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2017, Volume 31 Issue 09 Publication date: 26 September 2017 Previous Issue Next Issue

Research Progress of Flexible Copper Clad Laminates

2017, 31 (09): 1-10; DOI: 10.19491/j.issn.1001-9278.2017.09.001

Abstract ( 364 )

This paper reviewed the research progress of flexible copper clad laminates (FCCL), which covered their development history, classification, composition, market share and manufacturers. Copper foils, polymer films and adhesives as the base materials for FCCL were also introduced. Particularly, the research progress in polyimidebased FCCL was also presented. Based on the analysis of the production technology of FCCL and the polyimide films used, this paper pointed out the current existing problems and development direction in the field of FCCL.

Research Progresses of Anion Exchange Membranes Based on Poly(phenylene oxide)

2017, 31 (09): 11-21; DOI: 10.19491/j.issn.1001-9278.2017.09.002

Abstract ( 313 )

This paper overviewed the issues of electrical conductivity for poly(phenylene oxide) (PPO)-based anion-exchange membranes Alkaline resistance of this type of membranes based on PPO was introduced, and effects of the main chain, functional groups and structure of silane coupling on the performance of these membranes were also analyzed Finally, some resolutions for the development of high-performance PPO-based anionexchange membranes were proposed.

Research Progress and Industrial Present Status of Starch-based Plastics

2017, 31 (09): 22-29; DOI: 10.19491/j.issn.1001-9278.2017.09.003

Abstract ( 685 )

This article reviewed the modification methods of starchbased plastics and their industrial present status in China. The article also provided an overview on modification methods of starches and research progress in the blending modification of starches with traditional plastics, biodegradable plastics, and natural materials in the last three years. These plastics covered polyethylene, poly(vinyl alcohol), poly(lactic acid), poly(butyleneadipate terephthalate), and polycaprolactone.

Study on Thermal Stability Systems in Soft Poly(vinyl chloride)

2017, 31 (09): 30-35; DOI: 10.19491/j.issn.1001-9278.2017.09.004

Abstract ( 478 )

This paper reported an investigation on the complex effects of liquid/solid organ tin, Ca/Zn composite, rare earth stabilizers and layered double hydroxides (LDHs) as an auxiliary stabilizer on the thermal stability and mechanical properties of soft poly(vinyl chloride) (PVC).Static and dynamic thermal stabilities were characterized by thermal aging test, thermogravimetric analysis and Haake torque rheometer.The results indicated that the use of solid organ tin could lead to a high initial stability and good transparency for soft PVC, whereas the Ca/Zn composite stabilizers made PVC a longterm stability and excellent mechanical properties.Combination of the Ca/Zn composite stabilizers and LDHs can not only improve the thermal stability of PVC, but also enhance its mechanical properties and flame retardancy.

Preparation of Ethylene-vinyl Acetate/Polyacetal Thermoplastic Elastomers

2017, 31 (09): 36-42; DOI: 10.19491/j.issn.1001-9278.2017.09.005

Abstract ( 478 )

An ethylenevinyl acetate/polyoxymethylene thermoplastic elastomer (TPV) was prepared by dynamic vulcanization method using Luperox231/HVA-2 mixture as a vulcanization system.Compared with classical EVA/POM blends, comprehensive mechanical properties of the TPV could be improved significantly, and its tensile strength reached around 12 MPa with low elongation at break.The experiments also suggested that screw speed and processing temperature of the extruder influenced mechanical properties of TPV.To prepare the TPV with good performance, the screw speed and temperature should be set at 250 r/min and 145~175 ℃, respectively.The resultant TPV exhibited a decrease in tensile strength, elongation at break and D-Shore hardness with an increase of Luperox231 concentration, and however its tensile strength and permanent deformation presented a decreasing trend at first and then increasing with increasing concentration of HVA-2.

Effects of Surface Treatment on Properties of Continuous Carbon Fibers

2017, 31 (09): 43-47; DOI: 10.19491/j.issn.1001-9278.2017.09.006

Abstract ( 501 )

Surfaces of continuous carbon fibers (CCF) were modified by KMnO4, HNO3, electrochemical oxidation and ultrasonichydrogen peroxide combined oxidation.Surface morphology, wettability, impregnation and multifilament tensile strength of CCF were investigated.Scanning electron microscopy, inverse gas chromatography, and electronic tensile test machine were adopted to examine the surface structure, surface energy, impregnation effect and mechanical properties of CCF before and after surface treatments.The results indicated that treatment methods used all improved the performance of CCF, but CCF achieved optimum comprehensive performance after ultrasonichydrogen peroxide treatment

Development of Special Materials for PP-RCT Pipes

2017, 31 (09): 48-55; DOI: 10.19491/j.issn.1001-9278.2017.09.007

Abstract ( 417 )

Atactic copolypropylene (PP-RCT) was developed through the modification of crystallinity. A comparative investigation on structure and properties of PP-RCT and normal PPR resins was performed by gel permeation chromatography, differential scanning calorimetry, capillary rheometer, dynamic mechanical thermal analysis, polarized light microscopy, Fouriertransform infrared spectroscopy and conventional mechanical tests. Molecular structure, crystal morphology, mechanical properties of these resins were analyzed comprehensively. Resolutions for the development of PPRbased pipes special materials were proposed on the basis of production process, additives and other aspects.

Effect of Polypropylene with Different Molecular Weight on Properties of Isotactic Polybutene-/Polypropylene Blends

2017, 31 (09): 56-61; DOI: 10.19491/j.issn.1001-9278.2017.09.008

Abstract ( 405 )

Isotactic polybutene-1 (iPB-1)/polypropylene (PP) blends were prepared by melt blending, and effects of molecular weight and content of PP on their mechanical properties and crystallization behaviors were investigated.The results indicated that variation of molecular weight and content of PP almost did not influence crystallization temperature and relative crystallinity of iPB-1.On the other hand, incorporation of PP improved the flexible strength, flexible modulus and D-Shore hardness of the blends, but reduced their impact toughness.Moreover, there was no influence observed for the relative molecular weight of PP on tensile and flexible strength.With same PP content, the blends exhibited an increase in impact strength and D-Shore hardness with an increase of the relative molecular weight of PP.

Study on Properties of Poly(vinyl chloride)/Wheat Straw Composites

2017, 31 (09): 62-67; DOI: 10.19491/j.issn.1001-9278.2017.09.009

Abstract ( 422 )

Poly(vinyl chloride) (PVC)/wheat straw composites were prepared by a compression molding method, and effects of contents of wheat straw powders and different coupling agents on their mechanical properties and contact angle were investigated The results indicated that the composites achieved a maximum flexural strength when 40 wt % of straw powders was incorporated, and the straw powders were homogenously dispersed in the PVC matrix, leading to good properties of the composites The mechanical properties of the composites could be further improved through the modification of straw powders with coupling agents, and their flexural strength and Rockwell hardness achieved the optimum values with addition of 50 wt % straw powders In this case, the straw powders could be distributed in the matrix more homogenously due to the surface modification with coupling agents

Improvement of Flame Retardancy of Ethylene-vinyl Acetate Copolymer with Al(OH)3 and Mg(OH)2

2017, 31 (09): 68-72; DOI: 10.19491/j.issn.1001-9278.2017.09.010

Abstract ( 574 )

Effect of different mass ratios of aluminum hydroxide (ATH) and magnesium hydroxide (MH) on combustion characteristics of ethylenevinyl acetate copolymer (EVA)-based composites was investigated by limiting oxygen index (LOI), vertical burning test, thermogravimetric analysis, and cone calorimeter.The results demonstrated that the composites achieved the optimum flame retardancy with addition of ATH/MH mixture at the mass ratio of 2∶1, and their LOI values increased from 183 vol % to 344 vol %.Meanwhile, flame retardancy of the composites achieved a V-2 classification in UL-94 vertical burning test The cone experiments indicated that heat release rate and total heat release rate of the composites were reduced significantly

Preparation and Properties of ABS/Straw Fiber Composites

2017, 31 (09): 73-80; DOI: 10.19491/j.issn.1001-9278.2017.09.011

Abstract ( 437 )

Acrylonitrile-butadiene-styrene copolymer (ABS)/straw fiber composites were prepared by compression molding without using coupling agents, and effects of molding temperature and fiber content on their properties were investigated by universal mechanical testing machine, thermogravimetric analysis, scanning electron microscopy, gel permeation chromatography and rheometer.Experimental results suggested an optimum molding temperature and an optimum fiber ratio for the preparation of the composite as 170 ℃ and 100/30, respectively.However, seriously carbonized, and its surface silicon layer peeled off.In this case, the interface strength between the fiber and resin was reduced, but a compact network structure was formed by the fiber, which might enhance the absorption of impact energy.The relative molecular weight of ABS decreased with increasing the molding temperature, thus improving its impact strength.When the molding temperature and fiber content was set at 170~190 ℃ and 30~40 phr, respectively, the fiber straw achieved a good dispersion in the matrix was brilliant, thus leading to better mechanical properties for composites.

Grafting Polymerization of Styrene on Surface of Modified Graphene Oxide

2017, 31 (09): 81-85; DOI: 10.19491/j.issn.1001-9278.2017.09.012

Abstract ( 664 )

In this work, graphene oxide(GO) was surface modified by silane coupling agent γ-methacryloxy propyl trimethoxyl silane, and then styrene was grafted onto the surface of the surfacemodified GO for the purpose of flame retardancy. The resultant (GO-KH570)-g-polystyrene (PS) was characterized by Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis and scanning electron microscopy.The results indicated that (GO-KH570)-g-PS was successfully prepared.

Experimental Investigation on Bending Strength of Selective Laser Sintering Parts Based on Polystyrene and Modified Talc Powder Compounds

2017, 31 (09): 86-90; DOI: 10.19491/j.issn.1001-9278.2017.09.013

Abstract ( 351 )

Talc powders were surface modified with a titanate coupling agent, and polystyrene (PS)/surfacemodified talc powder compounds were prepared via mechanical mixing.Selective laser sintering parts based on these compounds were molded at a preheating temperature of 85 ℃ with 8layer grid support.Effect of layer thickness, scanning interval, laser power and scanning speed on bending strength of the sintering parts were studied by an orthogonal experiment.The results indicated that a chemical reaction occurred between functional groups of titanate coupling agent and active matters on surfaces of talcum powders, indicating that talcum powders achieved a successful surface modification.An investigation of process parameters indicated that effect of laser power on bending strength of the specimen was significant, but influence from layer thickness was little.Optimal process parameters for the sintering parts were a layer thickness of 018 mm, a scanning interval of 028 mm, a laser power of 27 W and a scanning speed of 1200 mm/s.With these process parameters, the sintering parts achieved bending strength of 1527 MPa.

Effect of Layer Thickness,Support Angle and Post-processing on Properties of SLA Parts

2017, 31 (09): 91-96; DOI: 10.19491/j.issn.1001-9278.2017.09.014

Abstract ( 507 )

This article reported an investigation on the accuracy and tensile property derived from the prototyping process and postprocessing technology for improvement of the accuracy and mechanical properties of SLA parts. VisiJet SL Black photosensitive resin was employed as a based material to prepare SLA parts.Effects of layer thickness and support angle on the size and surface accuracies of the parts were studied, and influence of postcuring time on their mechanical properties was evaluated.The results indicated that the parts achieved a higher size accuracy when the support angle was close to 45 °.A hump phenomenon was observed for the parts with a thick layer at a small support angle.Thicker layer resulted in a rougher surface for the parts The parts achieved a tensile strength around 9.33~22.84 MPa with a brittle fracture.When the postcuring time was set to 200 min, the parts obtained a best plasticity effect and thus gained the tensile strength of 20.24 MPa and elongation at break of 3.80 % as an optimum value However, the plasticity became poor for the parts at the postcuring time of 250 mins, although they achieved a maximum tensile strength of 22.84 MPa.

Heat Stabilization Effect of Aminouracils on Poly(vinyl chloride)—Progressive Change Law of Performance and Mechanism

2017, 31 (09): 97-101; DOI: 10.19491/j.issn.1001-9278.2017.09.015

Abstract ( 431 )

Effects of several 6-aminouracils on heat stability of PVC were investigated by an oven discoloration method.The results indicated that the heat stability of PVC was improved with an increase of electronwithdrawing capability of groups linked to the carbamido groups.Based on this progressive change law of heat stability as well as molecular structural characteristics of 6-aminouracils, it was predicted that 6-aminouracils could stabilize PVC by an electrophilic reaction with PVC through their 6-C atom as the electrophilic center.This means that the classical Frye and Horst’s theory are not suitable for the heat stabilization mechanism of 6-aminouracils, and therefore, the exact mechanisms for this new heat stabilizer should be clarified in further work.

An Experimental Investigation on Wall Slip of Different Polymer Melts

2017, 31 (09): 102-107; DOI: 10.19491/j.issn.1001-9278.2017.09.016

Abstract ( 310 )

Wall slip behavior of melts of polypropylene, high-density polyethylene polystyrene and poly(methyl methacrylate), was studied by a double capillary rheometer, and effects of shear stress and temperature on wall slip velocity (vs), and wall slip on flow of the melts were investigated. The results indicated that a stick-slip transition was observed for the four polymer melts vs increased as a power function of shear stress, and the critical shear stress for the onset of stickslip transition decreased with an increase of temperature.It was also observed that the effect of wall slip on melt filling behaviors was relative to the type of polymers, which became more significant with the decrease of channel diameters

Optimization of Parameters of Injection Molding Process Based on Taguchi and Synthetic Weighted Mark Methods

2017, 31 (09): 108-113; DOI: 10.19491/j.issn.1001-9278.2017.09.017

Abstract ( 271 )

Defects like warpage and volume shrinkage occurring in injection molding process of a casing were investigated by means of robust design, mean analysis and variable analysis methods.Based on the results obtained in this work, optimum combination of processing parameters as well as various influencing factors was obtained for minimizing warpage and volume shrinkage.To obtain a qualified product in both surface and size, such a combination included a melt temperature of 250 ℃, mold temperature of 250 ℃, a mold temperature of 250 ℃, injection time of 1.3 s, holding time of 25 s, cooling time of 19 s, and a holding pressure of 100 %.

Application of Photoinitiator and Multifunctional Monomers Containing Carbon Chains in PE-LLD

2017, 31 (09): 114-119; DOI: 10.19491/j.issn.1001-9278.2017.09.018

Abstract ( 777 )

A carbon-chain-containing photoinitiator (BPL) derived from benzophenone (BP) and a carbon-chain-containing multifunctional monomer (STAIC) derived from triallyl isocyanurate (TAIC) were used for photocrosslinking of linear lowdensity polyethylene (PE-LLD).Photoinitiation efficiency and thermal migration properties of BPL and STAIC in PE-LLD were investigated comparatively with BP and TAIC.The results indicated that combination of BPL and STAIC could initiate the photo-crosslinking of PE-LLD with high efficiency, and the optimum amounts of BPL and STAIC used for PE-LLD were 2.1 and 2.0 phr, respectively.Thermal migration test revealed that BPL and STAIC exhibited a much lower thermal migration rate in PELLD than BP and STAIC, respectively.After thermal migration, the photoinitiation efficiency of BPL and BP decreased by 3.6 % and 72.5 %, respectively.Furthermore, the enhanced crosslinking efficiency for STAIC in PE-LLD decreased by 46 %, whereas TAIC showed little influence on the photocrosslinking of PE-LLD.

Plasticizing Effect of HM-828 on Poly（vinyl chloride） Cable Materials

2017, 31 (09): 120-126; DOI: 10.19491/j.issn.1001-9278.2017.09.019

Abstract ( 474 )

In this paper, poly(vinyl chloride) (PVC) cable materials were prepared by melt blending, and plasticizing effect of a plant-based plasticizer, Diacetyl epoxidized vegetable-oil acids glyceride (HM-828), on PVC was investigated, and its plasticizing mechanisms were studied.The results indicated that HM-828 exhibited a high plasticizing efficiency for PVC, and it significantly reduced the glass transition temperature of PVC from 80 to-20 ℃ at a loading of 50 phr.Incorporation of 35~50 phr HM-828 into PVC could make mechanical properties, thermal stability and electrical resistance meet the reguirements of national standard of GB/T 8815—2008. The resulting PVC compounds also achieved a significant enhancement in solvent extraction resistance and precipitation resistance at both a high and low temperature.

Preparation of Activated Carbon Spheres and Their Application in Ammonium-polyphosphate Flame Retarded Epoxy Resin

2017, 31 (09): 127-132; DOI: 10.19491/j.issn.1001-9278.2017.09.020

Abstract ( 350 )

Colloidal carbon spheres were prepared by a hydrothermal method using glucose as a raw material, and then they were activation treated by phosphoric acid.The active carbon spheres (ACs) achieved the maximum specific surface area of 1354 m2/g.ACs were characterized by powder X-ray diffraction, Fourier-transform infrared spectroscopy and scanning electron microscopy.A flame retardant epoxy system was fabricated by incorporation of ACs along with ammonium polyphosphate (APP), and its synergistic flameretardant performance was investigated by limiting oxygen index, vertical burning experiment and micro calorimetry.The flameretardant mechanisms were studied by thermogravimetric analysis and scanning electron microscopy for the char residue.The results indicated that the flame retardant epoxy system achieved a V-0 classification in the UL 94 vertical burning test when 0.1 wt % of ACs and 2.9 wt % of APP were added.Moreover, its peak heat release rate decreased by 44.1 % in comparison with pure epoxy resin.

Flow Analysis of Improvement of Warpage in Magnetic Inserts of Plastic Parts

2017, 31 (09): 133-136; DOI: 10.19491/j.issn.1001-9278.2017.09.021

Abstract ( 421 )

Taking the injection-molding process of a cutting tool holder with magnetic inserts as a case study, this paper reported an investigation on the warpage defect occurring in injection-molded magnetic inserts by using acrylonitrile-butadiene-styrene copolymer (ABS) resin as a thermoplastic material and also proposed the resolution for this defect. A comparative analysis was conducted by means of Moldflow software for the influence factors derived from part structures, mould structures and process parameters.The results indicated that, through range analysis of process parameters and data analyses of product structures and gate locations, the warpage level could be improved by 15 % through optimizing the process parameters, improved by 53.7 % through optimizing the part structure, and improved by 76.5 % through optimizing the gate location.It was concluded that the optimization of gate location was the optimal method to diminish the warpage defect.

Design of Automatic Demoulding Mechanisms and Control Mechanism for Injection Molds of Rice Cookers

2017, 31 (09): 137-144; DOI: 10.19491/j.issn.1001-9278.2017.09.022

Abstract ( 376 )

Structural features of injection moulds of rice cookers were investigated intensively, and then sixty sorts of special demoulding mechanisms were designed through classifying design methods aiming to the characteristics of demoulding mechanisms.A front mould ejector plate mechanism was designed on the basis of front cavity demoulding requirements for deep cavities and deep columns.Moreover, a two-stage compound ejection mechanism driven by two guide cylinders was designed by combination of simultaneous demoulding on two directions and side features.In addition, three types of side core pulling mechanisms driven by T groove lock blocks were designed according to the location of three side holes on the front and back mould.The final ejection of products was pushed out jointly by the slider-ejector rod and ejector.According to the requirement of automatic production for the mould, a six-plate bearing frame and relevant templating openingclosing logic control mechanism were designed.Experimental results indicated that design of these mechanisms and die structures were reasonable, and therefore, the automatic injection-molding production was well carried out.