Synthesis, Structure, and Property of Well-Defined Polymethylene-Based Diblock Copolymers by a Combination of Living Polymerization of Ylides and Atom Transfer Radical Polymerization

摘要

A combination of living polymerization of ylides and atom transfer radical polymerization (ATRP) was used successfully in the design and synthesis of well-defined polymethylene-b-poly(methyl methacrylate) (PM-b-PMMA) and polymethylene-b-poly(n-butyl acrylate) (PM-b-Pn-BuA). Tripolymethylene borane were firstly synthesized by living polymerization of dimethylsulfoxonium methylides and then oxidated quantitatively through trimethylamine-N-oxide dihydrate to provide a series of low-polydispersity hydroxyl-terminated polymethylenes (PM-OHs) with different molecular weight. Subsequently, such polymers were converted into polymethylene-based macroinitiators (PM-MIs, M-n(GPC) = 1900-10,400 g/mol; M-w/M-n = 1.12-1.23) in similar to 100% conversion. ATRPs of methyl methacrylate and n-butyl acrylate were successfully conducted using PM-MI to produce well-defined diblock copolymers of PM-b-PMMA and PM-b-Pn-BuA, respectively. The GPC traces indicated the successful extension of PMMA and Pn-BuA segment (M-n(GPC) of PM-b-PMMA = 3980-10,100 g/mol; M-w/M-n = 1.16-1.22; M-n of PM-b-Pn-BuA = 7400-9200 g/mol; M-w/M-n = 1.14-1.18). Atomic force microscopy (AFM) was used to characterize the structures of the precipitated PM-b-PMMA micelles, which were formed in toluene. The blend of LDPE/PMMA was prepared with PM-b-PMMA as compatibilizer. The scanning electron microscopy (SEM) results showed that the compatibilization of the LDPE/PMMA was improved greatly by the incorporation of PM-b-PMMA.