Fundamental Investigation of Novel Bark-Based Lignocellulosic Nanofibrils for Composite Applications

由于对化石燃料枯竭和气候变化的担忧，人们对利用可再生生物质材料生产环境友好产品的兴趣日益浓厚。树皮是锯木厂和纸浆造纸企业大量产生的一种废物，是一种宝贵的生物质来源，在该行业中只发现了几种低价值的用途。在过去的6年里，我们开发了从树皮中提取和转化多酚化合物的提取和转化技术，并用于制造树皮基胶粘剂、树脂和泡沫产品。然而，根据木材种类的不同，提取后仍有相当数量的固体残留物。为了充分发挥树皮生物炼油厂的潜力，必须利用所有树皮馏分，包括树皮提取残留物。建议的NSERC Discovery应用程序补充和扩展了我们过去在树皮生物精炼方面的工作，专注于对树皮提取残留物转化为具有高木素含量的树皮基木质纤维纳米纤维(BLNF)的纳米原纤化过程的基本了解。NSERC的这项建议将解决的具体研究目标是阐明：1)树皮微结构和木质素在BLNF纳米原纤化过程中的作用；2)干燥方法对BLNF结构、形态和表面拓扑化学的影响；3)BLNF在热固性和热塑性聚合物复合材料中作为增强材料的应用，以提高机械、热和阻隔性能。通过这些基础研究获得的机理见解将对实现真正的树皮生物精炼过程做出重大贡献，通过该过程，树皮材料的所有部分都被用于制造有价值的附加值产品。如果成功，树皮衍生的增值绿色化学品和含有BLNF的复合材料将减少市场对化石燃料衍生产品的依赖，并有助于将加拿大的森林磨坊转变为综合生物炼油厂，极大地提高林业部门在全球市场的竞争力。通过该项目培训的HQP将非常适合成为新兴生物经济的未来领导者，为加拿大的长期繁荣和福祉做出重大贡献。

There is a growing interest in utilizing renewable biomass materials to produce environmentally friendly products due to the concern for fossil fuel depletion and climate change. Bark, a waste stream produced in large quantities in saw mills and pulp and paper operations, is a valuable source of biomass that has found only a few low-valued usages in the industry. Over the last 6 years, we have developed extraction and conversion technologies for obtaining polyphenolic compounds from bark and to make value-added bark-based adhesives, resins, and foam products. However, depending on the wood species, a significant amount of solid residues still remain after the extraction. In order to realize the full potential of a bark biorefinery, utilization of all bark fractions, including the bark extraction residues, is necessary. The proposed NSERC Discovery application complements and extends our past work on bark biorefinery to focus on fundamental understanding of the nanofibrillation process of converting the bark extraction residues to highly promising novel bark-based lignocellulosic nanofibrils (BLNF) with a high lignin content. The specific research objectives that will be addressed by this NSERC proposal are to elucidate: 1) the role of bark microstructure and lignin on nanofibrillation processes of BLNF; 2) the effect of drying methods on structure, morphology, and surface topochemistry of BLNF; 3) the application of BLNF in thermoset and thermoplastic polymer composites as reinforcement for enhanced mechanical, thermal, and barrier performance. The mechanistic insights gained through these fundamental studies will contribute significantly to the realization of a true bark biorefinery process, by which all fractions of the bark materials are used for making valued added products. If successful, the bark-derived valued-added green chemicals and BLNF containing composites will reduce the market reliances on fossil fuel derived products and help transform Canadian forest mills into integrated biorefineries, greatly enhancing the forest sector's competitiveness in the global marketplace. HQP's trained by the project will be ideally suited to become the future leaders in the emerging bio-economy making significant contributions to Canada's long term prosperity and well-being.