High-performance Polyamides Research Articles

High-performance Thermoplastic-based Magnetic Composites

Magnetic polymer-based composites combine the cost-effectiveness, low density, and manufacturing flexibility of conventional polymers with the unique characteristics of magnetic powders/fillers to form multi-functional magneto polymeric composites that offer superior properties to conventional materials. At higher temperatures, magnetic properties change significantly and the particles within the magnetic powders experience sporadic motion due to the heat which causes misalignment of the magnetic domains, leading to a decrease in magnetism. Due to these adverse temperature effects, high-performance polymers such as polyetheretherketone (PEEK), polyetherimide (PEI), high-performance polyamides (HPPA), or other high-temperature thermoplastics have been considered suitable matrix for the magnetic fillers, thereby creating a much wider usage for magneto polymeric composite in applications that requires higher temperature (typically above 175°C). Thus, this review discusses the fabrication processes-injection molding, fused filament fabrication; magnetic performance, and applications of high-performance thermoplastic-based magnetic composites that can be viable for stringent engineering devices such as sensors, actuators, motors, and generators.

NXTamid-L as a substitute for Nylon 12 and 11

The NXTamid-L family of specialty engineered nylons are claimed to be unique in the performance they offer, and to be quite different from polyamide grades that might be more commonly seen in different applications, such as Nylon 6 or Nylon 66. These specialty high performance polyamides most commonly refer to Nylon 12, Nylon 11, and Nylon 1010. They reportedly are more flexible, have lower moisture absorption, more robust chemical resistance, and other special features that should make them unique for high performance applications. Nylon 11 and Nylon 12 are the most common of these nylons, and unfortunately can present some limitations on applications, including availability and price. To help address these needs, NYCOA announced a new family of specialty nylons to consider as substitutes to Nylon 12 and 11: NXTamid-L.

Boosting electrochromic properties of polyamides through altering the structure bonded to triarylamine groups by xanthene

To obtain a high-performance material with large optical contrast, fast response, stable redox reversibility and easy processability simultaneously, a novel amine monomer, N1, N1'-(spiro(fluorene-9,9′-xanthene)-2,7-diyl)-bis(N1-(4-methoxyphenyl) benzene-1,4-diamine) (SFXMOPb-NH2) was designed and prepared by inserting xanthene group core into two electron-rich triarylamine (TAA) systems. Then, SFXMOPb-NH2 was polycondensed with various carboxylic acids to obtain three high-performance polyamides (PAs), namely SFXMOPb-OA, SFXMOPb-CA, and SFXMOPb-6F, respectively, in which the SFXMOPb-OA possesses excellent properties with good solubility and thermal stability, long cycle stability (cycle times up to 20,000 s and 2000 switching cycles), high coloring efficiency (CE, up to 463 cm2 C−1), and large optical contrast (ΔT, up to 62%). Obvious color transformation from red to blue is obtained in an electrochromic device (ECD). These PAs also reveal memristors properties. It demonstrates that introducing twisted structure and ringlike ether into PAs could pave the way for design and preparation of molecules for fabrication of high-performance EC devices and memristors.

Click Step-Growth Polymerization and E/Z Stereochemistry Using Nucleophilic Thiol-yne/-ene Reactions: Applying Old Concepts for Practical Sustainable (Bio)Materials.

ConspectusPolymer sustainability is synonymous with “bioderived polymers” and the zeitgeist of “using renewable feedstocks”. However, this sentiment does not adequately encompass the requirements of sustainability in polymers. In addition to recycling considerations and mechanical performance, following green chemistry principles also needs to be maximized to improve the sustainability of polymer synthesis. The synthetic cost (i.e., maximizing atom economy, reducing chemical hazards, and lowering energy requirements) of producing polymers should be viewed as equally important to the monomer source (biomass vs petrol platform chemicals). Therefore, combining the use of renewable feedstocks with efficient syntheses and green chemistry principles is imperative to delivering truly sustainable polymers. The high efficiency, atom economy, and single reaction trajectories that define click chemistry reactions position them as ideal chemical approaches to synthesize polymers in a sustainable manner while simultaneously expanding the structural scope of accessible polymers from sustainably sourced chemicals.Click step-growth polymerization using the thiol–yne Michael addition, a reaction first reported over a century ago, has emerged as an extremely mild and atom-efficient pathway to yield high-performance polymers with controllable E/Z stereochemistry along the polymer backbone. Building on studies of aromatic thiol–yne polymers, around 10 years ago our group began investigating the thiol–yne reaction for the stereocontrolled synthesis of alkene-containing aliphatic polyesters. Our early studies established a convenient path to high-molecular-weight (>100 kDa) E-rich or Z-rich step-growth polymers by judiciously changing the catalyst and/or reaction solvent. This method has since been adapted to synthesize fast-degrading polyesters, high-performance polyamides, and resilient hydrogel biomaterials. Across several systems, we have observed dramatic differences in material properties among polymers with different alkene stereochemistry.We have also explored the analogous thiol–ene Michael reaction to create high-performance poly(ester-urethanes) with precise E/Z stereochemistry. In contrast to the stereoselective thiol–yne polymerization, here the use of monomers with predefined E/Z (geometric) isomerism (arising from either alkenes or the planar rigidity of ring units) affords polymers with total control over stereochemistry. This advancement has enabled the synthesis of tough, degradable materials that are derived from sustainable monomer feedstocks. Employing isomers of sugar-derived isohexides, bicyclic rigid-rings possessing geometric isomerism, led to degradable polymers with fundamentally opposing mechanical behavior (i.e., plastic vs elastic) simply by adjusting the stereochemistry of the isohexide.In this Account, we feature our investigation of thiol–yne/–ene click step-growth polymers and efforts to establish structure–property relationships toward degradable materials with practical mechanical performance in the context of sustainable polymers and/or biomaterials. We have paid attention to installing and controlling geometric isomerism by using these click reactions, an overarching objective of our work in this research area. The exquisite control of geometric isomerism that is possible within polymer backbones, as enabled by convenient click chemistry reactions, showcases a powerful approach to creating multipurpose degradable polymers.

Enhanced ductility in high performance polyamides due to strain-induced phase transitions

Copolymerizing poly(hexamethylene terephthalamide-co-isophthalamide) (PA6TI) with 40 wt% polyamide 66 (PA66) results in only minor decreases in modulus and yield stress owing to isomorphous substitution of PA6TI units by PA66 units in the PA6TI α phase, so that crystallinity is maintained in the resulting PA6TI-66 terpolymer. However, the ductility also significantly increases. This is attributed to a deformation-induced transformation of the PA6TI α phase to a disordered form of the PA66 α phase, where PA6TI units constitute defects and the chains adopt extended conformations. This phase is argued to be favored in initially amorphous PA66-rich regions and hence stabilizes interlamellar micro-necks that develop during yielding. By contrast, segregation of isophthaloyl units to the amorphous regions in PA6TI hinders strain-induced crystallization, leading to failure at significantly lower strains. Brittleness may therefore be a generic problem when comonomers are used to facilitate processing, but one that may be overcome through proper microstructural control.

High-performance polyamides with engineered disorder

Introducing molecular scale defects into semiaromatic polyamides by high-temperature melt compounding with aliphatic polyamides provides a simple means of tailoring the balance of microstructural order and disorder in these materials and achieving unusual property profiles.

Synthesis and identification of new thermostable polyamides containing xanthene units with antibacterial properties and relevant composite grafted with modified GO nanoparticles

Two series of new diamine monomers containing ether linkages, polar trifluoromethyl (-CF3), and xanthene segments were prepared. In addition, relevant high-performance polyamides (PAs) were synthesized through condensation polymerization with applying diverse aliphatic and aromatic dicarboxylic acids. The structure of compounds were characterized by Fourier transform infrared (FT-IR), proton nuclear magnetic resonance (1H NMR), and elemental analysis. The inherent viscosities values of the polymers were from 0.48 dL/g to 0.67 dL/g. The PAs indicated the glass transition temperatures (Tg), and 10% weight loss temperatures recorded within the range of 187–244 °C and 395–497 °C in N2 atmosphere, respectively. Polyamides showed a well antibacterial activity, with respect to the presence of xanthene segments in their structure. The polymeric nanocomposite was prepared through a combination of one of the synthesized polyamides with modified graphene oxide nanoparticles (m-GO NPs). The formation of potent chemical linkage across (m-GO) NPs and polymer chains caused photoluminescence intensity to enhance, thermal stability, and antibacterial properties of the nanocomposite than pure polyamide. The study of chromium ions adsorption from aqueous solutions was also performed at 25 °C and pH 7–8.

Structural, Optical and Thermal Characterization of Wholly Aromatic Poly(ether amide)s Synthesized by Phosphorylation‐Based Condensation Polymerization

Abstract[1]To attain high performance polyamides with good thermal properties and enhanced processability, in this study, a series of wholly aromatic poly(ether amides) (PEAs) with different meta‐ and para‐phenylene linkage ratios was synthesized by phosphorylation‐based polycondensation reaction of terephthalic acid (TPA) and/or isophthalic acid (IPA) with 3,4′‐oxydianiline (ODA) in NMP/CaCl2 solvent system. The synthesized PEA homopolymers and copolymers exhibited good solubility in organic polar solvents, such as NMP, DMAc and DMSO. The intrinsic viscosity of the synthesized PEAs in NMP solvent was measured to be in the range of 0.48‐0.97 dl/g. The 1H NMR analyses confirmed that the output compositions of PEA copolymers were quite consistent with the feed compositions. The photographic digital images and UV‐visible spectra showed that solution‐casted PEA films were optically light brown and transparent owing to their amorphous and nonlinear chain structures. The DSC data revealed that the glass transition temperatures of PEAs are in the range of 242–310 °C, depending on the relative contents of meta‐ and para‐phenylene linkages. All PEA films were characterized to be thermally stable up to ∼400 °C and to have high char residues above 63 % at 800 °C in nitrogen atmosphere.

Biobased chiral semi-crystalline or amorphous high-performance polyamides and their scalable stereoselective synthesis

The use of renewable feedstock is one of the twelve key principles of sustainable chemistry. Unfortunately, bio-based compounds often suffer from high production cost and low performance. To fully tap the potential of natural compounds it is important to utilize their functionalities that could make them superior compared to fossil-based resources. Here we show the conversion of (+)-3-carene, a by-product of the cellulose industry into ε-lactams from which polyamides. The lactams are selectively prepared in two diastereomeric configurations, leading to semi-crystalline or amorphous, transparent polymers that can compete with the thermal properties of commercial high-performance polyamides. Copolyamides with caprolactam and laurolactam exhibit an increased glass transition and amorphicity compared to the homopolyamides, potentially broadening the scope of standard polyamides. A four-step one-vessel monomer synthesis, applying chemo-enzymatic catalysis for the initial oxidation step, is established. The great potential of the polyamides is outlined.

Investigation and characterization of ultrasonically welded GF/PA6T composites

High-performance polyamides (HPPA) matrix composite meets the demanding requirement of automotive thermal management applications as a replacement to conventional metals. Effective joining of such composites are still a challenge and a better understanding of material performance upon joining are needed. This research study investigates the behavior of glass filled semi-crystalline and partially aromatic polyamide composite upon ultrasonic plastic welding. Welding process parameters were experimentally realized for a quality weld in shear type joint configuration. A weld strength of 3.1 kN was achieved. Material performance, thermal transition, degradation temperature, mass loss and morphology near welding zone were evaluated by advanced characterization techniques. A decrease in glass transition temperature (Tg) and change in material crystallinity were observed. The morphology of welded interface reveals minimum void formation. Negligible amount of weight loss was observed after welding with a degradation temperature much higher than material melting point, suitable for high temperature applications.

Polyamidation of a diamine-phenol compound in ionic liquid: preparation and properties of polyamides/epoxide-functionalized γ-Al2O3 composites

This work reports selective polyamidation of a diamine-phenol compound (3) in an ionic liquid (IL) and preparation of transparent composites from the obtained high performance polyamides (PA)s and modified γ-Al2O3 nanoparticles (mγNAl). The PAs were prepared selectively from polycondensation of compound 3 with several dicarboxylic acids in the mixture of (IL)/triphenylphophite(TPP). The fluorescent PAs (λem = 500 nm) exhibited glass transition (Tg) and 10 % weight loss temperatures (T10%) in the range of 188–325 °C and 447–511 °C, respectively. The structurally intercalated composites (NCPA)s were prepared from PAs and epoxide-functionalized γ-Al2O3 (mγNAl) via solution blending process. The strong chemical bonding between mγNAl and PA chains contributed to the enhanced thermal and mechanical properties of the composites. Also, the photoluminescence intensity increased with increasing mγNAl content. The PAs and composites were also tested for their extraction capability for environmentally deleterious metal ions from aqueous solutions either individually or in the mixture.

Influence of ionic liquid on selective polycondensation of a new diamine-bisphenol: Synthesis and properties of polyamides and their composites with modified nanosilica

This work reports that imidazolium-based ionic liquids (ILs) are very efficient solvents and catalysts for the selective synthesis of novel high performance polyamides (PAs) from a new diamine-bisphenol. Direct polycondensation of the diamine-bisphenol was carried out with various dicarboxylic acids by using mixture of: (1) triphenylphosphite (TPP)/N-methylpyrolidone (NMP)/pyridine (Py)/LiCl; and (2) IL/TPP. The PAs were obtained in no more than 2.5 h at 110 °C, which is considerably shorter than the conventional direct polycondensation, with mass-average molar mass (Mw) up to 61,000 g mol−1, glass transition temperatures (Tg) up to 325 °C and 10% weight loss temperatures (T10%) up to 511 °C (in N2) and 456 °C (in air). Nanocomposites of these PAs with modified nanosilica (mNS) showed that strong chemical bonding between inorganic particles and the polymer matrix contributed to the enhanced thermal and mechanical properties. The photoluminescence intensity of the PAs increased and the spectra red shifted with increasing mNS content. The PAs and nanocomposites were tested for their extraction capability of metal ions such as Cr3+, Co2+, Zn2+, Pb2+, Cd2+, Hg2+ and Fe3+ from aqueous solutions either individually or in the mixture.

Synthesis of high performance polyamides utilizing copper-catalyzed amidation of a dibromoarene with different diamides

A series of diphenylquinoxaline-containing polyamides were prepared from the condensation polymerization of 2,3-bis (4-bromophenyl) quinoxaline (DBQ) with various primary and secondary diamides via copper-catalyzed amidation reaction. The polyamides were characterized with FTIR, NMR, GPC, differential scanning calorimeter, and thermo gravimetric analysis, and their solubility and viscosity were measured. The polyamides synthesized here are amorphous and showed relatively good solubility in polar aprotic solvents and demonstrate the ability to form brownish hard films by solvent casting; their inherent viscosities ranged from 49 to 55 mL/g. The average molecular weights of polyamides were in the range of Mw = 11,950–5592 g/mol (MWD = 1.21–1.87). These polyamides had relatively high thermal stability with Tg values up to 276°C, 10% weight loss temperatures (T10%) in the range of 364–476°C, and char yields at 600°C in N2 up to 72%. They also exhibit emission in the solid state and in dilute (0.2 g/dL) DMAc solution at 425–484 nm with photoluminescence quantum (ϕf) yields in the range of 14–23%. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

EMS – Der führende Spezialist für Hochleistungspolyamide

This short review introduces EMS-Chemie as a leading producer of high-performance polyamides. The history of polyamides is described as well as their innovative development and modification for customized applications. Bild 2. Die Geschichte der EMS-CHEMIE AG.

More Crash Safety from High-Performance Polyamides and Optimized Simulation Methods

More Crash Safety from High-Performance Polyamides and Optimized Simulation Methods

High Performance Polyamides based on s-Triazine Ring: Synthesis and Characterization

High-performance polymers based on aromatic rings are desirable not only because of the high primary bond strengths, but also because their rigid (stiff) polymer chains offer increased resistance to deformation and thermal softening. The choice of s-triazine nucleus is based on its high thermal stability derived from its molecular symmetry and aromaticity. It is well known that s-triazine is heat resistant. Modification of monomer structures by introduction of aromatic pendent groups or heterocyclic rings into the polymer backbone provides good solubility and thermal stability. A new set of polyamides with —CO—NH— groups were synthesized by the Yamazaki’s phosphorylation reaction 2-(morpholino)-4,6-bis (6-napthoxy-2-carboxy)-s-triazine with various aromatic diamines. The polyamides had inherent viscosities in the range 0.549—0.685 dL g-1 in dimethylformamide at room temperature (30 °C) and density 1.135—1.208 g cm - 3 . All the polyamides showed good thermal stability and most of them were readily soluble at room temperature in polar solvents such as N,N-dimethylacetamide, 1-methyl-2-pyrrolidone and dimethylformamide. Polyamides were synthesized successfully with the favourable properties of higher thermal stability along-with good processibility.

High performance polyamides

Especially for heavy-duty applications such as air intake manifolds and valve and engine covers, high performance polyamides have now become available that will last significantly longer than conventional resins. Due to a new combination of stabilizing additives, they can now achieve lifetimes of 3,000 hours at 150°C.

High-Performance Directional Metallopolyamides. I. Synthesis and Thermal Analysis

High-performance polyamides containing the 4,4′-disubstituted-2,2′-bipyridyl moiety were synthesized by phosphorylation polycondensation from 2,2′-bipyridyl-4,4′-dicarboxylic acid and a series of primary aromatic diamines with triphenylphosphite and pyridine as the agents to facilitate condensation. Polyamides exhibiting improved solubility in organic solvents and strong acids, melting transitions at low temperatures, and good thermal properties were prepared by introducing bulking methyl and fluoro groups and flexible ether and propyl linkages and by using monomers with reduced symmetry. Solutions of the polyamides with rigid main chains (III, IV, V, VI, and VIII) showed birefringence (colorful spherulites) at concentrations of 5, 10, and 15% (w/v) polymer/solvent. The chelation of ruthenium(II) ions resulted in the preparation of directional metallopolyamide systems based on the geometrically favorable tris(2,2′-bipyridyl)ruthenium(II) complex. The three-dimensional polyamides, which absorbed at a λ max of 476 mm and emitted at a λ max of 620 nm, exhibited a high thermal stability and improved solubility, making them suitable candidates for compressive strength studies and cyclic voltammetry studies as part of an effort to address the corrosion of graphite fiber-reinforced composites.