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2013, Volume 27 Issue 09 Publication date: 26 September 2013 Previous Issue Next Issue

Research Progress on Shear Thickening Fluids and Its Application in Body Protection

2013, 27 (09): 1-5 ; DOI: 10.19491/j.issn.1001-9278.2013.09.001

Abstract ( 1180 )

This paper summarizes the research about shear thickening fluids at home and abroad, and gives a review from perspective of its rheological properties, the mechanism of shear thickening and its application to body protective equipments. Compared with the traditional soft body armors, shear thickening fluids not only have better protective performance, but also offer protective parts more effective protection for its lightweight, comfortable, flexible features. It enjoys wide application prospects in civil and military areas.

Research Progress in Modification of Polyhydroxyalkanoate and Its Foam Materials

2013, 27 (09): 6-10 ; DOI: 10.19491/j.issn.1001-9278.2013.09.002

Abstract ( 1122 )

The modification methods and foaming process of polyhydroxyalkanoate (PHA) in recent years were reviewed worldwide. The modification methods include physical modification, chemical modification and biological modification. And the foaming process mostly involves molded-press method, injection method, extrusion method etc.

Research Progress in Flame Retarded Thermoplastis Ploymer/Wood Fiber Composites

Qin LU

2013, 27 (09): 11-16 ; DOI: 10.19491/j.issn.1001-9278.2013.09.003

Abstract ( 1156 )

The recent research progress in the thermoplastic polymer/wood fiber composite was reviewed. Firstly, flame retardant mechanism of such composites was analyzed, subsequently the effects of non-halogen flame retardants such as inorganic, intumescent, nanoparticles, and composite systems on the flame retardancy and mechanical properties of the composites were summarized. At last, the developing trend of flame retardant thermoplastic polymer/wood fiber composite was pointed out.

Combustion Characteristics of Phenolic Foam Reinforced by Nature Bamboo Fiber

ZHUANG Xiao-Wei Yu-zhi Xu Wei ZHANG Chun-peng WANG Fu-xiang CHU

2013, 27 (09): 17-21 ; DOI: 10.19491/j.issn.1001-9278.2013.09.004

Abstract ( 853 )

Combustion characteristics of phenolic foam which contained various amount of nature bamboo fiber was tested using cone calorimeter. It was found that the time of ignition of phenolic foam was decreased with increasing content of nature bamboo fiber; while heat release rate, total heat release, mass loss rate, smoke product rate, and total smoke product were increased. Because heat transfer was blocked in the inner layer, the total heat release was slow down phenolic and the total smoke product in the phase of 0~480 s combustion was reduced. When the addition of nature bamboo fiber was 1.5~3.5 %, the requirement for flame-retardancy could generally satisfied. However, when the addition was more than 5 %, the phenolic foam must be further modified to be flame-retardant.

Ultimate Impact Toughness and Deformation Mechanism for ABS Resin

2013, 27 (09): 22-27 ; DOI: 10.19491/j.issn.1001-9278.2013.09.005

Abstract ( 885 )

A series of acrylonitrile-butadiene-styrene copolymers (ABS) were prepared by melt blending PB-g-SAN with styrene-co-acrylonitrile (SAN). The effect of rubber content on the impact and tensile properties of ABS was investigated. The dispersion morphology and deformation mechanism were studied by transmission electron microscope (TEM). It was found that the impact strength increased firstly and then decreased with increasing rubber content. The elongation at break increased with the increasing rubber content. A uniform dispersion of rubbery particle in the matrix could be observed when the rubber content was lower. However, at higher rubber contents, the dispersion morphology became poorer and the agglomeration of rubber particles occurred. The main deformation mechanism of the ABS resin was changed from cavitations to the craze and then shears yielding, with increasing rubber content.

Shape Memory Effects of Chemically Crosslinked PE-LD/SBS Blends

2013, 27 (09): 28-31 ; DOI: 10.19491/j.issn.1001-9278.2013.09.007

Abstract ( 942 )

A series of novel shape memory blend materials were fabricated by blending three kinds of styrene butadiene copolymer (SBS) with low density polyethylene (LDPE) and were chemically crosslinked by dicumyl peroxide (DCP). The degree of crosslinking, and the tensile strength and the elongation at break of the crosslinked blends were tested, at last, the shape memory effect of the blends were investigated. The results show that when the content of DCP were increased, the blend of the degree of crosslinking increased, wherein the degree of crosslinking of the SBS1201/LDPE blend was maximum. And with the increase in the degree of crosslinking, the tensile strength and break elongation were decreased. Moreover, when the DCP content was 0.5 to 1.5%, the crosslinked blend has the good shape memory behavior.

Study on Synthesis and Preparation of Polyurethane Film Modified by PVB

2013, 27 (09): 32-36 ; DOI: 10.19491/j.issn.1001-9278.2013.09.008

Abstract ( 1023 )

A new polyurethane membrane was prepared by a chain extending reaction of PVB and end-closed polyurethane prepolymer. The structure and performance of this membrane were investigated by FTIR, TG, DMA, and mechanical test. The new polyurethane membrane gave rise to good thermal stability. The content of TDI in the membrane was low and thus had a lower toxicity. Binding strength with polyamide fiber was increased to 58.58 N/2. 5 cm.

Structure and Properties of In-situ Microfibrillar Reinforced Composites

2013, 27 (09): 37-40 ; DOI: 10.19491/j.issn.1001-9278.2013.09.009

Abstract ( 772 )

HDPE/PA6 in-situ microfibrillar reinforced composites were prepared by melt extrusion— hot tensile — pull stretch. The effect of contents of dispersed phase PA6 in matrix on morphology and distribution was analyzed by SEM. Discussed the effect of adding quantity of PA6 in composites under two different processing on tensile properties, impact strength and the influence of processing method on the mechanical behavior of composites. The result indicates that there were fibers with diameter of 2~5 in in-situ microfibrillar reinforced composites, where HDPE/PA6 was 85/15, the diameter of fiber is about 3 . At this time, compared with common blends, the tensile strength of in-situ microfibrillar reinforced composites improved 6.9%, the tensile modulus improved 14.8%, impact strength improved 10.03%.

The Air Aging Properties and Storage Life Prediction of Epoxy Foam

2013, 27 (09): 41-45 ; DOI: 10.19491/j.issn.1001-9278.2013.09.010

Abstract ( 745 )

In this paper, by means of the impact strength of sample which passes through air aging test, the storage life of two kinds of epoxy foam at 23℃ was predicted. The experimental results showed that the storage life of both kinds of epoxy foam at 23 ℃ would be 28 years. The high-temperature resistance aging performance of the homemade epoxy foam was better.

Tertiary amine-catalyzed waterborne alkyd resin/epoxy resin curing behavior and its material properties

GAO Jun-Gang

2013, 27 (09): 46-51 ; DOI: 10.19491/j.issn.1001-9278.2013.09.011

Abstract ( 1098 )

A waterborne epoxy/alkyd resin (EP/AR) was synthesized, which was simply used as a coating or reinforced with glass fiber and cured forming composites. Studies using infrared spectrometer (FTIR) and differential scanning calorimeter (DSC) found that tertiary amine had a good catalyzing effect for the curing. The glass transition temperature (Tg) and thermal degradation of the composites were characterized by dynamic mechanical spectrometer (DMA) and thermal analysis (TG). The mechanical and electrical properties of the composites and coating were determined. When the mass ratio of AR with ER was 1 :1, the Tg was 64.6 oC, the tensile and impact strengths were 141.67 MPa and 120.54 kJ/m2, respectively. The dielectric constant and dielectric loss tangent of the composites were between 1.5 1.99 and between 0.001~0.008, respectively. The pencil rigidity of the coating was over 4H and impact strength reached 20 kg·cm.

Investigation on Curing Kinetics and Mechanical Properties of Bismaleimide/Benzoxazine/Graphene Copolymer

Guanglei WU

2013, 27 (09): 52-56 ; DOI: 10.19491/j.issn.1001-9278.2013.09.012

Abstract ( 900 )

The non-isothermal curing kinetics of bismaleimide/benzoxazine/grapheme (BMI/BOZ/GNS) systems was studied by using differential scanning calorimetry (DSC). The curing kinetics parameters were obtained using Kissinger and Ozawa equations. The effect of GNS on the mechanical performances of BMI/BOZ/GNS system was investigated. The tensile properties of BMI/BOZ/GNS system increased firstly and then decreased with increasing GNS content. When the content of GNS was 0.15 wt %, the mechanical properties of BMI/BOZ/GNS system were the best.

Preparation and Characterization of Soluble Polyimide Based on a Novel Pyridine-containing Aromatic Diamine

2013, 27 (09): 57-62 ; DOI: 10.19491/j.issn.1001-9278.2013.09.013

Abstract ( 852 )

A novel pyridine-containing aromatic diamine monomer,4-phenyl-2,6-bis[4-(4-aminoph enoxy) phenyl]pyridine (ρ-PAPP) was successfully synthesized via nucleophilic substitution reaction, modified Chichibabin reaction, and catalytic reduction with hydrazine monohydrate,4-hydroxyacetophenone and benzaldehyde. Based on this, a pyridine-containing polyimide was synthesized via conventional two-step method by using ρ-PAPP as a diamine monomer, 2,2-bis[4-(3,4dicarboxyphenoxy)phenyl] propane dianhydride as a dianhydride monomer in N,N-dimethylformamide(DMF).The structure and properties of the polymer were characterized by FTIR, DSC, TGA, XRD, solubility testing. There were characteristic peaks of polyimide around 1780、1723、1378 cm-1 in the FTIR spectrum. The polyimide was soluble in common organic solvents. The polyimide had good thermal stability with glass transition temperature(Tg) of 191.2 °C, the temperature at 10 % weight loss was 473.8 °C in nitrogen atmosphere and the residual mass at 800 °C was 43 %. The other properties included tensile strengths of 98.5 MPa, tensile modulus of 1.24 GPa, and water uptake of 0.67 %.

Experimental Research of Effects of the Kinetic Friction Coefficient for Polymer Powders

HU Xue-Yong

2013, 27 (09): 63-68 ; DOI: 10.19491/j.issn.1001-9278.2013.09.014

Abstract ( 892 )

A procedure for automatic acquisition of experimental data was designed. On-line data-acquisition (DAQ) system and calculation of the kinetic friction coefficient based on Maths function of the LabVIEW were obtained for pressure, torque, and temperature. Variation of the kinetic friction coefficient at different pressure, temperature, rotate speed and the material fineness was compared and analyzed. The experimental result showed that the kinetic friction coefficient decreased with increasing pressure. Properties of different powder had a great effect on the kinetic friction coefficient. The kinetic friction coefficient of the PTFE was the minimum, and the kinetic friction coefficient of rubber powders increased with increasing particle size.

Research on FTIR Characteristic Indexes of Polycarbonate During Outdoor Exposure

ZHANG Xiao-dong

2013, 27 (09): 69-72 ; DOI: 10.19491/j.issn.1001-9278.2013.09.015

Abstract ( 1162 )

In this article, the color differential and tensile strength of polycarbonate(PC) after different weathering stage during one year in Qionghai, Ruoqiang and Hailaer were tested, and the FTIR characteristic indexes were also calculated. On this basis，the mechanisms of PC weathering in different location and Pearson correlation coefficients between PC properties and IR feature indexes have been studied. The results show that when exposed in Qionghai, the PC will conduct both Fries-rearrangement and photo-oxidation reaction, it may mainly conduct photo-oxidation reaction in Ruoqiang and Hailaer. All these two reactions will cause color change in the, other hand, only Fries-rearrangement reaction cause tensile strength descend.

Determination of Acrylonitrile Content in SAN by FTIR

LIN Hong-Xiong Dalei YUE

2013, 27 (09): 73-75 ; DOI: 10.19491/j.issn.1001-9278.2013.09.016

Abstract ( 1016 )

In the paper, the content of acrylonitrile in SAN was determined by Fourier transform infrared spectrometry (FTIR). By means of the acrylonitrile's characteristic peak at 2237 cm-1 and styrene's characteristic peak at 700 cm-1, the calibrated curve for determining the acrylonitrile content in SAN by FTIR spectrometry was established and its veracity and precision were evaluated. Results showed that its maximum relative error was 2.8 % , the relative standard deviation was 2.48 % when determining the same sample. The method had good veracity and precision.

Rheological Behavior and Barrier Resistance of Poly(propylene carbonate)/Ethylene-Vinyl Alcohol/Clay Nanocomposites

2013, 27 (09): 76-80 ; DOI: 10.19491/j.issn.1001-9278.2013.09.017

Abstract ( 831 )

Poly(propylene carbonate)/clay and PPC/ Ethylene-vinyl alcohol (EVOH) /clay nanocom- posites were prepared by melt blending. Rheological behavior, morphology and barrier resistance of PPC nanocomposites were investigated. Results illuminated that composites prepared by higher molecular weight of PPC resin, its complex viscosity, storage modulus and elastic modulus show higher values. With the addition of clay and PE-g-MAH, complex viscosity and modulus of PPC/EVOH composites were increased. The interfacial action among PPC, EVOH and clay was enhanced with the addition PE-g-MAH. By the introduction of clay and PE-g-MAH, both the compatibility and barrier resistance of PPC and EVOH composites increased significantly.

Study on the Properties of Flame Retarded Epoxy Resin with Reactive or Additive Flame Retardant Containing-phosphorus

CAO Jun YI Huijun HONG Zhen LIANG Bing

2013, 27 (09): 81-84 ; DOI: 10.19491/j.issn.1001-9278.2013.09.019

Abstract ( 1013 )

The effect on mechanical properties and flame retardancy of flame retarded epoxy resin samples with different contents of reactive flame retardants and additive flame retardants were studied in this article, the thermal stability of different flame retarded epoxy resin were also studied. The results showed that the mechanical properties and flame retardancy of DOPO was better than DOPO-CH2OH in the reactive flame retardants, the properties of MP was better than APP in the additive flame retardants. Comparing the two types of flame retardants, the mechanical properties, flame retardancy and thermal stability of the two reactive flame retardant was better than additive flame retardant of MP and APP.

Development of Pressure in Conical Single Screw Extruders

WANG Ke-jian

2013, 27 (09): 85-88 ; DOI: 10.19491/j.issn.1001-9278.2013.09.020

Abstract ( 1003 )

Based on force solid plug-force equilibrium analyses, pressure and advancing angle as well as power models were developed for double-conical screws either with a gradually shallower channel or a constant channel. Numerical calculation showed that the conical screw channel may develop higher pressure than cylindrical screw channel, and this trend became stronger with larger conical angle. The effect of conical angle on the pressure differed at different axial position. The conical screw possessed a larger advancing angle than the regular ones, thus resulted in a higher output and a reduced transporting power.

Study on Injection Mold for Automobile Interior Decoration Lock Body Based on Moldflow

ZHAO Long-Zhi

2013, 27 (09): 89-93 ; DOI: 10.19491/j.issn.1001-9278.2013.09.021

Abstract ( 953 )

The injection molding process of the automobile interior decoration lock body part was simulated based on Moldflow software in this paper. The best gate location, flowing, warping, and cooling during the injection were analyzed. According to the distribution of air traps in the part and the mold structure, the gating system was designed reasonably. Keeping constant time of holding pressure, the total deformation of the part reached a minimum value. When the local mass of the part and the thin wall surface was large, the warp deformation was seriously affected by the structure of the part.

Warpage Analysis of Plastic Injection Mold and Moldbase Optimization on EMX

Ma Song-Bai

2013, 27 (09): 94-97 ; DOI: 10.19491/j.issn.1001-9278.2013.09.022

Abstract ( 853 )

Taking the mold design scheme of a plastic rear cover (modeling in ProE\EMX6.0) as an example, based on Autodesk Moldflow Insight (AMI) 2010, the product warpage and its reason was analyzed. According to simulation results, the gating system, cooling system of the original mold design schemes were modified, the holding pressure curve of injection molding machine was optimized, so that the product warpage was reduced to a acceptable range.