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2010, Volume 24 Issue 11 Publication date: 26 November 2010 Previous Issue Next Issue

Technological Innovation—Way out for PVC Pipes Industry in China

2010, 24 (11): 1-5 ; DOI: 10.19491/j.issn.1001-9278.2010.11.001

Abstract ( 2082 )

The develop stratagem of China's PVC pipes industry was discussed. The challenge and opportunity in this industry was analyzed. It was indicated that we must change the development mode and optimize the structure and follow the path of technique innovation. We must stop blindly expanding production capacity and avoid repeat investment on low level products. The suggestions about the market expansion and new products development of PVC pipes industry was proposed.

Current State and Development Trends of New-materials-based Light Conveyor Belts in China

XU Qian-Wei

2010, 24 (11): 6-10 ; DOI: 10.19491/j.issn.1001-9278.2010.11.002

Abstract ( 2163 )

Characters of the new material light conveyor belts and their current situation and trend were reviewed in this article. The new material light conveyor belts were made of synthetic fabric or non-woven coated with thermoplastics or elastomer, rather than traditional natural rubber. The new material light conveyor belt would play a leading role in the national industry and improve the competitiveness in the national brand in the international market.

Research Progress in Polypropylene/Nano Silicon Dioxide Composites

2010, 24 (11): 11-14 ; DOI: 10.19491/j.issn.1001-9278.2010.11.003

Abstract ( 2020 )

This review was about polypropylene/nano-silicon dioxide composites with their preparation, compatibility, and toughening/reinforcing mechanism introduced. The preparation methods included in-situ polymerization, sol-gel, and ultrasonic procedure. The mechanism involved in toughening of polypropylene matrix by the nanoparticles included cracks/craze mutual transformation, physical chemistry process, and critical ligand thickness. The mechanical properties of the composites could be further increased through surface modification of the nano-particles to reduce the interface energy, increase the wetting and binding, and regulate its hydrophobicity.

Research Progress in Reactive Processes of Sulfonated Polystyrene

2010, 24 (11): 15-19 ; DOI: 10.19491/j.issn.1001-9278.2010.11.004

Abstract ( 2172 )

The research progress on preparation of sulfonated polystyrene (SPS) and synthesis of new fatty acid sulfonic acid resin was introduced. The common sulfonating agents included sulfuric acid, sulfur trioxide (SO3), and chlorosulfonic acid. When chlorosulfonic acid was used, the reaction time could be shortened from 3 h to about 30 min, the sulfonation degree of PS could be controlled, the post-treatment processing was simplified, and the amount of waste acid the cost of production could be largely reduced.

Structure and Properties of Glass Fiber Reinforced Isotactic Polypropylene Modified by β-nucleating Agent Under Flow Field

2010, 24 (11): 20-25 ; DOI: 10.19491/j.issn.1001-9278.2010.11.005

Abstract ( 2161 )

Isotactic polypropylene containing β-nucleating agent and glass fiber was prepared by conventional injection molding (CIM) and dynamic packing injection molding (DPIM), respectively. Molecular orientation of iPP, GF orientation, and crystallization behavior were characterized by wide angle X-ray diffraction (WAXD), scanning electronic microscopy (SEM), and small angle X-ray scattering (SAXS). It was found that the DPIM sample with 30 wt % GF and 0.2 wt % β-nucleating agent had the best mechanical properties, with the tensile strength achieved 58.52 MPa and the impact strength 9.26 kJ/m2. This could be attributed to the bamboo-like 'hard skin, soft core' bionic structure formed in the samples.

Study on Chemical Modification and Plasticization of Soy Protein Isolate

HU shi ming yongyan cui

2010, 24 (11): 26-30 ; DOI: 10.19491/j.issn.1001-9278.2010.11.006

Abstract ( 1670 )

The chemical modification of soybean protein with urea, sodium hydroxide, and methy1dichlorosi1ane and the plasticization of the modified soy protein isolate using glycerol, polyethylene glycol, sorbitol, caprolactam, and ethyl amide. The structure of modified soy protein isolate was characterized，and the thermal, mechanical, and rheological properties as well as water resistance of the modified soy protein isolate were studied. The long chain of protein could be cut effectively by alkali which increased the processability of protein. The hydrophilic group in the protein molecules could be reacted off or covered by urea and dimethyldichlorosilane, so the water resistance of the materials was increased. Polyethylene glycol and caprolactam were proven effective plasticizers.

Synthesis and Characterization of Hyperbranched Polyurethane

2010, 24 (11): 31-34 ; DOI: 10.19491/j.issn.1001-9278.2010.11.007

Abstract ( 2157 )

Hyperbranched polyurethanes (HBPU) from the third generation to the sixth generation were synthesized from 2,4-diisocyanatotoluene（TDI）and trimethylolpropane. The products were characterized using Fourier transform infrared spectroscopy（FTIR）, XRD, and differential scanning calorimetry（DSC）. It was found that the -NCO of TDI was reacted completely. The d-spacing from the third generation to the sixth generation were 0.41，0.46，0.475，0.414 nm, respectively. With the increasing generation, the glass transition temperature (Tg) decreased from 117.29 ℃ of the third generation to 69.14 ℃ of the sixth generation regularly. Blending 15 wt % of stearic acid modified HBPU(HUPU-SA) with liner PU, the tensile strength and enlongation at break of increased 4.1 and 4.2 times, respectively.

Research on Preparation and Properties of Plasticized and Toughened Polypropylene

ZHOU Zhong-Yu

2010, 24 (11): 35-38 ; DOI: 10.19491/j.issn.1001-9278.2010.11.008

Abstract ( 2218 )

Nano silicon dioxide (nano-SiO2) was dispersed into liquid paraffin(LP) forming a nano-sol, which was melt blended with PP using a twin-screw extruder resulting in PP composites. The effect of LP and nano-SiO2 content on mechanical properties and crystallization behavior of PP was investigated. By the plasticization and toughening of LP and nano-SiO2, the impact strength of PP composites was 280 % higher than that of neat PP. In addition, it was found that LP increased the crystallinity of PP and nano-SiO2 decreased the spherulite size.

Study on Crystallization Behavior of Polyethylene Terephthalate Bottle Chips

2010, 24 (11): 39-42 ; DOI: 10.19491/j.issn.1001-9278.2010.11.009

Abstract ( 1653 )

The crystalline behavior of two kinds of PET bottle chipswas studied using Fourier transform infra spectroscopy (FTIR), thermogravimetry (TG), hot-stage microscope, and differential scattering calorimetry (DSC). It showed that Chip#1 possessed higher crystallization rate and crystallinity than #2. The crystallization temperature of #2 was higher than that of #1.

Thermal Performance and Aging Properties of the PEB-g-MAN/SAN Blends Synthesized by Suspension Polymerization

2010, 24 (11): 43-48 ; DOI: 10.19491/j.issn.1001-9278.2010.11.010

Abstract ( 2108 )

PEB-g-MAN, synthesized by suspension grafting copolymerization of methyl methacrylate and acrylonitrile onto poly(ethene-co-1-butene) (PEB), was prepared to toughen styrene-acrylonitrile copolymer(SAN). Thermal performance and aging properties of the PEB-g-MAN/SAN blends were studied using DMA, TG/DTG, accelerated weathering aging, and thermal oxidative aging tests. DMA analysis showed that the differences of glass transition temperature (Tg) between PEB phrase and SAN phrase in PEB-g-MAN/SAN blends were apparently less than those between PEB elastomer and SAN resin, indicating PEB-g-MAN and SAN were partially compatible. TG/DTG results revealed that PEB-g-MAN/SAN blends performed better thermal stability than SAN resin. The aging test demonstrated the weatherability and yellowing resistance properties of PEB-g-MAN/SAN blends were much better than those of ABS. After thermal oxidation aging test, the retention of notched impact strength of PEB-g-MAN/SAN blends was superior to ABS, while the tensile strength and the flexural strength were slightly less than ABS.

Functionalization of Low-density Polyethylene with Maleic Anhydride Through Stress-induced Initiation and Its Effect on the Peeling Strength of Al/PET Composite Film

2010, 24 (11): 49-53 ; DOI: 10.19491/j.issn.1001-9278.2010.11.011

Abstract ( 1982 )

Low-density polyethylene (PE-LD) melt was grafted with maleic anhydride (MAH) in a twin-screw extruder in presence of an initiator. By enhancing the screw rotation speed, the chains of PE-LD were scissored forming macromolecular radicals, thus promoted the grafting reaction. When the screw rotation speed was 800 r/min, a high percentage of grafting（0.71 %）and a high melt flow rate (0.87 g/10 min), and a low gel content (<0.40 % ) could be obtained. The functionalized product of PE-LD was blended with EPDM and was used as a hot-melt adhesive. When the reaction temperature was 310 ℃, the screw rotation speed was 600 r/min, and the content of EPDM was 80 wt %, the bond strength of T-adhint of the Al/PET film reached 3.87 N/mm.

Study on Blends of PLA∕Elastomers

Huang-Jin

2010, 24 (11): 54-57 ; DOI: 10.19491/j.issn.1001-9278.2010.11.013

Abstract ( 1544 )

The microstructure, mechanical properties, and crystallization behavior of PLA/elastomer blends were studied in this paper. The compatibility between PLA and elastomer was not good, however, when the fraction of elastomer was 40 wt%, it could be finely dispersed into PLA matrix. In presence of elastomer, cold crystallization of PLA was observed 110 ℃. With increasing content of elastomer, the plasticizing time of the blends decreased, melt flow rate and the elongation at break increased rapidly, however, the tensile strength decreased.

Effect of Surface Treatment of SiC Nano-particles on Properties of PTFE/Nano SiC Composites

GU Hongyan

2010, 24 (11): 58-61 ; DOI: 10.19491/j.issn.1001-9278.2010.11.014

Abstract ( 1734 )

The mechanical and tribological properties of polytetrafluoroethylene (PTFE) composites filled with nano-SiC were studied. The effects of content and surface treatment of nano-SiC on the mechanical, friction, and wear properties of PTFE composites were investigated. The tensile fracture surfaces were observed by a scanning electron microscope (SEM). The strengthen mechanism for the composites was explored. It showed that the untreated nano-SiC increased the hardness and wear resistance of PTFE composites in varying degrees. The tensile strength, impact strength, and friction properties of composites were further improved with the nano-SiC being treated with a coupling agent. The surface treatment of nano-SiC resulted in a better interface combination with PTFE matrix and thus a finer dispersion.

Computer Simulation of Bubble-growth Process in PS/CO₂ Foaming System

2010, 24 (11): 62-67 ; DOI: 10.19491/j.issn.1001-9278.2010.11.015

Abstract ( 2072 )

Based polystyrene(PS)/CO2 foaming system, using cell model, three mathematical model for bubble growth were derived based on different constitutive equations: Newtonian fluid, power law fluid, and dewitt fluid. Comparing with experimental results, the effect of physical parameters such as melt elasticity and non-Newtonian nature on the bubble growth process was studied. It was showed that dewitt model was suitable for the bobble growth, the melt elasticity promoted the bobble growth in the early growth, the non-Newtonian behavior of the melt had effect in the whole bobble growth process.

Influence of Compatibilizer and Processing Technology on Morphology and Mechanical Properties of PA1010/PP Blends

2010, 24 (11): 68-71 ; DOI: 10.19491/j.issn.1001-9278.2010.11.017

Abstract ( 2111 )

Polypropylene (PP) was grafted with maleic anhydride (MAH) and styrene (St), the product [PP-g-(MAH-co-St)] was used as a compatibilizer of blends of PA1010 and PP. The influence of PP-g-(MAH-co-St) on the morphology and mechanical properties of PA1010/PP blends was studied. It was found that PP-g-(MAH-co-St) effectively improved the compatibility of PA1010 and PP, the mechanical properties of the blends was improved. The melt flow rate decreased, melt viscosity of the melt increased, and the size of dispersed phase PP reduced with increasing content of PP-g-(MAH-co-St). When the weight ratios of PA1010/PP/PP-g-(MAH-co-St) were 70/25/5 and 70/20/10, the tensile strength of blends increased 55.0 % and 61.9 %, the impact strength increased 61.0 % and 129.7 %, respectively, based on that of blend (PA1010/PP=70/30w). Melt fracture appeared when the shear rate was 706.5 s-1, which became serious when the shear rate was 5002.65 s-1.

Study on Extensional Rheology Properties of Polyethylene Using Melt Spinning Techniques

2010, 24 (11): 72-75 ; DOI: 10.19491/j.issn.1001-9278.2010.11.018

Abstract ( 1819 )

The extensional rheology properties of low-density polyethylene (PE-LD), linear low density polyethylene (PE-LLD), and high-density polyethylene (PE-HD) were studied in melt spinning process. It showed that both melt strength and extensional viscosity of PE-LD, PE-LLD, and PE-HD melt decreased with increasing temperature. With increasing extensional strain rate, both extensional stress and extensional viscosity of PE-LD, PE-LLD, and PE-HD melt decreased.

Effect of Processing Temperature on Gelation Degree and Mechanical Properties of CPVC

WANG Yan-fang

2010, 24 (11): 76-79 ; DOI: 10.19491/j.issn.1001-9278.2010.11.020

Abstract ( 2327 )

The gelation degree of CPVC in deferent processing temperatures were tested using DSC, and the relationship between the gelation degree and mechanical properties was studied. It showed that when the processing temperature increased from 170 to 180 ℃, the gelation degree increased from 47.2 % to 76.5 %. The CPVC exhibited good mechanical properties when the gelation degree was 61.9 %.

Numerical Simulation of the Cell Nucleation Location of WPC/Supercritical Fluid Composites

2010, 24 (11): 80-83 ; DOI: 10.19491/j.issn.1001-9278.2010.11.021

Abstract ( 1869 )

Flow field simulation of WPC/supercritical CO2(WPC/Sc-CO2) composites flowing through an extrusion foaming die with different die dimension were performed by FEM software Polyflow, and the effects of foaming die dimension on the cell nucleation of WPC/Sc-CO2 composites were investigated. It was found that increasing the capillary length of the foaming die had little effect on the pressure drop rate and the distance from cell nucleation point to die exit. By decreasing the capillary diameter of the foaming dies, a large pressure drop rate was created, and the cell nucleation point location moved toward the die exit.

Investigated on Thermal Degradation of Hexakis (phenoxy) Cyclotriphosphazene Flame Retarded Epoxy Resin

Rui WANG

2010, 24 (11): 84-88 ; DOI: 10.19491/j.issn.1001-9278.2010.11.022

Abstract ( 2212 )

Hexakis(phenoxy) cyclotriphosphazene (HPCP) was prepared using homemade hexachlorocyclotriphosphazene through nucleophilic substitution reaction. The prepared HPCP was introduced into epoxy resin (EP) as a flame retardant and the thermal degradation properties and mechanism were characterized by LOI and TG-MS. It showed that the char yield increased obviously by the addition of HPCP and the LOI of EP/HPCP system with 10 phr HPCP increased to 27.0 %. The flame retardancy could be explained as the results of N-P synergistic effect and release of H2O from the self-condensation of HPCP.

Study on Filled with Waste Epoxy Molding Compound

2010, 24 (11): 89-93 ; DOI: 10.19491/j.issn.1001-9278.2010.11.023

Abstract ( 1934 )

Waste epoxy molding compound (WEMC) powder was used as a filler to prepare PVC/WEMC composites by compression molding. The interfacial bonding between the filler and PVC matrix were studied. Effects of molding temperature and WEMC powder content on the mechanical and dynamic mechanical properties of the composites were investigated. It showed that WEMC powder had reactivity to graft onto polar resin PVC. When molding temperature was 200 ℃, content of WEMC was 60 wt %, the composites showed excellent mechanical properties, with tensile strength of 32.13 MPa, flexural strength of 60.70 MPa, and impact strength of 4.68 kJ/m2. With increasing WEMC powder content, the storage modulus of the composite improved, the loss factor peak moved to higher temperature area, and the shape of the peak became wider first then narrower.

Study on Double-flight Driving Theoretic Model for Helically Grooved Feed Single-screw Extruder

XUE Ping GuangLi Tang

2010, 24 (11): 95-99 ; DOI: 10.19491/j.issn.1001-9278.2010.11.024

Abstract ( 1563 )

Some helical grooves were cut on the inside of feeding sleeve, so that the barrel and the screw could be regarded as an integrated system to cooperatively convey the solid materials, thus a novel physical model known as "arc model" was formulated. At the same time, all the materials between the groove and channel were considered as a solid-plug, a novel solid conveying theory known as "double flight driving theory" was proposed, which filled out the flaw in the traditional extruder in the positive conveying. Finally, the boundary conditions in the crossover from friction drag to positive conveying and the design criterion of groove structure were given.