Micro- and nanofibrillated cellulose (MNFC) was extracted from pineapple stems by acid hydrolysis, then characterized and tested in two concentrations (0.5 and 1.0 wt%) in polyvinyl acetate (PVAc) and urea-formaldehyde (UF) adhesives. The modified adhesives were used to glue three tropical wood species (Vochysia ferruginea, Cordia alliodora, and Gmelina arborea), and their corresponding bond strength resistance was determined. MNFC and the correspondent adhesives were characterized by TGA, FTIR, SEM, TEM, AFM, and viscosity determination. The TGA analysis of MNFC showed three decomposition reactions. The SEM, TEM, and AFM evaluations demonstrated the presence of micro- and nanosized dimensions of particles after the acid hydrolysis of pineapple stems. Adding 1 wt% MNFC to PVAc and UF adhesives increased their thermal stability in similar manner. Viscosity diminished in both modified adhesives with MNFC; however, this reduction did not affect the adhesion properties in the tropical wood tested. MNFC added to PVAc and UF adhesives improved shear strength (SS) of the glue line in the three tropical species tested. The highest SS increase was obtained when adding 0.5 wt% MNFC to PVAc in V. ferruginea, and 1 wt% MNFC concentration in the case of C. alliodora and G. arborea. In the case of UF adhesives, the application of 1 wt% MNFC produced significant differences in SS for the three tropical species studied.

中文翻译：

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菠萝（Ananas comosus）茎的微纤维和纳米原纤化纤维素（MNFC）及其在聚乙烯乙酸酯（PVAc）和脲醛（UF）木材胶粘剂中的应用

通过酸水解从菠萝茎中提取微纤维和纳米原纤化纤维素（MNFC），然后在聚乙酸乙烯酯（PVAc）和脲醛（UF）粘合剂中进行两种浓度（0.5和1.0 wt％）的表征和测试。修改后的粘合剂被用来粘合共有三个热带树种（Vochysia麻鸭，破布alliodora和石梓），并确定其相应的粘结强度。通过TGA，FTIR，SEM，TEM，AFM和粘度测定来表征MNFC和相应的粘合剂。MNFC的TGA分析显示出三个分解反应。SEM，TEM和AFM评估表明，菠萝茎酸水解后，存在微米级和纳米级的颗粒。向PVAc和UF粘合剂中添加1 wt％的MNFC以类似的方式提高了其热稳定性。两种含MNFC的改性胶粘剂的粘度均降低；但是，这种降低并不会影响所测试的热带木材的粘合性能。在三个测试的热带物种中，向PVAc和UF粘合剂中添加的MNFC改善了胶线的剪切强度（SS）。当向PVAc中添加0.5 wt％MNFC时，获得最高的SS增加。V. ferruginea和C. alliodora和G. arborea的MNFC浓度为1 wt％。对于超滤胶而言，对于三种研究的热带物种，使用1 wt％MNFC会导致SS的显着差异。