Tandem polymerization

Figure 4 Tandem polymerization catalysts for the preparation of branched polyethylenes.

Acrylate-ethylene copolymers have also been synthesized using the same tandem polymerization/hydrogenation methodology. Commercially, ethylene-... 

LCB results from the copolymerization of ethylene or propene with vinyl-terminated polymer formed during the polymerization. Since vinyl double bonds are more reactive in copolymerization than other types of double-bond end groups, LCB is increased under conditions that generate higher vinyl contents. This can be accomplished by choice of initiator and reaction conditions. Tandem polymerization is also useful, such as by using two initiators, one of which produces a vinyl-terminated oligomer (referred to as a macromonomer or macromer) [Komon and Bazan, 2001 Quijada et al., 2001 Wang et al., 2000]. 

A similar strategy was employed to synthesize poly(arylene thiopheny-lene) 50 in a one-pot three-component tandem polymerization. The polymerization of terephthaloyl dichloride, l,2-bis(4-ethynylphenyl)-1,2-diphenylethene, and 2-mercapto acetate proceeds smoothly under the previously reported mild reaction conditions to afford the desired polymeric structure in excellent yields (up to 97%) and high molecular weights of up to 156,000. Interestingly, a strict stoichiometry of the starting materials is not required (Scheme 30) (2014MM(47)4920). 

Other tandem polymerizations of diacid chlorides and dialkynes have recendy been covered in an excellent review by Hu et al. (2016MCP(217)213). 

Recently a universal alkoxyamine initiator (16) was reported that allows LFRP of monomers other than styrene. This new alkoxyamine was discovered utilizing high speed combinatorial synthesis techniques. It has been used to make styrene-butadiene, S-BA, and S-MMA block copolymers directly without the need for tandem polymerization techniques (258). 

Jayaratne, K. C. Keaton, R. J. Henningsen, D. A. Sita, L. R. Living Ziegler-Natta cyclopolymerization of nonconjugated dienes New classes of microphase-separated polyolefin block copolymers via a tandem polymerization/cyclopolymerization strategy. J. Am. Chem. Soc. 2000,122, 10490-10491. 

Long-chain branched polyethylenes can be also obtained by copolymerization of ethene with ethene oligomers by tandem polymerization in one step [100] or with ethene/propene oligomers in two steps [101]. In the latter case, polymers are obtained with crystalline polyethylene backbone chains and amorphic ethene/ propene copolymer side chains [102]. 

Keywords Multi-component polymerization Tandem polymerization Alkyne polymerization Aggregation-induced emission... 

Multicomponent Tandem Polymerization of Alkynes, Carbonyl Chloride, and Thiols. .. 35... 

Alkyne-based MCPs are rarely reported, despite the rich chemistry of alkynes. Compared with traditional polymers, polymers prepared from alkyne monomers generally contain a conjugated polymer backbone and hence possess optoelectronic properties, enabling advanced functionalities of the polymer materials. However, their rigid structure can lead to poor solubility and limit the exploration of efficient polymerization methods [20]. In this review, the most up-to-date progress in the development of alkyne-based MCPs is introduced, including MCPs of alkynes, aldehydes, and amines MCPs of alkynes, azides, and amines/alcohols and multicomponent tandem polymerization of alkynes, carbonyl chloride, and thiols. 

Scheme 9 Synthesis of thiophene-containing polymer P8 via three-component tandem polymerization of diyne Ic, dicarbonyl chloride 13, and ethyl 2-mercaptoacetate 14...

This work presents the first example of one-pot, multicomponent tandem polymerization for the preparation of heterocyclic-containing conjugated polymers. The process exhibits excellent efficiency, complete conversion, and good tolerance of stoichiometric imbalance, generating polymers with large M, good solubility, and multiple functionalities. 

With the success of this three-component tandem polymerization, we further explored such polymerization by changing the third component monomer from ethyl 2-mercaptoacetate 14 to a normal thiol 16. We aimed to extend the scope of the one-pot, two-step, three-component coupling-addition tandem polymerization... 

Multicomponent polymerization of alkynes, including tandem polymerization, provides an efficient approach for the synthesis of functional polymer materials with unique structures that are difficult to obtain using other synthetic methods. The MCPs based on alkyne monomers are still quite limited. Three types of reported MCPs of alkynes are reviewed MCPs of alkynes, aldehydes, and amines MCPs of alkynes, azides, and amines/alcohols and tandem polymerization of alkynes, carbonyl chloride, and thiols. These MCPs have overcome the limitations of MCPs such as strict stoichiometric balance, poor polymer solubility, and low M , of the products. This field is still in its infant stage and more comprehensive work is an urgent demand. Through such pioneering work, we hope to inspire research enthusiasm and accelerate the pace of development of efficient polymerizatiOTi approaches for synthesis of various polymer structures, and pave the way to novel functional polymer materials. 

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