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1.
Biopolymers are gaining increasing interest because of decline of mineral oil reserves, increasing waste problem, and increasing consciousness of society for environmental problems. However, competitiveness of biopolymers compared with conventional plastics is still limited due to partly insufficient properties and high prices. This study investigates the influence of blending of poly(hydroxybutyrate‐co‐hydroxyvalerate) (PHBV) with poly(butylene adipate‐co‐terephthalate) (PBAT) as well as the influence of addition of functionalized montmorillonite (OMMT) to the blends on morphology and thermal behavior. Dispersion state and morphology of the nanocomposites are studied by X‐ray diffraction as well as scanning electron microscopy. Thermal stability is studied by thermogravimetric analysis and crystallization behavior is studied by differential scanning calorimetry and polarized optical microscopy. With respect to the morphology for the blends it can be seen that the immiscible biopolymers PHBV and PBAT are distributed in interlocking zones. There is a good dispersion and homogeneous distribution of OMMT within the biopolymer blends. The addition of 50% or more PBAT to PHBV as well as the insertion of OMMT enhances thermal stability of PHBV. In the blends, the addition of PBAT retards crystallization of PHBV. The OMMT acts as nucleating agent leading in total to more but less perfect crystals in the blends, and the crystallization slows further due to constraint in the movement of polymer chains. These results contribute to the understanding of the structure–properties relationship of bionanocomposite materials for packaging applications. POLYM. COMPOS., 36:2051–2058, 2015. © 2014 Society of Plastics Engineer  相似文献   

2.
Processability enhancement feasibility of an in-house synthesized poly(lactic acid-co-ethylene terephthalate), PLET, is investigated by blending with commercial poly(ethylene-co-vinyl acetate), EVA, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHBV, and poly(butylene succinate), PBS. The three blend systems are prepared by varying PLET contents, and their properties are characterized. DSC, SEM, and FTIR results indicate that PLET/EVA blends are immiscible, while the corresponding PLET/PBS and PLET/PHBV blends are miscible and partially miscible, respectively. DMA results show that the three blend systems have storage modulus comparable to those of commercial EVA, PHBV, and PBS, when PLET content is kept lower than 50, 25, and 25 wt%, respectively. PLET/EVA blends show higher thermal stability, compared to those of the other two blend systems. Results on degradability tests indicate that PLET/PBS blends show highest hydrolytic degradability, compared to the other two blends, as both blend constituents are associated in the hydrolytic degradation.  相似文献   

3.
Biodegradable blown films comprising of poly(lactide) (PLA) and poly(butylene adipate‐co‐terephthalate) (PBAT) were produced using epoxy functionalized‐poly(lactide) (EF‐PLA) reactive modifiers for rheological enhancement and compatibilization. The epoxy groups on the EF‐PLA modifiers react with PBAT forming an in situ copolymer that localizes at the blend interphase resulting in compatibilization of the polymer blend components. The EF‐PLA modified polymer blends have improved melt strength and the resultant films showed better processability as seen by increased bubbled stability. This allowed for blown films with higher PLA content (70%) compared to the unmodified control films (40%). The static charge build‐up typically experienced with PLA film blowing was decreased with the inclusion of EF‐PLA yielding films with better slip and softness. The compatibilization effect of the EF‐PLA modifiers resulted in significant improvement in mechanical properties. For example, dart test performance was up to four times higher than the control, especially at higher PLA concentrations. Therefore, the rheological enhancement and compatibilization effects of the EF‐PLA reactive modifiers make them ideally suited to create high PLA content films. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43310.  相似文献   

4.
The mechanical properties and morphological changes of poly(lactic acid) (PLA), polycarbonate (PC), and poly(butylene adipate‐co‐terephthalate) (PBAT) polymer blends were investigated. Several types of blend samples were prepared by reactive processing (RP) with a twin‐screw extruder using dicumyl peroxide (DCP) as a radical initiator. Dynamic mechanical analyses (DMA) of binary polymer blends of PC/PBAT indicated that each component was miscible over a wide range of PC/PBAT mixing ratios. DMA of PLA/PBAT/PC ternary blends revealed that PBAT is miscible with PC even in the case of ternary blend system and the miscibility of PLA and PBAT can also be modified through RP. As a result, the tensile strain and impact strength of the ternary blends was increased considerably through RP, especially for PLA/PBAT/PC = 42/18/40 (wt/wt/wt) with DCP (0.3 phr). Scanning electron microscopy (SEM) analysis of the PLA/PBAT/PC blends revealed many small spherical island phases with a domain size of approximately 0.05–1 μm for RP, whereas it was approximately 10 μm without RP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

5.
The morphology and thermal stability of melt‐mixed poly(lactic acid) (PLA)/poly(hydroxybutyrate‐co‐valerate) (PHBV) blends and nanocomposites with small amounts of TiO2 nanoparticles were investigated. PLA/PHBV at 50/50 w/w formed a co‐continuous structure, and most of the TiO2 nanoparticles were well dispersed in the PLA phase and on the interface between PLA and PHBV, with a small number of large agglomerates in the PHBV phase. Thermogravimetric analysis (TGA) and TGA–Fourier‐transform infrared spectroscopy was used to study the thermal stability and degradation behavior of the two polymers, their blends, and nanocomposites. The thermal stability of PHBV was improved through blending with PLA, whereas that of the PLA was reduced through blending with PHBV, and the presence of TiO2 nanoparticles seemingly improved the thermal stability of both polymers in the blend. However, the degradation kinetics results revealed that the nanoparticles could catalyze the degradation process and/or retard the volatilization of the degradation products, depending on their localization and their interaction with the polymer in question. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42138.  相似文献   

6.
Biodegradable polymer blends of poly(butylene succinate) (PBS) and poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) were prepared with different compositions. The mechanical properties of the blends were studied through tensile testing and dynamic mechanical thermal analysis. The dependence of the elastic modulus and strength data on the blend composition was modeled on the basis of the equivalent box model. The fitting parameters indicated complete immiscibility between PBS and PHBV and a moderate adhesion level between them. The immiscibility of the parent phases was also evidenced by scanning electron observation of the prepared blends. The thermal properties of the blends were studied through differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The DSC results showed an enhancement of the crystallization behavior of PBS after it was blended with PHBV, whereas the thermal stability of PBS was reduced in the blends, as shown by the TGA thermograms. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42815.  相似文献   

7.
The anaerobic biodegradation of polymers by soil microorganisms was investigated in shaking flask cultures at different rotation speeds or energy dissipation rates. The polymers included poly(hydroxybutyrate‐co‐hydroxyvalerate) (PHBV), poly(?‐caprolactone) (PCL), polystyrene (PS), two binary PHBV/PCL blends (80/20 and 25/75 w/w), and a triple PHBV/PCL/PS blend (76/5/19 w/w/w). The specific degradation rate of PHBV found from the specimen's residual mass fraction with time was constant after a lag phase and was significantly affected by the agitation strength (<0.5 day?1 at 60 rpm or lower and >15 day?1 at 120 rpm or greater). Tiny polymer fragments were formed on the specimen surface and observed with scanning electron microscopy during degradation. The detachment of those fragments under high hydraulic shear stress caused surface erosion and renewal, resulting in the high degradation rate. The hydraulic shear stress (0.6 Pa) at an energy dissipation rate of 0.5 W/kg was a threshold level, above which the external force did not increase the degradation rate very much. PHBV degradation in the binary blends with compatible PCL was retarded, depending on the blend composition. Blending PHBV with noncompatible PS did not affect PHBV degradation, and the overall degradation rate of the triple blend was faster than the rate of PHBV alone because of the surface erosion of both PHBV and nondegradable PS fragments from the specimens. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1036–1045, 2002  相似文献   

8.
To explore a potential method for improving the toughness of a polylactide (PLA), we used a thermoplastic polyurethane (TPU) elastomer with a high strength and toughness and biocompatibility to prepare PLA/TPU blends suitable for a wide range of applications of PLA as general‐purpose plastics. The structure and properties of the PLA/TPU blends were studied in terms of the mechanical and morphological properties. The results indicate that an obvious yield and neck formation was observed for the PLA/TPU blends; this indicated the transition of PLA from brittle fracture to ductile fracture. The elongation at break and notched impact strength for the PLA/20 wt %TPU blend reached 350% and 25 KJ/m2, respectively, without an obvious drop in the tensile strength. The blends were partially miscible systems because of the hydrogen bonding between the molecules of PLA and TPU. Spherical particles of TPU dispersed homogeneously in the PLA matrix, and the fracture surface presented much roughness. With increasing TPU content, the blends exhibited increasing tough failure. The J‐integral value of the PLA/TPU blend was much higher than that of the neat PLA; this indicated that the toughened blends had increasing crack initiation resistance and crack propagation resistance. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

9.
An important strategy used in the polymer industry in recent years is blending two bio‐based polymers to attain desirable properties similar to traditional thermoplastics, thus increasing the application potential for bio‐based and bio‐degradable polymers. Miscibility of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) with poly(L ‐lactic acid) (PLA) were characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Three different grades of commercially available PLAs and one type of PHBV were blended in different ratios of 50/50, 60/40, 70/30, and 80/20 (PHBV/PLA) using a micro‐compounder at 175°C. The DSC and TGA analysis showed the blends were immiscible due to different stereo configuration of PLA polymer and two distinct melting temperatures. However, some compatibility between PHBV and PLA polymers was observed due to decreases in PLA's glass transition temperatures. Additionally, the blends do not show clear separation by SEM analysis, as observed in the thermal analysis. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

10.
Electrospinning is a method for the preparation of nanosized polymer fibers. Here, electrospinning is used to prepare a blend of a polyester, poly(hydroxybutyrate‐co‐hydroxyvalerate) (PHBV), and a globular protein, bovine serum albumin (BSA). The electrospun blend film is compared with a solution‐cast blend film and with single‐component electrospun films made of PHBV and BSA. In the electrospun blend films, BSA manifests itself as flat ribbons and a fine network formed from fibers less than 50 nm in diameter. The dissolution rate of BSA from the electrospun blended film is lower than from the solution‐cast one. The films are characterized using scanning electron microscopy, differential scanning calorimetry, and contact‐angle measurements. The obtained PHBV+BSA blend films have several emergent properties: a slow BSA dissolution rate, a fine BSA network, and unusual thermal behavior. Thus, the PHBV+BSA blend films introduce a new class of polymer–protein blends. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45090.  相似文献   

11.
In this study, it will be shown that morphologically tailored tricontinuous ternary blends, comprising polybutylene succinate (PBS), polylactic acid (PLA), and poly (butylene adipate‐co‐terephthalate)(PBAT), can generate new materials with excellent properties. Detailed morphological analysis is used to establish that all three phases in the ternary 33%PBS/33%PLA/33%PBAT blend morphology are highly continuous with a phase structure dominated by complete wetting dynamics. PBS is shown to situate itself between PLA and PBAT. This melt processed, self‐assembled, multiple percolated, blend possesses a high elongation at break (567%), high Young's modulus (1130 MPa), high impact strength (271 J/m), and a storage modulus about 50% higher than pure PBS at room temperature. None of the neat materials demonstrate this combination of high properties and the synergy derives from the tricontinuous structure of the system. The ternary nature of the blend allows for a modulation of the crystallinity behavior as examined by differential scanning calorimeter and X‐ray Diffraction. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3005–3012, 2014  相似文献   

12.
Polymer blends can improve material processability and can be used to extrude partially degraded materials, such as expired poly (butylene adipate-co-terephthalate) (PBAT), which cannot be normally extruded. Therefore, in this study, the extrudability of PBAT that has passed its expiration date was restored by blending it with poly (butylene succinate) (PBS). Various polymer blends were extruded and characterized to achieve high-efficiency extrusion. The carbonyl indices in partially degraded PBAT and the corresponding control sample detailed the effects of 98 months of aging on molecular properties. The semicrystalline structure consisted of a mixed ordered arrangement of PBS and PBAT chains dispersed in an amorphous matrix. The microscopic images of the surfaces of the polymer films revealed defects and roughness, followed by an increase in the PBAT concentration in blends. Changes in mechanical properties and water vapor permeability correlated with the PBAT concentration in the blends. To avoid polymer loss, we reported a simple method for using PBAT that has passed its expiration date and cannot be extruded. The results revealed that the polymer films could be used in the packaging industry, especially in food and agricultural sectors.  相似文献   

13.
Phase identification and the study of the interphase region in multi-component polymer blends with a chemically similar structure using conventional techniques is a challenge. In this work, the detailed morphological analysis of such systems is examined. A ternary blend comprised of poly butylene succinate (PBS); poly lactic acid (PLA); and polycaprolactone (PCL) with a partial wetting morphology is carefully selected since all three components are polyesters with low interfacial tensions. It will be shown that a novel technique by applying multivariate analysis (MVA) on time-of-flight secondary ion mass spectrometry (ToF-SIMS) data can effectively identify the complex phase structure, especially in blends with chemically similar components. Furthermore, for the first time for such systems, this technique provides detailed information about interfacial thicknesses and transitions. By employing the principal component analysis (PCA) method on the ToF-SIMS data of pure polymers, specific peaks with a certain molecular ion mass related to each polymer are determined. Using overlaid mappings on the surface of the blend by ToF-SIMS and selected ion masses to identify each polymer results in the differentiation of the various phases represented as a morphological image. In a second step, the multivariate curve resolution (MCR) method is used as a “self modeling curve resolution” for the recovery of pure components from a multi-component mixture when little or no prior information is available. Total pseudo-color RGB images of PBS/PLA/PCL show that PLA droplets unambiguously partially wet the PBS and PCL phases. Since each pixel from the analysis in the high lateral resolution image represents a 200 nm diameter, the interfacial transitions can also be studied for both PLA/PBS and PLA/PCL interfaces. The results show the concentration variation of phases across the interfaces. A complete trace line across the two interfaces (PLA/PBS and PLA/PCL) allows for the quantitative determination of interfacial thickness for the first time for such systems.  相似文献   

14.
A novel thermoplastic vulcanizate (TPV) based on the blends of ethylene vinyl acetate/thermoplastic polyurethane (EVA/TPU) at various blend ratios has been developed via dynamic vulcanization at 180 °C using di‐(2‐tert‐butyl peroxy isopropyl) benzene (DTBPIB) peroxide as the cross‐linking agent. Modification of the EVA/TPU blends via dynamic crosslinking significantly improves the tensile strength and modulus of the system and the improvement is more significant for EVA/TPU 50/50 and 60/40 blends. AFM study shows that crosslinked EVA particles are dispersed in the continuous TPU matrix and the dispersed EVA domain sizes are relatively smaller in EVA/TPU 50/50 and 60/40 blends leading to good mechanical properties. FTIR spectroscopy has been used to characterize the specific chemical changes occurring due to dynamic vulcanization. This TPV has excellent retention of physico‐mechanical properties even after reprocessing twice and the blends also have very good thermal resistance as indicated by aging study. The samples were found to exhibit remarkable improvement in oil resistance property as compared to their uncrosslinked counterpart. The creep behavior of the blends significantly improves after dynamic crosslinking and blends with higher TPU content show better creep resistance. Volume resistivity of all the peroxide vulcanized blends is in the range of 1013 ohm cm, which is suitable for cable sheathing application. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43706.  相似文献   

15.
Polylactide (PLA) blend films with poly(butylenes adipate-co-terephthalate) (PBAT) and a nucleating agent were prepared by the melt compounding technique. Thermal stability of the PLA decreased with added nucleating agent; in contrast, the decomposition temperature increased with the presence of PBAT. In addition, the differential scanning calorimetry thermograms demonstrated that the heterogeneous nucleation and cold crystallisation processes of the PLA blend films were accelerated.

The influence of the type and level of the nucleating agent and the presence of PBAT on the tensile properties, impact resistance, thermal stability and non-isothermal crystallisation behaviours of the PLA blend films were investigated. Both the PLA/nucleating agents and the PLA/PBAT/nucleating agent blends showed significant effects from the changes in the nucleation process on their tensile properties, impact toughness and thermal behaviour. Furthermore, the impact energy that the PLA blends absorbed during the entire impact tension test was obviously enhanced by the increased content of the nucleating agent.  相似文献   


16.
PHBV/PBAT混物形态与性能研究   总被引:1,自引:0,他引:1  
通过熔融共混的方法制备了完全生物降解的羟基丁酸-羟基戊酸共聚物/丁二醇-己二酸-对苯二甲酸共聚物共混材料(PHBV/PBAT),研究了 PHBV/PBAT 共混物的相形态、力学性能和热性能。结果表明,PBAT 为50%(质量含量,下同)时,共混物断裂伸长率为55%,缺口冲击强度为542 J/m,分别为改性前 PHBV 的19倍和22.6倍,显著提高了 PHBV 的韧性。SEM 照片显示,30%的 PBAT 以分散相存在 PHBV 基体中;当 PBAT 超过50%后,PBAT 可能形成连续相,在受到外力过程中发生大形变从而吸收较多的能量。DSC 研究表明,PBAT 的加入抑制了PHBV 的结晶过程,使 PHBV 结晶温度降低20~40℃。  相似文献   

17.
Carbon nanotubes (CNTs) and barium titanate (BaTiO3) (BT) were simultaneously introduced into the immiscible blend poly(ethylene‐co‐vinyl acetate)/thermoplastic urethane (EVA/TPU), and the EVA/TPU/CNT/BT quaternary polymer composite blends with core–shell structured island TPU domain were successfully prepared, in which CNTs in the TPU domain act as the core and the BT spheres at the interface of the TPU and EVA act as the shell. A core–shell structured island can lead to the formation of micro‐capacitors and further accumulate electron storage owing to the incorporation of CNTs and BT; on the other hand, a BT shell can be assembled along the TPU spheres, reducing the possibility of formation of a conductive CNT network, resulting in suppressed dielectric loss. Therefore, CNTs and BT were tailor‐made into blend composites with a core–shell structured domain, which can achieve an increased dielectric constant by 176% and decreased low dielectric loss by 80% compared with the blend composites with only CNTs in the TPU domain. © 2019 Society of Chemical Industry  相似文献   

18.
This work reports the enhancement of the processing window and of the mechanical and thermal properties of biopolymer blends of polyamide 1010 (PA1010) and bio‐based high‐density polyethylene (bio‐HDPE) at 70/30 (w/w) achieved by means of natural additives. The overall performance of the binary blend melt‐mixed without additives was poor due to both the relatively low thermal stability of bio‐HDPE at the processing temperatures of PA1010, that is, 210–240 °C, and the lack of or poor miscibility between the two biopolymers. Gallic acid, a natural phenolic compound, was added at 0.8 parts per hundred resin (phr) of biopolymer blend to enhance the thermal stability of the green polyolefin and therefore enlarge the processing window of the binary blend. Maleinized linseed oil, a multi‐functionalized vegetable oil, was then incorporated at 5 phr to compatibilize the biopolymers and the performance of the blend was also compared with that of a conventional petroleum‐derived copolymer, namely poly[ethylene‐co‐(acrylic acid)]. The resultant biopolymer blends showed a marked enhancement in thermal stability and also improved toughness when both natural additives were combined. This work can potentially serve as a sound base study for the mechanical recycling of similar blends containing bio‐based but non‐biodegradable polymers. © 2019 Society of Chemical Industry  相似文献   

19.
Poly(butylene succinate) (PBS) and polylactide (PLA) were blended in a co‐rotating twin‐screw extruder with various contents of PBS from 0 to 100 wt%. The effect of PBS content on the thermal and mechanical properties of PBS/PLA blends was investigated by using DSC, softening point measurements, a Charpy impact test and tensile testing. The Fourier transform infrared spectra showed that the polymers are immiscible, but the addition of PBS could modify the PLA structure in PBS/PLA blends by changing the content of amorphous and crystalline phases. In addition, the cold crystallization temperature of PLA in blends decreases in comparison with pure PLA, which shows that PBS could have a plasticizing effect on PLA. This is confirmed by the results of DSC analysis. The mechanical properties of the blends depend on the percentage of PBS addition. Typically, the mechanical properties of PBS/PLA blends are intermediate between the properties of the polyesters from which they are obtained. However, in some cases unexpected changes in mechanical properties of the blends were observed. For example, the elongation at break for a PBS/PLA blend containing 10 wt% PLA is higher than for pure PBS. © 2019 Society of Chemical Industry  相似文献   

20.
Viscoelastic, interfacial properties, and morphological data were employed to predict the thermal and mechanical properties of compatibilized poly(lactic acid) (PLA)/thermoplastic polyurethane (TPU) blends. The combination of interfacial thickness measured by contact angle and entanglement density determined by dynamical mechanical analysis analyze data was employed to evaluate the mechanical behavior of PLA/TPU blends with and without ethylene-butyl acrylate-glycidyl methacrylate (EBG) compatibilization agent. The PLA/TPU blend (70/30 wt %) was prepared in a Haake internal mixer at 190 °C and compatibilized with different contents of EBG. The evaluation of the interfacial properties revealed an increase in the interfacial layer thickness of the PLA/TPU blend with EBG. The scanning electronic microscopy images showed a drastic reduction in the size of the dispersed phase by increasing the compatibilizer agent EBG content in the blend. The compatibilization of the PLA/TPU blends improved both the Izod impact strength and yield stress by 38 and 33%, respectively, in comparison with neat PLA/TPU blend. The addition of EBG into PLA/TPU blends significantly increased the entanglement density and the PLA toughening but resulted in a decrease of PLA deformation at break. The PLA and TPU glass transitions were affected by the EBG, suggesting that the PLA and TPU domains were partially miscible. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48926.  相似文献   

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