Component modulation of bamboo scraps enhances interfacial compatibility and strength of thermal insulation composites

Abstract

The combination of bamboo waste and magnesium oxychloride (MOC) cement is a promising pathway to obtain green, lightweight construction materials. However, bamboo scraps tend to hinder the formation of high-quality pores within composites, and the insufficient bonding strength at the inorganic-organic interface leads to poor performance. We present an eco-friendly ammonium carbonate (AC) treatment strategy to replace traditional processes that use NaOH solution to modulate the components of bamboo. The AC treatment removed substances that interfered with hydration and softened the rigid bamboo skeleton, attenuating its negative effects on pore formation. Furthermore, the exposure of hydrophilic groups facilitated the growth of 5-phase crystals into surface micropores, which created a robust anchoring effect that markedly reduced interfacial defects and brittleness. The composites prepared with this method exhibited a 45% increase in compressive strength, a 12% improvement in the softening coefficient, and a 15% reduction in thermal conductivity, endowing them with enhanced mechanical properties, improved water resistance, and excellent thermal insulation performance. This strategy provides a reference for preparing green, high-performance, biomass-based lightweight composites, as well as for interface modification and high-quality pore structure regulation.

Keywords

Magnesium oxychloride / Composite material / Component modulation / High-strength thermal insulation

References

[1] Agrawal, R., Saxena, N.S., Sreekala, M.S., Thomas, S., 2000. Effect of treatment on the thermal conductivity and thermal diffusivity of oil-palm-fiber-reinforced phenolformaldehyde composites. J. Polym. Sci. B Polym. Phys. 38, 916-921.

[2] Chen, X.Y., Zhang, T.T., Bi, W.L., Cheeseman, C., 2019. Effect of tartaric acid and phosphoric acid on the water resistance of magnesium oxychloride (MOC) cement. Constr. Build. Mater. 213, 528-536.

[3] de Almeida Melo Filho, J., de Andrade Silva, F., Toledo Filho, R.D., 2013. Degradation kinetics and aging mechanisms on sisal fiber cement composite systems. Cem. Concr. Compos. 40, 30-39.

[4] Deng, D., 2003. The mechanism for soluble phosphates to improve the water resistance of magnesium oxychloride cement. Cem. Concr. Res. 33, 1311-1317.

[5] Feng, B., Liu, J., Lu, Z., Zhang, M., Tan, X., 2023. Study on properties and durability of alkali activated rice straw fibers cement composites. J. Build. Eng. 63, 105515.

[6] Gołębiewski, M., Pietruszka, B., Piątkiewicz, W., Kubiś, M., Oleksiienko, O., 2025. Compressive strength, thermal conductivity, vapor permeability and specific heat of hemp-lime composites varying in density for wall, roof and floor applications. Materials (Basel) 18, 4958.

[7] Guo, R., Xue, C.H., Guo, W.C., Wang, S., Shi, Y.X., Qiu, Y.X., Zhao, Q.X., 2023. Preparation of foam concrete from solid wastes: physical properties and foam stability. Constr. Build. Mater. 408, 133733.

[8] Hackenberg, H., Zauer, M., Dietrich, T., Hackenberg, K.A.M., Wagenführ, A., 2021. Alteration of bending properties of wood due to ammonia treatment and additional densification. Forests 12, 1110.

[9] Jiang, L.P., Fu, J.J., Liu, L.H., 2020. Seawater degradation resistance of straw fiber-reinforced polyvinyl chloride composites. BioResources 15, 5305-5315.

[10] Kouadjo Tchekwagep, J.J., Li, Z.H., Huang, S.F., Huang, J.H., Tchakouté, H.K., 2025. Transforming waste into sustainable insulation: a novel thermal insulation board utilizing treated rice husk ash, bagasse ash, and expanded vermiculite in calcium sulfoaluminate cement composite. J. Clean. Prod. 512, 145699.

[11] Li, K., Wang, Y.S., Zhang, X., Wu, J.X., Wang, X., Zhang, A.M., 2021. Intrinsically hydrophobic magnesium oxychloride cement foam for thermal insulation material. Constr. Build. Mater. 288, 123129.

[12] Liu, P., Dong, J.M., Chang, C.G., Zheng, W.X., Liu, X.Q., Xiao, X.Y., Wen, J., 2021. Preparation of low-cost magnesium oxychloride cement using magnesium residue byproducts from the production of lithium carbonate from salt lakes. Materials (Basel) 14, 3899.

[13] Mao, J., Yuan, H., Xiong, L., Huang, B., 2024. Research review of green building rating system under the background of carbon peak and carbon neutrality. Buildings 14, 1257.

[14] Meng, F.D., Yu, Y.L., Zhang, Y.M., Yu, W.J., Gao, J.M., 2016. Surface chemical composition analysis of heat-treated bamboo. Appl. Surf. Sci. 371, 383-390.

[15] Mohanty, A.K., Misra, M., Drzal, L.T., 2001. Surface modifications of natural fibers and performance of the resulting biocomposites: an overview. Compos. Interfaces 8, 313-343.

[16] Pařil, P., Brabec, M., Maňák, O., Rousek, R., Rademacher, P., Čermák, P., Dejmal, A., 2014. Comparison of selected physical and mechanical properties of densified beech wood plasticized by ammonia and saturated steam. Eur. J. Wood Prod. 72, 583-591.

[17] Savastano, H., Warden, P.G., Coutts, R.S.P., 2005. Microstructure and mechanical properties of waste fibre-cement composites. Cem. Concr. Compos. 27, 583-592.

[18] Song, F., Li, Z., Jia, P.Y., Bo, C.Y., Zhang, M., Hu, L.H., Zhou, Y.H., 2020. Phosphorus-containing tung oil-based siloxane toughened phenolic foam with good mechanical properties, fire performance and low thermal conductivity. Mater. Des. 192, 108668.

[19] Tan, Y.N., Liu, Y., Grover, L., 2014. Effect of phosphoric acid on the properties of magnesium oxychloride cement as a biomaterial. Cem. Concr. Res. 56, 69-74.

[20] Wang, F.Z., Yang, L., Guan, L.Y., Hu, S.G., 2015. Microstructure and properties of cement foams prepared by magnesium oxychloride cement. J. Wuhan Univ. Technol.-Mat. Sci. Edit. 30, 331-337.

[21] Wang, G.F., Wei, Y., Wang, J.Q., Zhou, Z.Y., Chen, S.B., Zhu, B.R., 2024. Assessment of the properties of interface-modified bamboo aggregates for sustainable concrete construction. J. Build. Eng. 94, 110069.

[22] Wang, J., Zuo, Y.F., Xiao, J.H., Li, P., Wu, Y.Q., 2019. Construction of compatible interface of straw/magnesia lightweight materials by alkali treatment. Constr. Build. Mater. 228, 116712.

[23] Xia, L.J., Zhang, C.H., Wang, A.M., Wang, Y.L., Xu, W.L., 2020. Morphologies and properties of Juncus effusus fiber after alkali treatment. Cellulose 27, 1909-1920.

[24] Xu, W.H., Song, Z.J., Guo, M.Z., Jiang, L.H., Chu, H.Q., 2022. Improvement in water resistance of magnesium oxychloride cement via incorporation of dredged sediment. J. Clean. Prod. 356, 131830.

[25] Yan, L.B., Chouw, N., Huang, L., Kasal, B., 2016. Effect of alkali treatment on microstructure and mechanical properties of coir fibres, coir fibre reinforced-polymer composites and reinforced-cementitious composites. Constr. Build. Mater. 112, 168-182.

[26] Ye, Q.Q., Han, Y.F., Zhang, S.F., Gao, Q., Zhang, W., Chen, H., Gong, S.S., Shi, S.Q., Xia, C.L., Li, J.Z., 2020. Bioinspired and biomineralized magnesium oxychloride cement with enhanced compressive strength and water resistance. J. Hazard. Mater. 383, 121099.

[27] Yi, J.J., Li, X.G., Xiao, Y.X., Zheng, X., 2025. Multi-bonding network to enable high-strength, thermal insulation of reed fiber/OPC lightweight composites. J. Build. Eng. 100, 111704.

[28] Yu, K.Q., Guo, Y.Y., Zhang, Y.X., Soe, K., 2020. Magnesium oxychloride cement-based strain-hardening cementitious composite: mechanical property and water resistance. Constr. Build. Mater. 261, 119970.

[29] Zhang, A., Zhao, Z.R., Dong, T.Y., Sun, X.Y., Zhang, Y., Zhou, W.G., Li, J.Z., 2024. High-bond-strength, water-resistant magnesium oxychloride cement-based inorganic adhesive inspired by adsorbed heavy metal ions. ACS Sustain. Chem. Eng. 12, 5150-5159.

[30] Zheng, L., Wu, Y.Q., Li, X.G., Zuo, Y.F., 2023. Molecular-level topological deep cross-fusion strategy towards organic-inorganic lightweight composites. Chem. Eng. J. 474, 145666.

[31] Zheng, L., Wu, Y.Q., Wang, S., Sheng, G.A., Sun, B.R., Zuo, Y.F., 2021. Effect of the proportion of bamboo scraps on the properties of bamboo scraps/magnesium oxychloride composites. J. Renew. Mater. 9, 1729-1739.

[32] Zheng, L., Zuo, Y.F., Li, X.G., Wu, Y.Q., 2022. Biomimetic swallow nest structure: a lightweight and high-strength thermal insulation material. ACS Nano 16, 8116-8127.

[33] Zhong, Z.W., Chen, Y.Q., Zhao, H.H., Kang, X., 2024. Effect of foaming agent on physical and mechanical properties of foamed phosphogypsum. J. Mater. Civ. Eng. 36, 04023611.

[34] Zhou, X., Wang, M.Y., Fang, S., Liu, X., Liu, P., 2019. Effect of alkaline black liquor recycling on alkali combined with ozone pretreatment of corn stalk. Molecules 24, 2836.