Tree bark, an under-utilized forest residue, is renewable, abundant, and inexpensive; however, biorefinery of whole bark components for advanced utilizations is rather limited due to bark's inherently refractory characteristics: high integrity, complex composition, and high heterogeneity. Herein, we report an effective strategy to directly liquefy crude bark particles into a homogeneous bark oil while chain-extending through the originally inert bark hydroxyl groups to achieve an “OH-activated” state. These activated hydroxyl groups were then epoxidized and carbonated, accompanied by a chemical fixation of CO₂ at 15.7 wt% in the resulting cyclic carbonate product. The hereby synthesized carbonate was used as a precursor to prepare non-isocyanate polyurethanes (NIPUs), which showed a wide range of mechanical properties depending on the type of amine-based crosslinker selected. The ability of tuning NIPUs to achieve targeted mechanical properties makes these NIPUs applicable for various industrial applications. The novel synthetic approach developed in this study has great potential to allow us to fully utilize waste bark biomass to produce valued-added environmentally friendly products with higher sustainability.

中文翻译：

---

“吠叫”正确的树：从废料流到环状碳酸酯的生物精炼厂，其中二氧化碳固定化了非异氰酸酯聚氨酯

树皮是一种未被充分利用的森林残留物，可再生，丰富且廉价。然而，由于树皮固有的耐火特性：高完整性，复杂的组成和高度的异质性，整个树皮成分的生物精炼用于高级用途的能力相当有限。在本文中，我们报告了一种有效的策略，可直接将粗制树皮颗粒液化为均质的树皮油，同时通过最初呈惰性的树皮羟基进行扩链，以达到“ OH活化”状态。然后将这些活化的羟基环氧化和碳酸化，并伴随化学固定CO ₂在所得环状碳酸酯产物中的含量为15.7重量％。由此合成的碳酸盐用作制备非异氰酸酯聚氨酯（NIPU）的前体，该非异氰酸酯聚氨酯（NIPU）取决于选择的基于胺的交联剂的类型，具有广泛的机械性能。调整NIPU以获得目标机械性能的能力使这些NIPU适用于各种工业应用。这项研究中开发的新颖的合成方法具有巨大的潜力，使我们能够充分利用废弃的树皮生物质来生产具有更高可持续性的增值环保产品。