ABSTRACT
Mechanochemical postpolymerization modification is reported herein. The fast and efficient synthesis of a library of macromolecules with functional diversity and structural uniformity was realized without a solvent by means of a high speed ball-milling technique. A series of polymers prepared from 4-vinylbenzaldehyde (4-VBA) underwent solid-state Schiff base formations with a series of amines and amine derivatives. The efficient mixing and energy delivery provided by the collisions between balls not only promoted rapid imine formation but also eliminated the need for a chemical solvent, which is highly desirable for green chemical synthesis.
ABSTRACT
Mechanochemical polymerization of lactide is carried out by using ball milling. Mechanical energy from collisions between the balls and the vessel efficiently promotes an organic-base-mediated metal- and solvent-free solid-state polymerization. Investigation of the parameters of the ball-milling synthesis revealed that the degree of lactide ring-opening polymerization could be modulated by the ball-milling time, vibration frequency, mass of the ball media, and liquid-assisted grinding. Liquid-assisted grinding was found to be an especially important factor for achieving a high degree of mechanochemical polymerization. Although polymer-chain scission from the strong collision energy prevented mechanical-force-driven high-molecular-weight polymer synthesis, the addition of only a small amount of liquid enabled sufficient energy dissipation and poly(lactic acid) was thereby obtained with a molecular weight of over 1×105 â g mol-1 .
