Lok Bianca, Mueller Gunnar, Ganster Johannes, Erdmann Jens, Buettner Andrea, Denk Philipp
Fraunhofer Institute for Process Engineering and Packaging IVV, Giggenhauser Straße 35, 85354 Freising, Germany.
Chair of Aroma and Smell Research, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Henkestraße 9, 91054 Erlangen, Germany.
Polymers (Basel). 2022 Jan 5;14(1):206. doi: 10.3390/polym14010206.
The still-rising global demand for plastics warrants the substitution of non-renewable mineral oil-based resources with natural products as a decisive step towards sustainability. Lignin is one of the most abundant natural polymers and represents an ideal but hitherto highly underutilized raw material to replace petroleum-based resources. In particular, the use of lignin composites, especially polyolefin-lignin blends, is currently on the rise. In addition to specific mechanical property requirements, a challenge of implementing these alternative polymers is their heavy odor load. This is especially relevant for lignin, which exhibits an intrinsic odor that limits its use as an ingredient in blends intended for high quality applications. The present study addressed this issue by undertaking a systematic evaluation of the odor properties and constituent odorants of commercially available lignins and related high-density polyethylene (HDPE) blends. The potent odors of the investigated samples could be attributed to the presence of 71 individual odorous constituents that originated primarily from the structurally complex lignin. The majority of them was assignable to six main substance classes: carboxylic acids, aldehydes, phenols, furan compounds, alkylated 2-cyclopenten-1-ones, and sulfur compounds. The odors were strongly related to both the lignin raw materials and the different processes of their extraction, while the production of the blends had a lower but also significant influence. Especially the investigated soda lignin with - and -like odors was highly different in its odorant composition compared to lignins resulting from the sulfurous kraft process predominantly characterized by and odors. These observations highlight the importance of sufficient purification of the lignin raw material and the need for odor abatement procedures during the compounding process. The molecular elucidation of the odorants causing the strong odor represents an important procedure to develop odor reduction strategies.
全球对塑料的需求仍在上升，这使得用天然产品替代不可再生的矿物油基资源成为迈向可持续发展的关键一步。木质素是最丰富的天然聚合物之一，是替代石油基资源的理想但迄今未得到充分利用的原材料。特别是，木质素复合材料，尤其是聚烯烃-木质素共混物的使用目前正在增加。除了特定的机械性能要求外，应用这些替代聚合物的一个挑战是它们的气味负荷很重。这对于木质素尤为重要，因为木质素具有固有的气味，这限制了它作为用于高质量应用的共混物成分的用途。本研究通过对市售木质素和相关高密度聚乙烯（HDPE）共混物的气味特性和成分气味剂进行系统评估，解决了这个问题。所研究样品的强烈气味可归因于71种单独的气味成分的存在，这些成分主要来自结构复杂的木质素。其中大多数可归为六个主要物质类别：羧酸、醛、酚、呋喃化合物、烷基化2-环戊烯-1-酮和硫化合物。气味与木质素原料及其不同的提取过程密切相关，而共混物的生产影响较小但也很显著。特别是所研究的具有 和 气味的苏打木质素，其气味剂组成与主要具有 和 气味的亚硫酸盐牛皮纸工艺产生的木质素相比有很大不同。这些观察结果突出了木质素原料充分纯化的重要性以及在混合过程中减少气味程序的必要性。对导致强烈气味的气味剂进行分子解析是制定减少气味策略的重要步骤。
