Functional polymer nanospheres prepared with reactive and biodegradable polymer surfactant

本研究的首要目标是合成一种反应性强、可生物降解的聚合物表面活性剂，并建立一种适用于用合成的表面活性剂进行多相聚合制备聚合物纳米球表面性质的控制技术。得到了以下结果：1.我们成功地合成了具有自由基聚合潜力的部分含乙烯基苄基的聚天冬氨酸反应性和生物降解性聚合物表面活性剂。用合成的聚合物表面活性剂与苯乙烯进行乳液共聚，制得了粒径为200~400 nm的稳定分散的聚合物纳米球。通过改变聚合过程中的配方，发现直径是可控的。从ζ-电位测量的角度来看，乳液共聚合制备的聚合物纳米球表面覆盖了聚天冬氨酸衍生物，其电势为-40 mV。这种高的z-电势被认为是由聚天冬氨酸大分子的羧基贡献的。以合成的聚天冬氨酸大分子单体为反应性分散剂，与苯乙烯进行分散共聚，通过乳液聚合得到较小的聚合物纳米球。所制备的聚合物纳米球的直径控制在35~150 nm之间。聚天冬氨酸大分子单体的浓度、乙烯基苄基的引入程度和主链的相对分子质量是影响制备的聚合物纳米球直径的重要参数。当合成的聚天冬氨酸大分子单体形成分子间缔合时，聚天冬氨酸大分子单体进行均聚反应以制备更小的纳米球。结果表明，形成了直径为10~30 nm的聚合物纳米球。通过苯乙烯与聚天冬氨酸衍生的反应性、可生物降解的聚合物表面活性剂的非均相共聚，成功地控制了直径在10~400 nm之间的聚合物纳米球。

The paramount objective of this research is to synthesize a reactive and biodegradable polymer surfactant and to establish the technique applicable to the control of surface properties of polymer nanospheres prepared by heterogeneous polymerization with the synthesized surfactant. The following results were obtained.l. We successfully synthesized the reactive and biodegradable polymer surfactant of polyaspartate partially bearing vinyl benzyl moiety which had a potential of radical polymerization.2. Emulsion copolymerization with styrene using the synthesized polymer surfactant provided stably-dispersed polymer nanospheres with a diameter of 200〜400 nm. The diameter was found to be controllable by changing a recipe in polymerization.3. Polymer nanospheres prepared by emulsion copolymerization was covered with polyaspartate derivative from a view point of ζ-potential measurement which was -40 mV. It was considered that this high z-potential was contributed to carboxyl group of polyaspartate macromer.4. Dispersion, copolymerization with styrene using the synthesized polyaspartate macromer as a reactive dispersant gave smaller polymer nanospheres by emulsion copolymerization. The diameter of the prepared polymer nanospheres was controlled between 35〜150 nm.5. The concentration of polyaspartate macromer, the introduction degree of vinyl benzyl moiety and the molecular weight of main chain were found to be significant parameters affected diameter of the prepared polymer nanospheres.6. As the synthesized polyaspartate macromonomer formed intermolecular association, homopolymerization of polyaspartate macromer was conducted to prepare much smaller nanospheres. The result was suggested the formation of polymer nanospheres with a diameter of 10〜30 nm.7. By heterogeneous copolymerzation of styrene with the reactive and biodegradable polymer surfactant derived from polyaspartate, we can successfully control a diameter of polymer nanospheres with a range between 10〜400 nm.