An approach to branched vinyl polymers through radical polymerization in the presence of 3mercaptohexyl methacrylate (MHM) as the chain transfer monomer is reported in this paper. In the case of polymerization at styrene 100 −MHM 5.0 −AIBN 2.0 , the molecular weight increased with conversion and reached a value of >7.3 × 10 5 g/mol at 99% conversion; in addition, the Zimm branching factor, g′, was less than 1 and decreased with conversion, when the formation of the branched chain and development of branching was supposed. The bridging units in the obtained polymer, generating from MHM, were cleaved to yield the primary chains. These results have confirmed the formation of branched polymers. Moreover, this study successful prepared branched poly(methyl methacrylate) and poly(vinyl acetate). This methodology proposes good prospects for scaling-up and thereby offers a wide range of branched vinyl polymers at low cost.

No abstract

This paper reports a new type of click chemistry via a phosphazene bases-catalyzed oxa-Michael addition of an alcohol to an acrylate.

Hyperbranched polymers with high molecular weights were synthesized by t-BuP2-catalyzed oxa-Michael addition polymerization of trifunctional hydroxyl and diacrylate monomers.

Two soluble polymers containing azobenzene chromophore in main chain were successfully synthesized from R-azide, ω-alkyne A-B type azobenzene monomers, 3 0 -ethynylphenyl[4-hexoxyl(2-azido-2-methylpropionate)phenyl]azobenzene (EHPA) and 3 0 -ethynylphenyl[4-(4-azidobutoxy)phenyl]azobenzene (EAPA), via thermal 1,3-dipolar cycloaddition in bulk. Compared to the polymers obtained from Cu(I)-catalyzed 1,3-dipolar cycloaddition ("click" chemistry), the polymers obtained from thermal 1,3-dipolar cycloaddition showed good solubility in common solvents like CHCl 3 and THF and good film-forming ability. The polymers were thermally stable up to 330°C. The structures of the main-chain azobenzene polymers were characterized by gel permeation chromatography (GPC), 1 H NMR, UV-vis, and FT-IR spectra. The photoinduced trans-cis isomerization of the polymers in chloroform (CHCl 3 ) solution was examined. With illumination of linearly polarized Kr þ laser beam at 413.1 nm, surface relief gratings formed on PEHPA2 spin-coating films were investigated.

The amide bond is one of the most pivotal functional groups in chemistry and biology. It is also the key component of proteins and widely present in synthetic materials. The majority of studies have focused on the formation of the amide group, but its postmodification has scarcely been investigated. Herein, we successfully develop the Michael additions of amide to acrylate, acrylamide, or propiolate in the presence of phosphazene base at room temperature. This amide Michael addition is much more efficient when the secondary amide instead of the primary amide is used under the same conditions. This reaction was applied to postfunctionalize poly(methyl acrylate-co-acrylamide), P(MA-co-Am), and it is shown that the amide groups of P(MA-co-Am) could be completely modified by N,N-dimethylacrylamide (DMA). Interestingly, the resulting copolymer exhibited tailorable fluorescence with emission wavelength ranging from 380 to 613 nm, which is a desired property for luminescent materials. Moreover, the emissions of the copolymer increased with increasing concentration in solution for all excitation wavelengths from 320 to 580 nm. Therefore, this work not only develops an efficient t-BuP 4 -catalyzed amide Michael addition but also offers a facile method for tunable multicolor photoluminescent polymers, which is expected to find a wide range of applications in many fields, such as in anticounterfeiting technology.

In this paper, we report radical polymerization in the presence of a peroxide monomer for the preparation of branched vinyl polymers.

Bibiao Jiang et al. Radical emulsion polymerization with chain transfer monomer: an approach to branched vinyl polymers with high molecular weight and relatively narrow polydispersity