代写论文:可降解聚合物

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09/02/2018

代写论文:可降解聚合物

PCL的合成是通过环状单体 – 己内酯的聚合开环而发现的(Zhang等,2009)。使用催化剂如辛酸亚锡用于催化聚合,并已知具有用于控制聚合物分子量的低分子量醇。用于聚合PCL的机制有很多(Chao et al。2008)。这些是阴离子,配位和自由基离子。发现这些方法影响分子量,分子分布和端基组成​​(Wang等,2008)。 PCL被发现是一种半结晶聚合物。发现PCL化合物的平均分子量在3000-80000g / mol之间变化。 PCL可溶于室温下的四氯化碳,苯,环己烷(Hoskins and Grayson 2009)。也发现它们在丙酮,乙酸乙酯,乙腈中的溶解度较低(Boduch-Lee et al.2004)。发现它不溶于酒精或石油醚(Korich et al。2010)。 PCL与许多其他聚合物混合以抗裂(Li等,2014)。除此之外,粘合剂与其它聚合物如丙酸纤维素,聚乳酸,聚乳酸 – 共 – 乙醇酸组合使用以增加药物从微胶囊释放的吸收速率(Kim和Kim 2008)。 PCL与其他聚合物的这种相容性取决于输送系统的竞争渗透率的比例(Coulembier et al.2006)。 PCL的共聚物使用许多PVC,二甘醇,戊内酯单体(YongKweon等,2003)。许多可降解聚合物的物理和机械性能被使用并且已经被研究。

代写论文:可降解聚合物

The synthesize of the PCL is found by the ring-opening of the polymerization of the cyclic monomer- caprolactone ( Zhang et al. 2009). The use of catalysts such as stannous octoate is used to catalyze the polymerization and is known to have the low molecular weight alcohol which is used to control the molecular weight of the polymers. There are many mechanisms that are used for the polymerization of the PCL (Chao et al. 2008). These are the anionic, co-ordination and radical ions. The methods are found to affect the molecular weight, distribution of the molecules and the end group composition (Wang et al. 2008). The PCL is found to be a semi-crystalline polymer. The average molecular weight of the PCL compound is found to vary between 3000 to 80000 g/mol. The PCL is soluble in the carbon tetrachloride, benzene, cyclohexane in room temperature (Hoskins and Grayson 2009). They are also found to have lower solubility in the acetone, ethyl acetate, acetonitrile (Boduch-Lee et al. 2004). It is found to be insoluble in alcohol or petroleum ether (Korich et al. 2010). PCL is blended with a number of other polymers to crack resistance (Li et al. 2014). Apart from this, the adhesion is used in the combination with the other polymers such as cellulose propionate, polylactic acid, polylactic acid-co-glycolic acid to increase the rate of absorption of the drug release from the microcapsules (Kim and Kim 2008). This compatibility of the PCL with the other polymers depends on the ratio of the permeability of the delivery systems in contention (Coulembier et al. 2006). Copolymers of the PCL is developed using many of the monomers of PVC, diglycolide, valerlactone to name a few (YongKweon et al. 2003). The physical and the mechanical properties of many of the degradable polymers are used and have been investigated.