Structure and properties of bioabsorbable polyglycolide (PGA) and poly(glycolide-co-lactide) (PGA-co-PLA)fibers were investigated during several industrial processing stages and in vitro degradation by means of wide-a...Structure and properties of bioabsorbable polyglycolide (PGA) and poly(glycolide-co-lactide) (PGA-co-PLA)fibers were investigated during several industrial processing stages and in vitro degradation by means of wide-angle X-raydiffraction (WAXD), dynamic mechanical analysis (DMA) and mechanical property tests. In the orientation stage, the PGAfibers were found to have higher degrees of crystallinity than corresponding PGA-co-PLA samples produced under similarconditions. In the hot-stretching and post-annealing stages, after fibers were braided, PGA samples were found to gain morecrystallinity and higher T_g than PGA-co-PLA samples. The higher crystallinity in PGA fibers resulted in a slower rate ofdegradation. DMA results showed that a great deal of internal stress that was built during orientation and hot-stretchingstages was released in the post-annealing stage for a1l PGA and PGA-co-PLA samples. During earlier stages of in vitrodegradation, both PGA and PGA-co-PLA samples exhibited the typical cleavage-induced crystallization mechanism. Theheat shrinkage in the glass transition area was found to disappear after 6-8 days of degradation for all PGA and PGA-co-PLAsamples, indicating the amorphous portions of the polymers lost orientation after a short period in the buffer solution, mostlikely due to relaxation of the cleaved chains.展开更多
聚乙交酯丙交酯类共聚物(PGLA)聚合工艺中,催化剂多采用锡基催化剂,过量的残留锡(Sn)会对人体造成生物毒害。因此,为有效监控聚合工艺中生产物料的Sn含量,需要建立一套准确并快速的检测方法。通过优化微波消解条件和配方,并配合电感耦...聚乙交酯丙交酯类共聚物(PGLA)聚合工艺中,催化剂多采用锡基催化剂,过量的残留锡(Sn)会对人体造成生物毒害。因此,为有效监控聚合工艺中生产物料的Sn含量,需要建立一套准确并快速的检测方法。通过优化微波消解条件和配方,并配合电感耦合等离子体发射光谱(ICP-OES)法,建立了可用于测定PGLA产品中Sn含量的分析方法。称取0.10 g PGLA试样,以7 mL 65%~68%硝酸(HNO3)为消解液,消解温度最高为220℃。采用内标法进行定性定量分析,样品重复度好,RSD为3.65%。加标回收率在112%~115%,满足PGLA试样中的Sn含量分析需求,为工艺优化和产品质量控制提供了一种简单、实用的分析方法。展开更多
基金This research was made possible by a Johnson & Johnson CORD Internship Award funded by Ethicon. BH and BF thank the National Science Foundation for partial financial support (DMR-0098104).
文摘Structure and properties of bioabsorbable polyglycolide (PGA) and poly(glycolide-co-lactide) (PGA-co-PLA)fibers were investigated during several industrial processing stages and in vitro degradation by means of wide-angle X-raydiffraction (WAXD), dynamic mechanical analysis (DMA) and mechanical property tests. In the orientation stage, the PGAfibers were found to have higher degrees of crystallinity than corresponding PGA-co-PLA samples produced under similarconditions. In the hot-stretching and post-annealing stages, after fibers were braided, PGA samples were found to gain morecrystallinity and higher T_g than PGA-co-PLA samples. The higher crystallinity in PGA fibers resulted in a slower rate ofdegradation. DMA results showed that a great deal of internal stress that was built during orientation and hot-stretchingstages was released in the post-annealing stage for a1l PGA and PGA-co-PLA samples. During earlier stages of in vitrodegradation, both PGA and PGA-co-PLA samples exhibited the typical cleavage-induced crystallization mechanism. Theheat shrinkage in the glass transition area was found to disappear after 6-8 days of degradation for all PGA and PGA-co-PLAsamples, indicating the amorphous portions of the polymers lost orientation after a short period in the buffer solution, mostlikely due to relaxation of the cleaved chains.
文摘聚乙交酯丙交酯类共聚物(PGLA)聚合工艺中,催化剂多采用锡基催化剂,过量的残留锡(Sn)会对人体造成生物毒害。因此,为有效监控聚合工艺中生产物料的Sn含量,需要建立一套准确并快速的检测方法。通过优化微波消解条件和配方,并配合电感耦合等离子体发射光谱(ICP-OES)法,建立了可用于测定PGLA产品中Sn含量的分析方法。称取0.10 g PGLA试样,以7 mL 65%~68%硝酸(HNO3)为消解液,消解温度最高为220℃。采用内标法进行定性定量分析,样品重复度好,RSD为3.65%。加标回收率在112%~115%,满足PGLA试样中的Sn含量分析需求,为工艺优化和产品质量控制提供了一种简单、实用的分析方法。
