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2013, Volume 27 Issue 06 Publication date: 26 June 2013 Previous Issue Next Issue

Research Progress in Flame Retardant Masterbatch

2013, 27 (06): 1-6 ; DOI: 10.19491/j.issn.1001-9278.2013.06.001

Abstract ( 1549 )

in this paper, the preparation process of the flame retardant masterbatch was introduced, and the recent research development of the flame retardant masterbatch for fibers and plastics was summarized.

Research Progress in Solid Materials Surface Modified by Polydopamine

WEN Bianying

2013, 27 (06): 7-12 ; DOI: 10.19491/j.issn.1001-9278.2013.06.002

Abstract ( 1972 )

In this paper, the property of dopamine and its polymerization mechanism were introduced. The modification effect and method on the surface of some organic or inorganic substrates with polydopamine coating were reviewed; and the further functional modification which base on the polydopamine coating was also introduced.

Research Progress in Polymer/Coal Composites

2013, 27 (06): 13-18 ; DOI: 10.19491/j.issn.1001-9278.2013.06.003

Abstract ( 1653 )

This article introduced the surface treatment methods of coal (coupling agent processing, oxidation treatment and surface grafting) and summarized the latest achievements on improving the properties (including mechanical, electrical properties, thermal stability, and flame retardant property) of polymer/coal composites. The development tendency of polymer/coal composites was discussed.

Studies on Craxes Inside Polymeric Materials

2013, 27 (06): 19-22 ; DOI: 10.19491/j.issn.1001-9278.2013.06.004

Abstract ( 1783 )

The recent advance in the study on polymer craze was viewed. The content includes craze definition, classification, initiation, growth, fracture. Meanwhile, the challenges and problems on the research of the polymer craze were discussed.

Joint Effects of β-crystals Content and Their Morphology on the Toughness of Isotactic Polypropylene

2013, 27 (06): 23-27 ; DOI: 10.19491/j.issn.1001-9278.2013.06.005

Abstract ( 1398 )

A series of N,N'-dicyclohexylterephthalamide (DCHT) in different size were prepared via resizing via ultrasonic oscillations. The effect of size on the mechanical properties, the content of β-crystals, and supermolecular structure of isotactic polypropylene (iPP) was studied. It was found that the size of β-nucleating agent could affect the solubility of DCHT in iPP, thus the β-nucleated crystalline morphology changed. Two types of β-form crystalline morphology, namely, "flower"-like agglomerate and β-transcrystalline entity were sequentially observed with increasing content of DCHT. Therefore, it was concluded that β-crystals content might mainly determine the toughness of iPP with the same supermolecular structure. However, β-crystalline morphology should play a dominant role in the toughing of iPP with different supermolecular structure.

Investigation on Flame Retardancy and Mechanical Property of Chemical Cross-linked EVA/NBR Composites

2013, 27 (06): 28-32 ; DOI: 10.19491/j.issn.1001-9278.2013.06.006

Abstract ( 1439 )

In this paper, halogen free flame retardant EVA/NBR composites containing magnesium hydroxide [Mg(OH)2] and red phosphorus (RP) were prepared via melt blending through a two-roll mill. Limiting oxygen index, cone calorimeter, tensile test, and thermal gravimetric analysis were used to characterize the effect of dicumyl peroxide (DCP) and maleic anhydride grafted ethylene-vinyl acetate copolymer(EVA-g-MAH) on the flammability, mechanical properties, and thermal behavior of EVA/NBR composites. The limiting oxygen index value reached 38.4 % and the heat release rate decreased from 941 to 690 kW/m2; the tensile strength reached 17.4 MPa, and elongation at break increased to 1236 %; the starting mass loss temperature increased from 321.6 to 327.0 C, and the residual mass increased from 10 to 32.1 % at the presence of 10 phr EVA-g-MAH after cross-linking. The morphology of cryogenically fractured surface was observed and analyzed using scanning electron microscope (SEM) and it showed that the fractured surface was compact and fillers disperse evenly.

Research on Crystallinity and Impact Property of PE-UHMW Resin

2013, 27 (06): 33-37 ; DOI: 10.19491/j.issn.1001-9278.2013.06.007

Abstract ( 1173 )

The impact property of ultra-high molecular weight polyethylene (PE-UHMW) resin was studied via "double notched" Charpy impact property tests. The influencing factors was analyzed through single factor experiment and variance analysis, the relationship among the crystallization behavior, impact property, motions of molecular chain, free volume, and the interaction of molecules was formulated. The major factor in the processing of PE-UHMW was finally determined through uniform design and step regression being the pressing temperature.

Study on Compatibility of ABS/PET Alloy

YAO Xiu-Chao LV TongJian LV

2013, 27 (06): 38-41 ; DOI: 10.19491/j.issn.1001-9278.2013.06.008

Abstract ( 1657 )

This paper introduced the research on compatibility in alloys of acrylonitrile-butadiene-styrene copolymer/polyethylene terephthalate (ABS/PET), using methyl methacrylate-butadiene-styrene copolymers (MBS), KT-18, KT-5A as compatibilizers. The alloys were prepared via twin-screw extrusion. It showed that the best loading of PET in the alloy was 20 % ~ 30 %. KT-18 constituted the best compatibilizer. When and the dosage of KT - 18 was 3 % ~ 5 %, the impact strength of ABS/PET alloy reached 8.79 kJ/m2.

Preparation and Characterization of Polyimide/Polyaniline Conductive Composites

2013, 27 (06): 42-46 ; DOI: 10.19491/j.issn.1001-9278.2013.06.009

Abstract ( 1233 )

Polyimide/polyaniline anti-static and anti-puncture composite film was prepared via in-situ polymerization. The function groups and the degree of polymer imidization were characterized using FTIR spectroscopy. The surface resistance, volume resistance, breakdown，mechanical properties, and thermal properties were characterized using insulation resistance measurement instrument, program-controlled voltage tester，electronic universal testing machine, and thermal mechanical analyzer. It showed that when the content of polyaniline was 15 %, the anti-static of composite film was best and good mechanical properties of polyimide were remained.

Effect of Interface Modification on Properties of Bamboo Fiber Reinforced Poly（lactic acid） Composites

Xingong LI

2013, 27 (06): 47-51 ; DOI: 10.19491/j.issn.1001-9278.2013.06.010

Abstract ( 1256 )

Bamboo fiber was surface modified with isocyanate (MDI) and used to reinforce poly(lactic acid) through injection molding. Interface, mechanical, and thermal properties of the resulted composites were investigated. As MDI addition increased, tensile strength of composites gradually increased，impact strength first increased and then decreased. When MDI addition was 1.5 %, tensile strength and impact strength of composites reached the maximum of 63.4 MPa and 11.3 kJ/m2, respectively. The storage modulus of composites gradually increased, loss factor gradually decreased, glass transition temperature, crystallization temperature and pyrolysis temperature of composites increased, thermal stability of composites increased with increasing MDI content.

Effect of Natural Weathering on Molecular Structure of Polystyrene in Typical Dry-hot Environment

2013, 27 (06): 52-55 ; DOI: 10.19491/j.issn.1001-9278.2013.06.011

Abstract ( 1293 )

In order to study the molecular structure changes of polystyrene in natural dry-hot environment, outdoor exposure test was performed in Turpan and Ruoqiang for one year, FTIR, GPC, and DSC analysis were performed thereafter. It showed that photo-degradation and chain scission occurred, resulting in the decreasing of molecular weight, broadening of molecular weight distribution, and lowering of glass transition temperature.

Study on Properties of PA66/Tin Fluorophosphate Glass Hybrids

2013, 27 (06): 56-60 ; DOI: 10.19491/j.issn.1001-9278.2013.06.012

Abstract ( 1162 )

The PA66/tin fluorophosphate glass (TFP) hybrids were prepared via powder-mixing, melt-blending, and injection molding. The dynamic mechanical properties, crystallinity and morphology of hybrids were investigated. When 30 % TFP was loaded, the Tg of PA66 decreased by 13℃. The addition of TFP led to decreases the contents crystallizing rates of α and γ crystal forms of PA66. TEP was finely dispersed in PA66 matrix and exhibited good compatibility with the matrix.

Preparation and Performance of Biodegradable Hydrophobic Polyurethane Film

2013, 27 (06): 61-65 ; DOI: 10.19491/j.issn.1001-9278.2013.06.013

Abstract ( 1206 )

Degradable hydrophobic PU film was prepared from polylactic acid (PLA) and plastic polyurethane (TPU) via phase separation method. Various preparation parameters were adjusted including the ratio of raw materials, solution treatment temperature and time. When the full dissolution time of PLA and TPU in THF was 45 min, the treatment time of solvent was 80 min, and the treatment temperature of solvent was 45 C, a contact angle of 142.8° was observed. The degradation rate of the film was 9.14% at the ninth day. The SEM image of the film showed a honeycomb-like texture.

Research of Glue Bonding Strength for Co-extrusion Profile Strips

2013, 27 (06): 66-69 ; DOI: 10.19491/j.issn.1001-9278.2013.06.014

Abstract ( 1180 )

The structure of co-extruded adhesive profile strip was introduced. Several measures were proposed to improve the adhesive strength of the strip, including adjusting the raw materials formula, air preheating device, installing the gradient supercharged port, controlling the fusing length and angular, etc.

Preparation and Properties of Starch-based Biodegradable Film

Lei XU

2013, 27 (06): 70-74 ; DOI: 10.19491/j.issn.1001-9278.2013.06.015

Abstract ( 1629 )

A starch-based biodegradable film was prepared from linear low density polyethylene (PE-LLD), low density polyethylene (LDPE), epichlorohydrin (EDH) and modified-corn starch using epoxy soybean oil as a plasticizer, a small amount of ethylene propylene diene monomer (EPDM) was used as a compatibilizer. The film could maintain excellent mechanical properties with content of modified starch up to 70%. FTIR was used to characterize the modified starch and SEM was used to observe the morphology of the film before and after the modification. When a rotating mould head was used, the maximum content of starch could be further increased.

Effect of PE-HD-g-MAH on the Friction and Wear Behavior of PA 66/PE-UHMW Blends

2013, 27 (06): 75-80 ; DOI: 10.19491/j.issn.1001-9278.2013.06.016

Abstract ( 1240 )

High density polyethylene was grafted with maleic anhydride (leading to PE-HD-g-MAH), which was introduced into blends of ultra high molecular weight polyethylene (PE-UHMW) and polyamide 66 (PA66) to improve its mechanical and tribological behavior. The micro-structure, wear and friction transfer film surface of the blends were analyzed using SEM, the viscoelastic behavior of the blend were tested using the DMA and capillary rheometer, the chemical characteristic peaks of the blends were analyzed using FT-IR before and after friction. It showed that PE-HD-g-MAH improved the compatibility between PA66 and PE-UHMW and the tensile, bending, and impact strengths were improved. With increasing PE-HD-g-MAH, friction coefficient of the blends decreases gradually. No chemical reaction occurred during the frictional process. PE-HD-g-MAH also improved the temperature resistance of the blend. The fatigued wear was shown on the worn surface. The addition of PE-HD-g-MAH inhibits the growth of fatigue crack, so that the homogeneous transfer film became uniform gradually.

Preparation of Novel Organic Montmorillonite and Its Application in Polypropylene

2013, 27 (06): 81-86 ; DOI: 10.19491/j.issn.1001-9278.2013.06.017

Abstract ( 1228 )

The PP/OMMT nanocomposites were prepared via melt blending PP with organic modified montmorillonite (OMMT) which was prepared from cetrimonium bromide(CTAB), epoxy resin, isophorone diisocyanate (IPDI), octadecylamine (ODI) as intercalation agents. FTIR and XRD were applied to study the structure of the modified montmorillonite (OMMT). The morphology of the nanocomposites (PP/OMMT) was characterized using TEM, and the mechanical properties were also studied. The space of the montmorillonite layers increased from 1.56nm to 4.28nm, and the OMMT layers were dispersed uniformly in the PP matrix. When the content of the OMMT was 5%, the tensile strength, the elongation at break, and the impact strength increased by 25.9%, 17.1% and 127.1% , respectively, based on neat PP. In addition, the crystallinity of PP was increased first and then decreased.

Optimization of Gate Location of Plastic Mould with Variable Thickness and Section

2013, 27 (06): 87-90 ; DOI: 10.19491/j.issn.1001-9278.2013.06.018

Abstract ( 1197 )

The factors affecting the quality and capability of plastic parts were quantitatively analyzed and optimization a model of gate location of plastic mould with changeable thickness and section was formulated based on genetic algorithm and numerical simulation. After optimization, the pressure of gate location, the temperature difference, and the maximum shear stress were reduced by 25 %, 31 %, 8 %, respectively, and numerical examples were given to demonstrate the function of the optimization model.

Simulation of Three-dimensional Flow in Differential Twin-screw Extruders

WANG Ke-jian

2013, 27 (06): 91-96 ; DOI: 10.19491/j.issn.1001-9278.2013.06.019

Abstract ( 1892 )

Three-dimensional simulation and mixing analysis were conducted for melt flow in screw groove of differential twin screw extruder using Polyflow. In view of shear rate, stretch rate, and mixing index, the mixing with differential ratio of 5:1.was better than that with 4:1.

Analysis on Clamping Mechanism of Large Injection Molding Machines

YUE Qin-Yang ZHOU Hong-wei WU LIN

2013, 27 (06): 97-100 ; DOI: 10.19491/j.issn.1001-9278.2013.06.020

Abstract ( 1201 )

Motion analysis of negative-rear angle clamping toggle mechanism was carried out, the stationary, rear, and moving plate structure were modeled and analyzed. The speed ratio of moving plate to clamping cylinder of the injection molding machine was related with the clamping mechanism parameters. There was no self-locking of negative-rear angle in the opening mold process, and the clamping process followed a slow-fast-slow mode. In the high-pressure clamping area，the speed of moving plate dropped very quickly. The structure of three plates was optimized through limited element analysis.