Application of digital image analysis to pattern formation in polymer systems

Tanaka, Hajime; Hayashi, Takafumi; Nishi, Toshio

doi:10.1063/1.336795

Cited by 129 publications

(99 citation statements)

References 1 publication

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“…The periodicity of the ring is about 25 µm. The spherulitic ringed pattern has also been reported for poly(vinyl chloride) (PVC)/poly(e-caprolactone) (PCL) 20 and poly(vinylidene floride) (PVF 2 )/poly(methyl methacrylate) (PMMA) blends, 21 • 22 while such a pattern did not appear for the pure crystalline component of these blends. Because the ringed pattern is associated with the spatial twisting of lamellae, the appearance of such a pattern in PLLA/PEG blends may indicate that the presence of PEG has altered the aggregation and twistings of PLLA lamellae.…”

Section: Resultsmentioning

confidence: 94%

Miscibility and Crystallization of Poly(L-lactide)/Poly(ethylene glycol) and Poly(L-lactide)/Poly(ε-caprolactone) Blends

Yang

Chen

You

et al. 1997

Polym J

162

111

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ABSTRACT:The miscibility and crystallization behavior of two binary blends, poly(L-lactide) (PLLA)/poly(ethylene glycol) (PEG) and PLLA/poly(e-caprolactone) (PCL), with PLLA as the main component (PLLA composition was not lower than 50wt%) have been investigated by differential scanning calorimetry (DSC) and optical microscopy. PEG and PCL with moderate molecular weight (MW"" 10000) were used as the blending components for PLLA. PLLA and PEG were miscible in the melt over the composition range investigated. The variation of the bulk crystallization rate of PLLA with PEG composition displayed a maximum at IO wt% PEG. On the other hand, a monotonic increase in spherulite growth rate with increasing PEG composition was observed. Since the bulk crystallization rate is determined by both the nucleation density and the growth rate, the depression of nucleation density coupled with the increase of growth rate with increasing PEG composition may give rise to the observed maximum in the composition variation of the bulk crystallization rate. The crystallizability of PLLA and PEG in the blends was also evaluated. The crystallizability of PEG was reduced by blending with PLLA, while that of PLLA was essentially unaffected by blending with PEG. For the PLLA/PCL system, a phase-separated morphology was identified in the melt. However, the crystallization rate of PLLA could be enhanced upon blending with PCL. Since no preferential nucleation at the domain interface was observed, the promotion of PLLA crystallization rate was attributed to its partial miscibility with PCL.KEY WORDS Poly(L-lactide) / Poly(ethylene glycol) / Poly(e-caprolactone) / Blends / Miscibility / Crystallization Behavior / Biodegradable polymers have attracted increasing attention due to their potential applications as biomedical and environment-friendly materials. In addition to mechanical and thermal properties, the rate and extent of degradation are the essential considerations for biodegradable polymers. The degradation behavior of biodegradable polymers has been frequently controlled by modifying the chemical or stereochemical compositions of the polymers. 1 -5 Copolymerization, for example, is a popular method for such a modification, 1 • 2 • 5 Besides the chemical nature, the morphology of a biodegradable polymer may also be an influential factor on its degradation behavior. For example, when a semicrystalline biodegradable polymer is subjected to a degradation medium such as water and enzyme, the molecules of the medium would enter into the amorphous regions more easily than into the crystalline regions. The degradation rate will then depend on the degree of crystallinity and the chain packing in the amorphous regions, which are determined by the thermal history and the molecular weight. Therefore, morphological controls through thermal history and molecular weight variations, physical aging, and chain orientation may also be useful for controlling the degradation behavior of a biodegradable polymer. crystallizability and the morphology of biodegr...

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Section: Resultsmentioning

confidence: 94%

Miscibility and Crystallization of Poly(L-lactide)/Poly(ethylene glycol) and Poly(L-lactide)/Poly(ε-caprolactone) Blends

Yang

Chen

You

et al. 1997

Polym J

162

111

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“…The structure factor offers direct comparison with light scattering experiments because it is proportional to the scattering intensity. 46 A similarly useful quantity is the pair correlation function, G p (r, t), which is the Fourier transform of S(k, t)…”

Section: Computational Resultsmentioning

confidence: 99%

Kinetics of thermally induced phase separation in ternary polymer solutions. I. Modeling of phase separation dynamics

Barton¹,

McHugh²

1999

J. Polym. Sci. B Polym. Phys.

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“…The normal practice to simulate light scattering profiles is to Fourier transform a discretized two dimensional image of what could be observed by, for example, phase contrast microscopy 6) . This procedure is also used when the image is synthetically generated by, for instance, the Cahn-Hilliard theory when the phase separation phenomenon is due to SD 7,8) .…”

Section: Introductionmentioning

confidence: 99%

Light scattering of phase separated systems by nucleation-growth mechanisms: a model based on the Fast Fourier Transform

Eliçabe¹

1999

Macromol. Theory Simul.

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SUMMARY: The problem of simulating light scattering patterns of polymerization induced phase separation processes by the mechanism of nucleation and growth is addressed with the objective of reducing the number of computations required to carry out the simulation. A method, based on the Fast Fourier Transform (FFT), that takes advantage of the spherical nature of the phase separated domains, is proposed. Contrary to the case in which the spherical particles are randomly placed in arbitrary locations in the scattering volume, the proposed computational scheme requires the locations not to be arbitrary but to belong to a previously defined equally spaced grid. This last constraint determines levels of resolution in which the simulation can be performed. The FFT based method is tested with a morphology previously generated with a model of the phase separation process. The light scattering pattern corresponding to this morphology, mainly represented through the particle size distribution of the spherical separated domains, has been simulated at different levels of resolution of the grid placed in the scattering domain and of the sizes of the domains. It has been found that the original morphology represented by a distribution with 17 different sizes can be approximated by a smaller number, while keeping the total volume of particles the same, without a noticeable loss of precision. This, together with the fact that the computations can be performed at different levels of resolution, gives the chance to explore an important number of approximations to the problem, many of which produce, using the proposed method, results that are comparable to those obtained at higher levels of resolution, with the advantage of requiring a smaller number of computations.

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Application of digital image analysis to pattern formation in polymer systems

Cited by 129 publications

References 1 publication

Miscibility and Crystallization of Poly(L-lactide)/Poly(ethylene glycol) and Poly(L-lactide)/Poly(ε-caprolactone) Blends

Miscibility and Crystallization of Poly(L-lactide)/Poly(ethylene glycol) and Poly(L-lactide)/Poly(ε-caprolactone) Blends

Kinetics of thermally induced phase separation in ternary polymer solutions. I. Modeling of phase separation dynamics

Light scattering of phase separated systems by nucleation-growth mechanisms: a model based on the Fast Fourier Transform

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