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2015, Volume 29 Issue 06 Publication date: 26 June 2015 Previous Issue Next Issue

Research Progresses in β Nucleating Agents for Polypropylene

2015, 29 (06): 1-6; DOI: 10.19491/j.issn.1001-9278.2015.06.001

Abstract ( 771 )

In this review, the characteristics of βcrystalline phases of polypropylene（PP） was introduced, and the type of β nucleating agents and their applications for PP were summarized. Moreover, the research progress about β nucleation in PP was also discussed.

Research Advance in Halogen-free Frame Retardant Polypropylene

2015, 29 (06): 7-12; DOI: 10.19491/j.issn.1001-9278.2015.06.002

Abstract ( 479 )

The effects of several halogenfree flame retardants，including hydroxide，intumescent，phosphorsbased，and siliconbased，on polypropylene（PP）were reviewed. It was recognized that synergistic effects could overcome the shortcoming of a single retardant. It was pointed out that developing new flameretarding systems and improving the compatibility between flame retardants and the matrix will be hot topics in the future.

Research Progress in Biodegradable Poly (lactic acid) Foams

2015, 29 (06): 13-23; DOI: 10.19491/j.issn.1001-9278.2015.06.003

Abstract ( 682 )

The wide array of applications for PLA foams, such as packaging, automobiles, and tissue engineering, were introduced. And, various PLA foaming technologies, such as solidstate foaming, extrusion foaming, injection foaming, and other foaming methods, as well as their foaming mechanism, were also listed. Some advanced and effective modification methods, including chain branching of PLA molecular, blending with other polymers, and filling with micro-/nanosize particles, were dealt with. And, the cellular structures induced by the modifications of PLA were also introduced.

Study on Processing Conditions and Properties of Long Jute Fibers Reinforced High Density Polyethylene Composites Prepared by Melt Impregnation Process

2015, 29 (06): 24-27; DOI: 10.19491/j.issn.1001-9278.2015.06.004

Abstract ( 442 )

A device for thermoplastics melt impregnation of nature fibers was developed. Long jute fibers reinforced high density polyethylene was prepared by the mold impregnation process. Effects of fiber content and impregnation temperature on mechanical properties and microstructure of the composite were studied. When the loading of jute fibers was 45 % and impregnation temperature was 210 ℃, the tensile strength was increased by 49.1 % and the flexural strength was increased by 137 %.

ffect of a Coupling Agent on Mechanical Properties and Thermal Stability of PBS/Calcium Carbonate Whisker Composites

2015, 29 (06): 28-33; DOI: 10.19491/j.issn.1001-9278.2015.06.005

Abstract ( 550 )

Calcium carbonate whisker (CCW) was surface modified by 3aminopropyltriethyloxy silane (KH550) and blended with poly(butylene succinate) (PBS) and subsequently granulated via melt extrusion. When the loading of CCW was below 5 %, the tensile, bending, and impact strengths of the resultant PBS/CCW composites increased 1 %~3.9 %, 10 %~16 %, and 1 %~4.5 %, respectively, based on neat PBS. When the loading of CCW was larger than 5 % and 10 %, the tensile strength and impact strength began to reduce, respectively. However, the bending strength kept increasing with CCW loading. Surface modification of CCW by KH550 improved the interfacial adhesion of the PBS/CCW composites. CCW acted as a nucleating agent, the crystallization temperature and crystallinity of PBS increased 0.2 ℃ and 0.2 %, respectively.

Non-isothermal Crystallization Kinetics of PERT

2015, 29 (06): 34-38; DOI: 10.19491/j.issn.1001-9278.2015.06.006

Abstract ( 415 )

The effect of comonomer content and branched chain distribution on nonisothermal crystallization kinetics of polyethylene octene copolymer was studied by differential scanning calorimeter. It showed that the half crystallization time t1/2 and the cooling rate increased, but the crystallization rate constant Zc reduced with increasing comonomer content and increasing uniformity of branched chain distribution. The crystal growth dimension n changed between 2~3. The ratio of Avrami index n and Ozawa index m kept stable with increasing crystallinity.

Study of EG/DMMP Flame Retardant Polyurethane-imide Foam

2015, 29 (06): 39-43; DOI: 10.19491/j.issn.1001-9278.2015.06.007

Abstract ( 664 )

Polyurethaneimide（PUI）was filled with expandable graphite (EG) and dimethyl methylphosphonate (DMMP) forming flame retarded plastics, whose flame retardant properties, morphology of surface carbon layer, and mechanical properties were studied. Compared with systems containing EG alone, the introduction of DMMP generated more continuous and dense carbon layer after burning, and thus increased the limiting oxygen index from 18.6 % to 33.4 %. The combination of EG and DMMP had less effect on the compressive property of PUI than that when EG was used alone.

Influence of Annealing on Crystallization and Heat Resistance Properties of Poly(lactic acid)

2015, 29 (06): 44-48; DOI: 10.19491/j.issn.1001-9278.2015.06.008

Abstract ( 779 )

Activation sepiolite (ADI-S) was introduced into poly(lactic acid) (PLA) as a nucleating agent. The influence of annealing on the crystallization and thermal behaviors of PLA was studied by differential scanning calorimetry, wideangle X-ray diffraction, polarized optical microscope, and Vicat softening point tester. It showed that the nucleating agent increased the degree of crystallization and heat resistance in short annealing time. The crystallinity of PLA/ADI-S was 53.3 % and Vicat softening temperature was 83.3 ℃ while annealed at 90 ℃ for 10 minutes.

Study of the Performance of PET/Nano-MgO Composite

2015, 29 (06): 49-52; DOI: 10.19491/j.issn.1001-9278.2015.06.009

Abstract ( 614 )

Composites of polyethylene glycol terephthalate (PET) and nano magnesium oxide（nano-MgO）were prepared by melt blending. The ultravioletshielding property of the composites was tested by ultravioletvisible absorption spectra. It is shown that when the content of nanoMgO was 1 %，the notch impact strength of the composite was 15 % higher than neat PET. When the nanoMgO content was 2 %, the tensile strength of the composite was 8 % higher than neat PET. SEM showed that the nanoMgO was welldispersed in the composites. When the content of nanoMgO was 2 %，the half width of the crystallization peak of the composite was 7.7 ℃, which was 15 % lower than neat PET. The import of nanoMgO could improve the melting point of PET. When the content of nanoMgO was 2 %，the half width of the melting point of the composite was 252.4 ℃, which was 4.1 ℃ higher than neat PET. When the content of nanoMgO was 3 %，the cutoff wavelength of ultravioletshielding property of the composite was 300 nm, which was 11 % higher than neat PET.

Properties of Epoxy/BMI Blends Modified with Organosilicone

2015, 29 (06): 53-58; DOI: 10.19491/j.issn.1001-9278.2015.06.010

Abstract ( 487 )

A modified resin system of E-51/BMI/SIDA was prepared by expanding chain reaction of bis (4-aminophenoxy) dimethylsilane (SIDA) and BMI. When the content of SIDA was 20 wt %, the impact strength and flexural strength of E-51/BMI/SIDA was 38.52 kJ/m2 and 120.54 MPa, respectively. The 5 % weight loss temperature of E-51/BMI/SIDA was 336.8 ℃, and the char yield of the blends was 55.4 % at 600 ℃, the water absorption performance of E-51/BMI/SIDA was 0.78 % at 8 days.

Morphologies of PP/POE/Nano-CaCO₃ Ternary Composites Prepared by Supercritical CO₂-assisted Extrusion#br#

2015, 29 (06): 59-65; DOI: 10.19491/j.issn.1001-9278.2015.06.011

Abstract ( 119 )

Electrospinned Porous Ultrafine Polyethersulfone Fibers and Their Application in Adsorpion for Bisphenol A

2015, 29 (06): 66-71; DOI: 10.19491/j.issn.1001-9278.2015.06.012

Abstract ( 536 )

In this paper, porous ultrafine polyethersulfone (PES) fiber were prepared by combining electrospinning technique with immersing gelation methods. When polyethylene glycol (PEG) was used as a porogen, the fiber had homogeneous distributed small holes; when poly(vinyl alcohol) (PVA) was a porogen, large and orientated holes were formed. Collecting methods had significant influence on the morphology of the porous fiber. The fiber was porous when collected in air and hollow when collected in water. The porous ultrafine fibers were employed to adsorb bisphenol A from aqueous solution. The mechanism of adsorption was investigated. Results showed that the adsorption kinetic data were fitted well with pseudosecondorder kinetic model and that the Freundlish isotherm model was suitable to describe the isotherm adsorption.

Numerical Simulation and Optimum Design of Spirally Grooved Runner Rollers

2015, 29 (06): 72-77; DOI: 10.19491/j.issn.1001-9278.2015.06.013

Abstract ( 602 )

In this paper, the spiral groove roller model was simplified reasonably. The temperature field of the runner roller was obtained by Fluent, and other parameters such as the rate of fluid in runner, the fluid temperature field, the surface temperature field of the roller were obtained. The reasons for the uneven distribution of the surface temperature were found by analyzing the simulation results. On this basis, in order to improve the uniformity of temperature distribution on the roller surface, the structure of the runner was optimized repeatedly. The surface temperature uniformity at the end region of the roller was improved obviously and the effective interaction length of the roller was prolonged about 50 mm.

Influence of Stretching Ratio on Properties of BOPP Films

2015, 29 (06): 78-81; DOI: 10.19491/j.issn.1001-9278.2015.06.014

Abstract ( 704 )

In this paper, a bi-axially stretching was applied on a commercial polypropylene film and relationship between the stretching ratio and the properties was established. It showed that with increasing MD stretching, the film Haze was declining and the film gloss was improved. While, with increasing TD stretching, the film TD tensile strength increased linearly. The TD stretching ratio remarkably affected the properties of BOPP film.

Reverse Analysis of Mechanical Properties of Self-healing Microcapsule Shell Materials

2015, 29 (06): 82-86; DOI: 10.19491/j.issn.1001-9278.2015.06.015

Abstract ( 424 )

The relationship between microcapsule structure stiffness coefficient and Young's modulus of microcapsule shells was obtained in this paper by the combination of nanoindentation test and finite element analysis. According to the results of finite element analysis, the Young's modulus of microcapsule shell was 1.97 GPa and the failure stress was 52.42 MPa. The P-h curve obtained by finite element analysis was consistent with the experiment curve, which further proved the reliability of the simulate results.

Synthesis of ACR Impact Modifier and Its Application in Poly(lactic acid)

2015, 29 (06): 87-92; DOI: 10.19491/j.issn.1001-9278.2015.06.016

Abstract ( 538 )

An impact modifier was synthesized with a mixture of moderately crosslinked poly silicone rubber and butylacrylate copolymer as the core and methyl methacrylate and glycidyl methacrylate copolymer as the shell. The composition and structure were characterized with infrared spectroscopy and transmission electron microscope. The impact modifier was applied in the poly(actic acid)（PLA）with a loading of 10 % and an average particle size of 280 nm. The notched impact strength of PLA reached 39.6 kJ/m2, the haze was below 20 %, melting time was reduced by 9 min, the balance torque increased by 3.3 N·m, and maximum torque increased by 2 N·m.

Synthesis of Tetradecanoic Acid Intercalated Rare-earth Hydrotalcite-like and Its Thermal Stabilization on PVC

2015, 29 (06): 93-97; DOI: 10.19491/j.issn.1001-9278.2015.06.017

Abstract ( 510 )

Six kinds of tetradecanoic acid intercalated rareearth (La/Ce/Pr/Nd/Sm/Eu) hydrotalcitelikes were synthesized by coprecipitation method. The products were characterized by Xray powder diffraction (XRD), infrared spectrum (FTIR) and themogravimetric analysis (TG). It showed that the products imparted good thermal stability to PVC. The La doped hydrotalcitelikes was the best and exhibited obvious synergistic effect with zinc stearate and pentaerythritol. The static and dynamic thermal stability time reached 110 and 35 min, respectively. The plasticizing torque and balancing torque were 51 and 30 N·m , respectively. UV showed that the product could inhibit the formation of the conjugated polyene with longer chain length and slow down the sample color before and after being compounded, especially after being compound.

Simulation for Pipe Molding Devices with Two Dies Based on Polyflow

2015, 29 (06): 98-101; DOI: 10.19491/j.issn.1001-9278.2015.06.018

Abstract ( 447 )

Features and basic analysis process have been introduced. Taking random copolymerization polypropylene (PP-R) pipe extrusion as an example, the process of flowing field analysis and inverse designing for a die was introduced. By using Polyflow software the complex flow of the melt could be predicted.

Thermal Response Analysis of Conformal Cooling Structure of Molding In Products Formation in Injection Molding

2015, 29 (06): 102-106; DOI: 10.19491/j.issn.1001-9278.2015.06.019

Abstract ( 469 )

The thermal response of the conformal cooling structure of a mold was studied. The traditional mold cooling structure was linear, the cooling effect was not good. We designed a new cooling structure named conformal cooling. The transient thermal responses of the two structures were compared via the analysis of ANSYS program, the cooling efficiency and cavity temperature field distribution of the two schemes were obtained based on Moldflow and CFD software, and the potential flaw was examined. It turned out that the cooling effects of conformal cooling was better than traditional one, with cooling time reduced by 50 %, volume shrinkage rate reduced by 15 %. Besides, it could adjust the mold temperature and get into the stable working condition more quickly.

Design of a Large Bump Flattening Machine for Polymer Powder Used in Compression Molding

2015, 29 (06): 107-112; DOI: 10.19491/j.issn.1001-9278.2015.06.020

Abstract ( 429 )

The accurate controlling of the scraper in large bump flattening machine for polymer powder was realized by the synchromechanism of turbineworm. The deformation of the main girder structure was avoided through designing the welding sequence reasonably. Then the precision control mechanism was made. Finite element analysis (FEA) was utilized to optimize the structure of the prototype. The optimized structure was lighter, and showed good prospect in industry application.