Balla Evangelia D, Klonos Panagiotis A, Kyritsis Apostolos, Bertoldo Monica, Guigo Nathanael, Bikiaris Dimitrios N
Laboratory of Polymer Chemistry and Technology, Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
Department of Physics, National Technical University of Athens, Zografou Campus, 15780 Athens, Greece.
Polymers (Basel). 2024 Aug 10;16(16):2270. doi: 10.3390/polym16162270.
The present work describes the synthesis of poly(butylene succinate) (PBSu)-cutin copolymers by the two-stage melt polycondensation method, esterification and polycondensation. Cutin was added in four different concentrations, 2.5, 5, 10, and 20 wt%, in respect to succinic acid. The obtained copolymers were studied using a variety of techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), polarized light microscopy (PLM), as well as diffuse reflectance spectroscopy (DRS). A series of results, in agreement between different techniques, revealed the formation of PBSu-cutin interactions, confirming indirectly the successful in situ synthetic route of copolymers. DSC and XRD combined with PLM results provided indications that the crystallization temperature increases with the addition of small amounts of cutin and gradually decreases with increasing concentration. The crystallization process was easier and faster at 2.5%, 5%, and 10% concentrations, whereas at 20%, it was comparable to neat PBSu. The presence of cutin, in general, leads to the facilitated crystallizability of PBSu (direct effect), whereas a moderate drop in the glass transition temperature is recorded, the latter being an indirect effect of cutin via crystallization. The thermal stability improved in the copolymers compared to neat PBSu. Water contact angle measurements confirmed that the addition of cutin decreased the hydrophilicity. The local and segmental relaxation mapping is demonstrated for PBSu/cutin here for the first time. Enzymatic hydrolysis and soil degradation tests showed that, overall, cutin accelerated the decomposition of the polymers. The copolymers may be proven useful in several applications.
本工作描述了通过两阶段熔融缩聚法（酯化和缩聚）合成聚丁二酸丁二醇酯（PBSu）-角质共聚物的过程。相对于丁二酸，角质以四种不同浓度（2.5、5、10和20 wt%）添加。使用多种技术对所得共聚物进行了研究，如傅里叶变换红外光谱（FTIR）、X射线衍射分析（XRD）、差示扫描量热法（DSC）、热重分析（TGA）、偏光显微镜（PLM）以及漫反射光谱（DRS）。一系列不同技术之间相互印证的结果揭示了PBSu-角质相互作用的形成，间接证实了共聚物原位合成路线的成功。DSC和XRD结合PLM结果表明，结晶温度随着少量角质的添加而升高，并随着浓度的增加逐渐降低。在2.5%、5%和10%的浓度下，结晶过程更容易、更快，而在20%时，与纯PBSu相当。一般来说，角质的存在导致PBSu的结晶性增强（直接效应），而玻璃化转变温度有适度下降，后者是角质通过结晶产生的间接效应。与纯PBSu相比，共聚物的热稳定性有所提高。水接触角测量证实，角质的添加降低了亲水性。本文首次展示了PBSu/角质的局部和链段弛豫图谱。酶水解和土壤降解试验表明，总体而言，角质加速了聚合物的分解。这些共聚物可能在多种应用中被证明是有用的。
