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
Poly( glycolic acid-lactic acid)( PGLA) threadembedding material was modified by chitosan coating which could improve the rigidity,hydrophilicity and moisture absorption of the material,and produced better stimulation...Poly( glycolic acid-lactic acid)( PGLA) threadembedding material was modified by chitosan coating which could improve the rigidity,hydrophilicity and moisture absorption of the material,and produced better stimulation effect. Thus,this kind of thread-embedding materials which can be buried into acupuncture points to produce a long-time stimulation is popular in the acupuncture and moxibustion therapies. The variation tendencies of diameter,weight, hydrophilicity, and flexibility of the samples under the change of chitosan coating concentration,coating time and coating times were studied respectively. The results showed that the hydrophilicity,weight,and rigidity after coating rose in a certain range with the increase of coating time,coating times and coating concentration. The coating time had little influence on the diameter of fiber.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.
基金Biomedical Textile Materials Science and Technology(111 Project),China(No.B07024)
文摘Poly( glycolic acid-lactic acid)( PGLA) threadembedding material was modified by chitosan coating which could improve the rigidity,hydrophilicity and moisture absorption of the material,and produced better stimulation effect. Thus,this kind of thread-embedding materials which can be buried into acupuncture points to produce a long-time stimulation is popular in the acupuncture and moxibustion therapies. The variation tendencies of diameter,weight, hydrophilicity, and flexibility of the samples under the change of chitosan coating concentration,coating time and coating times were studied respectively. The results showed that the hydrophilicity,weight,and rigidity after coating rose in a certain range with the increase of coating time,coating times and coating concentration. The coating time had little influence on the diameter of fiber.
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。
