Crystal structures and orientation development in tubular film extrusion of syndiotactic polypropylene and isotactic polypropylene

Choi, Dongman; White, James L.

doi:10.1002/pen.10871

Cited by 16 publications

(7 citation statements)

References 23 publications

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“…The isotactic polypropylene (i-PP) crystalline structure exists in a monoclinic a-form with adjusted orthogonal crystal axes labeled, a*, b, and c. 29,30 Figure 11 shows the pole figures for crystal axes; 100 (a*), 010 (b), and 001 (c) with a linear intensity scale, for the four blown films in this study. For neat PPC300 film, its b axis was oriented strongly along the ND.…”

Section: Characterization Of Blown Filmsmentioning

confidence: 99%

Blown films with balanced in-plane properties from polypropylene-clay nanocomposites though silane coupling

Ren

Jayaraman

2020

Journal of Plastic Film & Sheeting

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Layered silicates present interaction sites at both faces and edges of the nanolayers and silane coupling agents that locate at both sites lead to polymer nanocomposites with superior melt strength and properties. This work’s objective was (a) to investigate the effectiveness of solvent-free, vapor phase, silane treatment of the nanolayers for formulating masterbatches and (b) to compare the mechanical properties of 1 mil thick blown films from polypropylene copolymer nanocomposites with such coupling, to films from the neat polypropylene. The nanocomposite blown film tensile modulus and tensile strength improved along both the draw direction and the transverse direction. In addition, their elongation to failure was close to 500% along both directions, in contrast to values of 500% along MD and 170% along TD for the neat PP copolymer. These trends may be understood in terms of the crystalline lamellar orientation distribution in the films. FESEM images revealed that cross-hatched lamellae were absent from the unfilled PP blown film and were pervasive in the nanocomposite blown film. The nanolayers were oriented in the film plane with the longer dimension largely along the MD. The lower extent of lamellar orientation around nanolayers may be attributed to the strong reduction in the polymer chain mobility attached to the nanolayers.

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Section: Characterization Of Blown Filmsmentioning

confidence: 99%

Blown films with balanced in-plane properties from polypropylene-clay nanocomposites though silane coupling

Ren

Jayaraman

2020

Journal of Plastic Film & Sheeting

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“…An improvement in mechanical properties was noted as a function of orientation. Choi et al [2] compared the tubular films of sPP (syndiotactic polypropylene) and iPP prepared using an extrusion process. The main findings were that the orientation of the amorphous component, developed in sPP and iPP films, changes similarly to that of the orientation of the crystalline component.…”

Section: Introductionmentioning

confidence: 99%

Orientated CNT‐polypropylene nanocomposite films made from extruded monofilaments

Tanami¹,

Wachtel²,

Marom³

2013

Polymer Composites

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In this study, a method for making an orientated polymer nanocomposite film was developed. Melt‐drawn nanocomposite monofilaments of isotactic polypropylene and acicular nanofillers, i.e. carbon nanotubes (CNT) or vapor grown carbon nanofibers (VGCF), were prepared and characterized from the aspect of polymer chain orientation, mechanical properties, and overall morphology. A marked improvement in mechanical properties was observed as a function of the addition of CNT, increasing draw down ratio (DDR) and annealing. Nanocomposite films were prepared from drawn monofilaments by hot‐pressing under low pressure in order to maintain the orientation of the monofilaments. Wide angle X‐ray diffraction showed a high degree of residual orientation in the films. Electron microscopy (high‐resolution scanning electron microscopy, transmission electron microscopy) unexpectedly revealed that the CNT‐matrix interface is amorphous. However, differential scanning calorimetry found no measurable influence of the CNT on the overall crystallinity as determined by the enthalpy of melting of the matrix. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers

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“…At the same time, crystal orientation is a key factor that influences the properties of I‐PP products. Therefore, there were some studies using pole figures on the crystal orientation of injection‐molded polypropylene compounds,4 polypropylene sheets produced by die‐drawing and rolling,5–7 and extruded tubular film of I‐PP 8…”

Section: Introductionmentioning

confidence: 99%

Crystal form and orientation of isotactic polypropylene samples prepared by vibration‐injection molding

Zhang

Zeng

Zhu

et al. 2007

J of Applied Polymer Sci

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A vibration-injection molding equipment was developed to prepare isotactic polypropylene injection samples to investigate their crystal form and orientation. Wide-angle X-ray scattering experiments (WAXD) were conducted in two modes: theta-theta mode and tube-fixed mode. Through vibration-injection molding, in additional to a form, b form, or g form can be obtained under different conditions. At high melt temperature (230), b-PP can be induced and the core of the sample contains more b-PP than the surface. At low melt temperature (190), g-PP can be induced and the core and the surface of the sample contain approximate same proportion of g-PP. Pole figures show that a-PP of a static sample just orientates slightly along M direction, while that of vibration samples orientate much stronger. The orientation of the normal of (040)a plane of the sample obtained at T 5 2308C, f 5 0.5 Hz, and P v 5 75 MPa is preferred in M direction, and the orientation of the normal of (040)a plane of the sample obtained at T 5 1908C, f 5 1.5 Hz, and P v 5 35 MPa is preferred in N direction. b-PP and g-PP do not show obvious orientation.

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Crystal structures and orientation development in tubular film extrusion of syndiotactic polypropylene and isotactic polypropylene

Cited by 16 publications

References 23 publications

Blown films with balanced in-plane properties from polypropylene-clay nanocomposites though silane coupling

Blown films with balanced in-plane properties from polypropylene-clay nanocomposites though silane coupling

Orientated CNT‐polypropylene nanocomposite films made from extruded monofilaments

Crystal form and orientation of isotactic polypropylene samples prepared by vibration‐injection molding

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