Thermal aging of bisphenol-A polycarbonate/acrylonitrile–butadiene–styrene blends

Thermal aging of immiscible bisphenol-A polycarbonate/acrylonitrile–butadiene–styrene (PC/ABS) blends containing 25, 60, and 75% PC and the PC and ABS blend components have been studied. Changes in Izod impact properties and dynamic mechanical spectra are reported following aging at 90, 110, and 130°C for times up to 1500 h. PC/ABS blends containing 60 and 75% PC were found to retain high impact performance following aging at elevated temperatures, compared to the PC blend component. Dynamic mechanical spectroscopy is an effective probe for investigating the structure–property changes occurring and the mechanisms of aging. For PC and ABS, the changes were mainly due to physical aging of the amorphous polymers when aged below the glass-transition temperature. For the PC/ABS blends, oxidative degradation additionally contributes to loss of toughness. Although structure–property changes are related to the behavior of the blend components, additional factors of potential importance for multiphase polymer–polymer systems have been identified, including a redistribution of stabilizers during the blend manufacture. © 1995 John Wiley & Sons, Inc.     

Boiling water aging of polycarbonate and polycarbonate/acrylonitrile–butadiene–styrene resin and polycarbonate/low‐density polyester blends

The effects of boiling water on the mechanical and thermal properties and morphologies of polycarbonate (PC), PC/acrylonitrile–butadiene–styrene resin (PC/ABS), and PC/low‐density polyester (PC/LDPE) blends (compositions of PC/ABS and PC/LDPE blends were 80/20) were studied. PC and the PC/ABS blend had a transition from ductile to brittle materials after boiling water aging. The PC/LDPE blend was more resistant to boiling water aging than PC and the PC/ABS blend. The thermal properties of glass‐transition temperature (T_g) and melting temperature (T_m) in PC and the blends were measured by DSC. The T_g of PC and PC in the PC/ABS and PC/LDPE blends decreased after aging. The T_g of the ABS component in the PC/ABS blend did not change after aging. The supersaturated water in PC clustered around impurities or air bubbles leading to the formation of microcracks, which was the primary reason for the ductile–brittle transition in PC, and the microcracks could not recover after PC was treated at 160°C for 6 h. The PC/ABS blend showed slightly higher resistance to boiling water than did PC. The highest resistance to boiling water of the PC/LDPE blend may be attributed to its special structural morphology. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 589–595, 2003     

Effect of antioxidants on properties and morphology of poly(acrylonitrile–butadiene–styrene)/polycarbonate blends

Poly(acrylonitrile–butadiene–styrene), polycarbonate (PC), and two types of antioxidants have been blended by an extruder twin screw. Notched Izod impact strength, tensile property, and melting flow index (MFI) were measured for the blends including different amounts of antioxidants, and morphology of the blends was investigated by scanning electron microscopy (SEM). The antioxidant action, especially on mechanical properties and the phase structure of the blends, has been studied for the undergraded samples. It was found that the phenolic antioxidant, tetrakis (3,5-di-tert-butyl-4-hydroxyhydrocinnamoyloxy-methyl) methane, C₇₃H₁₀₈O₁₂, whose commercial name is KY-7910, and phosphite antioxidant, triphenyl phosphite (TPP), (C₆H₅O)₃P, all decrease the Izod impact strength and tensile modulus of the blends and increase the elongation at break if a small amount of the antioxidants (such as less than 0.7%) was mixed into the blends. When the content of the antioxidants is increased, surpassing 0.7%, KY-7910 has little effect on impact property of the blends, but TPP made the Izod impact strength decrease and the MFI increase to a great degree. SEM results show that the two phases of ABS/PC with a weight ratio of 30/70 is cocontinuous; this structure is destroyed by addition of the two antioxidants, and in ABS/PC/antioxidants blends, the size of the ABS phase, as dispersion, does not change not much with increasing KY-7910 content, but becomes more scattered and greater with increasing content of TPP. These results are consistent with the mechanical tests. © 1994 John Wiley & Sons, Inc.     

Mechanical performance of ternary in situ polycarbonate/poly(acrylonitrile‐butadiene‐styrene)/liquid crystalline polymer composites

Ternary in situ polycarbonate (PC)/poly(acrylonitrile‐butadiene‐styrene) (ABS)/liquid crystalline polymer(LCP) composites were prepared by injection molding. The LCP used was a versatile Vectra A950, and the matrix of composite specimens was PC/ABS 60/40 by weight. Maleic anhydride (MA) copolymer and solid epoxy resin (bisphenol type‐A) were used as compatibilizers for these composites. The tensile, dynamic mechanical, impact, morphology, and thermal properties of the composites were studied. Tensile tests showed that the tensile strength of the PC/ABS/LCP composite in the longitudinal direction increased markedly with increasing LCP content. However, it decreased slowly with increasing LCP content in the transverse direction. The modulus of this composite in the longitudinal direction appeared to increase considerably with increasing LCP content, whereas the incorporation of LCP into PC/ABS blends had little effect on the modulus in the transverse direction. The impact tests revealed that the Izod impact strength of the composites in both longitudinal and transverse direction decreased with increasing LCP content up to 15 wt %; thereafter it increased slowly with increasing LCP. Dynamic mechanical analyses (DMA) and thermogravimetric measurements showed that the heat resistance and heat stability of the composites tended to increase with increasing LCP content. Scanning electron microscopy observation and DMA measurement indicated that the additions of epoxy and MA copolymer to PC/ABS matrix appeared to enhance the compatibility between the PC and ABS, and between the matrix and LCP. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2274–2282, 1999     

The vibration welding of poly(butylene terephthalate) and a polycarbonate/poly(butylene terephthalate) blend to each other and to other resins and blends

Vibration welding is used to assess the weldability of poly(butylene terephthalate) (PBT) and a polycarbonate/poly(butylene terephthalate) blend (PC/PBT) to each other and to other resins and blends: PBT to PC/PBT, PBT to modified poly(phenylene oxide) (M-PPO), PBT to polyetherimide (PEI) and PEI to a 65 wt% mineral-filled polyester blend (65-PF-PEB), PBT to a poly(phenylene oxide)/polyamide blend (PPO/PA), PC/PBT to M-PPO, and PC/PBT to PPO/PA. Based on the tensile strength of the weaker of the two materials in each pair, the following relative weld strengths have been demonstrated: PBT to PC/PBT,98%; PBT to PEI, 95%; 65-PF-PEB to PEI, 92%; and PC/PBT to M-PPO, 73%. PBT neither welds to M-PPO nor to PPO/PA, and PC/PBT does not weld to PPO/PA.     

Thermooxidative degradation of poly(vinyl chloride)/acrylonitrile–butadiene–styrene blends

The thermal degradation process of poly(vinyl chloride)/acrylonitrile–butadiene–styrene (PVC/ABS) blends was investigated by dynamic thermogravimetric analysis in the temperature range 50–650°C in air. The thermooxidative degradation of PVC/ABS blends of different composition takes place in three steps. In this multistep process of degradation the first step, dehydrochlorination, is the most rapid. The maximal rate of dehydrochlorination for the PVC blends containing up to 20% ABS-modifier is achieved at average conversions of 23.5–20.0%, i.e., at 13.5% for the 50/50 blend. The apparent activation energies (E = 103–116 kJ mol⁻¹) and preexponential factors (Z = 2.11 × 10⁹−3.45 × 10¹⁰min⁻¹) for the first step of the degradation process were calculated after the Kissinger method. © 1996 John Wiley © Sons, Inc.     

Effects of moisture absorption on fracture behaviors of acrylonitrile‐butadiene‐styrene resin

The effect of moisture absorption on fracture behaviors of acrylonitrile‐butadiene‐styrene (ABS) resin has been studied. For comparison, polystyrene (PS) and styrene‐acrylonitrile (SAN) resin have been tested. The fracture toughness of PS and SAN resins is determined by the ASTM standard test method for brittle polymers. The fracture toughness of ABS resin is obtained on the basis of the multiple specimens method. The fracture toughness of PS and SAN resin decreases with the increase in moisture absorption. On the other hand, the fracture toughness of ABS resin slightly decreases despite enormous moisture absorption. On the specimens absorbing moisture, a bright whitening region and a milky coloring region are distinguished in the stress‐whitening region, and the milky coloring region expands around the bright whitening region at the crack tip. From the transmission electron microscopic observation, the precraze formation can be recognized in this region. The crack‐tip shielding effect induced by this formation compensates the fracture toughness decrease due to moisture absorption. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 435–442, 1999     

Effect of the compatibilizers on flame-retardant polycarbonate (PC)/acrylonitrile–butadiene–styrene (ABS) alloy

Polycarbonate (PC) blended with acrylonitrile–butadiene–styrene (ABS) has the maximum notched Izod impact strength, which is 58 kg cm cm^-1 for PC/ABS1 and 66 kg cm cm^-1 for PC/ABS2, at a ratio of 80/20 in this study. We selected the ratio of 80/20 to prepare flame-retardant PC/ABS alloys. The compatibility of flame-retardant PC/ABS alloy was examined by differential scanning calorimetry (DSC). The flame-retardant PC/ABS alloy had two values of the glass transition temperature (T_g), indicating that the alloy was not compatible. Three kinds of compatibilizers, methacrylate–butadiene–styrene (MBS), ethylene–vinyl acetate (EVA), and styrene–maleic anhydride (SMA) were used to improve the phenomenon. DSC measurement revealed that after compatibilization the alloy had only one value of T_g, meaning that the alloy became more compatible. Samples were frozen in liquid nitrogen to look at their morphology. We found that the domain sizes were reduced and the surface boundaries were closed and blurred, a feature that could promote the mechanical properties of the alloy. In this study, we also compared the effects of mechanical properties on differential compatibilizers for the flame-retardant PC/ABS alloy. Cycoloy 2800 is a commercial-grade flame-retardant product and was chosen to compare it with our prepared alloys in this study. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 795-805, 1997     

Positron annihilation study of iodine sorption in acrylonitrile–butadiene–styrene

The influence of iodine on the free volume of acrylonitrile–butadiene–styrene (ABS) was investigated by positron annihilation lifetime spectroscopy (PALS). The results indicate the filling of free-volume holes, formation of a positronium–iodine compound (PsI₂/PsI), and possible charge-transfer complexes (CTCs) in the initial stages and the swelling of iodine in the final stages of sorption. The present study also revealed that iodine acts as a chemical quencher of o-Ps. The average size of the free volume suggests that I₃⁻ is the predominant species that fills up the free-volume holes during iodination. The diffusion process in the present case shows non-Fickian behavior and deviates from Fujita's free-volume concept as far as the fractional free volume and diffusion coefficient are concerned. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 2077–2085, 1998     

Flow properties of ABS (acrylonitrile–butadiene–styrene) terpolymer

ABS (acrylonitrile–butadiene–styrene) terpolymer is a two-phase thermoplastic with SAN (styrene–acrylonitrile) copolymer constituting the continuous phase (matrix). The flow properties of ABS with varying molecular parameters were studied using a capillary viscometer at the shear rate range encountered in its processing. The viscosity-average molecular weights (M_v) of matrix SAN with 26% acrylonitrile content are in the range of 90,000 to 150,000, and M_v of poly-butadiene-are in the range of 150,000 to 170,000. The weight-average molecular weight of the matrix SAN is the main controlling factor for the flow properties of ABS at low shear rate, while the molecular weight distribution of the matrix SAN becomes increasingly important with the increase of shear rate. The presence of SAN grafted polybutadiene increases the melt viscosity of ABS by 40–60% over comparable free SAN copolymer and also decreases the activation energy at constant shear stress to 24–25 kcal/mole from the 33–36 kcal/mole for free SAN. The die swell of ABS and SAN can be correlated with the dynamic shear modulus G′, and the melt fracture of ABS and SAN starts at G′ equal to 3.6 × 10⁶ dynes/cm².     

Thermally stimulated current of iodine-doped acrylonitrile–butadiene–styrene thin films

Structural change of acrylonitrile–butadiene–styrene (ABS) terpolymer due to iodine doping has been reported using both infrared (IR) and thermally stimulated current (TSC) techniques. IR investigation revealed the presence of a new stretching band at 640 cm^?1 that indicates the formation of the C-I structure. The TSC spectrum consists of two different decaying charge distributions of opposite polarity, which simply superpose to yield the net current observed. The variation of the position of the negative peak relaxation and its intensity as the iodine percentages increases indicates the formation of different ionic iodine species. The induced ionic dipoles superpose the α-relaxation of ABS. © 1993 John Wiley & Sons, Inc.     

Micromechanical processes and failure phenomena in reactively compatibilized blends of polyamide 6 and styrenic polymers. I. Polyamide 6/acrylonitrile– butadiene–styrene copolymer blends

In this work, in situ investigations of the micromechanical properties of reactively compatibilized blends of polyamide 6 (PA6) and an acrylonitrile–butadiene–styrene copolymer (ABS) were performed with transmission electron microscopy. Three PA6/ABS blends were prepared with a disperse morphology (inclusions of PA6 or ABS) and with a cocontinuous structure. The objective of this work was to study the deformation of the inclusions and the interface between the PA6 phase and the ABS phase. Our transmission electron microscopy investigations revealed that the morphology of the blends was strongly influenced by the asymmetric nature of the interface between PA6 and ABS. In the blends with a PA6 matrix, the interface between PA6 and the ABS inclusions was deformed in tensile deformation under uniaxial loading. A strong influence of the PA6 water content on the (micro)mechanical behavior was observed. Although the “dry” blends behaved in a brittle fashion, the “wet” blends behaved in a ductile fashion with the formation of deformation bands in the matrix (PA6 or ABS), which were initiated by stress concentration at the particles (ABS or PA6, respectively). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Identification of deformation behavior in high‐thermal‐resistant poly(acrylonitrile‐butadiene‐styrene) (ABS)

Deformation mechanisms in postfractured high‐thermal‐resistant poly(acrylonitrile‐butadiene‐styrene) (ABS) were investigated using transmission electron microscopy (TEM) and small‐angle X‐ray scattering (SAXS). Although crazes were clearly identified by TEM, they were not detectable by SAXS. This was possibly due to a short distance between sample and imaging plate in the SAXS set‐up and invisibility of craze fibril scattering from the postfractured samples. A rhomboid‐shaped SAXS pattern was obtained from ABS samples with high ductility but with no crazes shown in the TEM micrographs. It is believed that the rhomboid‐shaped SAXS pattern was generated from matrix shear yielding. The results show that a combination of TEM and SAXS enable us to distinguish crazing and shear yielding in the postfractured ABS. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1316–1321, 2001     

Kinetic investigation of thermooxidative degradation of poly(vinyl chloride)/acrylonitrile–butadiene–styrene blends by isothermal thermogravimetric analysis

The thermal degradation of poly(vinyl chloride)/acrylonitrile–butadiene–styrene (PVC/ABS) blends of different compositions was investigated by means of isothermal thermogravimetric analysis at temperatures of 210°–240°C in flowing atmosphere of air. The Flynn equation, the method of stationary point, and kinetic equation using the Prout–Tompkins model proved to be satisfactory in describing the thermooxidative degradation in the range of 5–30% conversions. The apparent activation energy E and preexponential factor Z were calculated for all compositions of PVC/ABS blends. The ratios E/ln Z are constant for pure and modified PVC and point to the unique mechanism of degradation process. Upon increasing the ratio of ABS in the PVC/ABS blend up to 50%, only the rate of the process is changed; the mechanism remains unchanged. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 833–839, 1999     

Investigation of the rheological behavior of titanium dioxide pigmented acrylonitrile–butadiene–styrene polymer

Titanium dioxide (TiO₂) pigments may be surface‐modified by hydrous oxides, such as alumina (e.g., Cristal 134) or by organic compounds, such as organophosphate (e.g., Tiona 188). In this investigation, the effects of these pigments on the rheological properties of acrylonitrile–butadiene–styrene (ABS) polymer were investigated. With the oscillatory rheometry method in the linear viscoelastic region, the storage and loss moduli versus frequency graph of ABS in the molten state showed two crossover points (COPs) when the surface of the ABS components, that is, poly(styrene‐stat‐acrylonitrile) and poly[(styrene‐stat‐acrylonitrile)‐graft‐polybutadiene] or g‐ABS, had good interaction. The first COPs increased when the TiO₂ content rose to 0.5 and 1.5% in Tiona 188 and Cristal 134 pigmented ABS samples, respectively. With the addition of TiO₂ up to these contents, the polymer–pigment interaction becomes stronger so that the dispersion of the pigments was good. With increasing TiO₂, the first COPs dramatically decreased because of agglomeration of the pigments. The shifting of the first COP may be applied as a criterion to specify the dispersion of TiO₂ particles in the ABS matrix. Scanning electron micrographs showed that the pigments had no effect on the size of the polybutadiene particles. Also, transmission electron micrographs proved that agglomerates of Tiona 188 and Cristal 134 particles were formed above 0.5 and 1.5% TiO₂ contents, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Study on the microphase structure and mechanical properties of the blends of acrylonitrile–butadiene–styrene and sodium sulphonated styrene–acrylonitrile ionomer

The tensile properties of the blends containing neat acrylonitrile–butadiene–styrene (ABS), styrene–acrylonitrile (SAN) and the sodium sulphonated SAN ionomer have been investigated as a function of ion content of the ionomer in the blend. The tensile toughness and strength of the blends showed maximum values at a certain ion content of the ionomer in the blend. This is attributed to the enhanced tensile properties of the SAN ionomer by introduction of ionic groups into SAN and the interfacial adhesion between the rubber and matrix phase in the blend. The interfacial adhesion was quantified by NMR solid echo experiments. The amount of interphase for the blend containing the SAN ionomer with low ion content (3·1mol%) was nearly the same as that of ABS, but it decreased with the ion content of the ionomer for the blend with ion content greater than 3·1mol%. Changing the ionomer content in the blends showed a positive deviation from the rule of mixtures in tensile properties of the blends containing the SAN ionomer with low ion content. This seems to result from the enhanced tensile properties of the SAN ionomer, interfacial adhesion between the rubber and matrix, and the stress concentration effect of the secondary particles. © 1998 SCI.     

Melt processing,mechanical, and fatigue crack propagation properties of reactively compatibilized blends of polyamide 6 and acrylonitrile–butadiene–styrene copolymer

Within a IUPAC study, melt processing, mechanical, and fatigue crack growth properties of blends of polyamide 6 (PA 6) and poly(acrylonitrile–butadiene–styrene) (ABS) were investigated. We focused on the influence of reactive compatibilization on blend properties using a styrene–acrylonitrile–maleic anhydride random terpolymer (SANMA). Two series of PA 6/ABS blends with 30 wt % PA 6 and 70 wt % PA 6, respectively, were prepared with varying amounts of SANMA. Our experiments revealed that the morphology of the matrix (PA 6 or ABS) strongly affects the blend properties. The viscosity of PA 6/ABS blends monotonically increases with SANMA concentration because of the formation of high‐molecular weight graft copolymers. The extrudate swell of the blends was much larger than that of neat PA 6 and ABS and decreased with increasing SANMA concentrations at a constant extrusion pressure. This observation can be explained by the effect of the capillary number. The fracture resistance of these blends, including specific work to break and impact strength, is lower than that of PA 6 or ABS alone, but increases with SANMA concentration. This effect is most strongly pronounced for blends with 70 wt % PA 6. Fatigue crack growth experiments showed that the addition of 1–2 wt % SANMA enhances the resistance against crack propagation for ABS‐based blends. The correlation between blend composition, morphology and processing/end‐use properties of reactively compatibilized PA 6/ABS blends is discussed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

The thermo–oxidative degradation of acrylonitrile–butadiene–styrene copolymers during processing as studied by chemiluminescence

The glow curve obtained upon processing acrylonitrile–butadiene–styrene copolymers (ABS), through various machines, reaches a peak at 180°C. The proper assignment of that peak has required the study of the chemiluminescence (CL) shown by related polymers such as: polybutadiene (PB), styrene–acrylonitrile copolymer (SAN), and polyacrylonitrile (PAN). Three hydroperoxide types associated with the structural units, that is, 1, 2, and cis- and trans-1,4, exhibiting CL peaks at 180, 240, and 340°C, respectively, have been identified in the PB sample. The activation energy (E_a), recorded for the hydroperoxides thermal decomposition, was 15.0 ± 1.0, 17.85 ± 0.9, 20.7 ± 0.8 kcal/mol. PAN shows a CL peak at 180°C. Its occurance is related to the color developed during the thermal treatment. That PAN peak has been attributed to the hydroperoxides generated on the acrylonitrile units neighboring the azomethinic structures. The corresponding E_a is 23.3 ± 1.0 kcal/mol. The same peak (having an identical position and E_a) has been identified with processed ABS and SAN copolymers. As is evident by CL studies, the processing induced oxidation mainly occurs within the SAN phase of the ABS copolymers, though it was also noted within 1,2 units of the PB phase.