Synthesis and characterization of terminally functionalized and epoxidized hydroxyl-terminated polybutadiene

A Creative Approach to Prepare a Macromolecular Flame Retardant with Flexibility: DOPO-Modified Epoxidized Polybutadiene

“…The peak c (δ = 5.4 ppm) was assigned to two types of H protons located at the double bonds (−C H C H −) of 1,4-PB and those (−C H CH 2 ) of 1,2-PB. , The peak d (δ = 5.0 ppm) was assigned to the H proton located at end of the double bonds (−CHC H 2 ) of 1,2-PB. , After the CC bonds were partially oxidized into epoxy groups to generate EPB, peak e was observed, which was assigned to the H protons in the epoxy group (δ = 2.9 ppm for cis- and δ = 2.7 ppm for trans-), , thus confirming the formation of EPB. Once EPB was modified with DOPO to generate EPB–DOPO via the ring-opening addition between the P–H bond and the C–O–C bond, the epoxy group was opened, and in the meantime, peak a (δ = 3.4 ppm) was observed, which was assigned to −OH . In addition, peak b (δ = 7–8 ppm) that represents H protons on the biphenyl ring originally in DOPO was found in the final product, , and this also provided a convincing evidence for the formation of EPB–DOPO.…”

“…Once EPB was modified with DOPO to generate EPB−DOPO via the ring-opening addition between the P−H bond and the C−O−C bond, the epoxy group was opened, and in the meantime, peak a (δ = 3.4 ppm) was observed, which was assigned to −OH. 22 In addition, peak b (δ = 7−8 ppm) that represents H protons on the biphenyl ring originally in DOPO was found in the final product, 17,18 and this also provided a convincing evidence for the formation of EPB−DOPO. Based on the previous studies 16,20,22 and the 1 H NMR spectrum in Figure 1, the epoxidation degree (E %) and the relative molar content of DOPO (D %) were calculated according to eqs 1 and 2, respectively.…”

“…In addition, peak b (δ = 7–8 ppm) that represents H protons on the biphenyl ring originally in DOPO was found in the final product, , and this also provided a convincing evidence for the formation of EPB–DOPO. Based on the previous studies ,, and the 1 H NMR spectrum in Figure , the epoxidation degree ( E %) and the relative molar content of DOPO ( D %) were calculated according to eqs and , respectively. The calculated values of E % for EPB5%, EPB10%, and EPB15% and those of D % for EPB5%–DOPO, EPB10%–DOPO, and EPB15%–DOPO were all very close to the corresponding preset theoretical values.…”

“…The molar content of the grafted DOPO was the same as that of the formed −OH. Thereby, the relative molar content ( D %) of DOPO grafted onto EPB can be calculated via the molar content of the formed −OH relative to that of the original double bonds with the chemical shift at 3.4 based on eq …”

Cloisite 15Aº nanoclay as an effective PTC for the epoxidation of hydroxyl terminated polybutadiene (HTPB)

“…Oxone  performs oxidations in biphasic systems using immiscible co-solvents in mixture with a phase-transfer catalyst (PTC) [18,19] . Previously, we reported polybutadiene and HTPB epoxidation using in-situ generated DMD in the presence of tetra-n-butyl ammonium bromide as a phase transfer catalyst (PTC) [20,21] , MoO 3 [22] , transition metal salts [23] , copper (II) complex [24] , Nano TiO 2 [25] and Cloisite 30B as a PTC [26,27] . In the continuation of our previous works on epoxidation reactions, we decided to epoxidize HTPB using modified nanoclay called Cloisite 15Aº as the phase-transfer catalyst.…”