敏化剂从氟化二氧化硅表面的光释放是通过单线态氧与乙烯基醚键接头的反应以及二氧杂环丁烷中间体的断裂而发生的。对释放的敏化剂进行辐照会产生单线态氧,从而通过自催化反应加速更多敏化剂的释放。正丁醇和正辛醇中敏化剂释放的 Sigmoidal 行为发生在 20 °C 的最佳温度下。由于长寿命的二氧杂环丁烷和低效的断裂,光致剥离效率在低温下降低,其中敏化剂保留在表面上,并且在高温下也降低,因为1 O 2 的反应较慢与乙烯基醚键。立即加速是释放的敏化剂被用作掺杂剂以消除诱导步骤的结果,进一步暗示了自催化机制。然而,S形敏化剂的释放与溶剂粘度、热量或二氧杂环丁烷分解产生的光或氟化二氧化硅引起的O 2溶解度的轻微增强无关。此处收集的机理信息可用于帮助控制药物释放的速度;然而,基于自催化的药物递送系统是否比具有非 S 形动力学的药物递送系统具有优势还有待观察。
Understanding the efficacy of<i>N,N</i>-dimethylformamide and oxalyl chloride combination as chemoselective<i>O</i>-formylating agent: An unified experimental and theoretical study
efficient synthetic protocol for the O-formylation of a wide range of aromatic hydroxyl/phenolic substrates using an N,N-dimethylformamide (DMF) and oxalyl chloride [(COCl)2] combination in dichloromethane (DCM) as solvent at ambient temperature. The DMF/(COCl)2 combination was found to be highly chemoselective for the aromatic/phenolic hydroxyl group over aliphatic hydroxyl or aromatic amine/thiol
POLYCARBONATE-POLYESTER BLOCK COPOLYMER COMPOSITIONS, METHODS, AND ARTICLES
申请人:Mullen Brian
公开号:US20080300379A1
公开(公告)日:2008-12-04
A polycarbonate-polyester block copolymer includes a polycarbonate block and a polyester block, each having specific structures. The block copolymer can be prepared, at least in part, from renewable feedstocks. In some forms, the block copolymer includes biodegradable segments that facilitate structural breakdown of objects molded from the block copolymer. Methods of preparing the block copolymer are described as are- compositions that include it and articles prepared from it.
US7671169B2
申请人:——
公开号:US7671169B2
公开(公告)日:2010-03-02
[EN] POLYCARBONATE-POLYESTER BLOCK COPOLYMER COMPOSITIONS, METHODS, AND ARTICLES<br/>[FR] COMPOSITIONS DE COPOLYMÈRE SÉQUENCÉ POLY(CARBONATE)-POLY(ESTER), PROCÉDÉS ET ARTICLES
申请人:SABIC INNOVATIVE PLASTICS IP
公开号:WO2008150737A1
公开(公告)日:2008-12-11
[EN] A polycarbonate-polyester block copolymer includes a polycarbonate block and a polyester block, each having specific structures. The block copolymer can be prepared, at least in part, from renewable feedstocks. In some forms, the block copolymer includes biodegradable segments that facilitate structural breakdown of objects molded from the block copolymer. Methods of preparing the block copolymer are described, as are compositions that include it and articles prepared from it. [FR] L'invention concerne un copolymère séquencé poly(carbonate)-poly(ester) comprenant une séquence poly(carbonate) et une séquence poly(ester), ayant chacune des structures spécifiques. Le copolymère séquencé peut être préparé, au moins en partie, à partir de matières renouvelables. Dans certaines formes, le copolymère séquencé comprend des segments biodégradables qui facilitent la dissociation structurelle d'objets moulés à partir du copolymère séquencé. Des procédés de préparation du copolymère séquencé, ainsi que de compositions qui le comprennent et des articles préparés à partir de celui-ci sont décrits.