Nucleation Enhancement in Stereodefective Poly(L-lactide) by Free Volume Expansion Resulting from Low-Temperature Pressure CO2 Preconditioning
文献类型：期刊论文
| 作者 | Lan, Qiaofeng; Yu, Jian; Zhang, Jun; He, Jiasong |
| 刊名 | POLYMERS
 |
| 出版日期 | 2018-02-01 |
| 卷号 | 10期号:2页码:- |
| 英文摘要 | Nucleation enhancement in a highly stereodefective poly(L-lactide) (PLLA) with an optical purity of 88% by low-temperature pressure (0 and 35 degrees C under 2 MPa) CO2 preconditioning was investigated using differential scanning calorimetry (DSC), infrared (IR) spectroscopy, polarized optical microscopy (POM) as well as positron annihilation lifetime spectroscopy (PALS). Despite the preconditioning of the melt-quenched films for 2 h, IR results indicated that no trace of mesophase was generated and the samples remained in the glassy state. However, judging from the results of DSC, IR, and POM, when compared to the untreated sample, both the treated ones showed a significantly enhanced crystal nucleation effect, resulting in the corresponding greatly enhanced crystallization kinetics. Moreover, owing to the existence of the retrograde vitrification, the conditions of the previous low-pressure CO2 conditioning affected the nucleation enhancement effect. When compared to the case of 35 degrees C, the much lower temperature of 0 degrees C was more effective for nucleation enhancement. The PALS results indicated that the enlarged free volume, which resulted from the CO2 conditioning, largely accounted for the formation of locally ordered structures, providing many more potential nucleation sites for forming critical nuclei and thus the resulting enhanced crystallization kinetics in glassy PLLA. The present results have implications in understanding the nucleation enhancement effect, in particular in stereodefective PLLA systems, which possess extremely low crystallization ability and are thus probably too problematic to be evaluated by conventional methods. |
| WOS记录号 | WOS:000427542900015 |
| 源URL | [http://ir.iccas.ac.cn/handle/121111/38801]  |
| 专题 | 化学研究所_其它 |
| 推荐引用方式 GB/T 7714 | Lan, Qiaofeng,Yu, Jian,Zhang, Jun,et al. Nucleation Enhancement in Stereodefective Poly(L-lactide) by Free Volume Expansion Resulting from Low-Temperature Pressure CO2 Preconditioning[J]. POLYMERS,2018,10(2):-. |
| APA | Lan, Qiaofeng,Yu, Jian,Zhang, Jun,&He, Jiasong.(2018).Nucleation Enhancement in Stereodefective Poly(L-lactide) by Free Volume Expansion Resulting from Low-Temperature Pressure CO2 Preconditioning.POLYMERS,10(2),-. |
| MLA | Lan, Qiaofeng,et al."Nucleation Enhancement in Stereodefective Poly(L-lactide) by Free Volume Expansion Resulting from Low-Temperature Pressure CO2 Preconditioning".POLYMERS 10.2(2018):-. |
入库方式： OAI收割
来源：化学研究所
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