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A crosslinked silicone elastomer is prepared by utilizing polydimethylsiloxane as the host material and disulfide bond-containing silane as the crosslinking agent. By taking advantage of the sunlight activated metathesis of the included disulfide bonds, the crosslinked silicone elastomer can be self-healed and recycled for multiple times without any catalyst under sunshine. A series of verification...
Polyvinyl chloride (PVC), a typical commodity thermoplastic polymer, is enabled for self-healing using nucleophilic thiol-click chemistry. A healing agent consisting of bifunctional monomer glycidyl methacrylate (GMA), polythiol pentaerythritol tetrakis (3-mercaptopropionate) (PETMP) and basic catalyst 2,4,6-tris(dimethylaminomethyl) phenol (DMP-30) shows good wetting of the PVC matrix, fast reaction...
To provide room temperature self-healing ability to crosslinked epoxy elastomer, alkoxyamine-based diglycidyl ether (DiEPO) is synthesized and cured with polythiol. The C–ON bonds in both the alkoxyamine monomer and the cured epoxy are able to be synchronously cleft and recombined, achieving a dynamic reversible equilibrium state. This habit can thus be used as a healing chemistry for repeatedly re-bonding...
To provide self-healing ability to polyurethane elastomer, alkoxyamine-based diol was synthesized and reacted with tri-functional homopolymer of hexamethylene diisocyanate (tri-HDI) and polyethylene glycol (PEG). Because alkoxyamines acted as crosslinkers of the resultant polyurethane, the thermally reversible fission/recombination of C–ON bonds in alkoxyamine moieties enabled repeated crosslinking...
In this work, a multilayered microcapsule is proposed and prepared for use in self-healing polymers. Reactants for atom transfer radical polymerization (ATRP) are separately introduced into different places of the microcapsule to construct a latent ATRP reactor. When a polymer containing these capsules is damaged, crack induced breakage of the tiny vessels would lead to contact of the aforesaid reactants...
A novel polyurethane was synthesized, which consisted of isophorone diisocyanate, polyethylene glycol and photo-reversible moiety 5,7-bis(2-hydroxyethoxy)-4-methylcoumarin. By taking advantage of reversible photodimerization and photocleavage habit of coumarin, the polyurethane can be repeatedly crosslinked and de-crosslinked under successive UV irradiations at 350 and 254 nm. More importantly, damages...
To investigate the influence of molecular structure such as side chain on phase separation process in solution, naphthalene-labeled poly (octadecyl vinyl ether) (PODVE) with long side chains was synthesized by living cationic polymerization. Rayleigh Light scattering (RLS) and photoluminescence (PL) studies indicated that side chain played a dominant role in phase separation process in PODVE/dichloromethane...
Self-healing polystyrene (PS) composites were fabricated, in which glycidyl methacrylate (GMA)-loaded microcapsules were embedded. Because the matrix PS was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization, it kept living characteristics and was able to resume the polymerization so long as monomers were available. Upon damage of the composites, the GMA released...
To prepare epoxy materials with improved thermal remendability, two types of epoxy resins (N,N-diglycidyl-furfurylamine (DGFA) and furfuryl glycidyl ether (FGE)), which were synthesized in the authors' lab and contained different proportions of furan and epoxide groups, were blended and cured by anhydride and maleimide. Like the cured version of either DGFA or FGE alone, the cured blends of DGFA and...
Hyperbranched aromatic polyamide grafted nano-silica particles were successfully prepared via “one-pot” melt polycondensation. The particles were firstly treated with a silane coupling agent to introduce amine groups as the growth points, and then grafting of the hyperbranched polymers started from the modified surface. The percentage grafting can be as high as 32.8%. The key reaction conditions,...
Our earlier work developed epoxy based self-healing composites with embedded dual microcapsules, which contain unreacted epoxy as the polymerizable component and mercaptan and tertiary amine catalyst as the hardener, respectively. Self-healing was allowed to proceed rapidly, offering attractive repair effectiveness. To give full play to the healing agent, influences of a series of factors on healing...
A two-component healing agent consisting of epoxy- and ((C 2 H 5 ) 2 O·BF 3 )-loaded microcapsules was synthesized and applied to fabricate self-healing epoxy composites. Curing of epoxy healing agent catalyzed by (C 2 H 5 ) 2 O·BF 3 belongs to cationic chain polymerization, which is characterized by fast reaction at ambient temperature...
A novel method was proposed to prepare boron trifluoride diethyl etherate ((C 2 H 5 ) 2 O·BF 3 )-loaded microcapsules. To protect the high activity of (C 2 H 5 ) 2 O·BF 3 , hollow microcapsules were prepared via UV-initiated polymerization in emulsion with the aid of CO 2 microbubble templates, evacuation, and immersion in (C...
Microcapsules containing curing agent for epoxy were successfully prepared by in situ polymerization with poly(melamine–formaldehyde) (PMF) as the shell material and high-activity polythiol (pentaerythritol tetrakis (3-mercaptopropionate), PETMP) as the core substance. Having been encapsulated, the core material PETMP had the same activity as its raw version. The synthesis approach was so improved...
A novel method for producing epoxy resin-containing microcapsules via UV-initiated radical copolymerization in an epoxy emulsion was developed. Epoxydiacrylates and a polymerizable emulsifier were employed as the wall-formers, which tended to accumulate at the exterior layer of epoxy colloids during the emulsification process. Upon exposure to UV light, the shell phase consisting of the wall-formers...
To promote dispersion of nano-silica in polypropylene (PP), a polymerizable foaming agent p-vinylphenylsulfonylhydrazide was synthesized and grafted onto the nanoparticles via free-radical polymerization. It was found that the grafted poly(p-vinylphenylsulfonylhydrazide) played dual role when being melt mixed with PP. The side sulfonylhydrazide groups were gasified to form polymer bubbles, leading...
To reveal the role of crystalline phase in the matrix polymer of gas sensing conductive polymer composite materials, a series of triblock copolymer polystyrene-b-poly(ethylene glycol)-b-polystyrene (PS–PEG–PS) was synthesized by atom transfer radical polymerization (ATRP). The copolymers have similar molecular weights but different fractions of the crystalline PEG segments. As a result, the ratio...
Low nano-silica loaded polypropylene composites are produced by conventional compounding technique in which the nanoparticles are grafted by polystyrene using irradiation beforehand. A high interfacial stress transfer efficiency is demonstrated by both strengthening and toughening effects perceived in tensile tests. The role of the modified nanoparticles in improvement of tensile properties of the...
An irradiation grafting method was applied for the modification of nanoparticles so that the latter can be added to polymeric materials for improving their mechanical performance, using existing compounding techniques. The following items are discussed in particular, in this paper: (a) chemical interaction between the grafting monomers and the nanoparticles during irradiation; (b) properties including...
The interfacial structure of carbon fiber/polyetheretherketone (CF/PEEK) composites has been studied with Raman and X-ray photoelectron spectroscopy. Analysis of the fibers isolated from the composites proved that the polymer segments tended to form strong interactions with the fiber on the surface. Study of the fiber with a thin layer of PEEK coating further revealed that melting of the polymer plays...
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