Bakhshi Hadi, Kuang Guanxing, Wieland Franziska, Meyer Wolfdietrich
Department of Life Science and Bioprocesses, Fraunhofer Institute for Applied Polymer Research IAP, Geiselbergstraße 69, 14476 Potsdam, Germany.
Department of Functional Polymer Systems, Fraunhofer Institute for Applied Polymer Research IAP, Geiselbergstraße 69, 14476 Potsdam, Germany.
Polymers (Basel). 2022 Jul 22;14(15):2974. doi: 10.3390/polym14152974.
In this study, photo-curing kinetics for urethane-acrylate-based photo-inks for 3D printing were evaluated using a photo-differential scanning calorimetry analysis. Initially, the photopolymerization kinetics of di- and monofunctional monomers were separately studied at different temperatures (5-85 °C). Later, the photo-curing kinetics and mechanical properties of photo-inks based on different monomer mixtures (40/60-20/80) were evaluated. The results showed that urethane-dimethacrylate (UrDMA) and urethane-acrylate (UrA) had no light absorption in the region of 280-700 nm, making them a proper crosslinker and a reactive diluent, respectively, for the formulation of 3D-printing photo-inks. The kinetics investigations showed a temperature dependency for the photo-curing of UrDMA, where a higher photopolymerization rate (: from 5.25 × 10 to 8.42 × 10 1/s) and double-bound conversion (: from 63.8% to 92.2%) were observed at elevated temperatures (5-85 °C), while the photo-curing of UrA was independent of the temperature (25-85 °C). Enhancing the UrA content from 60% to 80% in the UrDMA/UrA mixtures initially increased and later decreased the photopolymerization rate and conversion, where the mixtures of 30/70 and 25/75 presented the highest values. Meanwhile, increasing the UrA content led to lower glass transition temperatures () and mechanical strength for the photo-cured samples, where the mixture of 30/70 presented the highest maximum elongation (: 73%).
在本研究中，使用光差示扫描量热法分析评估了用于3D打印的聚氨酯丙烯酸酯基光油墨的光固化动力学。最初，在不同温度（5-85°C）下分别研究了双官能和单官能单体的光聚合动力学。随后，评估了基于不同单体混合物（40/60-20/80）的光油墨的光固化动力学和机械性能。结果表明，聚氨酯二甲基丙烯酸酯（UrDMA）和聚氨酯丙烯酸酯（UrA）在280-700nm区域没有光吸收，这使得它们分别成为用于配制3D打印光油墨的合适交联剂和活性稀释剂。动力学研究表明，UrDMA的光固化具有温度依赖性，在升高的温度（5-85°C）下观察到更高的光聚合速率（从5.25×10到8.42×10 1/s）和双键转化率（从63.8%到92.2%），而UrA的光固化与温度无关（25-85°C）。在UrDMA/UrA混合物中，将UrA含量从60%提高到80%，最初会提高然后降低光聚合速率和转化率，其中30/70和25/75的混合物呈现出最高值。同时，增加UrA含量会导致光固化样品的玻璃化转变温度（）和机械强度降低，其中30/70的混合物呈现出最高的最大伸长率（73%）。
