Synthesis, characterization, and studies on the solid-state crosslinking of functionalized vinyl cinnamate polymers

Abstract

Functionalized vinyl cinnamate monomers were synthesized by the reaction between hydroxyethylacrylate (HEA) and substituted cinnamoyl chlorides possessing electron releasing and withdrawing functional groups like chloro, methoxy, and nitro groups at the para position of the aromatic ring. The structures of these monomers were characterized by Fourier transform infrared (FTIR), 1 H-, and 13 C-NMR spectral techniques. The homopolymers of the synthesized monomers were obtained by the free radical solution polymerization in dimethylformamide (DMF) at 80ЊC for 12 h using azobisisobutyronitrile (AIBN) as a radical initiator. The sensitivity of these polymers towards light was studied by monitoring the photocrosslinking nature of the polymers by ultraviolet (UV) and FTIR techniques. The effect of the functional groups on the crosslinking efficiency was studied and compared with that of the unsubstituted polymer. The cyclobutane-type addition mechanism involved in the photocrosslinking phenomena was confirmed by the above spectral studies in the functionalized vinyl cinnamate polymers.

On‐line Monitoring of Polymerization and Cure

“…Crosslinking reactions in various resins have been studied by IR spectroscopy [24,25], and FTIR imaging using focal-plane array detection [26].…”

Photo-Inducible Crosslinked Nanoassemblies for pH-Controlled Drug Release

“…But it is also possible that cinnamates might simply undergo reversible isomerization in addition to photodimerization of adjacent cinnamates resulting in crosslinking (43). A clear isosbestic point in the UV/Vis spectrum can be observed when reversible isomerization is taking place.…”

“…A clear isosbestic point in the UV/Vis spectrum can be observed when reversible isomerization is taking place. The absence of clear isosbestic points in figure 4A indicates that cinnamate photodimerization through [2+2] cycloaddition between the double bonds of two adjacent cinnamates (illustrated in Figure 2) dominated cinnamate E/Z photoisomerization leading to the formation of core crosslinked piCNAs (43). In the meantime, the size, surface charge, and molecular weight of piCNAs were indistinguishable from piSNAs (Figure 5).…”

“…A photo-crosslinking reaction takes place between light sensitive cinnamate pendant groups on poly(ethylene glycol)-poly(aspartate) block copolymers (Figure 1B) through molecular rearrangement in response to light (43, 44). In addition, these block copolymers have hydrazide drug-binding linkers for acid-labile hydrazone conjugation with DOX (45, 46).…”

Synthesis and kinetic studies of UV‐curable urethane‐acrylates

“…The ratio of absorption of CϭC at a peak of 1,635 cm Ϫ1 to the absorption of aromatic C-H at a peak of 840 cm Ϫ1 was defined as the degree of reaction. 12 Figure 1…”