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2015, Volume 29 Issue 08 Publication date: 26 August 2015 Previous Issue Next Issue

Innovation and Prospect of Plastics Technologies Under Regulatory Governance

2015, 29 (08): 1-8 ; DOI: 10.19491/j.issn.1001-9278.2015.08.001

Abstract ( 442 )

In this paper, both health and environmental hazards of monomers and additives in plastics were summarized. The development of heavymetalfree and high molecular weight additives was reviewed. It was suggested that more attention should be paid to improve the synergistic effect of additives.

Research Progress of Extrusion Technology for Micro-nano Layer Films

2015, 29 (08): 9-16 ; DOI: 10.19491/j.issn.1001-9278.2015.08.002

Abstract ( 489 )

This paper introduced the research progress of micro-nano layer film extrusion technology and the property improvement from this technology, including mechanical, optical, barrier, and electrical properties. A basis was provided for future research of micro-nano laminated extrusion and development of new functional composite materials.

Research Advance of Low Dielectric Constant Polyimide Films

2015, 29 (08): 17-24 ; DOI: 10.19491/j.issn.1001-9278.2015.08.003

Abstract ( 496 )

This paper introduced the latest patent technologies for preparing low dielectric constant polyimide films, focusing on fluorine substituent, alicyclic moieties, the porous structure, inorganic hybrid materials and some problems on the main molecular design. The paper also summarized research and development trend of colorless transparent polyimide films in the future.

Research Development of Fully Biodegrade Poly(lactic acid)/Plant Fiber Composites

2015, 29 (08): 25-31 ; DOI: 10.19491/j.issn.1001-9278.2015.08.004

Abstract ( 846 )

The latest research achievements in poly(lactic acid)/plant fiber composites were reviewed in this paper. The impacts of the nature of plant fibers，surface modification methods，preparation，and degradation performance on the properties of the composites were also analyzed. Moreover，the development prospect of these composites was also presented.

Preparation of Poly(vinylidene fluoride)/Flake Graphite/Carbon Fiber Highly Thermal Conductivity of Composite Materials

2015, 29 (08): 32-37 ; DOI: 10.19491/j.issn.1001-9278.2015.08.005

Abstract ( 498 )

Composites with highly thermal conductivity and corrosion resistance were prepared using PVDF as matrix，with flake graphite and carbon fibers as the fillers by melt mixing. The influences of filler’s content and surface modification on the thermal performance and mechanical properties of the composite were investigated. It was found that with increasing content of flake graphite the thermal conductivity increased，while the mechanical properties decreased. Carbon fibers could also improve the mechanical properties, but decreased the thermal conductivity. The surface modification favored the mechanical properties and thermal conductivity. The thermal conductivity of the composite reached 11.43 W/(m·K), tensile strength 48 MPa, and tensile elongation break 11 %.

Effects of Ammonium Molybdate on Flame Retardancy, Smoke Suppression and Thermal Stability of EVA/NBR Composites

2015, 29 (08): 38-41 ; DOI: 10.19491/j.issn.1001-9278.2015.08.006

Abstract ( 476 )

Ammonium molybdate(AHM) was introduced into EVA/NBR composites as a flame retardant. Smoke density test, limiting oxygen index, UL-94 test, cone calorimeter, and thermal gravimetric analysis(TG) were used to characterize the smoke suppression, flammability, and thermal behavior of the EVA/NBR composites. The maximum smoke density was reduced to 59.5 % and smoke density rating was only 34.7. The results of fire tests showed that the sample containing 1.0 phr AHM had a limiting oxygen index value of 33.3 % with V-0 rating of UL 94 test, and the heat release rate was decreased from 302 to 241 kW/m2. TG result showed that the thermal stability was improved. The morphology of residue char after smoke density test was observed and analyzed by scanning electron microscope (SEM), and it was found that the surface of the composites containing AHM was more compact.

Effect of Triphenylphosphite on Crystallization Behavior of Poly(lactic acid)

2015, 29 (08): 42-47 ; DOI: 10.19491/j.issn.1001-9278.2015.08.007

Abstract ( 453 )

In this paper, the effect of triphenylphosphite(TPP) on the crystal morphology and crystallization process of poly(lactic acid)(PLA) was investigated using polarizing microscopy(PLM) and differential scanning calorimetry (DSC). The crystallization kinetics was analyzed by the method of Mo. It showed that, firstly, the addition of TPP didn’t change the crystal morphology of PLA, and the crystal geometry of TPP-PLA was still spherical. Then, TPP decreased the cold-crystallization temperature(Tcc) of PLA from 115.4 to 102.8 ℃，and increased the crystalline degree from 30.2 % to 34.9 %. Mo’s F(T) values of TPP-PLA decreased obviously.

Properties of Broadband Dielectric Spectroscopy(BDS) of Poly(vinylidene fluoride)

2015, 29 (08): 48-53 ; DOI: 10.19491/j.issn.1001-9278.2015.08.008

Abstract ( 464 )

In this paper, the structure of poly(vinylidene fluoride)(PVDF) was analyzed by X-ray diffraction(XRD) and Fourier transform infrared(FTIR). It was found that melt crystallized PVDF contained mainly α phases. The dielectric properties of PVDF were investigated by broadband dielectric spectroscopy(BDS) spanning 10-1~107 Hz and -100~100 ℃. There were relaxation peaks of α-PVDF at 40~100 ℃ originated from glass transition and δ-PVDF at -100~-50 ℃ originated from polarization behavior of molecular motion at amorphous regions.

Synthesis and Properties of Heat-resistant Polyurethane with Mixed-soft Segments

2015, 29 (08): 54-58 ; DOI: 10.19491/j.issn.1001-9278.2015.08.009

Abstract ( 361 )

A bi-soft-segment PUF was prepared from a mixture of polyether N303 and H303,and the latter was prepared from glycerol. The effect of the weight ratio of N303/H303 and SiO2 filler on the properties of PUF was investigated. The mechanical stability at higher temperature was tested. It was found that the compress modulus and impact strength of the bi-soft-segment PUF were higher than those of either single-soft-segment PUF. The compress modulus and impact strength increased first and then decreased as a function of H303 weight ratio and reached a maximum when the ratio of N303/H303 was 50∶50. Pre-mixed SiO2 played a role to improve the cell uniformity and stabilize mechanical properties at higher temperature.

Crystallization Behaviors and Properties of High Fluidity and High Impact Polypropylene

2015, 29 (08): 59-65 ; DOI: 10.19491/j.issn.1001-9278.2015.08.010

Abstract ( 406 )

The isothermal and non-isothermal crystallization behavior of special material PP(K9928), a kind of high fluidity and high impact polypropylene, had been investigated by differential scanning calorimetry(DSC), and a further comparison with a typical PP(K7726H) in domestic market had been made. The results indicate that the onset crystallization temperature of K9928 was 3~5 ℃ higher than the contrastive sample and the higher crystallization rate could be observed for K9928 at low cooling rate. However, the span from onset temperature to end temperature was wider when the cooling rate is higher than 50 ℃/min, which leaded to a longer crystallization duration. Impact resistance of K9928 depended on its more block copolymers with similar structure.

Modification of Propylene-ethylene Random Copolymer by Different β Nucleating Agents

2015, 29 (08): 66-70 ; DOI: 10.19491/j.issn.1001-9278.2015.08.011

Abstract ( 403 )

A self-made propylene-ethylene random copolymer (PPR) in our laboratory were modified by using three kinds of commercialized β nucleating agents: aromatic amide β nucleating agents NJ star NU-100 and TMB-5 and rare earth β nucleating agent GH-100. The relative β crystallinity was calculated by using differential scanning calorimetry (DSC). The study results showed that: with loading β nucleating agents, the effect of β Samples of a self-made propylene-ethylene random copolymer(PP-R) were prepared in present of three kinds of commercialized β nucleating agents: NJ star NU-100, TMB-5, and rare earth GH-100. The relative β crystallinity was calculated by using differential scanning calorimetry(DSC). All three β nucleating agents resulted in higher content of β form in PP-R, especially when the cooling rate was relatively low. The order in the nucleating efficiency forming β crystals was: NJ star NU-100>GH-100＞TMB-5.

Preparation of Superhydrophobic Surfaces Based on Epoxy Resin Coupled Nano-silica

2015, 29 (08): 71-76 ; DOI: 10.19491/j.issn.1001-9278.2015.08.012

Abstract ( 469 )

Micron scale rough structures of titanium alloy substrate were acquired by laser manufacturing. Nanoscale rough structures were prepared by painting epoxy acetone solution and silica suspension subsequently. Superhydrophobic duplex-treated film was fabricated by perfluorodecyltrichlorosilane self-assembled monolayers deposited on micro- nano structures. Surface profiler, scanning electron microscope, and contact angle measurement were used to analyze the surface properties, and wettability of the specimens. It showed that micro- nano structures by laser manufacturing and nano-silica play an important role in preparing superhydrophobic surfaces. Contact angles on duplex-treated film increased initially and then decreased with increasing concentration of silica suspension, and finally stabilized at around 150 °. The maximum contact angle of 159 ° was acquired when the concentration of silica suspension was 12.0 g/L.

Study on Low-temperature Heat-sealing Layer Performance of CPP Heat-sealing Films

2015, 29 (08): 77-81 ; DOI: 10.19491/j.issn.1001-9278.2015.08.013

Abstract ( 1429 )

Polypropylene, metallocene polyethylene(mPE), and slip agents were blended forming a heat sealing film through three-layer co-extruded casting. The effect of polypropylene, heat-sealing temperature, the thickness, and the cooling roll temperature of the film on heat-sealing properties of the film were investigated. When 40 parts of TF400 and 60 parts of SFC-750M were used in the heat-sealing layer, the cooling roll temperature was 22.6 ℃, the heat-sealing strength could reach 16.44 N/15 mm, and the initial heat-sealing temperature could be lowered to 105 ℃.

Degradation Behavior and Oxidation Products Analysis for High Density Polyethylene by Photo-oxidation Aging Based on Infrared Spectra Analysis

2015, 29 (08): 82-86 ; DOI: 10.19491/j.issn.1001-9278.2015.08.014

Abstract ( 425 )

This article studied the xenon aging characteristics of high density polyethylene(PE-HD) used as rotational-forming packaging cases by attenuated total reflection infrared spectroscopy(ATR-FTIR). The changes in carbonyl groups, hydroxyl groups, branching degree, chain scission degree, and unsaturation degree were monitored to determine the degradation behavior. The spectra were analyzed by using Lorentz method, and the mechanism of the forming of various oxides was explored. The absorbance of unsaturation degree showed a trend of increase, while the branching degree and chain scission degree increased rapidly during the whole aging time. In early aging, the chain scission was predominant, but branching was more noticeble during later aging. The ketone was the primary oxidation product and the carboxylic acid, aldehyde, ester, and lactone products increased rapidly in the early aging progress, then slowly to a stable value.

Study on Processing Technology of Extrusion and Drawing for Heat Shrinkable Polyethylene Sheets

2015, 29 (08): 87-90 ; DOI: 10.19491/j.issn.1001-9278.2015.08.015

Abstract ( 451 )

In the calendaring of PE sheet, effects of roller temperature, stretching rate, roller space, and stretching speed on shrinkage rate and cross-section dimension were studied. It showed that the stretching rate and the roller space had greater impact on the shrinkage rate, with higher shrinkage rate observed at higher stretching rate and short roller space. Roller temperature and stretching speed slightly impact shrinkage rate, with shrinkage rate slightly enhanced at higher roller temperature and stretching speed. The shrinkage rate was up to 78 % (10 min，120 ℃) at a roller temperature of 60 ℃, a stretching rate of 45 %, a roller space of 1.5 mm and a stretching speed of 2.4 m/min.

Study of Polyurethane Adhesives Made from Modified Castor oil-based Polyols

2015, 29 (08): 91-97; DOI: 10.19491/j.issn.1001-9278.2015.08.016

Abstract ( 110 )

Preparation of Blocked Polyfunctional Isocvanate and Its Application Used as Crosslinking and Foaming Agents in PA6 Extrusion Foaming#br#

XU Zhijuan, LIN Xuechun, LUO Chaoyun, XIAO Wangdong

2015, 29 (08): 98-102; DOI: 10.19491/j.issn.1001-9278.2015.08.017

Abstract ( 60 )

Effects of Engaging Direction on Mixing Capability in Extruders with Differential Unequal Twin Rotors

2015, 29 (08): 103-105 ; DOI: 10.19491/j.issn.1001-9278.2015.08.018

Abstract ( 322 )

Numerical simulation of melt flow between differential twin screw rotors and unequal barrel holes was carried out using Polyflow software. 88 % of the mixing index for 3∶1 differential rotors was ranged between 0.5 and 1, indicating a strong extensional flow field. The mixing behaviors of both counter-rotation and co-rotation were equally good. In the co-rotation cavity, the high-speed zone was wider, degree of in-uniformity was higher, viscosity-thinning more obvious, which was favorable for material exchange. In the counter-rotation cavity, pressure and shear rate were larger, which was favorable for establishing higher pressure.

Injection Mold Design of Battery Cover and Optimization of Forming Process Based on CAE

2015, 29 (08): 106-110 ; DOI: 10.19491/j.issn.1001-9278.2015.08.019

Abstract ( 530 )

Based on the analysis of the backboard digital audio player, an injection mold was designed. The calculation of gating system and cooling system was mainly introduced. The mold was designed for compact structure, working stability, easy manufacture, and high precision. It provided a reference value for the design of similar plastic injection molds.

Design of Injection Moulds for Player Backboards

2015, 29 (08): 111-114 ; DOI: 10.19491/j.issn.1001-9278.2015.08.020

Abstract ( 464 )

Based on the analysis of the backboard digital audio player, an injection mold was designed. The calculation of gating system and cooling system was mainly introduced. The mold was designed for compact structure, working stability, easy manufacture, and high precision. It provided a reference value for the design of similar plastic injection molds.