Photoinduced atom transfer radical
polymerization (ATRP) has been
proved to be a versatile technique for polymer network formation.
However, the slow polymerization rates of typical ATRP limited its
application in the field of additive manufacturing (3D printing).
In this work, we introduced carbon quantum dots (CQDs) for the first
time to the ATRP in aqueous media and developed an ultrafast visible-light-induced
polymerization system. After optimization, the polymerization could
achieve a high monomer conversion (>90%) within 1 min, and the
polydispersity
index (PDI) of the polymer was lower than 1.25. This system was then
applied as the first example of ATRP for the 3D printing of hydrogel
through digital light processing (DLP), and the printed object exhibited
good dimensional accuracy. Additionally, the excellent and stable
optical properties of CQDs also provided interesting photoluminescence
capabilities to the printed objects. We deduce this ATRP mediated
3D printing process would provide a new platform for the preparation
of functional and stimuli-responsive hydrogel materials.
Our findings show that leonurine reduces synovial inflammation and joint destruction in RA through the NF-κB and mitogen-activated protein kinases pathways. Leonurine has potential as a therapeutic agent for RA.
Larger QDs result in a higher polymerization rate and a better fit of Mn,GPC with Mn,theoretical for PET-RAFT polymerization using CdSe QDs photocatalysts.
A Se/CMK-3 composite was in situ synthesized, exhibiting large capacity, high rate performance and excellent long-term cycling stability for Li-ion intercalation.
Rheological properties of nylon-1212 have been studied by means of Haake Rheometer. The effect of shear rate and temperature on the apparent vicosity of nylon-1212 was discussed. A correlation of non-Newtonian index with the temperature was obtained. The results showed that the apparent viscosity decreases with the increase of the temperature. With increasing shear rate, shear thinning of nylon-1212 was observed clearly. From the relation of the temperature dependence of the polymer, we obtained the viscous flow activation energy. We conclude that the apparent viscosity is sensitive to temperature at lower shear stress because of higher viscous flow activation energy, and the temperature affect on the apparent viscosity becomes weaker at higher shear stress because of lower viscous flow activation energy. We have investigated the creep and elastic recovery of nylon-1212. A creep test was carried out to define the linear viscoelastic range as 1.0 and 5.0 Pa for 195 and 190°C nylon-1212 melts, respectively. A time-dependent response was found for the creep and recovery phases at a lower applied shear stress. However, at higher shear stress, the creep and recovery phases were time-independent.
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