磨盘碾磨制备PA6/PP/SBS共混物的结构与性能

采用磨盘形力化学反应器,在室温下制备了PA6/PP超细混合粉体,与SBS共混制得PA6/PP/SBS共混物,测定了材料的力学性能并用TEM研究了材料在不同加工温度下相结构的变化.结果表明,通过固相力化学粉碎制备的PA6/PP混合微粉,改善了PA6与PP和SBS的相容性,促进了PA6及PP的分散和与SBS的相界面结合.在微粉填充量为4%～8%(质量分数)时,材料的拉伸强度大幅度提高,扯断伸长率保持不变.加工温度变化引起材料相结构的变化对材料性能产生显著影响.在PP熔融温度下加工,PP粒子产生粘连形成链状结构,可提高材料的力学性能.     

Effects of SEBS-g-BTAI on the morphology, structure and mechanical properties of PA6/SEBS blends

Styrene-b-(ethylene-co-1-butene)-b-styrene (SEBS) triblock copolymer functionalized with ε-caprolactam blocked allyl (3-isocyanate-4-tolyl) carbamate (SEBS-g-BTAI) was used to toughen polyamide 6 (PA6) via reactive blending. Compared to the PA6/SEBS blends, mechanical properties such as tensile strength, Young’s modulus, especially Izod notched strength of PA6/SEBS-g-BTAI blends were improved distinctly. Both rheological and FTIR results indicated a new copolymer formed by the reaction of end groups of PA6 and isocyanate group regenerated in the backbone of SEBS-g-BTAI. Smaller dispersed particle sizes with narrower distribution were found in PA6/SEBS-g-BTAI blends, via field emitted scanning electron microscopy (FESEM). The core-shell structures with PS core and PEB shell were also observed in the PA6/SEBS-g-BTAI blends via transmission electron microscopy (TEM), which might improve the toughening ability of the rubber particles.     

Does nanoclay addition always lead to amelioration? Dual effects of the nanoclay on the PA‐6/EVOH/SEBS ternary blends

This work presents the investigation of properties of polyamide‐6 (PA‐6)/ethylene vinyl alcohol (EVOH)/styrene‐ethylene‐butylene‐styrene (SEBS) ternary blends and related nanocomposites with nanoclays. In this way, the effect of the mixing protocol and nanoclay type on the morphology, mechanical, and rheological properties of the blends was comprehensively studied. Scanning electron microscopy (SEM) observation revealed that, for the neat ternary blends, core‐shell droplets were formed in which SEBS droplets were encapsulated by EVOH phase in the PA‐6 matrix. In this regard, experimental observations were compared and discussed with the predictions of phenomenological models. According to the X‐ray diffraction analysis, the distribution and degree of dispersion of the nanoclays were significantly influenced by mixing protocol. It was demonstrated that competition between the intrinsic effect of the nanoclay on the physical properties and its inhibiting effect on the interactions between PA‐6 and EVOH phases led to some interesting observations for the rheological and mechanical properties of the ternary blends. The results revealed that optimum properties could be obtained by selecting appropriate nanoclay and mixing protocol.     

显微镜图像分析研究聚丙烯/尼龙1010共混物相结构及其性能

用扫描电子显微镜图像分析研究了聚丙烯/聚酰胺1010共混物及其部分相容体系的相形态结构,计算了表征相结构和尺寸的结构参数,如分散相的平均直径、平均弦长和分散相的质心相关距等.并分别讨论了聚丙烯/聚酰胺1010共混物及其部分相容体系的相形态以及其结构参数与共混物组成的关系.测定了聚合物及其共混物体系的力学性能,讨论了共混物组成与力学性能的关系.聚丙烯/聚酰胺1010共混物的拉伸模量与组成的关系较为复杂,但其部分相容体系的拉伸模量与组成呈线性关系.聚丙烯/聚酰胺1010及其共混物体系的屈服强度与共混物组成均呈线性关系.表征相结构的两相平均弦长比(l-1/-l2)与组成以及共混物体系力学性能与组成的关系,二者相似.同时讨论了体系力学性能随相尺寸等的变化规律.     

Influence of Reactive Compatibilization on the Melt Flow Properties and Morphology of Polyamide 6/Styrene-Acrylonitrile Blends

Summary: In this study, we investigate the influence of reactive compatibilization on the rheological properties of polyamide 6/styrene-acrylonitrile (PA 6/SAN) blends in the melt. Linear viscoelastic shear oscillations, simple elongation to a large stretch ratio and subsequent recovery experiments were performed. The morphology of the blends was examined by atomic force microscopy. We prepared three PA 6/SAN blends with different composition ratios of PA 6 and SAN (70/30, 50/50, 30/70) and a constant concentration of the reactive agent. Our experiments revealed that reactive compatibilization significantly increases the complex modulus of PA 6/SAN blends at low frequencies. In particular, the data of the PA 6/SAN 50/50 blend and the PA 6/SAN 30/70 blend indicated that an elastic network between neighbouring PA 6 domains was formed. In simple elongation, the transient elongational viscosity of the blends exceeded the values of the single components. In recovery, the recovered stretch of all blends was larger than the recovered stretch of the pure components. The differences of the blend morphology and of the linear viscoelastic behaviour were qualitatively explained by the asymmetric properties of the reactively compatibilized interface.     

Evaluation of the SEBS copolymer in the compatibility of PP/ABS blends through mechanical,thermal, thermomechanical properties,and morphology

Polypropylene (PP) blends with acrylonitrile-butadiene-styrene (ABS) were prepared using the styrene-ethylene-butylene-styrene copolymer (SEBS) as a compatibilizing agent. The blends were prepared in a co-rotational twin-screw extruder and injection molded. Torque rheometry, Izod impact strength, tensile strength, heat deflection temperature (HDT), differential scanning calorimetry, thermogravimetry, and scanning electron microscopy properties were investigated. The results showed that there was an increase in the torque of PA6/ABS blends with SEBS addition. The PP/ABS/SEBS (60/25/15%) blend showed significant improvement in impact strength, elongation at break, thermal stability, and HDT compared with neat PP. The elastic modulus and tensile strength have not been significantly reduced. The degree of crystallinity and the crystalline melting temperature increased, indicating a nucleating effect of ABS. The PP/ABS blends compatibilized with 12.5% and 15% SEBS presented morphology with well-distributed fine ABS particles with good interfacial adhesion. As a result, thermal stability has been improved over pure PP and the mechanical properties have been increased, especially impact strength. In general, the addition of the SEBS copolymer as the PP/ABS blend compatibilizer has the advantage of refining the blend's morphology, increasing its toughness and thermal stability, without jeopardizing other PP properties.     

PA66/PA12/clay based nanocomposites: morphology and physical properties

The structure and the physical properties of several polyamide 66 (PA66)/polyamide 12 (PA12) blends containing different amounts of the two polymers and obtained by melt‐blending have been investigated. A low amount of organically‐modified layered silicate (OMLS, 4 wt%) has also been introduced in order to further improve the physical properties and, in particular, to evaluate its effect on the blends' structure and components' miscibility. The microstructure and morphology of all the composites were analyzed by means of X‐Ray diffraction (WAXD), transmission electron microscopy (TEM), and high resolution scanning electron microscopy (SEM), while the macroscopic scale properties (mechanical behavior and water adsorption) were assessed in order to investigate and understand the materials' structure–properties relationships. The partial miscibility of PA66 and PA12, with phase separation depending on blend composition, has been confirmed. The results also underlined the possibility to tailor the behavior of polymer blends in terms of mechanical water adsorption properties by varying the amount of PA12, added to PA66 with and without the addition of the OLMS. The effectiveness of the clay in modifying the components' miscibility as well as its tendency to segregate preferentially within separate PA66 domains have been assessed. WAXD results showed opposite effects of PA12 and clay on the crystallization behavior of PA66, an aspect that has also been deepened in another paper by the same authors discussing the results of the complete thermal characterization. Copyright © 2010 John Wiley & Sons, Ltd.     

Influence of SEBS-g-MA on morphology, mechanical, and thermal properties of PA6/PP/organoclay nanocomposites

Polyamide 6/polypropylene (PA6/PP = 70/30 parts) blends containing 4 phr (parts per hundred resin) of organically modified clay (organoclay) toughened with maleated styrene-ethylene-butylene-styrene (SEBS-g-MA) were prepared by melt compounding using co-rotating twin-screw extruder followed by injection molding. X-ray diffraction (XRD) and transmission electron microscope (TEM) were used to characterize the structure of the nanocomposites. The mechanical properties of the nanocomposites were determined by tensile, flexural, and notched Izod impact tests. The single edge notch three point bending test was used to evaluate the fracture toughness of SEBS-g-MA toughened PA6/PP nanocomposites. Thermal properties were studied by using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). XRD and TEM results indicated the formation of the exfoliated structure for the PA6/PP/organoclay nanocomposites with and without SEBS-g-MA. With the exception of stiffness and strength, the addition of SEBS-g-MA into the PA6/PP/organoclay nanocomposites increased ductility, impact strength and fracture toughness. The elongation at break and fracture toughness of PA6/PP blends and nanocomposites were increased with increasing the testing speed, whereas tensile strength was decreased. The increase in ductility and fracture toughness at high testing speed could be attributed to the thermal blunting mechanism in front of crack tip. DSC results revealed that the presence of SEBS-g-MA had negligible effect on the melting and crystallization behavior of the PA6/PP/organoclay nanocomposites. TGA results showed that the incorporation of SEBS-g-MA increased the thermal stability of the nanocomposite.     

Impact properties,phase structure,compatibility, and fracture morphology of polyamide‐1010/thermoplastic poly(ester urethane) elastomer blends

Blends of polyamide‐1010 (PA1010) and a thermoplastic poly(ester urethane) elastomer (TPU) were prepared by melt extrusion. The impact properties, phase structure, compatibility, and fracture morphology under impact were investigated for PA1010/TPU blends. The results indicated that TPU enhanced the impact strength of PA1010, and the best impact modification effect of the blends was obtained with 20 wt % TPU. The phase structure was investigated with scanning electron microscopy, and the compatibility was investigated with dynamic mechanical analysis and small‐angle X‐ray scattering. The study of the fracture morphology of PA1010/TPU blends indicated that the fracture surface of the blends had special features, consisting of many fibrillar elastomer particles and a conglutination–multilayer structure, as well as many small tubers on this structure. These fracture phenomena could not be found on the fracture surface of pure PA1010. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1177–1185, 2005     

The compatibilization effect of ethylene/styrene interpolymer on polystyrene/polyethylene blends

In this study, ethylene/styrene interpolymer (ESI) was used as compatibilizer for the blends of polystyrene (PS) and low‐density polyethylene (LDPE). The mechanical properties including impact, tensile properties, and morphology of the blends were investigated by means of uniaxial tension, instrumented falling‐weight impact measurements, and scanning electron microscopy. Impact measurements indicated that the impact strength of the blends increases slowly with LDPE content up to 40 wt %; thereafter, it increases sharply with increasing LDPE content. The impact energy of the LDPE‐rich blends exceeded that of pure LDPE, implying that the LDPE polymer can be further toughened by the incorporation of brittle PS minor phase in the presence of ESI. Tensile tests showed that the yield strength of the PS/LDPE/ESI blends decreases considerably with increasing LDPE content. However, the elongation at break of the blends tended to increase significantly with increasing LDPE content. The compatibilization efficiency of ESI and polystyrene‐hydrogenated butadiene‐polystyrene triblock copolymers (SEBS) for PS/LDPE 50/50 was further compared. Mechanical properties show that ESI is more effective to achieve a combination of LDPE toughness and PS rigidity than SEBS. The correlation between the impact property and morphology of the ESI‐compatibilized PS/LDPE blends is discussed. The excellent tensile ductility of the LDPE‐rich blends resulted from shield yielding of the matrix. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2136–2146, 2007     

Effect of electron beam irradiation on mechanical and thermal properties of waste polyamide copolymer blended with nitrile‐butadiene rubber

In the present study, the effect of electron beam irradiation on the morphological, thermal, and mechanical properties of waste polyamide copolymer (WPA‐66/6) blended with different contents of acrylonitrile butadiene rubber (NBR) were studied. The prepared blends were subjected to irradiation doses up to 150 kGy and the structural modifications were discussed; non‐irradiated blends were used as control. Mechanical properties, namely, tensile strength (TS), yield strength, elongation at break, and hardness, were followed up as functions of irradiation dose and degree of loading with rubber content. On the other hand, the influence of irradiation dose on the thermal parameters, melting temperature, heat of fusion, ΔH_m of the recycled PA copolymer, and its blend with NBR were also investigated. Copyright © 2009 John Wiley & Sons, Ltd.     

Effect of maleic anhydride-grafted ethylene-propylene rubber on the mechanical, rheological and morphological properties of organoclay reinforced polyamide 6/polypropylene nanocomposites

Polyamide 6/polypropylene (PA6/PP = 70/30 parts) blends containing 4 phr (parts per hundred resin) of organophilic modified montmorillonite (organoclay) were compatibilized with maleic anhydride-grafted ethylene-propylene rubber (EPRgMA). The blends were melt compounded in twin screw extruder followed by injection molding. The mechanical properties of PA6/PP nanocomposites were studied by tensile and flexural tests. The microstructure of the nanocomposite were assessed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The dynamic mechanical properties of the PA6/PP blend-based nanocomposites were analyzed by using a dynamic mechanical thermal analyzer (DMTA). The rheological properties were conducted from plate/plate rheometry via dynamic frequency sweep scans. The melt viscosity in a high shear rate region was performed by using a capillary rheometer. The strength and stiffness of the PA6/PP-based nanocomposites were improved significantly with the incorporation of EPRgMA. Adding EPRgMA to the PA6/PP blends resulted in a finer dispersion of the PP phase. TEM and XRD results revealed that the organoclay was dispersed more homogeneously in the presence of EPRgMA, however, mostly in the PA6 phase of the blends. DMTA results showed that EPRgMA worked as an effective compatibilizer. The storage (G′) and loss moduli (G″) assessed by plate/plate rheometry of PA6/PP blends increased with the incorporation of EPRgMA and organoclay. Furthermore, the apparent shear viscosity of the PA6/PP blend increased significantly for the EPRgMA compatibilized PA6/PP/organoclay nanocomposite. This was traced to the formation of an interphase between PA6 and PP (via PA6-g-EPR) and effective intercalation/exfoliation of the organoclay.     

剪切作用下马来酸酐接枝乙烯-辛烯共聚物和乙烯-丙烯酸丁酯-甲基丙烯酸缩水甘油酯共聚物对PA1010/PP共混物的增容作用比较

采用熔体共混的方法制备了两种增容剂增容的聚酰胺1010/聚丙烯(PA1010/PP)共混物,通过扫描电镜(SEM)、力学性能和差示扫描量热(DSC)测试,对动态保压注射成型(动态)和普通注射成型(静态)中增容剂POE-g-MAH(马来酸酐接枝乙烯-辛烯共聚物)和PTW(乙烯-丙烯酸丁酯-甲基丙烯酸缩水甘油酯共聚物)对PA1010/PP共混物的增容作用进行了比较研究.研究结果表明,普通注射成型中,PTW增容体系具有更小的分散相粒子,在DSC测试中出现两个结晶峰,即出现异相成核结晶和均相成核结晶,具有更好的拉伸和冲击性能,增容作用更佳.动态保压注射成型中施加剪切可以提高所有共混物的拉伸强度、拉伸模量和缺口冲击强度,PTW和POE-g-MAH两种增容剂增容体系冲击性能相近,但POE-g-MAH增容体系的分散相相区尺寸减小明显、分布均匀性显著增加,材料冲击强度增加幅度更大,表明剪切更有利于POE-g-MAH增容作用的进行.两种增容剂增容作用的不同源于它们化学组成的不同引起的材料形态差别.     

Miscibility-structure-property correlation in blends of ethylene vinyl alcohol copolymer and polyamide 6/66

Blends of ethylene vinyl alcohol (EVOH; 44 mol% ethylene) and polyamide 6/66 (PA; 75 mol% PA 6) random copolymers were studied in the entire composition range. Specific interaction between the components was analyzed by IR spectroscopy; furthermore, coefficients related to the Flory-Huggins interaction parameter were derived from equilibrium water uptake and tensile strength. Morphology of the blends was investigated by thermal analysis (DSC), density measurements, and SEM micrographs. The two polymers form heterogeneous blends in each composition. Although the components crystallize in separate phases, the morphology and the mechanical properties are greatly affected by the association of OH and NH groups. Crystallization is restricted in the blends, and the increase of the amorphous fraction, as well as specific interaction between the components, results in essential improvement in the mechanical properties.     

Maleic Anhydride Polyethylene Octene Elastomer Toughened Polyamide 6/Polypropylene Nanocomposites: Mechanical and Morphological Properties

A series of polyamide 6/polypropylene (PA6/PP) blends and nanocomposites containing 4 wt% of organophilic modified montmorillonite (MMT) were designed and prepared by melt compounding followed by injection molding. Maleic anhydride polyethylene octene elastomer (POEgMAH) was used as impact modifier as well as compatibilizer in the blend system. Three weight ratios of PA6/PP blends were prepared i.e. 80:20, 70:30, and 60:40. The mechanical properties of PA6/PP blends and nanocomposite were studied through flexural and impact properties. Scanning electron microscopy (SEM) was used to study the microstructure. The incorporation of 10 wt% POEgMAH into PA6/PP blends significantly increased the toughness with a corresponding reduction in strength and stiffness. However, on further addition of 4 wt% organoclay, the strength and modulus increased but with a sacrifice in impact strength. It was also found that the mechanical properties are a function of blend ratio with 70:30 PA6/PP having the highest impact strength, both for blends and nanocomposites. The morphological study revealed that within the blend ratio studied, the higher the PA6 content, the finer were the POEgMAH particles.     

Polyamide‐6/natural clay mineral nanocomposites prepared by solid‐state shear milling using pan‐mill equipment

The polyamide‐6 (PA6)/natural clay mineral nanocomposites were successfully prepared by solid‐state shear milling method without any treatment of clay mineral and additives. PA6/clay mixture was pan‐milled to produce PA6/clay compounding powder, using pan‐mill equipment. The obtained powder as master batch was diluted with neat PA6 to prepare composites by a twin‐screw extruder. The clay silicate layers were found to be partially exfoliated and dispersed homogeneously at nanometer level in PA6 matrix. The rheological measurements and mechanical properties of nanocomposites were characterized. The shear viscosities of nanocomposites were higher than that of pure PA6, and tensile strength and tensile modulus increased, but Izod impact strength decreased, with increasing concentration of clay. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 249–255, 2006     

Morphology and properties of ternary polyamide 6/polyamide 66/elastomer blends

The aim of the work presented is to evaluate the mechanisms and phase interactions in ternary blends based on different polyamides and functionalised elastomers, and to establish a correlation between the morphology controlled by the specific binary interactions, and physical and technological properties, respectively. The properties of the ternary system polyamide 6/polyamide 66/ elastomer depend on the specific blend morphology which is determined mainly by the differences of the surface tension of the components. A phase‐in‐phase structure was observed by microscopic study (AFM) in the ternary polyamide 6/polyamide 66/elastomer blends with maleic anhydride grafted ethene‐octene copolymer, and a “quasi” phase‐in‐phase structure in blends with maleic anhydride grafted ethene‐propene‐diene copolymer as the elastomer phase. An incorporation of polyamide inside of the elastomer particles was observed in the first case due to the difunctionality of polyamide 66. This type of morphology causes an increased elongation at break and toughness of these blends. In comparison to the binary polyamide based blends the ternary blends show an increased elastic modulus, elongation at break and yield stress as well as a high impact strength at low temperatures up to ?20 °C. Copyright © 2003 John Wiley & Sons, Ltd.     

Molecular dynamics and mechanical properties correlations of PA6/PPO blends compatibilized with SMA

The effects of the compatibilizer, styrene maleic anhydride (SMA‐8% MA) upon the change of morphology and molecular dynamics of polyamide‐6 (PA6) and poly (2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) blends were investigated by means of solid‐state NMR techniques. With increasing amounts of SMA, the domains correspond to PA6 and PPO are reduced and the polymer segmental mobility increased. The correlation between NMR relaxation time, T, and the bulk mechanical properties provide a molecular level understanding of the modification of molecular dynamics by the compatibilizer (SMA). The correlation shows that the tensile strength is governed mainly by the morphology, but modulated by the PA6 crystallinity, while the tensile elongation and impact strength are closely affected by both the molecular mobility and morphology. The annealing process improved only the tensile strength, but deteriorated tensile elongation and impact strength due to the increase of PA6 crystallinity, which induced phase separation after annealing. This study raised an important point that the polymer mechanical properties are most sensitive to the molecular structure and dynamics take place within the range of 20 Å to few hundred Å. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 1155–1163, 1999     

Rheology, morphology and mechanical properties of polyethylene/ethylene vinyl acetate copolymer (PE/EVA) blends

Rheology, morphology and mechanical properties of binary PE and EVA blends together with their thermal behavior were studied. The results of rheological studies showed that, for given PE and EVA, the interfacial interaction in PE-rich blends is higher than EVA-rich blends, which in turn led to finer and well-distributed morphology in PE-rich blends. Using two different models, the phase inversion composition was predicted to be in 45 and 47 wt% of the PE phase. This was justified by morphological studies, where a clear co-continuous morphology for 50/50 blend was observed. The tensile strength for PE-rich blends showed positive deviation from mixing rule, whereas the 50/50 blend and EVA-rich blends displayed negative deviation. These results were in a good agreement with the results of viscoelastic behavior of the blends. The elongation at break was found to follow the same trend as tensile strength except for 90/10 PE/EVA blend. The latter was explained in terms of the effect of higher co-crystallization in 90/10 composition, which increased the tensile strength and decreased the elongation at break in this composition. The results of thermal behavior of the blends indicated that the melting temperatures of PE and EVA decrease and increase, respectively, due to the dilution effect of EVA on PE and nucleation effect of PE on EVA.     

Mechanical properties of polymer‐blend nanocomposites with organoclays: Polystyrene/ABS and high impact polystyrene/ABS

Thirty‐three polystyrene (PS)/acrylonitrile‐butadiene‐styrene (ABS) and high impact PS/ABS polymer blends with organoclay and copolymer additives were prepared by melt processing using different mixing sequences in order to test the putative capability of clay to perform a compatibilizing role in polymer blends. In general, the addition of clay increased the tensile modulus and had little effect on tensile strength. For the blends studied in this work, the addition of organoclays caused a catastrophic reduction in impact strength, a critical property for commercial viability. The polymer‐blend nanocomposites adopted a structure similar to that for ABS/clay nanocomposites as determined by X‐ray diffraction and transmission electron microscopy. It is suggested that clay reinforcement inhibits energy absorption by craze formation and shear yielding at high strain rates. Simultaneous mixing of the three components provided nanocomposites with superior elongation and energy to failure compared to sequential mixing. The clay pre‐treated with a benzyl‐containing surfactant gave the best overall properties among the various organoclays tested and of the two clay contents studied 4 wt % was preferred over 8 wt % addition. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011