Influence of copolymer composition on the crystallization in PCL/SAN blends

Kreßler, Jörg; Svoboda, Petr; Inoue, Takashi

doi:10.1016/0032-3861(93)90395-q

Cited by 40 publications

(41 citation statements)

References 26 publications

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“…No. 3,1998 electrons scattered from the surface increases and the brightness of the image is therefore much higher. So, it is thought that the contrast difference for these two ring-banded spherulites may be caused by different substructures; one substructure having a relatively less fluctuation surface, which will release less secondary electrons to the detector to yield dark images and the other having a 'wavy' surface, which will release more secondary electrons to the detector to yield bright image.…”

Section: Resultsmentioning

confidence: 99%

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Novel Morphology in Ring-Banded Spherulites from Single-Phase Mixtures of Poly(ε-caprolactone) with Poly(styrene-co-acrylonitrile)

Wang

Jiang

et al. 1998

Polym J

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ABSTRACT:Novel morphology of ring-banded spherulites in the surface of poly(c-caprolactone)/poly(styrene-coacrylonitrile) (PCL/SAN) blends was discovered and studied by SEM and TEM. The ring-banded spherulites separate into those exhibiting a very dark contrast, of relatively regular bundles of lamellae and others appearing with a much brighter intensity, of a coarse and irregular aggregates of lamellae. The origin of the novel morphology is not due to different crystalline structures as in the case of isotactic polypropylene because only one crystal structure exists in PCL/SAN blends. The formation may reflect whether spherulites in PCL/SAN blends are nucleated at the bottom surface or at the top (free) surface.KEY WORDS Poly(E-caprolactone) / Poly(styrene-co-acrylonitrile) / Ring-Banded Spherulite / Morphology/ Polymers undergoing phase transformation show a wide variety of microstructures. The most common growth is termed "spherulitic." This form consists of radial arrays of lamellar crystals. Poly(s-caprolactone) (PCL) is miscible on a molecular level with poly(styreneca-acrylonitrile) (SAN) when copolymer contains from 8 to 28 wt¾ acrylonitrile. 1 When below the melting temperature (Tm) of PCL, PCL lamellae grow (crystallization), and between them, a homogeneous mixture of amorphous PCL and SAN should remain. The crystallization behavior of PCL is strongly influenced when amorphous SAN is present. This leads to ring-banded spherulites. 2 -5 However, to our knowledge, it is not enough, up to now, to investigate the morphology of ring-banded spherulites formed in PCL/SAN blends or the mixtures of PCL with other polymers by electron microscope. 2 -12 This paper studies novel spherulitic morphology on the surface of ring-banded spherulites generated in PCL/SAN blends. A possible formation mechanism of two types of ring-banded spherulites is discussed. EXPERIMENT ALPCL was purchased from Polysciences Inc. (U.S.A.). M w and Mn determined by gel permeation chromatography (GPC) are 22000 and 11300, respectively. The melting temperature of PCL is about 60°C from differential scanning calorometry (DSC) measurement. SAN with 25 wt¾ acrylonitrile (AN) content was supplied by Polysciences Inc. The Mw and Mn are 197000 and 106000 by GPC, respectively. Tg of SAN is about 105°C measured by DSC. Samples of PCL and PCL/SAN (90/10) blends were prepared by mixing in CH 2 Cl 2 . A dilute solution (5% wt/wt) was stirred continuously for 24 h at 25°C. The thin films were cast on a clean cover glass 1 To whom correspondence should be addressed. 206and held in a vacuum oven at 40°C for three days. The isothermal crystallization of PCL and PCL/SAN blends was performed on two home-made optical microscope hot stages, in which temperature was controlled within ± 0.1 °C. The films with a free surface upwards were first melted on one hot stage at 80°C for 5 h, then rapidly transported to another hot stage controlled at crystallization temperature (Tc) of 35°C and maintained for 24h.After crystallization, the films without surface treatm...

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Section: Resultsmentioning

confidence: 99%

“…30, No. 3,1998 crystalline structures, such as a-or /3-spherulites as in the case of isotactic polypropylene. The differences between the two spherulites may reflect whether spherulites are nucleated at the bottom or top (free) surface.…”

Section: Discussionmentioning

confidence: 99%

Novel Morphology in Ring-Banded Spherulites from Single-Phase Mixtures of Poly(ε-caprolactone) with Poly(styrene-co-acrylonitrile)

Wang

Jiang

et al. 1998

Polym J

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“…Poly(e-caprolactone) (PCL) is a semicrystalline polyester which crystallizes readily in bulk and in blends [12]. A comprehensive study of the crystallization of medium-and highmolar-mass PCL on the water surface was done by Esker et al including Langmuir trough studies, BAM, and after LangmuirBlodgett (LB) transfer onto solid substrates atomic force microscopy (AFM) and electron diffraction studies [13].…”

Section: Introductionmentioning

confidence: 99%

Polymer Crystallization on the Surface of Water or Aqueous Salt Solution

et al. 2016

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The crystallization of two semicrystalline and water-insoluble polymers with ester moieties, namely poly(e-caprolactone) (PCL) and isotactic poly(methyl methacrylate) (i-PMMA), was studied on the water surface using Langmuir trough measurements and Brewster angle microscopy. Additionally, Langmuir-Blodgett films were prepared and examined by atomic force microscopy. It was demonstrated that PCL forms distinct single crystals on the water surface with polymer chain orientation perpendicular to the water surface. i-PMMA behaved differently and crystallized upon compression on the water surface in a homogeneous layer with polymer chain orientation parallel to the water surface. In contrast, poly(ethylene oxide) (PEO) is a water-soluble polyether and its crystallization at the air/liquid interface could only be studied when the water subphase was replaced with aqueous salt solutions containing kosmotropic salts according to the Hofmeister series.

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“…[3,8 -14] It was found that crystallization of the semicrystalline polymer was induced by the nucleation effect [3,10] of the modulated structure or the concentration fluctuation [11,12] during the liquid -liquid phase separation. However, in poly(1-caprolactone) (PCL) and SAN mixtures, [9] the crystallization rate was impeded because the mobility of the PCL chains decreased in the presence of SAN. Tanaka et al [5] found that polystyrene was rejected from the PCL crystal and piled up in the interlamellar region after the mixture was annealed at 508C near the binodal line.…”

Section: Introductionmentioning

confidence: 99%

Thermal Behavior of Polyamide‐12 and Poly (Styrene‐Co‐Acrylonitrile) Blend

Sun

Huang

Yang

et al. 2006

Journal of Macromolecular Science, Part B

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In this work, an unusual morphology of a mixture of polyamide-12 (PA-12) with a series of poly (styrene-co-acrylonitrile) (SAN) was obtained by solution casting and fast solvent evaporation. The prepared film was transparent although it contained many crystals. These crystals apparently prevented phase separation despite the instability of the PA-12 and SAN mixtures below 1808C. In isothermal experiments, once the crystals were melted, phase separation began and the scattered intensity fit the Cahn-Hilliard theory. When the AN content in the SAN copolymer was less than 5%, the phase separation took place when only part of the crystals were melted at 1808C. However, due to the constraint of unmelted crystals, the growth rate of phase separation at this temperature was much slower.

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Influence of copolymer composition on the crystallization in PCL/SAN blends

Cited by 40 publications

References 26 publications

Novel Morphology in Ring-Banded Spherulites from Single-Phase Mixtures of Poly(ε-caprolactone) with Poly(styrene-co-acrylonitrile)

Novel Morphology in Ring-Banded Spherulites from Single-Phase Mixtures of Poly(ε-caprolactone) with Poly(styrene-co-acrylonitrile)

Polymer Crystallization on the Surface of Water or Aqueous Salt Solution

Thermal Behavior of Polyamide‐12 and Poly (Styrene‐Co‐Acrylonitrile) Blend

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