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2015, Volume 29 Issue 11 Publication date: 26 November 2015 Previous Issue Next Issue

Research Progress on Tetrazolyl Polymer

2015, 29 (11): 1-6 ; DOI: 10.19491/j.issn.1001-9278.2015.11.001

Abstract ( 651 )

This article mainly introduced the synthesis methods of tetrazolyl polymer，including cycloaddition reaction method,free radical polymerization, and functional group reaction method. The application of tetrazolyl polymer in energetic material and membrane material was introduced. Tetrazolyl polymerhas advantage of high energy and low sensitivity in energetic material. Tetrazolyl polymer not only has conductivity but also can be applied in the environment at high temperature and without water.

Research Progress in Charring Agents in Flame Retardants

2015, 29 (11): 7-16 ; DOI: 10.19491/j.issn.1001-9278.2015.11.002

Abstract ( 560 )

Composition and flame retardant mechanism of intumescent flame retardants (IFRs) were introduced in this paper. The research progress of the charring agents was reviewed. The flame retardancy of pentaerythrotol, triazine and other charring agents was summarized. The challenges of triazine charring agents and development directions in the future were also analyzed.

Evaluating Methods of Hindered Phenolic Antioxidants in Polyolefins

2015, 29 (11): 17-26 ; DOI: 10.19491/j.issn.1001-9278.2015.11.003

Abstract ( 626 )

Progress in evaluating methods of hindered phenolic antioxidants in polyolefins was summarized. The evaluating methods included differential scanning calorimetry, infrared spectrometry, chemiluminescence spectroscopy, and chromatography, etc. The limitations and main problems of each evaluation method were pointed out, which provided a reference for evaluation of hindered phenolic antioxidants in relatively complex systems, and qualitative and quantitative analysis of hindered phenolic antioxidants in polyolefins.

Effect of Carbon Nanotubes Surfacemodified by Melamine on the Flame Retardancy of Polypropylene

2015, 29 (11): 26-30 ; DOI: 10.19491/j.issn.1001-9278.2015.11.004

Abstract ( 1016 )

MWNTs were surface modified by grafting melamine resulting in MEL-MWNTs, which were characterized by FTIR and thermogravimetric analysis (TGA). The contribution of MEL-MWNTs on improving flame retardancy of PP was investigated through limit oxygen index, vertical burning (UL 94), cone calorimeter (CONE), and TGA. The composite morphology was observed by SEM, and mechanical performance was also analyzed. By addition of 3.0 wt% MEL-MWNTs in PP, the limit oxygen index of PP increased from 18 % to 22 %, and the time to the first dripping prolonged from 3.7 s to 30.0 s. Heat release rate was reduced and a compact char layer was formed during combustion of the sample containing MEL-MWNTs. The tensile strength was increased slightly, but elongation at break was decreased by incorporation of MEL-MWNTs.

Nucleating Agent and Ethylene-maleic Anhydride Copolymer Modified Glass Fiber Hybrids Reinforced Polyamide Composites

2015, 29 (11): 31-38 ; DOI: 10.19491/j.issn.1001-9278.2015.11.005

Abstract ( 564 )

Modified glass fiber (GF) was prepared through electrostatic absorption method and compounded with polyamide 66(PA66) by a twin-screw extruder. Scanning electron microscopy (SEM) images of the fractured and etched surfaces demonstrated that the presence of P22 on GF surfaces could induce the crystallization of PA66 molecules. The anhydride group of EMA could react with the amino group at the end of PA66 molecule chain leading to the adhesion of PA66 on GF surface. Thus a better interfacial adhesion between GF and PA66 matrix was obtained. The interlaminar shear strength and dynamic storage modulus (25 ℃) of PA66/GF-P22, PA66/GF-EMA, and PA66/GF-EMA-P22 composites increased by 18.3 %, 25.4 %, 32.4 % and 15.4 %, 24.1 %, 34.9 % based on those of PA66/GF composites, respectively.

Property Research and Selection of Wear-resistant Materials for Railway Bridge Bearings

2015, 29 (11): 38-42 ; DOI: 10.19491/j.issn.1001-9278.2015.11.006

Abstract ( 673 )

Two railway bridge bearing composites based on ultra-high molecular weight polyethylene (PE-UHMW) and polytetrafluoroethylene (PTFE) were prepared and their mechanical properties, heat-resistance, heavy load-bearing capacity, and wear-resistance were compared. It was found that the notched impact strength, tensile strength, flexural strength, and compressive strength of PE-UHMW composites were better than those of PTFE counterpart. The thermal conductivity of PE-UHMW composites was 0.58 W/(m·K), which was 223.1 % of that based on PTFE. The creep rates of PE-UHMW composites under a pressure of 90 and 190 MPa for 24 hours were 47.1 % and 81.4 % of those based on PTFE, respectively. Found in an abrasion test of 50 km, the line wear rate of PE-UHMW composites was only 7.4 % of that based on PTFE.

Polymerization of High Impact ABS Resin by Plug Flow Tube Continuous Reactors

2015, 29 (11): 43-49 ; DOI: 10.19491/j.issn.1001-9278.2015.11.007

Abstract ( 495 )

A plug flow reactor was used to prepare high impact acrylonitrile-butadiene-styrene copolymer (ABS) resin by continuous bulk polymerization. The effect of microstructure, the viscosity of the solution, the type of composition of the rubber on the impact strength of ABS resin was investigated. The optimized toughening system was found. When the feed ratio of the rubber was 9.0 % and the synthetic adhesive ratio was 55AE∶35AE=2∶1, the Izod notched impact strength of the samples was 351.3 J/m, which was better than that of marketed products.

Processability of PVC/Liquid Polymer Modified CaCO₃ Composites

2015, 29 (11): 50-54 ; DOI: 10.19491/j.issn.1001-9278.2015.11.008

Abstract ( 499 )

CaCO3 was coated with a liquid polymer modifier leading to molecular modified CaCO3 composites (CLCC), which was introduced into PVC. The processability of PVC/CaCO3 and PVC/CLCC systems were investigated by using torque rheometer, whiteness test, and UV-vis spectrophotometer. It was found that the CLCC particles had fine plasticization effect on PVC, and could restrain the decomposition of PVC resin during melting process. The whiteness retention of PVC/CLCC was higher than that of PVC/CaCO3 systems.

Synthesis and Characterization of ABS/Modified Kaolin Composite Materials

YU Shengping, SONG Haifeng, SHI Yangyang, XU Gewen, HUANG Yiping

2015, 29 (11): 55-60; DOI: 10.19491/j.issn.1001-9278.2015.11.009

Abstract ( 181 )

Preparation and Properties of Phenolic Resin/Silver Nanoparticles Plating Carbon Fiber Thermal Conductive Composites

2015, 29 (11): 61-65 ; DOI: 10.19491/j.issn.1001-9278.2015.11.010

Abstract ( 654 )

Silver plated carbon fiber (Ag-CF) was prepared by chemical plating and mixed with phenolic resin forming thermal conductive composites by the stirring and mixing method. The morphologies and properties of the composites were studied by scanning electron microscope（SEM）, energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). It was found that a large number of Ag nanoparticles covered the surface of carbon fiber. Thermal conductivity and mechanical properties of phenolic resin/Ag-CF composites increased with increasing Ag-CF content. When the content of the Ag-CF was 7.0 wt%, the thermal conductivity, impact strength, and flexural strength were 1.25 W/(m·℃), 66.7 kJ/m2, and 139.2 MPa, respectively. The temperature for 30 % residual ratio was 500℃, which contrast to 450 ℃ for neat phenolic resin.

Preparation and Properties of Self-cleaning PVDF/PMMA Membrane by Chemical Bath Deposition

2015, 29 (11): 66-70 ; DOI: 10.19491/j.issn.1001-9278.2015.11.011

Abstract ( 591 )

Micro-nano rough structure was constructed on PVDF/PMMA membrane by hydrophilic modification with NaOH solution and chemical bath deposition with alkylchlorosilane, which rendered the membrane with super hydrophobicity. It was found that the hydrophilic modification promoted the chemical bath deposition of alkylchlorosilane on the surface of PVDF/PMMA membrane. The optimum conditions for hydrophilic modification was 40 percent NaOH, at 70 ℃ for 60 min. The contact angle of the membrane reached 154.6(°). The self-cleaning test showed that dust could be removed by water from the membranes surface at an angle of 1(°).

Study on Mixing Performance of Chaotic Rotors in Two-rotor Continuous Mixers

2015, 29 (11): 71-77 ; DOI: 10.19491/j.issn.1001-9278.2015.11.012

Abstract ( 489 )

A chaotic mixing rotor was proposed, on which three-dimensional non-Newtonian isothermal flow field simulation was performed by means of Polyflow software to characterize the mixing performance in a two-rotor continuous mixer. The mixing process experienced by the material was statistically analyzed by particle tracking analysis (PTA) method. The influences of rotor structure and processing parameters on the mixing performance was also been discussed. Additional mixing experiments were conducted to evaluate and characterize the mixing performance of different rotor structures. It was found that the distributive mixing capability of high-chaos rotor was better than that of classical rotors, while the dispersive mixing capabilities of the two kinds of rotors were the same. The mechanical property of blends prepared by chaotic rotors was better than prepared by classic rotors. Both dispersive and distributive mixing capability would be promoted when the rotor speed increased. Besides, appropriate feed speed was also a key factor to achieve a good mixing performance. Key words：two-rotor continuous mixer; chaotic rotor; numerical simulation; mixing performance.

Simulation Analysis of Thin-walled Light Guide Plates of Polycarbonate at High Injection Speed

2015, 29 (11): 78-82 ; DOI: 10.19491/j.issn.1001-9278.2015.11.013

Abstract ( 573 )

Good performance of thin-walled light guide plates could be obtained with high injection speed. A model of guide light plate was established to explore the injection molding of thin-walled light guide plate with high injection speed. The rheological behavior of polycarbonate under high shear rate was analyzed with Moldflow, and the melt temperature variation in the mold cavity under different injection speed, plasticizing temperature, and mold temperature was discussed. Simulation showed that the shear rate within a certain range, the melt temperature in the cavity increased with increasing injection speed. Once the shear rate exceeded a critical value, the temperature began to decrease due to the presence of wall-slip. For the practical molding process, better filling could be obtained within the injection speed rang of 600 to 1000 mm/s. The plasticizing melt temperature would be decreased by about 10 ℃, and injection pressure was decreased by 50 MPa.

Analysis on Different Resins in Injection Based on Flow Simulation of Moldflow

2015, 29 (11): 83-86; DOI: 10.19491/j.issn.1001-9278.2015.11.014

Abstract ( 57 )

Effects of Injection Molding Process on Angular Deviation of Curved Transparent Polycarbonate Parts

2015, 29 (11): 87-91 ; DOI: 10.19491/j.issn.1001-9278.2015.11.015

Abstract ( 628 )

The effect of injection molding parameters, observation azimuth angle, and pitching angle on the angular deviation of curved thin transparent polycarbonate product was analyzed. Mediate screw speed, higher back pressure（4 MPa）and lower scrap quantity were favorable for plasticizing melt. Higher injection melt temperature above 285 ℃ and mold temperature above 90 ℃ in sured flowability and molecular relaxation resulted in homogeneous microstructure with lower deviation angle. Longer packaging rendered better optical product with denser and lower stress, however, too high packaging pressure may induce flow trace. Deviation angle below 8′ was suitable for transparent products.

Plasticization of Low Molecular Weight PBA on Poly(vinyl chloride)

2015, 29 (11): 92-96 ; DOI: 10.19491/j.issn.1001-9278.2015.11.016

Abstract ( 724 )

A series of low molecular weight polybutylene adipate (PBA) with different intrinsic viscosity was prepared from adipic acid and 1, 4 butanediol by melt polycondendation, which was introduced into PVC as a plasticizer and compared with DOP. The plasticization and the flame retardant of the PVC samples were studied by DSC, tensile tester, limited oxygen index, and the liquid phase migration. When 30 phr PBA was added, the Tg of PVC/PBA was lower than that of PVC/DOP and increased with increasing intrinsic viscosity of PBA. When the value of intrinsic viscosity was 0.115 dL/g, the elongation at break of PVC/PBA could reach 271.9 % and was higher than that of PVC/DOP. Besides, the liquid phase migration of PBA decreased with increasing intrinsic viscosity and the highest was 0.143 %. TGA showed that, PVC plasticized by PBA provided better thermal stability and flame retardancy than PVC/DOP.

Synthesis and Properties of Environmentally-friendly Flame Retardant

2015, 29 (11): 97-101 ; DOI: 10.19491/j.issn.1001-9278.2015.11.017

Abstract ( 665 )

N,N′-\[1,3-phenylenebis (methylene)\] bis-P,P,P′,P′-tetraphenyl ester (PNBE) was synthesized and characterized by elemental analysis (EA), mass spectra (MS), infrared spectroscopy (IR), and nuclear magnetic resonance (NMR). PNBE was introduced into epoxy resins as a flame retardant by solution casting. PNBE of 5 % could increase the limit oxygen index to 31.8 %, and the flame retardant grade was V-0 level. It worked in both condensed and gas phases but mainly followed the condensed phase mechanism.

Numerical Simulation of Melt Conveying Sections of a Special Single Screw Extruder for PLA

2015, 29 (11): 102-107 ; DOI: 10.19491/j.issn.1001-9278.2015.11.018

Abstract ( 624 )

The conveying section of three types of single screws of extruders for poly(lactic acid) was simulated by using Polyflow. The mixing performance of the three types of screws was analyzed by taking the flow path of the 24 mm reference line of the screw axis. Under the same process conditions, the axial melt velocity on the common type and pineapple-like screws was relatively large, a local recirculation region was formed which was not conducive to the transfer of the melt. The pineapple-like screw had high flow velocity and viscosity, so that the uniformity of the material was continuously improved in the flow field in order to obtain a higher shear rate, so the dispersion of the extrusion product was better. In extrusion process, the viscosity of the melt was consistent with the change of the flow velocity, and the shear action of the melt increased with increasing flow velocity, which led to the decrease of viscosity and the increase of the flow velocity.

Single Neuron Adaptive PID Control for Clamping Mechanism Injection Molding Machines

liang luo, li jiangyuan

2015, 29 (11): 108-112 ; DOI: 10.19491/j.issn.1001-9278.2015.11.019

Abstract ( 628 )

A single neuron adaptive PID controller was designed, using AMESim and Simulink for joint simulation, established the model of hydraulic servo system of injection molding machine clamping mechanism. The simulation results show that compared with the conventional PID controller, using single neuron adaptive PID controller, the system has better robustness and makes the system has good environmental adaptability.

Development of Injection Molds for Automobile Fuel Tank Sealing Covers

2015, 29 (11): 113-116 ; DOI: 10.19491/j.issn.1001-9278.2015.11.020

Abstract ( 480 )

The inject part of fuel tank sealing covers made from ether ester type thermoplastic elastomer (TEEE) had a torque structure and was difficult to be demolded. In order to achieve easy demolding, a reasonable spell structure was designed and multiple movement was adopted in the mold. Due to the large difference in wall thickness, more cooling waterway was designed in the template and core, which ensured the accuracy and production efficiency of the product.