The work aims to investigate the synergistic flame-retardant mechanism of camellia oleifera shell (COS) combined with aluminum diethylphosphinate (ADP) and ammonium polyphosphate (APP) for the preparation of halogen-free flame-retardant wood-plastic composites (WPCs). Using polypropylene (PP) as the matrix, COS as the filler, and ADP and APP as synergistic flame retardants, flame-retardant COS/PP composites (PCDP) were fabricated by melt extrusion and injection molding. The flame retardancy, thermal degradation behavior, and mechanical properties of each formulation were evaluated by LOI, UL-94 vertical burning test, CONE, scanning electron microscopy with SEM-EDS, and TG-FTIR. The optimal formulation PCDP-5 achieved an LOI of 28.4% and a UL-94 V-0 rating. Compared with PCDP-1, pHRR, THR, and pSPR decreased by 34.4%, 24.5%, and 15%, respectively, while the tensile modulus, flexural modulus, and notched impact strength increased by 27.4%, 17.6%, and 9.2%, respectively. In conclusion, the lignin contained in COS provides aromatic char-forming sources. Together with ADP and APP, it establishes a multi-component flame-retardant system in which condensed-phase catalytic charring and gas-phase radical trapping act synergistically to deliver effective flame retardancy without appreciable loss of mechanical performance. These findings offer guidance for the application of flame-retardant WPCs in packaging and for the utilization of camellia oleifera shells.
Key words
wood-plastic composites /
camellia oleifera shell (COS) /
flame retardancy /
charring agent /
nitrogen-phosphorus synergy
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
References
[1] 欧荣贤, 姚开泰, 孙理超, 等. 木塑复合材料蠕变特性及预测方法的研究进展[J]. 复合材料学报, 2021, 38(6): 1734-1753.
OU R X, YAO K T, SUN L C, et al.State-of-the-Art of the Creep Characteristics of Wood-Plastic Composite and Its Prediction Methods[J]. Acta Materiae Compositae Sinica, 2021, 38(6): 1734-1753.
[2] 唐伟, 徐俊杰, 孙理超, 等. 轻质高强耐候多元共挤木塑复合材料制备及性能[J/OL]. 复合材料学报, 2025: 1-12[2026-04-15]. doi:10.13801/j.cnki.fhclxb.20251020.004.
TANG W, XU J J, SUN L C, et al. Preparation and Properties of Lightweight, High-Strength and Weather-Resistant Multi-Component Co-Extruded Wood-Plastic Composites[J/OL]. Acta Materiae Compositae Sinica, 2025: 1-12[2026-04-15]. doi:10.13801/j.cnki.fhclxb.20251020.004.
[3] CHEN L, LI D K, HAO X L, et al.Synergistic Strength-Toughness Gradient Design in Co-Extruded WPCS/Carbon Fabric Prepreg Composites for High-Performance Architectural Components[J]. Construction and Building Materials, 2025, 495: 143728.
[4] DING C X, PAN M Z, CHEN H, et al.An Anionic Polyelectrolyte Hybrid for Wood-Polyethylene Composites with High Strength and Fire Safety via Self-Assembly[J]. Construction and Building Materials, 2020, 248: 118661.
[5] KALALI E N, ZHANG L, SHABESTARI M E, et al.Flame-Retardant Wood Polymer Composites (WPCS) as Potential Fire Safe Bio-Based Materials for Building Products: Preparation, Flammability and Mechanical Properties[J]. Fire Safety Journal, 2019, 107: 210-216.
[6] XU B R, DENG C, LI Y M, et al.Novel Amino Glycerin Decorated Ammonium Polyphosphate for the Highly-Efficient Intumescent Flame Retardance of Wood Flour/Polypropylene Composite via Simultaneous Interfacial and Bulk Charring[J]. Composites Part B: Engineering, 2019, 172: 636-648.
[7] YANG R F, FU Y Q, ZHU J H, et al.Intimate Contacted 0D/2D Hierarchical Nanocomposite Produces Mechanically Strong and Flame Retardant Wood Plastic Composite[J]. Industrial Crops and Products, 2025, 223: 120165.
[8] 王菁, 陈蕾, 李圣军, 等. 化学型膨胀阻燃剂的研究进展[J]. 工程塑料应用, 2022, 50(11): 157-162.
WANG J, CHEN L, LI S J, et al.Research Progress of Chemical Intumescent Flame Retardants[J]. Engineering Plastics Application, 2022, 50(11): 157-162.
[9] ZHAO P P, GUO C G, LI L P.Exploring the Effect of Melamine Pyrophosphate and Aluminum Hypophosphite on Flame Retardant Wood Flour/Polypropylene Composites[J]. Construction and Building Materials, 2018, 170: 193-199.
[10] LENG Y M, ZHAO X, FU T, et al.Bio-Based Flame-Retardant and Smoke-Suppressing Wood Plastic Composites Enabled by Phytic Acid Tyramine Salt[J]. ACS Sustainable Chemistry & Engineering, 2022, 10(15): 5055-5066.
[11] ZHOU X Z, FU Q L, ZHANG Z J, et al.Efficient Flame-Retardant Hybrid Coatings on Wood Plastic Composites by Layer-by-Layer Assembly[J]. Journal of Cleaner Production, 2021, 321: 128949.
[12] LIU X Q, HU C S, LONG H B, et al.Influence of Hemicelluloses on the Formation of Regenerated Camellia Oleifera Shells Holocellulose Films[J]. International Journal of Biological Macromolecules, 2025, 318: 144821.
[13] GAO W H, TU Q Y, TANG X M, et al.Characteristics of Lignin Isolated from an Agricultural By-Product: Camellia Oleifera Shell[J]. Industrial Crops and Products, 2024, 219: 118973.
[14] LIU L N, QIAN M B, SONG P A, et al.Fabrication of Green Lignin-Based Flame Retardants for Enhancing the Thermal and Fire Retardancy Properties of Polypropylene/Wood Composites[J]. ACS Sustainable Chemistry & Engineering, 2016, 4(4): 2422-2431.
[15] DAI P, LIANG M K, MA X F, et al.Highly Efficient, Environmentally Friendly Lignin-Based Flame Retardant Used in Epoxy Resin[J]. ACS Omega, 2020, 5(49): 32084-32093.
PDF(9081 KB)
