Intramolecular cyclization of long-chain hyperbranched polymers (HyperMacs) from A₂ + B_n step-wise polymerization

Abstract

According to the definition and physical meaning of m-CI, as a contrast, a normalized parameter m-CI can be used to analyze intramolecular cyclization of HyperMacs, which can eliminate the difference of degree of functionality (n value in A 2 +B n strategy). As shown in Figure 12, a uniform criteria value of 1 was used as a reference for completely cyclized polymers. Once normalized, the m-CI located in the range of 0.77-0.93 for the HyperMacs-C 2 , C 4 and C 8 (polytriazole), according to the change characteristics as shown in Figure 7. Besides, the m-CI of HyperMacs-PEG-polytriazole is equal to 0.86 (in the range of 0.5-1.0). And the m-CI of HyperMacs-polyester is changed from 1.01-1.07 to 0.67-0.71 (unpurified) and 1.03-1.12 to 0.69-0.75 (purification three times by solvent precipitation), respectively. Obviously, the trend of either N A /N B or m-CI is the same. In another word, m-CI closer to 1 means higher intramolecular cyclization of HyperMacs. The long chain backbones can induce more intramolecular cyclics during the A 2 +B 3 step-wise polymerization either via Cu-catalyzed azide-alkyne cycloaddition click chemistry or classic esterification reaction.

The Synergy of Double Cross-linking Agents on the Properties of Styrene Butadiene Rubber Foams

“…The characteristic bands at 2915 and 2854 cm −1 are assigned to C-H stretching deformation of -CH 3 and -CH 2 - in SBR structure unit3435. Moreover, with the increasing of DCP content, the intensity of the peaks from sample 1 to 6 is increased, which is related to the decomposition of DCP.…”

Long‐Chain Hyperbranched Polymers: Synthesis, Properties, and Applications

“…The resulting supramolecular LCHBP showed temperature‐dependent assembly behavior. To understand the A 2 + B x polymerization mechanism, a certain rational and quantitative analyzation was conducted by Kong et al., and a macro‐cyclic index was proposed to analyze and quantitatively characterize the intramolecular cyclization during the A 2 + B x process for synthesizing HBPs …”

“…or both ( Figure 1). [27,[70][71][72][73][74][75][76][77][78] Given that a simple coupling reaction of an A 2 monomer and a B x monomer will produce an "AB x-1 " type monomer, we can primarily regard this A 2 + B x copolymerization as "AB x-1 "-type strategy. Therefore, to afford LCHBPs, at least one of the A 2 and B x monomers should be macromonomer for introducing long polymeric subchains, and the x value must be greater than or equal to 3 (x − 1 ≥ 2) for generating hyperbranched topologies.…”

“…To understand the A 2 + B x polymerization mechanism, a certain rational and quantitative analyzation was conducted by Kong et al, and a macro-cyclic index was proposed to analyze and quantitatively characterize the intramolecular cyclization during the A 2 + B x process for synthesizing HBPs. [75] In contrast with the above strategy based on A 2 macromonomer and B 3 small molecular monomer, there were also several reports based on the A 2 + B 3 approach, but contrarily, A 2 small mole cular monomer and B 3 macromonomer with a high molecular weight. For example, poly(ester urethane) LCHBP was synthesized from A 2 monomer of isocyanate functionalized 1,4-butanediol and triol-functionalized polycaprolactone as the B 3 macromonomer.…”

“…[21, Moreover, LCHBPs can also be easily afforded through certain copolymerizations by using high molecular weight macromonomers or small molecular monomers, or simultaneously both, as building blocks via A 2 + B x (x ≥ 3) or AB + AB x (x ≥ 2) copolymerization process. [27,[63][64][65][66][67][68][69][70][71][72][73][74][75][76][77][78] Additionally, the famous self-condensing vinyl polymerization (SCVP) [79] usually affording conventional HBPs with short subchains has Long-Chain Polymers By combining the virtues of conventional linear and hyperbranched polymers, long-chain hyperbranched polymers (LCHBPs) have attracted great attention. Therefore, a comprehensive summary of the research progress of LCHBPs is presented, with a particular focus on their synthetic strategies, unique properties, and potential applications.…”