Fast mold surface temperature evolution: relevance of asymmetric surface heating for morphology of iPP molded samples

Liparoti, Sara; Sorrentino, Andrea; Guzman, Gustavo; Çakmak, Mükerrem; Titomanlio, G.

doi:10.1039/c5ra04383b

Cited by 33 publications

(42 citation statements)

References 42 publications

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“…A rectangular cavity having a length of 110 mm, a width of 12.7 mm, and a thickness of 1.5 mm was employed. Supplementary information about the cavity geometry is reported elsewhere [28,38].…”

Section: Methodsmentioning

confidence: 99%

“…To obtain a smooth surface, the specimens were microtomed by a Leica microtome. The specimens were then chemically etched following the procedure reported by White and Bassett [53] and previously adopted on similar iPP samples [37,38,42]. In order to determine the effect of the etching procedure on the mechanical results, the samples were etched for different times.…”

Section: Sample Preparationmentioning

confidence: 99%

“…In this paper, we intend to demonstrate the applicability of HarmoniX AFM technique to the characterization of molded polymer samples with complex, nonuniform morphologies [37][38][39][40][41][42], which could influence the mechanical properties of the final object [28,43,44]. To accomplish this objective, a series of HarmoniX tests have been performed on selected polypropylene molded samples.…”

Section: Introductionmentioning

confidence: 99%

“…To accomplish this objective, a series of HarmoniX tests have been performed on selected polypropylene molded samples. These samples have been chosen to highlight the sensitivity of this technique to the variations in morphologies normally found in molded thermoplastic samples [37,38,41,42,45]. HarmoniX tests have been conducted with different scan sizes and resolutions on samples prepared in different ways (i.e., etching procedures), with the objective of studying the relative influence of the preparation methods on the obtained results.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Micromechanical Characterization of Complex Polypropylene Morphologies by HarmoniX AFM

Liparoti

Sorrentino

Speranza

2017

International Journal of Polymer Science

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This paper examines the capability of the HarmoniX Atomic Force Microscopy (AFM) technique to draw accurate and reliable micromechanical characterization of complex polymer morphologies generally found in conventional thermoplastic polymers. To that purpose, injection molded polypropylene samples, containing representative morphologies, have been characterized by HarmoniX AFM. Mapping and distributions of mechanical properties of the samples surface are determined and analyzed. Effects of sample preparation and test conditions are also analyzed. Finally, the AFM determination of surface elastic moduli has been compared with that obtained by indentation tests, finding good agreement among the results.

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Section: Methodsmentioning

confidence: 99%

Section: Sample Preparationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Micromechanical Characterization of Complex Polypropylene Morphologies by HarmoniX AFM

Liparoti

Sorrentino

Speranza

2017

International Journal of Polymer Science

Self Cite

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“…EVO HD 15, Carl Zeiss AG, Jena, Germany) operating at 12 kV. To observe the obtained micro-scale morphology of drawn fibers, samples were chemically etched according the procedure described by Bassett et al [35] and widely used to verify molecular orientation and defect formation [29,36]. Fibers were immersed into a solution at 1 w/v % of potassium permanganate in a mixture of concentrated sulfuric acid, orthophosphoric acid and distilled water (10:4:1 by volume) for 2 h at room temperature.…”

Section: Characterizationmentioning

confidence: 99%

Morphology Development and Mechanical Properties Variation during Cold-Drawing of Polyethylene-Clay Nanocomposite Fibers

et al. 2017

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Abstract:In this work, the influence of composition and cold-drawing on nano-and micro-scale morphology and tensile mechanical properties of PE/organoclay nanocomposite fibers was investigated. Nanocomposites were prepared by melt compounding in a twin-screw extruder, using a maleic anhydride grafted linear low density polyethylene (LLDPE-g-MA) and an organomodified montmorillonite (Dellite 67G) at three different loadings (3, 5 and 10 wt %). Fibers were produced by a single-screw extruder and drawn at five draw ratios (DRs): 7.25, 10, 13.5, 16 and 19. All nanocomposites, characterized by XRD, SEM, TEM, and FT-IR techniques, showed an intercalated/exfoliated morphology. The study evidenced that the nanoclay presence significantly increases both elastic modulus (up to +115% for fibers containing 10 wt % of D67G) and drawability of as-spun nanocomposite fibers. Moreover, at fixed nanocomposite composition, the cold-drawing process increases fibers elastic modulus and tensile strength at increasing DRs. However, at high DRs, "face-to-edge" rearrangement phenomena of clay layers (i.e., clay layers tend to rotate and touch each other) arise in fibers at high nanoclay loadings. Finally, nanocomposite fibers show a lower diameter reduction during drawing, with respect to the plain system, and surface feature of adjustable roughness by controlling the composition and the drawing conditions.

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Flexible Poly(Amide‐Imide)‐Carbon Black Based Microheater with High‐Temperature Capability and an Extremely Low Temperature Coefficient

Liparoti

Landi

Sorrentino

et al. 2016

Adv Elect Materials

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heating element comprises a conductive polymer material. Polymer loaded with conducting fi llers such as carbon-based materials and metal fi bers have been extensively investigated owing to their lightweight and good processability. [1][2][3][4] They are ideal for many smart applications, such as patternable microheaters, temperature sensors, thermoelectric devices, water heaters, and fl exible deicing units. [5][6][7] However, up to now low values of dielectric strength, dimensional stability, thermal insulation, electrical power density, and maximum operating temperature have limited their applications in fl exible heater manufacturing. [ 8,9 ] So far, metal-based microheaters on fl exible foils are the dominant approach in the fi eld. The substitution of conventional microheaters with polymer-based microheaters can expand their applications to extreme environments or for cases, where space and weight allowances are limited. Several approaches related to their formulation and processing have been proposed to overcome the limitations of purely polymer-based solutions. Nanosized particles have received great attention due to their electrical cycle stability and their potential in processing thin fi lms with uniform morphology. In this case, a number of new problems, such as signifi cant particle agglomeration, high interface fraction, and porosity in polymer matrices need to be resolved during nanocomposite production. Probably, the most important issue is the fi ller distribution within the matrix, which depends strongly on the right combination of processing conditions (pressure, temperature, humidity, mixing, etc.), formulation (fi ller content, properties of the matrix), and particle-matrix interactions. [ 10 ] Controlling the impact of all these parameters allows to fi nd the right balance between dispersion and aggregation phenomena in order to prevent either the formation of microagglomerates or of conductive pathway breakage. Generally, it is preferable to decrease the fi ller content value at which the composite becomes conductive (percolation threshold). This is generally achieved by partial segregation of the fi ller or by using conductive nanometric fi llers with high aspect ratio. Among these, nanocarbon materials such as carbon nanotubes (CNTs), graphene, and carbon nanofi bers are used to obtain highly conductive polymer composites with a very low Flexible poly(amide-imide)-carbon black (PAI-CB) composite fi lms, to be applied as high performance microheater foil, have been prepared with a solution/casting technique. The CB dispersion has been carefully controlled in order to improve the thermal and electrical properties of the resulting composites. Morphology and structure of the PAI-CB composite fi lms have been characterized by optical microscopy, atomic force microscopy and FTIR spectroscopy. The effect of the CB dispersion and its interaction with the polymer chains on the thermal and mechanical properties of the composite fi lms have been investigated by using differential scanning calorimetr...

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Fast mold surface temperature evolution: relevance of asymmetric surface heating for morphology of iPP molded samples

Abstract: It is widely accepted that mold temperature has a strong effect on the amount of molecular orientation and morphology developed in a non-isothermal flowing melt.

Cited by 33 publications

References 42 publications

Micromechanical Characterization of Complex Polypropylene Morphologies by HarmoniX AFM

Micromechanical Characterization of Complex Polypropylene Morphologies by HarmoniX AFM

Morphology Development and Mechanical Properties Variation during Cold-Drawing of Polyethylene-Clay Nanocomposite Fibers

Flexible Poly(Amide‐Imide)‐Carbon Black Based Microheater with High‐Temperature Capability and an Extremely Low Temperature Coefficient

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