Effects of supercritical carbon dioxide treatment on the morphology of poly(l-lactide)
Effects of supercritical carbon dioxide treatment on the morphology of poly(l-lactide)
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DOI：
10.1002/app.44006
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发表时间：
2016-10
影响因子：
3
通讯作者：
Chikara Tsutsumi;Ryouji Watanabe;Ayaka Tokumaru;Nao Kuwaoka;Y. Nakayama;T. Shiono
中科院分区：
文献类型：
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作者：
Chikara Tsutsumi;Ryouji Watanabe;Ayaka Tokumaru;Nao Kuwaoka;Y. Nakayama;T. Shiono
合成的L-丙交酯无规共聚物在超临界二氧化碳(SCCO_2)中制备时可用作控释材料，因为它们可通过水解进行生物降解。为了确定热性能对SCCO2加工后聚合物性能的影响，评估了三种具有不同性能的聚(L-丙交酯)。一个聚L丙交酯样品(H-100)的Tm在8-18 Mpa的加工压力范围内约为170C，而第二个样品(H-440)的Tm也显示出约152°C的恒定值。相反，聚(L-丙交酯)REVODE在加工前的Tm为146C，但在8 Mpa下处理后的Tm更高，为147C。与H-100和H-440不同，REVODE的TM值随着压力的增加而减小。在温度为40℃、压力为8 Mpa的温和条件下，样品的Tg值有较大提高，其中H-440和REVODE的Tg值分别提高了4℃和5℃。Tg值在12 Mpa时最低，随加工压力的增加而升高，但加工温度对Tg值的影响很小。H-100的Χ-c-DSC最初为18%，但在40℃和14 Mpa条件下经SCCO_2处理后增加到20%，并在较高的加工温度下进一步增加。尽管H-440的加工温度与Χc DSC值之间的关系显示出与H-100相同的趋势，但REVODE显示出不同的趋势。X射线衍射分析得到的Χc X射线衍射值与差示扫描量热法分析得到的值不同，并且显示出在80℃处理后的结晶度最大，无论是经过scCO2处理还是不处理。ATR FT-IR分析发现，即使在施加低温的情况下，经SCCO_2处理的聚(L-丙交酯)样品中的半结晶区域也有峰。©2016威利期刊公司J.应用。波兰姆。SCI。2016年，133,44006。
Synthetic l-lactide random copolymers can be employed as controlled release materials when prepared using supercritical carbon dioxide (scCO2), since they are biodegradable via hydrolysis. To determine the effects of thermal properties on polymer performance following scCO2 processing, three types of poly(l-lactide) having different properties were assessed. The Tm of one poly(l-lactide) sample (H-100) was found to be approximately 170 °C over the processing pressure range from 8 to 18 MPa, while a second sample (H-440) also showed a constant value of approximately 152 °C. In contrast, the poly(l-lactide) REVODE exhibited a Tm of 146 °C prior to processing but a higher value of 147 °C following treatment at 8 MPa. Unlike the H-100 and H-440, the Tm value of the REVODE tended to decrease with increasing pressure. The Tg values increased greatly under mild conditions of 8 MPa pressure and a temperature of 40 °C. In particular, the Tg values for the H-440 and REVODE increased by 4 °C and 5 °C, respectively. All Tg values were lowest at 12 MPa and increased with increasing processing pressure, although the effect of processing temperature was minimal. The Χc DSC of the H-100 was 18% initially but increased to 20% upon scCO2 processing at 40 °C and 14 MPa, and showed further increases at higher processing temperatures. Although the relationship between processing temperature and Χc DSC values for the H-440 showed the same trend as observed with the H-100, a different trend was seen for the REVODE. The Χc XRD values obtained from the XRD analyses differed from the values generated by DSC analysis, and showed a maximum degree of crystallinity following processing at 80 °C both with and without scCO2 treatment. ATR FT-IR analyses identified peaks due to semicrystalline regions in poly(l-lactide) samples treated with scCO2, even when applying low temperatures. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44006.