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Reversible addition-fragmentation chain transfer (RAFT) polymerization was adopted to synthesize starch-based conjugates that possessed controllable architecture and properties. Starch-based xanthate agent was prepared and applied as chain transfer agent to conduct the living/controlled polymerization (LCP) of vinyl acetate, which generated tailor-made conjugates of starch and well-defined poly(vinyl acetate) (SVAc). The relevant derivatives, conjugates of starch and chain length-controlled poly(vinyl alcohol) (SVA), were obtained subsequently. Various characterizations such as Fourier trans- form infrared spectra (FTIR), ultraviolet-visible spectroscopy (UV), proton nuclear magnetic resonance ( 1 H NMR), gel per- meation chromatography (GPC), X-ray diffraction (XRD), Thermogravimetric analysis (TGA), and dynamic mechanical thermal analysis (DMTA) were performed to examine the structure of intermediates and the starch-based conjugates. Static contact angle measurements revealed that the hydrophilic character of starch-based conjugates was tunable. Well-defined SVAc was amphiphilic and it was able to self-assemble into size controllable micelles, which was verified by contact angles, transmission electron microscopy (TEM) and dynamic light scattering (DLS) tests. SVA exhibited much higher capability to form physically cross-linked hydrogel than starch did. Both the characteristic of SVAc and SVA were chain length-dependent.

Starch is a natural polymer which possesses many unique properties and some shortcoming simultaneously. Some synthetic polymers are biodegradable and can be tailor-made easily. Therefore, by combining the individual advan- tages of starch and synthetic polymers, starch-based completely biodegradable polymers (SCBP) are potential for applica- tions in biomedical and environmental fields. Therefore it received great attention and was extensively investigated. In this paper, the structure and characteristics of starch and some synthetic degradable polymers are briefly introduced. Then, the recent progress about the preparation of SCBP via physical blending and chemical modification is reviewed and discussed. At last, some examples have been presented to elucidate that SCBP are promising materials for various applications and their development is a good solution for reducing the consumption of petroleum resources and environmental problem.