Benzoylformamide (BFA) derivatives are proposed as new photocaged bases with good solubility in epoxy resin. Initially their structures were confirmed by 1H NMR, 13C NMR, and elemental analysis. Next, we detail their thermal stability, solubility behavior, and photolysis products. Furthermore, the model photo-latent anion polymerization (AP) of epoxide system in the presence of BFA-dBA (N,N-dibenzyl-2-oxo-2-phenylacetamide) as a photocaged base has been investigated, and excellent photopolymerization profile is obtained.Benzoylformamide (BFA) derivatives as new photocaged bases for photo-latent anion polymerization are proposed.

Thioxanthone-based N-phthalimidoamino acid ammonium salt (thioxanthen-DBU) as a photocaged base was synthesized and characterized. The photochemical properties and initiation mechanism were analyzed. It was found that the compound absorbs over the UV and visible region with relatively high absorption coefficients. Furthermore, the covalent binding of N-phthalimidoamino acid and type II chromophores (thioxanthone, TX) remarkably improved the photoreactivity. Specifically, in combination with a benzoyl peroxide initiator, thioxanthen-DBU was able to initiate the amine-mediated redox photopolymerization of trimethylol propane triacrylate (TMPTA), and an excellent photopolymerization profile was obtained.Thioxanthone-based N-phthalimidoamino acid ammonium salt (thioxanthen-DBU) as a photocaged base was reported for highly effective redox photopolymerization.

UV-curable tung oil based resins of GMA-PCDMAT and GMA-ICDMAT were synthesized via Diels–Alder reaction with maleic anhydride (MA), subsequent nonisocyanate polyurethane (NIPU) reaction with piperazine-1,4-dicarboxylic acid bis-(2-hydroxy-ethyl) ester (PCD) or isophoronediamine-1,4-dicarboxylic acid bis-(2-hydroxy-ethyl) ester (ICD) and acrylated modification with glycidyl methacrylate (GMA). The final chemical structures of GMA-PCDMAT and GMA-ICDMAT depend on the feeding ratio of MA, tung oil, PCD (or ICD) and GMA. Results of 1H NMR and FTIR revealed that the targeted tung oil-based resins were successfully obtained. All the obtained resins had broad molecular weight distributions. UV-curing kinetic and thermal properties were respectively revealed by photo-DSC, DSC and TG. Higher concentration of CC bonds led to faster curing rate but lower final conversion of CC bonds. All the cured films had two glass transitions, one in the range of 8–10 °C and another in the range of 46–48 °C. All the cured films possessed excellent thermal stability, and the start temperature of decomposition (Tsta) was as high as 350 °C, implying that they can be used for UV coatings for the substrates with high-temperature resistance. The introduction of structure of NIPU is helpful to enhance adhesion of the cured films with substrates.Highlights► UV-curable tung oil resins are prepared via Diels–Alder reaction, modification of nonisocyanate polyurethane (NIPU) and acrylates. ► NIPU improves tung oil based resins as well as solves problems of traditional PU technology. ► Acrylated modification keeps advantage of fast cure along with industrial and commercial acceptance.

Phototriggered base proliferation as a highly efficient domino reaction is presented for creating functionally photo-screened materials, providing a strategy for the photopolymerization of shadow areas via chemically diffuse amines toward the nonirradiated areas during polymerization. By integrating proliferated amines with a peroxide initiator (dibenzoyl peroxide, BPO), phototriggered self-propagating polymerization of acrylate monomers in three-dimensional space was achieved. The advantages of this approach lie in its enhanced photosensitivity, increased propagating velocity, and elevated double-bond conversion (90%) while reducing the local high temperature and the minimum BPO concentration that sustain a traveling front. Astonishingly, the propagating velocity and local maximum temperature can be well-modulated by varied BPO concentration and the appropriate amount of BA-BPD (1-(9-fluorenylmethoxycarbonyl)-4-benzylpiperidine) concentration, respectively. Finally, functionally photo-screened material containing carbon nanotubes was successfully prepared by phototriggered base proliferation reactions.

The article presents a highly effective strategy for photopolymerization of acrylates via photolatent redox-accelerated reaction based on the synergistic photoinitiating systems containing photolatent superbase and readily available peroxides. Polymerization of acrylates could be instantly initiated with the effective interaction between the photogenerated amine and peroxides. Due to the persistent interaction of produced longeval amine with peroxides, remarkable post conversion after irradiation, which is significant for radiation crosslinking of photo-screened materials, was thus initially achieved in photoinitiated free radical polymerization. To explore the synergistic interactions of the photoinitiating systems, the effect of peroxide structures and QA-DBU:BPO ratios had been examined by RTIR, showing that all peroxides are applicable as the final conversion rate of acrylates is concerned. Further, BPO and CHP significantly accelerated the photopolymerization rate in air atmosphere. The synergistic efficiency of QA-DBU and BPO as a photopolymerization initiatiation system was close to that of the conventional D-1173 photoinitiator.Graphical abstract

Rapid and highly efficient side-chain functionalization of polypeptides was achieved via combination of ring-opening polymerization of a new clickable monomer of γ-propargyl-L-glutamateN-carboxyanhydride (PLG-NCA) and thiol-yne photochemistry, which provides a convenient and universal route to prepare diverse polypeptide-based biomimetic hybrid materials.

Frontal photopolymerization was applied to fabricate polymer/nanozirconia hybrid material by using acrylates as polymerizable components and tetrabutyl zirconate (TBZ) as the precursor of nanozirconia, respectively. The nanozirconia particles were in-situ generated with the polymerization front traveling and gradiently dispersed in the simultaneously formed polymer rod. The iodonium salt was utilized as photoacid generator to produce protonic acid and drive TBZ into nanozirconia particles. With the frontal polymerization traveling downward, the particle size and concentration of zirconia increased, but layer-resolved conversion of TBZ decreased. The particle size of zirconia could be reduced remarkably by the protection of monoalkyl titanate bearing six long chains. The refractive index of the hybrid rod was found to increase from top to down. The top–down layer-resolved storage modulus of the hybrid rod increased due to nanoparticle filling effect but decreased beyond the depth of 4 cm from the top, which may be ascribed to particle aggregation.

Rapid and highly efficient side-chain functionalization of polypeptides was achieved via combination of ring-opening polymerization of a new clickable monomer of γ-propargyl-L-glutamateN-carboxyanhydride (PLG-NCA) and thiol-yne photochemistry, which provides a convenient and universal route to prepare diverse polypeptide-based biomimetic hybrid materials.