The results indicated that the foamed silicone rubber exhibited a slight increase in the tear strength with an increase in aging time （within 36 h）， followed by a decrease after aging for over 72 h. With a continuous increase in the aging time， there is a gradual increase in the mass loss rate of the foamed silicone rubber from 0 to 5.5 wt% within 144 h. The infrared spectroscopic analysis indicated that the main and side chains on the surface molecular chain of the foamed silicone rubber were broken after thermal aging at 180 ℃. However， its main chains in the internal part were mainly cross⁃linked， but its side chains were mainly broken. The morphological observation indicated that there were cracks and pores appearing on the surface of the foamed silicone rubber with an increase in aging time， whereas the internal pores decreased gradually from a large size to the small one. The service lifetime of the foamed silicone rubber material was evaluated by using experimental data on the compression aging rebound rate. The results showed that the service lifetimes were 15.65， 7.01， and 5.11 years at 23， 35， and 40 ℃， respectively.
2023, 37 (12):
54-59;
Abstract (
0 )
PDF (0 KB)(
0
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A compression thermal aging method was employed to accelerate the aging of foamed silicone rubber for sealing at 180 oC over different time. The tearing performance， mass loss rate， microstructure and infrared spectroscopy of the aged rubber samples were analyzed， and their lifetime was evaluated by using compression rebound rate as an important parameter. The results indicated that the foamed silicone rubber exhibited a slight increase in the tear strength with an increase in aging time （within 36 h）， followed by a decrease after aging for over 72 h. With a continuous increase in the aging time， there is a gradual increase in the mass loss rate of the foamed silicone rubber from 0 to 5.5 wt% within 144 h. The infrared spectroscopic analysis indicated that the main and side chains on the surface molecular chain of the foamed silicone rubber were broken after thermal aging at 180 ℃. However， its main chains in the internal part were mainly cross-linked， but its side chains were mainly broken. The morphological observation indicated that there were cracks and pores appearing on the surface of the foamed silicone rubber with an increase in aging time， whereas the internal pores decreased gradually from a large size to the small one. The service lifetime of the foamed silicone rubber material was evaluated by using experimental data on the compression aging rebound rate. The results showed that the service lifetimes were 15.65， 7.01， and 5.11 years at 23， 35， and 40 ℃， respectively.
Processing and Application
LI Haoyi, WANG Yiming, DING Xi, ZHANG Yi, BAI Jingyu, LI Feifei, ZHANG Yueyong, YANG Weimin
Abstract (
418 )
PDF (1519 KB)(
705
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HTML (
6 )
The use of electrospun micro/nanofibers for drug delivery can obtain a controllable drug release， which has gradually become a research hotspot in recent years. To further promote the application of electrospinning in the field of drug release， this paper introduced the characteristics， advantages， and disadvantages of solution， emulsion and melt electrospinning for the preparation of drug loaded fibers in view of the preparation technology of electrospun drug⁃loaded fibers. Subsequently， the influencing factors and drug loading forms of electrospun drug⁃loaded fibers in drug release were summarized. Finally， the latest research progress in the electrospun drug⁃loaded fibers in the fields of transdermal drug delivery， mucosal drug delivery and tissue engineering was reviewed， and the application potential of electrospinning in drug delivery was analyzed.
2023, 37 (12):
60-69;
Abstract (
0 )
PDF (0 KB)(
0
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The use of electrospun micro/nanofibers for drug delivery can obtain a controllable drug release， which has gradually become a research hotspot in recent years. To further promote the application of electrospinning in the field of drug release， this paper introduced the characteristics， advantages， and disadvantages of solution， emulsion and melt electrospinning for the preparation of drug loaded fibers in view of the preparation technology of electrospun drug-loaded fibers. Subsequently， the influencing factors and drug loading forms of electrospun drug-loaded fibers in drug release were summarized. Finally， the latest research progress in the electrospun drug-loaded fibers in the fields of transdermal drug delivery， mucosal drug delivery and tissue engineering was reviewed， and the application potential of electrospinning in drug delivery was analyzed.
Processing and Application
ZHANG Xuemin, WANG Qinggang, ZHANG Xueru, LI Houbu, QI Guoquan, DING Han, GAO Xiong, YANG Wenhui
Abstract (
252 )
PDF (2651 KB)(
317
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HTML (
8 )
A barrier layer was added according to the structure of the composite pipe， and a three⁃dimensional model was established for high barrier non⁃metallic flexible composite pipes based on the finite element simulation. The influence of geometry and process parameters of the barrier layer on the pressure⁃bearing performance of the composite pipes was analyzed， and the optimal parameters of the barrier layer were determined. The results indicated that the stress of the aramid reinforced layer reached a maximum， followed by the aluminum foil barrier layer when the high barrier non⁃metallic flexible composite pipes were under pressure. The stresses of the inner lining layer and outer protective layer were the lowest. The thickness of the aluminum foil barrier layer generated the greatest influence on the pressure bearing performance of the composite pipes， followed by the influence of friction coefficient. The influence of width and winding angle of the aluminum foil layer was the lowest. Considering the pipeline stress and design cost， the optimum thickness， width， and winding angle of the aluminum foil barrier layer were determined to be 0.15 mm， 200 mm， and 70°， respectively.
2023, 37 (12):
70-77;
Abstract (
0 )
PDF (0 KB)(
0
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A barrier layer was added according to the structure of the composite pipe， and a three-dimensional model was established for high barrier non-metallic flexible composite pipes based on the finite element simulation. The influence of geometry and process parameters of the barrier layer on the pressure-bearing performance of the composite pipes was analyzed， and the optimal parameters of the barrier layer were determined. The results indicated that the stress of the aramid reinforced layer reached a maximum， followed by the aluminum foil barrier layer when the high barrier non-metallic flexible composite pipes were under pressure. The stresses of the inner lining layer and outer protective layer were the lowest. The thickness of the aluminum foil barrier layer generated the greatest influence on the pressure bearing performance of the composite pipes， followed by the influence of friction coefficient. The influence of width and winding angle of the aluminum foil layer was the lowest. Considering the pipeline stress and design cost， the optimum thickness， width， and winding angle of the aluminum foil barrier layer were determined to be 0.15 mm， 200 mm， and 70°， respectively.
Standard and Test
XU Lidan, LI Yu, XU Haiyun, XIANG Lubing, CHENG Debao, WANG Zhiwei
Abstract (
270 )
PDF (1267 KB)(
320
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HTML (
7 )
Polyethylene （PE） pipes were prepared through melt extrusion molding using PE compound， PE with color masterbatch， and PE with external recycled material as raw materials. Carbon black （CB） dispersion， CB content， ash content， oxidation induction time， elongation at break， and trace metal element content of the pipes were measured according to national standard GB 15558.2—2023， and their performance differences were studied. The results indicated that the CB dispersion， CB content， and ash qualification rate of the pipe products made of polyethylene compound were 100 %. The trace iron and calcium contents were not more than 10 and 250 mg/kg， respectively. This indicates that the compound become a preferred raw material for PE pipes. The CB content of the PE pipes produced by adding color masterbatch is not stable， even at a concentration of over 2.6% or below 0.7 %. The dispersion level of CB with color masterbatch reached A3~D， indicating instability. The dispersion level of CB was significantly lower than that of compound. The ash qualification rate of products was 35 % when using white materials with external recycled materials or compound with external recycled materials. The content of trace elements such as iron and calcium increased significantly in products with the addition of external recycled materials. In the compound with 20 % external recycled materials， the iron and calcium contents were as high as 18.4 and 862 mg/kg， respectively， with an uneven distribution of trace metal elements.
2023, 37 (12):
78-83;
Abstract (
0 )
PDF (0 KB)(
0
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Polyethylene （PE） pipes were prepared through melt extrusion molding using PE compound， PE with color masterbatch， and PE with external recycled material as raw materials. Carbon black （CB） dispersion， CB content， ash content， oxidation induction time， elongation at break， and trace metal element content of the pipes were measured according to national standard GB 15558.2—2023， and their performance differences were studied. The results indicated that the CB dispersion， CB content， and ash qualification rate of the pipe products made of polyethylene compound were 100 %. The trace iron and calcium contents were not more than 10 and 250 mg/kg， respectively. This indicates that the compound become a preferred raw material for PE pipes. The CB content of the PE pipes produced by adding color masterbatch is not stable， even at a concentration of over 2.6% or below 0.7 %. The dispersion level of CB with color masterbatch reached A3~D， indicating instability. The dispersion level of CB was significantly lower than that of compound. The ash qualification rate of products was 35 % when using white materials with external recycled materials or compound with external recycled materials. The content of trace elements such as iron and calcium increased significantly in products with the addition of external recycled materials. In the compound with 20 % external recycled materials， the iron and calcium contents were as high as 18.4 and 862 mg/kg， respectively， with an uneven distribution of trace metal elements.
Plastic and Environment
HUO Zhanbin, FU Ye, WENG Yunxuan
Abstract (
444 )
PDF (2850 KB)(
1015
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HTML (
16 )
This present work focuses on the biodegradation behavior of poly（butylene adipate⁃co⁃terephthalate） （PBAT） biodegradable mulch film in farmland soil and simulated soil environments. The effects of polyester relative molecular weight and organic fillers on the degradation rate of mulch film in two soil environments were investigated. During the degradation process， the breakage of ester bond in PBAT molecular chain occurred， and meanwhile the crystallinity of PBAT increased. The O/C content ratio of the samples LN⁃1， LN⁃3 and LN⁃5 increased by 54 %， 105 % and 184 %， respectively. The lower molecular weight polyester degraded faster in the same environment. Organic filler starch can accelerate the physical disintegration and biodegradation process of the mulch film. The linear， exponential， and power function equations for the degradation degree⁃time relationship was established by using carbonyl index changes， in which the power function equation performed the highest coefficient of determination and strongest correlation. Accordingly， a power function equation relationship between the degradation time of the mulch film in farmland and simulated soil environments was obtained. The degradation behavior of the mulch film converted into soil after summer harvest in North China Plain was simulated in the laboratory.
2023, 37 (12):
84-90;
Abstract (
0 )
PDF (0 KB)(
0
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This present work focuses on the biodegradation behavior of poly（butylene adipate-co-terephthalate） （PBAT） biodegradable mulch film in farmland soil and simulated soil environments. The effects of polyester relative molecular weight and organic fillers on the degradation rate of mulch film in two soil environments were investigated. During the degradation process， the breakage of ester bond in PBAT molecular chain occurred， and meanwhile the crystallinity of PBAT increased. The O/C content ratio of the samples LN-1， LN-3 and LN-5 increased by 54 %， 105 % and 184 %， respectively. The lower molecular weight polyester degraded faster in the same environment. Organic filler starch can accelerate the physical disintegration and biodegradation process of the mulch film. The linear， exponential， and power function equations for the degradation degree-time relationship was established by using carbonyl index changes， in which the power function equation performed the highest coefficient of determination and strongest correlation. Accordingly， a power function equation relationship between the degradation time of the mulch film in farmland and simulated soil environments was obtained. The degradation behavior of the mulch film converted into soil after summer harvest in North China Plain was simulated in the laboratory.
Plastic and Environment
LIU Baoying, YANG Chenguang, LI Guang, ZHU Yixiang, HE Yongsen, LI Qingzheng, ZHAI Hua
Abstract (
292 )
PDF (2524 KB)(
468
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HTML (
7 )
This paper summarizes the working principle and main application progress in the infrared spectrum analysis technology for waste automotive plastics separation. This review can provide some references for the research and development of waste automotive plastics separation technologies and the promotion of the relevant equipment in the future.
2023, 37 (12):
91-100;
Abstract (
0 )
PDF (0 KB)(
0
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This paper summarizes the working principle and main application progress in the infrared spectrum analysis technology for waste automotive plastics separation. This review can provide some references for the research and development of waste automotive plastics separation technologies and the promotion of the relevant equipment in the future.
Machinery and Mould
WANG Congxiao, ZHENG Jiaxin, ZHAO Yuyin, SU Zhenqian, REN Feng
Abstract (
264 )
PDF (3415 KB)(
304
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HTML (
7 )
T he effect of screw configurations of mixing section on the performance of PBAT/Talc composites was investigated through a combination of simulation and experimentation. The results indicated that the uniform dispersion of fillers in the matrix was positively correlated with the number of mixing screw elements for dispersion distribution. However， an increase in the number of dispersion distribution elements accentuated the degradation of the PBAT matrix， leading to a decrease in the mechanical properties. This study demonstrated that the composites exhibited optimal performance when prepared through a combination of sequential distribution and dispersion of screw elements.
2023, 37 (12):
101-108;
Abstract (
0 )
PDF (0 KB)(
0
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T he effect of screw configurations of mixing section on the performance of PBAT/Talc composites was investigated through a combination of simulation and experimentation. The results indicated that the uniform dispersion of fillers in the matrix was positively correlated with the number of mixing screw elements for dispersion distribution. However， an increase in the number of dispersion distribution elements accentuated the degradation of the PBAT matrix， leading to a decrease in the mechanical properties. This study demonstrated that the composites exhibited optimal performance when prepared through a combination of sequential distribution and dispersion of screw elements.
Machinery and Mould
CAI Houdao, LI Guijin, CHEN Yun
Abstract (
240 )
PDF (2105 KB)(
293
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HTML (
13 )
Moldflow software was used to simulate the injection process. The influences of the traditional cooling channel design and conformal cooling channel design of the mold cooling system on the cooling of product formation was compared and analyzed. The maximum temperature difference of the conformal cooling channel design between the product center and both sides was controlled within 4 ℃， which reduced the jacking cooling time by 17% and the total deformation by 38.61% compared to that of the traditional cooling channel design. This resulted in the optimal cooling uniformity of the mold with a conformal cooling channel. A hot runner injection mold of the conformal cooling channel was designed by using a inside and outside slider mechanism， an angle pin core⁃pulling mechanism， a lifter mechanism， and an “ejector pins pushing+ejector block pushing” mechanism. This design made the product released smoothly. The mold design was advanced， and the latch⁃style mechanism realized the order opening of two⁃plate injection mold， which could ensure the reliability of mold operation.
2023, 37 (12):
109-114;
Abstract (
0 )
PDF (0 KB)(
0
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Moldflow software was used to simulate the injection process. The influences of the traditional cooling channel design and conformal cooling channel design of the mold cooling system on the cooling of product formation was compared and analyzed. The maximum temperature difference of the conformal cooling channel design between the product center and both sides was controlled within 4 ℃， which reduced the jacking cooling time by 17% and the total deformation by 38.61% compared to that of the traditional cooling channel design. This resulted in the optimal cooling uniformity of the mold with a conformal cooling channel. A hot runner injection mold of the conformal cooling channel was designed by using a inside and outside slider mechanism， an angle pin core-pulling mechanism， a lifter mechanism， and an “ejector pins pushing+ejector block pushing” mechanism. This design made the product released smoothly. The mold design was advanced， and the latch-style mechanism realized the order opening of two-plate injection mold， which could ensure the reliability of mold operation.
Review
ZHANG Jianzhong, FANG Yang, ZHANG Wangbin, HUANG Teng, YU Youming, DAI Jinfeng, SONG Pingan
Abstract (
293 )
PDF (588 KB)(
291
)
HTML (
4 )
This paper overview the research and application progress in the flame⁃retardant modification of thermosetting unsaturated polyester resins （UPRs） in recent years， which includes the additive and reactive flame⁃retardant methods. The advantages and disadvantages of different modes and types of flame retardancy for UPRs were compared. Moreover， the future development of flame⁃retardant UPRs was also prospected.
2023, 37 (12):
115-123;
Abstract (
0 )
PDF (0 KB)(
0
)
This paper overview the research and application progress in the flame-retardant modification of thermosetting unsaturated polyester resins （UPRs） in recent years， which includes the additive and reactive flame-retardant methods. The advantages and disadvantages of different modes and types of flame retardancy for UPRs were compared. Moreover， the future development of flame-retardant UPRs was also prospected.
Review
WANG Zicheng, YANG Biao
Abstract (
402 )
PDF (774 KB)(
570
)
HTML (
18 )
This paper reviews the advances in biodegradable barrier materials based on the strategies to improve the barrier properties， such as copolymerization， blending， filling composition， multilayer lamination， and construction of surface barrier coating. Moreover， the future focus and feasibility were analyzed to provide a valuable reference for developing biodegradable barrier materials.
2023, 37 (12):
124-134;
Abstract (
0 )
PDF (0 KB)(
0
)
This paper reviews the advances in biodegradable barrier materials based on the strategies to improve the barrier properties， such as copolymerization， blending， filling composition， multilayer lamination， and construction of surface barrier coating. Moreover， the future focus and feasibility were analyzed to provide a valuable reference for developing biodegradable barrier materials.
Review
GUO Wenjiao, LI Juan, LI Ying
Abstract (
216 )
PDF (917 KB)(
368
)
HTML (
7 )
This review introduced the progress of polypropylene（PP）⁃based nanocomposites in cross⁃linked polyethylene （XLPE） cable insulation materials， particularly focusing on the various parameters of nanofillers and their impact on the electrical properties of PP⁃based HVDC cable insulation materials. Finally， a promising outlook was presented for the application of PP⁃based nanocomposites in HVDC cable insulation materials.
2023, 37 (12):
135-142;
Abstract (
0 )
PDF (0 KB)(
0
)
This review introduced the progress of polypropylene（PP）-based nanocomposites in cross-linked polyethylene （XLPE） cable insulation materials， particularly focusing on the various parameters of nanofillers and their impact on the electrical properties of PP-based HVDC cable insulation materials. Finally， a promising outlook was presented for the application of PP-based nanocomposites in HVDC cable insulation materials.
