Highly cis -1,4 Selective Living Polymerization of Unmasked Polar 2-(2-Methylidenebut-3-enyl)Furan and Diels-Alder Addition

Synthesis of Chain-End Functional Polydienes Using Diene Comonomer Bearing Boronic Acid Masked with Diaminonaphthalene

Diene comonomers bearing boronic acid masked with 1,8-diaminonaphthalene (dan) were applied to copolymerization with isoprene or butadiene using neodymium borohydride complex as a catalyst. The comonomers were tolerant to excess modified methylaluminoxane (MMAO) and thus were applicable to the polymerization system using MMAO. On the other hand, the corresponding pinacol borate was highly reactive toward MMAO, and no incorporation into the obtained polymer was observed. A ¹³C NMR microstructural analysis of the hydrogenated copolymer revealed that all of the comonomers were located at the chain end. Further functionalization using the boron moiety at the polymer chain end was also investigated.

Enzymatic and Chemical Approaches for Post-Polymerization Modifications of Diene Rubbers: Current state and Perspectives

Diene rubbers are polymeric materials which present elastic properties and have double bonds in the macromolecular backbone after the polymerization process. Post-polymerization modifications of rubbers can be conducted by enzymatic or chemical methods. Enzymes are environmentally friendly catalysts and with the increasing demand for rubber waste management, biodegradation and biomodifications have become hot topics of research. Some rubbers are renewable materials and are a source of organic molecules, and biodegradation can be conducted to obtain either oligomers or monomers. On the other hand, chemical modifications of rubbers by click-chemistry are important strategies for the creation and combination of new materials. In a way to expand the scope of uses to other non-traditional applications, several and effective modifications can be conducted with diene rubbers. Two groups of efficient tools, enzymatic, and chemical modifications in diene rubbers, are summarized in this review. By analyzing stereochemical and reactivity aspects, the authors also point to some applications perspectives for biodegradation products and to rational modifications of diene rubbers by combining both methodologies.

Access to Highly Stereodefined 1,4-cis-Polydienes by a [Ni/Mg] Orthogonal Tandem Catalytic Polymerization

A [Ni/Mg]-catalyzed orthogonal tandem polymerization has been developed starting from enol phosphates. Initial investigations conducted on branched 1,3-dienes as monomers enabled identification of a Mg-initiated polymerization process leading to 1,4-cis-polydienes. When aryl enol phosphates are used as monomers, the [Ni/Mg]-catalyzed tandem polymerization affords 1,4-cis-polydienes with selectivities up to 99%. Elastomeric or crystalline materials were obtained by simple structural modifications of the monomeric unit. This tandem approach appears as a straightforward and efficient way to enforce diversity and selectivity in diene polymerization while retaining a fair degree of control, just as observed for stepwise systems that are accessible through established time- and manpower-consuming synthetic procedures.

Cobalt catalysed controlled copolymerization: an efficient approach to bifunctional polyisoprene with enhanced properties

Bifunctional polyisoprene with controlled molecular weight was obtained by coordination insertion polymerization.

Synthesis and properties investigation of hydroxyl functionalized polyisoprene prepared by cobalt catalyzed co-polymerization of isoprene and hydroxylmyrcene

Controlled copolymerization of isoprene and hydroxylmyrcene afforded well-defined hydroxyl functionalized polyisoprene. Blends of functionalized polyisoprene/SiO₂ displayed enhanced miscibility, and remarkable vulcanization and mechanical properties.

Syndio-and cis-1,4 dually selective copolymerization of polar fluorostyrene and butadiene using rare-earth metal catalysts

Synthesizing functional butadiene–styrene rubber through coordination polymerization is a theoretical challenge for polymer science, since functional monomers usually deactivate to the applied catalysts.

In-chain functionalized syndiotactic 1,2-polybutadiene by a Ziegler–Natta iron(iii) catalytic system

Copolymerization of 1,3-butadiene with four 1-substituted 1,3-diene comonomers bearing amino and alkyoxy groups by a Ziegler–Natta iron(iii) catalytic system to access in-chain functionalized syndiotactic 1,2-polybutadiene is reported herein. The polar comonomer content can be easily regulated by varying the comonomer loadings or polymerization conditions, affording functionalized syndiotactic 1,2-polybutadiene with different amounts of functionalities. The incorporation of a polar comonomer showed little influence on the 1,2-content and stereoregularity of the resulting polymers, giving a 1,2-structure as high as ∼85% and an rrrr pentad of 81.0%. Significantly improved surface properties of the polymers was obtained after incorporation of polar comonomer, as revealed from the remarkably decreased water contact angles.

In-chain functionalized syndiotactic 1,2-polybutadiene through copolymerization of 1,3-butadiene and 1-substituted 1,3-diene comonomer by a Ziegler–Natta iron(iii) catalytic system.

Selectively creating oxygen vacancies on PrCe/SiO2 catalysts for the transformation of a furfural–acetone adduct into a functionalized 1,3-diene

Oxygen vacancies were selectively created on PrCe/SiO₂ for efficient transformation of a furfural–acetone adduct into a functionalized 1,3-diene.