Materials and Properties
LI Borui, XIAO Shujuan , WU Shuanghan , YU Shouwu
Abstract (
1082 )
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851
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709 )
The co-microencapsulated ammonium polyphosphate/aluminum hypophosphite ［M（A-A）］ was prepared as a flame retardant using melamine–formaldehyde （MF） resin as wall material. The encapsulating effect of MF was examined by Fourier-transform infrared spectroscopy， scanning electron microscopy and water solubility test. The flame?retardant effect of M（A-A） on polypropylene （PP） was investigated by vertical combustion test， limit oxygen index and cone calorimeter. The mechanical properties of flame?retardant PP were characterized by impact and tensile tests. The results indicated that ammonium polyphosphate/aluminum hypophosphite was successfully encapsulated by MF resin， leading to an effective improvement of water resistance. M（A-A） exhibited better flame retarding efficiency than the pristine flame retardant at the same loading in PP. The heat release rate and total heat release of flame?retardant PP were reduced significantly， and its impact strength increased at first and then tended to decrease with the increase of M（A-A） content. The microencapsulation of flame retardants seemed to reduce the deterioration in tensile properties of PP.
YANG Fan, ZHU Jun, GUAN Li, ZHANG Baolin
Abstract (
819 )
PDF (4318 KB)(
988
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36 )
HPR1018HA polyethylene （PE） is a type of representative high-strength metallocene PE resin special for film blowing， and it has found widely applications under a huge market capacity. HPR1018HA PE is mainly processed by blow molding. In this paper， the effect of different processing parameters on the physical properties was investigated for the films processed by use of HPR1018HA PE. The results indicated that the dart impact performance of HPR1018HA PE was significantly improved with an increase of processing temperature， and the dart impact performance of HPR1018HA PE was significantly improved with an increase of inflation ratio. Meanwhile， the variation trend of physical properties was investigated for the films processed using the blended resins of HPR1018HA PE with PE-LD and PE-LLD. The results indicated that when HPR1018HA PE was blended with less than 50 wt% of PE-LD with a melt index of 0.3 g/10 min， the tensile strength of the films decreased by about 18 %， and the variation rate of their right-angle tear strength was less than 5%. When HPR1018HA PE was blended with PE-LD with a melt flow index of 2.0 g/10 min， the tensile strength of the films decreased by about 40 %. When HPR1018HA PE was blended with PE-LLD with a melt flow index of 1.0 g/10 min， the overall mechanical properties of the films decreased significantly with the increase of PE-LLD content， and their right-angle tear strength increased significantly.
YANG Lu, CHEN Hanting
Abstract (
640 )
PDF (4651 KB)(
584
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33 )
A self?assembled system was prepared using pure hydrophilic random copolymer poly（DMAEMA-co-AA） as a template， and its morphology and structure were investigated. Silver nanoparticles were then prepared by an in-situ reduction method， and their application in antibacterial packaging was studied. The results indicated that the pure hydrophilic random copolymer poly（DMAEMA-co-AA） could form the stable structures of microporous rod-like and rod?like secondary self-assembled systems in spherical or cubic shape at low pH value. With the increase of silver reduction rate， the silver nanoparticles disintegrated from the spherical or cubic shape to a small spherical shape. The logarithm antibacterial value of the antibacterial film was more than 4.5. The storage time of fruits at room temperature increased by more than 4 times after the silver nanoparticles were used for antibacterial packaging.
YU Yang, ZHAO Xinyu, HU Fuqiang, LIU Hai
Abstract (
862 )
PDF (2676 KB)(
620
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43 )
The reversible thermochromic polypropylene （PP） special materials were prepared by a two-step method. A master batch based on poly（ethylene-1-octene） （POE） and reversible thermochromic powder was first prepared by a miniature twin-screw extruder. The reversible thermochromic PP special materials were then prepared by melt blending PP with the resulting master batch. The effect of master batch content on the reversible thermochromic property， mechanical properties， thermal properties and microstructure of the prepared special materials were investigated. The results indicated that the reversible thermochromic powders were finely dispersed in the PP matrix because of the good compatibility between POE and PP matrix. The PP special materials exhibited an excellent reversible thermochromic property and high notched impact strength.
Kehong ZHANG, Xiaoran WANG
Abstract (
1128 )
PDF (3023 KB)(
772
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43 )
The poly（lactic acid） （PLA）-matrix composites were prepared by solution and melt blending methods using polyurethane （PU） as an impact modifier and nanocellulose （NCF） as a reinforcement agent. The effects of NCF and PU on the mechanical properties and heat resistance of the PLA/PU/NCF composites were investigated systematically. The structural characterizations and performance measures of the composites were carried out by Fourier?transform infrared spectroscopy， thermogravimetric analysis， scanning electron microscopy and mechanical property tests. The results indicated that the flexible PU molecules could inhibit the crystallization of PLA and therefore enhanced the toughness of PLA. On the other hand， the rigid NCF molecules could enhance the strength of PLA through hydrogen bonding. Compared to pure PLA， the tensile strength and elongation at break of the composites increased by 12.10 % and 694.91 %， respectively， when 3 wt% of NCF and 17 wt% of PU were added. Moreover， the addition of PU and NCF improved the high?temperature thermal stability of PLA significantly， and the composites obtained a residual carbon rate of 19.36 wt% at 600 °C.
LIU Yan, LU Zhehong, KANG Xinlong, FENG Weili, LIU Baoying, LI Jiantong, DING Tao, XU Yuanqing, FANG Xiaomin
Abstract (
1094 )
PDF (4591 KB)(
1001
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HTML (
39 )
Antimony trioxide （Sb2O3） was modified with a silane coupling agent （KH560）， and then the synergistic flame retarding effect of Sb2O3 and aluminum diethylphosphate （ADP） on polyamide 6 （PA6） was investigated. The chemical structure and thermal performance of modified Sb2O3 was characterized by Fourier-transform infrared spectroscopy and thermogravimetric analysis （TG）. The flame-retardant performance and relevant mechanism of PA6-based composites were analyzed by vertical burning test， limiting oxygen index， and cone calorimeter analysis， TGA， SEM and Raman spectroscopy. The results indicated that the modified Sb2O3 exhibited a better synergistic flame-retardant effect than pristine Sb2O3. The flame-retardant PA6 composites achieved a UL 94 V-0 classification and a LOI of 33.8 vol% at a modified Sb2O3 content of 2 wt% and a ADP content of 8 wt%.
FENG Shen, WEN Liang, SUN Zhaoyang, JI Yang
Abstract (
2787 )
PDF (2542 KB)(
1716
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83 )
A series of poly（glycolic acid） （PGA）/poly（butylene adipate-co-terephthalate） （PBAT） compounds at different mass rations were prepared by melt blending， and their heat resistance， mechanical properties and barrier properties were characterized. The results indicated that when the PGA/PBAT mass ratio was set to 80/20， the compounds achieved the tensile strength of 68.8 MPa， elongation at break of 72.15 %， impact strength of 16 kJ/m2， and the load thermal deformation temperature of 120 °C. These results suggested that the compound could be used to produce disposable tableware. When the PGA/PBA mass ratio was set to 20/80， the blown films processed by the compounds achieved the vertical and horizontal tensile strength of above 25 MPa and elongation at break of above 600 %. This indicated that the compounds could be used to produce film bag products. In addition， with the increase of PGA content， the compound exhibited a gradual increase in water barrier properties. For the compound at the PGA/PBAT mass ratio of 20/80， its water vapor transmission rate was just 1/7 of the value of pure PBAT films.
Processing and Application
FU Yunsong, WANG Ruohan, LI Ao
Abstract (
493 )
PDF (4577 KB)(
667
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30 )
Taking the dispersion experiment of pigments in polypropylene as an example， the heating effect of PID temperature control system of batch mixer in different environments was investigated. Based on the temperature control effect of mixer in closed room temperature environment， the corresponding fuzzy rules were constructed by a combination with the influence of PID parameters on the effectiveness of temperature control system. A fuzzy P?based temperature control system was then established by combining the fuzzy algorithm and PID algorithm. The temperature control system of ID algorithm and the establishment process were described in detail. The experimental results indicated that the fuzzy PID temperature control system could adjust the PID parameters in real time， effectively improved the heating efficiency of the mixer under the interference of external environment， and significantly improved the accuracy for the results of the pigment dispersion experiment.
ZHOU Jiang, PU Jiang, LI Kunfeng, YUAN Yukun, YIN Yufaning
Abstract (
591 )
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467
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29 )
A test bench for low and medium level radioactive waste packaging container was developed on the basis on the regulations for the safe transport of radioactive materials. A series of experiments including the free falling， penetration， stacking， sealing and spay tests were carried out for the test bench of the packaging container. The bench was equipped with an advanced non-contact full-field strain measurement system that can provide the measurement of full-field shape， the displacement data in 3D space for the experiment， and the analysis of the stress strain data. A verification experiment for a 3 m3 container was completed on this beach. The results indicated that the packaging container could meet the requirements of the design and relevant national regulations. The test bench developed in this work can be used for radioactive waste packaging containers. The results also provided the powerful data for the examinations by authority. The development of the test bench can improve the level of the radioactive solid waste container testing， and also provides an identification technical support for relevant manufacturers to develop low and medium level radioactive waste preparation containers or military packaging containers with independent intellectual properties.
WEI Chenjie, WANG Jifen, QIN Ge, DU Haoyu, MU Yilong
Abstract (
570 )
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597
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23 )
Middle infrared spectroscopy and chemometrics were adopted to identify the fragments of automobile bumpers. Two classification models， Fisher discriminant analysis and k-nearest neighbor algorithm， were established on the basis of the full-band spectral data， the spectral data of fingerprint region and the spectral data after the dimensionality reduction of principal component analysis of 52 vehicle bumper fragments. The comparison of classification results was also carried out. The results indicated that the classification model had higher classification accuracy when constructed by the principal component analysis that extracted the characteristic variables. The classification accuracy of polypropylene， polypropylene/talcum powders， polypropylene/talcum powders/calcium carbonate reached 92.3 %， and the classification accuracy of polypropylene/talcum powder obtained from 10 brand samples reached 88.9 %. This indicates an ideal classification result. In the two classification models constructed in this work， the classification rate of Fisher discriminant analysis model is much higher than that of the k?nearest neighbor algorithm model. It is believed that the k-nearest neighbor algorithm model is influenced by the imbalance of samples. The middle infrared spectroscopy combined with chemometrics can accurately distinguish the fragments of vehicle bumpers and therefore meets the requirement for rapid and nondestructive tests.
LEI Jingfa, WEI Zhan, LIU Tao , SUN Hong , DUAN Huantian
Abstract (
1541 )
PDF (5212 KB)(
1068
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HTML (
55 )
To analyze the static and dynamic mechanical properties of an additive manufacturing fused deposition molding material， poly（lactic acid） （PLA）， at low and high strain rates， MTS material testing machine and split Hopkinson pressure bar （SHPB） device were adopted severally to carried out the static and dynamic mechanical measurements at three printing speeds of 40， 80， and 120 mm/s under low-strain-rate and high?strain?rate loading conditions. The surface morphology of the prepared specimens was also observed. The results indicated that the elastic modulus and yield stress of PLA increased significantly with an increase of strain rate. Microscopic morphological analysis indicated that the PLA material exhibited fewer defects at a printing speed of 80 mm/s. At the same strain rate， the elastic modulus and yield stress of the material obtained at this printing speed were significantly higher than those at the printing speeds of 40 and 120 mm/s. The PLA material presented obvious elasticity and plasticity stages under the static load， and the plastic segment exhibited a strain-softening phenomenon. On the other hand， the PLA material showed significant viscoelastic characteristics under the dynamic load. The ZWT model was used to establish the viscoelastic constitutive model for the PLA material， and the fitting curve obtained from this constitutive model was in good agreement with the experimental curve.
Additive
LUO Tongtong, SUN Ling
Abstract (
968 )
PDF (4393 KB)(
804
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HTML (
40 )
PLA/PBAT/poplar powder （WF） composites were prepared by melt blending using poly（lactic acid） （PLA） and poly（butylene adipate-co-terephthalate） （PBAT） as matrices and WF as a filler. The standard test specimens were then prepared by a fused?deposition?modeling （FDM） technology. The effect of silane coupling agent （KH550） on the morphology， and rheological and mechanical properties of the composites was investigated with scanning electron microscopy observation， Fourier?transform infrared spectroscopy， rotational rheometer and mechanical test machine. The results indicated that the composites achieve an increase in tensile strength by 136 % at the coupling agent content of 3 wt%. The silane coupling agent could be covalently coupled with PLA and PBAT to form a grafted copolymer， and therefore the compatibility between two phases was improved. Meanwhile， the polycondensation reaction between the silane coupling agent and the hydroxyl group on the surface of WF could also effectively improve its compatibility with the PLA/PBAT matrix. As a result， the mechanical properties of the composites were greatly improved. The viscosity of the composites decreased with an increase of coupling agent content. When the content is 3 %， the wire achieved the optimum comprehensive printing performance at the coupling agent content of 3 wt%， resulting in an optimum quality for the printed products.
Plastic and Environment
MA Qiaoyun, WENG Yunxuan, ZHANG Caili
Abstract (
1249 )
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937
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44 )
This paper reported an investigation on the reaction mechanism and influence factors of the alcoholysis of poly（lactic acid） （PLA） catalyzed with ferric chloride（FeCl3）. The effects of reaction temperature， reaction time， and addition amounts of catalyst and ethanol solution on the alcoholysis reaction were investigated in detail. The chemical structure of the alcoholysis product was characterized with 1H-NMR， FTIR， and GPC. Furthermore， the degradation kinetics of the alcoholysis reaction was also explored. The results showed that the optimum process conditions were determined as a reaction temperature of 130 ℃， a reaction time of 24 h， a C2H5OH/PLA mass ratio of 3/1 and a FeCl3/PLA mass ratio of 3/40. Under the above optimum conditions， the alcoholysis reaction led to a depolymerization rate of 99.81 % and an ethyl lactate yield of 73. 60 wt% for PLA. It was found that PLA could be completely depolymerized into ethyl lactate under the catalysis of FeCl3， acting as a first-order reaction with a reaction activation energy of 10.28 kJ/mol.
Machinery and Mould
WANG Jing, LIU Xuemin, CUI Yubo
Abstract (
1065 )
PDF (6927 KB)(
148
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39 )
Aiming at the shell plastic parts with complex narrow and porous structure， we designed a type of mould structure with core pulling and secondary ejection through the back die insert. In this structure， the rear die insert was designed with a taper structure. Under the control of spring and limit pull rod， the rear die insert was pulled out from the plastic part at first， and then the second ejection action was completed by a thimble. Such a design successfully resolved the demolding problem in the complex， narrow and porous shell plastic parts. The die structure layout is reasonable， the mechanism design is ingenious， and the action is reliable. This structure is advantageous for the reduction of production and manufacturing costs and therefore can provide a useful reference for the design of molding die of similar plastic parts.
Review
LIU Penghui, YANG Huahao, HU Xiaoyi, ZHE Dongmei
Abstract (
1040 )
PDF (3484 KB)(
951
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41 )
This paper introduced the fracture mechanics theory and three relevant research methods， including the linear elastic fracture mechanics， elastic plastic fracture mechanics and essential work of fracture. The theoretical background and premise of these three methods， the test method and calculation process of material parameters， the effect of precrack on test results， and the research progress in the application of polymer materials in recent years were also briefly introduced. The application range and characteristics of these research methods and the specific practical effects were analyzed comparatively.
YANG Fukai, ZHANG Yudi, DENG Yuyuan, XU Xinyu
Abstract (
1039 )
PDF (2567 KB)(
1521
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47 )
This paper reviewed the properties of PI foam materials， including thermal insulation， flame retardancy， dielectric performance， sound absorption， electromagnetic shielding effectiveness， and mechanic properties. The mechanisms for the performance improvement of PI foam materials were summarized and analyzed， and the development direction in future was prospected.
ZHANG Xin, ZHOU Wen, QIN Wenbo, LIU Jinglong, GUO Bin, HUANG Yanan
Abstract (
857 )
PDF (3394 KB)(
956
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29 )
Forest Chemicals have non-toxic， ecologically friendly， renewable characteristics. It is of great significance to exploit their applications to make full use of forest resources and promote the sustainable development of economy. This paper systematically introduced the application and development of three forest chemicals， i.e. rosin， tannin extract and shellac， in plastics and composites. In the field of composites， rosin can be used as a matrix or a modifier， and tannin extract can be added directly or used after extracting the tannin. Moreover， shellac can be used as a surface modifier or a matrix for composites. The research trends in this field were finally prospected.
