A novel P‐S‐Si‐based cage‐structural monomer for flame‐retardant modification of unsaturated polyester resin

Abstract

Currently, the issue of improving the flame‐retardant performance of unsaturated polyester resin (UPR) has drawn a lot of attention. In this study, methyl vinyl di (1‐thio‐2,6,7‐trioxal‐1‐phosphabicyclo [2.2] octane‐4‐methoxy) silane (MVDOS) with P‐N‐Si‐based cage unit was synthesized, and it was utilized as a reactive flame‐retardant monomer to modify UPR. The UPR/MVDOS composites were prepared by introducing different ratios of MVDOS into UPR via the reaction of crosslink. The efficiency of the resulted composites was investigated by using the limiting oxygen index (LOI), vertical burning test, and cone calorimeter test. The results showed that the composites reached the V‐0 rate without dripping, and the LOI value was 29.1% when the content of MVDOS was as low as 18 wt%. Cone calorimeter tests revealed the peak of heat release and CO production of UPR/MVDOS‐18 were 238.2 KW/m2 and 0.0167 g/s, which were respectively lower than the ones of neat UPR. The introduction of MVDOS also increased the stability of UPR composites. Furthermore, the scattering electron microscopy, laser Raman spectroscopy, and X‐ray photoelectron spectroscopy studies revealed that the incorporation of MVDOS stimulated the UPR matrix to generate char layer with increased graphitization degree, which provided a good barrier to prevent heat and oxygen from being transferred and then protected the materials inside from further burning. This research provides a new way to obtain flame‐retardant UPR composites with high performance.

Fire-retardant unsaturated polyester thermosets: The state-of-the-art, challenges and opportunities

“…Recently, Methyl vinyl di (1-thio-2, 6, 7-trioxal-1-phosphabicyclo [2.2] octane-4methoxy) silane (MVDOS) was also investigated as a comonomer for UP thermoset (n). When the composition ratio of MVDOS reached 18 wt%, the vertical fire test passed V-0 rating with an LOI value of 29.1% [49]. The PHRR and THR reduced by 57% and 28% to 238.2 KW/m 2 and 85.9 MJ/m 2 , respectively.…”

“…3. a) Chemical structure of FR monomers were used to synthesise an intrinsic fire-retardant UP: HCHDA [32], TBPA [33], TCPA [33], TBBA [34], BMP [35], DOPO-MA [36], DDP [37]; b) Chemical structure of vinyl comonomers for fire-retardant UP systems: DASPP [38], DMVBP [39], EACGP [40], PDAP [41], ODOPB-AC [42], TAOPO [43], DHP [43], TAP [44], TDCAA-DOPO [45], DTAP [44], DT [46], TGICAA-DOPO [47], BADPS [48], MVDOS [49]. reduced flexural strength from 24.21 MPa to 18.34 MPa.…”

Enhancing mechanical and electrical properties of phthalic anhydride‐based unsaturated polyester resin by structural modification using methylhexahydrophthalic anhydride

“…For instance, the incorporation of phosphorus‐containing monomer (1‐oxo‐2,6,7‐trioxa‐1‐ phosphabicyclo‐[2.2.2]octane‐methyl diallyl phosphate, PDAP) into UPRs led to a remarkable decrease in heat release capacity and an enhanced flame retardancy. [ 13 ] A significant improvement of the flame retardancy could also achieved by blending UPRs with 9,10‐dihydro‐10[2,3‐di(hydroxy carbonyl)propyl]‐10‐phosphaphenanthrene‐10‐oxide (DDP), [ 14 ] methyl vinyl di (1‐thio‐2,6,7‐trioxal‐1‐phosphabicyclo [2.2] octane‐4‐methoxy) silane (MVDOS) to PA‐based UPRs, [ 15 ] ammonium polyphosphate, [ 16 ] montmorillonite, [ 17 ] and many other additives. [ 18 ] Halogen compounds that can be mentioned include chlorendic acid, tetrabromophthalate, which also significantly enhance the flame retardancy of UPR, although they have been considered as environmentally polluting methods because of the emissions of HCl, HBr gases.…”

ADOPO‐anchored benzothiadiazole derivative toward efficiently P/N/S synergistic flame retarding of epoxy thermoset

“…Among the reported multiple elements synergistic flame‐retardants, DOPO‐based phosphorus‐containing flame retardants bridging with other elements stood out as the most promising candidates for fabricating the high flame‐retarded polymers due to their multiple flame‐retardant effects, high flame retardant efficiency, low environmental toxicity, and easy‐to‐design 6 . So far, several synergistic systems (e.g., P/N, P/Si, P/S, P/N/S, P/N/Si) were developed and proved that the synergistic effects significantly improved the flame retardancy of the polymers at low flame retardant addition 24–28 . Meanwhile, as a kind of N/S containing molecular, benzothiadiazole (BTD) was widely applied to organic solar cells, bioimaging, electronic materials, fluorescent probes, plant activators, and so forth, owing to their attractive physicochemical and photophysical properties 29 .…”

“…6 So far, several synergistic systems (e.g., P/N, P/Si, P/S, P/N/S, P/N/Si) were developed and proved that the synergistic effects significantly improved the flame retardancy of the polymers at low flame retardant addition. [24][25][26][27][28] Meanwhile, as a kind of N/S containing molecular, benzothiadiazole (BTD) was widely applied to organic solar cells, bioimaging, electronic materials, fluorescent probes, plant activators, and so forth, owing to their attractive physicochemical and photophysical properties. 29 Therefore, the development of benzothiadiazole chemically binding with DOPO flame retardants have a great potential to speed up the high-value functional polymers and expand their applications in the new high-tech industry.…”