Introducing polar biomass groups into polyolefins can not only improve their nonpolar nature but also conform to the concept of sustainable development. Now, an efficient route to generate polar functionalized polyolefins with high biomass content is reported. Two kinds of bioresourced comonomers are designed by assembling biomass groups (oleyl and cinnamyl groups) with the norbornene structure and inserted into the polyolefins by phosphine-sulfonate palladium-catalyzed copolymerization reactions. The norbornene spacer in the comonomers leads to great ethylene copolymerization results of catalytic activities (3.3 × 10 5 to 2.04 × 10 6 g mol −1 h −1 ), polymer molecular weights (68,000−188,000 g mol −1 ), and comonomer incorporations (1.9−22.4 mol %). Meanwhile, the insertions of these comonomers can easily tune the various properties of polyolefin materials, such as thermal, mechanic, surface, and optical properties. Furthermore, the deliberately introduced internal carbon−carbon double bonds in the biomass groups provide further reactive sites for sulfur vulcanization to enhance the tensile strength of copolymers. Two kinds of reversible dynamic cross-linked networks can also be built based on these carbon−carbon double bonds and endow the obtained polymers with good remodeling performances.
Heterogenization of homogeneous metal catalysts on solid
supports
has been widely studied for product morphology control in ethylene
polymerization. In this contribution, an emulsion polymerization strategy
was introduced to achieve heterogenization of various imino-based
nickel olefin polymerization catalysts. A series of polymeric microspheres
were prepared through emulsion copolymerization of vinyl-functionalized
imino ligands with comonomers such as styrene or methyl methacrylate.
The corresponding heterogeneous nickel catalysts demonstrated superior
properties in ethylene polymerization and copolymerization with methyl
10-undecylenate. Their catalytic properties can be controlled by tuning
the comonomer type, composition, and particle size. Most importantly,
this strategy can achieve product morphology control and avoid reactor
fouling while generating polyethylene products with minimum inorganic
contamination. In addition, the introduction of polymer microspheres
can improve the mechanical properties and surface properties of polyolefin
products.
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