Role of moisture in photo-ageing -macromolecular architecture evolution of acrylic-urethane network
Role of moisture in photo-ageing -macromolecular architecture evolution of acrylic-urethane network
复制标题
水分在光老化中的作用-丙烯酸-聚氨酯网络的大分子结构演化
DOI：
10.1016/j.polymertesting.2021.107123
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发表时间：
2021
期刊：
影响因子：
5.1
通讯作者：
Elakneswaran Yogarajah
中科院分区：
文献类型：
--
作者：
Ishida Takato;Kitagaki Ryoma;Hagihara Hideaki;Elakneswaran Yogarajah
在这项工作中，水分在光老化的作用进行了讨论的情况下，丙烯酸-聚氨酯网络。老化行为的特点是傅立叶变换红外光谱，正电子湮没寿命谱，溶胶-凝胶分析，和差示扫描量热法。干和湿光老化之间的两个共同特点，即，减少的平均自由体积和增加的玻璃化转变温度进行了观察，作为光氧化的进展。湿光老化样品的最终内部结构特征与干光老化样品的最终内部结构特征不同。尽管干光老化样品表明由于广泛的交联形成而导致网络致密化，但湿光老化导致不均匀的结构，其中交联之间的平均摩尔质量（在几纳米的尺度下）增加，并且一些域在亚纳米级交联。考虑到水引起的物理（塑化）和化学（水解）效应，提出了一种可能的机制，为大分子结构的演变在干燥和潮湿的环境中的光老化。
In this work, the role of moisture in photo-ageing was discussed for the case of an acrylic-urethane network. Ageing behaviours were characterised by Fourier transform infra-red spectroscopy, positron annihilation lifetime spectroscopy, sol-gel analysis, and differential scanning calorimetry. Two common features between dry and wet photo-ageing, namely, decrease in the mean free volume and increase in the glass transition temperature were observed as photo-oxidation progressed. The characteristics of the final internal structure of the wet photo-aged sample differed from those of the dry photo-aged sample. Although the dry photo-aged samples suggested network densification due to extensive crosslinking formation, wet photo-ageing led to an inhomogeneous structure wherein the average molar mass between crosslinks (at a scale of several nanometres) increased and some domains crosslinked at the sub-nanoscale. Considering the physical (plasticisation) and chemical (hydrolysis) effects induced by water, a possible mechanism for the evolution of the macromolecular architecture was proposed for photo-ageing in dry and wet environments.