GENG Xiaoling, ZHANG Zhijia, WANG Guojun, LI Wanli
Abstract (
458 )
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220
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An absorption resin with a high capacity for four organic solvents was prepared by suspension polymerization using octadecyl methacrylate, butyl acrylate and styrene as monomers, and the effect of crosslinker content on the saturated adsorption rate of the synthesized absorption resin was investigated. The experimental results indicated that the absorption resin achieved a maximum saturated adsorption rate at the crosslinker content of 0.25 wt%, and it presented a saturated adsorption time within 15 min for toluene, chloroform, n-hexane, and dichloromethane. The absorption resin presented the saturated adsorption rates of 23.18, 34.00, 15.86 and 22.20 g/g for toluene, chloroform, n-hexane and dichloromethane, respectively. The absorption resin exhibited excellent absorption performance.
ZHANG Jiarong, ZHUANG Jian, WU Daming, XU Hong, GAO Wangxin, SUN Jingyao
Abstract (
710 )
PDF (1027 KB)(
294
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To understand the preparation process and skin-puncturing effect of microneedles with stratified solubility for efficient use of lidocaine, the polymer microneedles were prepared by two casting methods using polydimethylsiloxane as a negative model and the polyvinyl alcohol/sodium hyaluronate/polyvinylpyrrolidone compound as a composite matrix. The morphology of the resulting polymer microneedles was observed by a microscope, and their height was measured. The puncturing test was conducted on the abdominal skin of a mouse, and then the puncturing effect of microneedles was investigated upon the obtained frozen sections. The experimental results indicated that the lidocaine-containing polymer microneedles achieved a formation rate of 100 %, and lidocaine was mainly distributed in the needle bodies of the microneedles at a height of 450 μm. The microneedles were able to penetrate the skin just after reaching the dermis layer by giving a channel with a depth of about 250 μm through the skin. In addition, 90 wt% of the needle bodies dissolved rapidly within 5 min, and the molding cycle was shortened within 4 hours.
WU Weili, LI Xiang
Abstract (
599 )
PDF (1932 KB)(
207
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In view of the faults of polypropylene (PP)fiber like insufficient tensile strength and low rigidity, the PP/high-density polyethylene (PE-HD)/graphene composite fibers were prepared by a melt-spinning method, and the effect of graphene on their properties was investigated by polarizing microscope, tensile experiment, scanning electron microscope, differential scanning calorimeter and Fourier-infrared spectrometer. The results indicated that the tensile strength of the composite fibers reached 2.46 GPa at the PE-HD content of 25 phr, which increased by 8 % compared to pure PP fiber. When 0.3 phr of graphene were incorporated, the composite fibers gained an increase in tensile strength by 1.6 % compared to the pristine PP/PE-HD fiber. The thermal stability of the fibers was also improved with the addition of PE-HD and graphene.
ZHU Yan, ZHANG Qifeng, JIA Shikui, ZHAO Zhongguo, CHEN Ligui, CAO Le
Abstract (
834 )
PDF (2839 KB)(
250
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Nanocellulose (CNF)was surface-modified by a silane coupling agent, KH550, and then a poly(butylene succinate)(PBS)/modified CNF masterbatch was prepared by melt blending with a twin-screw extruder. A series of poly(lactic acid)(PLA)/PBS/CNF blends were prepared by melt compounding with the obtained masterbatch, and their hygrothermal aging performance was characterized in a damp heat aging test chamber. The crystallization and mechanical properties of the blends were investigated by SEM, WAXD, DSC, polarizing microscope and universal testing machine. The results indicated that CNF could act as a nucleating agent to improve the crystallinity of PLA. The compatibility between the PLA matrix and PBS/CNF masterbatch was improved greatly due to the surface modification. The blends achieved an increase in degree of crystallinity by 28.15 %, in tensile strength by 5.54 % and in elongation at break by 8.23 % after aging for 36 h.
ZOU Zaiwang, CUI Yongyan
Abstract (
420 )
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198
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Five types of coppor ion complexes including copper acetylacetonate, copper salicylate, copper citrate, sodium copper edetate and copper oxalate were prepared by a hydrothermal method and then introduced into polyvinyl chloride (PVC)as a smoke-suppressing agent. The effects of these copper ion complexes on the smoke-suppressing, flame-retardant and mechanical properties of PVC were comparatively studied by using smoke densimeter, limiting oxygen index analyzer and electronic universal testing machine. The results indicated that these five copper ion complexes could enhance the flame-retardant and smoke-suppressing properties of PVC. The PVC compounds achieved an increase in notched impact strength by over 30 % when 6 phr of copper citrate or copper oxalate was incorporated, and however the addition of ethylenediamine tetraacetic acid copper sodium, copper acetylacetonate and copper salicylate reduced the mechanical properties of PVC.
CUI Linjie, XIA Chuanjun, HU Yasong, MING Pingdeng, CHEN Junying, HUANG Xia
Abstract (
566 )
PDF (1788 KB)(
250
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A type of novel organic-inorganic hybrid hydrogels were designed and synthesized by mixing the amino acids derived oligopeptides with 3-glycidoxypropyltrimethoxysilane (GPTMS). Considering the fact that the presence of closed cage POSS may result in unexpected swelling and biodegradability by silane condensation, hydrophilic carboxylized Pluronic was introduced to avoid the formation of POSS. Triethylamine (TEA) and carboxylized Pluronic were self-assembled into a supramolecular system with the aid of the intermolecular hydrogen bond and π-π stacking. Such a supramolecular system hindered the condensation polymerization of silane and disrupted the self-polymerization of GPTMS. The transversal and surface morphologies and chemical structure of the hybrid hydrogels were characterized by FTIR and SEM, their thermal degradability was characterized by TG, and their compression performance after aging for different time was measured by an electronic universal testing machine. The results indicated that the introduction of oligopeptides could hinder the self-condensation of GPTMS into the cage structure, and the epoxy groups of GPTMS reacted with the active hydrogen of TEA to form an organic network. The carboxylated Pluronic could help to form a supramolecular self-assembly system with TEA by the intermolecular force. Moreover, the self-assembled system exhibited a dependency of mechanical performance on the aging time, and it presented highest compressive strength of 8.6 MPa after aging for 24 h.
WANG Yong
Abstract (
560 )
PDF (2692 KB)(
428
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In this paper, a semi-interpenetrating (IPN)structural polydimethylsiloxane (PDMS)/polyvinylidene fluoride (PVDF)microporous membrane was prepared by a non-solvent induced phase separation method with tetraethyl orthosilicate (TEOS)as a crosslinking agent and then applied for the disposal of oil-in-water-type emulsified wastewater. The effect of operation conditions such as feed pressure, feed temperature and feed concentration on the separation performance of the membrane were studied. The experimental results indicated that the flux decreased with an increase of TEOS dosage, and however the oil removal efficiency was enhanced. Moreover, the flux was also improved with the increase of feed pressure, temperature and concentration, and the membrane achieved a maximum value of 31.93 L/m2·h in flux. The membrane exhibited an opposite trend in oil removal efficiency with the membrane flux, and its maximum efficiency reached 60.3 %.
安华亮, 信春玲, 乔林军, 何亚东, 闫宝瑞
Abstract (
481 )
PDF (1981 KB)(
173
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The injection of supercritical fluid in the microcellular injection-molding process is a vital procedure, and however the current gas injection system usually generates a gas surge at the beginning of gas injection, which seriously influences the preparation of the single-phase melt and reduces the performance of products. In light of a visual experiment, it is straightforward to prove that the gas surge phenomenon is ubiquitous under different pressure conditions, and therefore the relationship between the gas surge amount and the pressure condition could be obtained.
LEI Zhenkai, WANG Chui, ZHANG Xi, JING Weijie, ZHU Xingcheng
Abstract (
761 )
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230
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The content of carbon black in the drip irrigation belt was measured by thermogravimetry, and mass loss of each raw material in the drip irrigation belt was analyzed during the pyrolysis process. The preferred test parameters and conditions were obtained from the thermogravimetric method by comparison of the thermogravimetric results, which included a sample mass of about 10 mg and a nitrogen flow rate of 30 mL/min. Moreover, a step temperature elevation range were determined from room temperature to 500 ℃, holding at this temperature for 10 min and then to 900 ℃ at a heating rate of 20 ℃/min. There are several advantages for the thermogravimetric method, including strong operability, energy saving and environmental protection. However, there is a relatively large standard deviation in the test results of mass loss for the thermogravimetric method, resulting in relatively discrete test results.
KUANG Tangqing, ZHONG Luohao, XU Pan, FENG Qiang, PAN Junyu, LIU Hesheng
Abstract (
414 )
PDF (3284 KB)(
169
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PP/PA6 blends were prepared at four blending ratios using PP as a continuous phase and PA6 as a disperse phase, and the effect of PP/PA6 blending ratio on the tensile strength and microstructure of the pipes obtained by WAIM with PP/PA6 blends was investigated. The tensile experimental results indicated that the tensile strength of the pipes increased at first and then tended to decrease with an increase of PA6 content. The scanning electron microscopic observation showed that the PA6 phase was dispersed in both the near-wall and the near-water layers in a long strip or long slice shape with a large length/thick ratio, but it was dispersed in the middle layer as ellipsoids. There is an increase trend in the aggregation and growth of the dispersed phases in each layer with an increase of PA6 content. Polarizing microscopic observation showed that some small and dense crystals were formed along the flow direction at the near-wall and near-water layers, whereas the relatively larger crystals were distributed at the middle layer. Moreover, PP was found to only form one crystal form during the WAIM process, but two crystal forms were generated in the PA6 phase. The degree of crystallinity of PP domain at the near-water and near-wall layers was higher than that at the middle layer. The degree of crystallinity of PA6 phase increased with its weight fraction in the blends, while a high degree of crystallinity was maintained for the PA6 phase at the near-wall layer.
GUO Weican, HU Yurui, MIAO Cunjian, SHI Jianfeng
Abstract (
550 )
PDF (1316 KB)(
293
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During the electrofusion welding process of polyethylene pipes, the strength of electrofusion joint is mainly determined by the time elapsed during the diffusion entanglement stage of the polyethylene molecular chains at the interface between the sleeve and pipe. There is an relationship between the time and depth of the fusion zone extended to the inside of the pipe. To explore the relationship between the depth of the fusion zone and welded joint performance, a depth measurement method for the fusion zone was proposed by means of ultrasonic technique, and a series of experiments were carried out for the depth measurement of the fusion zone in the pipe as well as the joint performance characterization. The experimental results indicated that the depth of fusion zone was related to the interfacial welding strength. When the depth was controlled within a certain range, the basic peeling strength and interface ductility could be obatained. On the basis of these results, a new method was proposed to determine the welding time of the electrofusion joint in terms of measuring the depth of fusion zone. Furthermore, the deviations caused by various factors such as temperature, welding voltage and wire resistance were fully considered to make this new method more suitable for practical engineering applications.
WANG Yiming, DU Yonggang, YANG Mingming, WANG Li, ZHUANG Xiangjie
Abstract (
488 )
PDF (1387 KB)(
185
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A series of bio-base plasticizers with different molecular structures were prepared by the reaction of 2,5-furan-dicarboxylic acid with trans-2-hexenol and n-hexanol. The effects of the molecular structure and amount of plasticizers on the mechanical and rheological properties of PVC compounds were investigated by means of impact test, tensile test, dynamic mechanical analysis and capillary rheometer. The results indicated that the impact strength of PVC compounds were improved with the addition of two new bio-base plasticizers, and 2,5-dihexyl furan-dicarboxylate exhibited a better plasticizing effect on PVC than 2,5-di-(trans-2-hexene furan-dicarboxylate)ester. When 10 phr of 2,5-dihexyl furan-dicarboxylate was added, the PVC compound obtained an increase in impact strength by 0.28 kJ/m2 but a decrease in tensile strength by 4.2 MPa compared to the compound containing the same content of dioctyl phthalate.
JI Haifeng, SONG Danyang, YAN Yushuang, WANG Weidong
Abstract (
498 )
PDF (777 KB)(
167
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In this work, a complex hindered phenol antioxidant, (2-Hydroxy-3-tert-butyl-5-methylbenzyl)-4-methyl-6-tert-butylphenyl-diphenylphosphite］,was synthesized by using diphenyl-phosphonium chloride and 2,2′-methylenebis-(4-methyl-6-tert-butylphenol)as raw materials, and a yield of 65.12 % was achieved from the synthetic process. The molecular structure of the obtained product was characterized by FTIR and then confirmed to be in accordance with the configuration design. A comparative investigation on the thermal stability and scavenging capability for DPPH free radical was carried out between the synthesized product and a commercial antioxidant, 2,6-di-tert-butyl-4-methylphenol (BHT). The results indicated that the synthesized product had a higher molecular weight and better thermal stability than BHT, and it exhibited a good scavenging effect on DPPH free radical, indicating a better antioxidant capability compared to BHT.
ZHAO Lei, JIANG Weiqing, LIU Hua, LI Guifu, ZHOU Hongtao
Abstract (
567 )
PDF (1546 KB)(
164
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The phloem fiber obtained from alchornea davidii franch (PF-ADF)was prepared by a physicochemical combination method and then treated with alkali and a coupling agent (A-151). Three types of biodegradable PBS composites reinforced with PF-ADF were prepared at the PBS/fiber weight ratio of 80/20. The effect of surface treatment on the microstructure and physical properties of the fibers as well as the mechanical properties of the composites were investigated. The results indicated that most of the non-cellulosic substances like pectin were removed from the surface of PF-ADF after treatment. The surface of PF-ADF exhibited some “S” shape grooves after treated with alkali, and however the grooves on the surface of PF-ADF treated with the coupling agent showed a good continuity and a large depth. The PF-ADF achieved an increase in tensile strength by 5.08 % but a decrease by 3.58 % after treatment with alkali and coupling agent, respectively. Compared to pure PBS, the composites gained an increase in tensile modulus by 48.32 % and in bending strength by 25.97 %. Moreover, their tensile and bending moduli were improved by 146.45 % and 128.3 %, respectively. The three types of the composites exhibited a similar trend in biodegradation, and the composite with the surface-treated PF-ADF showed a smaller weight-loss rate compared to the other two composites.
TANG Dingde, TIAN Ke
Abstract (
440 )
PDF (3484 KB)(
222
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Aimed at the difficult mold design problem of unmanned aerial vehicle (UAV) blade plastic parts, which have special shape and difficult demoulding, the CAE analysis is used to determine the moulding and pouring scheme. Then, on the basis of the comparative analysis of the two demoulding schemes, a simplified two-plate mould is selected and designed for injection moulding, which effectively reduces the cost of mould manufacturing. In the Mould, the blade part of the plastic part is formed by the main part of the simplified two-plate Mould, which ensures the quality of the blade. The mortise and tenon part of plastic parts is moulded and demoulded by a new three-stage demoulding mechanism, which consists of two sub-mechanisms, one is movable seat plate mechanism and the other is compound mechanism of slider and ejector. When the mechanism demoulds, the first demoulding is carried out by means of the opening power of the mould, and the second side core pulling is carried out by means of the T-block driven by the cylinder. Mold, using the continuous ejection of the cylinder to drive the ejector pin to eject the plastic part completely from the side core. The mechanism design is ingenious and the Mould structure is simple, which can effectively reduce the manufacturing cost of the Mould.
LI Hailin, WANG Jinhong, DING Ligang, ZHAO Yonghao
Abstract (
322 )
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156
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In this paper, the structural manufacturability of special-shaped composite products was introduced by using the plastic robot products as carriers, and the forming scheme of one mold with many different cavities was determined. Based on the CAE numerical simulation technology, the design of the mold gating system was optimized to resolve the unbalanced filling problem occurring in the flow passage. Meanwhile, a special structure was additionally arranged on the runner to solve the problem of space storage for the products after injection molding production. According to the functional requirements of the products, a core pulling mechanism was arranged in the mold to solve the technical problem of thread clamping after the product was formed. The mold achieved good results in the actual production process. This work provided a good reference for the design of similar molds.
HOU Lianlong, TANTAI Jianli, JIA Shaowei
Abstract (
469 )
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236
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This paper introduces the structure, characteristics, main raw materials, economy and market applications of thermal insulation plastic pipelines, which are mainly used to replace the steel pipelines in the centralized secondary network for district heating systems. The caliber of these pipelines usually has a diameter lower than 400 mm and is used at a temperature lower than 80 ℃. By reviewing the use of raw materials, application process and industry development of thermal insulation pipelines, the paper summarized the new development of the plastic pipelines. The thermal insulation plastic pipelines are expected to be applied for the primary heating pipe network, steam transportation, thermal insulation and high-pressure transportation.
YE Xuan, TU Huajin
Abstract (
703 )
PDF (1109 KB)(
333
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This paper briefly introduced the 3D printing and fused deposition molding technologies and also mentioned the problems in the acrylonitrile-butadiene-styrene copolymer (ABS)materials used for 3D printing. Furthermore, the ingredients, preparation technology, 3D printing processing, performance and applications of ABS materials used for the 3D printing were discussed. It is important for researchers to make effort to improve the mechanical performance of 3D printed products with the ABS materials as well as to endow them with more special properties so as to extend the application range of ABS materials for 3D printing.
