Pinkl Stefan, Veigel Stefan, Colson Jérôme, Gindl-Altmutter Wolfgang
Competence Centre for Wood Composites and Wood Chemistry, Wood K Plus, Linz 4040, Austria.
Department of Materials Science and Process Engineering, BOKU-University of Natural Resources and Life Sciences, Vienna 1180, Austria.
Polymers (Basel). 2017 Jul 31;9(8):326. doi: 10.3390/polym9080326.
The self-adhesive potential of nanocellulose from aqueous cellulosic suspensions is of interest with regard to a potential replacement of synthetic adhesives. In order to evaluate the performance of microfibrillated cellulose from different (ligno-)cellulosic raw materials for this purpose, softwood and hardwood powder were fibrillated and compared to sugar beet pulp as a representative non-wood cellulose resource, and conventional microfibrillated cellulose produced from bleached pulp. An alkali pre-treatment of woody and sugar beet raw materials enhanced the degree of fibrillation achieved, same as TEMPO-mediated oxidation of microfibrillated cellulose. Nanopapers produced from fibrillated material showed highly variable density and mechanical performance, demonstrating that properties may be tuned by the choice of raw material. While nanopaper strength was highest for TEMPO-oxidated microfibrillated cellulose, fibrillated untreated sugar beet pulp showed the best adhesive performance. Different microscopic methods (AFM, SEM, light microscopy) examined the interface between wood and fibrillated material, showing particular distinctions to commercial adhesives. It is proposed that fibrillated material suspensions, which achieve bond strength up to 60% of commercial urea-formaldehyde adhesive, may provide a viable solution to bio-based adhesives in certain applications where wet-strength is not an issue.
就合成粘合剂的潜在替代而言，来自水性纤维素悬浮液的纳米纤维素的自粘潜力备受关注。为了评估不同（含木质素的）纤维素原料的微纤化纤维素在此方面的性能，对软木粉和硬木粉进行了微纤化处理，并与作为代表性非木材纤维素资源的甜菜浆以及由漂白浆生产的传统微纤化纤维素进行了比较。对木质原料和甜菜原料进行碱预处理提高了微纤化程度，TEMPO介导的微纤化纤维素氧化也是如此。由微纤化材料制成的纳米纸显示出高度可变的密度和机械性能，表明可以通过选择原料来调整性能。虽然TEMPO氧化的微纤化纤维素制成的纳米纸强度最高，但未经处理的微纤化甜菜浆显示出最佳的粘合性能。不同的显微镜方法（原子力显微镜、扫描电子显微镜、光学显微镜）研究了木材与微纤化材料之间的界面，显示出与商业粘合剂的显著差异。有人提出，微纤化材料悬浮液在某些对湿强度无要求的应用中，可提供一种可行的生物基粘合剂解决方案，其粘结强度可达商业脲醛粘合剂的60%。
