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Enabling synthesis toward the production of biocompatible magnetic nanoparticles with tailored surface properties.

机译：实现合成，以生产具有定制表面特性的生物相容性磁性纳米颗粒。

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Amphiphilic tri- and penta-block copolymers containing a polyurethane central block with pendant carboxylic acid groups flanked by hydroxyl functional polyether tails were synthesized. Our intention was to investigate the activities of these copolymers as dispersants for magnetite nanoparticles in biological media. A benzyl alkoxide initiator was utilized to prepare poly(ethylene oxide) (BzO-PEO-OH), poly(propylene oxide) (BzO-PPO-OH) and poly(ethylene oxide-b-propylene oxide) (poly(BzO-EO-b-PO-OH)) oligomeric tail blocks with varying lengths of PEO and PPO. The oligomers had a hydroxyl group at the terminal chain end and a benzyl-protected hydroxyl group at the initiated end. The polyether oligomers were incorporated into a block copolymer with a short polyurethane segment having approximately three carboxylic acid groups per chain. The block co-polyurethane was then hydrogenated to remove the benzyl group and yield primary hydroxyl functionality at the chain ends. End group analysis by 1H NMR showed the targeted ratio of PEO to PPO demonstrating control over block copolymer composition. Number average molecular weights determined by both 1H NMR and GPC were in agreement and close to targeted values demonstrating control over molecular weight. Titrations of the pentablock copolymers showed that the targeted value of approximately three carboxylic acid groups per chain was achieved.; Heterobifunctional poly(ethylene oxide) (PEO) and poly(ethylene oxide-b-propylene oxide) (PEO-b-PPO) copolymers were synthesized utilizing heterobifunctional initiators to yield polymers having a hydroxyl group at one chain end and additional moieties at the other chain end. For PEO homopolymers, these moieties include maleimide, vinylsilane, and carboxylic acid functional groups. Heterobifunctional PEO oligomers with a maliemide end group were synthesized utilizing a double metal cyanide coordination catalyst to avoid side reactions that occur with a basic catalyst. PEO oligomers with vinylsilane end groups were synthesized via alkoxide-initiated living ring-opening polymerization, and this produced polymers with narrow molecular weight distributions. Heterobifunctional PEO-b-PPO block copolymers were synthesized in two steps where the double metal cyanide catalyst was used to polymerize propylene oxide (PO) initiated by 3-hydroxypropyltrivinylsilane. The PPO was then utilized as a macroinitiator to polymerize ethylene oxide (EO) with base catalysis. Heterobifunctional PEO and PEO-b-PPO block copolymers possessing carboxylic acid functional groups on one end were synthesized by reacting the vinyl groups with mercaptoacetic acid via an ene-thiol addition.
机译：合成了两性三嵌段和五嵌段共聚物，该共聚物包含具有侧链羧酸基团的聚氨酯中心嵌段和侧接羟基官能聚醚尾部的聚氨酯。我们的目的是研究这些共聚物作为生物介质中磁铁矿纳米颗粒分散剂的活性。利用苄基醇盐引发剂制备聚环氧乙烷（BzO-PEO-OH），聚环氧丙烷（BzO-PPO-OH）和聚环氧乙烷-b-环氧丙烷（poly（BzO-EO -b-PO-OH）），具有不同长度的PEO和PPO的低聚尾嵌段。所述低聚物在末端链末端具有羟基，并且在起始末端具有苄基保护的羟基。将聚醚低聚物掺入具有短聚氨酯链段的嵌段共聚物中，该聚氨酯链段每链具有大约三个羧酸基团。然后将嵌段共聚聚氨酯氢化以除去苄基并在链端产生伯羟基官能团。通过1 H NMR进行的端基分析表明，PEO与PPO的目标比例表明对嵌段共聚物组成的控制。通过1 H NMR和GPC测定的数均分子量是一致的并且接近目标值，表明对分子量的控制。五嵌段共聚物的滴定表明，每链约达到三个羧酸基的目标值。利用杂双功能引发剂合成杂双功能聚环氧乙烷（PEO）和聚环氧乙烷-b-环氧丙烷（PEO-b-PPO）共聚物，以产生在一个链端具有羟基且在另一链具有附加部分的聚合物链端。对于PEO均聚物，这些部分包括马来酰亚胺，乙烯基硅烷和羧酸官能团。利用双金属氰化物配位催化剂合成了具有丙二酰亚胺端基的异双功能PEO低聚物，以避免与碱性催化剂发生副反应。通过醇盐引发的活性开环聚合反应合成了具有乙烯基硅烷端基的PEO低聚物，这产生了分子量分布窄的聚合物。分两步合成异双功能PEO-b-PPO嵌段共聚物，其中双金属氰化物催化剂用于聚合由3-羟丙基三乙烯基硅烷引发的环氧丙烷（PO）。然后将PPO用作大分子引发剂，在碱催化下聚合环氧乙烷（EO）。通过使乙烯基与巯基乙酸通过烯-硫醇加成反应而合成在一端具有羧酸官能团的杂双官能PEO和PEO-b-PPO嵌段共聚物。

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