Compatibilization of Poly(ethylene terephthalate)/Polypropylene Blends with Maleic Anhydride Grafted Polyethylene-Octene Elastomer

Blends of poly(ethylene terephthalate) (PET) and polypropylene (PP) at composition 80/20 with and without a compatibilizing agent were studied. Both materials are widely used in the soft drink bottle industry. The compatibilizing agent was a maleic anhydride grafted polyethylene-octene elastomer (POE-g-MA). The olefinic segment of POE is compatible with PP, whereas the maleic anhydride is affined with PET carbonyl groups. The effectiveness of the compatibilizing agent was evaluated using different techniques, such as Fourier transform IR spectroscopy, mechanical analysis, scanning electron microscopy, dynamic mechanical analysis, and rheological analysis. The results show that the addition of POE-g-MA promotes a fine dispersed-phase morphology, and improves process ability and toughness of these blends. Shifts in the glass-transition temperature of the PET phase and the increase in the melt viscosity of the compatibilized blends indicated enhanced interactions between the discrete PET and PP phases induced by the functional compatibilizer.     

Thermal,Mechanical and Rheological Properties of Polypropylene/Poly(ethylene-co-methyl acrylate) Blends

Isotactic polypropylene (PP) has been blended with poly(ethylene-co-methyl acrylate) (EMA) (75/25 wt/wt%) in a single-screw extruder. The compatibilizing effect of polypropylene grafted with maleic anhydride (PP-g-MAH) has been examined. The nonisothermal crystallization of the developed blends has been investigated using differential scanning calorimetry (DSC) and analyzed using Avrami, Tobin and Liu models. The thermal stability of the blends was assessed through thermogravimetric analysis (TGA). The tensile and impact properties, as well as the melt viscosity, have also been determined. The presence of rubber accelerates the crystallization of PP. The thermal stabilities of the blends are intermediate between those of their constituents. Tensile strength and modulus are reduced upon incorporation of EMA into PP, but ultimate elongation and impact strength are improved. The melt viscosity variation with shear rate for all the systems was typical of shear-thinning behavior. The compatibilizing agent has a pronounced effect on enhancing the thermal and mechanical properties of the blend.     

聚(丁二酸乙二酯-共-对苯二甲酸乙二酯)的流变性能

以对苯二甲酸、丁二酸和乙二醇为单体合成了3组不同特性黏度的聚(丁二酸乙二酯-共-对苯二甲酸乙二酯) (PEST),采用毛细管流变仪重点研究了样品的流变性能.结果表明:共聚酯PEST是假塑性流体,呈现典型的切力变稀现象;随着剪切速率增大,黏流活化能降低;非牛顿指数随着特性黏度的增大而减小,随温度的升高而增大;结构黏度指数随着温度升高而降低,随特性黏度的增大而逐渐增加.流变性能的研究结果对PEST共聚酯的加工生产提供了一定参考.     

Blends of poly(ethylene terephthalate) and poly(butylene terephthalate)

Commercial grade poly(ethylene terephthalate), (PET, intrinsic viscosity = 0.80 dL/g) and poly(butylene terephthalate), (PBT, intrinsic viscosity = 1.00 dL/g) were melt blended over the entire composition range using a counterrotating twin‐screw extruder. The mechanical, thermal, electrical, and rheological properties of the blends were studied. All of the blends showed higher impact properties than that of PET or PBT. The 50:50 blend composition exhibited the highest impact value. Other mechanical properties also showed similar trends for blends of this composition. The addition of PBT increased the processability of PET. Differential scanning calorimetry data showed the presence of both phases. For all blends, only a single glass‐transition temperature was observed. The melting characteristics of one phase were influenced by the presence of the other. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 75–82, 2005     

Recyclability of In Situ Microfibrillar Poly(ethylene terephthalate)/High‐Density Polyethylene Blends

Repetitive processing was employed to assess the recyclability of in situ microfibrillar poly(ethylene terephthalate) (PET)/high‐density polyethylene (HDPE) blends which were fabricated through a “rectangular slit die extrusion–hot stretching–quenching” process. For comparison, the conventional PET/HDPE blends were also obtained using the same processing operation but without hot stretching. The morphological observation indicated that slit die extrusion and hot stretching successfully made the dispersed PET phase deform in situ into well‐defined microfibrils. The average diameter of the microfibrils increased with the processing cycles. The rheological properties obtained from the parallel‐plate dynamic rheometer suggested that the microfibrillar blends have higher viscosity and viscoelastic moduli (storage and loss moduli) as well as better flow stability than the conventional PET/HDPE blend. More importantly, with the increase in the processing cycles, an increase in yield strength and unchanged tensile modulus were observed for in situ microfibrillar blends, while a decrease in these properties for conventional blend, indicating that the in situ microfibrillar PET/HDPE blends have promising recycling potential.

     

Miscibility,Mechanical and Thermal Properties of Melt-Mixed Poly(trimethylene terephthalate)/Polypropylene Blends

This study examined the miscibility, mechanical and thermal properties of melt-mixed blends of PTT(poly(trimethylene terephthalate)) with PP(isotatic polypropylene). DMA and SEM results indicated that the PTT/PP blends are immiscible. Revealed from TGA analyses, the blends with a higher PP content showed a higher degradation temperature. A complex melting behavior was observed for the blends. The isothermal crystallization kinetics of the blends was analyzed from 200°C to 210°C using the Avrami equation. The WAXD results showed that the crystal structure of PTT remained unchanged in the blends. Nevertheless, the PP rich blends possessed lower tensile strength and higher elongation at break.     

Preparation of Poly(ethylene terephthalate)/Poly(amino ether) Blends by means of the Addition of Poly(butylene terephthalate)

Summary: Blends based on poly(ethylene terephthalate), PET, with poly(amino ether) (PAE) contents up to 40% were obtained by the addition of 20% poly(butylene terephthalate) (PBT) to the PET matrix. PBT mixed with PET led to a decrease in the T_m of the matrix that was enough to produce homogeneous blends by mixing in the melt state. Despite the presence of a single peak observed by dynamic‐mechanical analysis, the blends were biphasic, with amorphous phases in which minor amounts of the other component, both reacted and mixed, were present. This presence of minor components gave a fine morphology and significant adhesion that, together with the higher orientation of PAE in the blends, produced blends with a clear synergism in the modulus of elasticity, notched impact strength similar to that of the neat components, and high ductility up to 30% PAE.

Young's modulus of the PET‐PBT/PAE blends.     

PP/PB共混材料的力学及流变性能研究

采用哈克双螺杆挤出机制备了聚丙烯/聚丁烯-1(PP/PB)共混材料,考察了PB的熔体流动速率(MFR)和用量对PP流变性能和力学性能的影响。结果表明:PP与PB二者相容性良好,当PB质量分数为30%时,PP/PB200(MFR为200 g/10 min)共混材料的MFR最大为37.90 g/10 min,约是纯PP的4.15倍,PP/PB0.5(MFR为0.5 g/10 min)共混材料的MFR最小为7.59 g/10 min,与纯PB相比降低了16.87%;随着PB MFR的增加,PP/PB共混材料的熔体强度降低;当PB MFR为0.5 g/10 min时,对PP有明显的增强和增韧效果,PP/PB共混材料的拉伸强度为31.11 MPa,冲击强度为48.52 kJ/m²,与纯PP相比分别提高了28.82%和185.24%。     

Poly(ethylene terephthalate)/polypropylene reactive blends through isocyanate functional group

To evaluate the compatibilization effects of an isocyanate group on poly(ethylene terephthalate)/polypropylene (PET/PP) blends through a reactive blend, PP grafted with 2‐hydroxyethyl methacrylate‐isophorone diisocyanate (PP‐g‐HI) was prepared and blended with PET. In view of the blend morphology, the presence of PP‐g‐HI reduced the particle size of the dispersed phase by the reduced interfacial tension between the PP and PET phases, indicating the in situ copolymer (PP‐g‐PET) generated during the melt blending. The DSC thermograms for the cooling run indicated that the PET crystallization in the PP‐g‐HI rich phase was affected by the chemical reactions of PET and PP‐g‐HI. The improved mechanical properties for the PET/PP‐g‐HI blends were shown in the measurement of the tensile and flexural properties. In addition, the water absorption test indicated that the PET/PP‐g‐HI blend was more effective than the PET/PP blend in improving the water resistance of PET. The positive properties of PET/PP‐g‐HI blends stemmed from the improved compatibilization of the PET/PP blend. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1056–1062, 2001     

Morphology and electrical properties of carbon black/poly(ethylene terephthalate)/polypropylene composite

This work attempts to develop a carbon black (CB) filled conductive polymer composite based on poly(ethylene terephthalate) (PET) and polypropylene (PP). The process follows by localizing the CB particles in the minor phase (PET), and then the conductive masterbatch was elongated to form conductive microfibrils in PP matrix during melt extrusion process. After compression molding, a fine conductive three‐dimensional microfibrillar network is constructed. For comparison purpose, CB, PET, and PP are mixed using different pattern. The morphology and the volume resistivity of the obtained composites are evaluated. Electrical conductivity investigation shows that the percolation threshold and resistivity values are dependent on the CB concentration. The best morphological observation shows that the PET phases forms well‐defined microfibrils, and CB particles overwhelmingly localize in the surfaces of the PET microfibrils, which led to a very low percolation threshold, i.e., 4.5 phr, and a reasonable conductivity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Crystalline and thermal behavior of poly(ethylene terephthalate)/polyphenoxy blends

Poly(ethylene terephthalate) (PET)/polyphenoxy blends were prepared by melt blending. Crystalline and thermal behaviors of PET/polyphenoxy blends were verified by use of DSC. The experiment results show that the initial temperature, peak temperature, and ending temperature of cold crystallization increase with increasing phenoxy content. On the contrary, the onset melting temperature, finishing melting temperature, and peak temperature in the first heating and the secondary heating processes decrease with increasing phenoxy content. The crystallization enthalpy and melting enthalpy, as well as the crystallization rate, decrease with increasing phenoxy content. Avrami exponents of the blends are slightly higher than that of pure PET and almost independent of phenoxy content. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 878–885, 2005     

Influence of the Addition of Tetrabutyl Orthotitanate on the Rheological,Mechanical, Thermal,and Morphological Properties of Polycarbonate/Poly(Ethylene terephthalate) Blends

The effects of the incorporation of tetrabutyl orthotitanate (TBOT) on the mechanical, thermal, rheological, and morphological properties of polycarbonate (PC)/ poly(ethylene terephthalate) PET blends were investigated. Blends were prepared using a screw extrusion with TBOT's rates varying from 0 to 0.25 phr. Rheological and mechanical investigations showed that the blends properties decreased by chain scissions induced by the degradation of PET and by volatile products release. Differential scanning calorimetry (DSC) revealed that the crystallinity of PET in PC/PET blends is affected by many parameters and does not depend only on PC and TBOT concentrations whereas dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM) support the occurrence of a little compatibilization.     

Processability,Structure and Mechanical Properties of Poly(ether imide)/Amorphous Copolyester Blends

Blends of PEI with an amorphous copolyester (PCTG) were obtained by melt‐mixing followed by injection molding. The processability of PEI increased several times upon addition of just 10% PCTG, thus expanding the applications of PEI. All the blends showed a single T_g and most of them were transparent. However, they were biphasic as suggested by the widening of the T_g's and proved by SEM. A fine dispersed particle size and good adhesion level were also observed by SEM. The values of the modulus of elasticity and the yield stress appeared close the additivity rule, and were attributed to the combined effects of the density increase and orientation decrease in the blends. These morphological changes had a slightly negative influence on ductility which was nevertheless high.

     

Phase Behaviour of Poly(ethylene oxide)/Poly(styrene-co-maleic anhydride) Blends

Thermal behaviour and morphology of blends of poly(ethylene oxide) (PEO) and poly(styrene-co-maleic anhydride) (SMA) prepared by the coprecipitation technique were studied by means of differential scanning calorimetry, optical microscopy and thermogravimetry. SMA containing 25wt% maleic anhydride (MA) was found to be miscible with PEO when the SMA content was greater than 80%. The melting temperature and crystallinity depended on the composition of the blend. SMA appears to segregate interlamellarly during the isothermal crystallization of PEO. The thermal stability of blends was enhanced and was higher than that of pure PEO and SMA. © of SCI.     

Spinning and properties of poly(ethylene terephthalate)/organomontmorillonite nanocomposite fibers

By in situ polycondensation, a intercalated poly(ethylene terephthalate)/organomontmorillonite nanocomposite was prepared after montmorillonite (MMT) had been treated with a water‐soluble polymer. This nanocomposite was produced to fibers through melt spinning. The resulting nanocomposite fibers were characterized by X‐ray diffraction (XRD), differential scanning calorimeter (DSC), and transmission electron microscopy (TEM). The interlayer distance of MMT dispersed in the nanocomposite fibers was further enlarged because of strong shear stress during processing of melt spinning. This was confirmed by XRD test and TEM images. DSC test results showed that incorporation of MMT accelerated the crystallization of poly(ethylene terephthalate) (PET), but the crystallinity of the drawn fibers just had a little increasing compared with that of neat PET drawn fibers. Also compared with pure PET drawn fibers, tensile strength at 5% elongation and thermal stability of the nanocomposite fibers were improved. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1443–1447, 2005     

聚丙烯/乙烯-辛烯-1共聚物共混体系流变性能研究

采用高级流变扩展系统(ARES)研究了聚丙烯(PP)/乙烯-辛烯共聚物共混体系的流变性能,探讨了乙烯-辛烯共聚物含量和 PP 种类对共混体系储能模量、剪切黏度和零切黏度的影响。实验结果显示,PP 结构和 POE 含量对 PP/POE 共混体系的剪切流变性能有显著影响,随着 POE 含量的增加,PP1/POE 共混体系的储能模量和剪切黏度增加的幅度明显小于 PP2/POE 共混体系,PP1/POE 共混体系和 PP2/POE 共混体系的储能模量和剪切黏度增加幅度较大分别发生在 POE 含量为20%～30%和10%～20%,即共混体系发生"脆—韧"转变阶段。PP/POE 共混体系中存在界面滑移现象,且 PP 和 POE 的界面相容性对界面滑移现象影响较大,其中 PP1/POE 的界面滑移比PP2/POE 的界面滑移更加明显。     

聚丁二酸丁二醇-共-对苯二甲酸丁二酯流变性能研究

采用毛细管流变仪研究了聚丁二酸丁二醇-共-对苯二甲酸丁二酯(PBST)的流变性能。结果表明:PBST熔体为切力变稀型流体,黏流活化能较低,具有较好的成纤性能。同时,讨论了相对分子质量、剪切速率、温度对PBST熔体流动曲线、非牛顿指数、结构黏度指数等的影响,为生物可降解性PBST纤维的生产工艺提供了理论依据。     

Microstructure and crystallization of melt‐mixed poly(ethylene terephthalate)/poly(ethylene isophthalate) blends

Physical blends of poly(ethylene terephthalate) (PET) and poly(ethylene isophthalate) (PEI), abbreviated PET/PEI (80/20) blends, and of PET and a random poly(ethylene terephthalate‐co‐isophthalate) copolymer containing 40% ethylene isophthalate (PET₆₀I₄₀), abbreviated PET/PET₆₀I₄₀ (50/50) blends, were melt‐mixed at 270°C for different reactive blending times to give a series of copolymers containing 20 mol % of ethylene isophthalic units with different degrees of randomness. ¹³C‐NMR spectroscopy precisely determined the microstructure of the blends. The thermal and mechanical properties of the blends were evaluated by DSC and tensile assays, and the obtained results were compared with those obtained for PET and a statistically random PETI copolymer with the same composition. The microstructure of the blends gradually changed from a physical blend into a block copolymer, and finally into a random copolymer with the advance of transreaction time. The melting temperature and enthalpy of the blends decreased with the progress of melt‐mixing. Isothermal crystallization studies carried out on molten samples revealed the same trend for the crystallization rate. The effect of reaction time on crystallizability was more pronounced in the case of the PET/PET₆₀I₄₀ (50/50) blends. The Young's modulus of the melt‐mixed blends was comparable to that of PET, whereas the maximum tensile stress decreased with respect to that of PET. All blend samples showed a noticeable brittleness. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3076–3086, 2003     

Barrier Properties of Blends Based on Liquid Crystalline Polymers and Poly(ethylene terephthalate)

Abstract

Blends of poly(ethylene terephthalate) (PETP) and two different thermotropic liquid crystalline (LC) polymers of the Vectra-type were prepared by melt mixing. Oxygen and water vapor permeability, light transmission and welding properties were measured on compression-molded and film-blown specimens. SEM showed that the LC polymers were the disperse phase with a good phase adhesion to the PETP matrix in the majority of the compression-molded blends. The 50/50 blend based on the low melting point LC polymer showed possibly a continuous LC polymer phase. The film-blown specimens showed LC polymer spheres at low LC polymer content. Above a certain LC polymer content (10-30% LC polymer), fibrous and ellipsoidal LC polymer particles was the dominant morphological feature of the blends. Density measurements showed that the void content in the blends was low. The compression-molded blends based on the high melting point LC polymer showed permeabilities conforming to the Maxwell equation assuming low permeability (LC polymer) spheres in a high permeability (PETP) matrix. The compression-molded blends based on the low melting point Vectra showed lower permeabilities than predicted by the Maxwell equation, particularly at high LC polymer content. The film-blown blends showed extensive scattering in the permeability data. The blend with 30% low melting LC polymer exhibited a 96% lower oxygen permeability than PETP. This was due to a reduction in both oxygen diffusivity and solubility. Ellipsoidal and fibrous LC polymer particles increased the diffusional path and lowered the diffusivity. The transparency of the compression-molded samples was lost already at 1% LCP. The blends showed welding properties superior to those of PETP.     

PET／POE-g-MAH的性能研究

利用熔融法，采用马来酸酐接枝乙烯-辛烯共聚弹性体(POE-g-MAH)增韧聚对苯二甲酸乙二醇酯(PET)，研究了热处理对PFT／POE-g-MAH共混体系增韧效果的影响。结合共混材料的室温缺口冲击断面SEM照片，淬断刻蚀照片和宏观力学性能，分析了共混体系发生脆韧转变对应的微观形貌特征。结果表明POE-g-MAH与PET具有良好的相容性，热处理不但可以使PET／POE-g-MAH共混体系的拉伸强度增大，而且可以显著提高其冲击强度。