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Although polymer-based self-lubricating materials have rapidly developed recently, intelligent lubricating materials with self-adaptable lubrication with external conditions changing are highly demanded, especially for harsh conditions. Herein, a shape memory epoxy resin based on the biphenyl units (BPEP) with tunable tribological behavior was systematically studied. X-ray diffraction (XRD), field emission scanning electron microscope (SEM), laser confocal three-dimensional profiler, and optical microscope were applied to analyze the friction and wear mechanism. Due to the presence of the specific biphenyl structural units, which could be performed a switching phase between crystalline and amorphous, that allows the self-assembly of the polymer chain under π–π interaction. As a result, the improving mechanical properties enable the BPEP to perform outstanding self-lubricating in a wide temperature range, and the friction coefficient (COF) can be tuned in a wide range of 0.10~0.175 by adjusting the temperature. The shape memory effect of the polymer refers to modulus changing and heat conversion during the shape morphing, and a thermal tunable tribological was observed based on the physicochemical properties varying of polymer with temperature changing. The shape memory effect of BPEPs drives the wear self-compensation so that a low wear rate (6.94 × 10−5 mm3 N−1 m−1) at 110 °C was obtained. The superb lubricating properties of this BPEP could broaden the application scope of shape memory polymers in the field of intelligent lubricating materials, and it is expected to guide future studies on the thermal regulating of tribological behavior. [ABSTRACT FROM AUTHOR]

Shape memory epoxy resin (SMEP) with tailorable properties has gained wide attention. Herein, a series of photocured diphenyl epoxy with excellent shape memory effects, based on the epoxy monomer diglycidyl ether of biphenyl (DGEBP) and M‐xylylenediamine (MXDA), is fabricated. Fourier transform infrared spectrometer (FTIR) is used to verify the mix‐curing process. Differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), polarized light microscope (POM), and X‐ray diffraction (XRD) are applied to analyze the microstructure of the film. The molar ratio of the raw material and the post‐heating could tune the crosslinking density, which allows the prepared epoxy resin to present a tailorable shape memory effect. Besides, this epoxy resin exhibits an excellent triple‐shape memory effect due to the wide transition temperature. It is worth of noting that post‐heating induced the self‐assembly of biphenyl unit of the lamellar structure due to π–π interactions that causes an adjustable shape memory effect. This work offers a novel SMEP with potential application in the thermal history trace field. [ABSTRACT FROM AUTHOR]

A series of micro hollow glass beads (HGB) filled castor oil-based polyurethane/epoxy resin graft interpenetrating polymer network (IPN) composites were prepared. The tensile and impact strengths, impact fractured surfaces, damping properties and thermal stability of the IPN composites were studied systematically in terms of composition. Results revealed that the addition of HGB into polyurethane/epoxy IPN can significantly improve not only the tensile strength but also the impact strength. The tensile strength was increased by 61% and at the same time the impact strength was increased by 25% when the HGB content was 1.5%. The damping properties were better than the composition of 0.5% or 2% HGB content when the HGB content was 1% or 1.5%. The thermal decomposition temperature was also slightly improved by the incorporation of HGB. It is suggested that the HGB reinforced polyurethane/epoxy resin IPN composites could be used as structural damping materials. [ABSTRACT FROM AUTHOR]

In this article, a series of novel semi‐interpenetrating polymer networks (s‐IPNs) based on linear polyimide (PI) and crosslinked epoxy (EP) were firstly prepared aiming at controlling violent vibration and noise originating from operation of the machine. The damping, thermal, and mechanical performances of s‐IPNs films were systematically investigated in terms of the structure of polyimide (the molar ratios of diamines) and the component ratios of PI/EP. The results indicate that PI/EP s‐IPNs films exhibit prominent damping properties, and the effective damping temperature range can reach up to 58.8 °C when molar ratio of diamines is 1:3 within PI and component ratio of PI/EP is 70:30. Meanwhile, all the PI/EP s‐IPNs films show good thermal stability compared to cured EP and certain mechanical behaviors due to the formation of semi‐interpenetrated structure. Meaningfully, the prepared novel PI/EP s‐IPNs will be used as effective damping materials and have a potential application in damping fields. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48032. [ABSTRACT FROM AUTHOR]

With the development of energy-saving industries, the tribology and thermal management of composites were increasingly urgent. Here, we explored the dual-network graphene/epoxy composites with enhanced tribological and thermal management. The 3D graphene was prepared using calcium ions as the crosslinker and melamine foam as template. Subsequently, the reinforced concrete-like composites were obtained by dipping in silica-filled epoxy. The research results show that the thermal conductivity of the composites was enhanced by 1015.52% compared to the silica-filled epoxy. Simultaneously, the friction coefficient of the composites was reduced to 0.29 with the wear rate be reduced to 0.19 × 10−5 mm3/N∙m under the condition of 5 N and 2 cm/s. This dual-network model provides a new strategy for the development of solid lubricating materials with excellent thermal management. • The 3D graphene was prepared by template method, using Ca2+ as the crosslinking agent. • The dual-network graphene/epoxy composites were obtained by dipping method. • The thermal conductivity was up to 1.54 W/m∙k with the estimated GMF mass fraction 3.10 wt% • The friction coefficient was reduced to 0.31, with the wear rate was reduced by 97.25%. • Confirmed the key role of thermal conductivity in improving the tribological properties of materials. [ABSTRACT FROM AUTHOR]

Shape memory polymer with high transition temperature (T r) is highly demanded in many fields. A cyanate ester (CE) based shape memory polymer with tunable T r and excellent mechanical property was prepared by using CE, carboxy-terminated liquid nitrile rubber (CTBN) and epoxy resin (E51 or GE36) in this work. The rheological behavior and fourier transformation infrared spectrogram results indicate the addition of CTBN containing of carboxylate could accelerate the triazine forming and reduce the curing temperature. Adding CTBN and epoxy resin to CE resulted in the formed network with reduced triazine density that the toughness was significantly improved, the elongation at break can reach up to 40%. The T r , mechanically property could be tuned in a larger range by adjusting the ratio between CE, CTBN and epoxy resin. The shape memory cyanate ester (SMCE) presented an excellent shape memory effect even a triple shape memory effect. This work provides a promise shape memory material for broad applications. [Display omitted] • A cyanate ester (CE) based shape memory polymer with tunable T g and excellent mechanical property was prepared. • Adding carboxy-terminated liquid nitrile rubber and epoxy resin to CE resulted in the toughness significantly improving. • The shape memory cyanate ester (SMCE) presented an excellent shape memory even a triple shape memory effect. [ABSTRACT FROM AUTHOR]

• Hyperbranched polyurethane was applied through grafting epoxy resin to obtain interpenetrating polymer networks. • Crosslinking network points help enhancing thermal and mechanical properties. • All interpenetrating polymer networks express excellent shape memory effect. In this article, a type of hyperbranched polyurethane (HBPU) with triazine structure was successfully synthesized. Afterwards, HBPU was applied through grafting epoxy resin (EP) to fabricate the interpenetrating polymer networks (IPNs) with different ratio of HBPU/EP. The structure of HBPU prepolymer and the formation of the HBPU/EP IPNs were characterized and confirmed by Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared (FTIR) spectroscopy, and the nanoscale phase separation in IPNs composite was analyzed by Atomic Force Microscope (AFM). Besides, the thermal and mechanical results indicated that the IPNs structure enables the material with high strength and thermal stability. Shape memory cycles test demonstrated that the HBPU/EP INPs possess an excellent shape memory performance, and the best shape fixity and recovery were presented by IPNs composite with 20 wt% HBPU. [ABSTRACT FROM AUTHOR]

The poor interfacial compatibility between functional fillers and matrix greatly restricts development of polymer composites. Therefore, in the present paper, carbon fibers (CFs) were modified by biomimetic polydopamine (PDA) and amino silane (KH550) to improve interfacial bonding strength with epoxy (EP) substrate. The grafting of PDA and KH550 was divided into "PDA", "PDA-KH550" and "(PDA + KH550)" methods for regulating interfacial compatibility and exploring the reaction mechanism. Improved interfacial strength was beneficial to transfer stress from the matrix to fillers. Consequently, mechanical properties of modified CF/EP were obviously superior to those of unmodified EP/CF. Besides, wear resistance of EP/CF-(PDA + KH550) had an increase of 76%, 67%, 60% and 49% compared to that of EP, CF/EP, CF-PDA/EP and EP/CF-PDA-KH550. Image 1 • PDA and KH550 were used to regulate interfacial compatibility of CF and EP. • The different reaction mechanisms of PDA and KH550 were explored. • The tribological mechanism of modified CF/EP were systematically analyzed. • "CF-(PDA + KH550)" method significantly improved simultaneously the mechanical properties and wear resistance. [ABSTRACT FROM AUTHOR]