Synthesis and characterization of synthetic polymer colloids colloidally stabilized by cationized starch oligomers

Abstract

A method is developed for anchoring enzymatically degraded cationized starch as electrosteric stabilizers onto synthetic latices, using cerium(IV) to create free‐radical grafting sites on the starch. Direct anchoring of debranched starch onto a poly(methyl methacrylate) seed latex yields a latex stabilized by well‐defined oligosaccharides. Using α‐amylase to randomly cleave starch to form (1→4)‐α‐glucans, and a comonomer, N‐isopropyl acrylamide (NIPAM), whose corresponding polymer exhibits a lower critical solution temperature (LCST), creates a means to synthesize block (or graft) oligomers of oligosaccharide and synthetic polymer, which are water soluble at room temperature. Above 30 °C, they become amphiphilic and form self‐emulsifying nanoparticles (sometimes termed “frozen micelles”) from which a synthetic latex is grown after addition of methyl methacrylate, the collapsed NIPAM‐containing entities functioning as a type of in situ seed. This synthesis of stable synthetic latex particles is shown to have a high grafting efficiency. The starch fragments were characterized by 1H solution‐state NMR before grafting, and 13C solid‐state cross‐polarization magic‐angle spinning (CP‐MAS) NMR was used to characterize the starch oligomers actually grafted on the final latex. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1836–1852, 2009

Preparation and characterization of oxidized starch-graft-poly(styrene-butyl acrylate) latex via emulsion polymerization

“…When the amount of OS is higher than 6 g, it is easy to form coagulum in the copolymerization. This may be due to the high molecular weight and long chain-length of the OS molecules [19].…”

On the Use of Starch in Emulsion Polymerizations

“…Debranched cationic starch was grafted to: (1) pre-synthesized and monomer swollen poly (MMA) particles (GE = 8.5%); (2) MMA monomer in an emulsion polymerization (GE = 24%), and; (3) MMA monomer in the presence of poly (N-isopropylacrylamide). The second feed strategy led to slow particle nucleation and hence a broad particle distribution and low GE [160].…”

“…The application of mixed monomer/starch batch seed generation, as well as the use of high shear mixing narrowed the particle size distribution (PSD) and improved the GE [137,160,189,190,208]. Semi-batch feeding of monomer or a pre-emulsion to achieve monomer starved conditions could be favourable for starch incorporation into latex particles, especially in the case where homopolymerization is a concern.…”

Maltodextrin as stabilizer for emulsion polymerization: Adsorption and grafting behavior

“…The same authors applied different strategies to form starch‐grafted polymers starting from a seed latex produced by conventional emulsion polymerization as well as to promote the grafting of the polysaccharides through a predegradation of the oligosaccharides. [ 21,22 ]…”