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2013, Volume 27 Issue 02 Publication date: 26 February 2013 Previous Issue Next Issue

Current Status of Recycling and Reuse of Carbon Fiber Composites

2013, 27 (02): 1-7 ; DOI: 10.19491/j.issn.1001-9278.2013.02.001

Abstract ( 1387 )

Currently, the physical, chemical and energic recovery are the main methods in recycling and reuse of carbon fiber reinforced plastics (CFRP). In particular, the chemical method is the best commercial way, which includes oxidation fluidized bedding, supercritical fluids，and pyrolysis methods. The technology, features, and application of these methods were introduced, the main problems in the recycling process and the practicable measures were analyzed.

Research Progress in Fabrication of Biodegradable Polycaprolactone Foams

2013, 27 (02): 7-13 ; DOI: 10.19491/j.issn.1001-9278.2013.02.002

Abstract ( 1583 )

The latest progress in the preparation methods of biodegradable PCL foam was reviewed, including supercritical gas foaming, thermally induced phase separation, solvent casting/particle leaching, and rapid prototyping. In addition, the problems of PCL foaming at the present stage were discussed and the prospects were forecasted.

Research Progress in Moisture Absorption Behavior of Polymermatrix Composites

WANG Bing Ling LI

2013, 27 (02): 14-18 ; DOI: 10.19491/j.issn.1001-9278.2013.02.003

Abstract ( 1599 )

Research progress in the moisture absorption behavior of the polymermatrix composites was reviewed in this paper. The moisture absorption mechanism of the composites and the main factors that affect the moisture absorption were elaborated. Moisture diffusion model, dewetting behavior prediction, and life prediction model were introduced.

Effect of Bicycle[2,2,1]hept-5-ene-2-benzoylamide-3-carboxylate Salts on the Mechanical and Crystallization Properties of Isotactic Polypropylene#br#

2013, 27 (02): 19-25; DOI: 10.19491/j.issn.1001-9278.2013.02.004

Abstract ( 91 )

Study on Properties of 2hydroxypropyl (2hydroxyethyl) Carbamate Chain Extension Polyurethane Elastomers

WANG gai-jing

2013, 27 (02): 26-29 ; DOI: 10.19491/j.issn.1001-9278.2013.02.005

Abstract ( 1099 )

Polyurethane elastomer was synthesized with diphenylmethane diisocyanate and poly εcaprolactone glycol/PEPA using 2hydroxypropyl (2hydroxyethyl) carbamate (HPHEC) or 1, 4butanediol as a chain extender, The product was characterized using differential scanning calorimeter(DSC), dynamic mechanical analyzer(DMA), electronic universal testing machine, and rubber resilience tester. It showed that gel time of polyurethane elastomer based on HPHEC was 3 times that of based on 1, 4butanediol. Tear strength of polyurethane elastomer based on HPHEC increased 10 %~ 25 %, and the glass transition temperature (Tg) and dynamic loss tangent (tanδ) also increased.

Study on Preparation and Properties of Epoxy/Resin Micronizeddicyandiamide Composite

2013, 27 (02): 30-33 ; DOI: 10.19491/j.issn.1001-9278.2013.02.006

Abstract ( 1200 )

A latent and mediumtemperature cured epoxy resin system was prepared from epoxy/ micronizeddicyandiamide/FH1. Polarizing microscope revealed that the micronized dicyandiamide could be welldistributed and kept stable in epoxy. The initial curing temperature was decreased about 40~50 ℃compared with that based on nonmicronizeddicyandiamide. The optimal mechanical properties of the resin were flexural strength 56.3 kJ/m2, tensile strength 91.4 MPa, elongation at break 4.6%. For the composites reinforced with fiberglass, the retention rate of mechanical properties at wetting condition was over 70 %.

Preparation and Properties of Heatinsulation and Transparency PVB/NanoATO Composite Films

Zhang Dongliang

2013, 27 (02): 34-39 ; DOI: 10.19491/j.issn.1001-9278.2013.02.007

Abstract ( 1333 )

Nano antimony tin oxide (ATO) was treated with silane coupling agent and hypersonic dispersed in ethanol, subsequently introduced into polyvinyl butyral (PVB). A series of transparent and heatinsulating film was prepared. The microstructure, morphology, and properties of the film were studied using FTIR, UV/VIS/NIR, SEM, and TG. The nanoATO was finely dispersed in PVB. The mechanical properties and heat resistance of the composite film were improved, especially the tensile strength was increased to about 2 times that of PVB. The visible light transmittance of the film containing 1 phr nanoATO was higher, and the thermal conductivity was 0.218 W/(m·K). The air temperature in the insulation box with this composite film as cover plate was decreased by 5.2℃ compared with neat PVB film. The thermal reflectivity in near infrared region was 60 %~86 %, the transparency, heatinsulation, and antiultraviolet were also good.

Study on preparation and properties of Dynamic crosslinked PP/EVA blends

2013, 27 (02): 40-43 ; DOI: 10.19491/j.issn.1001-9278.2013.02.008

Abstract ( 1186 )

In paper, dynamic crosslinking was applied to epoxy resin polypropylene (PP)/ ethylene-vinyl acetate copolymer (EVA) system, and prepared the dynamic crosslinked PP/EVA blends. Effect of dynamic crosslinking on torque of PP/EVA blends was studied by Hakke Rheometer, Influence of the content of DCP and EVA on mechanical properties of dynamic crosslinked PP/EVA blends was investigated and the vicat temperature of blends was also studied. The results showed the torque of PP/EVA blends torque increased firstly and then decreased by adding DCP, the suitable content of DCP is 1 wt% according to EVA content. The impact properties of blends increase obviously, but tensile properties decrease slightly with increasing of EVA content. A small amount of dynamic crosslinked EVA particles contribute to the crystallization of the PP in the blends, and increase the vicat temperature of blends.

Non-isothermal Crystallization Kinetics and Dynamic Mechanical Properties of Polyoxymethylene/Reactable Nano-SiO2 Composites

2013, 27 (02): 44-50 ; DOI: 10.19491/j.issn.1001-9278.2013.02.009

Abstract ( 1128 )

Polyoxymethylene/reactable nanoSiO2 (RNS) composites were prepared by melting blending. The nonisothermal crystallization behavior of POM and its composites were studied with differential scanning calorimetry (DSC) and the effect of nanoSiO2 was explored. Nonisothermal crystallization kinetics was described using Jeziorny and Mo methods. The RNS played a role of heterogeneous nucleation in the POM matrix, however, it resisted the diffusion of the segments. The net result was a lower crystallization rate  and longer crystallization halftime. The Avrami exponent n decreased, which indicated that RNS had changed the growth mechanism of POM. Dynamic mechanical analysis (DMA) indicated some improvements in the storage modulus with the addition of RNS. The tanδ peaks signifying the glasstransition temperature of POM shift to higher temperature, implying some strong interaction between nanoSiO2 and POM.

Study on Preparation and Property of Polyimide Modified Epoxy Resins/Glass Fiber Thermally Conductive Composite Filled with Al₂O₃ Particles

Ivan

2013, 27 (02): 51-55 ; DOI: 10.19491/j.issn.1001-9278.2013.02.010

Abstract ( 1046 )

Thermally conductive composite reinforced by glass fiber was prepared by heatpress molding, using polyimide modified epoxy resin as a matrix, alumina modified by KH550 as thermal conductive filler. The thermal, mechanical, and dielectric properties were studied. It showed that thermal conductivity of the composites increased with increasing content of Al2O3. When the content of Al2O3 reached 50 %, the thermal conductivity was up to 1.239 W/（m·K）. The impact and bend strengths increased first then decreased. When the content of Al2O3 was 20 %，the ultimate values were 376.3 kJ/m2 and 912.6 MPa, respectively. The composites modified using polyimide possessed good dielectric properties, thermal stability, and thermal aging resistant.

Effect of Shell Thickness of PB-g-SAN Copolymer Coreshell Impact Modifier on Toughening SAN Resins

2013, 27 (02): 56-59 ; DOI: 10.19491/j.issn.1001-9278.2013.02.011

Abstract ( 1061 )

PB-g-SAN copolymer prepared via seeded emulsion polymerization were meltblended with SAN resin forming an ABS resin. The shell thickness of PBgSAN copolymer was found to be the most important factor for the toughness of ABS resin. When the shell thickness was greater than a critical value of 117 nm, the modulus of these coreshell particles was too high to be flexible, and thus not efficient as rubbery modifiers. On the other hand, when the shell thickness was less than another critical value of 32 nm, the particles was not fully covered by the shell, the particles could not toughen SAN resin efficiency. When the shell thickness of particles was between 32 nm and 117 nm, the toughening of SAN was observed.

Preparation of Efficient Prolongreleased Aromatic Plastics with Fragrance Microcapsule

CHU Hong

2013, 27 (02): 60-64; DOI: 10.19491/j.issn.1001-9278.2013.02.012

Abstract ( 1103 )

Uniform solid fragrance spheric microcapsules with satisfied fluidity were prepared via insitu polymerization using ureaformaldehyde resin as a wall material in the presence of OP10 and hydrochloric acid (1∶50) as emulsifier and catalyst. Embedding rate, morphology, and fragrance longevity were studied using high precision thermal balance, scanning electron microscope, and optical microscope. The embedding rate reached 32 %. The asprepared microcapsules performed thermo stability and controlledrelease behavior. The fragranced plastics prepared with such microcapsules was proved to be scented stably and strongly with its longevity above 1 year. The weight loss of fragrance during the process was less than 10 %.

Research on Drying Process of PVB Casting Film

WEN Bianying

2013, 27 (02): 65-68; DOI: 10.19491/j.issn.1001-9278.2013.02.013

Abstract ( 1190 )

A series of PVB film was prepared via solution casting with hot plate drying. The effects of drying temperature, initial casting layer thickness, solution concentration, and content of filled conductive particle on the drying rate were investigated. It indicated that all the four factors had significant effect on the drying rate of the casting film, in which a higher drying temperature, a thinner initial casting layer as well as lower solution concentrations was beneficial to the improvement of drying rate, while the adding of filler particles reduced the solvent's relative content, which was not conducive to the improvement of the drying rate.

Non-isothermal Simulation of the Inflation Process in Extrusion Blow Molding of High Density Polyethylene Drum

LI Jing Jiong ＰＥＮＧ Shali Liu

2013, 27 (02): 69-73; DOI: 10.19491/j.issn.1001-9278.2013.02.014

Abstract ( 1125 )

The computational fluid dynamics software Polyflow was used to simulate the inflation process of extrusion blow molding under nonisothermal condition. The influence of inflation pressure was analyzed. It showed that the lower crystallinity degree resulted from higher cooling rate. The contact time increased with increasing inflation pressure. The weld seam weakness was more serious with a higher inflation pressure. Considering the comprehensive effect of the efficiency and weld seam weakness, the appropriate inflation pressure was around 0.6 MPa.

Three Dimensional Viscoelastic Numerical Research of Die Swell in Halfclub Coextrusion Processes

2013, 27 (02): 74-79 ; DOI: 10.19491/j.issn.1001-9278.2013.02.015

Abstract ( 1086 )

Using finite element method, a threedimensional nonisothermal numerical model was established based on PTT constitutive equation for halfclub coextrusion processes. The Arrhenius equation was applied to express the temperaturedependent transport properties. The coextrusion process of two different polymer melts was simulated, and the key to the study was the influence of interface position at die entry (r value) on die swell and interface position. It showed that the secondary flow of the die exit was weakened, and the die swell ratio was reduced with increasing r value. The interface position was stable in the die and at the die exit when r value made the two melts entrance area equal， and the melt inlet volumetric flow rate was equal.

Study on Preparation of Poly(lactic acid)/Polypropylene Blends and Its Foaming Bahvior

LIU Wei Yuxia ZHANG

2013, 27 (02): 80-85 ; DOI: 10.19491/j.issn.1001-9278.2013.02.016

Abstract ( 1298 )

This paper studied on foaming behavior of Poly(lactic acid)(PLA)/ Polypr -opylene(PP) Composites which were preparated with Maleic anhydride(MAH) -grafted PP(MAH-g-PP) as a reactive compatibilizer. Thermal and rheological behaviors of PLA/PP Composites were investigated using differential scanning calorimetry and dynamic rotary rheometer, respectively. Morphology of impact–fractured and foamed samples was observed by scanning electron microscopy. Compatibility of PLA/PP composites was improved gradually with rising addition of MAH-g-PP，which could promote the growth rate of PLA crystallization and improve the melt strength of PLA/PP composites greatly, and that’s why foaming behavior was enhanced.

Flame retardancy of Halloysite and Intumescent Flame Retardant on Polypropylene

2013, 27 (02): 86-89; DOI: 10.19491/j.issn.1001-9278.2013.02.017

Abstract ( 1186 )

halloysites were introduced into PP/IFR composite containing ammonium polyphosphate (APP) and pentaerythritol (PER). Limiting oxygen index (LOI), cone calorimeter test (CCT) and thermal gravimetric analysis (TGA) were used to characterize the flammability and thermal behaviour of PP composites. The morphology of the char was observed and analyzed by scanning electron microscope (SEM). It has been found that there exists a synergism between IFR and halloysite in improving the fire performance of PP. The composite containing 2phr HNTs has a LOI value of 32%, UL-94 test can reach V0 level and heat release rate (HRR) can lower to 222kw/m2. SEM results show that 2phr HNTs is the optimal loading in the composites and can provide the best flame retradant result.

Flame Retardancy of Phosphate/Inorganic Flame Retardant Under Microparticle and Mixture Blends

2013, 27 (02): 90-95; DOI: 10.19491/j.issn.1001-9278.2013.02.018

Abstract ( 1164 )

Three caged phosphate (trimer) microparticles were mixed magnesium hydroxide (MH), aluminium hydroxide (ATH), and silicon dioxide, and formed three composite flame retardants. The trimer was also encapsulated with above inorganic substances, which formed three capsule flame retardants. The flame retardancy of the two types of flame retardants in epoxy resin(EP) was compared in terms of limiting oxygen index, vertical burning tests (UL94), and thermal gravimetric analysis (TGA). It showed that the function provided by the blends was better than that of the capsules. The epoxy resin loaded with 20 wt% flame retardant (17 %trimer and 3 % inorganic substance) gave rise to limiting oxygen index to 32 %, and UL94 reach V0 rating. Whereas those based on the same loading of capsules were only 24 % and UL94 V2.

Research Progress in the Separation of Waste Plastics by Forth Flotation

2013, 27 (02): 96-102; DOI: 10.19491/j.issn.1001-9278.2013.02.019

Abstract ( 1541 )

The history and recent advances of plastics flotation were reviewed in this paper. Based on the mechanism of plastics flotation, the methods of selectively plastics wetting could be divided into wetting through adsorption, surface oxidation, wetting through absorption, and gamma flotation. At present, the developed methods of plastics flotation were mainly gamma flotation, flotation by physical conditioning and flotation by chemical conditioning, which are based on liquidvapor surface tension control, surface modification through physical techniques and adsorption of wetting agents, respectively. The methods of physical conditioning included such techniques as plasma treatment, flame treatment, ozone oxidation, particle control, wet oxidative chemical reactions and corona discharge. The common wetting agents used in chemical conditioning were methylcellulose, calcium lignosulphonate, and tannin.

Application of Finite Element Method in Barrel Design of Twin Screw Extruders

Tao PENG Zhaoyang JIA Jingfeng LI

2013, 27 (02): 103-109; DOI: 10.19491/j.issn.1001-9278.2013.02.020

Abstract ( 1260 )

The thermalstructure analysis for barrel of twin screw extruder was carried out using ANSYS software. The thermal deformation of three barrel and initial barrel was compared. It was concluded that increasing the thickness of the barrel or changing the channel could decrease the barrel deformation. On the base of single barrel deformation, the associated deformation influenced by temperature difference between neighbor barrels was analyzed. All the results had certain significances in studying whole barrel deformation of twin screw extruder.

Moldflowbased Design of Injection Mould for Pivot

Zhang Zheng

2013, 27 (02): 110-114; DOI: 10.19491/j.issn.1001-9278.2013.02.021

Abstract ( 1138 )

Pivot was taken as a sample. The CAE modeling of plastic was expounded. With software Moldflow, the optimal gate location was obtained, and the processing parameters of injection mould were optimized, and design plan for injection system was determined. By simulating the flow, cooling and warp age, the rationality and reliability of the design plan were conformed, which constituted a basis for the design of pivot.