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1.
Four blends of poly(hydroxybutyrate) (PHB) and poly(butylene succinate) (PBSU), both biodegradable semicrystalline polyesters, were prepared with the ratio of PHB/PBSU ranging from 80/20 to 20/80 by co-dissolving the two polyesters in N,N-dimethylformamide and casting the mixture. Differential scanning calorimetry (DSC) and optical microscopy (OM) were used to probe the miscibility of PHB/PBSU blends. Experimental results indicated that PHB showed some limited miscibility with PBSU for PHB/PBSU 20/80 blend as evidenced by the small change in the glass transition temperature and the depression of the equilibrium melting point temperature of the high melting point component PHB. However, PHB showed immiscibility with PBSU for the other three blends as shown by the existence of unchanged composition independent glass transition temperature and the biphasic melt. Nonisothermal crystallization of PHB/PBSU blends was investigated by DSC using various cooling rates from 2.5 to 10 °C/min. During the nonisothermal crystallization, despite the cooling rates used two crystallization peak temperatures were found for PHB/PBSU 40/60 and 60/40 blends, corresponding to the crystallization of PHB and PBSU, respectively, whereas only one crystallization peak temperature was observed for PHB/PBSU 80/20 and 20/80 blends. However, it was found that after the nonisothermal crystallization the crystals of PHB and PBSU actually co-existed in PHB/PBSU 80/20 and 20/80 blends from the two melting endotherms observed in the subsequent DSC melting traces, corresponding to the melting of PHB and PBSU crystals, respectively. The subsequent melting behavior was also studied after the nonisothermal crystallization. In some cases, double melting behavior was found for both PHB and PBSU, which was influenced by the cooling rates used and the blend composition.  相似文献   

2.
Two biodegradable polymers, that is, poly(butylene succinate) (BN) and cellulose acetate (CA), were solvent‐cast blended with chloroform. Homogeneous films were obtained from the blend by the addition of tetraisopropyl titanate (TP) as a compatibilizer. We measured the viscosity of the blend solution to investigate the function of TP during the blending process. From the measurement, we conclude that there are interactions among TP, BN, and CA. From optical observation and thermal measurements of the blend films, we found that the structure of blends is in a pseudostable state and that the addition of TP makes the structure units small. From thermogravimetric analyses, we found that the addition of TP decreases the thermal decomposition temperature of the BN/CA blends. From the measurements of mechanical properties of the blends, we found that changing the blend ratio can produce the materials with a wide range of mechanical properties. The hydrolysis of the blends was investigated. The molecular scission of BN/CA blends takes place uniformly not only from the outside but also from the inside of the films. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1750–1758, 2002  相似文献   

3.
An aliphatic/aromatic polyester blend has been dealt with in this study. As an aliphatic polyester, poly(butylene succinate) (PBS) was used, which is thought to possess biodegradability, but it is relatively expensive. It has been blended with poly(butylene terephthalate) (PBT) in order to obtain a biodegradable blend with better mechanical properties and lower cost. The miscibilities of PBS–PBT blends were examined not only from the changes of Tg but also from log G′–log G" plots. Dynamic mechanical thermal analyzer (DMTA) was an appropriate, sensitive method to obtain the glass transitions properly. Thermal stabilities of PBS and PBT were also verified at the temperature of 240°C. A transesterification reaction between two polyesters at 240°C was hardly detectable so that it did not affect the miscibilities and properties of the blends. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 945–951, 1999  相似文献   

4.
Nano‐scale poly(butylene terephthalate) (PBT) fibers were prepared from PBT/cellulose acetate butyrate (CAB) immiscible polymer blends due to in situ microfibrillar formation during a melt extruding process. The morphological development of the dispersed phase was studied with samples collected at different zones in a twin screw extruder. It was found that the holistic developmental trends of PBT dispersed phase were nearly the same. Fibers began to form even under the shear flow of the twin‐screw extruder. The morphology developmental mechanism of the dispersed phase involved the formation of sheets, holes and network structures, then the size reduction and formation of nanofibers. The effect of viscosity ratio, blend ratio, and shear rate on the morphology evolution was also studied by analyzing the shape and size distribution of the samples. The diameter distribution of the nanofibers could be affected by viscosity ratio, blend ratio, and shear rate. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers  相似文献   

5.
A series of poly(butylene succinate) ionomers (PBSi) containing 5-sodium sulfoisophthalate units were prepared by bulk polymerization of succinic acid and 1,4-butanediol in the presence of dimethyl 5-sulfoisophthalate sodium salt (DMSI) up to 5 mol% of diacid monomer. Conspicuous variation of the storage modulus for PBSi was observed, depending on the content of DMSI. The increasing rate of cluster Tg was lower compared to those of amorphous polymer-based ionomers. These results were probably due to the lower clustering ability of semi-crystalline PBSi as compared with amorphous-based ionomers. Non-contact atomic force microscopy confirmed that the size of PBSi-3 clusters was about 40∼50 nm, demonstrating that the clusters were aggregated. Melt rheological analysis was carried out to investigate the effects of ionic groups on the rheological properties as a function of temperature or shear force in the molten state. The melt viscosities of PBSi showed higher values than the parent PBS up to about 190 °C, while with further increasing temperature a falling inflection region of melt viscosity was observed. It was suggested that the relaxation of PBSi chains was due to the thermal dissociation of ionic aggregates.  相似文献   

6.
The kinetics of the isothermal crystallization process from the melt of pure poly(butylene succinate)‐co‐(butylene carbonate) (PBS‐co‐BC) and its blends with cellulose acetate butylate (CAB) (10–30 wt%) was studied by differential scanning calorimetry (DSC) and the well‐known Avrami equation. In the blends, the overall crystallization rate of PBS‐co‐BC became slower with increasing CAB content. The equilibrium melting temperature ( ) of PBS‐co‐BC decreased with increasing CAB content, which was similar to that with other miscible crystalline/amorphous polymer blends. The slower crystallization kinetics of PBS‐co‐BC in the blends was explicable in terms of a diluent effect of the CAB component. By application of Turnbull–Fisher kinetic theory for polymer–diluent blend systems, the surface free energy (σe) of pure PBS‐co‐BC and of the blends was obtained, indicating that the blend with CAB resulted in a decrease in the surface free energy of folding of PBS‐co‐BC lamellar crystals. Copyright © 2006 Society of Chemical Industry  相似文献   

7.
To improve the tensile properties and degradability of poly(butylene succinate) (PBS) for biomedical usage, biodegradable polymer blends have been developed. A series of PBS and poly(lactic acid) (PLA) blends were prepared, and their degradation behaviors in simulated body fluid for 16 months were investigated based on morphology, tensile test, weight analysis, and molecular weight. The results showed that the incorporation of PLA into PBS increased the initial tensile strength to some extent, and the blends lost their tensile properties earlier than their parent polymers with the proceeding of hydrolysis. Both blends and parent polymers went through a plateau and subsequent rise stage in mass loss and water absorption, but the blends hydrolyzed faster than the parent polymers. The molecular weight variations also demonstrated faster hydrolysis of the blends. Moreover, both blends and their parent polymers underwent a slow-to-fast transition in their hydrolysis rates. When the M n of PBS and PLA reached 4.0 × 104 and 9.0 × 104, the hydrolysis of parent polymers and blends began to accelerate, which is the start of auto-acceleration. The blends hydrolyzed faster in both stages. The interface between the components initiated accelerating hydrolysis in the first stage, and the reciprocal auto-acceleration effect resulted in faster hydrolysis of the blends in the second stage.  相似文献   

8.
黄勇  刘俊红  肖金富  何凤霞 《化工进展》2018,37(12):4744-4751
以聚丁二酸丁二醇酯(PBS)和聚乙二醇硬脂酸酯(PEOST)为原料,采用溶液共混法制备了PEOST质量分数分别为10%(POS-10)和30%(POS-30)的两种合金材料。通过差示扫描量热法(DSC)研究了合金材料的非等温结晶行为,用莫志深(Mo)法分析了PBS的非等温结晶动力学,采用Kissinger法和Friedman法计算PBS的结晶活化能,并用红外(FTIR)和偏光显微镜(POM)进行表征。研究结果表明:PBS先结晶形成结晶微区不利于PEOST结晶,而较高含量的PEOST有利于PBS的结晶。受PBS先结晶的影响,POS-10降温DSC曲线没有出现PEOST的结晶峰,而POS-30在低的降温速率情况下出现了PEOST双结晶峰;升温DSC曲线中两试样均出现了PEOST的熔融峰。在相同的冷却速率下,POS-30的PEOST熔融温度(Tm)和熔融焓(△Hm)大于POS-10;POS-30的PBS结晶峰温度(Tp)、结晶焓(△Hc)大于POS-10,而结晶半峰宽(D)值更小;但两者的Tm和△Hm相当。随冷却速率的增加,PBS的D值增大,而PEOST的D值却降低;冷却速率的增加对PBS的Tm值影响不大,但使PEOST的Tm略有减小。Mo法适合用于共混物中PBS的非等温结晶动力学分析。POS-30的PBS绝对值结晶活化能要大于POS-10。POS-30在红外光谱谱图中出现了PEOST结晶的红外响应峰(1109cm-1和841cm-1)而POS-10没有。  相似文献   

9.
The reactive blends were prepared by the blending of poly(lactic acid) (PLA) with poly(butylene succinate) (PBS) in the presence of dicumyl peroxide (DCP) as a radical initiator in the melt state. The gel fractions, morphologies, crystallization behaviors, and rheological and mechanical properties of the reactive blends were investigated. Some crosslinked/branched structures were formed according to the rheological measurement and gel fraction results, and the crosslinked/branched structures played the role of nucleation site for the reactive blends. The PLA–PBS copolymers of the reactive blends acted as a compatibilizer for the PLA and PBS phases and, hence, improved the compatibility between the two components. Moreover, it was found that the reactive blends showed the most excellent mechanical properties as the DCP contents were 0.2 and 0.3 phr. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39580.  相似文献   

10.
Poly(butylene succinate)/cellulose diacetate (PBS/CDA) blends were prepared by the solution blending method from poly(butylene succinate) (PBS) and cellulose diacetate (CDA). The influence of hydrogen bond on the structure, morphology, crystallization, as well as the physical properties of PBS/CDA blends was significantly investigated. The fourier transform infrared spectroscopy (FTIR) results indicated that the carbonyl groups of PBS shifted to higher wavenumbers and disappeared at the content of 60% CDA, due to the formation of hydrogen bond between PBS and CDA. The wide‐angle X‐ray diffractometer (WAXD) and differential scanning calorimeter (DSC) analysis suggest that the crystallization of PBS was significantly restricted by the incorporation of CDA, which is also attributed to the hydrogen bonding. The scanning electron miscroscope (SEM) and polarized optical microscopy (POM) results revealed that PBS and CDA were miscible without appearance of obvious phase separation. The hydrogen bonding interaction led to the change of decomposing mechanism of blends as determined by thermogravimetric analysis (TGA), as well as the increase of the elongation at break due to the reduced crystallinity of PBS. The existence of CDA led to the decrease of water contact angle, showing of the improved hydrophilicity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

11.
Miscibility and crystallization behavior have been investigated in blends of poly(butylene succinate) (PBSU) and poly(ethylene oxide) (PEO), both semicrystalline polymers, by differential scanning calorimetry and optical microscopy. Experimental results indicate that PBSU is miscible with PEO as shown by the existence of single composition dependent glass transition temperature over the entire composition range. In addition, the polymer-polymer interaction parameter, obtained from the melting depression of the high-Tm component PBSU using the Flory-Huggins equation, is composition dependent, and its value is always negative. This indicates that PBSU/PEO blends are thermodynamically miscible in the melt. The morphological study of the isothermal crystallization at 95 °C (where only PBSU crystallized) showed the similar crystallization behavior as in amorphous/crystalline blends. Much more attention has been paid to the crystallization and morphology of the low-Tm component PEO, which was studied through both one-step and two-step crystallization. It was found that the crystallization of PEO was affected clearly by the presence of the crystals of PBSU formed through different crystallization processes. The two components crystallized sequentially not simultaneously when the blends were quenched from the melt directly to 50 °C (one-step crystallization), and the PEO spherulites crystallized within the matrix of the crystals of the preexisted PBSU phase. Crystallization at 95 °C followed by quenching to 50 °C (two-step crystallization) also showed the similar crystallization behavior as in one-step crystallization. However, the radial growth rate of the PEO spherulites was reduced significantly in two-step crystallization than in one-step crystallization.  相似文献   

12.
Silica nanoparticles and poly(butylene succinate) (PBS) nanocomposites were prepared by a melt‐blending process. The influence of silica nanoparticles on the nonisothermal crystallization behavior, crystal structure, and mechanical properties of the PBS/silica nanocomposites was investigated. The crystallization peak temperature of the PBS/silica nanocomposites was higher than that of neat PBS at various cooling rates. The half‐time of crystallization decreased with increasing silica loading; this indicated the nucleating role of silica nanoparticles. The nonisothermal crystallization data were analyzed by the Ozawa, Avrami, and Mo methods. The validity of kinetics models on the nonisothermal crystallization process of the PBS/silica nanocomposites is discussed. The approach developed by Mo successfully described the nonisothermal crystallization process of the PBS and its nanocomposites. A study of the nucleation activity revealed that the silica nanoparticles had a good nucleation effect on PBS. The crystallization activation energy calculated by Kissinger's method increased with increasing silica content. The modulus and yield strength were enhanced with the addition of silica nanoparticles into the PBS matrix. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

13.
Thermoplastic starch/poly(butylene succinate) (TPS/PBS), an entirely biodegradable polymer blend, was prepared by a two-step extrusion method. Maleic anhydride grafted PBS (rPBS) was successfully synthesised as an interfacial compatibiliser. The miscibility, morphology, thermal behaviour and mechanical properties of the TPS/PBS blends were investigated. The results demonstrated that the strength and elongation at break of TPS/PBS blends were greatly increased with the addition of rPBS in PBS blends due to improved interfacial miscibility. Better distribution and smaller phase domain were observed in the blends with higher content of compatibilisers. The water resistance was also enhanced by incorporation of rPBS. It was indicated that compatibilised TPS/PBS blends possessed a combination of good biodegradability, improved strength and high water resistance. TPS/PBS blend was expected to serve as a promising packing material.  相似文献   

14.
Poly(trimethylene terephthalate) (PTT)/cellulose acetate butyrate (CAB) blends were prepared by melting blending through a co‐rotating twin screw extruder. The structures of PTT/CAB blends were characterized by scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectra, and the results showed that CAB phase dispersed homogeneously in the PTT matrix and there existed evident phase interface between PTT and CAB. The nonisothermal crystallization behavior was investigated by differential scanning calorimetry (DSC) and was described with modified Avrami equation of Jeziorny and Mo equation, respectively. The results indicated that the half crystallization time (t1/ 2) is much shorter, the nonisothermal crystallization kinetic rate constant (Zc) is bigger at a given cooling rate, the cooling rate [Fz(T)] is smaller at a given relative crystallinity (X t) of PTT/CAB blends than those of PTT, which proved that the addition of CAB improved the crystallization of PTT and made PTT crystallize more perfect and faster than pure PTT. In addition, thermogravimetric analysis (TGA) curves of PTT and PTT/CAB blends showed that effects of CAB content on the thermal decomposition of PTT/CAB blends were little. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers  相似文献   

15.
In this study, crosslinked poly (butylene succinate) (PBS) was prepared successfully by the reactions of the end hydroxyl groups of PBS with the isocyanate groups of hexamethylene diisocyanate prepolymer (HDIP) using a vane extruder (VE) followed by compression moulding. Torque and gel permeation chromatography showed that the PBS was successfully corsslinked by HDIP. The effects of varied HDIP on properties such as mechanical, thermal properties, and capillary rheological behaviours were also evaluated. The results indicated that HDIP crosslinked PBS with high efficiency. The gel fraction of the crosslinked PBS increased to 57% with the 1.5?wt-% HDIP loading. Differential scanning calorimetry revealed that the cross-link points in the crosslinked samples act as crystal nuclei and the crystallisation temperature increase. Dynamic mechanical analysis revealed that the glass transition temperature (Tg) increased with increase in gel fraction. This may be caused by the reduced molecular chain mobility for corsslinked samples. The capillary rheological properties showed that all samples exhibit non-Newtonian and shear thinning characteristics in the range of applied shear rates, and the apparent viscosity increased with the HDIP content. What's more, the crosslinked PBS also showed improved mechanical properties and thermal stability.  相似文献   

16.
Morphologies of PBS/PBA blends varying in blend ratio at different crystallization temperatures of PBS component were studied using optical and atomic force microscopies. It was found that interspherulitic phase segregation of PBA takes place at high temperature, e.g. 100 °C, for all blend compositions due to the high diffusion length. On the contrary, no interspherulitic phase segregation of PBA at 75 °C occurs at all, consistent with a shorter diffusion length. It was further found that the PBA melt acted as a diluter, affecting the morphology of PBS, which in turn influenced the phase separation behavior of PBA remarkably. At 100 °C, with increasing PBA concentration, the resultant open structure of PBS caused by the diluting effect of the PBA melt makes it necessary to retain some portion of the PBA melt between the PBS lamellae. This leads to the concurrence of interlamellar and interspherulitic phase segregations. An even higher PBA content results in the occurrences of all three phase separation options, i.e. interlamellar, interfibrillar and interspherulitic phase segregations. At 75 °C, in blends with PBA as a minority phase, mainly interlamellar segregation of PBA occurs. For a 50/50 blend, interlamellar and interfibrillar phase segregations take place simultaneously. For a PBA in-rich blend, PBS forms only a spherulitic framework, filled in with the PBA lamellar crystals, indicating that interfibrillar mode is the main phase separation process.  相似文献   

17.
The vital differences between the use of untreated starch and gelatinized starch in blends with poly(butylene succinate) (Bionolle) were thoroughly examined in this study. The melting temperature decreased slightly with increasing dosages of untreated and gelatinized starch. The added starch perhaps tended to disrupt the intermolecular hydrogen bonding within the Bionolle matrix. On the other hand, a large increase in the crystallinity was seen with the addition of starch. Starch appeared to play a nucleating role in the blends. The trend of the glass‐transition temperature decreasing with the starch level was similar to the trend of the melting temperature. For the same starch content, the glass‐transition temperature showed some variations. For blends containing a certain amount of gelatinized starch, the thermal stability remained to a certain degree but continued to decrease. This was ascribed to the relatively low heat stability of starch. As for the mechanical properties, a significant increase in the tensile strength (up to 2 times) was observed when untreated starch was replaced with gelatinized starch in the blends. Similarly, the tear strength increased up to 1.5 times if gelatinized starch was employed. Apparently, the gelatinization of starch was efficiently achieved for promoting its compatibility with Bionolle. In all cases, the mechanical properties of Bionolle blended with gelatinized starch were better than those of Bionolle blended with untreated starch. A morphological investigation provided evidence in support of these findings. This relatively low‐cost gelatinization approach provides an alternative to a high‐cost compatibilizer approach for improving the performance of biodegradable blends. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 257–264, 2005  相似文献   

18.
Jiaoming Lu  Wantai Yang 《Polymer》2007,48(14):4196-4204
Both poly(l-lactide) (PLLA) and poly(ethylene succinate) (PES) are biodegradable semicrystalline polyesters. The disadvantages of poor mechanical properties and slow crystallization rate of PLLA limit its wide application. Fully biodegradable polymer blends were prepared by blending PLLA with PES. Miscibility, crystallization behavior, and mechanical properties of PLLA/PES blends were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), wide angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), and tensile tests in this work. Experimental results indicated that PLLA was immiscible with PES. Crystallization of PLLA/PES blends was studied by DSC using two-step crystallization condition and analyzed by the Avrami equation. The crystallization rate of PLLA at 100 °C was accelerated with the increase of PES in the blends while the crystallization mechanism did not change. In the case of the isothermal crystallization of PES at 67.5 °C, the crystallization mechanism did not change, and the crystallization rate decreased with the increase of PLLA. The mechanical properties of PLLA/PES blends were examined by tensile testing. The elongation at break of PLLA was improved significantly in the blends, while its considerably high Young's modulus was still kept. SEM images of fracture surfaces indicated that the fracture behavior of PLLA/PES blends changed from brittle fracture to ductile fracture behavior in the blends.  相似文献   

19.
Mitsuhiro Shibata  Yusuke Inoue 《Polymer》2006,47(10):3557-3564
The blends of poly(l-lactide) (PLLA) with poly(butylene succinate) (PBS) and poly(butylene succinate-co-l-lactate) (PBSL) containing the lactate unit of ca. 3 mol% were prepared by melt-mixing and subsequent injection molding, and their mechanical properties, morphology, and crystallization behavior have been compared. Dynamic viscoelasticity and SEM measurements of the blends revealed that the extent of the compatibility of PBSL and PBS with PLLA is almost the same, and that the PBSL and PBS components in the blends with a low content of PBSL or PBS (5-20 wt%) are homogenously dispersed as 0.1−0.4 μm particles. The tensile strength and modulus of the blends approximately followed the rule of mixtures over the whole composition range except that those of PLLA/PBS 99/1 blend were exceptionally higher than those of pure PLLA. All the blends showed considerably higher elongation at break than pure PLLA, PBSL, and PBS. Differential scanning calorimetric analysis of the blends revealed that the isothermal and non-isothermal crystallization of the PLLA component is promoted by the addition of a small amount of PBSL, while the addition of PBS was much less effective.  相似文献   

20.
Poly(ethylene succinate) (PES), poly(butylene succinate) (PBS), and PES‐rich copolyesters were synthesized using an effective catalyst, titanium tetraisopropoxide. PES was blended with minor amounts of PBS for the comparison. The compositions of the copolyesters and the blends were determined from NMR spectra. Their thermal properties were studied using a differential scanning calorimeter (DSC), a temperature modulated DSC (TMDSC), and a thermogravimetric analyzer. No significant difference exists among the thermal stabilities of these polyesters and blends. For the blends, the reversible curves of TMDSC showed a distinct glass‐rubber transition temperature (Tg), however, the variation of the Tg values with the blend compositions was small. Isothermal crystallization kinetics and the melting behavior after crystallization were examined using DSC. Wide‐angle X‐ray diffractograms (WAXD) were obtained for the isothermally crystallized specimens. The results of DSC and WAXD indicate that the blends have a higher degree of crystallinity and a higher melting temperature than those of the corresponding copolymers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

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