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2015, Volume 29 Issue 10 Publication date: 26 October 2015 Previous Issue Next Issue

Progresses in Preparation and Processing Methods of Plastics Pipes for Medical Application and Their Mechanical Properties

2015, 29 (10): 1-6 ; DOI: 10.19491/j.issn.1001-9278.2015.10.001

Abstract ( 335 )

The preparation and processing methods of artificial blood vessels and balloon catheters were reviewed. The mechanical properties of plastic pipes (artificial blood vessels,intravascular polyurethane catheters) were summarized.The application of plastic microchannel products(MCF,MCT) in medical treatment was discussed and prospected.

Review on the High Barrier Polymer Films Enhanced by Nanoplatelets

2015, 29 (10): 7-13 ; DOI: 10.19491/j.issn.1001-9278.2015.10.002

Abstract ( 363 )

The preparation of polymer/nanoplatelet nanocomposites was reviewed. The mechanism for the improvement in the barrier performance of polymer nanocomposites was systematically elucidated by taking montmorillonite(MMT), layered double hydroxide (LDHs) and graphene (GNSs) as the typical examples. The main challenges in the preparation for polymer nanocomposites with high gas barrier property and multifunction were discussed.

Research Progress of Entry Converging Flow for Polymer Fluids

2015, 29 (10): 14-19 ; DOI: 10.19491/j.issn.1001-9278.2015.10.003

Abstract ( 346 )

In this paper, the research progress of the entry converging flow of polymer fluids was reviewed, including the theoretical analysis, computer simulation, obtainment of the extensional viscosity, and decrease of the entry converging flow. Moreover, the study about the entry converging flow of polymer fluids was forecasted.

Effects of Wood Flour Content and Ammonium Polyphosphate on the Flame Retardant and Mechanical Properties of High Density Polyethylene/Wood Flour Composites

2015, 29 (10): 20-24 ; DOI: 10.19491/j.issn.1001-9278.2015.10.004

Abstract ( 470 )

The effect of ammonium polyphosphate (APP) and wood flour (WF) content on the flame retardant and mechanical properties of high density polyethylene/wood flour composites (WPC) was investigated. The flammability and mechanical preperties of WPC were characterized by limiting oxygen index (LOI), UL94 vertical burning, cone calorimeter (CONE) tests, thermogravimetric analysis, Fourier transform infrared (FTIR) spectroscopy, and mechanical test. Loaded with 40 % WF, the LOI of the composites was increased to 30.5 % and UL 94 rating achieved V-0 level. CONE data revealed that heat release rate and total heatrelease were significantly decreased. The thermal stability of WPC was improved due to the protective char layer formed during certain chemical reaction occurring between WF and APP. The mechanical properties of WPC were also improved.

Synthesis of 3-Arylbenzofunanone Analogues

2015, 29 (10): 25-31 ; DOI: 10.19491/j.issn.1001-9278.2015.10.005

Abstract ( 372 )

Starting from 50ω% aqueous glyoxylic acid and 2,4-di-tert-butylphenol，synthesized 3-(3,4-dimethylphenyl)-5,7-di-tert-butyl-methyl-3H-benzofuran-2-one by" process esterification addition - alkylation- extractive crystallization", and studied the effects of process parameters on the yield of the target product comprehensively and systematically. The synthesis reaction conditions were optimized, the yield of target product reaches 70.2% when the molar ratio of glyoxylic acid and alkylphenol equales to 1.3:1, at 100℃, reaction 3h, in esterification addition reaction, and when the molar ratio of catalyst to alkylphenol is 0.12:1, at -0.06MPa, reaction 2.5h, in alkylation.

Preparation and Characterization of Carbon Fiber Composites Based on EP/BMI Resin Matrix

2015, 29 (10): 32-36 ; DOI: 10.19491/j.issn.1001-9278.2015.10.006

Abstract ( 512 )

Epoxy composites were prepared with E-51,BMI,DDS, and short carbon fiber (SCF) and the effect of the content of SCF on the mechanical and thermal properties of the composites was studied. It was found that when the carbon fiber content was 0.25 %, the mechanical properties of the composites were optimal and the tensile strength, flexural strength, flexural modulus, and notch impact toughness were increased by 48.52, 32.15, 25.77, and 150.91 % based on than that of EP/BMI/DDS composite without carbon fiber. In addition, carbon fiber improved the thermal properties of the composites.

Research on Poly(vinyl chloride) Modified with Poly(hydroxyalkanoates)

2015, 29 (10): 37-41 ; DOI: 10.19491/j.issn.1001-9278.2015.10.007

Abstract ( 541 )

Poly(vinyl chloride)/dioctyl phthalate/poly(hydroxyalkanoates)(PVC/DOP/PHA) blends were prepared by melt blending. The mechanical property, melt flow behavior, and morphology of the blends were studied. The tensile strength of the blends increased with increasing PHA content and decreasing DOP content, while the elongation at break was increased first and then decreased, giving a maximum value at a PHA content of 10.7 %. In PVC/PHA system, the mechanical properties, notably the toughness, and the melt flow index increased obviously at high PHA content.

Flame Retardant Effect of Polyaluminosiloxane on PC

2015, 29 (10): 42-46 ; DOI: 10.19491/j.issn.1001-9278.2015.10.008

Abstract ( 493 )

The polyaluminosiloxane was prepared through cohydrolysis condensation.The flame retardant mechanism of the polyaluminosiloxane for polycarbonate(PC) was studied by limited oxygen index, thermogravimetric analysis, scanning electron microscopy, and energy dispersive X-ray spectroscopy(EDX). It was found that the polyaluminosiloxane improved the limiting oxygen index of PC. In the thermal degradation process with 5 mass% loading of polyaluminosiloxane, the thermal degradation rate was reduced, and the char yield at 800 ℃ was increased by 44.1 %. During the combustion process, the polyaluminosiloxane would migrate to surface and interact with PC degradation product to promote the formation of carbon residue. The accumulation of Si and Al on the surface enhanced the carbon layer which retarded further pyrolysis of the material and hinder the transmission of heat and combustible gases, and thus improved the flame retardant effect.

Synthesis of Phosphazene Derivatives with Long Chain and Their Application in Polypropylene as a Flame-retardant

2015, 29 (10): 47-52 ; DOI: 10.19491/j.issn.1001-9278.2015.10.009

Abstract ( 488 )

Hex (dodecylamino) cyclotriphosphazene (HDCP) and Hex (Octylamino) cyclotriphosphazene (HOCP) were synthesized by nucleophilic substitution reaction, then the two were introduced into polypropylene (PP), in which ammonium polyphosphate (APP) and pentaerythritol (PER) were also present. The flame retardancy of systems was measured bylimiting oxygen index (LOI), UL94, and cone calorimetry(CCT).The mechanical properties of flameretarded PP were studied including elongation at break,tensile and impact strengths.It showed that the LOI of flameretarded PP increased about 13 % when 2 % phosphazene derivative were introduced. With increasing HDCP and HOCP，the impact strength of flameretarded PP was improved, however, the elongation at break was decreased.

Properties of PCT Cured Epoxy Foam

2015, 29 (10): 53-58 ; DOI: 10.19491/j.issn.1001-9278.2015.10.010

Abstract ( 426 )

A new epoxy foam was prepared from bisphenol A type epoxy resin(E-51)，PCT，npentane (N-PT), and tween-80/silicone oil, and cured at room temperature. The effect of amount of PCT on the foaming time and properties of the foam was studied. When the loading of PCT was 30 % (based on epoxy), the foaming time was 5 min. The optimal formula of the new epoxy foamwas as follows (in parts): E-51100,PCT30, N-PT5, (tween-80/silicone oil)5. The optimum process was，PCT and tween-80/silicone oil were first mixed and stirred，then N-PT was added，stirred，poured，foamed and molded. Some properties of the foam were: density 0.0467 g/cm^3，bibulous rate 2.9 %，thermal conductivity 0.037 W/(m·K)，compressive strength 276 kPa，and initial weightloss temperature and the temperature at fastest weightloss rate were 248.4 ℃and 362.3 ℃，respectively.

Theoretical Research and Numerical Simulation of Bubble Breakup in Polymer Foaming Process

2015, 29 (10): 59-63 ; DOI: 10.19491/j.issn.1001-9278.2015.10.011

Abstract ( 450 )

The bubble breakup in polymer foaming process was studied by theoretical calculation and numerical simulation in this paper. For a given bubble in simple shear flow, the breakup time was calculated by a theoretical derivation method and was simulatedby a volumeoffluid method. The breakup times derived from the two ways were compared.The factors which influenced the bubble breakup time were analyzed, and it was found that the bubble breakup time was proportional to interfacial energy, and inversely proportional tointerfacial viscosity, bubble diameter, and the square of shearing rate.

Research of Injection Molding Process for Carbon Fiber/Glass Fiber Reinforced Composite

2015, 29 (10): 64-67 ; DOI: 10.19491/j.issn.1001-9278.2015.10.012

Abstract ( 481 )

By numerical simulation and single factor experiments, the injection warpage of composites reinforced with 30 % carbon fiber or 30 % glass fiber was studied. The influence of various parameters such as melt temperature, injection time, holding time, packing pressure on the warpage was also investigated through multivariate experiments.The results showed: the warpage based on 30 % carbon fiber was lower than that based on 30 % glass fiber, with the maximum warpage being 4.107 and 5.090 mm, respectively. The most effective processing parameter for carbon and glass fiber reinforced composites was packing pressure and holding time, respectively.

Numerical Simulation of Rheological Behavior of Polyethylene Melts Through a Square Cylinder

2015, 29 (10): 68-72 ; DOI: 10.19491/j.issn.1001-9278.2015.10.013

Abstract ( 394 )

The constitutive behavior of lowdensity polyethylene (PE-LD)were described by the DCPP and S-MDCPP models in this study. The modified finite increment calculus (FIC) procedure was introduced into the iterative fractional step algorithm, and the discrete elastic viscous stress split (DEVSS) and streamlineupwind (SU) techniques were employed to cope with the convectiondominated problem of the viscoelastic flow analysis in order to enhance the computational stability. It showed that the velocity, isochromatic fringe pattern of principle stress difference and backbone stretch distributions predicted by the DCPP and S-MDCPP models agreed very well.Moreover, the predicted velocity, pressure and backbone stretch distributions using the S-MDCPP model at different Weissenberg numbers (Wi) were discussed and it exhibited the velocity and pressure were enlarged with the increase of Wi.

Optimization of Injection Molding Process Parameters Based on Moldflow and Orthogonal Experimental Design

2015, 29 (10): 73-77 ; DOI: 10.19491/j.issn.1001-9278.2015.10.014

Abstract ( 582 )

Taking protective covers as an example, Moldflow software was applied to simulate the injection molding process. Orthogonal experiments were conducted to study the influence of five process parameters on volume shrinkage and warpage: melt temperature, mold surface temperature, injection time, holding pressure time, and holding pressure. By analyzing the signaltonoise ratio and variance of the results, the best level of each factor was obtained, and then the optimal combination of process parameters was acquired.

Preparation and Application of Pentaerythritol Zinc Heat Stabilizer

2015, 29 (10): 78-82 ; DOI: 10.19491/j.issn.1001-9278.2015.10.015

Abstract ( 446 )

Pentaerythritol zinc was prepared from active zinc oxide and pentaerythritol. The influence of mole ratio of zinc oxide and pentaerythritol，reaction temperature and time on the performance of the product was discussed．The optimum reaction conditions were as follows：mole ratio of active zinc oxide over pentaerythritol 3：2，reaction temperature 220 ℃，and reaction time 2 h．When pentaerythritol zinc was used in PVC, the staticthermal stability time could reach 49.4 min, which was nearly 7 times without pentaerythritol zinc. The longest dynamicthermal stability time was 132 s, the shortest plasticizing time was 83 s, and the minimum torque was 28 N·m. These behavior showed that pentaerythritol zinc constituted a good thermal stabilizer for PVC.

Synthesis of a Surface Modifier Containing Isocyanate on Poly(vinyl chloride)/Wood Powder Composites

2015, 29 (10): 83-87 ; DOI: 10.19491/j.issn.1001-9278.2015.10.016

Abstract ( 439 )

In this study, a kind of surface modifiers was synthesized from isocyanate and aliphatic alcohol and was used in poly(vinyl chloride) based woodplastic composites(WPC). After treated with 3 % surface modifier, the surface water contact angle of wood flour increased to 146.0°, and the tensile strength of WPC increased by almost 32.6 % and the elongation at break increased by more than 42.1 %. The plasticizing time of WPC decreased from 57.5 s to 46.7 s, the equilibrium torque decreased from 24.7 to 18.2 N·m, and the plasticizing temperature decreased from 147.3 to 140.4 ℃. In addition, the longer the carbon chain length of aliphatic alcohol, the better the surface modification effect of the surface modifier.

Channelgroove Coupling Melting Model for Single Screw Extruders with a Grooved Melting Zone

2015, 29 (10): 88-93 ; DOI: 10.19491/j.issn.1001-9278.2015.10.017

Abstract ( 351 )

Experiments were made on a platform with hydraulicclamshell type barrels to study the relationship between the melting length and screw rotate speed. Channelgroove coupling melting model for single screw extruders with grooved barrel was confirmed.Compared with conventional and IKV single screw extruders, it was found that the melting lengths in the single screw extruder with a grooved melting zone were shorter and more stable and melting efficiency could be improved greatly.

Injection Mould Design for Mounting Plates of High Frequency Electric Couplers

2015, 29 (10): 94-97 ; DOI: 10.19491/j.issn.1001-9278.2015.10.018

Abstract ( 391 )

The forming process of mounting plates of high frequency electric couplers was analyzed and the structure of injection mold was decided. The selection of parting surfaces was introduced.The sideparting corepulling mechanism and ejecting mechanism were designed. Based on structural features of plastic parts, three partings and two detrusions were adopted, which led to smooth demolding and high accuracy. Practice had proven that the mold structure was reasonable and production efficiency was high.

Influence of Screw Configuration on Polyethylene/Polyamide 6 In-situ Blends Prepared by Reactive Extrusion

2015, 29 (10): 98-102 ; DOI: 10.19491/j.issn.1001-9278.2015.10.019

Abstract ( 320 )

High-density polyethylene/polyamide 6 (PE-HD/PA6) insitu blends were prepared by reactive extrusion from ε-caprolactam (CL) and highdensity polyethylene (PE-HD) in presence of PE-HD grafted maleic anhydride (PE-HD-g-MAH).The influence of screw configuration on the preparation of PE-HD/PA 6 in-situ blends was explored. It was found that the longer the residence time for the screw configuration, the higher the CL monomer conversion of the blend. Among the three configurations, the largepitch screw element provided the smallest diameter of PA6 particles in the blend, since such a configuration was beneficial to the rupture and dispersion of CL in the matrix.