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2014, Volume 28 Issue 08 Publication date: 26 August 2014 Previous Issue Next Issue

Progress in Preparation of Starch-Based Biodegradable Plastics

2014, 28 (08): 1-6 ; DOI: 10.19491/j.issn.1001-9278.2014.08.001

Abstract ( 532 )

Properties of thermoplastic starch (TPS) were briefly introduced. Research development of blends of TPS with synthetic polymer, including poly(lactic acid)(PLA), poly(εcaprolactone(PCL), acid alcohol copolyester, poly(propylene carbonate)(PPC), poly(vinyl alcohol)(PVA) and natural polymer was reviewed. In the end, problems and development direction of starchbased biodegradable plastics were forecast.

Development of the reasearch on modification to natural fibers for manufacturing the biocomposite

2014, 28 (08): 7-12 ; DOI: 10.19491/j.issn.1001-9278.2014.08.002

Abstract ( 491 )

Surface modification methods for natural fibers used for biocomposites were reviewed. Various surface treatment methods such as those using alkali, enzyme, and coupling agent were summarized. Merits and drawbacks of these modification methods were analyzed and the new research trend of natural fibers modification technology was pointed out.

Effects of G-POSS on the Curing Process and Mechanical Properties of G-POSS/CE Hybrid Materials

2014, 28 (08): 13-16 ; DOI: 10.19491/j.issn.1001-9278.2014.08.003

Abstract ( 487 )

A hybrid material was prepared via meltblending method from glycidyl polyhedral oligomeric silsesquioxane (GPOSS) and bisphenolA dicyanate ester (CE). The structure of the hybrid was characterized by Fourier transform infrared spectrometer (FTIR), scanning electron microscope (SEM), and its properties were tested. It was revealed that the GPOSS could obviously accelerate the curing reaction of the resin. The toughness of the matrix was improved by GPOSS. The impact strength of GPOSS/CE hybrid materials was 238 kJ/m2, which increased 158 % compared with that of neat CE, when the content of GPOSS was 7 phr.

Study on Flame Retardant of Bamboo Flour/Polylactic Acid Composites Water Absorption

2014, 28 (08): 17-21; DOI: 10.19491/j.issn.1001-9278.2014.08.004

Abstract ( 839 )

Flame retardant poly(lactic acid)/bamboo flour composites were prepared with aluminium hydroxide（ATH）, ammonium polyphosphate (APP), and APP/ATH blends as a flame retardant. Water absorption and mechanical properties of APP/ATH blends were tested after being soaked in water for various length of time. The tensile strength and impact strength properties of composites were decreased after being the soak treatment, in which the tensile strength decreased by nearly 90 % after being soaked 4 d. The blend containing either APP or ATH alone had low water absorption and thickness swelling rate，and those containing both APP and ATH provided the highest water absorption and the worst dimensional stability.

Preparation and characterization of flame retardant co-microencapsulate of magnesium hydroxide and aluminum hydroxide

2014, 28 (08): 22-26 ; DOI: 10.19491/j.issn.1001-9278.2014.08.005

Abstract ( 542 )

A mixture of aluminum hydroxide (ATH) and magnesium hydroxide (MH) was microencapsulated by melamineformaldehyde (MF) by insitu polymerization under alkaline condition. The product（MMA）was characterized by Fourier transform infrared spectrometer (FTIR), scanning electron microscope (SEM) and thermogravimetry (TG). The flammability and mechanical properties were evaluated using limiting oxygen index test and universal testing machine, respectively. FTIR showed that the bands from 1600 to 1300 cm-1 assigned to the MF emerged in MMA. SEM indicated that MF had an effect on the growth of MA crystals, and the particle diameter reduced in MMA. The limiting oxygen index and mechanic property testing showed that MMA possessed improved flame retardacy and better mechanical property than MA.

Study on Thermoplastic Starch Toughing Nylon 6

2014, 28 (08): 27-30; DOI: 10.19491/j.issn.1001-9278.2014.08.006

Abstract ( 514 )

Polymeric blends were prepared via melt mixing from polyamide 6 (PA6) and glycerol plasticized thermoplastic starch (TPS). The influence of glycerol on the property of PA6/TPS blends was investigated, and the toughening mechanism of the blends was explored as well. By adding TPS, the impact strength and the tensile modulus of the blends increased, while the tensile strength and the melt flow rate slightly declined, which revealed that TPS acted as rigid particles. The scanning electron microscope (SEM) images for the impact fractured surface of the samples suggested that the main toughing mechanism of PA6/TPS blends was the interfacial voiding effect. In addition, the content of glycerol and TPS played a notable role in the toughening effect. When the TPS content was 25 %, the impact strength was increased by 630 % based on neat PA6.

Modified Graphite - Phenolic Resin Coated Flame Retardant Polystyrene

2014, 28 (08): 31-35; DOI: 10.19491/j.issn.1001-9278.2014.08.007

Abstract ( 523 )

Graphite oxide (GO) was introduced into phenol resin (PF) by in situ intercalative polymerization. The obtained phenol (PG) was coated on the surface of expandable polystyrene (EPS) as a flame retardant, which was processed to thermal insulation board. The flame retardant, thermal, and mechanical properties were tested. It showed that the flame retardancy of EPS increased significantly by the coating of PG, however, the thermal and mechanical properties were declined when the GP or GO contents were too high.

Relationship between Bridged group and Antioxidation of Aliphatic Diamine Bridged Hindered Phenol

2014, 28 (08): 36-41; DOI: 10.19491/j.issn.1001-9278.2014.08.008

Abstract ( 510 )

Series of hindered phenols were synthesized using 3-(3,5-diterbutyl-4-hydroxyphenyl) methyl propionate as a raw material and aliphatic diamine as a bridge group. The obtained phenols were characterized by Fourier transform infrared spectrometer (FTIR) and 1Hnuclear magnetic resonance (1HNMR). The effect of the bridged group on the antioxidation of hindered phenols was studied. It showed that the bridge group rendered the material excellent processing property, thermal oxidative resistance, and mechanical properties. All those properties were enhanced with increasing carbon number of the bridge group. The effect of the bridge group in PELLD was more obvious than that in PP.

Preparation and Characterization of Polyimide/Polyaniline/Carbon Black Antistatic Composite Film

2014, 28 (08): 42-46; DOI: 10.19491/j.issn.1001-9278.2014.08.009

Abstract ( 441 )

Antistatic polyimide (PI) composite film was prepared by insitu polymerization method, with conductive carbon black (CB) and polyaniline as conductive modifiers. The electrical property of the composite film was studied at different PANI and CB contents. Its morphology was observed by electron microscopy. The thermostability and mechanic propreties were analyzed. It showed that the dispersion of the fillers in the composite film was far better than that filled with either CB or PANI alone. The surface resistance of the composite meet the requirement of antistatic behavior, and the thermal stability was the best when the ratio of PANI to CB was 1∶2.

Effects of Fiber Surface Modification on Properties of RF/PP Composites

2014, 28 (08): 47-51; DOI: 10.19491/j.issn.1001-9278.2014.08.010

Abstract ( 506 )

Polypropylene/ramie fiber (PP/RF) composites were prepared by melt blending. The effects of the fiber surface modification were assessed by electronic universal testing machine, scanning electron microscope (SEM), differential scanning calorimeter (DSC), HDTVICAT tester, and coefficient of linear expansion tester. When RF was modified, the impact strength and Vicat softening temperature of PP/RF composites was improved, and crystallinity and linear expansion coefficient decreased gradually. The crystallinity was the lowest in all the studied samples when RF was treated with POEgMAH. While RF was treated with alkali, the linear expansion coefficient was the smallest.

Effect of Strong Shearing Action on the Structure and Properties of Fullstarch Plastics

2014, 28 (08): 52-57; DOI: 10.19491/j.issn.1001-9278.2014.08.011

Abstract ( 474 )

Thermoplastic starch plastics was prepared by using glycerol and sorbitol as plasticizers，and a single screw extrusion equipment with deep screw grooves, short pitch, and long shear zone was designed to enhance shear action and improve the mechanical properties of thermoplastic fullstarch plastics. The effects of strong shearing on the fullstarch plastics using scanning electron microscopy, infrared spectroscopy, thermal analysis, and Xray diffraction. It showed that the hydrogen bonds were formed between plasticizer and starch granules, the spherulite structure of the starch granule was destroyed, which made the starch form a homogeneous phase structure after extrusion. Compared with normal extrusion process, the material at break extruded by the newly designed extruder gave a better thermal stability, moreover, the tensile strength increased by 172 %, and the elongation at break decreased by 18 %.

Synthesis and application of the novel bromomaleic silicate flame retardants

2014, 28 (08): 58-61; DOI: 10.19491/j.issn.1001-9278.2014.08.012

Abstract ( 397 )

Silicate tris(2,3-dibromopropyl) tribromophenyl ester was synthesized from tribromophenol, silicon tetrachloride, and 2,3-dibromopropanol. The effect of charging order, solvent, reaction temperature, reaction time, and composition on the reaction yield was also discussed. The above ester was introduced into PVC and the molecular structure and property of the system were characterized by means of FTIR, 1HNMR, and limited oxygen index. It was found that the limited oxygen index of the PVC compound containing silicate tris(2,3dibromopropyl) tribromophenyl ester was 395 %,and had a good effect on antiflaming, plasticizing, charring, and antidripping.

Research on New Method and Technology Optimization for Electrofusion Joints in PE Pipes

2014, 28 (08): 62-65; DOI: 10.19491/j.issn.1001-9278.2014.08.013

Abstract ( 529 )

An eigenline in the electrofusion joint was observed by using the phased array ultrasonic focusing technique. A new method called “eigenline method” was developed to assess cold welding with an empirical formula by measuring the distance between the line and metal wires. Further research showed that the developed method could be used to assess the welding technology in ultrasonic test realtime video by measuring the moving speed of the eigenline and the distance between the line and metal wires. Based on ultrasonic test realtime video experiments and the developed theoretical model of welding process for electrofusion joints, the optimized welding technology for the joint was obtained, which greatly reduced the time and cost in development of electrofusion joints.

Analysis of Mixing Performance in a Intermeshing Corotating Asymmetric Twinscrew Extruder

2014, 28 (08): 66-71; DOI: 10.19491/j.issn.1001-9278.2014.08.014

Abstract ( 445 )

An asymmetric model for the crosssection geometry of a intermeshing corotating asymmetric twinscrew extruder was proposed, and the mixing characteristics of it were analyzed by both experimental investigation and numerical simulation. The experimental characterization was conducted using an active nanometer CaCO3 filled PELLD with a novel corotating asymmetric twinscrew extruder and a traditional corotating twinscrew extruder, keeping a fixed output. Scanning electron microscope (SEM) micrographs revealed that nanoCaCO3 in the composites extruded by the novel corotating asymmetric twin screw extruder was more uniform with smaller particle sizes, and it showed an obvious toughening effect, which agreed with the numerical simulation results.

Rheological and Foaming Behavior of PS/PETG Blends

2014, 28 (08): 72-77; DOI: 10.19491/j.issn.1001-9278.2014.08.015

Abstract ( 531 )

Polystyrene and poly (ethylene terephthalate glycol) (PS/PETG)blends were prepared by an internal mixer.PS and PS/PETG foams were prepared by the batch method using supercritical CO2 as the foaming agent.The rheological properties and cellular morphology were characterized by dynamic rotational rheometer and scanning electron microscope. The results showed that the addition of PETG has no significant effect on the rheological properties of PS ,but obvious effect on the cell size morphology of PS. The average cell diameter decreased from 22.68 μm to 7.58 μm and the cell density increased from 3.45×108cell/cm3to 4.47×109cell/cm3 when adding 10 % PETG into PS. The cell distribution also became narrow. Thus PETG can serve as the nucleation agent when blended with PS.

Thermal Stabilization of Cyanoacetylurea in PVC

2014, 28 (08): 78-83 ; DOI: 10.19491/j.issn.1001-9278.2014.08.016

Abstract ( 458 )

By comparison with tribasic lead sulfate (TLS) and N,N-dimethyl-6-aminouracil (DMAU), the thermal stabilization of N,N-dimethylcyanoacetylurea (DMCAU) in poly(vinyl chloride)(PVC) was studied by Congo red and oven aging method. It showed that the thermal stability of DMCAU based system was similar to that based on DMAU. When DMCAU was used alone and the dosage was low, the Congo red test time was longer than that of TLS. With increasing dosage, the increase in test time was far slower than TLS, and the inhibiting effect for PVC′s discoloration in oven was no better than TLS. When DMCAU was used with CaSt, a synergistic effect was observed in Congo red test, and the optimal proportion was 1∶1.

Preparation and Application of Lanthanum Itaconate Compound Thermal Stabilizer for PVC

2014, 28 (08): 84-89; DOI: 10.19491/j.issn.1001-9278.2014.08.017

Abstract ( 422 )

Lanthanum itaconate was synthesized by saponification method, which was mixed with other components forming a compound thermal stabilizer for PVC. Thermal stability mechanism of PVC containing the compound stabilizer was studied by Congo red testing and FTIR. Processing performance and mechanical properties of the PVC compounds were determined by torque rheometer process tests and dynamic mechanics spectrometer. It showed that the best ratio was lanthanum itaconate∶pentaerythritol∶calcium stearate∶βdiketone was 3.5∶1∶1∶1. The static and dynamic thermal stability time reached 66.0 and 36.8 min, respectively, the early coloring of PVC was restrained. Processing performance and mechanical properties were similar to those of lead salt and lanthanum stearate compound systems and better than those of calcium zinc complex system. The FTIR showed that the compound thermal stabilizer could lower the reaction rate of HCl eliminating, and inhibit the formation of conjugated polyene at the beginning of the heating, and thus the thermal stability was improved.

Research of the Key Technologies of Integration on the Appearance and the C Surface of All-plastic Car Body

2014, 28 (08): 90-93 ; DOI: 10.19491/j.issn.1001-9278.2014.08.018

Abstract ( 442 )

This paper presents the key technology on the lightweight design of allplastic car bodies.According to the characteristics of rotational molding, the mold design, and process requirements，the structure of allplastic car bodies was designed reasonably, which met the overall appearance in order that the structure matched with the function well.They were mainly reflected in the combination of the whole car body, the lampshade, the fender,the hood, and other key parts in order to achieve the integration and lightening on the structure of design.

Effect of Injection Molding Processing Parameters on Warpage Deformation of Automobile Light Lens Made of PC

2014, 28 (08): 94-98; DOI: 10.19491/j.issn.1001-9278.2014.08.019

Abstract ( 543 )

Based on orthogonal experiments, the injection molding of automobile light lens made of PC was simulated with Moldflow software. The effect of injection molding parameters including melt temperature, mold temperature, injection time, packing pressure, and packing time on the warpage deformation of the lens were analyzed systematically, and the optimum process parameters were obtained. The amount of warpage deformation of the lens was greatly decreasing when the injection molding was simulated with the optimum parameters.

CAE-based Ameliorative Design for Solving Warpage On Thin-wall Plastic Parts

2014, 28 (08): 99-102; DOI: 10.19491/j.issn.1001-9278.2014.08.020

Abstract ( 438 )

The causation and resolving of warpage on the injection molded plastic shell were studied. The effect of location and number of gate on warpage of products were analyzed though simulating the injection molding for the complicated plastic by Moldflow. The optimal location, number of the gate and the structure of injection mold were determined through simulation. The problem of warpage on the complicated plastic parts was effectively solved. In practice plastic parts with high quality were obtained.