Ternary blends of phenoxy/SAN/poly(-ε-caprolactone)

The compatibilizing effect of poly(ε-caprolactone) (PCL) on the blends of two immiscible polymers, poly(hydroxy ether of bisphenol A) (phenoxy) and poly(styrene-co-acrylonitrile) (SAN) has been investigated. The phase behavior of the ternary blends was affected by the AN content in the SAN copolymers and a maximum miscible region was observed at 19.5 wt % of AN. The effect of AN content on the phase behavior of the ternary blends was interpreted in terms of the relative magnitude of the segmental interaction energy densities, which were obtained by combining a melting point depression and an extended binary interaction model. When a small amount of PCL was added to the phenoxy/SAN blends, the phase morphology showed a finer phase dispersion, indicating that the interfacial tension between the phenoxy and SAN is considerably reduced. However, the improvement in tensile properties was limited despite the morphological change with the PCL content. From the results of the DSC measurements, SEM, and tensile testing, it was understood that the PCL acted as a compatibilizer for the immiscible phenoxy/SAN blends. © 1994 John Wiley & Sons, Inc.     

SAN共聚物组成对PVC/ABS共混物相容性的影响

采用乳液聚合技术通过改变共聚单体的投料比(St/AN)合成了一系列不同AN结合量的ABS接枝共聚物粉料和SAN共聚物.将其与聚氯乙烯(PVC)和邻苯二甲酸二辛酯(DOP)熔融共混分别制得了PVC/ABS、PVC/SAN、PVC/ABS/DOP和PVC/SAN/DOP共混物,利用SEM、TEM和动态力学粘弹谱仪(DMA)对共混物的相容性和相结构进行了表征.结果发现,在PVC/ABS共混体系中,尽管改变接枝SAN共聚物的AN结合量,PVC和SAN共聚物均为不相容体系;在该共混物中引入增塑剂DOP后,虽然当SAN共聚物AN结合量小于23.4 wt%时,共混物在室温以上只存在一个tanδ峰,但形态结构研究结果表明共混物仍为不相容体系,共混物的相区尺寸明显地依赖于SAN共聚物中的AN结合量,当AN结合量为23.4 wt%时相区尺寸最小.     

Miscibility and Mechanical Behavior of SAN/NBR Blends

Summary: Aiming the development of high toughness polymer materials, blends of poly(styrene-co-acrylonitrile) (SAN) and poly(butadiene-co-acrylonitrile) (NBR) rubbers, with contents of acrylonitrile (AN) varying from 21 to 45%, were prepared by casting, coprecipitation and monoscrew extrusion followed by injection molding. SAN/NBR blends, prepared in the compositions (w/w) 90/10, 80/20, 70/30, 60/40, and 50/50, were characterized by differential scanning calorimetry (DSC) and Izod impact tests. DSC analyses showed that blends with 33% AN NBR prepared by casting, and with 39% AN NBR prepared by coprecipitation, are partially miscible at 60/40, 70/30 and 80/20 (SAN/NBR) compositions and immiscible for 50/50 compositions. On the other hand, 90/10 SAN/NBR systems were totally miscible. The blends with 45% AN NBR prepared by coprecipitation showed partial miscibility to 50/50, 60/40, 70/30 and 90/10 compositions and total miscibility to 80/20 composition. The NBR addition results in a significant increase in the impact resistance, strongly dependent on the blend composition and the NBR AN content. The best result of impact resistance — 75.2 ± 8.6 (kJ · m⁻²) — was obtained for SAN/NBR 50/50, using 45% AN NBR. This value is 15.7 times bigger than that for pure SAN -4.8 ± 0.7 (kJ · m⁻²).     

Ringed spherulites in ternary polymer blends of poly(<Emphasis Type="Italic">ε</Emphasis>-caprolactone), poly(styrene-<Emphasis Type="Italic">co</Emphasis>-acrylonitrile), and polymethacrylate

The relationship between ringed spherulite morphology, crystallization regimes/kinetics, and molecular interactions in miscible ternary blends of poly(-caprolactone) (PCL), poly(benzyl methacrylate) (PBzMA), and poly(styrene-co-acrylonitrile) (SAN) was investigated by using differential scanning calorimetry (DSC), polarized optical microscopy (POM), and wide-angle X-ray diffraction (WAXD). The interactions resulted in the deviation of both experimental and calculated T_gs and formation of the specific morphology of the spherulitic structure. Ring-banded spherulites were observed in the PCL/PBzMA/SAN ternary blends. The width of ring bands changed with the blend ratio and the crystallization temperature. Additionally, both composition and wt% of AN in the SAN copolymer had an apparent effect on the morphology of PCL spherulites. Both the crystallization structure of lamellae and molecular interactions greatly influenced the ring bands of PCL spherulites. Furthermore, by using the Flory–Huggins approximation, the depression of the melting point showed that interactions in the PCL/PBzMA/SAN-17 blend were greater than in the PCL/PBzMA/SAN-25 blend. In the ternary blends, the great molecular interactions between amorphous and crystalline polymer resulted in better homogeneity and a larger band period of the extinction rings in the PCL spherulites.     

Crystallization behavior and hydrophilicity of poly (vinylidene fluoride) (PVDF)/poly (styrene-<Emphasis Type="Italic">co</Emphasis>-acrylonitrile) (SAN) blends

Poly (styrene-co-acrylonitrile) (SAN) is a hydrophilic non-crystalline copolymer, which is initially used in this paper to improve the hydrophilicity of poly (vinylidene fluoride) (PVDF). Investigation of the crystallization behavior of PVDF/SAN blends showed that the samples presented only α phase regardless of SAN content as cooling from the melt. A double-melting phenomenon was related to the perfection or crystal size of PVDF crystals. As the SAN content is increasing, crystallization of PVDF was limited, leading to a decreased crystallinity and lamellar growth. Besides, the hydrophilicity of PVDF was improved by blending with SAN. The sample containing 70 wt.% SAN performed a similar surface property of the neat SAN owing to the besieging of the PVDF phase by SAN. Observed from the cross section of the blends, PVDF/SAN blends were partially miscible with less than 50 wt.% SAN addition. As the SAN content was more than 50 wt.%, the crystalline PVDF particles clearly dispersed in the amorphous matrix.     

Transition from miscibility to immiscibility in blends of poly(methyl methacrylate) and styrene-acrylonitrile copolymers with varying copolymer composition: a DSC study

The glass transition and the structural relaxation processes have been studied in blends of poly(methyl methacrylate) (PMMA) and styrene-acrylonitrile (SAN) copolymers with different acrylonitrile (AN) contents. The 50/50 wt.% blend of PMMA with the SAN copolymer containing 30 wt.% of AN is immiscible, while blends with copolymers containing between 13 and 26 wt.% of AN are miscible. Thus the upper limit of miscibility is between 26 and 30 wt.% of AN. The temperature dependence of the relaxation times of the conformational rearrangements of polymer chains around the glass transition have been determined in the blends and pure components by modelling DSC thermograms obtained after different thermal histories in each sample. The slope in the Arrhenius diagram logτ vs 1/T around the glass transition temperature is significantly smaller in the blend which is closer to the upper limit of miscibility than in the other miscible blends in which SAN copolymer contains less AN. The change of slope can be ascribed to a distribution in the glass transition temperatures of the different rearranging regions, reflecting the appearance of a microheterogeneity in the blend that cannot be detected as a double glass transition in the blend.     

电子束辐照法制备交联共混物聚(ε-己内酯)/苯乙烯-丙烯腈共聚物的结晶动力学研究

将线形聚(ε-己内酯)(PCL)、苯乙烯-丙烯腈共聚物(SAN)和三烯丙基异三聚氰酸酯(TAIC)熔融共混,通过电子束辐照法制备了3组凝胶含量不同的交联PCL和PCL/SAN共混物样品.采用相差显微镜(PCOM)观察发现PCL与SAN具有良好的相容性.利用示差扫描量热法(DSC)和偏光显微镜(POM)研究了交联PCL和PCL/SAN共混物的等温结晶动力学和非等温结晶行为.结果表明,当体系交联程度相近时,交联聚己内酯的结晶动力学随SAN含量的增加而明显减慢.在SAN含量相同时,交联聚己内酯的结晶速率随交联程度增大而减小.对分离提取的线形和交联组分进行结晶动力学的研究则表明SAN引入对PCL的结晶速率起到了关键性的抑制作用.     

Structure-properties correlations in poly(ε-caprolactone)/poly(styrene-co-acrylonitrile)/nanosilica mixtures: Interrelationship among phase behavior,morphology and non-isothermal crystallization kinetics

In this work, the effects of amorphous poly(styrene-co-acrylonitrile) (SAN) chains and hydrophilic and hydrophobic nanosilica at different loadings on the non-isothermal crystallization kinetics of PCL phase have been evaluated using different theoretical models including Avrami, modified Avrami, Ozawa and Mo equations. Using microscopic observations, the interrelations among the changes in the kinetics parameters and the morphology and phase behavior of PCL/SAN and PCL/SAN/nanosilica mixtures have been thoroughly investigated. Microscopic observations on the nanocomposites showed differences in the nanofiller dispersion and distribution state as well as preferential migration and localization state. These differences lead to contradictory trends in the effects of hydrophilic and hydrophobic nanosilica on the crystallization kinetics of pure PCL and PCL/SAN blends. The nanoparticle migration during non-isothermal DSC tests in PCL/SAN blends, the formation of nanoparticle agglomerates at higher loadings, the restrictions imposed on the molecular movements in the crystallization growth stage and slower phase separation and dissolution of PCL/SAN/silica mixtures result in the cooling rate dependence of the kinetics parameters.     

Miscibility of polycaprolactone/chlorinated polyethylene blends

Blends of polycaprolactone (PCL) with chlorinated polyethylenes (PECls) having chlorine contents of 25, 30, 36, 42, and 48% by weight were prepared and studied by differential scanning calorimetry and small-angle light scattering (SALS). It was found that blends made with PECls containing 30% or more chlorine are completely miscible with PCL (a single glass transition temperature T_g is found) while the PCL/PECl(25) blends are immiscible. PCL crystallizes in the miscible blends at any composition and it has an enthalpy of fusion which decreases only slightly with PECl content. Blends in the PECl composition interval of 0–80% are spherulitic, as shown by SALS, but a rodlike morphology is found at the 85% composition and dispersed crystals are observed at higher compositions. It is suggested that the k parameter of the Gordon-Taylor equation can be taken as a measure of the strength of the specific interaction between PCL and PECl. Low values of k (0.26 and 0.35) are found for PCL/PECl blends but a higher value of k (0.51) has been reported for PCL/poly(vinyl chloride) (PVC) blends, indicating a stronger interaction in the latter mixtures. In agreement with these findings poly(α-methyl-α-n-propyl-β-propiolactone) and poly(valerolactone) are not miscible with PECl, whereas they were previously shown to be miscible with PVC.     

Nano/micro-scale morphologies of semi-interpenetrating poly(ε−caprolactone)/tung oil polymer networks: Isothermal and non−isothermal crystallization kinetics

The isothermal and non-isothermal crystallization kinetics of pure poly(ε−caprolactone) (PCL) and its blends with crosslinked tung oil were investigated as a function of composition, crystallization temperature, and heating rate using differential scanning calorimetric (DSC). The PCL/tung oil semi-interpenetrating polymer networks of different compositions were prepared via cationic polymerization of tung oil in the presence of homogenous solutions of PCL. This unique and relatively new in-situ polymerization and compatibilization blending technique created nano/micro-scale morphologies that cannot be obtained with the traditional melt-processing and/or solvent casting methods. Blends with different miscibility, phase behaviors, and morphologies (miscible, partially miscible, and immiscible) were observed as a function of composition with a constant concentration of boron trifluoride diethyl etherate (BFE) cationic initiator. The morphology of the semi-interpenetrating polymer networks was performed using scanning electron microscopy (SEM). Miscible blends with a single T_g for PCL ≤ 10 wt.%. were observed. While, on the other hand, partially miscible blends with two distinct T_gs and nanoscale morphologies and average particle sizes as small as 100 nm were observed for blends with 20 ≤ PCL wt.% ≤ 30. Immiscible blends with microscale highly interconnected, co-continuous two-phase morphology and two distinct T_gs were detected for 50 wt.% PCL. Both isothermal and non-isothermal crystallization kinetics were strongly influenced by the different miscibility and morphology of the blends. The isothermal and non-isothermal crystallization kinetics of PCL/tung oil blends were analyzed on the basis of Avrami and modified Avrami approaches, respectively. A substantial decrease in the isothermal (longer half time) and non-isothermal (T_m shifted to lower temperature) crystallization kinetics was observed as the concentration of PCL increased in the blends up to 30 wt.% due to the partially miscibility of the blends in this composition range. In a contrast, for 50 wt.% PCL blend, a considerable increase in the crystallization kinetics (isothermal and non-isothermal) was detected due to the highly interconnected, co-continuous two-phase morphology.     

Crystallization behavior and hydrophilicity of poly(vinylidene fluoride) (PVDF)/poly(methylmethacrylate) (PMMA)/poly(styrene-<Emphasis Type="Italic">co</Emphasis>-acrylonitrile) (SAN) ternary blends

Compatibilization of the partially miscible poly(vinylidene fluoride) (PVDF)/poly(styrene-co-acrylonitrile) (SAN) pair by a third homopolymer, i.e., poly(methyl methacrylate) (PMMA), was investigated in relation to cross section morphology, crystallization behaviors and hydrophilicity of the polyblends. Scanning electron microscopy showed a more regular and homogeneous morphology when more than 15 wt.% PMMA was incorporated. The samples presented only α phase regardless of PMMA content in the blend. As the PMMA content increased in the blends, the interactions between each component were enhanced, and the crystallization of PVDF was limited, leading to a decreasing of the crystallinity and the crystallite thickness. Besides, the hydrophilicity of PVDF was further improved by PMMA addition. The sample containing 15 wt.% PMMA showed a more hydrophilic property due to the more polar part of surface tension induced by PMMA addition. Observed from the cross section of the blends, the miscibility of partially miscible PVDF/SAN blends were efficiently improved by PMMA incorporation.     

Evaluation of the interaction parameter for poly(ε‐caprolactone)/poly(styrene‐co‐acrylonitrile) blends

In this article, the miscibility of poly(ε‐caprolactone) (PCL) with poly(styrene‐co‐acrylonitrile) (SAN) containing 25 wt % of acrylonitrile is studied from both a qualitative and a quantitative point of view. The evidences coming from thermal analysis (differential scanning calorimetry) demonstrate that PCL and SAN are miscible in the whole range of composition. The Flory interaction parameter χ_1,2 was calculated by the Patterson approximation and the melting point depression of the crystalline phase in the blends; in both cases, negative values of χ_1,2 were found, confirming that the system is miscible. The interaction parameter evaluated within the framework of the mean field theory demonstrates that the miscibility of PCL/SAN blends is due to the repulsive interaction between the styrene and acrylonitrile segments in SAN. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010     

Phase behavior,crystallization, and morphology in thermosetting blends of a biodegradable poly(ethylene glycol)‐type epoxy resin and poly(ϵ‐caprolactone)

Thermosetting blends of a biodegradable poly(ethylene glycol)‐type epoxy resin (PEG‐ER) and poly(?‐caprolactone) (PCL) were prepared via an in situ curing reaction of poly(ethylene glycol) diglycidyl ether (PEGDGE) and maleic anhydride (MAH) in the presence of PCL. The miscibility, phase behavior, crystallization, and morphology of these blends were investigated. The uncured PCL/PEGDGE blends were miscible, mainly because of the entropic contribution, as the molecular weight of PEGDGE was very low. The crystallization and melting behavior of both PCL and the poly(ethylene glycol) (PEG) segment of PEGDGE were less affected in the uncured PCL/PEGDGE blends because of the very close glass‐transition temperatures of PCL and PEGDGE. However, the cured PCL/PEG‐ER blends were immiscible and exhibited two separate glass transitions, as revealed by differential scanning calorimetry and dynamic mechanical analysis. There existed two phases in the cured PCL/PEG‐ER blends, that is, a PCL‐rich phase and a PEG‐ER crosslinked phase composed of an MAH‐cured PEGDGE network. The crystallization of PCL was slightly enhanced in the cured blends because of the phase‐separated nature; meanwhile, the PEG segment was highly restricted in the crosslinked network and was noncrystallizable in the cured blends. The phase structure and morphology of the cured PCL/PEG‐ER blends were examined with scanning electron microscopy; a variety of phase morphologies were observed that depended on the blend composition. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2833–2843, 2004     

Crystallization behaviors of poly(3-hydroxybutyrate) and poly(l-lactic acid) in their immiscible and miscible blends

By adjusting the molecular weight of the poly(l-lactic acid) (PLLA) component in poly(3-hydroxybutyrate) (PHB)/PLLA blends, we investigated the crystallization behaviors of the two components in their immiscible and miscible 50:50 blends by real time infrared (IR) spectroscopy. In the immiscible PHB/PLLA blend, the stepwise crystallization of PHB and PLLA was realized at different crystallization temperatures. PLLA crystallizes first at a higher temperature (120 degrees C). Its crystallization mechanism from the immiscible PHB/PLLA melt is not affected by the presence of the PHB component, while its crystallization rate is substantially depressed. Subsequently, in the presence of crystallized PLLA, the isothermal melt-crystallization of PHB takes place at a lower temperature (90 degrees C). It is interesting to find that there are two growth stages for PHB. At the early stage of the growth period, the Avrami exponent is 5.0, which is unusually high, while in the late stage, it is 2.5, which is very close to the reported value (n approximately 2.5) for the neat PHB system. In contrast to the stepwise crystallization of PHB and PLLA in the immiscible blends, the almost simultaneous crystallization of PHB and PLLA in the miscible 50:50 blend was observed at the same crystallization temperature (110 degrees C). Detailed dynamic analysis by IR spectroscopy has disclosed that, even in such apparently simultaneous crystallization, the crystallization of PLLA actually occurs faster than that of PHB. It has been found that, both in the immiscible and miscible blends, the crystallization dynamics of PHB are heavily affected by the presence of crystallized PLLA.     

Structure and properties for binary blends of isotactic-polypropylene with ethylene-α-olefin copolymer. 1. Crystallization and morphology

Morphology and isothermal growth rates of spherulites for the binary blends consisting of an isotactic polypropylene (i-PP) and an ethylene-1-hexene rubber (EHR) were examined as a function of the crystallization temperature ranging from 388 K to 418 K. In this study, two types of EHR's were employed: “ethylene rich” EHR and “1-hexene rich” EHR. The blends of i-PP with the EHR of 51 mol % 1-hexene are miscible in the molten state, whereas the blends with the EHR of 33 mol % 1-hexene are immiscible in the molten state. It is found that the isothermal spherulite growth rate of the miscible i-PP/EHR blends decreases with increasing the EHR fraction, whereas the spherulite growth rate of the immiscible i-PP/EHR blends is independent of the blend composition and is the same as that of the i-PP. Optical microscope observation of the miscible blends crystallized isothermally shows that there are no rubber domains either in the intraspherulitic or in the interspherulitic contact regions. On the other hand, the immiscible i-PP/EHR blends show a phase-separated morphology. Furthermore, the number of tangential lamellae of the miscible i-PP/EHR blends is found to be increased by blending of the EHR, leading to the spherulite with negative birefringence. The sign of birefringence of spherulites is unaffected by the regime transition as well as by the fold surface free energy. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35 : 953–961, 1997     

Fractional crystallization behavior of PCL and PEG in blends

The crystallization behavior of poly(e-caprolactone)/poly(ethylene glycol) (PCL/PEG) blend was investigated by differential scanning calorimetry (DSC) and polarized microscopy (POM). Individual phase transition peaks in the DSC curves for both PEG and PCL in all the polymer blends with different PCL contents were observed. The crystallization and melting peak temperatures of PEG were at 41 and 65°C, respectively; while the crystallization and melting temperatures of PCL located at 28 and 56°C, respectively. In-situ POM results demonstrated that spherulites crystalline morphology was formed for both PCL and PEG homopolymers. In PEG/PCL blend, however, both the phase separation morphology and spherulitic morphology can be observed. In blends with 30 or 50 wt % PCL, the PCL component formed dispersed phase and crystallized at lower temperature. However, in blends with 70% PCL, the phase inversion behavior occurred. The continuous PCL phase crystallized at 35°C, while the PEG dispersed phase crystallized at a lower temperature. Fractional crystallization behavior of PEG and PCL was controlled by temperature. The spherulites growth rate of PEG was greatly influenced by temperature, instead of the content of PCL component in the PCL/PEG blends.     

Growth regimes and spherulites in thin-film poly(ɛ-caprolactone) with amorphous polymers

Spherulite ring-band patterns and growth regimes in neat poly(?-caprolactone) (PCL) and its miscible blends were analyzed using polarized-light optical microscopy and differential scanning calorimetry (DSC). Spherulite growth in thin-film forms and transformation of spherulite patterns in different regimes were investigated by comparing neat PCL with its miscible blends. Three miscible diluents in PCL were probed: poly(p-vinyl phenol) (PVPh), poly(benzyl methacrylate) (PBzMA), and poly(phenyl methacrylate) (PPhMA), which represent strong H-bonding and weak polar interactions, respectively. Blending of PCL with miscible amorphous polymers changes the spherulite patterns significantly. The effect of different diluent polymers varies. Inclusion of different amorphous polymers in PCL leads to different extents of suppression in growth rates and induces different spherulitic patterns. The H-bonding interaction leads to that the PCL/PVPh blend shows dendritic crystals and no ring bands. Although PPhMA differs from PBZMA only by a methylene in the chemical structure of repeat unit, the coil-like textures of ring bands in the PCL/PPhMA blend are widely different from the zig-zag ring bands in the PCL/PBzMA blend. Regime plots show that the growth of neat PCL behaves quite differently from any of its blends with amorphous polymers (PVPh, PPhMA, or PBzMA). Regime plots for PCL/PBzMA blend also differ from those for the PCL/PPhMA blend, which correlates with the crystal patterns seen in these two blend systems.     

Upper critical solution temperature type phase behavior of poly(styrene‐co‐acrylonitrile) blends with poly(styrene‐co‐n‐phenyl maleimide) and their interaction energies

To enhance the heat resistance of poly(styrene‐co‐acrylonitrile‐co‐butadiene), ABS, miscibility of poly(styrene‐co‐acrylonitrile), SAN, with poly(styrene‐co‐n‐phenyl maleimide), SNPMI, having a higher glass transition temperature than SAN was explored. SAN/SNPMI blends casted from solvent were immiscible regardless of copolymer compositions. However, SNPMI copolymer forms homogeneous mixtures with SAN copolymer within specific ranges of copolymer composition upon heating caused by upper critical solution temperature, UCST, type phase behavior. Since immiscibility of solvent casting samples can be driven by solvent effects even though SAN/SNPMI blends are miscible, UCST‐type phase behavior was confirmed by exploring phase reversibility. When copolymer composition of SNPMI was fixed, the phase homogenization temperature of SAN/SNPMI blends was increased as AN content in SAN copolymer increased. To understand the observed phase behavior of SAN/SNPMI blend, interaction energies of blends were calculated from the UCST‐type phase boundaries by using the lattice‐fluid theory combined with a binary interaction model. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1131–1139, 2008     

聚β-羟基丁酸酯/超高分子量聚氧化乙烯共混体系相容性和结晶行为

为了解决废弃塑料引起的“白色污染”问题,世界各国竞相研制开发可生物降解高分子材料,其中,有关聚β 羟基丁酸酯［ｐｏｌｙ（β ｈｙｄｒｏｘｙｂｕｔｙｒａｔｅ）（ＰＨＢ）］的研究尤其活跃．然而,由于商品价格较高,材料本身抗冲击性能较差、加工窗口较窄等限制...     

聚β—羟基丁酯酯／超高分子量聚氧化乙烯共混体系相容性和结晶行为

为了解决废弃塑料引起的“白色污染”问题,世界各国竞相研制开发可生物降解高分子材料,其中,有关聚β羟基丁酸酯［ｐｏｌｙ（βｈｙｄｒｏｘｙｂｕｔｙｒａｔｅ）（ＰＨＢ）］的研究尤其活跃．然而,由于商品价格较高,材料本身抗冲击性能较差、加工窗口较窄等限制...