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Aggregation-induced emission (AIE) has already been applied for in-situ monitoring living radical polymerization process. Here we utilized functionalized monomer TPEE as fluoresce probes for the in-situ monitoring of photo-induced RAFT-PISA process. Hydrophilic POEGA macro chain transfer agent (Macro-CTA) was first prepared with light sensitive CTA 4-Cyanopentanoic acid dithiobenzoate, and (2-(4-vinylphenyl)ethene-1,1,2-triyl)tribenzene (TPEE) was copolymerized with styrene to form the hydrophobic block under UV irradiation. The growth of hydrophobic block induced the self-assembly of polymer chains and the emission signal could be observed by naked eyes afterwards. The PL intensity increased with the increase of particle size, as well as the monomer conversion and molecular weight, owing to the enhancement of AIE monomer in the self-assembly latex particles. This no-invasive and facile approach to in-situ visualization and continuously monitoring of the photo-induced RAFT-PISA process might be helpful for both scientific research and commercial application. [ABSTRACT FROM AUTHOR]

Aggregation‐induced emission (AIE) technology has been demonstrated to be a facile approach for in‐situ monitoring atom transfer radical polymerization (ATRP). A series of tertraphenyl ethylene (TPE)‐containing α‐bromo compounds were synthesized and applied as ATRP initiators. The photoluminescent (PL) emission of the polymerization system is proved to be sensitive to the local viscosity owing to the AIE characteristics of TPE. Linear relationships between the resulting molecular weight Mn and PL intensity were observed in several polymerization systems with different monomers, indicating the variability of this technique. Compared to physical blending, the chemical bonding of the TPE group in the chain end has higher sensitivity and accuracy to the polymer segments and the surrounding environment. This work promoted the combination of the AIE technique and controlled living radical polymerization, and introduced such an optical research platform to the ATRP polymerization process. [ABSTRACT FROM AUTHOR]

Three kinds of star-shaped nylon 6 samples with different branched-chain length were prepared by the hydrolytic polymerization of ε-caprolactam using trimesinic acid as trifunctional reactant. The structure of prepared star-shaped nylons was characterized by infrared spectroscopy and H-NMR. Compared with linear-chain nylon 6, star-shaped nylons with the equivalent molecular weight present higher melt flow indices and lower relative viscosities due to decreased molecular dimensions and reduced hydrogen bond interactions between neighboring molecules. The molecular weights of the products were determined by end-group titration and H-NMR, and the molecular weight distributions (MWDs) were evaluated by gel permeation chromatography. The results show that the molecular weight decreased and the MWD narrowed as the concentration of trimesinic acid increased. Wide-angle X-ray diffraction patterns of star-shaped and linear-chain nylons show that increasing the concentration of trimesinic acid leads to good symmetry and high crystallizability, but this also degrades crystal perfection as observed using a polarized optical microscope. The viscosity of nylon 6 can be significantly reduced while maintaining its mechanical performance through the use of star-branching and an appropriate concentration of trimesinic acid. [ABSTRACT FROM AUTHOR]