Modeling and experimental study of birefringence in injection molding of semicrystalline polymers

Kim, Kyuk Hyun; Isayev, A. I.; Kwon, Keehae; Sweden, C. van

doi:10.1016/j.polymer.2005.02.057

Cited by 24 publications

(25 citation statements)

References 39 publications

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“…Earlier works have showed the distributions of the deformation rate, the first normal stress difference, strain, and temperature in the fountain flow [5–10]. For understanding the frozen‐in orientation, viscoelastic flow history in the upstream should be known.…”

Section: Resultsmentioning

confidence: 99%

“…A lot of previous work has been carried out for simulating molecular orientation in an injection‐molded specimen [3–10]. Hot molten polymer is moving into the mold cavity by the fountain flow.…”

Section: Introductionmentioning

confidence: 99%

“…The approximation leads to a Hele‐Shaw type flow, which neglects the effect of fountain flow at the flow front. In addition, crystallization is considered in the simulation of a birefringence profile for semicrystalline polymer like PP [7]. Although such simplification is often used in the flow analysis of actual injection‐molded parts [8], there is another method for a fundamentally simple flow path.…”

Section: Introductionmentioning

confidence: 99%

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Viscoelastic flow analysis of surface morphology on injection‐molded polypropylene

Kobayashi

Otsuki²,

Kanai

2010

Polymer Engineering & Sci

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The molecular orientation of a frozen layer in an injection‐molded specimen of a polypropylene–rubber blend was investigated. A typical V‐shaped pattern of birefringence was observed from the surface to the core in a crosscut section. From the comparison of the V‐patterns near the gate to the flow end, it was assumed that a frozen layer formed from the surface to a depth of 0.06 mm in a plaque (3 mm thickness) during the injection molding filling process. Numerical viscoelastic analysis of the fountain flow was carried out using an original 2D unsteady flow simulation program and ignored crystallization. A large extensional deformation formed just when the molten polymer contacted the cavity wall and the deformation immediately froze. A layer with a small birefringence between the surface and the shear‐oriented layer was divided into two parts. The depth profile of birefringence was compared to the principal stress difference calculated by numerical analysis. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Viscoelastic flow analysis of surface morphology on injection‐molded polypropylene

Kobayashi

Otsuki²,

Kanai

2010

Polymer Engineering & Sci

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“…Birefringence is a measurement of the total molecular orientation of both crystalline and amorphous region in a semicrystalline polymer such as PBS [26][27][28]. It is able to provide a quantitative measurement on the overall molecular orientation by detecting the differences in polarizability of molecular chains at two perpendicular directions [29]. Figure 6 shows the birefringence, !n as a function of !.…”

Section: Microwave Molecular Orientation Analysismentioning

confidence: 99%

Mechanical properties and structure development in poly(butylene succinate)/organo-montmorillonite nanocomposites under uniaxial cold rolling

Phua¹,

Chow²,

Ishak³

2011

Express Polym. Lett.

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Abstract. Polymer nanocomposites have potentially enhanced properties when the molecular orientations of the polymer chains can be controlled. In this study, the mechanical and structural properties of poly(butylene succinate) (PBS) and 2wt% organo-montmorillonite (OMMT) filled PBS nanocomposites were modified by uniaxial cold rolling. Cold rolling was carried out to different compression ratios. The mechanical properties of rolled samples were studied in both the machine direction (MD) and the transverse direction (TD). Along the MD, distinct improvements in tensile strength and elongation at break were observed. However, the tensile strength degraded along the TD. Wide angle X-ray diffraction (WAXD) and microwave molecular orientation analysis reported on the degree of molecular orientation after rolling. Further, degree of crystallinity was reduced after cold rolling.

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“…Using the calculated K(T) and assuming n equal to 3, the differential form of the Nakamura equation 10 , given by Equation 7, can be used to simulate the dθ/dt vs. T curves, which are integrated to obtain almost exclusively to the Nakamura equation, mostly in Isayev's various scientific works [6][7][8][9] . In this respect, nonlinear regression is more flexible; moreover, it can be applied to other types of equation, not only to those that fit into the form of Equation 1.…”

Section: Abstract: Master Curve Approach Non-isothermal Crystallizatmentioning

confidence: 99%

Determination of non-isothermal crystallization rate constant for pseudo-experimental calorimetric data

2009

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Modeling and experimental study of birefringence in injection molding of semicrystalline polymers

Cited by 24 publications

References 39 publications

Viscoelastic flow analysis of surface morphology on injection‐molded polypropylene

Viscoelastic flow analysis of surface morphology on injection‐molded polypropylene

Mechanical properties and structure development in poly(butylene succinate)/organo-montmorillonite nanocomposites under uniaxial cold rolling

Determination of non-isothermal crystallization rate constant for pseudo-experimental calorimetric data

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