Effect of Rubber Content of ABS on Properties of PC/ABS Blends. I. Rheological,Mechanical, and Thermal Properties

ABSTRACT

The effect of rubber content of poly (acrylonitrile butadiene styrene) (ABS) on compatibility and properties of polycarbonate (PC)/ABS blend systems has been investigated. The rheological, mechanical, physical, and thermal properties of PC/ABS blend systems containing ABS of different rubber content were studied. The reduced torque data on Torque Rheocord indicated improved processability of PC by addition of ABS, however, in ABS-rich compositions, higher rubber content reduces the extent of improvement. The tensile strength of PC decreased with addition of ABS to it but PC-rich compositions have a nearly additive response. The deviation form additivity for blends having higher rubber ABS was more pronounced. However, the impact strength of blends having higher rubber ABS were higher than other types and showed a positive deviation from additivity with variation in compositions. The blends containing ABS with lower rubber content showed a single glass-transition temperature (Tg) in differential scanning calorimetry studies (DSC) in the whole composition range indicating miscibility. Although two Tgs, one associated with PC phase and one with ABS phase, were observed for blends containing high rubber ABS, the shift in Tgs with respect to pure component values indicates partial miscibility. The decrease in the extent of shift with increase of ABS in these blends indicates undesirable phase separation due to poor adhesion of higher level of rubber content.     

Deformation of rubber-toughened polycarbonate: Macroscale analysis of the damage zone

Two commercial core-shell rubbers were used as impact modifiers for polycarbonate (PC). Specimens with a single semicircular edge notch were stretched uniaxially in order to study the prefracture damage evolution of blends under a triaxial tensile stress state. The irreversible deformation of modified PC included a cavitation mechanism in addition to the three shear modes of unmodified PC. At the macroscopic level, the cavitation condition could be described by a mean stress concept. The corresponding critical volume strain for cavitation in PC blends was determined to be independent of rubber content but differed for the two impact modifiers. The critical volume strain for cavitation was used as an index of cavitation resistance for the impact modifiers. The effect of rubber content and temperature on Izod impact strength of the PC blends was also reported. From the relationship between the cavitation resistance and the Izod impact strength, it was proposed that impact modifiers with a higher cavitation resistance impart better toughness to blends with PC. © 1994 John Wiley & Sons, Inc.     

三元乙丙橡胶增韧PET/PC共混物的研究

采用三元乙丙橡胶（EPDM）及甲基丙烯酸环氧丙酯接枝三元乙丙橡（EPDM-g-GMA）作为PET/PC共混物的改性剂,并对共混体系的力学性能、相容性和断裂机理进行研究。力学性能测试结果表明EPDM-g-GMA质量分数为15%～20%时,共混体系实现了脆韧转变,当加到25%时冲击强度最高可达860 J/m,实现超韧;当PET/PC组成比为48/32时,PET/PC相容性最好,共混体系力学性能最佳。EPDM-g-GMA中环氧官能团与PET的端羧基、羟基发生反应使共混体系相容性提高。SEM结果显示共混物的增韧机理是基体的剪切屈服。     

Fabrication of Super Tough Polycarbonate/Styrene-Etylene-Butylene-Styrene Grafted Maleic Anhydride (SEBS-g-MA) Blends: Morphological,Short Term Static Mechanical and Fracture Performance Interpretation

Impact behaviours, tensile properties and fracture performance of polycarbonate (PC)/styrene ethylene-butylene-styrene-grafted-maleic anhydride (SEBS-g-MA) copolymer blends at SEBS-g-MA volume fraction Φ_d = 0–0.39 are evaluated. In presence of rubber a significant augmentation in notched Izod impact strength was observed while tensile modulus and strength decreased. Morphological studies reveal good interaction between the PC and the rubber particles showing homogeneous dispersion of SEBS-g-MA in the polycarbonate matrix. Interparticle distance of the dispersed phase evaluated from the morphology studies by scanning electron microscopy (SEM) and the impact strength dependence on the concentration of the blending rubber were analysed. The essential work of fracture approach is applied to study fracture properties of the blends. With increasing SEBS-g-MA concentration nonessential or plastic work increased which explained the enhancement of impact strength of blends.     

Blends of bisphenol A polycarbonate and rubber‐toughened styrene–maleic anhydride copolymers

The morphology and mechanical properties of polycarbonate (PC) blends with rubber‐toughened styrene–maleic anhydride copolymer materials (TSMA) were investigated and compared with the properties of blends of PC with acrylonitrile–butadiene–styrene (ABS) materials. The PC/TSMA blends showed similar composition dependence of properties as the comparable PC/ABS blends. Polycarbonate blends with TSMA exhibited higher notched Izod impact toughness than pure PC under sharp‐notched conditions but the improvements are somewhat less than observed for similar blends with ABS. Since PC is known for its impact toughness except under sharp‐notched conditions, this represents a significant advantage of the rubber‐modified blends. PC blends with styrene–maleic anhydride copolymer (SMA) were compared to those with a styrene–acrylonitrile copolymer (SAN). The trends in blend morphology and mechanical properties were found to be qualitatively similar for the two types of copolymers. PC/SMA blends are nearly transparent or slightly pearlescent. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1508–1515, 1999     

Influence of ABS type on morphology and mechanical properties of PC/ABS blends

The morphology and the mechanical properties of polycarbonate (PC) blends with different acrylonitrile–butadiene–styrene (ABS) materials were investigated. PC/ABS blends based on a mass-made ABS with 16% rubber and large (0.5–1μm) rubber particles are compared to blends based on an emulsion-made ABS with 50% rubber and small, monodisperse (0.12 μm) rubber particles over the full range of blend compositions. The blends with the bulk ABS showed excellent impact strength for most compositions, and those containing 50 and 70% PC exhibited ductile to brittle transition temperatures below that of PC. The blends with the emulsion ABS showed excellent toughness in sharp notch Izod impact tests at room temperature and in standard notch Izod impact tests at low temperatures near the T_g of the rubber. By melt blending the various ABS materials with a styrene–acrylonitrile (SAN 25) copolymer, materials with lower rubber concentrations were obtained. These materials were used in blends with PC to make comparisons at constant rubber concentration of 5, 10, and 15%. The results of this investigation show that brittle ABS materials can produce tough PC–ABS blends. It is apparent that small rubber particles toughen PC–ABS blends at lower rubber concentrations and at lower temperatures than is possible with large rubber particles. However, additional work is needed to understand the nature of toughening in these PC–ABS blends with different rubber phase morphologies. It is of particular interest to understand the exceptional ductility of some of the blends at low temperatures. © 1994 John Wiley & Sons, Inc.     

“核-壳”型硅橡胶对聚碳酸酯回收料的增韧及阻燃改性研究

采用"核-壳"型硅橡胶对聚碳酸酯(PC)回收料进行增韧及阻燃改性,考察了该共混体系的力学性能、阻燃性能、断裂面形貌及热稳定性。研究表明:两相不相容导致"核-壳"型硅橡胶与PC回收料共混没有增韧效果。只有添加环氧树脂或苯乙烯-马来酸酐共聚物作为增容剂,其缺口冲击强度才能获得大幅提高。冲击断裂面形貌观察显示:增容剂能有效提高"核-壳"型硅橡胶的聚甲基丙烯酸酯壳与PC基体间的界面黏结性,降低两相表面张力,使硅橡胶粒子在基体中获得单分散分布,这是取得优异增韧效果的关键因素;并根据实验结果分析了增韧机理。"核-壳"型硅橡胶不仅可以有效地增韧PC回收料,也能显著提高其阻燃性能。在共混物燃烧过程中,硅橡胶能迅速迁移到PC表面,形成高阻燃性的炭保护层;同时在PC基体与硅橡胶之间形成交联结构,从而对PC回收料产生阻燃作用。因此,添加质量分数为7%的"核-壳"型硅橡胶和3%的增容剂,就可使PC回收料的阻燃级别达到UL94V-0级。     

Studies on the transesterification of polycarbonate/poly(ethylene terephthalate) blends. II: Effect of transesterification on the compatibility and crystallization behaviour of the blends

The effect of transesterification on the compatibility of polycarbonate poly(ethylene terephthalate) (PC/PET) blends and the crystallization and melting behaviour of PET was studied. The results show that with increase of the reaction extent, the compatibility of the blends was enhanced during melt-processing, from completely incompatible to partially compatible, then to complete compatibility. In addition, with the increase of reaction extent, the crystallization ability and crystallinity of PET decreased. A new endotherm peak was discerned in DSC thermograms and its position and peak area were closely related to the reaction conditions, which was explained by the changes in the crystalline regions in the PC/PET blends. The effect of transesterification on the multiple melting behaviour of PET in PC/PET blends is also discussed.     

Influence of rubber content in ABS in wide range on the mechanical properties and morphology of PC/ABS blends with different composition

A series of acrylonitrile–butadiene–styrene (ABS) with different rubber content were prepared by diluting ABS grafting copolymer containing 60% rubber with a styrene–acrylonitrile copolymer. ABS prepared were blended with bisphenol‐A‐polycarbonate (PC) at the ratio of 70/30, 50/50, and 30/70 to prepare PC/ABS blends. Influence of rubber content in ABS on the properties of ABS and PC/ABS blends were investigated. PC/ABS blends with different compositions got good toughness when the rubber in ABS increased to the level that ABS itself got good toughness. The tensile properties and processability of PC/ABS blends decreased with the increase of the total rubber content introduced into the blends. ABS with the rubber content of 30 wt% is most suitable to be used to prepare PC/ABS blends. The rubber content in ABS affected the viscosity of ABS, and subsequently the viscosity ratio of PC to ABS. As a result, the morphology of PC/ABS blends varied. The increase of rubber content in ABS results in finer structure of PC/ABS blends. POLYM. ENG. SCI. 46:1476–1484, 2006. © 2006 Society of Plastics Engineers.     

Effects of thermoplastic elastomer on the morphology and mechanical properties of glass fiber‐reinforced polycarbonate/acrylonitrile–butadiene–styrene

This article investigated the influence of thermoplastic elastomer like acrylonitrile–butadiene–styrene (ABS) high rubber powder (HRP), and ethylene methylacrylate (EMA) on the mechanical performances, flow ability, and morphology of glass fiber‐reinforced polycarbonate (PC)/ABS blends. Blending was carried out through a twin‐screw extruder, and all testing specimens were shaped by an injection molding machine. Experimental results showed that the toughening effect of EMA was more obvious than HRP due to fracture mechanism like crazing, shear yielding occurred in corporation with EMA. About 15 wt% glass‐fiber (GF) reinforcement and 6 wt% EMA toughening can get a balanced behavior among strength, stiffness, and toughness for superior performance of the polymer. POLYM. ENG. SCI., 59:E144–E151, 2019. © 2018 Society of Plastics Engineers     

bPE-g-MAH对PC/bPE共混物力学性能与断面形态结构的影响

利用熔融接枝法制备了双峰聚乙烯接枝马来酸酐(bPE-g-MAH),将其用作聚碳酸酯/双峰聚乙烯(PC/bPE)共混物的增容剂。通过力学性能测试和扫描电镜分析,研究了bPE-g-MAH对共混物相容性和力学性能的影响。结果表明:bPE-g-MAH的加入使得PC和bPE两相的界面黏合作用增强,使PC/bPE共混物的冲击强度显著提高。     

Investigation of the polycarbonate/crushed‐rubber‐particle interphase by nanoindentation

Nanoindentation tests were carried out to determine the nanomechanical characteristics of recycled polycarbonate (PC)/crushed‐rubber blends. Both the modulus and hardness of the matrix, particles, and PC/rubber interphase were obtained. Different blends with untreated, flamed, and washed rubber particles were characterized. The results proved the good recyclability of PC. Indentations performed in the PC matrix showed that the rubber acted as a plasticizer for the PC matrix, probably because of a diffusion of free rubber chains. This plasticizing effect was accentuated by flamed rubber particles in the blends. The results showed that flame and methanol treatments modified the morphology of the rubber particles. These treatments induced a significant increase in the nanomechanical properties of the rubber particles. In the interface region between the PC matrix and rubber particles, a gradual change in the mechanical properties was confirmed. Profiles of the interface modulus and hardness helped to determine the interface width according to the particle treatment. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2687–2694, 2007     

Injection molding of polypropylene/polycarbonate blends

This work deals with the effects of material and processing parameters on the mechanical behavior and morphology of noncompatlbilized polypropylene-polycarbonate (PP-PC) blends. The blends containing between 0 and 40 vol. percent of polycarbonate were compounded using a twin screw extruder and converted by injection molding using molds with rectangular as well as dogbone shaped cavities. The blends exhibit a complex skin-core morphology which evolves with the composition. Despite the absence of interfacial adhesion, the low strain modulus increases with PC concentration and follows approximately the Takayanagi model for systems with perfect adhesion. A slight increase of stiffness and strength with increasing PP/PC viscosity ratio is also observed. Weldline strength of these blends is generally poor and decreases with the increasing PC concentration.     

Phase morphologies and mechanical properties of high‐impact polystyrene (HIPS) and polycarbonate blends compatibilized with polystyrene and polyarylate block copolymer

Phasemorphology and mechanical properties of blends of high‐impact polystyrene (HIPS) and polycarbonate (PC) blends compatibilized with a polystyrene (PS) and polyarylate (PAr) (PS–PAr) block copolymer were investigated. Over a broad range of composition from 50/50 through 30/70, HIPS/PC blends formed cocontinuous structures induced by the flow during the extrusion or injection‐molding processes. These cocontinuous phases had heterogeneity between the parallel and perpendicular directions to the flow. The micromorphology in the parallel direction to the flow consisted of stringlike phases, which were highly elongated along the flow. Their longitudinal size was long enough to be longer than 180 μm, while their lateral size was shorter than 5 μm, whereas that in the perpendicular direction to the flow showed a cocontinuous phase with regular spacing due to interconnection or blanching among the stringlike phases. The PS–PAr block copolymer was found to successfully compatibilize the HIPS/PC blends. The lateral size of the stringlike phases could be controlled both by the amount of the PS–PAr block copolymer added and by the shear rate during the extrusion or injection‐molding process without changing their longitudinal size. The HIPS/PC blend compatibilized with 3 wt % of the PS–PAr block copolymer under an average shear rate of 675 s^?1 showed a stringlike phase whose lateral size was reduced almost equal to the rubber particle size in HIPS. The tensile modulus and yield stress of the HIPS/PC blends could be explained by the addition rule of each component, while the elongation at break was almost equal to that of PC. These mechanical properties of the HIPS/PC blends can be explained by a parallel connection model independent of the HIPS and PC phases. On the other hand, the toughness factor of the HIPS/PC blends strongly depended on the lateral size of the stringlike phases and the rubber particle size in the HIPS. It was found that the size of the string phases and the rubber particle should be smaller than 1.0 μm to attain a reasonable energy absorbency by blending HIPS and PC. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2347–2360, 2001     

Influence of miscibility on the morphology and properties of polycarbonate/(maleic anhydride)-grafted-polypropylene blend

Maleic-anhydride-grafted polypropylene (MAH-g-PP) was added to polycarbonate (PC) as a processing agent. Its influence on the morphological, thermal, rheological, and mechanical properties of PC/MAH-g-PP blends was investigated by differential scanning calorimetry (DSC), dynamic mechanical spectroscopy (DMS), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), dynamic contact angle goniometry, and tensile and impact strength experiments. The results indicated that the processability and miscibility of the blends were improved significantly by addition of 5–20 wt% MAH-g-PP to PC. The melting temperature of MAH-g-PP increased as the relative composition of MAH-g-PP in the blends increased mainly because of enlargement of the crystallite size. The DSC, FTIR as well as SEM results strongly suggested that a chemical reaction might have taken place between the PC and MAH-g-PP. This chemical reaction could have contributed to the improvement of the mechanical properties of the blends and the miscibility between the PC and MAH-g-PP components.     

Thermal aging of impact-modified polycarbonate

Glassy polymers undergo relatively rapid physical aging just below their glass transition temperatures that can lead to embrittlement of normally tough materials like polycarbonate (PC). One approach for solving the embrittlement problem is to incorporate an impact modifier that can cause toughening when the matrix loses its inherent ductility due to physical aging. The effects of thermal aging below the glass transition temperature of polycarbonate on selected properties of blends of PC with various core-shell impact modifiers have been studied. Observed changes in mechanical properties are related to rubber content, free volume, fracture morphology, discoloration, enthalpy relaxation, glass transition temperature, intrinsic viscosity, and dynamic mechanical behavior. Blend mechanical properties are affected by chemical changes in the impact modifier that occur simultaneous with the physical aging of the PC matrix. The degradation mechanisms involved reduce the effectiveness of the modifier for toughening and also lead to a loss of molecular weight of the PC matrix. Blends containing 10% methacrylated butadiene-styrene (MBS) core-shell impact modifiers give the maximum extension of time to embrittlement at 135°C in air. More thermally stable modifiers are required for further extending the ductile mode of failure for physically aged PC blends.     

Effect of SEPS as a novel compatibilizer on the properties and morphology of PP/PC/POE blends

A novel macromolecular compatibilizer, styrene-ethylene-propylene-styrene (SEPS) with high content of styrene, was investigated for the purpose of improving the compatibility of PP (polypropylene)/PC (polycarbonate)/POE (ethylene-octene copolymer) blends. SEPS shows a remarkable compatibilizing effect since it has a particular structure with the EP-compatible aliphatic segments, which is well miscible with the nonpolar PP and olefinic elastomer POE domains, and S-chain segments which exhibit strong affinity with PC because of the similar molecular structure. Its compatibilizing effect was examined in terms of the mechanical, morphological, and thermal properties. The compatibilized PP-based blends represent remarkable improvement in impact strength and balanced tensile strength. When 5 wt % SEPS was added to PP/PC/POE blends (20 wt % POE), the impact strength of the blends was enhanced from 24 to 43 kJ/m² without obvious drop in the tensile strength. Their morphologies show a decreasing and much more homogeneous size of dispersed PC and POE particles through addition of SEPS, and the fracture surface morphologies change from irregular mosaic to the mix of mosaic and striation, and finally the regularly distant striation. The special morphology structure that resulted from the effect of the compatibilizer could be a key for enhancement of toughness and balanced rigidity of the blends. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Toughening modification of PBT/PC blends with PTW and POE

New toughened poly(butylene terephthalate) (PBT)/bisphenol A polycarbonate (PC) blends were obtained by melt blending with ethylene–butylacrylate–glycidyl methacrylate copolymer (PTW) and ethylene‐1‐octylene copolymer (POE) in a twin‐screw extruder. The mechanical properties of PBT/PC blends were investigated. The presence of PTW or POE could improve the mechanical properties except for the tensile strength and flexural properties of the PBT/PC blends. However, a combination use of PTW and POE had a strong synergistic effect, leading to remarkable increases in the impact strength, elongation at break, and Vicat temperature and some reduction of the tensile strength and flexural properties. The relationship between mechanical properties and morphology of the PBT/PC/PTW/POE blends was studied. The morphology was observed by scanning electron microscopy and the average diameter of dispersed phase was determined by image analysis, and the critical interparticle distance for PBT/PC was determined. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 54–62, 2006     

Structured latex particles based on natural rubber for high-impact polymer blends

Natural latex (NR) particles, modified with a hard shell of poly(methyl methacrylate) (PMMA) and with a substructure of PMMA (type "NR-M") or polystyrene (type "NR-SM"), were tested as compatibilizers in blends of polycarbonate (of bisphenol A, PC) and PMMA or PS. During melt blending, the modified NR particles were torn apart, from an original size of >0.5 μm down to ≅0.1 μm in diameter. Two different types of particle distribution were observed in the blends: in PC/PMMA/NR-M blends, the NR-M particles were dispersed in the PMMA phase, whereas, in PC/PS/NR-SM blends, the NR-SM particles formed interface layers between PC and PS phase domains. The latter blend morphology, distinguished by continuous rubbery interface layers of NR-SM, turned out to be mechanically excellent in injection-moulded parts. The poor impact strength of PC/PS was raised by an order of magnitude. The effect depends on the orientation in the injection-moulded test bars.     

A preliminary study of blends of bisphenol a polycarbonate and poly(ethylene terephthalate)

The microstructure of blends of bisphenol A polycarbonate (PC), and poly(ethylene terepthalate) (PETP) has been studied by solvent extraction, infrared spectrophotometry, differential scanning calorimetry and dynamic mechanical thermal analysis. The blends appear to contain two amorphous phases over the whole composition range. The tensile behaviour and the Charpy impact strength of some of the blends have been determined, before and after heat treatment at 125°C for 18 hours. Improved performance of the blends, compared with that of the homopolymers PC and PETP, has been demonstrated.