PC/ABS及PC/ABS/PE-g-MAH共混体系相容性的研究

研究了聚碳酸酯与ＡＢＳ（ＰＣ／ＡＢＳ）及ＰＣ／ＡＢＳ与马来酸酐接枝聚乙烯共聚物（ＰＣ／ＡＢＳ／ＰＥ－ｇ－ＭＡＨ）共混体系的力学性能和应力开裂性能。用ＤＳＣ和ＳＥＭ研究了共混体系的相容性。结果表明：ＡＢＳ的加入能提高ＰＣ的冲击强度,ＡＢＳ的含量及品种影响ＰＣ／ＡＢＳ合金的力学性能,ＡＢＳ能提高ＰＣ的耐溶剂应力开裂性能。ＰＣ／ＡＢＳ／ＰＥ－ｇ－ＭＡＨ共混体系的力学性能和相容性优于ＰＣ／ＡＢＳ共混体系,     

PC/ABS blends: Compatibilization and mechanical behaviour

PC/ABS(M) blends, encompassing the whole composition range between pure PC and ABS(M), were prepared by melt-mixing in a Brabender-like apparatus. Thermal, mechanical and impact tests were performed on compression moulded specimens. Inward Tg shifts were detected for PC and ABS(M) in the blends with respect to pure PC and ABS(M) values, indicating an interaction between the component domains. This finding was confirmed by the comparison of the experimental tensile moduli with the Kernels model predictions, showing an evidence of a good adhesion between the phases. A synergistic effect was observed for the impact strength as well as for the maximum stress at an ABS(M) blend content of about 25 weight %. All the results are interpreted on the basis of an interlayer existing at the boundary between the PC and ABS phases. A preliminary investigation on the influence of the ABS internal composition, keeping constant all the other conditions (mixing, processing, specimen preparation), was carried out as well. Differences in the properties of PC/ABS(M) and PC/ABS(B) blends are thoroughly discussed. The compatibility between PC and ABS domains seems to be scarcely influenced by such a parameter in these blends.     

The effect of different impact modifiers in halogen-free flame retarded polycarbonate blends - II. Fire behaviour

In this second of a series of two papers, the fire behaviour of halogen-free flame retarded polycarbonate (PC) blends with different impact modifiers was studied. The impact modifiers were acrylonitrile-butadiene-styrene (ABS), a poly(n-butyl acrylate) rubber (PBA) with a poly(methyl methacrylate) (PMMA) shell and two silicone-acrylate rubbers consisting of PBA with different amounts of polydimethylsiloxane (PDMS) and different shell materials (PMMA and styrene-acrylonitrile, SAN). The flame retardant was bisphenol A bis(diphenyl phosphate) (BDP). Flammability was determined by LOI and UL 94. The burning behaviour under forced flaming conditions was studied by cone calorimeter under different external irradiations and by pyrolysis combustion flow calorimeter measurements. The exchange of ABS with the pure acrylate rubber worsened flammability, while similar results were obtained in cone calorimeter measurements. The exchange of ABS with the silicone-acrylate rubbers is promising, particularly with higher amounts of PDMS. In flammability tests strongly enhanced LOI values were obtained and therefore silicone-acrylate rubbers look like promising alternatives for ABS.     

酸碱处理蒙脱土与磷酸酯阻燃剂复配阻燃PC/ABS合金

采用酸碱处理法对蒙脱土进行有机化改性, 再将酸碱处理的蒙脱土与磷酸酯阻燃剂复配, 作为聚碳酸酯/丙烯腈-丁二烯-苯乙烯三元共聚物(PC/ABS)合金的阻燃体系, 并表征了酸碱处理蒙脱土对合金的热稳定性和阻燃性能. 结果表明, 间苯二酚双(二苯基磷酸酯)改性的蒙脱土(BDP-MMT)使阻燃PC/ABS合金的起始分解温度降低, 而酸碱处理蒙脱土却使合金的起始分解温度有所提高; BDP-MMT的加入会恶化碳层的阻隔性能, 而酸碱处理蒙脱土却可以增加碳层的稳定性, 使第二热释放峰值出现的时间延迟, 且适合的酸浓度处理蒙脱土可以使合金通过UL-94 V-0级检验.     

The effect of different impact modifiers in halogen-free flame retarded polycarbonate blends - I. Pyrolysis

In this first of two papers, the thermal decomposition of bisphenol A bis(diphenyl phosphate)-flame retarded polycarbonate (PC) blends with different impact modifiers was studied. The impact modifiers were an acrylonitrile-butadiene-styrene (ABS), a poly(n-butyl acrylate) (PBA) rubber with a poly(methyl methacrylate) (PMMA) shell and two silicone-acrylate rubbers consisting of PBA with different amounts of polydimethylsiloxane (PDMS) and different shells (PMMA and styrene-acrylonitrile, SAN). The focus of this work was to study the impact of the acrylate and silicon-acrylate rubbers with respect to pyrolysis and flame retardancy in comparison to common ABS. Thermogravimetry (TG) was performed to investigate the pyrolysis behaviour and reaction kinetics. TG in combination with FTIR identified the pyrolysis gases. Solid residues were investigated by FTIR-ATR. PC/ABS shows two-step decomposition, with PC decomposing independently from ABS at higher temperatures. Pure acrylate rubber destabilises PC due to interactions between the rubber and PC, which leads to earlier decomposition of PC. Using silicone-acrylate rubbers led to similar results as PC/ABS with respect to pyrolysis, reaction kinetics and analysis of the solid residue; hence the exchange of ABS for the silicone-acrylate rubbers is possible.     

Synthesis and applications of biscyclic phosphorus flame retardants

The influence of structural effects of organo-phosphorus flame retardants (FRs) on their flame retardant action was investigated. A series of spirobisphosphorus compounds including 3,9-dibutyl-3,9-dioxo-2,4,8,10-tetraoxa-3,9-diphosphaspiro-5,5-undecane were prepared using various synthetic methods such as the Arbuzov reaction. The chemical structure of the product was confirmed by ¹H and ³¹P NMR. Thermogravimetric analysis (TGA) results reveal that these cyclic phosphorus compounds show a single step degradation in the range of 250-400 °C and act in the gas phase rather than in the condensed phase. The obtained products were blended with an acrylonitrile-butadiene-styrene copolymer (ABS) or polycarbonate (PC) and their flame retardant behavior was evaluated using a UL-94 vertical test. V-0 ratings are achieved at 15-35 wt% loading of FR for ABS and at a much lesser amount of loading for PC. In both cases, it is apparent that the flame retardancy is strongly dependent on the P content of the flame retardant.     

Investigation of polycarbonate/acrylonitrile butadiene styrene/multiwall carbon nanotube nanocomposites under impact loading

In this study, the effect of polycarbonate (PC)/acrylonitrile butadiene styrene (ABS)‐reinforced multiwall carbon nanotube (MWCNT) nanocomposites under a high‐velocity impact was investigated. PC/ABS (70/30 w/w)/MWCNT nanocomposites containing 1, 2, and 4 wt% were used to manufacture samples for this study. The samples were fabricated in sheet form with 100 × 100 mm dimensions and tested by gas gun for high‐velocity impact tests. The experimental results indicate that the energy absorption, limit velocity, and tensile modulus of the nanocomposite samples increased by approximately 121%, 52%, and 103% for the PC/ABS (70/30 w/w)/2 wt% MWCNT samples respectively. These results were confirmed by a transmission electron microscopy analysis test that was conducted for the state of dispersion of MWCNTs in the nanocomposite samples. The transmission electron microscopy results show that the best morphological structure of carbon nanotube at the interface of PC and ABS is that for the nanocomposite containing 2 wt% MWCNTs, which led to improved interface of the nanocomposites and higher mechanical properties. Copyright © 2016 John Wiley & Sons, Ltd.     

Comparison of the Effect of an Organoclay,Triphenylphosphate, and a Mixture of Both on the Degradation and Combustion Behaviour of PC/ABS Blends

Summary: Polycarbonate Acrylonitrile-Butadiene-Styrene blends (PC/ABS) with flame retardants Triphenyl Phosphate (TPP), nanoclay and their mixtures were prepared in a twin- screw extruder. The morphological properties were characterized by X-ray diffractometry (XRD) which showed the intercalated structure of nanoclay in the matrix. Thermal stability of the samples was studied using Thermogravimetric Analysis (TGA), and the degradation kinetic parameters were determined using various methods including Kissinger, Flynn-Wall-Ozawa and Coats-Redfern methods. It was found that the sample containing both TPP and nanoclay has the highest activation energy. The activation energy order of PC/ABS blends with different flame retardant packages, obtained by Kissinger method agrees well with that obtained by Coats-Redfern. Cone calorimetry and limited oxygen index (LOI)/underwriters laboratory 94 (UL94) methods were used to investigate the fire behaviour and flammability of materials. The reduced mass loss rate (MLR), peak heat release rate (PHRR) and enhanced LOI of the composite containing mixture system confirmed a synergistic effect of TPP and nanoclay.     

Flame retardancy mechanisms of phosphorus‐containing polyhedral oligomeric silsesquioxane (DOPO‐POSS) in polycarbonate/acrylonitrile‐butadiene‐styrene blends

The flame retardancy mechanisms of a novel polyhedral oligomeric silsesquioxane containing 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO‐POSS) in polycarbonate/acrylonitrile‐butadiene‐styrene (PC/ABS) blends are discussed. The thermal stability of PC/ABS composites with different DOPO‐POSS loadings are investigated by TGA and the enhancement of the thermal stability could be found at high temperature range. Their fire behavior is tested by the LOI, UL‐94, and cone calorimeter. Excellent flame retardancy of PC/ABS composites have been discovered with 10 wt% DOPO‐POSS loading. TGA‐FTIR, FTIR, XPS, and SEM, respectively, are used to characterize the gaseous products and the condensed residue in thermal decomposition, and the micro‐structure of the chars from cone calorimeter tests. The decomposition of PC/ABS with 10 wt% DOPO‐POSS shows significant changes compared with PC/ABS by TGA, FTIR, TGA‐FTIR, and XPS analysis. The enhancement of the thermal‐oxidative stability of PC/ABS with DOPO‐POSS is attributed to the interaction between DOPO‐POSS and PC/ABS at high temperature, which might be the key for improvement of the flame retardancy. Copyright © 2011 John Wiley & Sons, Ltd.     

Polymer blends: materials with versatile properties

During the last fifty years blending of dissimilar polymers has been a major path to tailor materials with new properties in industry. Especially in the area of engineering thermoplastic materials this approach has led to a significant number of large volume products, like Polyphenyleneether/High Impact Polystyrene‐blends (PPE/HIPS), Polycarbonate/Styrenics‐blends (PC/ABS), Polycarbonate/Polybutyleneterephthalate‐blends (PC/PBT) and Polyamide/Polyphenyleneether‐alloys (PA/PPE). The commercial success of these materials is mainly related to their unique combinations of properties, which enables their use in a multitude of applications.     

PC及PC/ABS共混物的疲劳裂纹扩展研究

研究了聚碳酸酯(PC)和PC/ABS高分子材料的疲劳裂纹扩展规律,利用改进柔度法测量其裂纹扩展速率,采用扫描电子显微镜(SEM)观察其断口形貌,分析疲劳裂纹扩展机理.在较大裂纹扩展速率(10-6～10-3mm/cycle)范围内,PC/ABS的疲劳裂纹扩展速率可以用Paris公式da/dN=9·5587×10-5(ΔK)2·88381来描述.高分子材料PC的疲劳裂纹扩展速率约为高分子材料PC/ABS的3倍.高分子材料PC/ABS疲劳裂纹面上的特征以韧窝为主,较低裂纹扩展速率对应较小的韧窝,较高裂纹扩展速率对应较大的韧窝.高分子材料PC疲劳裂纹面有明显的不连续裂纹扩展带,其裂纹面相对较平.     

异山梨醇型聚碳酸酯与ABS树脂共混体系的结构与性能研究

采用异山梨醇型聚碳酸酯(DB),与掺混型ABS熔融共混制备了具有不同聚丁二烯(PB)含量和丙烯腈(AN)含量的DB/掺混型ABS合金,并在考察掺混型ABS特征对合金结构与性能的影响的基础上,分别使用同种掺混型ABS以及各种商品化ABS树脂,比较了DB/ABS合金和双酚A型聚碳酸酯/ABS合金的性能及其变化规律.结果表明,对DB/掺混型ABS(70/30)合金而言,PB含量变化对于合金拉伸性能的影响明显大于AN含量变化所带来的影响,在PB含量为6.3 wt%条件下,各不同AN含量的合金体系均有最好的性能表现.PB含量和AN含量变化对合金分散相形态的影响与力学拉伸性能变化特征一致.DB/ABS合金体系均具有良好的热稳定性与热力学相容性,受AN含量和PB含量变化的影响较小,合金玻璃化转变温度与DB非常接近.以双酚A型聚碳酸酯为基础的聚碳酸酯(PC)/ABS合金及以异山梨醇型聚碳酸酯为基础的DB/ABS合金,在拉伸性能变化上均表现出完全相同的规律,且无论是采用掺混型ABS还是采用商品化ABS的体系,PC/ABS与DB/ABS合金在拉伸性能所反映出的规律也是基本一致的.     

Kinetics study of thermal oxidative degradation of ABS containing flame retardant components

The thermal oxidative degradation kinetics of pure acrylonitrile–butadiene–styrene (ABS) and the flame-retarded ABS materials with intumescent flame retardant (IFR) were investigated using Kissinger, Flynn–Wall–Ozawa, and Horowitz–Metzger methods. The results showed that the degradation of all samples included two stages, the activation energy at the first stage decreased by the incorporation of these flame retardant components, while increased at the second stage. The activation energy order of the flame-retarded ABS samples at stage 2 illustrates the relationship between the composition of IFRs and their flame retardancy, FR materials with appropriate acid agent/char former ratio has higher activation energy and better flame retardancy.     

Effect of cyclic loading on tensile properties of PC and PC/ABS

The effects of cyclic loading on tensile fracture properties of polycarbonate (PC) and the alloy of polycarbonate and acrylonitrile-butadiene-styrene (PC/ABS) are experimentally investigated in the paper. Two digital cameras are used to record simultaneously the tensile deformation of specimens and the large deformation and the necking process of these polymers are discussed. Two lateral contractions are not identical at the later tensile stages and the contraction ratios in each lateral direction are related with the tensile strains in axial direction on width and thickness surface. The curvature radiuses at the minimum section during necking process are shown. The volume increases during necking process and then decreases gradually. The yield stress and fracture stress of PC/ABS are lower than that of PC. The degradation of the fracture stress and fracture strain due to the application of cyclic loading is larger for PC than that for PC/ABS, and these can be used to explain qualitatively why PC has higher fatigue crack growth rate than PC/ABS.     

Influence of flame retardant additives on the processing characteristics and physical properties of ABS

Antimony trioxide (Sb₂O₃) is a common additive in flame retardant formulations and a study has been made to determine the effects of adding different grades into ABS polymer either alone or with commercial brominated materials bis(Tribromophenoxy)ethane (BTBPE) or Tetrabromobisphenol A (TBBA). The results consider mechanical, microscopical and flame retardant properties, and the effects of different Sb₂O₃ grades with average particle sizes of 0.1μm, 0.52μm and 1.31μm. The Sb₂O₃ was added at 4wt% loadings and the bromines at 20wt% loadings. Additions of different grades of antimony trioxide showed that standard grades (0.52 and 1.31μm) had a detrimental effect on impact and flexural properties when added at a 4wt% loading. The use of a new sub‐micron particle size product (0.1μm) had little effect on impact properties and only a slight detrimental effect on the flexural modulus and flexural strength when added to the ABS. Additions of either of the two brominated materials also caused a large drop in impact properties when added at 20wt% loadings. The addition of TBBA BA‐59P into ABS caused an increase in both flexural modulus and flexural strength which was contrary to expectations. When formulated with 4wt% 1.31μm Sb₂O₃ these bromine containing compounds suffered a further reduction in impact energies. Using the 0.1μm material improved both impact and flexural properties but impact values were still below those of unfilled ABS. The addition of the 0.1μm grade resulted in improvements in fire resistance as measured by the UL‐94 properties.     

Engineering polymer alloys by reactive extrusion

During the last fifty years blending of dissimilar polymers has been a major path to tailor materials with new properties in industry. Since most of the interesting polymer blends are immiscible, the different compatibilisation strategies have received a lot of attention. In the area of engineering plastics, reactive blending is usually used to compatibilise immiscible polymers. The most important polymer alloys prepared by reactive extrusion [Polycarbonate/Polybutyleneterephthalate-alloys (PC/PBT), Polyamide/Polyphenyleneether-alloys (PA/PPE), Styrenics/Polyamide-alloys (ABS/PA)] have already reached an interesting sales volume. The commercial success of these materials is mainly related to their unique combinations of properties, which enables their use in a multitude of applications.     

Solidification of non-halogen fire-retardant liquids by encapsulation within porous uniform PDVB microspheres for preparation of fire-retardant polymeric blends

Polystyrene/polydivinyl benzene (PS/PDVB) composite microspheres of narrow size distribution were prepared by a single-step swelling process of uniform PS microspheres with DVB and benzoyl peroxide, followed by polymerization of DVB within the microspheres. Dissolution of the PS template resulted in porous uniformly sized PDVB microspheres. New, solid, non-halogenated, fire-retardant composite microspheres of narrow size distribution were prepared by encapsulation of resorcinol bis (diphenyl phosphate) (RDP) within the pores of the PDVB microspheres. The encapsulation was performed by two different methods as follows: (1) vacuum and (2) heat/cool cycles. The loading capacity of the RDP into the PDVB particles was elucidated. PS/PDVB-RDP blends were prepared by mixing PS with the PDVB-RDP microspheres. Thermogravimetric analysis (TGA) illustrated that the thermal stability of the PS increases as the content (10–40 %) of the PDVB-RDP increased. Polycarbonate/poly(acrylonitrile-butadiene-styrene)/PDVB-RDP (PC/ABS/PDVB-RDP) blends were prepared by melting PC/ABS together with the PDVB-RDP microspheres at 250 °C and then pelleting it in an injection molding machine at 250 °C and 40 t. The improved thermal stability of the PC/ABS by blending it with PDVB-RDP was demonstrated by a vertical burn test on PC/ABS/PDVB-RDP bones.     

A novel intumescent flame retardant: Synthesis and application in ABS copolymer

A novel phosphorous-nitrogen structure containing intumescent flame retardant, poly(4,4-diaminodiphenyl methane spirocyclic pentaerythritol bisphosphonate) (PDSPB) was synthesized and characterized. Thermal stability and flammability properties of ABS/PDSPB composites were investigated by thermogravimetric analysis (TGA) and cone calorimeter test, respectively. The results showed that the addition of PDSPB enhanced the thermal stability and flame retardancy of ABS significantly. The weight of residues improved greatly with the addition of PDSPB. FTIR and SEM investigations revealed that the residual chars contain polyphosphoric or phosphoric acid, which plays an important role in the process of carbonization. The intumescent chars formed from PDSPB and ABS/PDSPB composites were intact, multicellular and strong. It is confirmed that the char structure was a critical factor for flame retardancy of ABS resin.     

Thermal decomposition of polymer mixtures of PVC,PET and ABS containing brominated flame retardant: Formation of chlorinated and brominated organic compounds

The thermal decomposition of various mixtures of acrylonitrile butadiene styrene copolymer (ABS), ABS containing brominated epoxy resin flame retardant and Sb₂O₃, poly(ethylene terephthalate) (PET) and poly(vinyl chloride) (PVC) has been studied in order to clarify the reactions between the components of mixed polymers. More than 40 halogen-containing molecules have been identified among the pyrolysis products of mixed samples. Brominated and chlorinated aromatic esters were detected from the mixtures containing PET and halogen-containing polymers. A series of chlorinated, brominated and mixed chlorinated and brominated phenols and bisphenol A molecules have been identified among the pyrolysis products of polymer mixtures containing flame retarded ABS and PVC. It was established that the decomposition rate curves (DTG) of the mixtures were not simple superpositions of the individual components indicating interactions between the decomposition reactions of the polymer components. The maximal rate of thermal decomposition of both ABS and PET decreases significantly if the mixture contains brominated epoxy flame retardant and Sb₂O₃ synergist. The dehydrochlorination rate of PVC is enhanced in the presence of ABS or PET.     

The synergistic effect of adjuvant on the intumescent flame-retardant ABS with a novel charring agent

A laboratory-made poly-N,N′-ethyleneterephthalamide (PETA) was used as a novel charring agent and it was combined with ammonium polyphosphate (APP) to prepare the intumescent flame retardant (IFR). For improving the flame retardant efficiency of IFR on acrylonitrile–butadiene–styrene copolymer (ABS), several adjuvant (Adj), such as zeolite 4A (4A), aluminum phosphinate (AlPi), organic montmorillonite, and 2,2′-bis(2-oxazoline), was added, and the synergistic effect was investigated by the limiting oxygen index (LOI), the UL-94 (vertical flame) test, the thermogravimetric analysis (TG), and the scanning electron microscopy (SEM). The results showed that the LOI values of ABS/IFR/Adj (70/30/2) system exceeded 30, and they passed the V-0 rating in the UL-94 test. The TG data demonstrated that the thermal stability and the mass residue of ABS/IFR/Adj were effectively enhanced. Besides, the SEM indicated that adjuvant promoted the formation of the compact, uniform, dense, and intumescent charred layer after burning. After that, the synergistic effect of AlPi and 4A on APP/PETA was investigated by Thermogravimetry-Fourier transform infrared spectroscopy.