Distribution by Scientific Domains
Distribution within Polymers and Materials Science

Kinds of Polyamide

  • aromatic polyamide
  • soluble polyamide

  • Terms modified by Polyamide

  • polyamide chain

  • Selected Abstracts

    A Novel Approach to the Preparation of Nanoblends of Poly(2,6-dimethyl-1,4-phenylene oxide)/Polyamide 6

    Yali Ji
    Abstract Summary: A novel approach of in situ polymerization and in situ compatibilization was adopted to prepare poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and polyamide 6 (PA6) nanoblends. Anionic ring-opening polymerization of , -caprolactam was carried out in the presence of PPO, the chain of which bore p -methoxyphenylpropionate (MPAA), acting as macroactivator to initiate PA6 chain growth from the PPO chain and form a graft copolymer of PPO and PA6 and pure PA6 simultaneously. The nanostructured PA6 dispersed phase in the PPO matrix could be achieved. A TEM image of poly(2,6-dimethyl-1,4-phenylene oxide)/polyamide 6 nanoparticles obtained from in situ polymerization and in situ compatibilization. [source]

    Characterization of HDPE /Polyamide 6/ Nanocomposites Using Scanning-and Transmission Electron Microscopy

    Eleonora Erdmann
    Abstract Summary: Preparation and morphology of high density polyethylene (HDPE)/ polyamide 6 (PA 6)/modified clay nanocomposites were studied. The ability of PA 6 in dispersing clays was used to prepare modified delaminated clays, which were then mixed with HDPE. Mixing was performed using melt processing in a torque rheometer equipped with roller rotors. After etching the materials with boiling toluene and formic acid at room temperature, the morphology was examined by SEM analyses, showing that the PA 6 formed the continuous phase and HDPE the dispersed phase. X-ray diffraction patterns show that the (001) peak of the clay is dramatically decreased and shifted to lower angles, indicating that intercalated/exfoliated nanocomposites are obtained. TEM analyses confirmed the typical structure of exfoliated nanocomposites. A scheme for the mechanism of exfoliation and/or intercalation of these HDPE /PA 6/ /organoclay nanocomposites is proposed. [source]

    A Novel Approach to the Preparation of Nanoblends of Poly(2,6-dimethyl-1,4-phenylene oxide)/Polyamide 6

    Yali Ji
    Abstract Summary: A novel approach of in situ polymerization and in situ compatibilization was adopted to prepare poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and polyamide 6 (PA6) nanoblends. Anionic ring-opening polymerization of , -caprolactam was carried out in the presence of PPO, the chain of which bore p -methoxyphenylpropionate (MPAA), acting as macroactivator to initiate PA6 chain growth from the PPO chain and form a graft copolymer of PPO and PA6 and pure PA6 simultaneously. The nanostructured PA6 dispersed phase in the PPO matrix could be achieved. A TEM image of poly(2,6-dimethyl-1,4-phenylene oxide)/polyamide 6 nanoparticles obtained from in situ polymerization and in situ compatibilization. [source]

    Design of Blends with an Extremely Low Viscosity Ratio between the Dispersed and Continuous Phases.

    Dependence of the Dispersed Phase Size on the Processing Parameters
    Abstract Summary: This work deals with the development of the dispersed phase morphology in immiscible blends of poly(ethylene glycol)/polyamide 66 (PEG/PA) with an extremely low viscosity ratio. The blends were obtained, under different operating conditions, by melt blending in an internal mixer. The objective was to examine the influence of the main processing parameters on the particles size of the minor phase (PEG). A model was elaborated to describe the dependence of the particle size on interfacial tension, PEG concentration, shear rate and viscosity ratio between the two blend components. [source]

    Studies on Molecular Composites of Polyamide 6/Polyamide 66

    Yulin Li
    Abstract Summary: A series of molecular composites of PA 6/PA 66 was synthesized via in situ polymerization. The impact resistance of PA 6 was improved dramatically by incorporating a minor amount of PA 66 (2,10 wt.-%), without decreasing the tensile strength. Inserting PA 66 macromolecules at a molecular level into a PA 6 matrix may interfere with the arrangement of the hydrogen bonds of PA 6, in turn changing the crystalline structure and impeding the crystallization of PA 6. SEM micrograph of the fractured surface of a PA 6/PA 66 composite containing 10 wt.-% PA 66. [source]

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

    D. Tomova
    Abstract 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. [source]

    Interaction of a phosphorus-based FR, a nanoclay and PA6,Part 1: Interaction of FR and nanoclay

    FIRE AND MATERIALS, Issue 6 2009
    Alwar Ramani
    Abstract The thermal decomposition of organophosphorus fire-retardant (OP1311) and/ or organonanoclay (Cloisite 30B) is hereby investigated employing thermogravimetric analysis (TGA), to give an insight into their intrinsic behaviour and interaction in polymer nanocomposites for fire safety applications, because the addition of OP1311 and Cloisite 30B in Polyamide 6 (PA6) seems to have a synergistic effect on the thermal decomposition of PA6 (part 2 of the paper). An important objective of this research was to determine to what extent phosphorus components escape in the gaseous phase, which will affect the heat of combustion of the fire-retarded polymer. The decomposition products arising from pyrolysis and combustion are investigated by means of Fourier transform infrared spectroscopy. Under pyrolytic conditions, the inclusion of Cloisite 30B into OP1311 (FR) shows a synergistic effect on the initial mass loss at low temperature of ,280,420°C and leads to the acceleration of the thermal degradation process. While the DTG curve of Cloisite 30B shows two distinct degradation peaks (steps) that of OP1311 and OP1311 plus Cloisite 30B show four degradation steps. TGA measurements of OP1311 in nitrogen show more mass loss than in air, whereas Cloisite 30B gives similar amounts of mass loss in air and nitrogen. In nitrogen, the major evolved gaseous species from Cloisite 30B alone are hydrocarbons, 2-(diethylamino)ethanol and water, whereas the evolved gases from that of OP1311 at ,320°C are mainly water, at ,420°C, carbon dioxide, water and ammonia and at 480,570°C diethylphosphinic acid. Under thermo-oxidative conditions, the gases evolved are mainly carbon dioxide and water from both Cloisite 30B and OP1311. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    Comparison of polyamide 66,organoclay binary and ternary nanocomposites

    Miray Mert
    Abstract Polyamide 66,Lotader® 2210 blends (95/5 w/w), polyamide 66,Cloisite® 15A binary nanocomposites (98/2 w/w), and polyamide 66,Lotader® 2210,Cloisite® 15A ternary nanocomposites (93/5/2 w/w) were prepared by twin-screw extrusion, and the changes in mechanical properties, morphology, and flow properties of the materials prepared by different mixing sequences were investigated in this study. Lotader® 2210, which is a random terpolymer of ethylene, butyl acrylate, and maleic anhydride, was used as the impact modifier for polyamide 66 blends as well as polyamide 66 based nanocomposites. The best dispersion level, highest mechanical properties, highest viscosity values, and smallest elastomeric domain sizes were obtained for the mixing sequence in which all the components forming the ternary nanocomposites were compounded simultaneously. Incorporation sequence of either the organoclay or the impact modifier into the polymeric matrix was varied in the other mixing sequences, and this resulted in poorer distribution of the organoclay platelets and elastomeric domains in the matrix owing to insufficient shear intensity applied on the components in a single extrusion step. Toughness values of the ternary nanocomposites were improved compared with the binary nanocomposites upon addition of the impact modifier into polymer,organoclay combination. It was concluded that the compounding sequence of the components plays a significant role in the dispersion of organoclay and the properties of the nanocomposites, because it directly affects the interaction between the different phases. © 2009 Wiley Periodicals, Inc. Adv Polym Techn 28:155,164, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20158 [source]

    Polyamide 66 binary and ternary nanocomposites: Mechanical and morphological properties

    Miray Mert
    Abstract Polyamide 66 (PA 66)/impact modifier blends and polyamide/organoclay binary and PA 66/organoclay/impact modifier ternary nanocomposites were prepared by the melt-compounding method, and the effects of the mixing sequences on the morphology and mechanical and flow properties were investigated. Lotader AX8840 and Lotader AX8900 were used as impact modifiers. The concentrations of the impact modifiers and the organoclay (Cloisite 25A) were maintained at 2 and 5 wt %, respectively. Both the binary and ternary nanocomposites displayed high tensile strength and Young's modulus values compared to the PA 66/impact modifier blends. Decreases occurred in the strength and stiffness of the binary nanocomposites upon incorporation of the elastomeric materials into the polymeric matrix. In general, the mixing sequence in which all three ingredients were added simultaneously and extruded twice (the All-S mixing sequence) exhibited the most enhanced mechanical properties in comparison with the mixing sequences in which two of the components were extruded in the first extrusion step and the third ingredient was added in the second extrusion step. The mechanical test results were in accordance with the organoclay dispersion. The impact strength was highly affected by the elastomeric domain sizes, interdomain distances, interfacial interactions, and organoclay delamination. The smallest elastomeric domain size was obtained for the All-S mixing sequence, whereas the elastomeric domain sizes of the other mixing sequences were quite close to each other. Drastic variations were not observed between the melt viscosities of the ternary nanocomposites prepared with different mixing sequences. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source]

    Polyamide 6/maleated ethylene,propylene,diene rubber/organoclay composites with or without glycidyl methacrylate as a compatibilizer

    Lingyan Zhang
    Abstract Polyamide 6 (PA6)/maleated ethylene,propylene,diene rubber (EPDM- g -MA)/organoclay (OMMT) composites were melt-compounded through two blending sequences. Glycidyl methacrylate (GMA) was used as a compatibilizer for the ternary composites. The composite prepared through via the premixing of PA6 with OMMT and then further melt blending with EPDM- g -MA exhibited higher impact strength than the composite prepared through the simultaneous blending of all the components. However, satisfactorily balanced mechanical properties could be achieved by the addition of GMA through a one-step blending sequence. The addition of GMA improved the compatibility between PA6 and EPDM- g -MA, and this was due to the reactions between PA6, EPDM- g -MA, and GMA, as proved by Fourier transform infrared analysis and solubility (Molau) testing. In addition, OMMT acted as a compatibilizer for PA6/EPDM- g -MA blends at low contents, but it weakened the interfacial interactions between PA6 and EPDM- g -MA at high contents. Both OMMT and GMA retarded the crystallization of PA6. The complex viscosity, storage modulus, and loss modulus of the composites were obviously affected by the addition of OMMT and GMA. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]

    Hexafluoroisopropanol as size exclusion chromatography mobile phase for Polyamide 6

    Raniero Mendichi
    Abstract The present study deals with the use of hexafluoroisopropanol (HFIP) as size exclusion chromatography (SEC) mobile phase for polyamide 6 (PA6). Contradictory conclusions relating to the use of HFIP as SEC mobile phase for polyamides are found in the literature. By using a multi-detector SEC apparatus equipped with on-line viscometer and multi-angle light scattering we have studied the chromatographic artifacts and the validity of the universal calibration (UC) in HFIP for different PA6 samples (hydrolytic and anionic, monofunctional or bifunctional activator). Appropriate SEC columns and optimized experimental conditions allow most of the chromatographic artifacts to be avoided, even in neat HFIP. The use of a salt in the mobile phase, namely 0.01 M tetraethylammonium nitrate (TEAN), slightly increases the elution volume for both PA6 and PMMA polymers. Under the right conditions, the UC substantially holds for PA6. The validity of the UC is not linked to the presence of TEAN in the mobile phase. With some PA6 samples, namely those anionically synthesized using a bifunctional activator, aggregation becomes a problem and the molar mass in neat HFIP is overestimated. Addition of TEAN prevents any aggregation of the above anionically synthesized PA6. In contrast, the use of a different salt, namely potassium trifluoroacetate, increases the extent of aggregation. [source]

    Unique Orientation Textures Induced by Confined Crystal Growth of Poly(vinylidene fluoride) in Oriented Blends with Polyamide 6

    Akira Kaito
    Abstract Unique orientation textures have been induced by the confined crystal growth of PVDF in drawn films of PVDF/PA6 blends. Oriented films of PVDF/PA6 blends were prepared by uniaxially drawing melt-mixed blends. The drawn films with fixed lengths were heat-treated at 180,°C for 3 minutes to melt the PVDF component, followed by non-isothermal crystallization of PVDF at a cooling rate of 0.5,°C,·,min,1. The crystal orientation was studied by WAXD. When PVDF was melted and recrystallized in the drawn films of the PVDF/PA6,=,50/50 blend at a slow cooling rate, the crystal b- axis of the , -crystalline form of PVDF was oriented in the drawing direction, forming orthogonal orientation textures. SEM showed that stretched domains of PVDF with diameters of 0.2,0.5 µm were dispersed in the PA6 phase in the drawn films of the PVDF/PA6,=,50/50 blend. Spatial confinement of the crystal growth resulted in the alignment of the crystal b- axis along the long axis of the domains, because PVDF is crystallized in thin cylindrical domains. The orientation behavior is different from the oriented crystallization of PVDF/PA11 (Y. Li, A. Kaito, Macromol. Rapid Commun. 2003, 24, 255), in which transcrystallization from the interface causes the a- axis orientation to be in the drawing direction. It is thought that the domain size influenced the mechanism of oriented crystallization and the resultant crystal orientation. [source]

    Structure, Morphology and Properties of a Novel Molecular Composite by In-Situ Blending of Anionic Polyamide 6 with a Polyamide Copolymer Containing Rigid Segments

    Xiaochun Wang
    Abstract 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 , crystal increased slightly with the majority of crystallites being , 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. [source]

    Composite Polyamide 6/Polypyrrole Conductive Nanofibers

    Flavio Granato
    Abstract Conductive Polyamide 6 (PA-6) nanofibers were prepared by making a conductive polypyrrole coating obtained by a polymerization of pyrrole molecules directly on the fiber surface. A solution of PA-6 added with ferric chloride in formic acid has been electrospun and the fibers obtained showed an average diameter of 260 nm with a smooth surface. The fibers have been then exposed to pyrrole vapours and a compact coating of polypyrrole was formed on the fiber surface. The growth of the coating was monitored by measuring the increment of the fiber diameter and by FT-IR spectroscopy. The same technique was used to study the interaction between the ferric chloride and the polyamide chains. The polypyrrole coating on the fibers turned out to be conductive with a pure resistive characteristic and the stability of the conductivity was evaluated in air at room temperature. [source]

    Co-continuous Polyamide 6 (PA6)/Acrylonitrile-Butadiene-Styrene (ABS) Nanocomposites

    Yongjin Li
    Abstract Summary: Polyamide 6 (PA6)/acrylonitrile-butadiene-styrene (ABS) (40/60 w/w) nanocomposites with a novel morphology were prepared by the melt mixing of PA6, ABS and organoclay. The blend nanocomposites had a co-continuous structure, in which both PA6 and styrene-acrylonitrile (SAN) were continuous phases. It was found that the toughening rubber particles were only located in the SAN phase and the strengthening clay platelets were selectively dispersed in the PA6 phase. The co-continuous nanocomposites showed greatly improved mechanical properties over the whole temperature range when compared with the same blend sample without clay. Schematic diagram for the co-continuous ABS/PA6 blend nanocomposite. [source]

    Effect of clay modification on the morphological, mechanical, and thermal properties of polyamide 6/polypropylene/montmorillonite nanocomposites

    POLYMER COMPOSITES, Issue 7 2010
    Polyamide 6/polypropylene (PA6/PP = 70/30 parts) blends containing 4 phr (parts per hundred resin) of organophilic montmorillonite (OMMT) were prepared by melt compounding. The sodium montmorillonite (Na-MMT) was modified using three different types of alkyl ammonium salts, namely dodecylamine, 12-aminolauric acid, and stearylamine. The effect of clay modification on the morphological and mechanical properties of PA6/PP nanocomposites was investigated using x-ray diffraction (XRD), transmission electron microscopy (TEM), tensile, flexural, and impact tests. The thermal properties of PA6/PP nanocomposites were characterized using thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), and heat distortion temperature (HDT). XRD and TEM results indicated the formation of exfoliated structure for the PA6/PP nanocomposites prepared using stearylamine modified montmorillonite. On the other hand, a mixture of intercalated and exfoliated structures was found for the PA6/PP nanocomposites prepared using 12-aminolauric acid and dodecylamine modified montmorillonite. Incorporation of OMMT increased the stiffness but decreased the ductility and toughness of PA6/PP blend. The PA6/PP nanocomposite containing stearylamine modified montmorillonite showed the highest tensile, flexural, and thermal properties among all nanocomposites. This could be attributed to better exfoliated structure in the PA6/PP nanocomposite containing stearylamine modified montmorillonite. The storage modulus and HDT of PA6/PP blend were increased significantly with the incorporation of both Na-MMT and OMMT. The highest value in both storage modulus and HDT was found in the PA6/PP nanocomposite containing stearylamine modified montmorillonite due to its better exfoliated structure. POLYM. COMPOS., 31:1156,1167, 2010. © 2009 Society of Plastics Engineers [source]

    Effect of zirconium dioxide on crystallization and melting behavior of flame sprayed polyamide 1010

    POLYMER COMPOSITES, Issue 4 2008
    Yadong Li
    The crystallization and melting behavior of flame sprayed Polyamide 1010 (PA1010) containing zirconium dioxide (ZrO2) were investigated using differential scanning calorimeter (DSC). ZrO2 has a heterogenous nucleation effect on PA1010, leading to a moderate increase in the crystallization temperature and a decrease in the supercooling temperature. A modified Avrami theory could be successfully used to well describe the early stages of non-isothermal crystallization of PA1010 and its composite coatings. A study of the nucleation activity, which indicated the influence of the filler on the polymer matrix, revealed that the zirconium dioxide nanoparticles had a good nucleation effect on PA1010. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers. [source]

    Synthesis of exfoliated polyamide 6,6/organically modified montmorillonite nanocomposites by in situ interfacial polymerization

    POLYMER COMPOSITES, Issue 6 2007
    M. Tarameshlou
    Polyamide 6,6 (PA 6,6)/organically modified montmorillonite (OMMT) nanocomposites were prepared by a novel method, using direct interfacial polymerization of an aqueous hexamethylene diamine and a nonaqueous adipoyl chloride in dichloromethane solution containing different amounts of OMMT dispersed nanoparticles. The state of dispersion of OMMT in the PA 6,6 matrix was investigated by means of X-ray diffraction, as well as transmission electronic microscopy. The results indicated that the OMMT nanoparticles were dispersed homogeneously and nearly exfoliated in the PA 6,6 matrix. The random arrangement of clay platelets in the PA 6,6 matrix, exfoliation, and intercalation of clays between the PA 6,6 matrix were distinguished. The amount of the incorporated OMMT in the PA 6,6 matrix was determined by means of TGA technique. Furthermore it was found that addition of a small amount of OMMT dramatically improved the thermal stability of PA 6,6. The TGA thermograms of all the synthesized nanocomposite samples showed an interesting unexpected lag in the weight loss at high temperatures, which could be another evidence for formation of fully exfoliated nanocomposites structures, with improved thermal stability. Nucleating effect of the OMMT nanoparticles and their influence on crystallization behavior of PA 6,6 was confirmed by DSC. Finally it is concluded that the in situ interfacial polycondensation is a suitable method for synthesis of nanocomposites with well dispersed structures and enhanced properties. POLYM. COMPOS., 28:733,738, 2007. © 2007 Society of Plastics Engineers [source]

    Compatibilizing effect of ethylene,propylene,diene grafted maleic anhydride terpolymer on the blend of polyamide 66 and thermal liquid crystalline polymer

    POLYMER COMPOSITES, Issue 6 2006
    Qunfeng Yue
    Polyamide 66,thermal liquid crystalline polymer (PA66/TLCP) composites containing 10 wt% TLCP was compatibilized by ethylene,propylene,diene-grafted maleic anhydride terpolymer (MAH- g -EPDM). The blending was performed on a twin-screw extrusion, followed by an injection molding. The rheological, dynamic mechanical analysis (DMA), thermal, mechanical properties, as well as the morphology and FTIR spectra, of the blends were investigated and discussed. Rheological, DMA, and FTIR spectra results showed that MAH- g -EPDM is an effective compatibilizer for PA66/TLCP blends. The mechanical test indicated that the tensile strength, tensile elongation, and the bending strength of the blends were improved with the increase of the content of MAH- g -EPDM, which implied that the blends probably have a great frictional shear force, resulting from strong adhesion at the interface between the matrix and the dispersion phase; while the bending modulus was weakened with the increase of MAH- g -EPDM content, which is attributed to the development of the crystalline phase of PA66 hampered by adding MAH- g -EPDM. POLYM. COMPOS., 27:608,613, 2006. © 2006 Society of Plastics Engineers [source]

    Effect of clay on the morphology of binary blends of polyamide 6 with high density polyethylene and HDPE- graft -acrylic acid

    Zhengping Fang
    Polyamide 6 (PA6)/HDPE/organo-bentonite (Oclay) and PA6/HDPE- grafted -acrylic acid (PEAA)/Oclay nanocomposites were prepared via melt compounding. The influence of Oclay on the morphology of composites was investigated. Scanning electron microscopy results revealed the size of the dispersed HDPE, and PEAA phase decreased with increasing Oclay content. Transmission electron microscopy and X-ray diffraction results revealed that the Oclay was predominately intercalated with some evidence of partial exfoliation. The majority of Oclay platelets were concentrated in the PA6 phase and in the interfacial region between PA6 and HDPE (PEAA). The Oclay platelets played the role of coupling species between the two polymers, increasing the interaction of the two phases in certain extent. These results were proved by FTIR and positron annihilation lifetime spectroscopy. Consequently, apparent emulsifying effect was induced. A schematic mechanism of the apparent compatibilization effect was presented. POLYM. ENG. SCI., 47:551,559, 2007. © 2007 Society of Plastics Engineers. [source]

    Effect of the type of nylon chain-end on the compatibilization of PP/PP-GMA/nylon 6 blends

    Adriana Tedesco
    Abstract Polyamide and polypropylene (PP) are two important classes of commercial polymers; however, their direct mixing leads to incompatible blends with poor properties. Polypropylene functionalized with glycidyl methacrylate (PP-GMA) was used as a compatibilizer in blends of PP and nylon 6, because of the possible reaction of NH2 and COOH groups with the epoxide group of GMA. Two types of nylon 6 with different ratios between NH2 and COOH groups were used. The one with higher concentration of COOH groups was less compatible with PP in a binary blend. When PP-GMA was used as a compatibilizer, a better dispersion of nylon in the PP matrix was obtained together with better mechanical properties for both nylons used in this work. © 2001 Society of Chemical Industry [source]

    Synthesis and characterization of new soluble polyamides from an unsymmetrical diamine bearing a bulky triaryl pyridine pendent group

    Mousa Ghaemy
    Abstract New unsymmetrical diamine monomer containing triaryl pyridine pendent group, 2,4-diaminophenyl [4-(2, 6-diphenyl-4-pyridyl) phenyl]ether, was synthesized via aromatic substitution reaction of 1-chloro-2,4-dinitrobenzene with 4-(2,6-diphenyl-4-pyridyl) phenol, followed by Pd/C-catalyzed hydrazine reduction. Five Polyamides (PA) were prepared by the phosphorylation polycondensation of different dicarboxylic diacids with the diamine. Inherent viscosities of PAs were in the range 0.51,0.59 g/dL indicating formation of medium molecular weight polymers. The weight and number average molecular weights of a PA, (PA-d), determined by GPC were 6944 g/mol and 17,369 g/mol, respectively. PAs exhibited glass-transition temperatures (Tg) in the range 140,235°C. These polymers, essentially amorphous, were soluble in polar aprotic solvents such as DMF, NMP, DMAc, DMSO, pyridine, m -cresol, and THF. The initial decomposition temperatures (Ti) of PAs, determined by TGA in air, were in the range 300,380°C indicating their good thermal stability. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source]

    Polyamides nanocapsules: Modeling and wall thickness estimation

    AICHE JOURNAL, Issue 6 2006
    K. Bouchemal
    Abstract This work provides a better understanding for effective control of the nanocapsules wall thickness. Polyamides based nanocapsules are prepared by interfacial polymerization combined with spontaneous emulsification. A clear guideline of how factors such as monomer concentration, diffusion, interfacial reaction, or water swelling influence the capsule formation is very important to the control of capsule wall structure and release performance. In this goal, the macroscopic planar models of the interfacial polycondensation between diethylenetriamine and sebacoyle chloride are studied experimentally and theoretically. This planar model is developed to examine the kinetics of the reaction and to perform the estimation of parameters thanks to the experiment measurements. The effect of the operating conditions on the wall thickness is also studied. The model is shown to be consistent with the experimental data. Next, the spherical model is deduced from the first one. The results obtained with this model are in accordance with some observations of wall thickness. From this model, the increase of the wall thickness is predicted for several operating conditions. © 2006 American Institute of Chemical Engineers AIChE J, 2006 [source]

    Synthetic polymers containing ,-amino acids: from polyamides to poly(ester amide)s,

    Jordi Puiggalí
    Abstract Polyamides and poly(ester amide)s which contain glycine residues as a comonomer show unique features. In collaboration with Professor M. Goodman we carried out studies on low molecular weight models which allow a structural analysis with atomic detail. In this way, sequential polyamides constituted by glycine and ,-amino acids may adopt new structures characterized by a network of intermolecular hydrogen bonds that are established along three directions at 120°. This peculiar structure is based on the conformational preferences of glycine residues. X-ray and electron microscopy studies on poly(ester amide)s indicate a structure constituted by a stacking of hydrogen bonded sheets. Differences have been found in the shift between consecutive sheets. Copyright © 2005 European Peptide Society and John Wiley & Sons, Ltd. [source]

    Influence of cylinder-on-plate or block-on-ring sliding configurations on friction and wear of pure and filled engineering polymers

    P. Samyn
    Abstract Polyamides, polyesters and polyacetals are often used in line contacts under reciprocating or continuous sliding. These contacts are simulated on cylinder-on-plate (COP) or block-on-ring (BOR) tribotests. Comparative tests for pure, oil-filled and solid lubricated polymers at 100N and 0.3m/s are presented for relative material classification. Differences are discussed according to the sliding geometries. Thermal effects dominate friction and wear behaviour: the polymer glass transition temperature is exceeded in COP tests while the temperature is lower in BOR tests. Thick and brittle films are observed for pure polymers in BOR tests, promoting higher friction. The test configuration is mainly important for evaluation of internal lubricants. The efficiency of oil-lubricated polymers is not demonstrated in COP tests, while solid lubricants are not efficient in BOR tests. Deformation restricts the diffusion of oil lubricants in COP tests while solid lubricants are deposited on the polymer surface rather than being incorporated in the transfer film in BOR tests. Copyright © 2007 John Wiley & Sons, Ltd. [source]

    Unsaturated Polyamides from Bio-Based Z -octadec-9-enedioic Acid

    Francis Pardal
    Abstract A series of polyamides based on Z- octadec-9-enedioic acid, a bio-based unsaturated monomer, and aliphatic-, cycloaliphatic-, or benzylic diamines were synthesized and characterized by 1H and 13C NMR analysis, size exclusion chromatography (SEC), DSC, and dynamic-mechanical analysis (DMA). The high reaction temperature (250,°C) did not lead to the degradation of diacid unit double bonds and unsaturated polyamides were obtained. The aliphatic unsaturated polyamides are semi-crystalline polymers of high molar mass, relatively flexible at room temperature. The cycloaliphatic unsaturated polyamides are semi-crystalline or amorphous, present higher melting and glass transition temperatures and are much more rigid. The aliphatic and aliphatic,aromatic unsaturated polyamides present lower Tg and Tm as compared to their parent saturated polymers. [source]

    Polyamides X.34: A New Class of Polyamides with Long Alkane Segments

    Moritz Ehrenstein
    Abstract A new series of semi-crystalline polyamides (PA), which comprise extended aliphatic segments between the amide moieties and which display an interesting amphiphilic character has been synthesized and characterized. The polymers PA-2.34, PA-4.34, PA-8.34, PA-10.34, and PA-12.34 were prepared by melt-polycondensation of salts of tetratriacontanedioic acid and the respective short-chain diamine. The thermal properties of these polymers were investigated by differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical thermal analysis. The new polyamides exhibit melting temperatures that depend on the length of the diamine and range between 166 (PA-12.34) and 190,°C (PA-2.34). Solid transitions were observed between 38 and 57,°C. The materials displayed a rather limited solubility in common polyamide solvents, but readily dissolved in alkylsulfonic acids. All members of the series formed thermo-reversible gels in the highly polar sulfuric acid and 1,2,3,4-tetrahydronaphthalene, reflecting their interesting amphiphilic character. Young's moduli and tensile strengths of melt-processed, isotropic films of the polyamides investigated were in the range of 0.5,0.7 GPa and 20.30 MPa, respectively, independent of the length of the diamine used. Melting temperatures of polyamides PA-X.34 (x) and 1,2,3,4-tetrahydronaphthalene/PA-X.34 gels (37.5 wt.-% polyamide, determined from the second DSC heating scans) (+). [source]

    Long-Aliphatic-Segment Polyamides: Salt Preparation and Subsequent Anhydrous Polymerization

    Anastasia C. Boussia
    Abstract Long-aliphatic-segment polyamides were prepared based on hexamethylenediamine and ,,, -(CH2)x biosynthetic diacids (x,=,10, 11, 12). The pertinent monomers (salts) were isolated as solids, thoroughly characterized for the first time, and then submitted to an anhydrous melt prepolymerization technique. The obtained prepolymers exhibited in the range of 5 100,11 800,g,·,mol,1, and the molecular weight was further increased by up to 55% through solid-state finishing. The suggested overall polyamidation cycle was conducted at short melt-reaction times, so as to avoid any thermal degradation, and was proved efficient, indicating similar reactants polymerizability independently of the methylene content. [source]

    Reactive Blending of Polyamides with Different Carbonyl Containing Olefin Polymers

    David Sémeril
    Abstract In this paper the blending of polyamides nylon 6 and nylon 12, with a perfectly alternating ethylene/CO copolymer containing 50 mol-% carbonyl groups (polyketone) is investigated in comparison to blends of the same polyamides with polyolefins containing varying degrees of carbonyl group incorporation. These include a poly[ethylene- co -(methyl acrylate)] copolymer containing 1.9 mol-% methyl ester groups and poly[ethylene- co -(ethyl undecylenate)] copolymers with between 0.20 and 1.25 mol-% ester incorporation. Blends were obtained of polyamides and the polyolefins in compositions between 20/80 and 80/20 in solution and in a Brabender mixer. SEM studies together with TGA, DSC and FTIR measurements show excellent compatibilization for both polyketone and poly[ethylene- co -(methyl acrylate)] copolymers with the nylons. The poly[ethylene- co -(ethyl undecylenate)] polymers displayed much less compatibilization although they still performed significantly better compared to pure polyethylene. The difference in compatibilization is discussed with respect to the importance of both the number of interactive groups present in the polyolefin and the steric requirements of hydrogen bond formation. SEM micrograph of the fracture surface of the blend nylon 6/polyethylene 70:30. [source]

    Graph-set and packing analysis of hydrogen-bonded networks in polyamide structures in the Cambridge Structural Database

    W. D. Samuel Motherwell
    The hydrogen-bond networks and crystal packing of 81 unique secondary di- and polyamides in the Cambridge Structural Database are investigated. Graph-set analysis, as implemented in the RPluto program, is used to classify network motifs. These have been rationalized in terms of the relative dispositions of the amide groups. Peptide and retropeptides exhibit significant conformational flexibility, which permits alternative hydrogen-bonding patterns. In peptides, dihedral angles of ,,,,, 105° allow an antiparallel ladder arrangement, containing rings of either the same or alternating sizes. For retropeptides, and diamides with an odd number of CH2 spacers, this conformation leads to a parallel ladder with rings of equal size. If , approaches ,60° and , 180°, ladders adopt a helical twist, and if the conformation is distorted further, a three-dimensional network is usually adopted. Diamides with aromatic or an even number of CH2 spacers generally form either antiparallel ladders or sheets, although some exhibit both polymorphs. Symmetry relationships within and between hydrogen-bonded chains, ladders and sheets in the crystal packing have also been analysed. Polyamides form considerably more complex networks, although many of the structural motifs present in the diamides occur as components of these networks. [source]