Showing papers by "Ming Qiu Zhang published in 2013"
TL;DR: In this paper, a mini-review outlines recent developments in establishing intrinsic self-healing approaches of the materials through inter-macromolecular reactions towards strength recovery for structural application.
134 citations
TL;DR: In this article, a Covalently bonded stiff polyurethane capable of autonomous intrinsic self-healing was synthesized by introducing a specially designed alkoxyamine unit and a soft segment with sub-ambient Tg and high crystallinity into the main chain.
120 citations
TL;DR: In this article, a thermally molded self-healing thermoplastic polymer containing a multilayer microcapsule-type microreactor was proposed, which consists of an isolated monomer and catalyst system.
Abstract: Here in this work we propose a thermally molded self-healing thermoplastic polymer containing a multilayer microcapsule-type microreactor. The latter consists of an isolated monomer and catalyst system. As the first proof-of-concept composites, commercial plastics polystyrene (PS) filled with glycidyl methacrylate (GMA)-loaded microreactors are reported. The specially designed structure of the microreactors enables them to be robust enough to survive the thermal processing already widely used in the plastics industry, like melt mixing under shear and compression molding. Upon damage of the composites and microreactors, the GMA monomer is released to the cracks and its atom transfer radical polymerization is triggered when it passes by the catalyst layer. The polymerized GMA serves as a macromolecular adhesive, which not only fills up the interstitial gap of the cracks but also is anchored to the sub-surface of the matrix forming mechanical interlocking, offering satisfactory healing efficiency at room temperature. By changing the species of healing monomer, catalyst and wall substances, the microreactors can meet the versatile requirements of different polymers, so that the approach is provided with broad applicability.
52 citations
TL;DR: In this paper, a multilayered microcapsule is proposed and prepared for use in self-healing polymers, where reactants for atom transfer radical polymerization (ATRP) are separately introduced into different places of the micro-capsule to construct a latent ATRP reactor.
49 citations
TL;DR: In this article, a comparison between the bio-foams with intrinsic flame retardancy on a molecular level and those containing inflaming retardant fillers revealed that the latter have acquired rather poor mechanical properties and hence are obviously inferior to the former in practical applications where a loadbearing capability is required.
Abstract: Acrylated epoxidized soybean oil was chemically grafted with difunctional flame retardants carrying phosphorus, double bonds or biphenyl groups, and then copolymerized with styrene to produce bio-foams with high mechanical properties and intrinsic flame resistance. Owing to the introduction of rigid comonomer, phosphorus, additional double bonds or biphenyl side groups, the bio-foams showed compressive strength similar to that of conventional unsaturated polyester foam, antiflaming capability and biodegradability as well. More importantly, the modified flame retardant partially took the role of styrene, leading to a lower fraction of petroleum based substance in the bio-foams without the expense of foam strength, and improved biodegradability. The comparison between the bio-foams with intrinsic flame retardancy on a molecular level and those containing inflaming retardant fillers revealed that the latter have acquired rather poor mechanical properties and hence are obviously inferior to the former in practical applications where a load-bearing capability is required.
36 citations
TL;DR: In this paper, a light-emitting conjugated polymer (PCFOz) was used to initiate excitation and propagation of surface plasmon polaritons (SPPs) in silver nanowires.
Abstract: This study demonstrates a novel light-emitting conjugated polymer (PCFOz) used to initiate excitation and propagation of surface plasmon polaritons (SPPs) in silver nanowires. Excitons in the polymer optically excited in close proximity to silver nanowires directly couple to the guided SPPs, and then propagate towards the wires' ends and light up. A tunable exciton–plasmon coupling is realized by varying the distance between PCFOz and Ag nanowires. Strongly efficient excitation of SPPs appears in the case of a spacer thickness of ∼10 nm. Moreover, photobleaching of the organic system is dramatically suppressed by separating the emitter and metal with a spacer, allowing at least 20 times improvement of photostability with a spacer thickness of 25 nm. Spectral dependence of exciton–plasmon coupling indicates that the nanowires' tips contain larger amount of red components. Study of emission decay dynamics demonstrates that the emission properties of PCFOz have been significantly modified by the proximity of Ag nanowires, generating more than 9-fold enhancement of PCFOz spontaneous emission. These results are believed to be important for the development of thin-film photonic–plasmonic waveguides, single photon source and various nanoscale fluorescence sensors.
22 citations
TL;DR: In this article, epoxy grafted nano-SiO2 is mixed with PTFE powder before sintering and calender rolling to improve creep resistance of directional polytetrafluoroethylene (PTFE) films.
Abstract: To improve creep resistance of directional polytetrafluoroethylene (PTFE) films, epoxy grafted nano-SiO2 is mixed with PTFE powder before sintering and calender rolling. The aligned macromolecular chains (especially those in amorphous region) of the composite films can be bundled up by the nanoparticles to share the applied stress together. In addition, incorporation of silica nanoparticles increases crystallinity of PTFE and favors microfibrillation of PTFE in the course of large deformation. As result, PTFE films exhibit lower creep strain and creep rate, and higher tensile strength and hardness. The work is believed to open an avenue for manufacturing high performance fluoropolymers by nano-inclusions.
16 citations
Patent•
01 May 2013
6 citations
TL;DR: In this article, a study of self-healing epoxy composites was conducted, which consisted of epoxy-loaded urea-formaldehyde microcapsules as the polymerizable binder and CuBr2(2-MeIm)4 (the complex of CuBr 2 and 2-methylimidazole) as the latent hardener.
Abstract: This paper reports a study of self-healing epoxy composites. The healing agent was a two-component one synthesized in the authors laboratory, which consisted of epoxy-loaded urea-formaldehyde microcapsules as the polymerizable binder and CuBr2(2-MeIm)4 (the complex of CuBr2 and 2-methylimidazole) as the latent hardener. Both the microcapsules and the matching catalyst were pre-embedded and pre-dissolved in the composites matrix cured by 2-ethyl-4-methylimidazole (2E4MIm), respectively. The data of curing kinetics show that the latent hardener CuBr2(2-MeIm)4 is not affected during the curing process of 2 h at 80°C, 2 h at 120°C and 2 h at 140°C, and heat deformation temperature of composites consisting of 2 wt% CuBr2(2-MeIm)4 and 5 wt% mcirocapsules cured at the same curing process is 180.2°C.
2 citations
01 Jan 2013
TL;DR: In this article, the sliding wear performance of epoxy-based nanocomposites is investigated and a general understanding of the role of nanoparticles and selection criterion for Nanocomposite components in terms of wear and friction performance has not yet been established.
Abstract: :
This chapter deals with the sliding wear performance of epoxy-based nanocomposites. It outlines the state of the art technology for preparing these nanocomposites. A general understanding of the role of nanoparticles and selection criterion for nanocomposite components in terms of wear and friction performance has not yet been established. This situation in turn leaves room for continuous researches in related areas.
1 citations
TL;DR: In this article, the authors provided epoxy composites with healing capability by predispersing a novel repair system in the composites matrix cured by 2-ethyl-4-methylimidazole (2E4MIm).
Abstract: Epoxy composites were provided with healing capability by pre-dispersing a novel repair system in the composites matrix cured by 2-ethyl-4-methylimidazole (2E4MIm). The healing agent consisted of ureaformaldehyde microcapsules containing epoxy and latent hardener CuBr2(2-MeIm)4 (the complex of CuBr2 and 2-methylimidazole). Single-edge notched bending (SENB) test were conducted to evaluate fracture toughness of the composites before and after healing. Moreover, healing efficiency was studied as a function of the content of the two-component healing agents. It was found that a healing efficiency of 173% relative to the fracture toughness of virgin composites was obtained in the case of 15 wt% epoxy-loaded microcapsules and 3 wt% CuBr2(2-MeIm)4.