Summary: The miscibility and crystallization behaviors of polyamide 6 (PA 6)/polytetrafluoroethylene (PTFE) blends, prepared via reactive extrusion, are systematically investigated by means of wide‐angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC), and dynamic mechanical thermal analysis (DMTA). WAXD measurements show that no co‐crystallization occurred between two components, while DSC and DMTA measurements suggest that a certain degree of miscibility between them might exist due to the formation of some copolymers during the reactive extrusion.
DMTA curves for the pure PA 6 sample and PA 6/PTFE blends with various compositions. 相似文献
Molten caprolactam, in which a polyamide copolymer (HPN) containing rigid segments was dissolved, was polymerized by means of anionic ROP to in produce polyamide (PA, nylon) 6 blends with HPN in situ. A novel molecular composite was achieved in which toughness and strength were simultaneously improved, as well as modulus, compared to virgin PA6. In view of the interchange reaction between PA6 and PA1212 (and PA66) in blends fabricated in the same way, it was deduced that a similar reaction between PA6 and HPN took place during the blending and led to copolymerization between the two components. The formation of copolymers was verified by their single glass transition and single melting peak, measured through DMA and DSC, respectively. DSC analysis also showed that the occurrence of the interchange reaction inhibited the crystallization and suppressed the melting point of PA6. Analysis by FT‐IR spectroscopy indicated that the difference in the distance between the amide groups for PA6 and HPN induced a decrease in the amount and strength of hydrogen bonding. Moreover, characterization by POM and XRD revealed that the spherulite size of the PA6 crystals decreased dramatically and the amount of γ crystal increased slightly with the majority of crystallites being α crystals. Furthermore, it was found through the observation of the morphology by SEM that no phase separation existed in the composites. On the basis of detailed analysis and a comparison between the in situ PA6/PA66 and PA6/HPN blends, it is believed that the combination of markedly decreasing spherulite size and similar segmental mobility resulted in the simultaneous improvement of mechanical properties for the in situ PA6/HPN blends.
Polyamide comprises one of the major classes of polymers. Layered silicates (nanofiller) may enhance properties of polyamide-based hybrids even at very low content. Aliphatic polyamides (nylons) have often been chosen for commercial applications because of excellent physical and chemical properties. Aromatic polyamides (aramids) and aliphatic-aromatic polyamides have been predominantly useful as high-performance materials due to stiffness, low density, and low cost. Recently polyamide blends have become an important route to high-performance materials. Binary blends of polyamide/polypropylene, polyamide/polystyrene, polyamide/polymethyl methacrylate, polyamide/polyurethane, and others have been reported for nanocomposite formation with organoclay. However, ternary blend nanocomposite with nanoclays (PA6/mSEBS, PA6/EPDM-g-MA/H-HDPE) is rarely explored. 相似文献
The effect of hydrophilic and hydrophobic nanosilica on the morphological, mechanical and thermal properties of polyamide 6 (PA) and poly(propylene) (PP) blends is investigated by extrusion compounding. Depending on the difference between the polymer/nanoparticle interfacial tensions, different morphologies are obtained as highlighted by TEM and SEM. Hydrophobic nanosilica migrates mainly at the PA/PP interface, which leads to a clear refinement of PP droplet size. The macroscopic properties of the hybrid blends are discussed and interpreted in relation with the blend morphology and melt‐mixing procedure. The control over coalescence allows a morphology refinement of the blends and improves mechanical properties.
Summary: Polyamide‐6 (PA6)/polyarylate of bisphenol A (PAr) blends rich in PA6 and modified with an additional 15% poly[ethylene‐co‐(methacrylic acid)] partially neutralized with zinc (PEMA‐Zn) as a compatibilizer were obtained by melt mixing. Their phase structure, morphology, and mechanical performance were compared with those of the corresponding binary blends. The ternary blends were composed of a PA6 amorphous matrix and a dispersed PAr‐rich phase in which reacted PA6 and PEMA‐Zn were present. Additionally, minor amounts of a crystalline PA6 phase, and a PEMA‐Zn phase were also present. The chemical reactions observed led to a clear decrease in the dispersed particle size when PEMA‐Zn was added, indicating compatibilization. Consequently, the mechanical behavior of the blends with PEMA‐Zn improved, leading, mainly in the case of the blend with 10% PAr, to significant increases in both ductility and impact strength with respect to those of the binary blends. These increases were more remarkable than the slight decrease in stiffness as a consequence of the rubbery nature of the compatibilizer.
Cryogenically fractured surface of the PA6/PAr‐PEMA‐Zn 70/30‐15 ternary blend. 相似文献
Polypropylene/Polyamide 6 (PP/PA6) blends-TiO2 nanocomposites have been prepared via melt blending PP/PA6 with TiO2 nanoparticles, which were pretreated with toluene-2,4-di-isocyanate. The functionalized-TiO2 can react with the terminal amino and carboxyl groups at PA6, interfacial interaction and compatibility between TiO2 and matrix have been greatly improved resulted in higher tensile and impact strength than that of those filled with pristine TiO2 or pure PP/PA6 blends, and they have strong antimicrobial abilities against Bacillus subtilis, Staphylococcus aureus and Escherichia coli. The average efficiency of antibacterial is over 90% within 2.0 h. Mechanical and antibacterial properties can achieve their maximum with 3.0 wt%TiO2. 相似文献
In this study, polyamide 6/polystyrene in situ microfibrillar blends are prepared via anionic polymerization of ε‐caprolactam in a twin screw extruder. Scanning electron microscope analysis reveals that microfibrillated PA6 dispersed phase, which is continuous and preferentially oriented parallel to the extrusion direction, is in situ formed within polystyrene (PS) matrix during reactive extrusion at the content PS equal to 30 and 40 wt%. Mechanical properties analysis shows that the yield strength and elongation at break of PA6/PS (70/30 and 60/40) microfibrillar blends are remarkably increased with respect to those of pure PS. Also, the in situ fibrillation mechanisms are investigated by the analysis of morphological evolution. This work demonstrates a facile and efficient route to fabricate the microfibrillar blends with relatively high contents of polymer microfibrils.
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