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含柔性链段聚右旋乳酸嵌段共聚物对聚左旋乳酸拉伸行为的影响 被引量:4
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作者 李晓露 王锐 +4 位作者 杨春芳 董振峰 张秀芹 王笃金 王德义 《高分子学报》 SCIE CAS CSCD 北大核心 2018年第5期598-606,共9页
采用聚右旋乳酸(PDLA)与聚乙二醇(PEG)的三嵌段共聚物(PDLA-b-PEG-b-PDLA)对聚左旋乳酸(PLLA)进行改性,系统研究熔融共混法制备的PLLA/PDLA-b-PEG-b-PDLA共混物的热性能和不同温度下的拉伸行为,并通过原位X射线散射(WAXS)技术探索不同... 采用聚右旋乳酸(PDLA)与聚乙二醇(PEG)的三嵌段共聚物(PDLA-b-PEG-b-PDLA)对聚左旋乳酸(PLLA)进行改性,系统研究熔融共混法制备的PLLA/PDLA-b-PEG-b-PDLA共混物的热性能和不同温度下的拉伸行为,并通过原位X射线散射(WAXS)技术探索不同含量的PDLA-b-PEG-b-PDLA对PLLA在拉伸过程中结晶行为的影响.结果表明,加入PDLA-b-PEG-b-PDLA对PLLA的热稳定性影响较小;PLLA/PDLA-b-PEG-b-PDLA共混物中由于立构晶的存在,能有效提高PLLA的α晶的结晶速率;室温(30°C)拉伸时,样品均呈现脆性断裂;拉伸温度提高至50°C,纯PLLA和PLLA/PDLA-b-PEG-b-PDLA(95/5)的共混物仍然呈现脆性断裂,但是随着PDLA-b-PEG-b-PDLA含量的增加,PLLA发生屈服,断裂伸长率由纯PLLA的10%左右提高至200%以上;80°C拉伸时,PDLA-b-PEG-b-PDLA的加入显著提高了PLLA在拉伸过程中的结晶速率,出现α晶的应变从纯PLLA的400%降低至50%以下,立构晶含量在拉伸过程中基本保持不变.上述结果显示含柔性链段的PDLA的嵌段共聚物可有效提高PLLA的结晶速率和延展性,拓宽PLLA的应用范围. 展开更多
关键词 聚左旋乳酸 嵌段共聚物 拉伸行为 结晶
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Evaluation of the osseointegration of dental implants coated with calcium carbonate:an animal study
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作者 yi Liu yi Zhou +3 位作者 Tao Jiang You-de Liang Zhen Zhang yi-Ning wang 《International Journal of Oral Science》 SCIE CAS CSCD 2017年第3期133-138,共6页
In an attempt to overcome the limitations of titanium in dental and orthopaedic clinical applications, a new method has been developed to prepare calcium carbonate coatings on sandblasted and acid-etched (SA) titani... In an attempt to overcome the limitations of titanium in dental and orthopaedic clinical applications, a new method has been developed to prepare calcium carbonate coatings on sandblasted and acid-etched (SA) titanium implants. The purpose of this study was to investigate the effect of calcium carbonate-SA (CC-SA) implants on osseointegration in vivo. The surfaces of SA and CC-SA implants were characterised for surface morphology and surface chemistry. Subsequently, these two kinds of implants were implanted in the femoral condyles of rabbits. The implants were retrieved and prepared for histological and histomorphometric evaluation 1, 2, 4, 8 and 12 weeks after implantation. Significantly higher values of bone-to-implant contact of the entire implant except the gap area (BIC_ALL) and the bone-to-implant contact of the gap area (BIC_GAP) were found in animals with the CC-SA implants than in those with the SA implants at 4 weeks. Higher values of total gap bone were found in those with the CC-SA implants than in those with the SA implants at 1, 2 and 4 weeks. In conclusion, the current findings demonstrate that the calcium carbonate coating can improve and accelerate the early ingrowth of bone and osseointegration at the early healine phase. This may reduce clinical healinE times and thus improve implant success rates. 展开更多
关键词 calcium carbonate HISTOMORPHOMETRY in vivo OSSEOINTEGRATION TITANIUM
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