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2009, Volume 23 Issue 12 Publication date: 26 December 2009 Previous Issue Next Issue

The Research Situation of Ablative Property of Modified Phenolic Resin

2009, 23 (12): 1-5 ; DOI: 10.19491/j.issn.1001-9278.2009.12.001

Abstract ( 1491 )

In this paper, two types of modification methods to improve the ablative resistance of phenolic resin were reviewed, i.e., inorganic element and structural modifications. The inorganic element modification involved the introduction of boron or molybdenum elements, with the latter being more effective. The structure modification included the attachment of aryl phenol, benzoxazine, maleimide, cyano, or alkynyl groups. The synthesis and ablation resistance of the structural modified phenolic resins were summarized. These groups could generally improve the ablative resistance, however, the alkynyl group may resulted in higher curing temperature and was seldom employed.

Development of Chemical Modifying of Waste Expanded Polystyrene

2009, 23 (12): 6-9 ; DOI: 10.19491/j.issn.1001-9278.2009.12.002

Abstract ( 2063 )

The chemical modification of waste polystyrene(WPS) was summarized in this paper. The modifications could be categorized into two types: (i) The introduction of functional groups to the lateral benzene group of WPS via electrophilic substitution, i.e., sulfonation，halogenation，nitration, chloromethylation, and acylation; (ii) radical copolymerization between the benzyl of WPS and vinyl monomers including acroleic acid, acrylate, maleic, acetate, acrylonitrile, and propenol.

Investigation on Nonisothermal Crystallization Kinetics of Nylon 11/ Silica Nanocomposites

2009, 23 (12): 10-15 ; DOI: 10.19491/j.issn.1001-9278.2009.12.003

Abstract ( 1495 )

Polyamide 11 (PA11) and its nanocomposites with silica were prepared via in situ polymerization. The nonisothermal crystallization behavior of the materials was investigated using differential scanning calorimeter (DSC) with the data described with Jeziorny and Mo methods. Both Jeziorny and Mo methods described well the primary and secondary crystallization stages. It was found that the crystallization rate of the nanocomposites was lower than that of neat PA11. The activation energy of the nonisothermal crystallizations was calculated based on Huffman-Lauritzen theory, the activation energy of the nanocomposites was smaller than neat PA11.

Electromagnetic property of mutiwall carbon nanotube(MWCNTs) /Poly(p-phenylene sulfide)Composite in 0.5～18 GHz

2009, 23 (12): 16-19 ; DOI: 10.19491/j.issn.1001-9278.2009.12.004

Abstract ( 2582 )

Poly(p- phenylene sulfide) / muti-wall carbon nanotubes（MWCNTs）composites were prepared via melt compounding. The electromagnetic property of the composites with different contents of MWCNTs in the wave band from 0.5. to 18 GHz were researched . It was found that the real part and imaginary part of permittivity increased with increasing the content of MWCNTs. The real parts of permittivity decreased with increasing frequency, in the frequency range of 0.5～18 GHz. However, the magnetic conductivity stayed around the level of one (μ= 1). The reflection loss and absorbing peak frequency were calculated from the measured data。It was found that the composites showed excellent microwave absorbing characteristics at the frequency range of 0.5～18 GHz，with matching thickness was 2 mm , the maximum reflection loss was about - 31.5 dB for the absorber, the bandwidth corresponding to the reflection loss below - 10 dB was more than 2.2 GHz when the MWCNTs content was 7 %.

Synergistic Toughening of Chlorinated Polyvinyl Chloride (CPVC) Blends

Wen-hui LI Cheng-ya HUANG Xiao-ling LU Ran ZHAO

2009, 23 (12): 20-25 ; DOI: 10.19491/j.issn.1001-9278.2009.12.005

Abstract ( 1956 )

The synergetic toughening effect of nitrile rubber (NBR), CaCO3, and acrylonitrile-butadiene-styrene copolymer (ABS）for chlorinated polyvinyl chloride (CPVC) was studied. When the contents of NBR and ABS were 5 and 4.5 phr, respectively, an impact strength of 74.1 kJ/m2 was obtained, which was 2.5 and 4.4 times those of the systems containing NBR or ABS alone. Optical microscopy showed that core-shell NBR phase dispersed very well. SEM micrographs indicated that the impact fracture of CPVC toughened with NBR and ABS mainly followed the ductile failure.

A generalized viscosity for generalized Newtonian fluids

peter.lim W.N. Song

2009, 23 (12): 26-30 ; DOI: 10.19491/j.issn.1001-9278.2009.12.006

Abstract ( 1493 )

A generalized viscosity model was proposed for generalized Newtonian fluids, which was expressed as a function of the invariants of stress and strain rate tensors. Assuming the independency of the second and third invariants of the rate of strain tensor, this model described well various shear and extensional as well as complex flows. When applied to steady-state simple or extensional flows, the obtained viscosities were agree with those traditionally defined.

Study on Synergistically Toughening Effect of Nano-BaSO4/MBS Composites

christina.guo

2009, 23 (12): 31-34 ; DOI: 10.19491/j.issn.1001-9278.2009.12.007

Abstract ( 2033 )

The synergistic toughening of PA6 with MBS and nano-BaSO4 were studied. The impact strength, tensile strength, melt flow index, and instantaneous energy absorption curves of the PA6/MBS/BaSO4 composites were determined and the micro-structure of the impact fractured surface was studied. The polyamide composites toughened with MBS and nano-BaSO4 may achieved an impact strength of 85.9 kJ/m2, which was 48 % higher than that of PA6/MBS pre-toughened system. The melt flow rate was also improved, and the tensile strength changed unconspicuously.

Study on dispersivity of nano-silica in process of preparation of filled silicone rubber membranes

2009, 23 (12): 35-38 ; DOI: 10.19491/j.issn.1001-9278.2009.12.008

Abstract ( 1431 )

Using PET as the support, nano-carbon white filled polydimethylsiloxane (PDMS) as the dermic layer, a separation membrane for separating ethanol from water was prepared. The factors effecting on the dispersion of nano-carbon white in silicone rubber was studied. It was found that an amount of ES and heptane may improve the dispersion of nano-carbon white. When the 5 wt % of nano-carbon white was introduced, the tensile strength of PDMS film increased from 0.368 to 1.828 MPa.

Properties of Nylon 6 Composite Modified by the P(St-AM)/OMMT Core–shell Structures

Wei Wu

2009, 23 (12): 39-43 ; DOI: 10.19491/j.issn.1001-9278.2009.12.009

Abstract ( 1448 )

Polystyrene/polyacrylamide/organic montmorillonite core-shell particles were synthesized through emulsion polymerization and used to modify polyamide 6, their influence on mechanical properties, processability, crystallization behavior, and thermal stability of PA6 composites was investigated. By the inclusion of the core-shell particles, the flexile strength and modulus were increased by 1.44 and 3.46%, respectively, based on neat PA6. The core-shell particles acted as nucleating agent, which increased the crystallization temperature of PA6by 8.5 oC and the degree of crystallinity by 3.3 %. The PA6 composites also showed a good thermal stability and processability, the melt flow rate was increased by 118 %.

Nonisothermal Crystallization Behavior of ethylene-tetrafluoroethylene Copolymer

BAO Yong-Zhong

2009, 23 (12): 44-47 ; DOI: 10.19491/j.issn.1001-9278.2009.12.010

Abstract ( 2051 )

Nonisothermal crystallization behavior of ethylene-tetrafluoroethylene copolymer (ETFE) was studied by DSC and polarizing microscope. DSC data was dealed with Mo and Kissinger method. The results indicated that the maximal crystallization temperature of ETFE was decreased and the range of crystallization temperature became broader as the cooling rate incresed.The crystallization process could be divided into three phases as the nucleation period, primary crystallization phase in which nucleus grew into sphere crystals, and secondary crystallization phase in which sphere crystals contacted mutually and grew continually.The activation energy of nonisothermal crystallization of ETFE was increased with the increase of C2F4 content in ETFE.

Study on the ratio of the hollow glass bead modified epoxy resin based on the uniform design

Huijian Li Wei Yu

2009, 23 (12): 48-51 ; DOI: 10.19491/j.issn.1001-9278.2009.12.011

Abstract ( 2049 )

Based on uniform design experiments, the effects of hollow glass beads (HGB), coupling agent, dibutyl phthalate (DBP), and curing agent on the uniaxial compressive strength were investigated. Through analysis the effect of the main 4 factors, HGB, on the compressive strength of the composite. It was found that the compressive strength of the composites decreased with increasing content of HGB, and first increased and then decreased with increasing content of coupling agent, first decreased and then increased with increasing content of DBP and curing agent. The optimal recipe of HGB, coupling agent, DBP, and curing agent was found to be 1.5, 0.1, 6.5, and 95 phr, respectively.

Resistivity-Temperature Behavior of CB-Filled EVA/HDPE

2009, 23 (12): 52-55 ; DOI: 10.19491/j.issn.1001-9278.2009.12.012

Abstract ( 2151 )

Abstract: The foamed conductive composites of specially conductive carbon black（HG-1P）-filled ethylene-vinyl acetate (EVA)/high-density polyethylene (HDPE) were prepared by the methods of blending on the mixer and mold foaming in this thesis. The vadose threshold value, bubble structures, and resistivity-temperature behavior of the composites and the influences of different proportion of EVA/LDPE, the foamer and the cross-linker on the electric behavior of the composites were investigated.The results showed that EVA/HDPE conductive foamed composites filled with HG-1P had ideal bubble structures and the composites had good switching characteristics, and displayed clear negative temperature coefficient (NTC) effect through resistivity tests at the increasing temperature.

The Study Of plasticized PVC/natural mineral composites which can emit negative ions

2009, 23 (12): 56-59 ; DOI: 10.19491/j.issn.1001-9278.2009.12.013

Abstract ( 1879 )

PVC paste was filled with Liesegang pattern six-rings rock powder forming a composite. Gravimetric analysis showed that the decomposition temperature of the six-rings rock was above 600 ℃. The rock powder was finely dispersed in PVC paste with a particles size about 600 nm. When the content of the rock powder was 3 wt%, the release rate of anion was above 1500 ions/cm3, which met the standard of WHO.

The Optimum Method on Craft Parameters of Plastic Injection Based on Synthesis Relation degree

HUANG Feng-Li

2009, 23 (12): 60-64 ; DOI: 10.19491/j.issn.1001-9278.2009.12.014

Abstract ( 1906 )

In order to control two factors in plastic injection molding, warpage and shrinkage, an optimization method for the molding parameters was proposed based on correlative degree, Kriging model, and adaptive genetic-ant algorithm. The definition and calculation method of correlative degree were defined first, and the approximate model based on Kriging model and genetic-ant algorithm were introduced. In the case of plastic injection molding of fruit plate, the range of the technical parameters were first determined through orthogonal experiments, a approximate model was formulated based on Hyper-Latin square experiment and Kriging method, which was optimized via genetic-ant algorithm. The obtained parameters could well be applied to practical injection molding.

Study on the mechanism of sulfur-containing aryl polyphosphonate as flame retardant for PET

2009, 23 (12): 65-71 ; DOI: 10.19491/j.issn.1001-9278.2009.12.015

Abstract ( 2083 )

The flame retarding mechanism of a sulfur-containing polyphosphonate, poly (9, 10-dihydro-9-oxa-10- (2, 5-dihyroxyphenyl) phosphaphenanthrene-10-oxide) thiophenylphosphonate (PDPTP) in PET was studied through the analysis on the products of thermal degradation using PY-GC-MS, TG/FT-IR and XPS. It showed that the presence of PDPTP promoted the formation of char and delayed its decomposition. Most sulfur species in PDPTP volatized at lower temperature in the form of SOx, which diluted the flammable gases and thus retarded the fire. However, the volatization of phosphorus species mainly occurred in the second stage of decomposition, which generated small molecular compounds containing P=O and P-H bonds. Besides, PY-GC-MS showed that PDPTP strongly retarded the deep pyrolysis of PET, hence reduced the yield of small molecular flammable compounds. According to XPS, the phosphorus species of PDPTP accumulated on the carbonaceous polymer surface in the form of phosphoric acid or metaphosphoric acid, which acted as an efficient dehydrator and promoted the charring of polymer surface.

Study on Flame Retardant Synergism of MRP, MH and EG in HDPE composites

2009, 23 (12): 72-76 ; DOI: 10.19491/j.issn.1001-9278.2009.12.016

Abstract ( 1987 )

In this work, a flame retardant high density polyethylene (PE-HD) composite containing microencapsulated red phosphorus (MRP), magnesium hydroxide (MH), and expandable graphite (EG) was prepared via melt extrusion, which was characterized using LOI, UL 94, FT-IR, Raman, TG?DTA, SEM, and tensile testing. The possible flame retardant mechanism in the composites was proposed. It was found that EG alone possessed poor efficiency in flame retarding. However, when combined with MRP and MH, the flame retardancy was obviously emhanced. When PE-HD/ MH /MRP /EG = 100/35/15/5 in mass, the limited oxygen index of the composite was 28.5 %, vertical firing ranked UL 94 V-0. SEM showed that PE-HD was compatible with EG, but not with MRP and MH.

Modification of Polypropylene by Waste of Plastics Multilayer Plates

YOU Chang-Jiang Yi-Zheng Zeng Min Fang Jian-Xiong Li

2009, 23 (12): 77-81 ; DOI: 10.19491/j.issn.1001-9278.2009.12.017

Abstract ( 2179 )

PP was filled with powder of waste plastic multilayer plates(GFRP), a coupling agents and a compatibilizer forming a composite, which was characterized using DSC，SEM, and the mechanical testings. When the content of GFRP (modified by 1 wt % KH570) and the compatibilizer was 20 phr and 2 phr, respectively, the impact strength of the composites increased markedly, the flexural strength and modulus also increased based on neat PP. SEM indicated that plasticity deformation occurred during fracture process of the composite. DSC showed that the addition of GFRP didn't changed crystal form of PP.

Test Method of Recovery Time for Slow Recovery Foam

[吴昊] [Wu Hao]

2009, 23 (12): 82-86 ; DOI: 10.19491/j.issn.1001-9278.2009.12.018

Abstract ( 2110 )

The definition, history, and application of slow recovery foam were reviewed. The national standard "Slow recovery foam - determination of recovery time" was introduced. The determining method, precision and bias of the recovery time and their influencing factors were studied.

computer Pro/E designed software for designing manifold-type mold

2009, 23 (12): 87-91 ; DOI: 10.19491/j.issn.1001-9278.2009.12.019

Abstract ( 1922 )

A manifold-type extrusion sheet mould was designed based on the Pro/E software. In order to get the optimized parameters, an insert "Plastic Advisor"was used to analyze the effect of the manifold shape and the sector size on the flowing state in the mould. It was found that the optimal end diameter of the manifold was XX mm and the optimal fan-shaped area height was 2 mm. These values were agree with those obtained from traditional calculations

Development of Hot Runner Injection Mold for Mineral-Water Bottle Lids

Shu-Zhen Li Zhi-Liang Liao

2009, 23 (12): 92-96 ; DOI: 10.19491/j.issn.1001-9278.2009.12.020

Abstract ( 2062 )

Development of hot runner injection mold for mineral -water bottle lids was carried out based on CAD/CAE technology in this paper. Moldflow was adopted to analysis the best gate location, molding windows, flow, and the results can be used as reference for the mold design and process parameters setting. The key issues of the design of the hot runner system and the structure and movement principle of t sequential demoulding mechanism were illuminated in details. Practice has proved that the movement of the mold is reliable, productive efficiency is high and the quality of products is stable.