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2013, Volume 27 Issue 11 Publication date: 26 November 2013 Previous Issue Next Issue

Study on Toughening of Polyvinylchloride with Nanoparticles

2013, 27 (11): 1-7; DOI: 10.19491/j.issn.1001-9278.2013.11.001

Abstract ( 352 ) PDF (0 KB)( 57 )

This paper summarized the application of nanoparticles in toughening and modification of PVC, elaborated the application of nanoCaCO3, nanoSiO2, nanoclay, and coreshell nanoparticles in PVC toughening. Research results showed that these nanoparticles were able to improve toughness and strength of PVC simultaneously. Besides, developing low price of nanoparticles was necessary.

Development and Countermeasures of Polymeric Composites for Automobiles

2013, 27 (11): 8-17; DOI: 10.19491/j.issn.1001-9278.2013.11.002

Abstract ( 306 ) PDF (0 KB)( 64 )

Based on different performance requirements of the automotive interior, exterior panels, and the main bearing structures in different parts, the current vehicle application of polymer composite materials was reviewed. The advantages and shortcomings in environmental protection, energy conservation of lightweight, low cost fabrication, and service security of automotive polymer composites were analyzed completely. The prospect of development trend were introduced.

Research Progress in Environmentally Friendly Flame Retardants

2013, 27 (11): 18-22; DOI: 10.19491/j.issn.1001-9278.2013.11.003

Abstract ( 370 ) PDF (0 KB)( 56 )

The production and application of flame retardants in China were reviewed, and the existing problems in this area were also analyzed. The classification，mechanism，research, and development of environmentally friendly flame retardants were introduced. The approaches to enhance the flame retardant efficiency of intumescent flame retardants were also discussed, including synergistic technology, surface modification, and microencapsulation. In the end, the future development of intumescent flame retardants was forecast.

Performace of Flame Retardant EVA/NBR Composites Reinforced by Attapulgites

2013, 27 (11): 23-27; DOI: 10.19491/j.issn.1001-9278.2013.11.004

Abstract ( 418 ) PDF (0 KB)( 69 )

EVA/NBR/FR composites containing magnesium hydroxide (MH) and red phosphorus (RP) as flame retardants were prepared. Attapulgite (AT) was used to improve the mechanical properties, oil resistance, flammability, and thermal stability of the composites. It showed that upon introductiing 10 phr AT, the tensile strength and elongation at break reached 10.4 MPa and 627.1 %, respectively. The mass was increased only 3.4　% after oil immersed at 40 ℃ for 72 hours; the limited oxygen index value reached 32.2, and UL 94 level was improved from no rating to V0; the residual char was increased from 29.3 % to 35.6 % in TG at 700 ℃. The morphology of cryogenically fractured surface before and after oil immersion were observed using SEM. It was found that the fractured surfaces became more compact after the addition of AT.

Study on Morphology and Properties of TDE85 Epoxy Resin/Polyether Sulfone Composite Systems

2013, 27 (11): 28-33; DOI: 10.19491/j.issn.1001-9278.2013.11.005

Abstract ( 432 ) PDF (0 KB)( 73 )

Epoxy resin was toughened using polyether sulfone(PES) forming TDE85/PES composite systems. The effect of PES on the thermomechanical properties of the composite was studied using SEM,DMA,DSC, and FTIR. It showed that the mechanical strength and glass transition temperature (Tg) of the epoxy resin was improved obviously by adding PES. When the mass content of PES was 8.00 %, the tensile strength, elongation at break, and impact strength of TDE85/PES composites were increased by 20.60 %, 29.29 %, and 44.20 %, respectively. Micromorphological study showed that the TDE85/PES system possessed a two phase structure. The deformed PES particles were dispersed in the epoxy resin matrix. The toughening effect of PES was caused by the formation of an SIPN in TDE85/PES system, and the deformed PES particles in the epoxy matrix under high stresses.

Preparation and Performance of Basalt Fiber Reinforced PVDF/PP/PETG Blends

2013, 27 (11): 34-38; DOI: 10.19491/j.issn.1001-9278.2013.11.006

Abstract ( 524 ) PDF (0 KB)( 73 )

PVDF/PP/PETG/basalt fiber composites were prepared by a melting blending method. The rheological behavior, morphology, mechanical properties, and heat resistance of the blends were investigated using rotary rheometer，scanning electron microscopy, material testing machine, and Vicat softening point machine in detail. It was found that PP, PVDF and PETG were pairwise immiscible, in which PP and PVDF formed a bicontinuoud phase and PETG presented in the system as spherulite particles. The poor mechanical properties of PVDF/PP/PETG blends were improved after basalt fiber was introduced. The tensile strength and flexural strength of PVDF/PP/PETG composite increased to 21.9 MPa and 44 MPa when the content of basalt fiber was 30 wt%. Vicat softening point of PVDF/PP/PETG composite was increased from 126.7 ℃ to 141.7 ℃.

Preparation and Characterizations of Polypropylene Composites Reinforced with Cotton Bast Fibers Treated by Acetic Anhydride

2013, 27 (11): 39-41; DOI: 10.19491/j.issn.1001-9278.2013.11.007

Abstract ( 325 ) PDF (0 KB)( 58 )

Cotton bast fiber treated with acetic anhydride was used as a reinforcer of polypropylene forming composite sheet of 4 mm thick， when the content of cotton bast fiber was 30 wt%. The cotton bast fiber was treated in a NaOH solution, and subsequently in a bath of acetic anhydride for 30 min at 30 ℃. The composite sheet acquired excellent tensile and bend strengths， increased by 6.33 % and 11.72 %, respectively.

Mechanical Properties and Behavior of Melt Crystallization of PTFE/Nano-AlN Composites

2013, 27 (11): 42-47; DOI: 10.19491/j.issn.1001-9278.2013.11.008

Abstract ( 341 ) PDF (0 KB)( 67 )

PTFE/nanoAlN composites were prepared by cold moulding and sintering in air. Effects of nanoAlN content on the mechanical properties and crystallization of the composites were studied. It showed that mechanical properties and the degree of crystallization of composites first increased and then decreased with increasing weight percentage of nanoAlN. The nanoAlN exhibited a remarkable heterogeneous nucleation activity and the crystallization rate was enhanced. However, the effect of nanoAlN content on the crystallization temperature was not obvious.

Preparation of Epoxy Resin Microcapsules Coated with Polysulfone

2013, 27 (11): 48-53; DOI: 10.19491/j.issn.1001-9278.2013.11.009

Abstract ( 358 ) PDF (0 KB)( 82 )

Microcapsules with polysulfone (PSF) as the shell material and bisphenyl A epoxy resin as the core substance were fabricated by solvent evaporation method. The size distribution, surface morphology, and thermal properties of the microcapsules were investigated by means of laser particle size analyzer, optical microscope, and microcomputer differential thermal balance. Meanwhile, the influence of kind and dosage of dispersants, stirring rate, reaction temperature, and the mass ratio of wall to core materials on the preparation of microcapsules were discussed. It showed that higher reaction temperature was not beneficial to the encapsulation. When the concentration of PVA as the dispersion agent was 1.0 wt %, the stirring rate was 750 r/min, the reaction temperature was about 30 ℃, and the ratio of wall/core mass ratio was 2∶1, the microcapsules had an average diameter less than 100 μm, and were endowed with excellent sphericity and high yields.

Experimental Investigation of Tribological Properties of PE-UHMW Affected by Pressure and Velocity

2013, 27 (11): 54-58; DOI: 10.19491/j.issn.1001-9278.2013.11.010

Abstract ( 344 ) PDF (0 KB)( 74 )

The effect parameters on tribological properties of PEUHMW when used in shoe lining of the elevator system were studied. On an MMW1A frictional rig, under the condition of minimum oil supply, at same pressurevelocity product (PV) and temperature, the friction coefficient between PEUHMW and 45# steel and the mass loss of PEUHMW were measured. With increasing wearing time, the friction coefficient first declined sharply, then became stable; the temperature increased first sharply and then slowly. The mass loss of PEUHMW was zero during the whole experiment. For the same PV product value, both friction coefficient and temperature fluctuated，however, the amplitude of fluctuating became smaller with increasing pressure.

Effect of Different PETG on the Morphology Structure of PS/PETG Blends

2013, 27 (11): 59-65; DOI: 10.19491/j.issn.1001-9278.2013.11.011

Abstract ( 574 ) PDF (0 KB)( 60 )

Polystyrene/poly(ethylene terephthalate-co-1,4-cyclohexane dimethanol terephthalate) (PS/PETG) blends and PS/modified PETG blends were prepared by torque rheometer. The rheological properties of PS,PETG,and modified PETG were tested by using rotational rheometer and melt flow rate tester；the morphology structure of blends were investigated by using scanning electron microscope. The result showed that average particle size of PETG in PS/PETG blends and modified PETG in PS/modified PETG blends were increased with the PETG and modified PETG content increasing, the particle density showed crosscurrent; when the content of modified PETG and PETG was the same,the average particle size of modified PETG was high than the PETG,and the particle density of modified PETG was less than PETG，the particle size distribution of modified PETG was narrow.

Mechanical Behavior of PMMA Above the Glass Transition Temperature Under Uniaxial Compression

2013, 27 (11): 66-70; DOI: 10.19491/j.issn.1001-9278.2013.11.012

Abstract ( 436 ) PDF (0 KB)( 60 )

The uniaxial compression behavior of amorphous polymethylmethacrylate (PMMA) was studied between 110 ℃ and 130 ℃. It showed that PMMA was sensitive to the temperature, its yield stress decreased with increasing temperature. When the temperature was higher than 120 ℃,the yield peak disappears, showing good plasticity. PMMA was also sensitive to the strainrate. The strain hardening was gentle when the rate was ranging from 0.1 s-1 to 0.001 s-1. The microscopic mechanism above temperature and stressstrain dependent behavior was explained.

Effect of Cooling Rate and Pressure on PVT Relationships of Polymers

2013, 27 (11): 71-74; DOI: 10.19491/j.issn.1001-9278.2013.11.013

Abstract ( 299 ) PDF (0 KB)( 62 )

No matter how the process of polymer materials changed, the pressurevolumetemperature (PVT) of polymer materials always follows a special law. This paper innovatively developed a device for measuring pressure, cooling rate and other parameters through directly pressing test using a high cooling rate. The temperature transition point was reduced when the cooling rate increased. And it was increased when the pressure elevated.

Processing Parameter Optimization of Precision Injection Molding for Complex and Thickwall Automotive Parts

2013, 27 (11): 75-79; DOI: 10.19491/j.issn.1001-9278.2013.11.014

Abstract ( 312 ) PDF (0 KB)( 74 )

A high adaptable optimization model of volume shrinkage response surface was formulated with minimum volume shrinkage of plastic parts as the optimization goal, mold temperature, packing time, packing pressure, and melt temperature as the optimal variables. Using Box(Boxbehnken design) secondorder response surface design method, combine variance analysis, optimal process parameters were obtained. CAE analysis and prototyping experiments confirmed that these optimal parameters could decrease contraction by 8 %.

Effect of Talc on the Crystallization Properties and Mechanical Properties of PP/POE Blends

2013, 27 (11): 80-83; DOI: 10.19491/j.issn.1001-9278.2013.11.015

Abstract ( 481 ) PDF (0 KB)( 71 )

Homo-polypropylene/polyolefin elastomer blends (PPH/POE) and PPH/POE/talc composites were prepared by twins-screw extruder. The crystallization behavior and mechanical property of the blends and composites were studied. The results showed that the mechanical property of PPH was affected by adding POE. The impact strength of PPH/POE blends increased by the increasing POE content. However, the tensile strength was decreased. The impact strength increased from 2.1 kJ/m2 to 39 kJ/m2, and the tensile strength was decreased from 30 MPa to 22MPa, when the POE content was 20 %. The tensile strength can be improved when adding the talc, the tensile strength can reach 24 MPa when the talc content was 1 phr. Besides, the crystallization behavior of PP was not greatly affected by the inducing of POE. With the increasing POE content, the crystallinity of PP obviously decreased.

Synthesis of DOPO-FR and Performance of Flame Retardant Polyurethane Foams

2013, 27 (11): 84-88; DOI: 10.19491/j.issn.1001-9278.2013.11.016

Abstract ( 462 ) PDF (0 KB)( 63 )

A novel flame retardant for polyurethane foam, DOPOFR was synthesized by the condensation of benzaldehyde with aniline and DOPO. Using above flame retardant and expandable graphite (EG), triethylphosphate and DOPOFR polyurethane foam was prepared. Chemical structure of DOPOFR was characterized with FTIR, 1HNMR spectra, and 31PNMR spectra. The thermal stability, flameretardant properties, and mechanical behavior of PUFs with different contents of DOPOFR were investigated by thermogravimetric analysis, limited oxygen index, and universal testing machine. It showed that DOPOFR could form more char when it was lighted and get excellent flame retardancy for PUFs. The 　limited oxygen index value reached 24.7 % with only 20 wt % of DOPOFR. The synergistic effect among EG, triethylphosphate, and DOPOFR could further increase the limited oxygen index to 32 %.

Process Parameter Optimizing and Mould Design for Variablediameter Tubes Based on Moldflow

2013, 27 (11): 89-94; DOI: 10.19491/j.issn.1001-9278.2013.11.017

Abstract ( 298 ) PDF (0 KB)( 87 )

The optimal gate quantity and location were obtained by a simulation using Moldflow software through a “filling, packing, cooling” scheme. A set of orthogonal experiments was carried out to obtain the optimal injection parameters for minimum warpage including melt temperature, packing time, packing pressure, filling time, and mold temperature. An injection mold was designed based on above simulation and orthogonal experiments and the quality of the parts was improved effectively.

Study on Twin-screw Devolatilization Extrusion Equipment and Process for Water-soluble Acrylic Resin

2013, 27 (11): 95-99; DOI: 10.19491/j.issn.1001-9278.2013.11.018

Abstract ( 410 ) PDF (0 KB)( 74 )

The usage and production process of watersoluble acrylic resin were reviewed, and the devolatilization process and equipment of this product were focused on. The development, devolatilization principle, merits, and main technical parameters of twin screw extruder used for devolatilization were analyzed. The design methods of heat transfer, vacuum degree, screw components were suggested.

Research of Residual Stress for Injection Parts Based on Moldflow

2013, 27 (11): 100-104; DOI: 10.19491/j.issn.1001-9278.2013.11.019

Abstract ( 419 ) PDF (0 KB)( 58 )

Residual stress has an important impact on the mechanical properties of injection parts. Through an analysis using Moldflow it was known that increasing melt and mold temperatures, lowering injection rate, reducing packing time, and packing pressure were beneficial to reduce the residual stress. Subsequent industrial hydrostatic test verified the numerical simulation results, and found that the residual stress was seriously influenced by the melt and mold temperatures, while less affected by packing pressure, packing time, and injection rate.