High-performance Polymeric Materials Research Articles

The Durability and Performance Test methods of the New Type of Pavement Filling Material - An Holistic Review

Airport pavement joint weaknesses are one of the important factors that affect airport performance and threaten flight safety. The traditional pavement caulking materials are mainly asphalt-based materials of heating construction type, which are prone to aging, loss of adhesion and other shortcomings in natural environment. Based on the shortcomings of traditional pavement caulking materials, this paper introduces the research and application status of new type of filling caulking materials represented by high-performance elastic polymer materials, with emphasis on its durability, performance testing methods. Finally, it summarizes the existing problems and prospects of the new type of pavement filling caulking materials.

Significantly Improved Breakdown Strength and Energy Density in Polymer Composites with High Filler Loading by Constructing Isoelectronic Traps

High-performance dielectric polymer materials consisting of ZnS:O nanoparticles (ZSO NPs) with isoelectronic traps and polyvinylidene fluoride (PVDF) were prepared by a solution-casting method. Com...

Realizing simultaneous improvements in mechanical strength, flame retardancy and smoke suppression of ABS nanocomposites from multifunctional graphene

Acrylonitrile-butadiene-styrene (ABS), as one of the most widely used engineering plastics, suffers from the problem of serious flammability and low mechanical strength. To address such an intractable challenge, herein, we report the design of a graphene-based multifunctional additive (Sb-Mo/Br-rGO) via the bromination followed by precipitating antimony molybdenum. The surface functionalization enables Sb-Mo/Br-rGO to homogeneously disperse within the ABS matrix through facile melt-blending. The incorporation of 5 wt% Sb-Mo/Br-rGO leads to a 31% increase in tensile strength and 73% increase in elastic modulus relative to the ABS bulk. In addition to significant enhancement in thermal stability, the inclusion of 5 wt% Sb-Mo/Br-rGO significantly delays the time to ignition of ABS by 12 s, and noticeably reduces the peak heat release rate (PHRR) and total smoke production (TSP) by 45% and 54%, respectively. Such improved performance portfolio is primarily because the mechanical reinforcing and thermal barrier effect of graphene nanosheets, the flame retardant effect of bromine/antimony, and the smoke suppression action of antimony molybdenum. This work provides an innovative methodology for the design of multifunctional additives to create high-performance polymeric materials with high strength and low flammability, thus contributing to improving the quality of life.

Trends in Power Module Packaging Technologies and Expectations for Polymer Materials

The evolution of the organic insulated power module and technology of high thermal conductivity and high heat resistance of the key material, which is the Thermally Conductive Electrically Insulating Layer (TCIL), have been reported. TCIL is a polymer / ceramic composite material filled with thermally conductive filler of ceramics in thermosetting resin. Due to the evolution of TCIL and utilization of bonding function that is characteristic of thermosetting resin, the heat dissipation performances have been greatly improved and the downsizing and higher power density of organic insulated module were achieved. Innovations on high performance polymer materials are expected to further improve the performance of power modules in the future.

High-Performance Polymeric Materials through Hydrogen-Bond Cross-Linking.

It has always been critical to develop high-performance polymeric materials with exceptional mechanical strength and toughness, thermal stability, and even healable properties for meeting performance requirements in industry. Conventional chemical cross-linking leads to enhanced mechanical strength and thermostability at the expense of extensibility due to mutually exclusive mechanisms. Such major challenges have recently been addressed by using noncovalent cross-linking of reversible multiple hydrogen-bonds (H-bonds) that widely exist in biological materials, such as silk and muscle. Recent decades have witnessed the development of many tailor-made high-performance H-bond cross-linked polymeric materials. Here, recent advances in H-bond cross-linking strategies are reviewed for creating high-performance polymeric materials. H-bond cross-linking of polymers can be realized via i) self-association of interchain multiple H-bonding interactions or specific H-bond cross-linking motifs, such as 2-ureido-4-pyrimidone units with self-complementary quadruple H-bonds and ii) addition of external cross-linkers, including small molecules, nanoparticles, and polymer aggregates. The resultant cross-linked polymers normally exhibit tunable high strength, large extensibility, improved thermostability, and healable capability. Such performance portfolios enable these advanced polymers to find many significant cutting-edge applications. Major challenges facing existing H-bond cross-linking strategies are discussed, and some promising approaches for designing H-bond cross-linked polymeric materials in the future are also proposed.

Towards a Stable and High-Performance Hindered Phenol/Polymer-Based Damping Material Through Structure Optimization and Damping Mechanism Revelation.

Although hindered phenol/polymer-based hybrid damping materials, with excellent damping performance, attract more and more attention, the poor stability of hindered phenol limits the application of such promising materials. To solve this problem, a linear hindered phenol with amorphous state and low polarity was synthesized and related polyurethane-based hybrid materials were prepared in this study. The structure and state of the hindered phenol were confirmed by nuclear magnetic resonance spectrum, Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The existence of intermolecular hydrogen bonds (HBs) between hindered phenol and polyurethane was confirmed by FT-IR, and the amorphous state of the hybrids was confirmed by XRD. Moreover, by a combination of molecular dynamics simulation and dynamic mechanical analysis, the relationship between the structure optimization of the hindered phenol and the high damping performance of the hybrids was quantitatively revealed. By constructing the synthetic hindered phenol, the intramolecular HBs between hindered phenols were restricted, while the strength and concentration of the intermolecular HBs increased by increasing the amount of hindered phenol. Thus, intermolecular interactions were enhanced, which lead to the compact chain packing of polyurethane, extended chain packing of hindered phenol, and good dispersion of hindered phenol in polyurethane. Therefore, the stability of the hindered phenol and the damping properties of the hybrids were both improved. The experiment results are expected to provide some useful information for the design and fabrication of high-performance polymeric damping materials.

Flame retardant eugenol-based thiol-ene polymer networks with high mechanical strength and transparency

Exploring renewable bio-based polymer materials with intrinsic flame retardancy and high mechanical strength will greatly increase the potential to meet fire safety and practicability requirements. In this study, a hexa-substituted cyclophosphazene monomer (HEP) is synthesized from abundant and renewable eugenol and then copolymerized with multi-thiol monomers to establish HEP-SH polymer networks by thiol-ene photopolymerization. Four HEP-SH polymer networks (HEP-TEGDT, HEP-TTMP, HEP-PETMP, HEP-TEMPIC) were prepared by varying the number of thiol groups or the backbone of thiol monomers. Among these polymer networks, HEP-PETMP and HEP-TEMPIC networks exhibit excellent flame retardancy (LOI > 27 vol.%, achieved UL 94 V-0 rating). The combustion parameters and flame retardant mechanism are further studied by cone calorimetry and combined scanning electron microscopy/energy-dispersive spectroscopy (SEM-EDS), which confirm the intumescent flame retardancy of HEP-SH networks is simultaneously affected by the contents of phosphorus and nitrogen element, as well as the structural features of the polymer network. In addition, the HEP-TEMPIC and HEP-PETMP networks also exhibit high mechanical strength and transparency. These eugenol-based thiol-ene polymer networks open a new pathway to develop sustainable high-performance flame retardant bio-based polymer materials for practical application.

Phase structure and electrical and mechanical properties of PLLA/ionic conductive polyether blends prepared by melt mixing

Poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) is known as an ionic conductive polymer and exhibits ionic conductivity when it forms a complex with a metal salt. In this study, poly(L-lactic acid) (PLLA)/POEGMA/poly(methyl methacrylate) (PMMA) blends were manufactured to develop high-performance polymer materials that exhibit high mechanical moduli (>1 GPa) and ionic conductivities in the semiconductive region (1.0 × 10 −9–1.0 × 10−7 cm−1) at room temperature. In addition, crystallized blends were prepared by annealing the amorphous blends and were subsequently evaluated. By mixing PLLA and the compound consisting of POEGMA and PMMA using a two-roll mill, a blend with a maximum ionic conductivity of ~1.1 × 10–7 S cm−1 was obtained. The scanning electron microscopy results indicated that the ionic conductive phases were finely dispersed within the blends. By comparing the storage modulus values of the crystallized blends to those of amorphous blends, we found that the crystallized blends were harder at approximately the glass transition temperature of PLLA. We prepared ionic conductive compound (ICC) by solution casting and the in situ polymerization of poly(ethylene glycol) methyl ether methacrylate (OEGMA) in the presence of PMMA and a cross-linking agent. Then, ionic conductive polymer blends was obtained by melt-mixing ICC and poly(L-lactic acid) (PLLA). We studied the relationship between phase structure and physical properties such as electrical and mechanical properties of the blends.

A novel core-shell epoxy high performance composite: Self-lubricating, heat-resistant and self-repairing

In order to obtain a comprehensive high-performance polymer material that satisfies the application requirements under complex working conditions such as thermal field, friction or even damage, in this work, the core-shell structure of Silica sol modified Diphenylmethane diisocyanate (MDI) @Epoxy resin (EP) / F atoms-contained-amine (F-A) hybrid was successfully synthesized. After the obtained microsphere material was added as reinforcing filler to the EP substrate, we performed mechanical, tribological, self-repairing and thermal properties characterization. In particular, the resulting composite has a coefficient of friction of only about 0.13 and a thermal conductivity better than 0.2 W / (m K). Here, we provide a new mechanism for efficient self-healing of materials damaged under friction conditions, and impart lubricity and unprecedented heat resistance to the material.

Studies on thermo mechanical and surface properties of polysulfone/poly(ether imide ester) blends

Polyimides are high performance polymeric materials with excellent physical, thermal and mechanical properties, but its application is limited due to low processability and poor solubility. In order to improve processability and solubility without sacrificing thermal stability, flexible linkages such as ether and ester units were incorporated into the polyimide backbone. Poly (ether imide ester)s were prepared by high temperature solution polycondensation reaction. The blends of polysulfone (PSf) and poly (ether imide ester) were prepared by solution casting method. The effect of blend ratio on morphological, hydrophilic, mechanical and thermal properties of the resultant blends were evaluated. Thermal properties of the blends were analyzed using thermo gravimetric analysis and differential scanning calorimetry. The contact angle measurements was carried out to study the influence of poly (ether imide ester) in corporation on the wettability of the of PSf matrix. Various surface parameters such as total surface free energy, interfacial free energy, work of adhesion, spreading coefficient and Girifalco-Good’s interaction parameter were calculated from the measured contact angle values.

Tribology of natural Poly-Ether-Ether-Ketone (PEEK) under transmission oil lubrication

Abstract High performance polymeric materials such as poly-ether-ether-ketone (PEEK) are increasingly being used for challenging tribological applications in order to replace metal parts in vehicle engines and transmissions. The tribology of natural PEEK, under oil-lubricated conditions, was studied for different metal counterbody finishes. Two different finishing processes were selected for this study: turning and polishing. The test system used was a tri-pin on disc, with pins made of PEEK and counterbodies made of steel, and then dipped in ATF Dexron VI oil. The conclusion was that the wear rate generated by turning was about seven times as high as the wear rate generated by polishing. The friction coefficient displayed a direct correlation with the lubrication regime, and the level of counterbody roughness. On average, the friction coefficient on the hydrodynamic regime for polishing was more than 3 times lower than the friction coefficient in the boundary regime for turning.

Natural fiber reinforced polymer composites: history, types, advantages, and applications

Nowadays, the use of natural fiber reinforced polymer-based composites is gradually increasing day by day for their many advantages for civil engineering construction applications. Due to their many advantages for polymer-based composite materials are widely used in civil construction, automobiles, aerospace, and many others. Natural fibers such as jute, kenaf, pineapple, sugarcane, hemp, oil palm, flax, and leaf, etc. are cheap, environmentally friendly, renewable, completely and partially biodegradable which can be utilized to obtain new high-performance polymer materials. These composites are having satisfactory mechanical properties (i.e. tensile properties, flexural stress-strain behavior, fracture toughness, and fracture strength) which make them more attractive than other composites. Due to easy availability and renewability, natural fibers can be used as an alternative of synthetic fibers as a reinforcing agent. The aim of this paper is to review different natural fibers reinforced based polymer composites with mechanical characterization, applications, also shows the opportunities, challenges and future demand of natural composite material towards civil applications.

Sodium alginate-templated synthesis of g-C3N4/carbon spheres/Cu ternary nanohybrids for fire safety application

Constructing novel graphic carbon nitride (g-C3N4)-based nanohybrids via a facile method for high-performance polymeric materials which exhibit enhanced fire safety properties are highly desirable. Here, the g-C3N4/carbon sphere/Cu (denoted as CSACS-C) nanohybrid was prepared by metal ions-induced gel reaction using sodium alginate as a green template, and thereafter introduced into thermoplastic polyurethane (TPU) matrix to prepare nanocomposites. Microstructure analyses indicated the successful synthesis of the ternary nanohybrid, where both the g-C3N4 nanosheets and Cu nanoparticles were well-dispersed in the carbon material. Moreover, the ternary nanohybrid showed good distribution in TPU matrices, and exhibited strong interfacial adhesion with the polymeric host. It is worth noting that addition of these nanohybrids led to significantly improved fire safety. Particularly, remarkably reduced pyrolysis gaseous products generation and peak of heat release rate were achieved for TPU/CSACS-C system. This enhanced fire safety was due to the interpretations that the SACS and g-C3N4 nanosheets retarded the heat and mass propagation, while the incorporation of Cu nanoparticles induced earlier thermal decomposition into more char residues and less pyrolysis gaseous products. The work provides a new, simple strategy to prepare nanohybrids for polymeric materials with enhanced fire safety.

Synthesis and Polymerization of Naphthoxazines Containing Furan Groups: An Approach to Novel Biobased and Flame-Resistant Thermosets

Naphthoxazines are a class of compounds with potential application in obtaining high-performance polymeric materials. Such application of these compounds, however, is still scarcely explored in the literature. Combined with the search for new high-performance materials, the development of biobased polymers has gained a lot of attention. In this sense, the inclusion of furan groups in polymers has been explored as a strategy that combines the search for high-performance materials with the search for the development of biobased materials. In this work, novel naphthoxazine monomers containing furan groups were synthetized. The syntheses were carried out in a single step, without the use of solvents and catalysts, obtaining the products in satisfactory yields and high purity. The naphthoxazines had their chemical structures completely characterized by FTIR, 1H NMR, and 13C NMR techniques. The thermal analyses (DSC and TGA) showed that all naphthoxazines exhibit exothermic typical polymerization events, making these compounds suitable for obtention of poly(naphthoxazines) resins, but suffer significant mass losses at temperatures below the onset polymerization temperature. In this way, a catalyst (1 mol% MgCl2) was used in order to allow the polymerization of the compounds before the mass loss events. The FTIR analysis showed strong evidences of the formation of poly(naphthoxazines), and TGA analyses showed that the resins have high thermal stability, with high flame resistance and self-extinguishing properties (LOI > 28), which makes these compounds attractive in the development of biobased and high-performance materials.

Reinforcing and toughening isotactic polypropylene through shear-induced crystallization and β-nucleating agent induced crystallization

In this article, iPP with β-nucleating agent was molded by sequential co-injection molding (SCIM), in which skin and core melt were injected into the mold cavity one after the other. The microstructure and mechanical properties of samples were investigated by polarized optical microscope (POM), wide angle X-ray diffraction (WAXD) and mechanical property test. Results show that plastic parts molded by SCIM have double shear layers due to twice shear induced by filling flow of skin and core melt. In the shear layers especially the layer at the overlap of skin and core material, shear promoted the formation of highly oriented structures (shish-kebabs) but inhibited the produce of β-form. In core layer of skin material and core layer of core material, β crystals are predominant. The combination of oriented structures (shish-kebabs) and β crystals endow iPP with high strength and toughness. This work demonstrates a new approach to achieve high-performance polymer materials based on general plastics by manipulation strategy for morphology and structure.

Improvement of heat resistance and mechanical properties of epoxy resin with nano-Cu-Ni supported RGO

ABSTRACTThis study reports the synthesis and characterization of epoxy resin/redox graphene/nano-copper-nickel (EP/RGO/Cu-Ni) composites. The RGO/Cu-Ni was characterized by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Using dynamic thermodynamic analysis (DMA), the glass transition temperature (Tg) of the modified epoxy resin was increased by 21°C compared to EP. The addition of 1.3 wt% RGO/Cu-Ni to the epoxy matrix resulted in an increase of 79.6% and 161.3% respectively in the tensile strength and impact strength of the new material. Finally, the excellent mechanical properties of EP/RGO/Cu-Ni nanocomposites contribute to the research and development of new high-performance polymer materials.

Optically transparent, organosoluble poly(ether-amide)s bearing triptycene unit; synthesis and characterization

Aromatic polyamides are famous high performance polymeric materials for their excellent thermal, mechanical, electrical properties, which now a days became a dominant platform for modern polymer chemistry area. Triptycene unit like structures in polymer directly affects the physiochemical properties of polymer, thus polyamides especially with triptycene unit in their backbone with aryl ether linkage imparts combination of properties such as better solubility, melts processing characteristics, and better thermal stability in contrast with those of polymers without an aryl-ether linkageNew triptycene-containing bis(ether amine), 1,4-bis(4-aminophenoxy), 2, 3-benzotriptycene (4a) was synthesized from nucleophilic displacement reactions of P-fluoronitrobenzene with 1,4-dihydroxytriptycene, followed by reduction, and elucidated by FTIR, 1 H, 13 C NMR spectroscopy and HRMS. A series of new polyamides containing pendant triptycene group and flexibilizing ether linkages was synthesized by polycondensation of diamine with commercially available aromatic diacischlorides viz., terephthalylchloride (TPC), isophthalylchloride (IPC) and varying molar mixture of TPC and IPC accordingly. Synthesized Poly(ether-amide)s were found soluble in common organic solvents such as chloroform, dichloromethane, tetrahydrofuran, DMF, DMAc, DMSO also could be cast into excellent transperent thin films. Inherent viscosities of polyamides were in the range 0.44–0.57 dL/g. Polyamides exhibited initial decomposition temperature (Ti), glass transition temperatures (Tg) and temperature at 10% wt loss (t10), which was determined by TGA were noted in the range 212 °C–305 °C, 295 °C –309 °C and 587 °C–631 °C respectively with 24%–54% char yeild at 900 °C under nitrogen atmosphere, indicating its better thermal stability and moderate glass transition temperature.

Grain coarsening on the free surface and in the thickness direction of a sphere-forming triblock copolymer film

Controlling a block copolymer “grain”, in which the microdomains are regularly ordered in a single lattice, is important for developing high-performance polymeric materials. This is because the grains, which are several micrometers in size, can directly affect the properties of the materials. In this regard, we focused on grain coarsening on the free surface and in the thickness direction of a sphere-forming triblock copolymer film. We evaluated the grain size on the free surface using atomic force microscopy combined with image processing, and in the thickness direction, we used small-angle X-ray scattering edge-view measurements. It was found that the grain growth in the direction parallel to the free surface was very slow in the early stage of thermal annealing. Then, the grain growth shifted to a rapid growth mechanism with a power-law relationship (grain size ~tα, with α = 0.7) after ~30 min. Based on the value of the growth exponent α, the grain growth mechanism is considered to fall between the random and deterministic processes. In contrast, for the thickness direction, a much larger value (α = 1.72) was obtained. For such a large α value, it is impossible to consider the growth mechanism of the grain within the conventional to framework of the growth of domains and droplets. Therefore, our results may require a new framework to explain the behavior of the grain growth in the spherical microdomain system. Another notable finding is that the thickness of the oriented layer near the free surface or near the surface in contact with the substrate can be as thick as 9.5 µm, which is substantially larger than the reported values of the propagation distance of surface-induced orientation of microdomains in block copolymers. Based on the results of the current study, it is speculated that grain growth serves as a propagator for the regular ordering of spherical microdomains and the orientation of the lattice.

High-performance recyclable cross-linked polyurethane with orthogonal dynamic bonds: The molecular design, microstructures, and macroscopic properties

Polyurethane materials (PUs) have been widely used in industry and daily life due to the versatile chemistry. However, despite the rapid advance in synthetic chemistry, it still remains a significant challenge for the facile fabrication of PUs with a single cross-linked network embedded with excellent mechanical properties and recyclability. Herein, in this study, we proposed a simple strategy to fabricate a high-performance recyclable cross-linked PU and revealed the relationship between microscopic structure and macroscopic properties. The UPy (2-ureido-4-[1H]-pyrimidione) motifs were incorporated into the backbone chains of PUs, where the quadruple hydrogen bonding interactions between UPy dimers can significantly enhance the mechanical strength and toughness. Furthermore, a single small molecular Diels-Alder adduct was utilized as the chemical crosslinker, rendering the final cross-linked PUs healable and recyclable. The thermal reversibility of the Diels-Alder reaction was well verified by DSC and solid-state NMR spectroscopy. Notably, it was found that the incorporation of UPy motifs could enhance the strain-induced crystallization (SIC), leading to a large stress at break. The structural and dynamic changes induced by SIC were quantitatively addressed by proton multiple-quantum NMR spectroscopy and SAXS experiments, where SIC further imposed restrictions on the mobility of surrounding polymer chains in the soft domain and led to the change of microphase separated nanostructures. Overall, a simple strategy is proposed here for the facile fabrication of high performance recyclable PUs, and the detailed investigation here on the structure-property relationship may further provide insights into developing high performance polymeric materials.

Bio-derived aliphatic hyperbranched polyurethane nanocomposites with inherent self healing tendency and surface hydrophobicity: Towards creating high performance smart materials

Smart materials with high performance are useful for multi-dimensional utilities. In this context, bio-resource derived aliphatic hyperbranched polyurethane nanocomposites (HPU/Si-GO) were fabricated in situ with different wt% of the 3-aminopropyltriethoxysilane-modified graphene oxide sheets (Si-GO). The nanocomposites were characterized by FT-IR, Raman, PXRD, EDX, SEM and TEM analyses. Significant enhancements of mechanical properties like tensile strength (∼247%), elongation at break (∼206%) and toughness (∼339%) were observed upon incorporation of very low amount (up to 2 wt%) of Si-GO in HPU matrix. The nanocomposites exhibited excellent self healing ability under microwave (within 50–60 s at 450 W) and sunlight (within 4–6 min under 106 lx) exposure with high efficiency (up to 100%). The surfaces of the nanocomposites also displayed inherent hydrophobicity (water contact angles up to 105°) without any additional surface modification. Hence, development of such high performance polymeric materials with inherent smart features augurs well for versatile applications including self healing and self cleaning materials.