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4 results about "Living anionic polymerization" patented technology
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Living anionic polymerization is a living polymerization technique involving an anionic propagating species. Living anionic polymerization was demonstrated by Szwarc and co workers in 1956. Their initial work was based on the polymerization of styrene and dienes. One of the remarkable features of living anionic polymerization is that the mechanism involves no formal termination step. In the absence of impurities, the carbanion would still be active and capable of adding another monomer. The chains will remain active indefinitely unless there is inadvertent or deliberate termination or chain transfer. This gave rise to two important consequences: The number average molecular weight, Mₙ, of the polymer resulting from such a system could be calculated by the amount of consumed monomer and the initiator used for the polymerization, as the degree of polymerization would be the ratio of the moles of the monomer consumed to the moles of the initiator added. , where Mₒ = formula weight of the repeating unit, [M]ₒ = initial concentration of the monomer, and [I] = concentration of the initiator. All the chains are initiated at roughly the same time.
Active anionic polymerization initiation system based on alkyl magnesium reagent and polymerization method
The invention discloses an alkyl magnesium reagent-based active anionic polymerization initiation system and a polymerization method, and belongs to the technical field of polymer synthesis. A novel initiation system based on an alkyl magnesium reagent is developed, controllable anionic polymerization of various electron-withdrawing monomers is realized by accurately regulating and controlling reaction conditions and alkyl magnesium substituent structures, and a series of magnesium polymers with controllable molecular weight distribution are successfully synthesized. The polymerization process shows typical living polymerization characteristics, the block copolymer with a regular structure is prepared through a sequential feeding strategy, modification of multiple functional end groups can be achieved, and a new technical approach is provided for designing and synthesizing high polymer materials with specific performance. A novel alkyl magnesium initiating system which is low in cost and easy to operate is provided for active anionic polymerization, the limitation of a traditional initiating system is broken through, the magnesium polymer with magnesium ions at the tail end is synthesized, a new technical path is provided for controllable preparation of high polymer materials, and important theoretical significance and wide industrial application prospects are achieved.
Owner:DALIAN UNIV OF TECH
Star-branched butyl rubber and a method for preparing the same
This invention provides a method for preparing star-shaped branched butyl rubber, comprising the following steps: A) Styrene and its derivatives, a nitrogen-lithium initiator, a polarity modifier, and a solvent are mixed and reacted, and then butadiene is added to continue the reaction to obtain an SBS branching agent; B) SBS is catalytically hydrogenated, controlling the degree of hydrogenation to 20%~70%, to obtain a partially hydrogenated SBS branching agent; C) The partially hydrogenated SBS branching agent is dissolved in a solvent, mixed with isobutylene and isoprene, and an initiator is added to carry out a polymerization reaction to obtain the desired product. This invention uses living anionic polymerization technology to prepare block copolymers of styrene and its derivatives with butadiene, and partially hydrogenates them through catalytic hydrogenation. By controlling the catalyst / polarity modifier ratio, a branching agent with a specific degree of hydrogenation is synthesized. Then, the branching agent is dissolved in dichloromethane for the preparation of butyl rubber, resulting in star-shaped branched butyl rubber with a bimodal broad molecular weight distribution.
Owner:SHANDONG CHAMBROAD SINOPOLY NEW MATERIAL CO LTD
Synthesis of a positive chemical amplification photoresist resin, and preparation method and application thereof
This invention provides a positive chemical amplification photoresist resin synthesis method and its application. The positive chemical amplification photoresist resin has a specific structure, and its synthesis method involves obtaining a polymer with the corresponding structure through active anionic polymerization. This resin can improve problems such as tilted sidewalls and low resolution in photoresist after development, thereby meeting higher photolithography requirements.
Owner:WANHUA CHEM GRP CO LTD
A method for efficient polymer chain end functionalization based on carbon-magnesium / carbon-zinc bond and its application
This invention relates to a highly efficient polymer chain-end functionalization method based on carbon-magnesium / carbon-zinc bonds and its applications, belonging to the field of polymer synthesis technology. Step 1: Using living anionic polymerization, a polymer precursor with carbon-lithium or carbon-sodium bonds at the chain ends is synthesized. Step 2: Alkyl magnesium halide or alkyl zinc halide is added to the polymer precursor, causing a metal transfer reaction between the carbon-lithium or carbon-sodium bonds at the polymer precursor ends and the alkyl magnesium halide or alkyl zinc halide, yielding a polymer solution with C-Mg / C-Zn bonds at the ends. Step 3: The polymer is reacted with a specific end-capping agent to precisely introduce functional groups at the chain ends, achieving mild, efficient, and controllable end-group functionalization modification of the polymer. This invention can generate well-defined and relatively stable C-Mg or C-Zn bonds in situ at the polymer chain ends. The C-Mg / C-Zn bonds exhibit significantly enhanced resistance to air and moisture. By precisely controlling the reaction conditions and introducing a specific end-capping agent, highly efficient functionalization of the polymer chain ends can be achieved under mild conditions.
Owner:DALIAN UNIV OF TECH