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2015, Volume 29 Issue 12 Publication date: 26 December 2015 Previous Issue Next Issue

Research Progress in Screw Extrusion Technology of Explosives

2015, 29 (12): 1-7 ; DOI: 10.19491/j.issn.1001-9278.2015.12.001

Abstract ( 1268 )

The screw extrusion technology of composite explosives was reviewed from three aspects as below: security analysis of screw extrusion technology, the material type that could be processed by screw extrusion technology and the improvement of the material properties through improving screw extrusion technology. The problems that higher internal friction in single screw extrusion and lower pressure of twinscrew extrusion were indicated and the adaptability of conical twinscrew extruders was proposed.

Research Progress in Functional Polyethylene for Rotational Molding

2015, 29 (12): 8-13 ; DOI: 10.19491/j.issn.1001-9278.2015.12.002

Abstract ( 996 )

Several special polyethylene resins including superior impact and thermal resistance polyethylene, high adhesive polyethylene for inner liner of chemical containers, lightweight foamable polyethylene, and functional polyethylene for rotational molding were introduced, and their characteristics and properties were reviewed. Prospect of their development was also given in the end of this paper.

Influence of TPP and MBS on Properties of PC/ABS Blends

2015, 29 (12): 14-17 ; DOI: 10.19491/j.issn.1001-9278.2015.12.003

Abstract ( 1130 )

The effect of triphenyl phosphate (TPP) and methyl methacrylatebutadienestyrene (MBS) on the properties of polycarbonate/acrylonitrilebutadienestyrene (PC/ABS) blend was investigated. It showed that when 16.7 wt % TPP was introduced, PC/ABS blend could achieve a V-0 rating in UL 94 tests, limiting oxygen index was also improved remarkably. When MBS was introduced as a compatibilizer, the limiting oxygen index was further increased. TPP retarded the degradation of alloys, improved the thermal stability, and increased the char residue in nitrogen atmosphere, while MBS promoted the degradation of alloys.

Preparation and Performance of Poly(N-isopropylacrylamide)/Clay Nanocomposite Self-healing Hydrogel

2015, 29 (12): 18-22 ; DOI: 10.19491/j.issn.1001-9278.2015.12.004

Abstract ( 953 )

A new kind of poly (N-isopropylacrylamide)/clay nanocomposite hydrogel (PNIPA/Clay) was prepared using inorganic clay as a crosslinker by insitu polymerization method. The effect of the ratio of monomer, clay and dispersant on the performance of hydrogels was investigated. Experimental results indicated that when the ratio of monomer/clay was 1.5~2.0 and monomer/dispersant was 1：10, the hydrogel had excellent gelling performance. The swelling ratio decreased with increasing clay contents. The maximum swelling ratio was 12.8 g/g. The hydrogel displayed excellent selfhealing performance and the cut surfaces of hydrogels could autonomically fusion at room temperature within 24 h. The selfhealing efficient of 43.0 % was obtained.

Effect of Compatibilizers on Properties of PE-HD/Recycled Paper/Plastic/Aluminum Composites

2015, 29 (12): 23-28 ; DOI: 10.19491/j.issn.1001-9278.2015.12.005

Abstract ( 879 )

PE-g-MAH, POE-g-MAH, and POE-g-GMA were used as a compatibilizer separately in composites of PE-HD and recycled powder of paper/plastic/aluminum (r-PPA). The effect of the compatibilizers was characterized using mechanical property testing, rheological property, water absorption, and scanning electron microscope (SEM). It showed that POE-g-GMA had the greatest influence on the mechanical properties of composites. When 6 phr POE-g-GMA was introduced, the tensile strength was increased by 32.9 %. And the composite exhibited ductile fracture with fibrils observed on the brittle fracture surface. Furthermore, the system gave rise to a quasi solidliquid phase transition. PE-g-MAH had the greatest influence on the water adsorption of the composites. With 10 phr PE-g-MAH, the water adsorption was reduced by 54.2 %.

Flame Retardancy and Mechanical Properties of EPS Foams Coated with MG-MUF

2015, 29 (12): 29-33 ; DOI: 10.19491/j.issn.1001-9278.2015.12.006

Abstract ( 1016 )

Modified graphite (MG) was prepared by Hummers method, which was introduced into PVA modified ureaformaldehyde resin (MUF) by insitu intercalation polymerization. The obtained compound resin MGMUF was used as coating of preexpanded polystyrene (EPS) beads. The coated beads were thermally pressed into templates, whose flame retardantcy, thermal insulation properties, and mechanical strength were characterized. When MG in MGMUF was 20 % and the coat ratio was 3：1, the limiting oxygen index of retardant templates reached 30.5 %, the horizontal burning grade of the template was HF-1.

Modification of Poly(3-hydroxybutyrate)/Lignophenol Composite Films by Polypropylene Fiber

2015, 29 (12): 34-38 ; DOI: 10.19491/j.issn.1001-9278.2015.12.007

Abstract ( 1370 )

PHB/PP and PHB/PP/lignophenol composite films were prepared by blend casting. The effect of polypropylene fiber and lignophenol on the mechanical and thermal properties was studied. When polypropylene fiber content was 8 % and lignophenol content was 3 %, the overall property of PHB/PP/lignophenol composite film was the optimal. The polypropylene fiber and lignophenol were beneficial to tensile strength and thermal properties, respectively.

Effects of the Structure of PLA-b-PMMA on Morphologies and Properties of PC/PLA Blends

2015, 29 (12): 39-45 ; DOI: 10.19491/j.issn.1001-9278.2015.12.008

Abstract ( 951 )

Block copolymers of lactic acid and methyl methacrylate (PLA-b-PMMA) with different block lengths were synthesized, which were used as a macromolecular compatibilizer to improve the compatibility of polycarbonate (PC) and poly(lactic acid) (PLA). Fourier transform infrared spectrometer (FTIR) and nuclear magnetic resonance spectroscopy (NMR) were used to characterize the structure of PLAbPMMA. Differential scanning calorimeter (DSC)，scanning electron microscopy (SEM) and mechanical property tester were used to characterize the structure and properties of PC/PLA blends．It showed that PLA-b-PMMA improved the compatibility of PC and PLA, and the degree of compatibility mainly depended on the block length in PLA-b-PMMA. A PC/PLA blend with satisfied morphology and mechanical properties was obtained when the content of PLAbPMMA was 6 %. With PMMA chain length in PLA-b-PMMA being 60000, the compatibility of PC and PLA in the blends continued to get better as the PLA chain length increased from 3390 to 9780. However, with PLA chain length in PLA-b-PMMA being 9780, the compatibility of PC/PLA blends came down as the PMMA chain length increased from 20680 to 99680.

Sulfur Modified Polypropylene Fiber Materials and the Rheological Behavior Research

2015, 29 (12): 46-51 ; DOI: 10.19491/j.issn.1001-9278.2015.12.009

Abstract ( 796 )

Initiated by DCP, sulfur grafted polypropylene(PP-g-S) was prepared in melt, which was used as a compatibilizer in a fiber material PP/PP-g-s/S. The compatibilizer was analyzed by Haake torque rheometer, infrared spectrometer, nuclear magnetic resonance, melt flow indexer, and SEM. The effect of dosage of sulfur on the dynamic rheological behavior of PP/PP-g-S/S fiber was studied using a rotating plate rheometer. It was found that sulfur was homogeneously dispersed. With increasing sulfur content, all the complex viscosity, storage modulus, loss modulus, and loss factor, radius of ColeCole curve, zero shear viscosity increased.

Preparation and Investigation on the Properties of PP/Rare Earth Strontium Aluminate Luminescent Materials

2015, 29 (12): 52-55 ; DOI: 10.19491/j.issn.1001-9278.2015.12.010

Abstract ( 912 )

Polypropylene(PP)/rare earth strontium aluminate (RESA) composites were prepared by melt blending. The effect of the content of RESA on the crystallization behavior, mechanical and optical properties was studied. It showed that the crystal structure of PP did not change with the inclusion of RESA. Due to the effect of heterogeneous nucleation, the crystallinity of the composites increased, the spherulites became smaller and more uniform with increasing RESA loading. The tensile strength and elongation at break increased first and then decreased. The initial light intensity increased with increasing content of RESA. The light intensity curve showed a typical exponential attenuation.

Mechanical Properties of Jute Fiber Grafted Cardanol Unsaturated Polyester Composites and Interface Regulation

2015, 29 (12): 56-61 ; DOI: 10.19491/j.issn.1001-9278.2015.12.011

Abstract ( 806 )

A macromolecular coupling agent, which was prepared from toluene diisocyanate (TDI) and cardanol (CNSL), was grafted on jute fibers, the obtained fiber was used as reinforcement in composites of unsaturated polyester resin (UPR). The tensile strength, elongation at break, and impact strength of pure UPR, 5 % CNSL toughening UPR, 25 % of alkalitreated jute fiber UPR composites, and 25 % grafted jute fiber UPR, 25 % grafted jute fiber and 5 % CNSL UPR composites were compared. It was found that the addition of CNSL improved the toughness of the composite, jute fibers improved the tensile strength. 25 % CNSL grafted jute UPR could improve both the tensile strength and toughness. 25 % CNSL grafted jute fiber and 5 % CNSL toughened UPR composite provided a toughness of 12.10 kJ/m^2.

Simulation Analysis and Experimental Study of the Molding Process for PA6/PE-LD Blends Casting Film

2015, 29 (12): 62-66 ; DOI: 10.19491/j.issn.1001-9278.2015.12.012

Abstract ( 1052 )

The influence of air gap and draw ratio on thickness and neckin of polyamide 6/low density polyethylene(PA6/PE-LD) casting film was studied through simulation and experiment. It was found that the draw ratio was more influential than air gap on thickness, and the air gap was more influential than draw ratio on neckin.

Effect of Injection Velocity on Crystall Morphology of Injection Molded Parts

2015, 29 (12): 67-72 ; DOI: 10.19491/j.issn.1001-9278.2015.12.013

Abstract ( 976 )

The effect of injection speed on the crystallization properties of polypropylene (PP) was studied. Plotting crystallinity vs. injection velocity a “Λ” shaped curve was obtained. The orientation and lattice distortion increased, while the crystallite dimension decreased with increasing injection speed. The order of the parameters sensitive to injection speed was crystallite dimension, crystallinity, lattice distortion, orientation, crystal form.

Research on Mechanical Properties of PA12 Products by 3D Printing

2015, 29 (12): 73-76 ; DOI: 10.19491/j.issn.1001-9278.2015.12.014

Abstract ( 802 )

In this paper, fused deposition modeling (FDM) and selective laser sintering (SLS) were employed to prepare 3D printed polyamide 12 samples. The effect of orientation in 3D printing on samples was studied and compared with injection molded ones. The tensile strength and elongation at break of FMD samples could be 56.3 % and 60.9 % of those for injection molded ones, respectively. In contrast, the tensile strength of SLS samples was greater than 90 % of injection molded ones, however, the elongation at break was below 10 % of injection molded ones.

Effect of Wall Thickness on Microtubule-extrusion Molding

2015, 29 (12): 77-81 ; DOI: 10.19491/j.issn.1001-9278.2015.12.015

Abstract ( 867 )

Based on the Bird-Carreau viscosity model, a threedimensional isothermal numerical model was established for the microtubuleextrusion molding by the finite element method, with the emphasis on the influence of the wall thickness, die swell, velocity distribution, shear rate distribution, pressure drop in the microextrusion molding. It showed that the swell and deformation of the extrudate increased with increasing wall thickness when the polymer melt flow rate was equal under different wall thickness condition. The melt secondary flow enhanced at the die exit plane, but the extrusion speed, shear rate and pressure drop within the die decreased with increasing wall thickness. It was conducive to improve the product quality if the wall thickness was increased appropriately.

Study on Polypropylene/Glass Fiber Water Tank Supporters Based on the Finite Element Analysis

2015, 29 (12): 82-85 ; DOI: 10.19491/j.issn.1001-9278.2015.12.016

Abstract ( 1218 )

Supporters of automobile water tanks made of polypropylene/glass fibers was studied by using computer Catia and UG software to analyze the strength and stiffness. Compared with supporters made of traditional materials, it had some advantages, such as lightweight. The findings in the analysis was employed in the improvement of supporters.

Effects of Coupling Agents on the Luminescence and Rheological Behavior of Rare Earth Fluorescent Bamboo Plastic Composites

2015, 29 (12): 86-90 ; DOI: 10.19491/j.issn.1001-9278.2015.12.017

Abstract ( 800 )

The effect of three coupling agents (MAPE, KH-560, and YB-510) on the luminescence and rheological behavior of rare earth containing bamboo/plastic composites was investigated. Emission spectrum showed that three kinds of coupling agent reduced the complex viscosity and improved the processing fluidity of the composites. The coupling agents enhanced the dispersion of strontium aluminate phosphors and the relative luminous intensity, with MAPE being the most effective. Frequency scan showed that the storage modulus (G′) and loss modulus (G″) increased linearly with increasing frequency, and leveled off on the highfrequency region. At low frequency region, in which the filler and matrix formed a network structure, the dependency of “solidlike behavior” on frequency was weak.

Flame Retardancy of Dibromoneopentyl Glycol on Linear Low Density Polyethylene

2015, 29 (12): 91-95 ; DOI: 10.19491/j.issn.1001-9278.2015.12.018

Abstract ( 960 )

An intumescent flame retardant (IFR) containing dibromoneopentyl glycol (DBNPG), pentaerythritol (PER), and microencapsulated ammonium polyphosphate (APP) was introduced into linear low density polyethylene (PE-LLD). Experimental results proved that an appropriate content of DBNPG improved the compatibility of PE-LLD and IFR, enhanced the tensile properties and the melting viscosity, promoted the formation of a closed char layer. However, excessive DBNPG content lowered the soften temperature of IFR, decreased the melt viscosity, and thus destroyed the closeness of the char layer, deteriorated the thermal barrier property, weakened the flame retardancy. When the ratio of PER/DBNPG was 70.0/115.5, and the ratio of PELLD/IFR was 70/30, the composite exhibited the optimal flame resistance.

Injection Molding Filling Disequilibrium Analysis and Runner Design Improvements

2015, 29 (12): 96-100 ; DOI: 10.19491/j.issn.1001-9278.2015.12.019

Abstract ( 1145 )

In the paper, the problem of nonuniform filling in a multicavity mold was explored by numerical simulation with a simplified model. It was found that it was the difference in the heat generated in different runners that caused the difference in flow fields, and resulted in that the cavities could not be filled simultaneously. Based on this argument, different geometries grooves were designed in the site of runner cross in order to change the temperature field of subrunner entrance. The simulation showed that two cavities could be almost simultaneously filled.

Characteristics Analysis of Polymer Materials in Compliant Mechanisms Design

2015, 29 (12): 101-105 ; DOI: 10.19491/j.issn.1001-9278.2015.12.020

Abstract ( 1137 )

The effect of material properties on compliant mechanism were studied in aspects of the deformation ability, dynamic performance, static failure, and fatigue failure. Firstly, the relationship between the material parameters and the maximum deformation, natural frequency of flexible member was analyzed. Then, the influence of material properties on the static failure and fatigue failure of compliant mechanisms was discussed. Finally, the superiority and challenge of the polymeric materials in the design of compliant mechanisms were summarized.

Influence of Gates on Flow Marks of Injection Molded Parts

2015, 29 (12): 106-109 ; DOI: 10.19491/j.issn.1001-9278.2015.12.021

Abstract ( 1356 )

The reason for flow marks on injection molding parts was discussed. It was confirmed through experiment that the type and location of the gate were the key factors controlling the flow mark.