排序方式: 共有4条查询结果,搜索用时 15 毫秒
1
1.
通过检测缝线的力学性能、分子量、失重、大分子取向和结晶度变化研究了聚二氧杂环己酮可吸收缝合线(PDS)在体外的初期(4星期)降解过程。研究结果表明,本文工艺条件下研制的PDS缝线在体外降解过程中随着分子量和大分子取向程度下降,力学性能明显下降,4星期时强度基本消失。分子量明显下降而失重变化很小的结果,证明PDS缝线的酯水解在链中和链端等活性,水解的几率只与水分子的可及程度相关。WAXD和DSC测试结果表明,随着体外降解进行,缝线原晶区基本保持不变,无定形区产生新的有序区,并且含量不断增加和完善。采用结晶高聚物微原纤结构模型解释PDS缝线无定形区在水中的降解机理与研究结果相吻合。PDS缝线的体外降解机理与聚羟基乙酸(PGA)缝线基本相同 相似文献
2.
3.
The mobility of polymer chain segments is shown to play a major role in the diffusion ofdisperse dyes in a copolymerization modified PET system, monoepoxy compoundCH_3 (CH_3),OCH_2CH--CH_2 modified PET. The rate of dye diffusion (diffusion coefficient D) hasbeen related to the time-dependent mechanical property, dynamic loss modulus E", which iscontrolled by the mobility of chain segments. In this modified copolyester system, the variance ofamount of modifier in the copolyester fibers causes the change in disperse dye diffusion coefficientto fiber, and in the dynamic loss modulus of the fibers, but the relationship between the diffusionand the dynamic loss modulus is in agreement with the theoretical relation derived by Bell andDumbleton. The relation obtained in this paper is:Ln D=-2. 28Ln E"+26. 81 相似文献
4.
1