HE Xiaoqian, ZOU Wei, WANG Hong, LI Chao, ZHANG Chen
Abstract (
767 )
PDF (971 KB)(
231
)
A type of flexible epoxy resin was synthesized by a two-step reaction, in which isophorone diisocyanate was first reacted with the hydroxyl group of epoxy resin to obtain a modified epoxy resin with the —NCO side groups and then polypropylene glycol (PPG) was grafted onto the side chains of the modified epoxy resin through the reaction between the hydroxyl groups of PPG and the —NCO groups on the modified epoxy resin to obtain polyether-grafted epoxy resin (PPG-g-EP) with different molecular weights (PPG400, PPG1000 and PPG2000). The structure of the resultant PPG-g-EP was characterized by titration and FTIR. The thermosetting PPG-g-EP was further prepared by using polyetheramine as a curing agent, and its mechanical properties were measured by a universal testing machine. The results indicated that the thermosetting PPG-g-EP with a longer PPG chain achieved higher elongation at break, and the PPG2000-modified epoxy resin gained the maximum elongation at break of 98 %.
ZHAO LeiWANG ShanshanJIANG Wenzheng, LIU Wenfang, ZHANG Wenbiao
Abstract (
504 )
PDF (1197 KB)(
167
)
The bamboo charcoal (BC)-reinforced polypropylene composites were prepared by a meltblending method, and the effect of BC content on the electrical conductivity of the composites was evaluated. The results indicated that the addition of BC reduced the volume resistivity of the composites significantly, and the electrical conductivity exhibited a higher growth rate especially with the addition of BC over 30 wt%. Moreover, the morphology, water absorption, apparent porosity, mechanical properties and thermal stability of the composites were also investigated.
JIANG Niu, XU Zihang, HU Yuexin, HAN Xiangyan, LIU Zhongquan
Abstract (
635 )
PDF (925 KB)(
136
)
In this work, the structural difference of two types of bimodal high density polyethylene resins (FHM 9455F1-A and FHM 9455F1-B) with different mechanical properties used for films was investigated by means of differential scanning calorimeter, high temperature gel permeation chromatograph and rotational rheometer. The FHM 9455F1-A resin exhibited higher impact strength and tensile strength than the FHM 9455F1-B one. The results indicated that the FHM 9455F1-A resin had a higher relative content in the higher molecular weight fraction, which resulted in the formation of more tie molecules between the lamellas. This result improved the impact strength of PE resins. In addition, the lamella thickness, especially for the thicker lamella contributed to higher tensile strength for the PE resins.
SHI Pengxiang, ZHANG Jianbang, WANG Yandong, WANG Jie, YU Shouwu
Abstract (
644 )
PDF (1187 KB)(
148
)
An intumescent flame retardant (IFR) was prepared by mixing a hyperbranched triazine charring agent with ammonium polyphosphate at a mass ratio of 1∶1 and then used for the flame retardancy of polypropylene (PP). The mechanical and flame-retardant properties of the resulting flame-retardant PP are evaluated by means of impact and tensile measurements, LOI test and vertical burning experiment, and the cross-section morphology was observed by SEM. The characterization results indicated that the impact strength of flame-retardant PP increased first and then tended to decrease with an increase of IFR content. However, the tensile strength exhibited a continual decrease with increasing the content of IFR. The flame-retardant PP containing 15 % IFR achieved a UL 94 V-0 classification, implying an excellent flame retardant effect.
WANG Han, LIU Feng
Abstract (
1127 )
PDF (1506 KB)(
276
)
A series of poly(phenylene oxide) (PPO) resins with different low molecular weights were prepared by using the high-molecular-weight PPO, and their molecular weights were monitored by GPC during the synthetic process. Furthermore, the chain-growth mechanisms in the polymerization process were studied systematically. The investigation results indicated that the redistribution and rearrangement mechanisms did not always exist simultaneously in the process of chain growth. The process could be divided into the following three stages: redistribution chain growth, rearrangement and redistribution chain growths and dynamic equilibrium of redistribution. The molecular-weight control of the synthesized PPO could be reasonably explained by a combination of productivity and GPC characterization for the chain growth. This work opens up a new insight into the study of chain-growth mechanisms.
YU Haomiao, CHEN Yanming, WANG Liyan, WU Quancai
Abstract (
521 )
PDF (1252 KB)(
150
)
A type of PBT-based copolyester was synthesized by using terephthalic acid and 1,4-butanediol as base materials and 1,4-cyclohexanedimethanol (CHDM) as a comonomer, and its rheological properties were measured by capillary rheometer and rotary rheometer. The results indicated that the resultant copolyester exhibited a pseudoplastic non-Newtonian fluid behavior with a non-Newtonian index less than one. The dynamic viscosity of the copolyester was found to increase with the incorporation of CHDM.
WANG Yong
Abstract (
500 )
PDF (1500 KB)(
139
)
A series of poly（vinyl alcohol）(PVA)/hyperbranched polyester (HBPE) crosslinked membranes were prepared by blending PVA and HBPE at different mass ratios, and their dissolution-diffusion mechanism and pervaporation properties were investigated. The results indicated that the water permeability coefficient of the crosslinked membranes increased at the elevated temperatures, and its variation trend was consistent with the water flux. The crosslinked membranes achieved a maximum water permeability coefficient of 71.952 g/m2·h at 55 ℃. The water flux was found to increase with an increase of HBPE content, and a maximum water flux of 185.726 g/m2·h was gained for the crosslinked membranes containing 40 wt% HBPE.
GONG Wei, LI Meilan, SHI Ming, WEI Jia, ZHANG Guochun, LIU Bailing
Abstract (
524 )
PDF (1546 KB)(
239
)
According to the structural design insight into a material, a poly(AA-co-SSS-co-PPGAZMA) copolymer was successfully synthesized by solution polymerization, and its structure were characterized by FTIR. The resultant poly(AA-co-SSS-co-PPGAZMA) copolymer was applied for the scale inhibition of industrial circulating cooling water. The effects of the molecular weight of poly(propylene glycol) (PPG), monomer ratio, dosage of scale inhibitor and pH value on the inhibition efficiency of CaCO3 scale were studied intensively. Furthermore, the effect of scale inhibitor on the crystalline structure of CaCO3 was investigated by XRD and FTIR. The results indicated that the poly(AA-co-SSS-co-PPGAZMA) copolymer exhibited a good inhibition effect on CaCO3 scale, and it achieved a inhibition rate of 95.12 % for the CaCO3 scale at the PPG molecular weight of 800, the PPGAZMA/AA/SSS mass ratio of 1/2/1 and the scale inhibitor dosage of 3.5 mg/L. Moreover, The XRD and FTIR analyses indicated that the scale inhibitor could inhibit the growth of CaCO3 crystals and reduce the crystallinity of CaCO3 scale, and therefore reached the purpose of scale inhibition.
LI Lingli, HUANG Aijun, ZHANG Yan, JIANG Jianqiang
Abstract (
719 )
PDF (1110 KB)(
204
)
Thermal conductivity is an important index for evaluation of the thermal insulation performance of thermal insulation materials. The thermal conductivity of extruded polystyrene (XPS) boards with different surface structures was investigated. The results indicated that the thermal conductivity of XPS boards with a grooved surface was slightly influenced by their surface structure. There is a fair structural influence on the thermal conductivity of XPS boards with the one side removed from the skin. However, the thermal conductivity of the XPS board with the doublesides removed from the skin was reduced significantly.
ZHENG Yinglei, SUJin, LI Yu'e, ZHE Dongmei
Abstract (
333 )
PDF (1211 KB)(
177
)
In this paper, according to the standard ASTM D2992-12 titled “glass fiber (reinforced thermosetting resin glass fiber) pipe and pipe fittings for hydrostatic design basis”, a method B was adopted to investigate the long-term hydrostatic performance of filament-wound-reinforced composite pipes. The basic principles for this test method were introduced and the obtained results were analyzed. Based on the analysis and evaluation, the composite pipes achieved a 50-year long-term hydrostatic pressure of 14.3 MPa.
TAN Anping, LIU Kewei
Abstract (
560 )
PDF (2480 KB)(
178
)
In order to predict and reduce the warpage risk, Moldflow software was adopted to analyze and predict the warpage deformation of an injection-molded part before the die design and manufacturing. Taking the warping deformation of automobile glove box cover as a quality evaluation objective, three main factors for warpage deformation, including orientation effect, uneven cooling and uneven shrinkage, are optimized one by one. In the case of die structure, the adjustment of gate position and cooling system could make the warpage deformation decrease significantly. As for the optimization of processing conditions, we conducted an orthogonal experiment with four process parameters, which included the melt temperature, die temperature, holding pressure and holding time. The influence of each process parameter and the optimum process plan were obtained by range analysis. After further optimizing the holding curve of the scheme, the influence level for each process parameter was obtained. The warpage deformation could be further reduced to form the final scheme. The practice production proved that the CAE numerical simulation could provide a good guidance for the design of die and reduce the number of die repair and the probability of die scrap significantly.
LI Hao
Abstract (
2193 )
PDF (1421 KB)(
404
)
This article analyzes the reasons of white and transparent flow lines generated during the film blowing processing, offers solutions to avoid flow line in terms of processing tehcnics and die designing. Optimizing the design of spiral-mandrel-type die head by simulation analysis with rheological theory, to reduce and diminish the flow lines and meet the requirement for higher processing and experimental standards.
WANG Chuansheng, ZHANG Wei, JIANG Rui, MA Yabiao, BIAN Huiguang, CHAO Yuqi
Abstract (
565 )
PDF (1809 KB)(
193
)
Combining with the existing feeding extrusion methods of extruders, a new 3D printing method for the blends of industrial ceramics-polymer was developed. According to the optimum mixing formula of industrial ceramics-polymer, the printing experiments were carried out with a self-designed new screw extrusion 3D printer. The four factors of feeding temperature, nozzle temperature, extrusion speed and forming platform temperature were taken as experimental variables. According to the orthogonal experiment, the blank of the experimental model was printed out. Finally, according to the surface accuracy and forming mass of the model blank, the optimum 3D printing process of blends of industrial ceramics-polymer was determined.
WANG Yanning, JIN Jiangbin
Abstract (
625 )
PDF (1838 KB)(
153
)
The poly(lactic acid) (PLA)/poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) blends were prepared by a melt-blending method using a chain extender (TMP-6000) as a compatibilizer. The effect of TMP-6000 on the crystallization behavior, microstructure and mechanical properties of PLA/PHBV blends was investigated. The DSC analysis results indicated that the addition of amorphous PLA prevented the crystallization of PHBV and depressed the crystallinity of the blends. However, the cold crystallization temperature of PLA was improved. The cold crystallization peak of PLA domain tended to disappear for the blends with 0.5 wt % TMP-6000. The glass transition temperature of PHBV phase increased with the addition of an appropriate amount of TMP-6000. The morphological observation indicated that PHBV was dispersed homogenously in the PLA matrix in the presence of TMP-6000, and an optimal compatibility was achieved for the blends with the addition of 0.7 wt % TMP-6000. Moreover, the addition of TMP-6000 increased the molecular weight of PLA/PHBV blends significantly. The interface adhesion and tensile strength of the blends were enhanced due to the introduction of TMP-6000, and however the elongation at break decreased slightly.
YAN Guangyu, XU Ge
Abstract (
439 )
PDF (1578 KB)(
162
)
Two types of lignins were obtained from alkaline pulping black liquors by acidulation using nitric acid and sulphuric acid, and their particle-size distributions were analyzed. A comparative investigation was conducted for the properties of ethylene-propylene-diene-monomer (EPDM) rubbers with the two types of lignins and silane-coupling agent. The results indicated that the two types of lignins exhitibted a smaller value of D50 and a bigger specific surface area. The incorporation of lignin-coupling agents improved the mechanical performances of EPDM rubber more significantly than the silane-coupling agent. The tensile strength, elongation at break and hardness of EPDM rubbers increased by 21.42 %, 22.55 % and 8 degree with the addition of 1.5 phr nitrate lignin (based 100 g rubber). The Fourier-transform infrared spectroscopy (FTIR) analysis and scanning electron microscopic (SEM) observation indicated that the lignins played a role in the reinforcement of EPDM rubber. Thermogravimetric analysis revealed that the lignins and silane-coupling agents improved the thermal stability of EPDM rubbers. The lignins could be used to replace the silane-coupling agent for modification of EPDM rubbers in a cost-effective way and therefore exhibited good application potential.
LI Hongyan, WANG Weiwei, LIANG Bei, BIAN Ping
Abstract (
474 )
PDF (3018 KB)(
240
)
Aiming at the difficulty in mold design for the complex shape of plastic parts, we reported a design for the injection mold with one mold, one cavity and three plates. A two-layer parting mode and a 3-point gating system were adopted for the plastic parts. Aiming at the requirement for the mufti-feature and multi-purpose demolding of plastic parts, six slider core-pulling mechanisms and three inclined top mechanisms were designed to conduct the demolding action. In the slider core-pulling mechanism, the slider-driving mode in the slider mechanism was modified to the external spring-driving one, and the oblique core-pulling mechanism was modified to the horizontal slider driving tunnel slider oblique core-pulling mode. Such a design effectively reduced the excessive structural size requirements of the mechanism to the die, and therefore reduced the manufacturing cost and overcame the difficulties in processing and assembly. A new type of oblique-top mechanism with a front die was designed, in which a spring was used to drive the oblique-top rod to eject the plastic parts from the cavity. This design realized the side core pulling and demolding in the front die with the characteristics of bending hook and hole. The mechanisms designed by this work are simple and feasible for the injection mold, and their working reliability is high. Our design effectively simplifies the overall structure of the mold and makes the processing and manufacturing much easier.
YANG Bo, ZUO Xiaofeng, WANG Zhigang, HE Jianjun, HUANG Guojia, HE Jiaping
Abstract (
431 )
PDF (1725 KB)(
205
)
In this paper, we analyzed the correlation between the slow crack propagation of PE and the single/multiple microstructural parameters including the number of molecular chains, molecular weight and distribution, content and distribution of short-chain molecules, and lamella thickness. Many studies indicated that the molecular weight and its distribution, content and distribution of short-branched chains exhibited a more significant correlation with the SCG resistance of PE pipes than other single microstructural parameters. The SCG resistance of PE pipes could be well measured with the structural parameters consisting of the multiple microstructural parameters.
XU Chao, ZHANG Zhao, LIU Peng, LIU Zhen, WANG Qingzhao
Abstract (
539 )
PDF (3056 KB)(
301
)
The technical status and application research progress of various insulation materials and insulation pipe structures in China and abroad were reviewed; The thermal insulation properties, mechanical properties and microstructure of different thermal insulation materials were analyzed,including solid insulation materials, inorganic and organic foam materials, composite insulation materials and phase change energy storage materials;introduced the processing technology and structural design of oil pipelines of various structures,including tube tube structure, single wall tube, technical tube system and composite insulation hose.The application and development of the materials and structures of the current insulated pipelines were discussed.
