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2010, Volume 24 Issue 02 Publication date: 26 February 2010 Previous Issue Next Issue

Polyhydroxyalkanoates - A Broad Applied Biodegradable Polymer

Jiang Ying

2010, 24 (02): 1-5 ; DOI: 10.19491/j.issn.1001-9278.2010.02.001

Abstract ( 2811 )

The applications of polyhydroxyalkanoates (PHAs) in different fields including package, wastewater treating, medical devices, controlled releasing, agricultural film, and nitrogen fixation were reviewed in this article. In addition, composites of PHAs with carbon nano-tubes and montmorillonite for special applications were also introduced.

Research Progress in High Dielectric Permittivity Polymeric Composites

2010, 24 (02): 6-10 ; DOI: 10.19491/j.issn.1001-9278.2010.02.002

Abstract ( 2364 )

The definition, characteristics, and polarization mechanism of dielectrics were first briefly introduced. The research and development of ferroelectric ceramics, metal and carbon filled polymers were reviewed.For the high dielectric permittivity polymeric composites used in embedded passive components and printed circuit boards, it was aimed to increase the dielectric permittivity and temperature resistance,decrease the dielectric loss,and stabilize dielectric permittivity and loss at wider ranges of temperature and frequency.

Technology Progress in Coextrusion Die of Plastic Film

Yuxia Zhang

2010, 24 (02): 11-20 ; DOI: 10.19491/j.issn.1001-9278.2010.02.003

Abstract ( 2551 )

Typical structure and features of coextrusion dies for multi-layer plastics films were introduced, including dies for casting multi-layer films （flat film method） and dies for blown multi-layer films （tubular film method）.Mayor dies for casting multi-layer films include manifold dies, feeding block dies and feed-block-manifold integrated dies. Dies for blown films involves cylindrical mandrel dies and cylindrical stack dies. Development situation of them in recent 10 years were also described in detail, covering innovative structure, enhanced adaptability and increasing layers of the films.

Study on the Hyperdispersion Property of Carbon Black in PA6

2010, 24 (02): 21-25 ; DOI: 10.19491/j.issn.1001-9278.2010.02.004

Abstract ( 2074 )

The PA6/CB masterbatch was prepared in the torque rheometer after CB was treated with different hyperdispersants in different organic solvents, which was used to prepare the PA6/CB composites. The dispersion of CB in the masterbatch, the processability of the masterbatch, and mechanical properties of PA6/CB composites were investigated. When CB was treated with polyurethane and dispersed in DMF, it was finely dispersed in PA with an average size of 50~70 nm. When the contents of masterbatch was 5 wt%, the tensile strength of PA6/CB composite was 105 MPa, 39 % higher than that of neat PA6.

Study on the Isothermal Crystallization Behavior of PP

Wen Bian-Ying

2010, 24 (02): 26-29 ; DOI: 10.19491/j.issn.1001-9278.2010.02.005

Abstract ( 2098 )

PP/talc and PP/CaCO3 composites were prepared via melt mixing method using Haake rheometer. The isothermal crystallization behavior of PP and the composites were investigated using differential scanning calorimetry(DSC). The effects of talc and calcium carbonate on the isothermal crystallization behavior of PP were compared. It showed that all the Avrami indexes of PP, neat or in the composites, were lower than 2.3, which showed that both homogeneous and heterogeneous nucleation mechanisms occurred in these systems. The crystallization rate decreased with increasing crystallization temperature. It was found that the effect of talc promoted the heterogeneous nucleation significantly, whereas the effect of CaCO3 was moderate.

Preparation and Luminescence Property of Polystyrene/CdTe Composites Emitting Green Light Under Visible Light

wang wen meijuan lin limei huang mianmian su

2010, 24 (02): 30-34 ; DOI: 10.19491/j.issn.1001-9278.2010.02.006

Abstract ( 2032 )

The dodecyl vinylbenzyldimethylammonium chloride was synthesized, which was subsequently encapsulated with CdTe quantum dot via electrostatic reaction and bulk free radically copolymerized with styrene. The structure and optical properties of the obtained copolymer polystyrene/CdTe was investigated using fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), scan electron microscopy (SEM), UV-visible absorption spectrum, and fluorescence spectrum. The polystyrene/CdTe composites emitted green light under ultraviolet and visible region (380~480 nm). When the content of CdTe quantum dot bearing monomer was 1.2 wt %, the luminescence quantum yield of polystyrene/CdTe was 9.6 %.

Effects of Epoxy Resin on Properties of Polyamide 6/EPDM-MA Composites

Jiang Yao-Gui Qi YANG Ya-Jiang HUANG Jing SUN Xiao-Lian CHENG

2010, 24 (02): 35-41 ; DOI: 10.19491/j.issn.1001-9278.2010.02.007

Abstract ( 2430 )

In order to improve the tensile strength of Polyamide 6 (PA6)/EPDM-MA blend, the PA6/EPDM-MA/Epoxy (EP) ternary composites were prepared. Two different types of epoxy resin with various epoxy equivalent were used. The effects of different epoxy on the mechanical properties, rheological behavior, crystallization behavior of the ternary composites were studied by mechanical testing, dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC). It was found that the tensile strength and Notched izod impact strength of PA6/EPDM-MA blend was enhanced with the content of EP. The result from DMA showed that storage modulus(G’) and complex viscosity (η*) increased with content of EP while dynamic loss tangent (tanδ) decreased. Moreover, the crystallinity first increased and then decreased when the EP content increasing. All above properties of the composites were more sensitive to the epoxy resin with low epoxy equivalent.

Study on the Properties of the Epoxy Resin/Novolac System Modified by Phosphorus containing Organosiloxane

LIU Wei-Qu

2010, 24 (02): 42-46 ; DOI: 10.19491/j.issn.1001-9278.2010.02.008

Abstract ( 2233 )

A phosphorus containing organosiloxane (GPTMS-DEP) was prepared using silane coupling agent and DEP, which was used as a modifier in epoxy systems. The flame retardancy of the modified epoxy resin reached 30 %. The glass transition temperatures (Tg) was 157 ℃, 45 ℃ higher than that of the neat system. The residual char yield under 720℃ and the temperature of 50 % weight loss increased obviously. SEM showed that GPTMS-DEP and epoxy resin was compatible when the content of GPTMS-DEP was below 20 %.

Preparation and Properties of PA6/Epoxy Resin Modified Montmorillonite Nanocomposites

2010, 24 (02): 47-51 ; DOI: 10.19491/j.issn.1001-9278.2010.02.009

Abstract ( 2001 )

Montmorillonite (MMT) was modified by epoxy resin leading to organic montmorillonite (OMMT), whose interlayer spacing increased from 1.22 nm to 5.13 nm. The OMMT was dispersed into PA6 as nano-scale particles forming nanocomposites. X-ray diffraction (XRD), transmission electron microscopy (TEM), universal testing machine, and thermogravimetric analysis (TGA) were used to investigate the morphology, mechanical properties, and thermal stability of PA6/OMMT nanocomposites. With increasing OMMT content, the strength, modulus, and heat distortion temperature of the PA6/OMMT nanocomposites increased. A tensile strength of 76 MPa，a bending modulus of 3.462 GPa， and a heat distortion temperature of 134 ℃ were obtained. The thermal stability of PA6 was also improved by OMMT, the temperature of 10 % weight loss reached 422 ℃, 16 ℃ higher than that of neat PA6.

Preparation and Properties of Long Glass Fiber Reinforced (Polypropylene/m-Polyamide 6)

2010, 24 (02): 52-56 ; DOI: 10.19491/j.issn.1001-9278.2010.02.010

Abstract ( 2190 )

Long glass fiber reinforced (polypropylene/m-polyamide 6) (LFT-PP/m-PA6) particles were prepared via melt pultrusion and cutting, and the interface interaction, mechanical properties and rheological behavior of the composites were investigated. The introduction of PA6 enhanced the interaction between LFT and PP, at the same time improved the mechanical and rheological properties of LFT/PP composites. At 30 C, the notch impact strengths of the composites based on homopolymerized PP（F401）and copolymerized（K712）were increased by 7.53 and 3.91 %, respectively.

Preparation and Property of Poly(vinyl acetate)-Organophilic Montmorillonite Nanocomposites Initiated by Emulsion Polymerization

LI Ling Xing-rong ZENG Xue-jun LAI

2010, 24 (02): 57-60 ; DOI: 10.19491/j.issn.1001-9278.2010.02.011

Abstract ( 2073 )

Nanocomposites of poly(vinyl acetate)/organophilic montmorillonite (PVAc/OMMT) were prepared via emulsion polymerization. The structure and morphology of the nanocomposites were characterized using X-ray diffraction(XRD)，transmission electron microscopy (TEM), and FT-IR spectrum. The thermal stability of the nanocomposites was investigated using thermogravimetric analysis and DSC. Intercalated structures were found in the nanocomposites. Based on neat PVAc, the glass transition temperature (Tg) of the nanocomposite was increased, the thermal stability and mechanical properties were also enhanced. The initial decomposition temperature of the nanocomposites increased with increasing contents of OMMT. The tensile strength of the nanocomposites were first increased and then decreased with increasing contents of OMMT. When the content of OMMT was 10 wt %, the maximum value of 7.87 MPa was obtained.

Effect of Antioxidant on the Structure and Properties of Photo-degradation Polyethylene Films

2010, 24 (02): 61-65 ; DOI: 10.19491/j.issn.1001-9278.2010.02.012

Abstract ( 1582 )

The effect of antioxidant 1010 on photo-degradation PE film was studied via UV irradiation. The structure and properties of PE film before and after UV aging were characterized using FT-IR, UV spectrum, and mechanical testing. Results indicated that antioxidant 1010 could inhibit the photo-degradation and reduce the amount and types of carbonyl entities during the UV irradiation on PE film. The reserved elongation at break of photo-degradation PE films were less than 80 % after 3 d UV-irradiation, while the reserved elongation at break of PE photo-degradation film containing 0.3 wt % antioxidant were less than 80 % after 4~5 d UV-irradiation，which showed that the induce period of PE films containing antioxidant had been prolonged.

Effect of Injection Molding Parameters on the Foaming Behavior and Mechanical Properties of PP/ SiO₂ Nanocomposites

2010, 24 (02): 66-72 ; DOI: 10.19491/j.issn.1001-9278.2010.02.013

Abstract ( 2193 )

The effect of nozzle temperature, pressure, melt viscosity, and cooling time on the cell size, cell density, and mechanical properties of chemically foamed PP/SiO2 nanocomposites were studied through orthogonal experiments. The Image-Pro software was used to count the cell size. It was found that the nozzle temperature was the most important factor, melt viscosity was the second. The optimal injection processing parameters were nozzle temperature 175 ℃, injection pressure 67.5 MPa, melt viscosity 95 %, and cooling time 35 s, by which an impact strength of 5.45 kJ/m2 ,an average cell diameter of 15.71 m , an cell density was 9.8×106 bubble/cm3 were obtained.

Effect of Blowing Processing Parameters on the Property of PP Foamed Board

liu hui

2010, 24 (02): 73-77 ; DOI: 10.19491/j.issn.1001-9278.2010.02.014

Abstract ( 1546 )

PP was cross-linked with silane via twin-screw extrusion. Using AC as a blowing agent, foamed PP board was prepared by compression molding in which the bubble was well distributed and the hole was very meticulous. The effect of the processing parameters on the impact and bending strengths, and the density of board were investigated. PP board with the optimal performance was obtained when the content of foaming agent was 2.5 phr, the foam control agent was 8 phr, the molding temperature was 195 ℃, the pressure was 20 MPa, and the compression time was 17 min.

Numerical Simulation of the Extrudate Swell of Polymer Melt Through Rectangular Die

Li Yong

2010, 24 (02): 78-82 ; DOI: 10.19491/j.issn.1001-9278.2010.02.016

Abstract ( 2103 )

In this paper, the finite element method of Picard iterative format was applied for analyzing three-dimensional extrudate swell of viscoelastic fluid flows using Wager integral constitutive equations. During each iteration, the updated streamline of boundaries was generated according to boundary condition of velocity. The streamline of Gauss point was acquired according to the velocity field of previous iteration. The stress was treated as pseudo-body and the format of iteration was given. Extrudate swell of different width and length of the rectangular die were analyzed. Results of swell ratios influenced by width and length of die were shown. It showed that the swell ratio increased with increasing ratio of width to thickness, and decreased with increasing length of runner. The results were very accurate and were compared with two dimension solutions and experiment. It proved that this method was efficient and reliable.

Study on the Effect of Inorganic nano-particle on Anti-migration of Plasticizer in Printed PVC Films

YANG Bao-Hong

2010, 24 (02): 83-86 ; DOI: 10.19491/j.issn.1001-9278.2010.02.018

Abstract ( 2316 )

The influence of nano-CaCO3 and nano-SiO2 on the printing performance of PVC film were studied. It was found that nano-CaCO3 and nano-SiO2 could reduce the migration of plasticizers from the PVC film, the higher of the content of nano-particles, the more effective of the anti-migration and the printing ink absorption ability of the film was improved. The content of the nano-particle should be below 20 phr, otherwise the mechanical properties and printing performance of PVC film would decreased. The agglomeration of the nano-particles was harmful for the printing property of PVC film.

Preparation of Aluminum Zinc Encapsulated Magnesium Hydroxide and Its Smoke Suppression Property in Plasticized Poly(vinyl chloride)

DONNG Liang-Liang

2010, 24 (02): 87-91 ; DOI: 10.19491/j.issn.1001-9278.2010.02.019

Abstract ( 2081 )

In an aqueous suspension of magnesium hydroxide, zinc aluminate was formed by the reaction between zinc sulfate and sodium and coated on the surface of magnesium hydroxide. The zinc aluminate coated magnesium hydroxide was added into PVC as a smoke suppression agent. The alkaline of the coated magnesium hydroxide was weaker and the oil absorption value was lower than plain magnesium hydroxide. When 20 phr zinc aluminate coated magnesium hydroxide was used, the total smoke release amount of PVC was 10.36 m2/m2, which was 24 % and 48 % lower than the systems containing 2 phr of zinc aluminate and 20 phr of plain magnesium hydroxide, respectively. The smoke density rates of above three systems were 65, 76, and 90, respectively.

Influence of Contents of Novel P-Br Flame Retardant on Flame Retardancy and Mechanical Properties of Epoxy Resin

2010, 24 (02): 92-95 ; DOI: 10.19491/j.issn.1001-9278.2010.02.020

Abstract ( 2097 )

The influences of contents of flame retardant 1, 3, 5-tri(5, 5-dibromomethyl-1, 3, -dioxaphosphorinanyl-2-oxy)benzene (FR) on the flame retardancy and mechanical properties of epoxy resin (EP) were studied. Compared with neat EP, when the content of FR was 15 wt %, the limited oxygen index of EP/ FR system increased from 25.0 % to 29.3 %, the system could pass UL 94 V-0 rating, the fire growth index decreased from 3.63 kW/(m2·s1) to 0.77 kW/(m2·s1), the total heat release amount index reduced from 1.89 MJ/m2 to 1.34 MJ/m2, while the residue ratio at 600 ℃ rose to 29.02 % from 18.54 %. However, the mechanical property of the composite became inferior, it's the tensile strength decreased from 62.04 MPa to 39.81 MPa and the impact strength decreased from 13.46 kJ/m2 to 10.13 kJ/m2.

Research on the Separation Method of Waste Plastic Films

2010, 24 (02): 96-99 ; DOI: 10.19491/j.issn.1001-9278.2010.02.021

Abstract ( 1946 )

Using water as a flotation agent, PVC film was separated from a mixture of PVC, PE,and PP films. The effect of flotation liquid density, temperature, solid content, content of wetting agent, stirring speed, and separation time on the recovery of PVC were studied. It was found that the optimal conditions were: flotation liquid density 1.04 g/cm3, separation temperature 30 ℃, the ratio of solid to liquid 1:50, content of wetting agent 0.2 wt %, stirring speed 50 r/min, the separation time 8 s, by which the recovery of PVC reached 98 %.

Design of Injection Mould for Two-color Cups with a Handle

Hui-Lan Zhou Chen-Chen Peng

2010, 24 (02): 100-102 ; DOI: 10.19491/j.issn.1001-9278.2010.02.022

Abstract ( 1597 )

A two-cavity, two-component injection mould with turn plate adiabatic extension nozzle was designed for production of two-color handled cup. The key issues of the design, structure and working process of the mould were introduced. The inner of the cup was molded in a whole cavity and the outer was molded in half-type cavity. The half split blocks were moved by hydraulic mechanism. The half split sliding blocks were used to shorten the height of cavity of semi product and the blocks were moved by slanted guide pillar core pulling mechanism. It was proved that the movement of the mold was reliable with low cost and the quality of the products was good.

Analysis and Simulation on the Electro-hydraulic System of the Ultra High Speed Injection Molding Machine

2010, 24 (02): 103-108 ; DOI: 10.19491/j.issn.1001-9278.2010.02.023

Abstract ( 1927 )

This article develops mathematical models of ultra-speed injects system about injection machine. The mathematical models are established by the proportion delivery valve, the proportion flow valve, the accumulator and the hydraulic carries. Otherwise, the investigation building up the system model and the analyzing dynamic characteristic by MATLAB. In the end of this paper point the key factor of speed control through dynamic characteristic.

Numerical Study on Distributive Mixing Performance in Pin Mixing Section of Single-Screw Extruder

Xiao-cui LI Jiong PENG Jin-nan CHEN

2010, 24 (02): 109-112 ; DOI: 10.19491/j.issn.1001-9278.2010.02.024

Abstract ( 2005 )

The mixing efficiency in the pin mixing section of a single-screw extruder was evaluated using the normalized mixing entropy. Nine different arrays of the pin mixing section were designed with the orthogonal design method. The isothermal flow field of polypropylene melt in the mixing section was calculated using a finite element method. The effects of the row number in a pitch length, the pin number in each row, and the pin height on mixing efficiency were discussed. It was found that the normalized mixing entropy increased along the extrusion direction. The best mixing efficiency was obtained by a configuration with five rows of five 12 mm high pins in a single screw pitch.