Oxidation-responsive polyether block copolymers lead to non-ionic polymer surfactants with multiple amine N-oxides

2019 ◽  
Vol 10 (13) ◽  
pp. 1569-1574 ◽  
Author(s):  
Jan Blankenburg ◽  
Martin Stark ◽  
Holger Frey
Keyword(s):  
Block Copolymers ◽  
Propylene Oxide ◽  
Tertiary Amines ◽  
Ionic Polymer ◽  
Polymer Surfactants ◽  
Poly Propylene

Oxidation of tertiary amines leads to multiple amine N-oxide moieties and a highly polar polyether structure. Combination with the apolar poly(propylene oxide) affords unusual surfactants.

scholarly journals Tertiary Amines Paired with Trialkyl Boranes: A Simple Organocatalyst for Fully Alternating Copolymerization of Carbon Dioxide and Propylene Oxide

2020 ◽  
Author(s):  
Xing-Hong Zhang
Keyword(s):  
Carbon Dioxide ◽  
Small Molecules ◽  
Propylene Oxide ◽  
Average Molecular Weight ◽  
Tertiary Amines ◽  
Carbon Dioxide Co2 ◽  
Poly Propylene ◽  
Alternating Copolymerization ◽  
Completely Alternating ◽  
Huge Challenge

Metal-free synthesis of fully alternating polycarbonates from carbon dioxide (CO2) and epoxides is highly desired but a huge challenge. Here, we disclose the combination of tertiary amines with trialkyl boranes for completely alternating copolymerization of CO2 with epoxides. Triethylamine (TEA) pairing with triethyl borane (TEB), the simplest catalyst for the copolymerization of CO2 and propylene oxide (PO), afforded fully alternating poly(propylene carbonate) (PPC) with a turnover frequency (TOF) of 54 h-1 at 60 oC. Remarkably, diamine such as, N,N,N',N'-tetraethylethylenediamine (TEED) and triamine such as N,N,N',N'',N''-pentamethyldiethylene triamine (PMDETA) pairing with TEB exhibited improved the copolymer selectivity of up to 99%. Supplementally, the effect of trialkylborane structure on the copolymerization were also investigated. Moreover, PPCs prepared from these tertiary amines/ trialkyl boranes Lewis pairs showed the head-to-tail diad content of around 80%. The number-average molecular weight of PPC was up to 56.0 kg/mol with narrow distribution (Đ =1.16) and could be easily adjusted by simply varying the feeding ratios. The 1H NMR spectra and MALDI-TOF-MS spectra suggest that both tertiary amine-activating CO2 and TEB-masked end anions cooperatively promote the fully alternating CO2/epoxide copolymerization. This work provides an organocatalytic platform for well-defined CO2/epoxide copolymers using simple small molecules with high atomic utilization.<br>

Elastomer Blends

1974 ◽  
Vol 47 (3) ◽  
pp. 481-510 ◽  
Author(s):  
P. J. Corish ◽  
B. D. W. Powell
Keyword(s):  
Block Copolymers ◽  
Propylene Oxide ◽  
Polymer Chains ◽  
Rubber Compound ◽  
Repeat Units ◽  
Rubber Compounds ◽  
Broad Concept ◽  
Poly Propylene ◽  
Styrene Butadiene ◽  
Composite Article

Abstract Mixtures are difficult to define within the range of materials employed in the rubber and plastic industries. A composite article such as a tire is a mixture of wire (metal), textile cord (organic fiber), and rubber compounds. The rubber compound itself is a mixture of elastomer, filler, and, usually, extender. Moreover, the elastomer may be a mixture of two or more rubbers. On a smaller scale, the elastomer may contain ‘blocky’ segments or crystalline portions along the polymer chains which act as ‘reinforcing’ agents or stiffeners. These may be similar to the repeat units of the elastomeric part, e.g., isotactic—atactic block copolymers of poly(propylene) or poly(propylene oxide); or different from it, as in the stereo block styrene—butadiene thermoplastic copolymers. Two types of elastomer may of course, be copolymerized or one elastomeric type may be grafted onto another. Furthermore, certain catalysts could cause simultaneous homopolymerization of two monomers. All the foregoing systems are different facets of the broad concept of blends, but some selection is obviously needed. In this review, most emphasis will be placed on elastomer—elastomer blends including their preparation from the constituent elastomers. Reference will be made to elastomer—plastic blends prepared from separate materials and by block/graft type reactions. Blends of one plastic with another lie outside the scope of this review.

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