Influence of temperature and shear rate on the rheology and processability of reprocessed ABS in injection molding process

Boronat, Teodomiro; Segui, Vicente Jesus; Peydró, M.A.; Reig, M. J.

doi:10.1016/j.jmatprotec.2008.06.013

Cited by 82 publications

(44 citation statements)

References 12 publications

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“…A plastic material is melted in the injection-molding machine and then injected into the mold, where it cools and solidifies into the final part. The most commonly used thermoplastics are polystyrene, polypropylene, polyvinyl chloride, and acrylonitrile-butadiene-styrene (ABS) [6][7][8][9]. ABS resins are among the most versatile thermoplastics in the styrenic polymers.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Incomplete Filling Defect for Injection-Molded Air Cleaner Cover Using Moldflow Simulation

Shin

Park

2013

Journal of Polymers

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A large-sized cover part for air cleaner was injection molded with ABS resin, and its incomplete filling defect was analyzed using commercial Moldflow software. To investigate the effect of processing temperature on incomplete filling defect, tensile properties, weight loss, and phase separation behavior of ABS resin were evaluated. The tensile properties of dumbbell samples were not changed up to 250 ∘ C and decreased significantly thereafter. SEM micrographs indicated no significant changes in the status of polybutadiene rubber phase below 250 ∘ C. These different test results indicated that ABS resin little affected the thermal decomposition in processing temperature range. The Moldflow simulation was performed using measured thickness of molded cover and actual mold design with the defects. As expected, the cover part showed unbalanced filling and incomplete sections. To improve these defects, two possible cases of hot runner system have been simulated. When applying modified 5-gate system, the maximum injection pressure was decreased approximately 5.5% more than that of actual gate system. In case of 6-gate system, the maximum injection pressure reduced by 23%, and the injection pressure required to fill is well within the range of the molding equipment. The maximum clamping force of 6-gate system was also significantly reduced than that of actual and 5-gate system.

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Section: Introductionmentioning

confidence: 99%

Analysis of Incomplete Filling Defect for Injection-Molded Air Cleaner Cover Using Moldflow Simulation

Shin

Park

2013

Journal of Polymers

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“…Its main advantage is the good relationship between price and performance, although the presence of a polybutadiene phase brings certain problems when it is submitted to various processing cycles, either by injection or extrusion. The studies carried out by Bai et al (2007), Boronat et al (2009), Karahaliou and Tarantili, (2009) and Perez et al (2010) clearly demonstrate this. Nearly all studies in this area highlight the crosslinking phenomena as the cause of the variation in properties that takes place (loss of ductility).…”

Section: Introductionmentioning

confidence: 64%

“…Cross (1965) and Williams et al (1955) carried out experiments to reproduce the rheological behavior of the materials during the injection process. Reig in his works (2005) and (2007), and Boronat et al (2009), applied these models in their studies on reprocessed ABS + PC and ABS respectively. Reig in his 2007 work determined a Material Processability Index (MPI) from three mixtures of ABS + PC with a different Melt Flow Index (MFI).…”

Section: Introductionmentioning

confidence: 99%

Recovery of recycled acrylonitrile–butadiene–styrene, through mixing with styrene–ethylene/butylene–styrene

Peydró

Parrés

Crespo

et al. 2013

Journal of Materials Processing Technology

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Recovery of recycled acrylonitrile-butadiene-styrene (ABS) through mixing with styrene-ethylene/butylene-styrene (SEBS) has been studied in this paper. To simulate recycled ABS, virgin ABS was processed through 5 cycles, at extreme processing temperatures, 220 ºC and 260 ºC. The virgin ABS, the virgin SEBS, the recycled ABS and the mixtures were mechanically, thermally and rheologically characterized after the various cycles of reprocessing in order to evaluate their corresponding properties and correlate them with the number of cycles undergone. With these data and using CAE (Computer Aided Engineering) the injection process was simulated by obtaining the optimal injection process parameters. Mixtures were injected at two temperatures in a sensorised mold correlating the shrinkage of the parts with temperature.The results show that tensile strength of ABS remains practically constant as the number of reprocessing cycles increases, while in the material injected with SEBS the tensile strength decreases. Concerning the Charpy notched impact strength; the values of the ABS reprocessed at 220 ºC remain more or less unchanged, while the values for 260 ºC show a significant decrease. The adhesion of the SEBS causes, in both cases, an increase in impact strength. DSC techniques enabled us to observe how the glass transition temperature (T g ) remains more or less constant regardless of the number of cycles or the temperature, whereas the crosslinking is much greater in the samples reprocessed at 260 ºC.Finally, the viscosity decreases with each cycle and this decrease becomes even more noticeable with the addition of SEBS, and also that the parts molded at lower temperatures have less shrinkage.

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“…Different temperatures (above and below the injection temperature recommended by the provider [18]) were used for rheological characterization (175C and 185C).…”

Section: Characterization Of Sebs Blendsmentioning

confidence: 99%

Validation of the Use of SEBS Blends as a Substitute for Liquid Silicone Rubber in Injection Processes

Juárez

Balart

Boronat

et al. 2013

Materials and Manufacturing Processes

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Liquid silicone rubber is an interesting material at an industrial level, but there are great difficulties in the design and machining of molds, and in addition, it cannot be processed using conventional equipment. Therefore, new lines of research have focused on the search for new materials capable of providing final properties similar to liquid silicone rubber, that can also be engineered using simple, conventional processes and machinery. In this investigation, a range of compatible blends, based on two commercial grades of styrene-b-ethyleneco-butylene-bstyrene (SEBS) thermoplastic elastomer, was studied in order to obtain a range of different Shore A hardness blends for industrial applications where liquid silicone rubber (different hardness) is currently used. The two blended elastomers used had widely differing Shore A hardness values (5 and 90). Once the blended materials had been characterized, the Cross and Williams et al.[20] (Cross-WLF) mathematical model was applied in order to obtain theoretical performance curves for the viscosity of each of the blends. After this, a model was developed using the Computer Aided Engineering (CAE) software package Autodesk Moldflow 2012TM. This computer modeling validated the results obtained from the mathematical models, thus making available to process engineers the full range of hardnesses necessary for industrial products (where liquid silicone rubber is used), while still providing the advantages of thermoplastic injection molding.

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Influence of temperature and shear rate on the rheology and processability of reprocessed ABS in injection molding process

Cited by 82 publications

References 12 publications

Analysis of Incomplete Filling Defect for Injection-Molded Air Cleaner Cover Using Moldflow Simulation

Analysis of Incomplete Filling Defect for Injection-Molded Air Cleaner Cover Using Moldflow Simulation

Recovery of recycled acrylonitrile–butadiene–styrene, through mixing with styrene–ethylene/butylene–styrene

Validation of the Use of SEBS Blends as a Substitute for Liquid Silicone Rubber in Injection Processes

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