The thermomechanical environment and the microstructure of an injection moulded polypropylene copolymer

Viana, J. C.; Cunha, António M.; Billon, Noëlle

doi:10.1016/s0032-3861(02)00253-7

Cited by 94 publications

(103 citation statements)

References 25 publications

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“…During processing, a polymer is subjected to high gradients of temperature, pressure, and deformation rates. Therefore, its morphology and crystallization kinetics under quiescent conditions will be different from that under processing conditions [1][2][3][4][5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Optical monitoring of polypropylene crystallization during injection molding

Favaro

Marinelli

Farah

et al. 2007

Polymer Engineering & Sci

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The nonisothermal crystallization of polypropylene resins, i-PP, during injection molding, using an optical device inserted in the injection mold cavity was monitored. The device detected the change of optical properties which occurs in polymers during their crystallization process; thus the intensity of a laser beam after it passed through the crystallizing polymer was measured during an injection molding cycle. The collected light intensity after the end of the cycle was correlated with the morphologies and final crystallinity degree of the samples. The influence of nucleating agents and the change of the parameters of the injection molding process on the morphology and optical signals were also investigated. The morphologies were analyzed by polarized light optical microscopy, PLOM. The % of crystallinity of the samples was measured by wide angle X-rays diffraction, WAXS. It was concluded that the optical device was sensible to different polymer crystallization kinetics, morphology type, and changes in the injection molding parameters. It was also found that the mold temperature and packing pressure and time were the factors that affected most the kinetics of crystallization of these polymers in this particular disk geometry. The WAXS results showed that the lower the final light intensity the higher the % of crystallinity in the samples. POLYM. ENG. SCI.,

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Section: Introductionmentioning

confidence: 99%

Optical monitoring of polypropylene crystallization during injection molding

Favaro

Marinelli

Farah

et al. 2007

Polymer Engineering & Sci

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“…In order to be able of predicting the mechanical properties of injection moulded components a methodology based on thermomechanical indices has been proposed. These thermomechanical indices relate to main physical phenomena involved and aim at evaluating the morphology development (Cunha, 2000;Viana 2002):…”

Section: Relationships Between Processing and Moulding Mechanical Promentioning

confidence: 99%

“…Using similar methodologies, the maximization of the mechanical properties of injection moulded components can be performed also by computer simulations. The simulations allow the computation of the thermal and mechanical fields imposed to the polymer during processing, letting the calculation of thermomechanical indices that can be used to estimate the mechanical properties of the moulded component (Viana, 1999;Viana, 2002). These latter can be maximized by variation of the processing conditions, changes upon the part geometry, exploitation of different gating and cooling system options.…”

Section: Multi-objective Optimization Of the Mechanical Behaviour Of mentioning

confidence: 99%

Optimization of Injection Moulded Polymer Automotive Components

Ribeiro¹,

Viana²

2011

New Trends and Developments in Automotive System Engineering

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“…A great deal of research has been performed on skin-core morphology in an injection-molded specimen [1][2][3]. The skin morphology is different from that in other locations because moving molten PP is immediately frozen at the cold cavity wall.…”

Section: Introductionmentioning

confidence: 99%

“…Our purpose in this study was to clarify the skin morphology formation in the [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] μm depth region by a WAXD analysis of three types of nucleated PP and by an original 2-D viscoelastic flow simulation program. Birefringence with a polarizing optical microscope (POM) and micro-beam synchrotron WAXD were utilized for evaluating injection-molding-induced morphology.…”

Section: Introductionmentioning

confidence: 99%

Crystallization of polypropylene near the surface in injection‐molded plaques: A comparison of morphology and a numerical analysis

Kobayashi

Otsuki²,

Kanno

et al. 2010

Polymer Engineering & Sci

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Skin morphology formation on injection-molded isotactic polypropylene (PP) was investigated using micro-beam synchrotron wide-angle X-ray diffraction and numerical simulation. The 1-20-μm depth range was characterized with an X-ray beam of 0.273 μm × 0.389 μm in size. From an evaluation of doping nucleating agents (NA) in PP, the NAs did not work at a depth of 1 μm. α-specified NA affected crystallization within a 5-μm depth. β-specified PP showed α-form crystallinity at the 5-20 μm depth. The mesomorphic crystal near the surface showed extremely high orientation. From viscoelastic flow simulation, PP molecules near the surface were oriented in the flow direction by extensional flow in the flow front, but freezing occurred faster than flow-induced crystallization. It was estimated that the delay of crystallization occurred during the transient temperature. The deformation rate did not cause a difference in crystal morphology near the surface, but the cooling rate did.3

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The thermomechanical environment and the microstructure of an injection moulded polypropylene copolymer

Cited by 94 publications

References 25 publications

Optical monitoring of polypropylene crystallization during injection molding

Optical monitoring of polypropylene crystallization during injection molding

Optimization of Injection Moulded Polymer Automotive Components

Crystallization of polypropylene near the surface in injection‐molded plaques: A comparison of morphology and a numerical analysis

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