Hot-Air/Hot-Steam Process for the Production of Laccase-Mediator-System Bound Wood Fiber Insulation Boards
Hot-Air/Hot-Steam Process for the Production of Laccase-Mediator-System Bound Wood Fiber Insulation Boards
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DOI：
10.15376/biores.10.2.3541-3552
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发表时间：
2015-01-01
期刊：
影响因子：
1.5
通讯作者：
Kharazipour, Alireza
中科院分区：
文献类型：
--
作者：
Euring, Markus;Kirsch, Alexander;Kharazipour, Alireza
介绍了一种新的木纤维保温板硬化工艺。在干燥过程中，纤维通常与聚合物-二苯基甲烷-二异氰酸酯（pMDI）粘合，并使用蒸汽-空气混合物硬化为木纤维绝缘板。然而，蒸汽-空气工艺中达到的最高温度为100摄氏度，不可能使用pMDI以外的替代粘合剂来胶合木纤维隔热板。当与漆酶介体系统（LMS）作为天然粘合系统一起孵育时，由于化学木材组成，特别是木质素，需要超过120摄氏度的温度。在这种情况下，热空气/热蒸汽工艺为实现100摄氏度以上的温度提供了新的技术机会。在这项研究中，木纤维绝缘板与LMS胶合，与参考板与灭活的LMS，漆酶单独，和4%pMDI。然后，使用三种工艺中的一种硬化板：蒸汽-空气混合物，热空气和热空气/热蒸汽。通过热空气/热蒸汽工艺，可以达到远高于120摄氏度的温度。所有的保温板硬化使用热空气/热蒸汽过程中表现出更好的物理和技术性能比那些硬化蒸汽-空气混合物或热空气单独。其原因是加入蒸汽后温度突然升高，因为高温确保LMS活化的木纤维表面木质素完全塑化。结果，用LMS处理的绝缘板的物理技术性能，如内部粘结强度、压缩强度和短期吸水率与用4%pMDI处理的那些板相当。
In this study, a new technical process for hardening wood fiber insulation boards is introduced. During the dry-process, the fibers are usually glued with polymeric-diphenylmethane-diisocyanate (pMDI) and hardened to wood fiber insulation boards using a steam-air mixture. However, the maximum temperature reached in the steam-air process was 100 degrees C, and it was impossible to use an alternative binding agent for the gluing of the wood fiber insulation boards other than pMDI. When incubated with laccase-mediator-system (LMS) as a naturally based bonding system, temperatures of over 120 degrees C are required because of the chemical wood composition, especially the lignin. In this case, the hot-air/hot-steam process offers new technical opportunities for realizing temperatures above 100 degrees C. In this study, wood fiber insulation boards were glued with LMS, vs. reference boards with inactivated LMS, laccase alone, and 4% pMDI. Then, the boards were hardened using one of three processes: with steam-air mixture, with hot-air, and with hot-air/hot-steam. Through the hot-air/hot-steam process, temperatures of well over 120 degrees C were attainable. All the insulation boards hardened using the hot-air/hot-steam process showed better physical and technical properties than those hardened with steam-air mixture or hot-air alone. The reason for this is a sudden increase of temperature after the adding of steam because high temperatures insure that the LMS activated wood fiber surface lignins are completely plasticized. As a result the physical-technological properties such as internal bond strength, compression strength, and short term water absorption of insulation boards treated with LMS were comparable to those boards treated with 4% pMDI.