Chemoselective epoxidation of hydroxyl-terminated polybutadiene (HTPB) using in-situ generated dimethyl dioxirane (DMD)

Abstract

Abstract-In this report hydroxyl-terminated polybutadiene (HTPB) was functionalized to epoxidized HTPBs containing various epoxide group moieties by using in situ-generated dimethyl dioxirane (DMD) as oxidant and tetra-n-butyl ammonium bromide as a phase-transfer catalyst (PTC) in convenient, simple and mild conditions. The system shows to be sensetive to electronic, steric and chain microstructure factors and reveals the high reactivity of cis in comparison with trans and vinyl double bonds. 1 H-NMR, 13 C-NMR and FT-IR spectra analysis of the products reveal that no significant side reactions take place in this system even at high epoxidation levels. Influences of various factors, i.e., reaction time and the PTC concentration were investigated in detail. Also, it was found that double bonds oxidized chemoselectively in comparision with terminal hydroxyl groups.

Block copolymer binders with hard and soft segments for scalable fabrication of sulfide‐based all‐solid‐state batteries

“…The structures of the PBD x ‐ b ‐PMMA y binders were investigated by Fourier transform infrared spectroscopy (FT‐IR) and 1 H nuclear magnetic resonance (NMR) analyses (Figure 1B and S1, Supporting Information). The peak intensity of the butadiene C═C stretching band at 1640 cm −1 and that of the 1,2‐vinyl double bonds at 911 cm −1 increased consistently in the sequence of PBD 57 PMMA 43 , PBD 79 PMMA 21 , PBD 87 PMMA 13 , and PBD 100 , while the ester stretching band of PMMA at 1730 cm −1 decreased with the same block variation 27,28 …”

Branched EHNBR and its properties with enhanced low-temperature performance and oil resistance

“…8 So far, there are three main ways to improve the low temperature performance of HNBR in literatures: (a) adopting a third monomer in the molecular structure of HNBR through graing reaction or copolymerization, as a exible side group to improve rubber molecular exibility and sabotage the molecular regularity; 9,10 (b) adding a plasticizer and adjusting the curing agent, reinforcing the agent of rubber mixing system in the vulcanization of rubber modied process; [11][12][13][14] (c) blending with other rubbers by physical or chemical blending methods, such as silicone rubber, uorine rubber, and ethylenepropylene rubber, combining merits of these rubber to improve the low temperature performance of HNBR. [15][16][17] Epoxidation is the common and effective methods to improve the properties of non-polar rubber, [18][19][20][21] but few studies report epoxidation of polar rubber. 22,23 Epoxide natural rubber (NR) has been widely studied 24,25 and realized industrialization.…”

Preparation of a P(THF-co-PO)-b-PB-b-P(THF-co-PO) triblock copolymer via cationic ring-opening polymerization and its use as a thermoset polymer

“…7 Until now, AM mechanism has been widely used in the CROP of cyclic ethers, acetals and esters, and corresponding polymers with narrow polydispersity and low cyclic oligomers content are obtained. 22 The other method was to bond some homopolymers that have large number of polar groups such as PCL or PEO to both ends of HTPB. Hydroxyl-terminated polybutadiene (HTPB) owns two hydroxyl groups at both ends of chain, and is widely used in polyurethane and adhesives, and especially used as a fuel binder in solid propellants.…”

“…The rst method was focused on the modication of the double bonds in HTPB main chain, such as the epoxidation of HTPB. 22 The other method was to bond some homopolymers that have large number of polar groups such as PCL or PEO to both ends of HTPB. 23,24 Unfortunately, these methods have certain limitations.…”