Enhancement of mechanical and flame-retardant properties  of Acacia hybrid through the treatment of a combination of styrene-acrylic copolymer and sodium silicate

Nguyen Thi Tham; Tran Cong Chi; Phan Duy Hung; Trinh Hien Mai; Nguyen Trong Kien; Pham Thi Anh Hong

doi:10.55250/Jo.vnuf.9.1.2024.106-116

Keywords:

Acacia hybrid, flame-retardant, mechanical properties, sodium silicate, styrene-acrylic copolymer, wood modification

Abstract

The mechanical and flame-retardant properties of Acacia hybrid wood were studied through the treatment of an aqueous solution containing a styrene-acrylic copolymer (SC) and sodium silicate (SS). The results showed a significant increase in the mechanical properties of SC/SS-treated wood. Specifically, the modulus of rupture (MOR) and modulus of elasticity (MOE) improved by up to 71.54% and 53.65%, respectively. The surface hardness of the cross-section and radial section also increased by 37.24% and 46.65%, respectively. The treated wood’s weight percentage gain (WPG) reached up to 23.31%. The largest leaching rate (LR) of treated wood was only 8.01%, suggesting this treatment has obvious effects in fixing the SS in the wood. However, it did not cause positive bulking efficiency (BE) and anti-swelling efficiency (ASE). The incorporation of SS with SC resulted in the decomposition of polysaccharides at a lower temperature while increasing the limiting oxygen index (LOI), which was 34.95% higher than that of untreated wood, making it more difficult to ignite. Scanning electron microscopy (SEM) results showed that the SC/SS deposited in the cell lumina after polymerization, but significant structural changes occurred, including vessel and cell wall deformation due to the partial dissolution of hemicellulose and lignin from the cell wall in the alkaline solution. The results of this study demonstrate the feasibility of applying the SC/SS combination treatment to wood in practical applications.

References

. Xiaorong Liu, Xinyu Fang, Chen Sun, Tao Zhang, Kaili Wang & Youming Dong (2023). Hybrid Wood Composites with Improved Mechanical Strength and Fire Retardance Due to a Delignification–Mineralization–Densification Strategy. Forests. 14(8): 1567.

. Meihong Liu, Limin Peng, Shaoyi Lyu & Jianxiong Lyu (2020). Properties of common tropical hardwoods for fretboard of string instruments. Journal of Wood Science. 66: 1-11.

. Callum AS Hill (2007). Wood modification: chemical, thermal and other processes. John Wiley & Sons, United Kingdom.

. Arnaud Maxime Cheumani Yona, Jure Žigon, Pavlič Matjaž & Marko Petrič (2021). Potentials of silicate-based formulations for wood protection and improvement of mechanical properties: A review. Wood Science and Technology. 55(4): 887-918.

. Yuan Zhang, Xiaoqian Bi, Ping Li, Yiqiang Wu, Guangming Yuan, Xianjun Li & Yingfeng Zuo (2021). Sodium silicate/magnesium chloride compound-modified Chinese fir wood. Wood Science and Technology. 55: 1781-1794.

. Xiaoqian Bi, Yuan Zhang, Ping Li, Yiqiang Wu, Guangming Yuan & Yingfeng Zuo (2022). Building bridging structures and crystallization reinforcement in sodium silicate-modified poplar by dimethylol dihydroxyethylene urea. Wood Science and Technology. 56(5): 1487-1508.

. Ping Li, Yuan Zhang, Yingfeng Zuo, Jianxiong Lu, Guangming Yuan & Yiqiang Wu (2020). Preparation and characterization of sodium silicate impregnated Chinese fir wood with high strength, water resistance, flame retardant and smoke suppression. Journal of Materials Research and Technology. 9(1): 1043-1053.

. Bingbin Kuai, Ziheng Wang, Jingshu Gao, Jiewei Tong, Tianyi Zhan, Yaoli Zhang, Jianxiong Lu & Liping Cai (2022). Development of densified wood with high strength and excellent dimensional stability by impregnating delignified poplar by sodium silicate. Construction and Building Materials. 344: 128282.

. Li Yan, Feiyang Zeng, Zhangjing Chen, Shuang Chen & Yafang Lei (2021). Improvement of wood decay resistance by salicylic acid/silica microcapsule: Effects on the salicylic leaching, microscopic structure and decay resistance. International Biodeterioration & Biodegradation. 156: 105134.

. Thi Tham Nguyen, Zefang Xiao, Wenbo Che, Hien Mai Trinh & Yanjun Xie (2019). Effects of modification with a combination of styrene-acrylic copolymer dispersion and sodium silicate on the mechanical properties of wood. Journal of wood science. 65(1): 1-11.

. Thi Tham Nguyen, Thi Vinh Khanh Nguyen, Zefang Xiao, Fengqiang Wang, Zhongguo Zheng, Wenbo Che & Yanjun Xie (2019). Combustion behavior of poplar (Populus adenopoda Maxim.) and radiata pine (Pinus radiata Don.) treated with a combination of styrene-acrylic copolymer and sodium silicate. European Journal of Wood and Wood Products. 77: 439-452.

. Malte Pries & Carsten Mai (2013). Treatment of wood with silica sols against attack by wood-decaying fungi and blue stain. Holzforschung. 67(6): 697-705.

. Wenbo Che, Zefang Xiao, Guanghui Han, Zhongguo Zheng & Yanjun Xie (2018). Radiata pine wood treatment with a dispersion of aqueous styrene/acrylic acid copolymer. Holzforschung. 72(5): 387-396.

. T Furuno, Y Imamura & H Kajita (2004). The modification of wood by treatment with low molecular weight phenol-formaldehyde resin: a properties enhancement with neutralized phenolic-resin and resin penetration into wood cell walls. Wood Science and Technology. 37(5): 349-361.

. DP Kamdem, Aea Pizzi & A Jermannaud (2002). Durability of heat-treated wood. Holz als Roh-und Werkstoff. 60(1): 1-6.

. Fan Zhou, Zongying Fu, Yongdong Zhou, Jingyao Zhao, Xin Gao & Jinghui Jiang (2019). Moisture transfer and stress development during high-temperature drying of Chinese fir. Drying Technology. 38(4): 545–554.

. Samuel Oluyinka Olaniran, Benjamin Michen, Diego F Mora Mendez, Falk K Wittel, Erik Valentine Bachtiar, Ingo Burgert & Markus Rüggeberg (2019). Mechanical behaviour of chemically modified Norway spruce (Picea abies L. Karst.): Experimental mechanical studies on spruce wood after methacrylation and in situ polymerization of styrene. Wood Science and Technology. 53: 425-445.

. H Holmberg (2000). Influence of grain angle on Brinell hardness of Scots pine (Pinus sylvestris L.). Holz als Roh-und Werkstoff. 58(1-2): 91-95.

. Wolfgang Gindl, Christian Hansmann, Notburga Gierlinger, Manfred Schwanninger, Barbara Hinterstoisser & George Jeronimidis (2004). Using a water‐soluble melamine‐formaldehyde resin to improve the hardness of Norway spruce wood. Journal of Applied Polymer Science. 93(4): 1900-1907.

. Fangqiang Fan, Zhengbin Xia, Qingying Li, Zhong Li & Huanqin Chen (2013). Thermal stability of phosphorus-containing styrene-acrylic copolymer and its fire retardant performance in waterborne intumescent coatings. Journal of Thermal Analysis and Calorimetry. 114(3): 937-946.

. Ming Gao, Shuying Li & Caiyun Sun (2004). Thermal degradation of wood in air and nitrogen treated with basic nitrogen compounds and phosphoric acid. Combustion Science and Technology. 176(12): 2057-2070.

. Zefang Xiao, Jiejie Xu, Carsten Mai, Holger Militz, Qingwen Wang & Yanjun Xie (2016). Combustion behavior of Scots pine (Pinus sylvestris L.) sapwood treated with a dispersion of aluminum oxychloride-modified silica. Holzforschung. 70(12): 1165-1173.

. Enguang Xu, Dong Wang & Lanying Lin (2020). Chemical structure and mechanical properties of wood cell walls treated with acid and alkali solution. Forests. 11(1): 87.

. FFP Kollmann & IB Sachs (1967). The effects of elevated temperature on certain wood cells. Wood science and technology. 1(1): 14-25.

. MR Ladisch, KW Lin, M Voloch & Gr T Tsao (1983). Process considerations in the enzymatic hydrolysis of biomass. Enzyme and Microbial technology. 5(2): 82-102.

. Raili Pönni, Tapani Vuorinen & Eero Kontturi (2012). Proposed nano-scale coalescence of cellulose in chemical pulp fibers during technical treatments. BioResources. 7(4): 6077-6108.

. Yong Yu, Fengming Zhang, Songming Zhu & Huanhuan Li (2017). Effects of high-pressure treatment on poplar wood: Density profile, mechanical properties, strength potential index, and microstructure. BioResources. 12(3): 6283-6297.