Grinins Juris, Biziks Vladimirs, Marais Brendan Nicholas, Rizikovs Janis, Militz Holger
Latvian State Institute of Wood Chemistry, 27 Dzerbenes Str., LV-1006 Riga, Latvia.
Georg-August University of Goettingen, Wood Biology and Wood Products, Büsgenweg 4, 437077 Göttingen, Germany.
Polymers (Basel). 2021 Jan 6;13(2):175. doi: 10.3390/polym13020175.
This study investigated the effect of phenol-formaldehyde (PF) resin treatment on the weathering stability and biological durability of birch plywood. Silver birch () veneers were vacuum-pressure impregnated with four different PF resins with average molecular weights (M) of 292 (resin A), 528 (resin B), 703 (resin C), and 884 g/mol (resin D). The aging properties of PF resin modified birch plywood were analyzed using artificial weathering with ultraviolet (UV) light, UV and water spray, and weathering under outdoor conditions. The same combinations of PF-treated plywood specimens were then tested in soil-bed tests to determine their resistance against soft-rot wood decay. It was not possible to compare weathering processes under artificial conditions to processes under outdoor conditions. However, the weathering stability of birch plywood treated with PF resins A, B, and C, scored better than plywood treated with commercial resin D (regardless of solid content concentration [%]). Results from unsterile soil bed tests showed improvements in resistance to soft-rot wood decay compared to untreated plywood and solid wood. Mass loss [%] was lowest for birch plywood specimens treated with resin of highest solid content concentration (resin D, 20%). Provisional durability ratings delivered durability class (DC) ratings of 2-3, considerably improved over untreated solid wood and untreated birch plywood (DC 5).
本研究调查了酚醛（PF）树脂处理对桦木胶合板耐候稳定性和生物耐久性的影响。白桦（）单板用四种不同的PF树脂进行真空压力浸渍，其平均分子量（M）分别为292（树脂A）、528（树脂B）、703（树脂C）和884 g/mol（树脂D）。采用紫外线（UV）人工老化、UV和喷水以及户外条件下的老化来分析PF树脂改性桦木胶合板的老化性能。然后对经过相同PF处理组合的胶合板试样进行土床试验，以确定其对软腐木材腐朽的抗性。无法将人工条件下的老化过程与户外条件下的过程进行比较。然而，用树脂A、B和C处理的桦木胶合板的耐候稳定性得分高于用商业树脂D处理的胶合板（无论固含量浓度 [%] 如何）。未灭菌土床试验的结果表明，与未处理的胶合板和实木相比，对软腐木材腐朽的抗性有所提高。固含量浓度最高的树脂（树脂D，20%）处理的桦木胶合板试样的质量损失 [%] 最低。暂定耐久性评级给出的耐久性等级（DC）为2 - 3级，相比未处理的实木和未处理的桦木胶合板（DC 5）有显著提高。
