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2015, Volume 29 Issue 04 Publication date: 26 April 2015 Previous Issue Next Issue

Recent Research Status of Flame Retardants in Polystyrene Foams

2015, 29 (04): 1-8 ; DOI: 10.19491/j.issn.1001-9278.2015.04.001

Abstract ( 584 )

In this article, the recent research status of fireretardance of polystyrene by halogencontaining and nonhalogen flame retardants was reviewed. The advances and shortcomings of bromostyrene, decabromodiphenyl, brominated epoxy, metal hydroxide, and clay based flame retardants and intumescent flame retardants were introduced. Finally, efficient and environmentally friendly nonhalogen flame retardants were emphasized.

Influencing Factors of Thermal Stability Effect of Hydrotalcite Compound Stabilizers and Their Application Ways as Thermal Stabilizers

2015, 29 (04): 9-13 ; DOI: 10.19491/j.issn.1001-9278.2015.04.002

Abstract ( 433 )

This paper briefly reviewed the thermal stability mechanism of hydrotalcites, and the factors influencing the thermal stability of hydrotalcites, including synthesis conditions, anion intercalation, cationic species as well as modification. The application of hydrotalcites as a thermal stabilizer in PVC was introduced.

Research Progress of Flame Retardancy Modification of Aromatic Polyimide

2015, 29 (04): 14-18 ; DOI: 10.19491/j.issn.1001-9278.2015.04.003

Abstract ( 486 )

The modification of aromatic polyimide such as blending and copolycondensation was introduced in this article. In terms of introducing different groups, copolymerization modification can be classified into polyamideimide, polyester imide, nitrogencontaining heterocyclic and so on. Structural modification includes the introduction of hybridized element, functional perdant group, scrolt structure and noncoplanar structure into main chain.The application of polyimide in the field of flame retardant was also discussed.

Preparation and Mechanical Properties of PA6/Glass Fiber/Slag Powder Composites

2015, 29 (04): 19-23 ; DOI: 10.19491/j.issn.1001-9278.2015.04.004

Abstract ( 481 )

With slag powder and glass fibers as fillers in PA6 matrix, a ternary composite was prepared. Scanning electron microscope (SEM) was utilized to observe its fracture morphology. The effect of mass ratio of slag powder/glass fiber ratio and their size on the tensile strength, impact toughness of the composites was studied. It showed that when the slag powder/glass fiber ratio was 1:3, the amount of the fillers was 30 %, the average particle size was 7 μm, the tensile strength reached 96.8 MPa. When the average particle size of slag powder was 15 microns, the ternary composite had an impact toughness of 8.31 kJ/m2, which was 132.4% that of neat PA6.

Influence of Chain Extentions on Cell Structures of Extrusion Foaming of Poly(lactic acid)

2015, 29 (04): 24-29 ; DOI: 10.19491/j.issn.1001-9278.2015.04.005

Abstract ( 516 )

The neat PLA was modified by chain extension and the influence of the chain extender on the rheological properties was investigated. Three chemical agents, foaming agent A (Masterbatch), foaming agent B（AC+NaHCO3）and foaming agent C (modified AC), were used to investigate the foamablibity of PLA. The density and cell morphology of extrusion foamed PLA were studied. It showed that the foamability of PLA was improved by adding the chain extender, which increased viscosity and decreased the melt flow rate. The foamability was best when the chain extender content was 0.8. The size, shape, density and distribution of the cells of the foamed PLAs were examined. The best foamed PLA was found with foaming agent C, with the density, cell diameter, and cell density being 0.6 g·cm-3, 57 μm, and 7.37×10^6 per·cm-3,respectively.

Properties of Perfluoropolyether Modified Ultra-high Molecular Weight Polyethylene Composites

2015, 29 (04): 30-35 ; DOI: 10.19491/j.issn.1001-9278.2015.04.006

Abstract ( 640 )

Ultra high molecular weight polyethylene (PE-UHMW) was modified with perfluoropolyether (PFPE) and the effect of PFPE content on the mechanic properties, friction and wear properties of PEUHMW was studied. The thermal properties of the composites were analyzed by thermo gravimetric analyzer (TG) and differential scanning calorimeter (DSC). At the same time, the worn surfaces of the composites were observed on a scanning electron microscope. It was found that when the content of PFPE was fixed at 3 %, its friction coefficient and bulk worn loss decreased by 20.8 and 59.4 %, respectively. PFPE had little effect on the mechanical and thermal properties of the composites. The wear mechanisms of unmodified PE-UHMW were adhesive wear and plastic deformation, those of modified PE-UHMW were fatigue and plastic deformation.

Morphology and Foaming Behavior of PS/PLA Blends

2015, 29 (04): 36-41; DOI: 10.19491/j.issn.1001-9278.2015.04.007

Abstract ( 124 )

Effect of Water Absorption on Mold Resistance of PE-HD/Bamboo-flour Composites

2015, 29 (04): 42-47 ; DOI: 10.19491/j.issn.1001-9278.2015.04.008

Abstract ( 476 )

This paper mainly researched the effect of water absorption on mold resistance of PE-HD/bambooflour composites. The water absorption, surface morphology and mold ratings of PE-HD/bambooflour composites after mold exposure was investigated. It was found that: water absorption increased with increasing watersoaking time and bamboo content. No obvious correlation and significant difference between water absorption and mold resistance were observed between the mold resistance of composites after 0, 2, 4, 8, 11 d water soaking. In contrast, the bamboo content and the addition of ZnB have a great effect on mold resistance. Composites containing higher bamboo content were more susceptible to mold fungi, and the addition of ZnB remarkably improved the mold resistance of WPC by decreaseing mold ratings from 3~4 to 0~1.

Compatibility of PHBH/PLA Blends

2015, 29 (04): 48-53 ; DOI: 10.19491/j.issn.1001-9278.2015.04.009

Abstract ( 613 )

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate）（PHBH)/poly(lactic acid）（PLA) blends were prepared by melt blending using a twin screw extruder. The mechanical properties, thermal behavior, and microstructure of the PHBH/PLA composites were investigated. Compared with neat PHBH, the elongation at break and impact strength of PHBH/PLA (80/20) were increased by 38 % and 15.7%, respectively. DSC indicated that the difference between glass transition temperatures of PHBH and PLA was decreased slightly, indicating the improvement of compatibility.

Preparation and Properties of Novel Thermally Conductive Epoxy/Carbon Nanotubes Composites

2015, 29 (04): 54-57 ; DOI: 10.19491/j.issn.1001-9278.2015.04.010

Abstract ( 609 )

Crude CNTs were first treated with an acid solution and then subjected to air oxidation, particles of metal catalyst and amorphous carbons on the surface were effectively removed and the CNTs were purified. The purified CNTs were used in EP/CNTs thermal conductive composites. The thermal conductivity, impact strength, flexural strength of EP/CNTs composites were investigated. When the content of purified CNTs was 1.5 wt %, the impact strength, flexural strength, and thermal conductivity were 24.95 kJ/m2, 127.2 MPa, and 1.237 W/（m·℃）, respectively.

Preparation and Properties of POM/Elastomer/Nano-CaCO3 Composites

2015, 29 (04): 58-63 ; DOI: 10.19491/j.issn.1001-9278.2015.04.011

Abstract ( 511 )

Polyoxymethylene (POM)/thermoplastic polyurethane elastomer (TPU)/nano calcium carbonate (nano-CaCO3) composite materials were prepared by melt compounding with four different mixing sequences. Through mechanical property testing, polarizing microscope(PLM), differential scanning calorimetry(DSC), melt flow rate, and scanning electron microscope (SEM), the effects of different dosages of nano-CaCO3 and blending methods on the mechanical properties and microstructure morphology of the composites were investigated. Premixing TPU with 4 % nano-CaCO3，the composites exhibited excellent impact resistance. The measured notched Izod impact strength was near 12.5 kJ/m2.

Effect of HCFC-141b on Structure and Properties of Polyurethane-imide Foams

2015, 29 (04): 64-69 ; DOI: 10.19491/j.issn.1001-9278.2015.04.012

Abstract ( 576 )

Polyurethaneimide (PUI) foam was prepared from polyphenyl polymethylene polyisocyanates, pyromellitic dianhydride, and castor oil with prepolymer method using HCFC-141b. The effect of amount of HCFC-141b on the chemical structure, cell structure, open cell content, density, volume expansion rate，mechanical properties, and thermal behavior was analyzed. It showed that, HCFC-141b did not change the chemical structure and thermal behavior of the foam. With the increase of HCFC-141b from 0 % to 10 %, average cellular diameter, open cell content, and volume expansion rate increased, while the density and compressive strength decreased. Thus the structure and properties of the PUI foam could be adjusted through changing the amount of HCFC-141b.

Study on the Energy Consumption in Filling Stage Based on the Software of Moldflow MPI

2015, 29 (04): 70-74 ; DOI: 10.19491/j.issn.1001-9278.2015.04.013

Abstract ( 453 )

This paper established a relationship among energy consumption and four factors, width of the gate, wall thickness of the products, injection velocity, and diameter of the products, using Moldflow, orthogonal test, and multivariate fitting. The accuracy of the formula for energy consumption was higher than 90 %.

Numerical Simulation and Experimental Analysis of Mixed Flow of Materials with High Content of Aluminum Powder

2015, 29 (04): 75-81 ; DOI: 10.19491/j.issn.1001-9278.2015.04.014

Abstract ( 379 )

Three dimensional mixing flow fields of a composite melt around the metering zone (the length was 440 mm) of 4 screw assemblies were simulated by utilizing polymer flow package Polyflow. The composite was highly filled with aluminum powder. Based on the analysis of the flow field，especially the shear rate, shear stress, and axial velocity distribution, general distribution characteristics and mixing capability were studied. The performance of screw elements was compared. The results of holistic simulation, which were verified with experiments, showed that the screw configuration with negative elements and kneading disks had higher dispersive and distributive mixing capability for aluminum powder filled materials.

Preparation and Properties of Strengthened and Toughened PBT/PC Blends

2015, 29 (04): 82-87 ; DOI: 10.19491/j.issn.1001-9278.2015.04.015

Abstract ( 625 )

Glycidyl methacylate functionalized acrylonitrilebutadienestyrene copolymer\[ABS-g-(GMA-co-St), AGS] was prepared by melting grafting and was used to modify poly(butylene terephthalate)/polycarbonate (PBT/PC=80/20) blends. SEM showed that the interfacial adhesion between PBT and PC was improved with increasing AGS content. The addition of 10 wt % of AGS caused 49.8 % and 17.4 % increments in notched impact strength and tensile strength of the PBT/PC blends, respectively, the interfacial bonding strength and miscibility of the blends were also enhanced. In addition, DSC test indicated that the incorporation of AGS increased the crystallization peak temperature and spherulite growth rate of the blends.

Optimization of Injection Processing Parameters Based on Improved Efficient Global Optimization Algorithm

2015, 29 (04): 88-92 ; DOI: 10.19491/j.issn.1001-9278.2015.04.016

Abstract ( 450 )

IMEGO algorithm proposed to conquer premature convergence might occur in EGO algorithm when the objective function varied in a large range in this study. The optimal solution of the kriging model for each iteration was preferred and stopping criteria on expected improvement was added in the IMEGO algorithm. The IEGO was compared with traditional EGO through a onevariable test function and three twovariables test functions, it was then shown that the improved EGO could effectively search the global optimum. The IMEGO was used to optimize injection molding process parameters for covers of liquid crystal display parts and the results showed that it had a good application in engineering.

Influence of β-nucleating Agent Coutents and Annealing Treatment on Mechanical Properties of Modified Polypropylene

2015, 29 (04): 93-97 ; DOI: 10.19491/j.issn.1001-9278.2015.04.017

Abstract ( 456 )

Polypropylene containing a β nucleating agent was prepared by melt extrusion method. The effects of the content of nucleating agent and annealing treatment on the mechanical properties of the modified polypropylene (β-PP) were studied. The microstructure of β-PP was characterized by wideangle X-ray diffraction (WAXD) and scanning electron microscopy (SEM). It showed that the mechanical properties of β-PP achieved the maximum value when the content of β nucleating agent was 0.05 %, and the modification effect could be further improved by annealing treatment at 110 ℃ for 1 h. Micromorphological research indicated that a suitable content of nucleating agent and annealing treatment were beneficial for β crystal formation and the integrity of crystals. The fractured surface of annealing treated βPP exhibited obvious plastic deformation.

Preparation and Application of Sec-butyl Triazine and Three Phenyl Hypophosphorous Acid Compound

2015, 29 (04): 98-101 ; DOI: 10.19491/j.issn.1001-9278.2015.04.018

Abstract ( 448 )

A new phosphorus and nitrogen synergistic flame retardant, 2,4,6three(Osecbutylphenyl phosphinic acyl)1,3,5triazine, was prepared from tricyanogen chloride and Phenyl hypophoaphoeous acid two secbutyl. Each reaction condition was optimized. The optimal reaction condition was as follow: n(tricyanogen chloride):n(phenyl hypophoaphoeous acid dibutyl) was 1：3.2, reaction time was 5 h at 100 ℃ with fractionating the 2chlorobutane generated by the reaction, the target product was obtained after distilling organic solvents and recrystallization with a yield of 89.4 %. The structure of the product was characterized by FTIR, 1H-NMR and the flame retardant properties of the product were measured by limited oxygen index technique. The highest limited oxygen index of the product flame retarded PBT,the product and MCA flame retarded PBT, the product and MPP flame retarded PBT were 21 %, 30 %, 26 %, respectively.

Study on Preparation of Waterproof Coatings Graftmodified with Waste Polystyrene Particles

2015, 29 (04): 102-106 ; DOI: 10.19491/j.issn.1001-9278.2015.04.019

Abstract ( 520 )

An emulsion type waterproof coating was prepared with acrylic acid and butyl acrylate grafted waste PS foam as the main raw material. The effects of initiator loading, monomer ratio, reaction temperature, and reaction time on the grafting rate of PS were studied. It was found the optimal recipe was: PS 30 g, solvent 60 mL, initiator 2.2 g, monomer 20 g, filler 10 wt %, plasticizer 4 wt %, both based on the weight of grafted PS, the reaction temperature 85 ℃, the reaction time 2.5 h. The waterproof time was 25 h; the time of torlerance of salinity was 27 h, the dry time was 18 min, and the impact strength was 50 kg·cm.

Design of Injection Molds for Curved Tail Joints

2015, 29 (04): 107-110 ; DOI: 10.19491/j.issn.1001-9278.2015.04.020

Abstract ( 569 )

According to the special structure of the curved tail joint parts, an injection mold was designed. The outer shape of the plastic part was formed by two fitting side sliding blocks, and the inner shape formed by combinedtype dynamic and static inserts, and the plastic parts were pushed out by a pushing board. During mold opening, the side sliding blocks parting was realized by the inclined pillars, simultaneously the dynamic and static inserts were drawn out in the direction of mould opening. When the mould was closed, both sides of the slide dies were locked by a pair of special technical keys and locking wedge, and the burrs were effectively prevented, the quality of product was guaranteed. The drive system of side parting and corepulling mechanism simplified the mould structure, making the operation of the mold reliable.

Characteristics of Double-toggle Clamping Units with Diagonal-five Points of Plastics Injection Machines

2015, 29 (04): 111-119 ; DOI: 10.19491/j.issn.1001-9278.2015.04.021

Abstract ( 510 )

An elastic dynamic model for doubletoggle clamping unit on a highspeed precision plastics molding machine was derived, by modality analysis principium, which was used in detailed study of KED/KES. The vibration acceleration signal of the toggle was measured. Through LMS，the vibration displacement was obtained by eliminating the trend item, smoothing, and secondary frequent domain integral, and compared it with theoretical value. The model was proved to be reasonable, which provided a basis for the design of toggle mechanisms.