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2010, Volume 24 Issue 03 Publication date: 26 March 2010 Previous Issue Next Issue

Research Progress of ABS/Carbon Nanotubes Nanocomposites

Liang ZHOU DONGmei LI Ying YANG

2010, 24 (03): 1-10 ; DOI: 10.19491/j.issn.1001-9278.2010.03.001

Abstract ( 2109 )

Recent studies on nanocomposites of acrylonitrile-butadiene-styrene/carbon nanotubes (ABS/CNTs) have been reviewed. A detailed introduction was given on their preparation methods as well as their mechanical, electrical, radar absorbing, thermal degradation, and flame retardant properties. It was found that with addition of small amount of CNTs, the elastic modulus, tensile strength, and modulus of ABS were greatly improved; the electric resistivity was much lowered and reached the requirement of permanent antistatic standard. The composites possessed excellent radar absorbing ability and flame retarding performance. Comprehensive analysis on the influence of different types, addition amounts, and pre-treatments of CNTs on above-mentioned properties of ABS/CNTs nanocomposites was made and the corresponding mechanism was presented and discussed.

Research Progress of Halogen-free Flame-retardant Phosphorus-containing Epoxy Resins

Shaopeng TONG Guozhi XU

2010, 24 (03): 11-18 ; DOI: 10.19491/j.issn.1001-9278.2010.03.002

Abstract ( 1753 )

The halogen-free flame retardant phosphorus-containing epoxy resins have double flame retardant effect of gas phase and agglomeration phase for its phosphorus element. The materials do not produce continuable environmental contamination after decomposition. Therefore, they are widely researched as environment-friendly flame retardant materials. The thesis reviews that 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) epoxy resin system (including DOPO-containing epoxy resin, DOPO-based curing agent, DOPO-modified-polymer additive), phosphate-based epoxy resins(mainly including phosphate epoxy compounds, cyclic phosphate epoxy resin, phosphate curing agent), other curing system of phosphorus-containing, phosphazene epoxy resins and phosphorous-silicon epoxy resin. Their characteristics are introduced. It is summarized that the flame retardant properties and mechanism, thermal properties, the synergistic effect of phosphorus-nitrogen and fire retardant properties of phosphorus-silicon binary system.

Progress in Numerical Study on Polymer Extrusion Die Design

Jinnan CHEN Tao PENG

2010, 24 (03): 19-24 ; DOI: 10.19491/j.issn.1001-9278.2010.03.003

Abstract ( 1483 )

The progress in numerical design of extrusion dies was reviewed. In the early stage, when no slip condition was assumed, polymer extrusion process for PE-LLD, PE-HD, R-PVC, PP, ABS, PS, and rubber, were numerically simulated, based on which the extrusion dies of bar, tube, board, and structural section were optimally designed. Recently, effects of wall slip, die swell, and flow field were numerically studied. The improved design decreased die swell and enhanced the quality of the final products.

Morphology and mechanical property of PVC/MBS blends

Mingli CHU Zhe LIU Hongquan LI Ming CHEN Huixuan ZHANG

2010, 24 (03): 25-28 ; DOI: 10.19491/j.issn.1001-9278.2010.03.004

Abstract ( 1971 )

MBS core-shell graft copolymer was synthesized by grafting methyl methacrylate and styrene on poly(butadiene) (PB) rubber particles via seed emulsion polymerization. The MBS particles were introduced into PVC via melt blending and the effects of MMA and St contents in MBS on dispersion and mechanical property of the blends were investigated. With increasing MMA content, the dispersion of the particles was improved，the impact strength of the blends was increased giving high values above 1117 J/m. When the content of St was low, high impact strengths were still observed, however, too high styrene loadings was harmful to the toughness.

Study on the Microstructure and Thermal Properties of L-lactide and ε-caprolactone Copolymers

Yue LU Zuochun XIONG Shenglan ZHANG Chengdong XIONG Dongliang CHEN

2010, 24 (03): 29-33 ; DOI: 10.19491/j.issn.1001-9278.2010.03.005

Abstract ( 1715 )

L-lactide(L-LA) and ε-caprolactone(ε-CL) were copolymerized in bulk using stannous octoate as a catalyst. By varying the polymerization monomer feed ratios, copolymers with various compositions can be synthesized. The experimental and theoretical block average sequence lengths based on Bernoullian statistics were calculated from the 1H NMR spectra. With increasing amount of caproyl from 0.1 to 0.5, it is found that the experimental average sequence lengths of the lactidyl units (LeLL) decreased from 20.0 to 4.2, and the experimental average sequence lengths of the caproyl units (LeC) increased from 2.4 to 4.2. The thermal properties of the obtained copolymers were investigated by differential scanning calorimetry (DSC). While the amount of caproyl increased from 0.1 to 0.5, the melting point(Tm) decreased from 161.3℃ to 120.5℃; the heat of melting (△Hm) decreased from 31.5J/g to 8.0J/g; and the glass transition temperature decreased from 51.5℃ to -3.2℃.

Non-isothermal Crystallization Kinetics of Polypropylene / Polyamide 6 Blends In-situ Compatibilized with PAG

Shujun LIANG Wantai YANG

2010, 24 (03): 34-40 ; DOI: 10.19491/j.issn.1001-9278.2010.03.006

Abstract ( 1546 )

The non-isothermal crystallization kinetics of PP, PA6， and the blends of PP/PA6 compatibilized with a copolymers (PAG) of α-methyl styrene (AMS) and glycidyl methacrylate (GMA) was studied by means of differential scanning calorimetry(DSC). Jeziorny method was used to analyze the crystallization kinetics parameters. It showed that the peak crystallization temperatures and the crystallization heat enthalpies of both PP and PA6 in PP/PA6/PAG all decreased while the semi-crystallization time increased. These results demonstrated that there have some chemical reactions occured when PAGs were added into the blends. Within the cooling rate of 2.5～40 ℃/min, the amended Avrami model can well describe the non-isothermal crystallization process of PP，PA6，PP/PA6，and PP/PA6/PAG.

Study on Synthesis of a Super-water-absorbent Copolymer of Acrylic Acid and Acrylamide Incorporated with Attapulgite Clay Prepared under Microwave Radiation

Shuili LAI Feng CHEN HAN HAN

2010, 24 (03): 41-44 ; DOI: 10.19491/j.issn.1001-9278.2010.03.007

Abstract ( 1802 )

A super-water-absorbent copolymer of acrylic Acid and acrylamide incorporated with attapulgite clay prepared under microwave radiation using N , N′-methylenebis-acrylamide as a crosslinking agent and potassium persulfate and sodium bisulfite as an initiator.The effect of the mass ratio of acrylic acid to acrylamide , attapulgite clay amount, microwave reactor power and reaction time on the fluid absorption of the copolymer is studied. FTIR was also used to characterize the resultant. .The optimal reaction conditions are obtained as follows: weight ratio of acrylic acid to acrylamid to attapulgite clay is 15:3.5:1, the molar ratio of initiators is 1:1.; the amount of initiator is 0.6 % of the monomer's; the amount of the crosslinking agent N , N′-methylenebis-acrylamide is 0.05 % of the monomer's; the microwave reactor power is 600 W and the reaction time is 40s.

Rheological Behavior of Acrylonitile-styrene-acrylate Copolymer

Yanfang WANG Lingling CUI Baoliang XU Mouyong TENG

2010, 24 (03): 45-48 ; DOI: 10.19491/j.issn.1001-9278.2010.03.008

Abstract ( 2019 )

The rheological properties of acrylonitile-styrene-acrylate copolymer(ASA) have been studied by means of rheometer. The effect of shear rate, shear stress, and temperature on the viscosity of ASA was discussed. It showed that the apparent viscosity decreased and the non-Newton index increased with increasing temperature. The visco-flow activition energy decreased with the increasing of shear rate. The non-Newton index was less 1, indicating a typical pseudo-plastic nature of the melt of ASA copolymer.

Effect of Selective Localization and Migration of Inorganic Nanoparticles on Morphology and Properties of Polymer Blends

Jie YU Shijun HU Jianbing GUO Minmin ZHANG Shuhao QIN

2010, 24 (03): 49-54 ; DOI: 10.19491/j.issn.1001-9278.2010.03.010

Abstract ( 1637 )

The solid particles are well known to distribute unevenly in polymer blends and the factors that determine their distribution are discussed. The present review aims at summarizing the current knowledge on the phase behavior, phase morphology, mechanical property, electrically property, rheological behavior, crystallization, melting behaviors and optical property of polymer blends/layered silicate nanocomposites. A particular emphasis is given on how to control the particle localization in polymer blends through the competition between thermodynamic wetting of the solid by the polymeric phases as well as the kinetics related to the rate of mixing.

Study on Flame-retardant Property of Polyurethane Foam Using Cone Calorimeter

Baogang YU

2010, 24 (03): 55-59 ; DOI: 10.19491/j.issn.1001-9278.2010.03.011

Abstract ( 2062 )

The flame retarding ability of retardant additives including alumina trihydrate, bromine-containing, nitrogen-containing, and phosphorus-containing fire retardants for polyurethane foam was investigated by using cone calorimeter at a heat flux of 50kW/m2. The parameters such as time to ignition (TTI), peak heat release rate (PHRR), total heat release (THR), specific extinction area (SEA), and mass loss rate (MLR) were determined. Considering the comprehensive behavior, ammonium polyphosphate (APP) and melamine polyphosphate (MP) were considered the superior ones.

Effect of Polyamide 6 in Polypropylene/Microencapsulation Ammonium Polyphosphate

Zhiling MA Huipeng TANG

2010, 24 (03): 60-63 ; DOI: 10.19491/j.issn.1001-9278.2010.03.012

Abstract ( 2028 )

Polyamide 6 was introduced into PP/MAPP system as a synergetic char agent. When MAPP/PA6(w/w）=25/3, the intumescent degree and char yield of were 180.23㎝3/g and 72.11％, respectively, which contracted to 78.6㎝3/g and 61.96％when MAPP was used alone. The thermal analysis indicated that at low temperature zone, the weight loss of PP/MAPP/PA6 decreased and char yield increased obviously. However, at high temperature zone, the char degradation was accelerated, more flammable substance were formed that release more heat through burning. So the loading of PA6 should be appropriate. When PP/MAPP/ EPP/PA6(w/w/w/w) =75/25/7/3, its oxygen index was 34.7, the self -extinguishing time was 16s in horizon test, and the mechanical strength was 28.89 MPa.

Research on Injection Molding Technology of Ultra-thin Flower Pots

Yang ZHANG Yong XIN

2010, 24 (03): 64-67 ; DOI: 10.19491/j.issn.1001-9278.2010.03.013

Abstract ( 1470 )

Using Moldflow software, the injection molding of ultra-thin flower pot was simulated and analyzed. In order to overcome the defect of short shot, three approaches were compared by simulation. It was found that the use of claw-shaped gate could eliminate the short shot defect and thus improved the product quality.

Injection Molding of Two-color Electrical Enclosures

Dongmei LI Yan XU Jianbo JIA Shenbo WANG

2010, 24 (03): 68-71 ; DOI: 10.19491/j.issn.1001-9278.2010.03.014

Abstract ( 1402 )

Using professional software for mold flow analysis Moldflow/MPI, the filling process of two-color electrical enclosure was simulated. It showed that the optimal locations of both inner and outer enclosure were located at the center of undersurfaces. Air traps trended to occur at the edge of products; main warpage was presented as radial warpage. The filling time, cooling time, maximum injection pressure, and volumetric shrinkage were analyzed and thus optimized the injection process and molding die structure of two-color electrical enclosure.

Preaparation of PVC-g-DMC and Its Application in PVC

Yilan GE Qingshan LI Zhanquan CUI Zhongxue SUN Bin GUO

2010, 24 (03): 72-78 ; DOI: 10.19491/j.issn.1001-9278.2010.03.015

Abstract ( 1483 )

In this paper solid-phase suspension method was employed to synthesize a 2-Trimethylammonium ethyl methacrylate chloride (DMC) grafted PVC resin (PVC-g-DMC). The effect of initiator, monomer concentration, reaction temperature, and reaction time on the grafting degree was investigated, FT-IR and 1H-NMR confirmed the grafting structure. DSC showed that the glass transition temperature and melting point of PVC-g-DMC increased with increasing grafting degree. The crystallinity of the resin was determined using XRD. PVC-g-DMC was introduced intoi PVC as a mofifier. When the loading of PVC-g-DMC was 10 wt %, the tensile and impact strengths of increased by 45.1%, 76.63%, respectively, compared with un-modified resins. The inclusion of PVC-g-DMC also improved anti-bacterial properties of PVC.

Effect of Compounding Ratio of Two Different PVC Paste Resins Synthesized by Separate Process on the Viscosity and Stability of the Resultant PVC Plastisols

Yubi JI Guomin XU Minmin ZHANG Zhi HU Hong TAN

2010, 24 (03): 79-82 ; DOI: 10.19491/j.issn.1001-9278.2010.03.016

Abstract ( 1996 )

Viscosity and its stability over time of PVC plastisols were studied based on compounds of two different PVC paste resins, suspension polymerized ones (P1) and MSP-3 ones（P2）. P1 had a similar polymerization degree with that of P2. When the ratio of P1/P2 is 80/20, the plastisol exhibited the highest viscosity and worst stability.When the ratio of P1/P2 is 50/50, a lower viscosity and the best stability were observed. Different sequences of the blending of P1 and P2 led to the variation of the viscosity and its stability of the plastisols. While adding P2 to P1, the viscosity of the plastisols increased , and its stability became worse; the effect of particle morphology of the paste resin outpaced that of particle diameter. Nevertherless, while adding P1 to P2, the viscosity of the plastisols decreased , and its stability became better ; which attributed to the optimization of particle morphology of the paste resin and particle diameter.

Development Scenaria of Resins, Processing Technologies and Machines for Blow Molded Plastics Containers

Xue LIU Yuxia ZHANG

2010, 24 (03): 83-91 ; DOI: 10.19491/j.issn.1001-9278.2010.03.018

Abstract ( 1837 )

Recent development scenario of resins and additives, processing technologies and machines for blow molded plastics containers were reviewed, including innovative brand resins, polymer blends and copolymers; novel additives; up-to-date injection-blow molding machines, injection-stretch-blow molding machines, extrusion-blow molding machines and stretch-blow molding machines; and barrier-improving, microcellular foaming, thinning and lightening blow molding technologies. The listed resins covered bottle-grade polystyrene, polyoxymethylene, polyamide 6, poly(vinylidene flouride), poly(lactic acid) and polypropylene, etc. The mentioned blow molding machines contained all-electric machines, high-speed machines, energy-saving machines and coextrusion machines, and so on.

Effect of Spherical Sillca Particle Size and Their Matches on Flowability of Epoxy Molding Compound for IC Packaging

Mingshan YANG Yang LIU Linkai LI Dongxue LI

2010, 24 (03): 92-95 ; DOI: 10.19491/j.issn.1001-9278.2010.03.019

Abstract ( 2041 )

By means of matching filling of five grades of spherical silica with the particle size of 2μm, 3μm, 5μm, 10μm, and 20μm respectively, the epoxy molding compounds(EMC) for intergrated circuits(IC) were manufactured. Using classical particle accumulation theory, the particle distribution according with Dinger-Funk-Alfred equation was calculated by Matlab simulation software, and the optimal particle size formulations were obtained. Adding the mixed silica according to the above optimal formulations into epoxy resin, the EMCs were manufactured by twin-roll compounding at 95~105℃. Measurement of rotating and capillary rheometers showed that the matching filling of silica with different particle size could improve the flowability of EMC.

Study on Dispersity of Modified TiO₂ Particles in PVC

Meifang LUO Huanbing WANG Chunzhong LI

2010, 24 (03): 96-100 ; DOI: 10.19491/j.issn.1001-9278.2010.03.020

Abstract ( 1828 )

The PVC/TiO2 composites were prepared via melt blending. The dispersion of the modified TiO2 particles in PVC was investigated with SEM. The dispersion of the TiO2 particles in PVC and mechanical properties of the composites were related to the surface modification of TiO2, When surface treated with tetrabutyl titanate (Ti(OBu)4), γ-aminopropyltriethoxysilane (KH-550), or polymethyl methacrylate (PMMA). the TiO2 particles could be well dispersed in PVC, which increased the impact strength. As the content of PMMA-modified TiO2 particles was 2.5 phr, the izod impact strength of the composite was teo times that of neat PVC. However, when modified with SLS, the particles ggregated severely and thus the mechanical properties of the composite declined.

Study of Flame-retarding Mechanism on EVA Treated with Intumescent Flame Retardant by TG-MS

Jianzhong XU Jia SHI Jixing XIE Yunhong JIAO Yun SUN

2010, 24 (03): 101-104 ; DOI: 10.19491/j.issn.1001-9278.2010.03.021

Abstract ( 1612 )

The flame retardant and mechanical properties of intumescent flame retardant system（APP/PER/MCA/EVA）was investigated using limited oxygen index and tensile testing instruments, and its thermal degradation process under air atmosphere was studied by TG-MS. With a total loading of APP/PER/MCA (8/4/3) of 40wt %, EVA gave a limited oxygen index of 26 % and a tensile strength of 6.62 MPa. The initial decomposing temperature and weight loss of modified EVA decreased 100 ℃和10 %, respectively, compared with neat EVA. In addition, the fillers decreased remarkably the heat absorption, changed the composition of the thermal degradation products especially benzene was decreased obviously.

Design of Four-plate Injection Mold of Spur-helical Gears

Huilan ZHOU Xinjian ZHOU Mingcai LIU

2010, 24 (03): 105-107 ; DOI: 10.19491/j.issn.1001-9278.2010.03.022

Abstract ( 1464 )

Based on an analysis of the structure and process characteristics of spur-helical gear, the structure and working process of the injection mold with helical-gear demolding were introduced. In the present mold design, the helical-gear demolding was realize through a gear-cavity rotary mechanism, slide-pull was achieved by bevel guiding-post and half mold, and four-plate mold structure was used to finish three separating according to distance.

Study on Stretching Effect in Mixing Section of Two-rotor Continuous Mixers

Xia ZHANG Linsheng XIE Yulu MA

2010, 24 (03): 108-113 ; DOI: 10.19491/j.issn.1001-9278.2010.03.023

Abstract ( 1899 )

The 3-D non-isothermal flow field in mixing section of two-rotor continuous mixer was simulated by software POLYFLOW and was tested by PP/PS mixing. The fracture surface morphology of the samples was observed by scanning electron microscope (SEM) in order to study the flow field characteristics. It indicated that: the stretching effects in rotor convergence zone were stronger than those in positive or negative transportation zone in mixing process; the stretching effect of material near the top area of screw edge was stronger and those in the C zone was smaller in the same cross section; the convergent channel at the top area of screw edge provided intense stretching effect. In general, because of special structure of the rotor, material was stretched, fractured, and redistributed repeatedly during the mixing process, which promote dispersion mixing process.

Design of Injection Mould for Cars' Interiors Based on UG Software

Yanjuan LI Fang WANG Xiaodong LIU

2010, 24 (03): 114-117 ; DOI: 10.19491/j.issn.1001-9278.2010.03.024

Abstract ( 1517 )

The design of injection molds based on UG was exemplified by car's interiors with the emphasis on the parting mechanism including the designs of hole patch, parting lines, side parting, and core-pulling. The injection mold adopted two-cavities with balance layout, automatic falling of the cold material at point-gate, side parting, and core-pulling mechanisms. The purpose of automatic production was realized.