Miscibility, crystallization and melting behaviour, and morphology of binary blends of polycaprolactone with styrene-co-maleic anhydride copolymers (original) (raw)
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Polymer, 1994
The morphology of polymer blends of poly(e-caprolactone) (PCL) and poly(vinyl methyl ether) (PVME) is compared with that of PCL and a random copolymer of styrene and acrylonitrile (SAN). The main objective is to determine the influence of the glass transition temperature of the amorphous component (TB,,) on the morphology of the semicrystalline polymer blends. These blends represent the two extreme cases corresponding to Tc < Ts,a and Tc > Tg.,, where Tc is the crystallization temperature. The morphology of these blends, with PVME and SAN representing the amorphous components, have been studied by small angle X-ray scattering. For both blends the long period increases with the addition of amorphous polymer, which is a strong indication for an interlamellar morphology. D.s.c. experiments, including enthalpy relaxation, are used to investigate the crystallinity and the interphases. The overall amount of crystallinity in both blends decreases with increasing content of amorphous polymer. However, the fraction of PCL that crystallizes decreases in PCL/SAN and increases slightly in PCL/PVME. Apparently, the addition of the low T~,, PVME improves the crystallization of PCL in accordance with a simple Gamblers Ruin Model type argument. The high Tg,a of SAN means this does not occur in PCL/SAN blends. Conventional d.s.c. experiments show an interphase of pure amorphous PCL in PCL/SAN blends and enthalpy relaxation experiments demonstrate its presence in PCL/PVME blends as well.
Journal of Polymer Science Part B: Polymer Physics, 1993
The phase separation of a crystalline and miscible polymer blend, poly ( t-caprolactone) / poly (styrene-co-acrylonitrile) (PCL/SAN) , has been studied by differential scanning calorimetry (DSC ) , using a SAN containing 28.3% of acrylonitrile units. Several phenomena can be associated with the occurrence of phase separation depending upon the composition of the mixture. Following annealing at high temperatures, below and above the phase separation temperature T,, three cases can be distinguished. In Case I, there is no sign of crystallization during quenching and DSC scanning, but a melting peak is observed at T, and above. In Case 11, there is no crystallization on quenching but it does occur during the DSC run; the shift of the crystallization peak can then be related to T,. In Case 111, there is crystallization on quenching, and additional crystallization during the DSC run; the change of area of the crystallization peak is indicative of T,. From these observations, the phase diagram of the system was determined. 0 1993 John Wiley & Sons, Inc. Keywords: phase separation of crystalline and miscible polymer blends blends of poly ( ccaprolactone) and poly (styrene-co-acrylonitrile) phase separation of differential scanning calorimetry (DSC) of blends of poly (c-caprolactone) and poly (styrene-co-acrylonitrile) Appl. Polym. Sci., 32,5357 ( 1986).
Journal of Polymers and the Environment
Poly(ε-caprolactone) (PCL) and two different molecular weight (6K and 650K) of polystyrene (PS) were mixed in solution to prepare binary blends of PCL/PS with various compositions. The impact of the molecular weight of PS in the blends was studied on thermal stability and miscibility by the thermogravimetric analysis (TGA) and the differential scanning calorimetry (DSC) method. The TGA results under dynamic conditions in an inert atmosphere show that the thermal stability of the blends depends on the length of PS molecules. The increase of the low molecular weight PS into the PCL/PS blend reduces the thermal stability while the high molecular weight PS improves the thermal stability. The crystallization peak temperature, enthalpy, and crystallinity of the blends are found molecular weight dependent; these parameters with blend compositions deviate from linearity of additive law for low molecular weight PS, while they do follow the additive law for high molecular weight PS. A significant melting point depression of PCL crystals with composition was observed for the blends with the incorporation of the low molecular weight PS, while the no significant melting temperature depression was observed for the high molecular weight PS. The experimental results clearly indicate that in the PCL/PS blends, the thermal stability and the interaction between the neat components strongly depend on the molecular weight of the PS.
Journal of Polymer Science Part B: Polymer Physics, 1998
The miscibility of poly(4-hydroxystyrene-co-methoxystyrene) (HSMS) and poly(e-caprolactone) (PCL) was investigated by differential scanning calorimetry and Fourier transform infrared spectroscopy (FTIR). HSMS/PCL blends were found to be miscible in the whole composition range by detecting only a glass transition temperature ( T g ), for each composition, which could be closely described by the Fox rule. The crystallinity of PCL in the blends was dependent on the T g of the amorphous phase. The greater the HSMS content in the blends, the lower the crystallinity. The polymerpolymer interaction parameter, x 32 , was calculated from melting point depression of PCL using the Nishi-Wang equation. The negative value of x 32 obtained for HSMS/ PCL blends has been compared with the value of x 32 for poly(4-hydroxystyrene) (P4HS)/PCL blends. The specific nature, quantitative analysis, and average strength of the intermolecular interactions in HSMS/PCL and P4HS/PCL blends have been determined at room temperature and in the molten state by means of Fourier transform infrared spectroscopy (FTIR) measurements. The FTIR results have been in good correlation with the thermal behavior of the blends.
Polymer, 1997
The morphology of symmetric diblock copolymer of e-caprolactone (PCL) and trimethylene carbonate (PTMC), in blends with poly(vinyl methyl ether) (PVME) is investigated with (modulated) differential scanning calorimetry (d.s.c.), time resolved small angle (SAXS) and wide angle (WAXS) X-ray spectroscopy and optical microscopy. In the melt the crystallizable block PCL is immiscible with the amorphous PTMC block. PCL is melt miscible with PVME, whereas PTMC and PVME are immiscible. Despite the much higher molecular weight of PVME, the favourable interaction between PVME and PCL results in a microphase separated morphology with PVME residing inside the PCL domains, In the melt, PVME is for up to 20 wt%, almost homogeneously mixed with PCL. Above 20 wt%, PVME partly segregates inside the PCL domains. In all cases, PCL starts to crystallize from a microphase separated melt. During the crystallization a characteristic small angle scattering peak together with the corresponding wide angle peaks develops. The long period of the crystalline morphology increases as a function of the amount of PVME.
Morphologies of Various Polycaprolactone/Polymer Blends in Ultrathin Films
Macromolecules, 2015
Morphologies of ultrathin films of nine poly(εcaprolactone)/polymer miscible and immiscible binary blends have been investigated under isothermal crystallization conditions by real time atomic force microscopy, optical microscopy, and electron diffraction techniques. It was found that the truncated lozenge-shape morphology of the pure poly(ε-caprolactone) (PCL) crystals is modified in miscible blends, forming regular or inverted S-or C-shaped crystals, the curvature depending on the nature of the second polymer and increasing with blend composition. Moreover, the growth rate decreases with the addition of the second polymer following the same order as the crystal curvature: PVC > CPE(48%) > SAN(25%) > PC > SAN(9.5%) > PVME. In contrast, for immiscible blends, no significant changes in kinetics and morphology were observed since a constant crystal growth rate and the same truncated lozenge-shape morphology as pure PCL crystals are obtained at all compositions. Kinetic and morphological changes in miscible blends are discussed in terms of PCL/polymer intermolecular interactions since the growth rate decreases and the curvature increases with the addition of polymers of increasing interactions.
Macromolecules, 1994
The phase behavior and miscibility of poly(c-caprolactone) (PCL)/polycarbonate (PC) blends have been investigated with DSC, cloud-point measurement, TGA, FTIR, NMR, and small-angle neutron scattering (SANS). Thermal analysis results indicated that the PCL-rich blends are semicrystallinel semicrystalline at room temperature. At about 30% PC incorporation, the PCL crystallinity showed amarked reduction, whereas the PC crystallinity approached amaximum. The composition dependence of Tgexhibited a discontinuity (cusp) and was critically analyzed using the classical equations of Gordon-Taylor and Fox and the free volume theory of Braun-Kovace. Combination of the Fox and Braun-Kovace equations accurately reproduced the T,-composition dependence. Thermal stability of the blends, as measured by the onset degradation temperature in air, increased with increasing PC. FTIR results coupled with lSC NMR findings supported the hypothesis that the blends primarily degraded via thermally-induced chain scission of PCL as evidenced by the evolution of COS. SANS studies on the deuterated PC-rich blends revealed that the scattering intensity first remained fairly constant with increasing temperature and then increased sharply at temperatures above the blend Tp The sudden rise in the scattering intensity was attributed to crystallization of PC resulting from prolonged annealing. Results derived from the RPA analysis of the SANS profiles measured at 30 "C for the deuterated PC-rich blends and those obtained from the melting point depression analysis of the PCL-rich blends suggested favorable blend interactions as reflected by the negative sign of the x parameter.
Crystals, 2021
A series of poly(ethylene-co-vinyl alcohol)/poly(ε-caprolactone) blends with different compositions were prepared using solvent casting. The miscibility of this pair of polymers was investigated using differential scanning calorimetry (DSC), and proved by a negative Flory interaction parameter value calculated from the Nishi–Wang equation. The miscibility of this blend was also confirmed by scanning electronic microscopy (SEM). The thermal behaviors of the obtained materials were investigated by DSC, thermogravimetric analysis, and direct analysis in real-time–time-of-flight mass spectrometry and the results obtained were very relevant. Furthermore, the crystalline properties of the obtained materials were studied by DSC and X-ray diffraction where the Ozawa approach was adopted to investigate the non-isothermal crystallization kinetics. The results obtained revealed that this approach described the crystallization process well.