Phase volume and size effects on the terminal relaxation of ABS melts

The dynamical viscoelasticity of ABS melts with different particle size was investigated at various levels of rubbery phase contents. The effects of the rubber are more pronounced in the terminal zone: a transition from viscoelastic liquid to viscoelastic solid behavior was observed which can be interpreted as a physical gelation occurring at a critical rubbery phase content. This critical content resulted in being smaller in the case of smaller particles. A quantitative explanation of the experimental findings was proposed in terms of the average interparticle distance and overlapping of the chains grafted onto the neighboring rubber particles. The gel-like transition appeared to correspond to an approximately constant level of grafted chains overlapping.Presented in part at the Symposium Recent Developments in Structured Continua, Montreal (Canada), 26–28 May 1993.     

微波消解ICP-AES法测定ABS中Pb、Cd、Hg

以ABS塑料为研究对象，采用微波消解法进行样品的前处理，使用电感耦合等离子体发射光谱法测定ABS塑料中Pb、Cd、Hg，结果表明，Pb、Cd、Hg加标回收率均在95~105%之间，测试精密度均小于3%，该方法在缩短样品前处理时间的同时得到较高的元素消解回收率和较为理想的精确度，适用于ABS塑料中重金属含量的快速测定。     

Rational solutions to Q3δ in the Adler-Bobenko-Suris list and degenerations

We derive rational solutions in Casoratian form for the Nijhoff-Quispel-Capel (NQC) equation by using the lattice potential Korteweg-de Vries (lpKdV) equation and two Miura transformations between the lpKdV and the lattice potential modified KdV (lpmKdV) and the NQC equation. This allows us to present rational solutions for the whole Adler-Bobenko-Suris (ABS) list except Q4. The known Miura transformation for soliton solutions between the NQC equation and Q3_δ and the known degenerations for solitons from Q3_δ to Q2, Q1_δ, H3_δ, H2 and H1 in the ABS list are used. We show that the Miura transformation and degenerations are valid as well for rational solutions which are usually considered as “long-wave-limit” of solitons. All the rational solutions can be expressed in terms of {z _j} which are linear functions of (n, m).     

Investigation of tensile deformation behavior of PC,ABS, and PC/ABS blends from low to high strain rates

This paper experimentally studies the tensile deformation behavior of polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), and PC/ABS blends (with the blending ratios of PC to ABS being 80:20, 60:40, 50:50, and 40:60) from low to high strain rates. Using the universal MTS-810 machine and the split Hopkinson tension bar (SHTB) testing system, the quasi-static and impact tension tests are carried out at the room temperature. The curves of the true stress and the true strain are obtained. The deformation behaviors of PC, ABS, and PC/ABS blends are characterized in detail. The linear relationship between the strain rate and the yielding stress is given.     

Fuel oil from ABS using a tandem PEG-enhanced denitrogenation-pyrolysis method: Thermal degradation of denitrogenated ABS

Thermal degradation of ABS and denitrogenated ABS samples (DABS), prepared by sequential hydrolysis of ABS using PEG/NaOH, has been investigated under inert gas and at atmospheric pressure in a temperature range between 40 and 700 °C, by means of TGA, TGA-IR, and TGA-MS, to study the link between original structure of DABS and eventual pyrolysis. For DABS, thermal decomposition begins at the side groups of -CONH₂ and/or -COOH, resulting in a lower initial degradation temperature of DABS (around 330 °C) relative to ABS (372.5 °C). Moreover, less HCN and acrylonitrile evolve from the DABS samples, while the evolution of CO₂ starts earlier and becomes more important, in line with the decreased number of -CN groups and the increased number of -COOH functional groups due to hydrolysis. The results from thermo-analytical experiments were confirmed by batch pyrolysis tests: the nitrogen content of oil produced from DABS pyrolysis is much lower, compared with that from ABS, proving that effective denitrogenation of ABS prior to pyrolysis is beneficial to the quality of pyrolysis oil.     

EMI shielding and dynamic mechanical analysis of graphene oxide-carbon nanotube-acrylonitrile butadiene styrene hybrid composites

Carbon nanomaterials such as carbon nanotubes (CNTs), graphene and their hybrid have been studied extensively. Despite having excellent properties of CNTs and graphene have not yet been fully realized in the polymer composites. During fabrication agglomeration of CNTs and restacking of graphene is a serious concern that results in the degradation of properties of nanomaterials into the final composites. To improve the dispersion of CNTs and restacking graphene, in the present research work, we focused on the hybridization of graphene oxide and CNTs. Multiwalled carbon nanotubes (MWCNTs), functionalized carbon nanotubes (FCNTs), and graphene oxide-carbon nanotubes (GCNTs) reinforced acrylonitrile butadiene styrene (ABS) composites were prepared separately by vacuum filtration followed by hot compression molding. Further, dynamic mechanical analysis (DMA), and electromagnetic interference (EMI) shielding properties of ABS composites reinforced carbon nanofillers were investigated. The dynamic mechanical properties of polymers strongly depend on the adhesion of fillers and polymer, entanglement density of polymer chains in the presence of carbon fillers. The dynamic mechanical characteristics such as storage, loss modulus, and damping factor of prepared composites were significantly affected by the incorporation of MWCNTs, FCNTs, and GCNTs. Maximum EMI shielding effectiveness of −49.6 dB was achieved for GCNT-ABS composites which were highest compared to MWCNTs-ABS composites (−38.6 dB) and FCNTs-ABS composites (−36.7 dB) in the Ku band (12.4–18 GHz). These results depict the great potential of GCNTs-ABS composites to be used in various applications of efficient heat dissipative EMI shielding materials for electronic devices.     

Influence of fused deposition modeling parameters on the mechanical properties of ABS parts

This work aims to determine the influence of fused deposition modeling (FDM) printing parameters on the mechanical properties of parts fabricated on an Ultimaker2 printer with acrylonitrile butadiene styrene (ABS). The effect of several parameters such as interlayer cooling time (ILCT), nozzle diameter, infill density, raster angle and layer thickness on the ultimate tensile strength, yield strength, and elastic modulus of produced parts was evaluated. Two independent studies were conducted: a first study dedicated to the ILCT and a second study where the influence of other parameters was evaluated through a design of experiments (DoE) approach. Both studies were carried out through the execution of standard tensile tests. The statistical analysis of tensile tests results was processed with the ANOVA methodology. The obtained results indicate that a reduced ILCT improves the tensile strength of parts. It is shown that nozzle diameter and infill density are the parameters that most influence the mechanical properties of ABS, with the upper range selected values improving the studied mechanical properties. The raster angle configuration of (?45^o/45^o) benefits UTS and yield strength of ABS samples. Interactions of nozzle diameter on layer thickness were detected. It was observed that smaller layer thickness promotes a higher elastic modulus and UTS; however, for thinner layers (0.06‐0.10 mm), no significant differences were found on strength of samples due to potential high distortion levels.     

Improvement in toughness of poly(l-lactide) (PLLA) through reactive blending with acrylonitrile-butadiene-styrene copolymer (ABS): Morphology and properties

Poly(l-lactide) (PLLA) was melt-blended with acrylonitrile-butadiene-styrene copolymer (ABS) with the aim of enhancing impact strength and elongation at break of PLLA, but not sacrificing its modulus and stiffness significantly. However, PLLA and ABS were found to be thermodynamically immiscible by simply melt blending and the formed blends show deteriorated mechanical properties. The reactive styrene/acrylonitrile/glycidyl methacrylate copolymer (SAN-GMA) by incorporating with ethyltriphenyl phosphonium bromide (ETPB) as the catalyst was used as the in situ compatibilizer for PLLA/ABS blends to improve the compatibility between PLLA and ABS. The reactive process during melt blending was investigated by Fourier transformed infra-red (FTIR). It showed that the epoxide group of SAN-GMA reacted with PLLA end groups under the mixing conditions and that the addition of ETPB accelerated the reaction. Phase structure and physical properties of the compatibilized blends were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic mechanical analysis (DMA), tensile tests and impact property measurements. It was found that the size of ABS domains in PLLA matrix is significantly decreased by addition of the reactive compatibilizer. The dynamic mechanical analysis revealed markedly shifted glass transition temperatures for both PLLA and ABS, indicating the improved compatibility between PLLA and ABS. The mechanical tests showed the compatibilized PLLA/ABS blends had a very nice stiffness-toughness balance, i.e., the improved impact strength and the elongation at break with a slightly loss in the modulus.     

SMA、OMMT对PA6/ABS共混物聚集态结构及性能影响的研究

采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)等手段研究了苯乙烯-马来酸酐共聚物(SMA)、有机蒙脱土(OMMT)对尼龙6(PA6)/丙烯腈-丁二烯-苯乙烯(ABS)共混物体系聚集态结构及性能的影响.结果表明,SMA与OMMT的加入均可提高PA6/ABS共混物体系的强度及模量,但加入OMMT后共混物的韧性有所下降,而PA6/ABS/SMA共混物的韧性随SMA含量的增加呈上升趋势.SMA、OMMT对PA6/ABS共混体系都有细化ABS分散相的作用,随SMA加入量的增加,ABS分散相尺寸逐渐减小,分布趋于均匀;当OMMT加入量在4 phr以内时,对ABS分散相粒径影响不大,超过4 phr后,随着OMMT含量的增加,ABS分散相的尺寸逐渐减小.XRD与TEM的分析结果表明,对PA6/OMMT(100/5)共混物,OMMT主要以剥离形态分布,同时也存在少量OMMT聚集体;PA6/ABS/OMMT共混物中OMMT则基本以剥离形态选择分布在PA6基体相中.     

Processing and properties of engineering plastics recycled from waste electrical and electronic equipment (WEEE)

The characteristics of engineering plastics used in the preparation of electrical and electronic equipment were studied. More specifically, their thermal response was recorded by DSC experiments, the rheological properties were investigated via MFI tests and the mechanical properties were evaluated with tensile tests. The aim was to establish a procedure for recycling the same engineering plastics deriving from waste of electrical and electronic equipment (WEEE), which offers the additional advantage of using the as-received waste stream as a recyclable mixture, i.e. without sorting and classification of its components.The experimental results showed that blends of PC with ABS or ABS/HIPS can be prepared by direct mixing and this, would allow easy handling of the engineering plastics coming from WEEE, i.e. blending without the need of sorting. These mixtures can be easily processed and display acceptable mechanical properties with reasonable cost. Therefore, the processing characteristics and properties of the systems studied in this work could be the key for the design of an interesting approach for handling solid plastic waste from electrical and electronic devices.