原位微纤化EPS/CAB共混物的形态结构研究

采用熔融共混-热拉伸的方法制备了聚丙烯三元共聚物(EPS)/乙酸丁酸纤维素(CAB)原位微纤化共混物,通过扫描电子显微镜(SEM)表征了EPS微纤的结构形态,分析了共混物流变性能与微纤结构的关系。结果表明,EPS含量、螺杆转速和熔体粘度比对微纤的形态结构均有影响。     

Effect of nanoparticles on the morphology and properties of PET/PP in situ microfibrillar reinforced composites

In this work, the effect of SiO₂ nanoparticles on the morphology and properties of PET/PP in situ microfibrillar reinforced composites (MFC) obtained from slit die extrusion and hot stretching‐quenching was investigated. The scanning electron micrographs revealed that the nanoparticles could have different effects on microfibril formation of PET/PP MFC depending on their concentration. Addition of appropriate content of nanoparticles (e.g., 1.6 and 8 wt%) facilitated the PET droplet‐fibril transition during stretching due to the presence of nanosilica in the PP matrix, which increased the viscosity of PP matrix and then improved the droplet deformability. However, at higher loading (e.g., 12 wt%), the aggregation of silica nanoparticles around the PET droplets prevented disperse phase coalescence during drawing and then reduced the fibrillation ability of PET minor phase. The dynamic rheological test performed at 190°C showed that the increased spatial restriction of the nanoparticles improved the viscoelastic moduli and complex viscosity of PET/PP MFC. DSC results indicated that nanosilica had little heterogeneous nucleation effect on the PP matrix of PET/PP MFC. Additionally, nanoparticles could present drastic improvement in the degradation behavior of PET/PP MFC under thermo‐oxidative conditions and increased the modulus of PET/PP MFC. POLYM. COMPOS., 38:2718–2726, 2017. © 2015 Society of Plastics Engineers     

Morphology and mechanical properties of poly (phenylene sulfide)/isotactic polypropylene in situ microfibrillar blends

The morphology and mechanical properties of the in situ microfibrillar blend based on isotactic polypropylene (iPP) and poly (phenylene sulfide) (PPS) were examined. The microfibrillar PPS/iPP blend was prepared through a slit‐die extrusion, hot stretching, and water quenching process. Morphological observation indicated that the well‐defined PPS microfibrils were achieved by the method used in this study, which provided a promising method for both PPS and PP recycling. The morphology study showed that the minimum diameter of PPS phase was independent of PPS concentration. The diameter of most PPS fibrils in the microfibrillar blend was unexpectedly comparable to that of the PPS particles in the common blend at the same PPS content. The tensile strength of microfibrillar blend was higher than that of common blend, indicating the mechanical enhancement of microfibrillar processing to the PPS/iPP blend. The tensile strength of the microfibrillar blend also increased with stretching. POLYM. ENG. SCI., 45:1303–1311, 2005. © 2005 Society of Plastics Engineers     

Enhancement in the mechanical properties of in situ microfibrillar PLA/POE composites

In situ microfibrillar poly(lactic acid) (PLA)/polyolefin elastomer (POE) composites (MFCs) with and without compatibilizer POE-g-GMA were prepared using a multistage stretching equipment. The results showed that the distribution of PLA inside the POE matrix for the MFCs without compatibilizer was in the form of microfibrils, and most of the PLA microfibrils were well-oriented and arranged in the matrix. Further, the high PLA content was more likely to form longer PLA microfibrils in MFCs. With the increase in the amount of POE-g-GMA for (PLA/POE, 20/80) system, the length of PLA microfibrils significantly decreased, whereas the average diameter increased. The addition of 2 wt% POE-g-GMA increased the tensile strength and elongation at the break of POE-20-2 by 52.7% and 53.5%, respectively, and the crystallization temperature increased by about 4°C.     

Effect of in situ synthesized macroactivator on morphology of PA6/PS blends via successive polymerization

In situ polymerization and in situ compatibilization was adopted for preparation of ternary PA6/PS‐g‐PA6/PS blends by means of successive polymerization of styrene, with TMI and ε‐caprolactam, via free radical copolymerization and anionic ring‐opening polymerization, respectively. Copolymer poly(St‐g‐TMI), the chain of which bears isocyanate (? NCO), acts as a macroactivator to initiate PA6 chain growth from the PS chain and graft copolymer of PS‐g‐PA6 and pure PA6 form, simultaneously. The effect of the macroactivator poly(St‐g‐TMI) on the phase morphology was investigated in detail, using scanning electron microscopy. In case of blends with higher content of PS‐g‐PA6 copolymer, copolymer nanoparticles coexisting with the PS formed the matrix, in which PA6 microspheres were dispersed evenly as minor phase. The content of the compositions (homopolystyrene, homopolyamide 6, and PS‐g‐PA6) of the blends were determined by selective solvent extraction technique. The mechanical properties of PA6/PS‐g‐PA6/PS blends were better than that of PA6/PS blends. Especially for the blends T10 with lower PS‐g‐PA6 copolymer content, both the flexural strength and flexural modulus showed significantly improving because of the improved interfacial adhesion between PS and PA6. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Study on the phase behavior of EVA/PS blends during in situ polymerization

A triangular phase diagram of the polystyrene/styrene/ethylene vinyl‐acetate (PS/SM/EVA) system is established to account for the phase change during polymerization of SM. The phase behaviors for EVA and PS domains in the SM polymerization system are also studied by an optical microscope (OM) and a photometer. Both EVA and PS dissolve in SM quite easily, but PS and EVA are immiscible. Hence, the exclusion of PS from the EVA phase domain results during the polymerization. That is, the polymer solution will be phase‐separated at the initial stage of polymerization. Additionally, EVA phase inversion occurs as the conversion of SM increases to 15%, at which the volume ratio of EVA/PS is approximately unity. Monitoring the light transmittance level of EVA/PS/SM solution during polymerization, the EVA phase proves to have been completely inverted to the dispersed phase when the SM conversion reaches 20%.     

Study on the surface properties and morphology of blends of HDPE/PE-g-PDMS

Summary Film surface properties and morphology of blends of HDPE with PE-g-PDMS were studied by contact angle, ESCA and SEM measurements. All the results showed clearly the surface enrichment of PDMS segments on the film surface although the difference in the surface tension of the two components is smaller than that between PDMS and hydrophilic polymers. According to the SEM results, the PDMS segments were enriched on the surface in separate domains.     

ABS共混物界面形态研究方法

对研究ABS及ABS共混物界面形态方法进行了比较详细的论述，并对拟采用的研究ABS共混物界面的方法进行了分别论述。     

Rheological behavior comparison between PET/HDPE and PC/HDPE microfibrillar blends

The rheological behaviors of in situ microfibrillar blends, including a typical semicrystalline/semicrystalline (polyethylene terephthalate (PET)/high‐density polyethylene (HDPE)) and a typical amorphous/semicrystalline (polycarbonate (PC)/HDPE) polymer blend were investigated in this study. PET and PC microfibrils exhibit different influences on the rheological behaviors of microfibrillar blends. The viscosity of the microfibrillar blends increases with increased PET and PC concentrations. Surprisingly, the length/diameter ratio of the microfibrils as a result of the hot stretch ratio (HSR) has an opposite influence on the rheological behavior of the two microfibrillar blends. The stretched PET/HDPE blend exhibits higher viscosity than the unstretched counterpart, while the stretched PC/HDPE blend exhibits lower viscosity than the unstretched blend. The data obtained in this study will be helpful for constructing a technical foundation for the recycling and utilization of PET, PC, and HDPE waste mixtures by manufacturing microfibrillar blends in the future. POLYM. ENG. SCI., 45:1231–1238, 2005. © 2005 Society of Plastics Engineers     

反应挤出就地增容HDPE/PS合金

在单螺杆挤出机上,利用路易斯酸实现了大分子间的Friedel—Crafts烷基化反应。考察了不同催化剂体系、催化剂用量及工艺条件对合金性能的影响。结果显示：对于质量比为70．0：30．0的高密度聚乙烯／聚苯乙烯合金体系,通过反应挤出,可以就地生成接枝共聚物;苯乙烯单体的加入有利于接枝物的形成;加入0．8份AlCl3、0．5份苯乙烯单体,控制合适的螺杆温度以及螺杆转速为60r／min时,合金的综合性能较好。     

Study of masterbatch effect on miscibility and morphology in PET/HDPE blends

The present work studies the morphology in poly(ethylene-terephthalate)/polyethylene (PET/HDPE) polymer blends and its impact on blend properties. Mixing process in blend preparation is the important parameter for the type of obtained blend morphology and final blend properties, so two different mixing processes were used. In the first one, all components are mixed together while another one includes two step mixing procedure using two different types of masterbatch as compatibilizers for PET/HDPE system. Such blends can be considered in terms of PET polymer recycling in the presence of HDPE impurities in order to find suitable compatibilizers, which will enhance the interactions between these two polymers and represents the possible solution in recycling of heterogeneous polymer waste. The morphology of the studied PET/HDPE blends was inspected by scanning electron microscopy to examine the influence of the mixing process and various compositions on blends morphology, and interactions between PET and HDPE. The surface properties were characterized by contact angle measurements. The effect of the extrusion on the samples thermal behaviour was followed by DSC measurements. FTIR spectroscopy was used for the determination of interactions between blend constituents. It can be concluded that the type of mixing process and the carefully chosen compatibilizer are the important factors for obtaining the improved compatibility in PET/HDPE blends.     

Structure-property relationships of microfibrillar reinforced blends of linear polycondensates

Binary microfibrillar reinforced composites are obtained by melt-blending of poly(ethylene terephthalate) (PET) and polyamide 6 (PA6), as well as polyamide 66 (PA66) and PA6 (both 40/60 by wt) in the presence of a catalyst, followed by cold drawing of the bristle to about 3.5 times and annealing at 220 or 240C. The blends are studied by X-ray diffraction, scanning electron microscopy (SEM), light microscopy and static mechanical testing. SEM and light microscopy reveal different blend morphologies due to differences in the miscibility of the homopolymers: the PA66/PA6 blend is morphologically more homogeneous, than the PET/PA6 blend. Annealing at 240C results in preservation of the high orientation of PET and PA66 while the PA6 portions of the two blends are partially disoriented, much more for the PET/PA6 blend as concluded from the X-ray data. Annealing at 240C suggest also transreactions leading to the in situ generation of block copolymers in addition to the generated ones during blend mixing in the extruder which improve the compatibility of the blend components. These physical and chemical changes affect the mechanical properties of the fibrillar reinforced blends and composites. The Young's moduli (E) and tensile strength ( σ t ) of the drawn blends are 5-6 and 7-9 times higher than those of the asextruded samples. Heat treatment at 220C results in a slight (for PA66/PA6) and stronger (for PET'PA6 blend) decrease of the σ t while E remains unchanged. A stronger decrease of E in both blends and of σ t in PA66/PA6 sample has been observed after annealing at 240C. Nevertheless, E and σ t of the last samples are about 3 times higher than those for the neat PA6.     

Study of morphology influence on rheological properties of compatibilized TPU/SAN blends

The compatibilizing efficiency of three different compatibilizers on the thermoplastic polyurethane/styrene‐co‐acrylonitrile (TPU/SAN) blends properties was investigated after compatibilizer's incorporation via melt‐mixing. The compatibilizers studied were as follows: poly‐ε‐caprolactone (PCL) of different molecular weight (M_w), a mixture of polystyrene‐block‐polycaprolactone (PS‐b‐PCL) and polystyrene‐block‐poly (methyl methacrylate) (PS‐b‐PMMA), and a mixture of polyisoprene‐block‐polycaprolactone (PI‐b‐PCL) and polybutadiene‐block‐poly (methyl methacrylate) (PB‐b‐PMMA). In our study, the effect of 5 wt % added compatibilizers on TPU/SAN blends morphology was examined. The transmission electron microscopy (TEM) was used to study the morphology at different length scales and to determine the compatibilizer's location. Investigations showed the different improvement of properties, because of the different incorporation of compatibilizers in the polymer blend. The morphology influence on the rheological behavior of compatibilized blends was investigated with a stress‐controlled rheometer (Rheometric Dynamic Stress Rheometer, SR‐500). Different compatibilization activity was found for different system. It was also found that compatibilization activity of added compatibilizer strongly depends on the comaptibilizer's M_w. Blends compatibilized with PCL showed superior properties as compared with the other examined blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2303–2316, 2006     

Study on the morphology and properties of metallocene polyethylene and ethylene/vinyl acetate blends

Two commercial polymer materials, metallocene linear low density polyethylene (m‐LLDPE) and ethylene/vinyl acetate copolymer (EVA) have been used to form binary blends of various compositions. The mechanical properties, morphology, rheological behavior, dynamic mechanical properties, and crystallization of m‐LLDPE/EVA blends were investigated. It was found that with the addition of EVA, the fluidity and processability of m‐LLDPE were significantly improved, and the introduction of polar groups in this system showed no significant changes in mechanical properties at lower EVA content. As verified by morphology observation and differential scanning calorimetry analysis, miscible blends were formed within certain weight ratios. Dynamic mechanical property studies showed that flexibility of the blends was enhanced in comparion with pure m‐LLDPE, where the peak value of loss modulus shifted to lower temperature and its intensity was enhanced as EVA content increased, indicating the existence of more amorphous regions in the blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 905–910, 2004     

In situ microfibrillar blends and composites of polypropylene and poly (ethylene terephthalate): Morphology and thermal properties

Microfibrillar blends were prepared from polypropylene and poly (ethylene terephthalate) by extrusion followed by cold drawing. The draw ratio employed had a prominent effect on the aspect ratio of the microfibrils produced, as revealed by scanning electron microscopy. The subsequent isotropization step between the T_m of the polymers created microfibrillar composites with randomly oriented short microfibrils of poly (ethylene terephthalate). The X ray diffraction patterns of the microfibrillar blends were different from those of corresponding composites although the polypropylene phase in both exhibited predominantly the presence of α crystallites. The crystallization of the polypropylene phase was affected by the orientation and diameter of the poly (ethylene terephthalate) microfibrils. The short microfibrils in the microfibrillar composites were not effectual in hastening the crystallization of polypropylene. The thermal decomposition studies revealed the capability of microfibrillar blends to delay the degradation better than the microfibrillar composites.     

Phase morphology of PP/COC blends

Phase morphology of polymer blends PP/COC, where PP is polypropylene and COC is a copolymer of ethene and norbornene, was characterized by means of scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM). PP/COC blends were prepared by injection molding and their morphology was studied for six different compositions (90/10, 80/20, 70/30, 60/40, 50/50, and 25/75 wt %). The intention was to improve PP properties by forming COC cocontinuous phase, which should impart to the PP matrix higher stiffness, yield stress, and barrier properties. Surprisingly enough, all studied blends were found to have fibrillar morphology. In the 90/10, 80/20, and 70/30 blends, the PP matrix contained fibers of COC, whose average diameter increased with increasing COC fraction. In the 60/40 blend, the COC component formed in the PP matrix both fibers and larger elongated entities with PP fibers inside. The 50/50 blend was formed by COC cocontinuous phase with PP fibers and PP cocontinuous phase with COC fibers. In the 25/75 blend, PP fibers were embedded in the COC matrix. In all blends, the fibers had an aspect ratio at least 20, were oriented in the injection direction, and acted as a reinforcing component, which was proven by stress–strain and creep measurements. According to the available literature, the fibrous morphology formed spontaneously in PP/COC is not common in polymer blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 253–259, 2004     

Role of nanoclay in determining microfibrillar morphology development in PP/PBT blend nanocomposite fibers

In this work, a new and highly efficient method of surface-initiated free radical graft-polymerizations on the surfaces of silica gel particles was put forward, and the graft-polymerization of methacrylic acid (MAA) was conducted. This method was convenient, feasible and highly effective. Coupling agent ??-mercaptopropyltrimethoxysilane(MPTS) was first bonded onto the surfaces of silica gel particles, obtaining the modified particles MPTS-SiO₂, onto which mercapto groups were chemically attached, so a redox initiation system of graft-polymerization was constituted by the mercapto group on the surfaces of MPTS-SiO₂ particles and the cerium (IV) salt in the solution. And then the surface-initiated free radical graft-polymerization of MAA on the surfaces of silica gel particles was carried out, resulting in the grafted particles PMAA/SiO₂ with a very high grafting density (35?g/100?g) of PMAA. The grafted particles PMAA/SiO₂ were characterized by infrared spectrum (FTIR), scanning electron microscope (SEM) and thermogravimetric analysis (TGA). The effects of the main factors on the new surface-initiated graft polymerization were emphatically examined, and the corresponding mechanism of the graft-polymerization was investigated in depth. The experimental results show that the mercapto group-cerium salt system analogous to the hydroxyl group-cerium salt system, can also effectively initiate vinyl monomers to be graft-polymerized on the surfaces of solid particles, and furthermore, it is a highly effective surface-initiated graft-polymerization method. In this graft-polymerization system, several factors such as sulfuric acid concentration, the used amount of cerium salt and the reaction temperature affect the grafting density greatly. For the graft-polymerization of MAA, the appropriate reaction conditions are as follows: reaction time of 3?h, reaction temperature of 50?°C, cerium concentration of 5.0?×?10^?3?M, acid (H⁺ ion) concentration of 0.15?M and MAA concentration of 0.5?M.     

Developing electrically conductive polypropylene/polyamide6/carbon black composites with microfibrillar morphology

We have established that the PP/PA6/CB composite with 3D microfibrillar conducting network can be prepared in situ using melt spinning process. CB particles preferably were localized at the interface between polypropylene as the matrix and PA6 microfibrils, which act as the conducting paths inside the matrix. The percolation threshold of the system reduced when aspect ratio of the conducting phase was increased by developing microfibrillar morphology. The effect of annealing process on the conductivity of PP/PA6/CB composite with co‐ continuous and microfibrillar morphologies was studied. It was observed that, annealing process forces CB particles towards the interface (2D space) of PP and PA6 co‐continuous phases, and percolation threshold and critical exponent of classical percolation theory will be decreased, while the conductivity of conducting composite with microfibrillar morphology was not affected considerably by annealing process at temperatures either higher or lower than the melting point of the PA6 microfibrils. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Influences of hot stretch ratio on essential work of fracture of in‐situ microfibrillar poly(ethylene terephthalate)/polyethylene blends

An in‐situ microfibrillar blend based on poly(ethylene terephthalate) (PET) and polyethylene (PE) was fabricated through slit die extrusion, hot stretching, and quenching. The morphological characteristics of the PET phase, such as diameter and its distribution, which were observed after the matrix was etched away, appear to be dependent on the hot stretch ratio at a fixed blend composition. The increase of the hot stretching ratio makes the PET particles change from spheres and ellipsoids to rodlike particles, and finally to well‐defined microfibers. The fracture toughness of the in‐situ microfibrillar blend was evaluated using deeply double‐edge notched tension (DDENT) specimens according to the essential work of fracture procedure. Initially, the increase of hot stretch ratio makes the specific essential work of fracture (w_e) rise. A maximum we appears at 25.4. Further increase of hot stretch ratio causes a slightdecrease of w_e. On the other hand, it shows that lower hot stretch ratios make the specific non‐essential work of fracture (w_p) rise slightly. As it exceeds 6.4, w_p decreases substantially. It was believed that the characteristics of the PET domains were responsible for the fracture behaviors of the in‐situ microfibrillar blend. Polym. Eng. Sci. 44:2165–2173, 2004. © 2004 Society of Plastics Engineers.