Photochemical transformation of diketone dopants in polyester matrices: Effect of dopants concentration and polyester structure on changes in molecular characteristics and hydrolysis of the matrices
Photochemical transformation of diketone dopants in polyester matrices: Effect of dopants concentration and polyester structure on changes in molecular characteristics and hydrolysis of the matrices
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DOI：
10.1016/j.polymertesting.2020.106821
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发表时间：
2020-11-01
期刊：
影响因子：
5.1
通讯作者：
Mosnacek, Jaroslav
中科院分区：
文献类型：
--
作者：
Borska, Katarina;Kasak, Peter;Mosnacek, Jaroslav
报道了光活性二酮衍生物1，2-二苯基乙烷-1，2-二酮（benzil，BZ）和1，4-双（苯甲酰基羰基）苯（bisbenzil，BIS）的光化学转化及其对聚己内酯（PCL）和聚乳酸（PLA）基质分子特性和水解性能变化的影响。在0.2-7.5重量%的宽掺杂剂浓度范围内进行研究。通过FTIR光谱观察结构变化。FTIR光谱证明BZ的逐步转化为过氧化苯甲酰，在PCL的情况下，形成极性基团。在GPC迹线中观察到分子特性的变化。在空气气氛下，在λ> 400 nm处辐照掺杂的聚合物膜主要导致聚合物基质的降解。此外，PCL中的高掺杂剂浓度导致凝胶含量高达15%的部分交联结构。与PLA基质相比，掺杂剂的光化学转化对PCL基质有很大的影响。通过测定可浸提产物以及使用GPC研究了随后的水解过程。与未辐照的样品相比，辐照的PCL样品的水解显示出显着的水解加速。此外，随着掺杂剂浓度的增加，水解速率逐渐增加。PCL的交联和降解可通过掺杂剂的类型、掺杂剂的浓度和PCL辐照期间的光强度来调节。与此相反，光化学预处理没有观察到的影响，在调查条件下的PLA的水解。
Photochemical transformations of photoactive diketone derivatives, 1,2-diphenylethane-1,2-dione (benzil, BZ) and 1,4-bis(benzoylcarbonyl)benzene (bisbenzil, BIS), and the effects of their transformations on changes in the molecular characteristics and hydrolytic properties of poly(epsilon-caprolactone) (PCL) and polylactide (PLA) matrices are reported. Studies were performed in a broad dopant concentration range of 0.2-7.5 wt%. Structural changes were observed by FTIR spectroscopy. FTIR spectroscopy proved the progressive transformation of BZ to benzoyl peroxides and, in the case of PCL, the formation of polar groups. Changes in molecular characteristics were observed in GPC traces. Irradiation of the doped polymer films at A lambda > 400 nm under an air atmosphere resulted mainly in the degradation of the polymer matrices. Additionally, high dopant concentrations in PCL led to partially crosslinked structures with gel contents up to 15%. The photochemical transformation of dopants had a large impact on the PCL matrices compared to that of the PLA matrices. A subsequent hydrolysis process was investigated by determining the extractable products as well as using GPC. Hydrolysis of irradiated PCL samples showed a significant acceleration of hydrolysis compared to that of nonirradiated samples. Furthermore, the hydrolysis rate gradually increased with increasing dopant concentration. The PCL crosslinking and degradation is adjustable by the type of dopant, concentration of dopant and intensity of light during irradiation of PCL. In contrast, a photochemical pretreatment had no observable effect on the hydrolysis of PLA under the investigated conditions.