High-performance Engineering Polymers Research Articles

High-performance thermoplastic nanocomposites for aerospace applications: A review of synthesis, production, and analysis

Thermoset polymers are cured under natural or synthetic created conditions and retain their solid form when exposed to heat. Unlike thermosets, thermoplastics melt when exposed to heat after production. Thermoplastics are preferred as raw materials because they can be easily shaped after production, have a high shelf life and are recyclable. In this regard, the prominence of high-performance engineering polymers in recent years has led to the preference of alternative polymers to thermosets. High-performance engineering thermoplastics include thermoplastics such as polyphenylene-sulfide (PPS), polyether-ether-ketone (PEEK), polyether-ketone-ketone (PEKK), polyphenylene-ether, polysulfone,polyoxadiazole, polyimide, polyether-amide, polyether-amide-imide, polynaphthalene, and polyamide-imide. These polymers exhibit application potential in aerospace, defense, automotive, marine, energy, and medical sectors. In challenging conditions such as high pressure, temperature, and corrosive environments, they possess high service temperatures, enhanced mechanical and physical properties, preferable chemical resistance as well as out-of-autoclave and rapid processing properties. In this review article, nanomaterial production methods (bottom-up and top-bottom) are mentioned. In the following sections, PPS, PEEK, and PEKK thermoplastics are explained, and carbon- and boron-based nano additives used in constructing nanocomposites are investigated. In the last section, PPS, PEKK, and PEEK polymer nanocomposites are investigated.

Tribological Performance and Enhancing Mechanism of 3D Printed PEEK Coated with In Situ ZIF-8 Nanomaterial.

Polyether ether ketone (PEEK) is esteemed as a high-performance engineering polymer renowned for its exceptional mechanical properties and thermal stability. Nonetheless, the majority of polymer-based lubricating materials fail to meet the contemporary industrial demands for motion components regarding high speed, heavy loading, temperature resistance, and precise control. Utilizing 3D printing technology to design and fabricate intricately structured components, developing high-performance polymer self-lubricating materials becomes imperative to fulfill the stringent operational requirements of motion mechanisms. This study introduces a novel approach employing 3D printing technology to produce PEEK with varying filling densities and conducting in situ synthesis of zeolitic imidazolate framework (ZIF-8) nanomaterials on its surface to enhance PEEK's frictional performance. The research discusses the synthetic methodology, characterization techniques, and tribological performance evaluation of in situ synthesized ZIF-8 nanomaterials on PEEK surfaces. The findings demonstrate a significant enhancement in frictional performance of the composite material under low-load conditions, achieving a minimum wear rate of 4.68 × 10-6 mm3/N·m compared to the non-grafted PEEK material's wear rate of 1.091 × 10-5 mm3/N·m, an approximately 1.3 times improvement. Detailed characterization and analysis of the worn surface of the steel ring unveil the lubrication mechanism of the ZIF-8 nanoparticles, thereby presenting new prospects for the diversified applications of PEEK.

In-situ polymerization of PANI nanocone array on PEN nanofibrous membranes for solar-driven interfacial evaporation

Solar-driven interfacial evaporation (SDIE) holds great potential for desalination, but it also poses challenges to application performance. Herein, a novel polyaniline (PANI) modified polyarylene ether nitrile (PEN) electrospun nanofibrous membranes (PANI@PEN) was developed by introducing PDA and CTAB, which increased the polymerization amount of PANI and controlled its morphology by sequential in-situ polymerization, aiming to enhance its SDIE comprehensive performance. This unique structure can generate multiple diffuse reflections under sunlight, resulting in the highest water evaporation rate of the nanofibrous membrane at 1.822 kg m−2 h−1, while evaporation rate at 1.527 kg m−2 h−1 for a 3.5 wt% sodium chloride solution. Due to the good flexibility of PEN polymer substrate, the obtained membranes can be easily arched, showcasing an interesting ability to collect salt through salt deposition. Meanwhile, PEN also provides a robust skeleton, endowed PANI@PENs with corrosion-resistant, capable of desalination in acidic media, purifying heavy metal ion solutions through evaporation, as well as good mechanical properties for reusability. The study potentially provides a strategy for utilizing dopamine and CTAB loaded on high-performance polymer nanofibrous membranes and the convenient in-situ polymerization to generate advanced photothermal PANI. This strategy paves a way to enable high-performance engineering polymer, PEN, with solar-thermal evaporation capabilities, further opening its potential applications in seawater desalination and industrial wastewater purification.

Development of a Low Cost Extrusion Based 3D Printer for High Performance Engineering Polymers

The development of a low cost 3D printer is presented for high performance polymers by example of a PEI type material. The development steps and technical alternatives opted for during the design process are outlined in two cycles targeting first printing of non-demanding thermoplastics, such as ABS, PLA etc., followed by an upgrade to printing PEI and similar high performance polymers. Subsystems discussed pertain to the frame, CNC axes including feed motors and motion control, the extruder, hot end and nozzle. Of particular interest are modifications concerning the temperature setting and regulation subsystems of the printer work volume and the printing table. Calibration procedures with pitfalls and solutions is discussed and a documented series of finally successful tests for Ultem1010TM is presented.

Dual Nanofillers-Reinforced Noncovalently Cross-Linked Polymeric Composites with Unprecedented Mechanical Strength

Open AccessCCS ChemistryRESEARCH ARTICLES9 Dec 2022Dual Nanofillers-Reinforced Noncovalently Cross-Linked Polymeric Composites with Unprecedented Mechanical Strength Ni An, Youliang Zhu, Xiaohan Wang, Yixuan Li, Junjun Liu, Xu Fang, Zhongyuan Lu, Bai Yang and Junqi Sun Ni An Google Scholar More articles by this author , Youliang Zhu Google Scholar More articles by this author , Xiaohan Wang Google Scholar More articles by this author , Yixuan Li Google Scholar More articles by this author , Junjun Liu Google Scholar More articles by this author , Xu Fang Google Scholar More articles by this author , Zhongyuan Lu Google Scholar More articles by this author , Bai Yang Google Scholar More articles by this author and Junqi Sun Google Scholar More articles by this author https://doi.org/10.31635/ccschem.022.202202496 SectionsSupplemental MaterialAboutPDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareFacebookTwitterLinked InEmail Noncovalently cross-linked polymer materials can reduce materials consumption and alleviate environmental pollution through healing, recycling, and reprocessing. However, it remains a huge challenge to fabricate superstrong noncovalently cross-linked polymer materials with mechanical strength comparable to highperformance engineering polymers. Herein, healable and reprocessable noncovalently cross-linked polymer composites with an unprecedented mechanical strength are fabricated by complexation of polyacrylic acid (PAA), polyvinylpyrrolidone (PVPON) and carbonized polymer dots (CPDs) (denoted as PAA-PVPON-CPDs). The incorporation of 15 wt% CPDs generates PAA-PVPON-CPDs composites with a tensile strength of ~158 MPa and Young’s modulus of ~8.2 GPa. Serving as nanofillers, the CPDs can establish strong interactions with polymers in PAA-PVPON composites. The CPDs and the in situ-formed PAA-PVPON nanoparticles work in concert to significantly strengthen the PAA-PVPON-CPDs composites to an unprecedented strength. The PAAPVPON-CPDs composites exhibit excellent impact resistance and damage tolerance because of the high mechanical strength of the composites and the energy dissipation mechanism of the CPDs and PAA-PVPON nanoparticles. Moreover, the fractured PAA-PVPON-CPDs composites can be healed to restore their original mechanical strength. Download figure Download PowerPoint Previous articleNext article FiguresReferencesRelatedDetails Issue AssignmentVolume 0Issue jaPage: 1-27Supporting Information Copyright & Permissions© 2022 Chinese Chemical Society Downloaded 53 times PDF downloadLoading ...

Effect of olive pomace particles content on mode I and mode II delamination fracture of S‐glass fiber reinforced composites

AbstractThis work aims to investigate the effect of micro‐sized olive pomace (OP) particle incorporation on the mode I and mode II delamination fractures of glass fiber reinforced polymer composites. In this way, it is possible to recycle the natural OP materials and benefit from the development of high performance engineering polymer matrix composites in industrial applications as well as producing low cost composite. For this purpose, six different OP weight ratios (0%, 0.5%, 1%, 5%, 10%, and 15%) were used for modification of matrix resin of composite samples. Double‐cantilever beam, end‐notched flexure tests were conducted according to ASTM standards for evaluation of mode I and mode II fracture delamination toughness properties of the OP filled composites. Scanning electron microscopy photos were taken from the fractured test samples after the mode I and II interlaminar fracture tests to characterize their morphological nature. The results showed that the mode I and mode II inter‐laminar fracture toughness values reached the highest value at OP content of 5 wt% with enhancement of 13.8% and 60.4%, respectively.

Synthesis and characterization of alternating copolyoxamide with high heat resistance and excellent crystallization property

A novel alternating copolyoxamide of poly (decamethylene oxamide-alt-hexamethylene oxamide) (PA102-alt-62) was synthesized by oxalate-terminated bisester–bisoxalamide (262-diester) and decamethylene diamine via solution/solid-state polycondensation (SSP). The alternating structure was confirmed by solution 1H NMR and 13C NMR spectra. The thermal properties were addressed by DSC and TGA and the results revealed that PA102-alt-62 possessed quite high Tm (284 °C) and ΔHf (94 J g−1) as well as excellent thermal stability (T5 = 415 °C). The high crystallinity (38%) as determined by WAXD and the extremely short t1/2 at 250 °C (10 s) calculated from analysis of isothermal crystallization demonstrated that PA102-alt-62 had outstanding crystallization properties. As to the modulus of PA102-alt-62, it was almost twice as the random counterpart at room temperature and still as high as 1 GPa at 140 °C as revealed by DMA test. All the results suggested that PA102-alt-62 was a high-performance engineering polymer.

Heat of Decomposition and Fire Retardant Behavior of Polyimide-Graphene Nanocomposites

Polyimide is a high-performance engineering polymer with outstanding thermomechanical properties. Because of its inherent fire-retardant properties, polyimide nanocomposite is an excellent material for packaging electronic devices, and it is an attractive electrode material for batteries and supercapacitors. The fire-retardant behavior of polyimide can be remarkably improved when polyimide is reinforced with multilayered graphene sheets. Differential scanning calorimetry and thermogravimetric analysis were used to study the heat of decomposition and gravimetric decomposition rate, respectively, of polyimide-graphene nanocomposites. Polyimide/graphene nanocomposites containing 10, 20, 30, 40, and 50 wt.% of multilayered graphene sheets were heated at a rate of 10 and 30 °C/min in air and in nitrogen atmosphere, respectively. The rate of mass loss was found to remarkably decrease by up to 198% for nanocomposites containing 50 wt.% of graphene. The enthalpy change resulting from the decomposition of the imide ring was found to decrease by 1166% in nitrogen atmosphere, indicating the outstanding heat-shielding properties of multilayered graphene sheets due to their high thermal conductivity. Graphene sheets are believed to form a continuous carbonaceous char layer that protects the imide ring against decomposition, hence decreasing initial mass loss. The enthalpy changes due to combustion, obtained from differential scanning calorimetry, were used to calculate the theoretical heat release rates, a major parameter in the determination of flammability of polymers. The heat release rate decreased by 62% for composites containing 10 wt.% of graphene compared to the neat polyimide matrix. Polyimide has a relatively lower heat of combustion as compared with graphene. However, graphene significantly decreases the mass loss rates of polyimide. The combined interaction of graphene and polyimide led to an overall decrease in the heat release rate. It is noted that both mass loss rate and heat of combustion are important factors that contribute to the rate of heat released.

Structure-property and bioimaging application of the difunctional polyarylene ether nitrile with AIEE feature and carboxyl group

A series of AIEE and carboxyl difunctional polyarylene ether nitrile (PEN) were synthesized via stepwise polymerization. Their structure-property and bioimaging application were studied. The synthesized PEN exhibited excellent thermal resistance with thermal decomposition temperature beyond 380 °C and glass transition temperature over 192 °C. Incorporation of AIEgen imparted PEN with a higher quantum yield (36%), and emission peak redshift from weak blue to bright cyan region under solid state. The soluble polymer also can be processed into flexible films by casting method with good mechanical property and strong fluorescent emitting. Under the synergistic action of difunctional segments, PEN was endowed with the assembled fluorescent polymeric nanoparticles (FPNs) though the coordination effect between metal ions and carboxyl group with much higher emission efficiently. Finally, based on the well biocompatible and hydrophilia of difunctional PEN, the obtained FPNs revealed the cellular bioimaging application. The current work lays the foundation for PEN perform as a high-performance engineering polymer with fluorescent perform in the development of optical applications.

Evaluation of elastomeric heat shielding materials as insulators for solid propellant rocket motors: A short review

AbstractThis review addresses a comparison, based on the literature, among nitrile rubber (NBR), ethylene-propylene-diene-monomer rubber (EPDM), and polyurethane (PU) elastomeric heat shielding materials (EHSM). Currently, these are utilized for the insulation of rocket engines to prevent catastrophic breakdown if combustion gases from propellant reaches the motor case. The objective of this review is to evaluate the performance of PU–EHSM, NBR–EHSM, and EPDM–EHSM as insulators, the latter being the current state of the art in solid rocket motor (SRM) internal insulation. From our review, PU–EHSM emerged as an alternative to EPDM–EHSM because of their easier processability and compatibility with composite propellant. With the appropriate reinforcement and concentration in the rubber, they could replace EPDM in certain applications such as rocket motors filled with composite propellant. A critical assessment and future trends are included. Rubber composites novelties as EHSM employs specialty fillers, such as carbon nanotubes, graphene, polyhedral oligosilsesquioxane (POSS), nanofibers, nanoparticles, and high-performance engineering polymers such as polyetherimide and polyphosphazenes.

Synthesis of a Regioregular Series of Poly(aryl ether carbonates) and Their Glass Transition Temperatures.

Bisphenol A polycarbonate (BPA-PC) is a remarkable high-performance engineering polymer, although it is susceptible to photo-Fries and hydrolytic degradation. New poly(aryl ether carbonates) were synthesized to address these limitations by replacing the chain backbone carbonate ester functionality with aryl ether functionality. The monomers for these new polymers were synthesized by a variation of the Ullmann condensation accelerated by 2,2,6,6-tetramethylheptane-3,5-dione and promoted by Cs2CO3 and 1-methyl-2-pyrrolidinone under mild conditions. Four such bisphenol A-based diarylether monomers containing different mass ratios of carbonate ester groups were prepared and polymerized with phosgene gas to give novel poly(aryl ether carbonates). Polymers were named as di-o-BPA-PC 9′, tri-o-BPA-PC 11′, tetra-o-BPA-PC 13′, and penta-o-BPA-PC 15′ where di-, tri-, tetra-, and penta- reflect the number of diphenylisopropylidene units in each of the respective polymers. The molecular weights of the resulting four poly(aryl ether carbonates) were measured by gel permeation chromatography. Differential scanning calorimetry was used to measure glass transition temperature (Tg). The polymers exhibited weight-average molecular weights up to 4.09 × 105 g/mol and Tg in the range of 136 to 149 °C with no melting temperature peak, indicative of their amorphous character. The new polymers formed transparent and flexible films by solution casting from chloroform solution.

Parametric Identification of Carbon Nanotube Nanocomposites Constitutive Response

Hysteresis due to stick-slip energy dissipation in carbon nanotube (CNT) nanocomposites is experimentally observed, measured, and identified through a one-dimensional (1D) phenomenological model obtained via reduction of a three-dimensional (3D) mesoscale model. The proposed model is shown to describe the nanocomposite hysteretic response, which features the transition from the purely elastic to the post-stick-slip behavior characterized by the interfacial frictional sliding motion between the polymer chains and the CNTs. Parametric analyses shed light onto the physical meaning of each model parameter and the influence on the material response. The model parameters are determined by fitting the experimentally acquired force–displacement curves of CNT/polymer nanocomposites using a differential evolution algorithm. Nanocomposite beam-like samples made of a high performance engineering polymer and high-aspect-ratio CNTs are fabricated and tested in a bending mode at increasing deflection amplitudes. The entire time histories of the restoring force are fitted by the model through a unique set of parameters. The parameter identification is carried out for nanocomposites with various CNT weight fractions, so as to highlight the model capability to identify a wide variety of nanocomposite hysteretic behaviors through a fine tuning of its constitutive parameters. By exploiting the proposed model, a nanostructured material design and its optimization are made possible toward the exploitation of these promising materials for engineering applications.

Hydrogen ion induced ultralow wear of PEEK under extreme load

As a high-performance engineering polymer, poly(ether ether ketone) (PEEK) is a perfect candidate material for applications under extreme working conditions. However, its high wear rate greatly shortens its service life. In this study, ultralow friction and wear between PEEK and silicon nitride (Si3N4) under extreme-load conditions (with a mean contact pressure above 100 MPa) are found in acid lubricating solutions. Both friction and wear decrease sharply with decreasing pH. At pH = 1, the friction coefficient decreases by an order of magnitude and the wear rate of the PEEK decreases by two orders of magnitude compared to the results with water lubrication. These reductions in friction and wear occur for different speed, load, and surface roughness conditions. The underlying mechanism can be attributed to the formation of hydrogen-ion-induced electrical double layers on the surfaces of PEEK and Si3N4. The combined effect of the resulting repulsive force, electro-viscosity, and low shear strength of the water layer dramatically reduces both friction and wear.

Reaction: Benign by Design Demands Innovation

Prof. Long joined the Department of Chemistry in 1999 after holding positions at Eastman Kodak and Eastman Chemical, and he currently serves as the director of the Macromolecules Innovation Institute at Virginia Tech. Recent recognitions include an AAAS fellowship, ACS fellowship, ACS PMSE Cooperative Research Award, ACS POLY Mark Scholar Award, and the 2015 Virginia Outstanding Scientist award. His interdisciplinary research program focuses on structure, property, processing, and performance relationships of tailored macromolecules. Current interests include materials for additive manufacturing, photo-reactive polymers, block and segmented copolymers, polymer packaging, ion-containing polymers, adhesive science, and high-performance engineering polymers.

Tribological Performance of Polyamide-Imide Seal Ring Under Seawater Lubrication

High-performance engineering polymers are potential candidate materials for mechanical seals, especially in corrosive environments and environments where substantial shock and vibration loads are present. This study addresses the friction and wear performances of polyamide-imide (PAI) sliding against tungsten carbide (WC) in seawater for seal applications. The experimental setup consists of two nominally flat rings rotating against each other to simulate the contact in mechanical seals. Three types of experiments were performed, i.e., measurement of friction and wear in a series of 8-h tests, measurement of the friction coefficient as a function of speed and load and measurement of PV (pressure times velocity) limit. Test results show that at lightly loaded conditions WC/PAI seal rings in seawater can reach hydrodynamic lubrication with ultra-low friction coefficient and wear rate.

Improvement of the Toughness and Crack Propagation Resistance Properties of Poly(Phenylene Sulfide)

Poly(phenylene sulfide) (PPS) is a high-performance thermoplastic engineering polymer, which exhibits outstanding properties such as electrical insulation, dimensional and thermal stability, chemical resistance, etc. In addition to this, PPS has a high degree of crystallinity and it exhibits good physical properties at elevated temperatures. Owing to these properties, PPS is widely used in electrical and electronic components, automobile industry and mechanical applications. These outstanding properties of PPS can be attributed to its chemical structure, composed of phenyl groups linked by a sulfur atom, which gives rigidity to the chain. On the other hand, the brittleness with low elongation strain, toughness and crack propagation resistance also restricts its further applications. Several methods are used to overcome these undesirable properties of PPS. Blending of PPS with other polymers is one of these methods. In this study, Ethylene-Acrylic Ester-Glycidyl Methacrylate terpolymer (Lotader®-AX8900) was used to improve the toughness and crack propagation resistance properties of PPS. For this purpose, PPS/Lotader (0, 2, 5, 10 wt.% Lotader) blends were prepared at various compositions. The blends were manufactured using laboratory scale twin screw extruder and injection molding machine. Mechanical properties of blends were investigated by using tensile test method. In addition to this, crack propagation and toughness of samples were investigated by using essential work of fracture (EWF) method. As a result of this study, it was found that Lotader addition significantly increases the toughness and crack propagation resistance of PPS.

Microstructural Properties of Particle-Reinforced Polytetrafluoroethylene Composite Bearings After Wear

High-performance engineering polymers that ensure the desired properties of journal bearings and give good wear results are investigated. We determine the microstructural properties of polymer-based particle-reinforced polytetrafluoroethylene composite bearings by analyzing the optical and SEM surface wear images.

Extraordinary toughening and strengthening effect in polymer nanocomposites using lignin-based fillers synthesized by ATRP

Understanding of the governing parameters that control the interaction of bio-sourced fillers with synthetic polymer materials is a long-standing challenge for their exploitation as a platform for material engineering. For the case of graft-lignin embedded in poly (methyl methacrylate) (PMMA) it is demonstrated that tethering of polymeric chains with appropriate chain length to the surface of lignin-fillers dramatically increases the mechanical properties of PMMA/lignin composites, suggesting the PMMA grafts significantly enhanced filler–matrix interactions. Most metrics were maximized at 1% loading, with a 3-fold increase in yield stress, a 4-fold increase in tensile strength, and a 7-fold increase in toughness, with a combination of properties that compare favorably to high-performance engineering polymers and polymer nanocomposites based on inorganic nanoparticles. The versatility of the surface-initiated controlled radical polymerization used for polymer graft modification suggests that the approach should be broadly applicable to a wide range of commodity and engineering polymers.

To Investigate the Wear Mechanism on Cryogenic Treatment of PTFE-Mica Filled Composite Coatings in Cookware

Poly-tetrafluoroethylene (PTFE) is a high performance engineering polymer generally used as a coating material. PTFE shows poor wear resistance, thus in order to improve the wear resistance of PTFE, cryogenic treatment (CT) has proved to be the most effective technique. The improvement in wear performance of PTFE on CT at −185 °C for 12 h has been conclusively established whereas, its effectivity on PTFE-mica composite coating is not yet studied. Thus in the present investigation the suitable parameters of CT for PTFE composite coating are established. In addition to this, the wear behaviour and mechanism of different types of PTFE composite coatings, popularly used in non-stick cookware is also studied in a comparative manner as before and after CT. The wear performance of the composite is found to be enhanced.

Machining behaviour of three high-performance engineering plastics

Polymeric materials have been widely used to replace traditional metallic materials due to their high specific elastic properties. Even though polymeric materials can be produced as near net shapes, machining is still required to make the assembling of the final products. The selection of tool and cutting conditions is very important to machine plastics because of the high ductility and low melting point of the materials. In this study, the machining behaviour of high-performance engineering polymers, such as ultra-high-molecular-weight polyethylene, polyoxymethylene and polytetrafluoroethylene, has been investigated using a full-factorial design (design of experiment). The effect of the factors such as feed speed, spindle speed and drill point angle was identified for each of the response variables (circularity error, surface roughness (Ra) and thrust force (Ff)). The drilling mechanism was substantially affected by the physical and mechanical properties of the polymers. Different cutting set-up conditions were able to optimize the responses. The polytetrafluoroethylene exhibited better results, achieving lower circularity error, surface roughness and thrust force. In the opposite manner, the ultra-high-molecular-weight polyethylene exhibited a rough topography at low feed rate and spindle speed levels.