This study explores the thermal insulation potential and structural viability of rice husk (RH)-reinforced polyester bio-composites for sustainable building applications. Departing from conventional RH usage in ash or powder form, RH is used here as a high-volume structural filler (75–95%) in polymer composites. Increasing RH content significantly reduces thermal conductivity (down to 0.0829 W m−1K−1), density, compressive strength, and ultrasonic pulse velocity, while increasing porosity and water absorption. The composite with 75% RH (P25R75) achieved the highest mechanical performance, while samples with 85–95% RH demonstrated excellent thermal insulation properties. Regression analysis indicates a strong correlation between density and both mechanical and thermal behaviours. Despite high water absorption, the composites show promise as eco-efficient, thermally insulating, non-load-bearing building materials, especially with surface treatments in humid environments. These findings position RH as a viable, low-cost reinforcement in the development of energy-efficient building envelopes.
MohantyAKMisraMHinrichsenG. Biofibres, biodegradable polymers and biocomposites: an overview. Macromol Mater Eng2000; 276–277: 1–24.
2.
JaiswalDDevnaniGLRajeshkumarG, et al.Review on extraction, characterization, surface treatment and thermal degradation analysis of new cellulosic fibers as sustainable reinforcement in polymer composites. Curr Res Green Sustain Chem2022; 5: 100271.
3.
Das GandhiAGMSivaramanRNagabooshnamN, et al.Characterization of heat-treated rice husk Si3N4 bioceramic on cellulosic corn husk fiber-polyester composite. Biomass Convers Biorefinery2024; 14: 29393–29402.
4.
ChandraAPandeyAKPathakB, et al. A study on mechanical properties and water absorption behaviour of jute composites. Indian J Pure Appl Phys. 2021; 59: 63–67.
5.
ArjmandiRHassanAMajeedK, et al.Rice husk filled polymer composites. Int J Polym Sci2015; 2015: 1–32.
6.
ChandrasekharSSatyanarayanaKGPramadaPN, et al.Review processing, properties and applications of reactive silica from rice husk—an overview. J Mater Sci2003; 38: 3159–3168.
7.
ViswanathSBSathees KumarSSudarsanD, et al.Mechanical attributes of coir fibre, rice husk and egg shell reinforced hybrid polyester composites. Mater Today Proc2021; 46: 874–877.
8.
HemnathAAnbuchezhiyanGNanthaKumarP, et al.Tensile and flexural behaviour of rice husk and sugarcane bagasse reinforced polyester composites. Mater Today Proc2021; 46: 3451–3454.
9.
BattegazzoreDAlongiJDuraccioD, et al.All natural high-density fiber- and particleboards from hemp fibers or rice husk particles. J Polym Environ2018; 26: 1652–1660.
10.
AntónioJTadeuAMarquesB, et al.Application of rice husk in the development of new composite boards. Constr Build Mater2018; 176: 432–439.
11.
HamidMRYAb GhaniMHAhmadS. Effect of antioxidants and fire retardants as mineral fillers on the physical and mechanical properties of high loading hybrid biocomposites reinforced with rice husks and sawdust. Ind Crops Prod2012; 40: 96–102.
12.
ChabannesMBénézetJ-CClercL, et al.Use of raw rice husk as natural aggregate in a lightweight insulating concrete: an innovative application. Constr Build Mater2014; 70: 428–438.
13.
SpadaJCJasperATessaroIC. Biodegradable cassava starch based foams using rice husk waste as macro filler. Waste Biomass Valoriz2020; 11: 4315–4325.
14.
FayzullinIGorbachevAVolfsonS, et al.Influence of different dosages of rice husk particles on thermal, physical, mechanical and rheological properties of polypropylene-based composites. J Compos Sci2025; 9: 443.
15.
Van SoestPJRobertsonJBLewisBA. Methods for dietary fiber, neutral detergent fiber, and nonstarch polysaccharides in relation to animal nutrition. J Dairy Sci1991; 74: 3583–3597.
16.
MalikSOmrePKSivadasS. Compositional analysis of the lignocellulosic biomass from agricultural waste (rice husk). Arch Curr Res Int2024; 24: 78–84.
17.
NoviaNPareekVKHermansyahH, et al.Effect of dilute acid - alkaline pretreatment on rice husk composition and hydrodynamic modeling with CFD. Sci Technol Indones2019; 4: 18.
18.
ShahabazuddinMSarat ChandraTMeenaS, et al.Thermal assisted alkaline pretreatment of rice husk for enhanced biomass deconstruction and enzymatic saccharification: physico-chemical and structural characterization. Bioresour Technol2018; 263: 199–206.
19.
AyeniAODaramolaMOSekoaiPT, et al.Statistical modelling and optimization of alkaline peroxide oxidation pretreatment process on rice husk cellulosic biomass to enhance enzymatic convertibility and fermentation to ethanol. Cellulose2018; 25: 2487–2504.
20.
NikzadMMovagharnejadKTalebniaF, et al.Modeling of alkali pretreatment of rice husk using response surface methodology and artificial neural network. Chem Eng Commun2015; 202: 728–738.
21.
JoharNAhmadIDufresneA. Extraction, preparation and characterization of cellulose fibres and nanocrystals from rice husk. Ind Crops Prod2012; 37: 93–99.
22.
BishtNGopePCRaniN. Rice husk as a fibre in composites: a review. J Mech Behav Mater2020; 29: 147–162.
23.
ASTM C597-16. Standard test method for pulse velocity through concrete. American Society for Testing Materials, 2016.
24.
BiniciH. Atık mukavva, alçı, pomza, perlit, vermikülit ve zeolit ile yapılan kompozitlerin yangın direncinin araştırılması. Çukurova Üniversitesi Mühendislik-Mimarlık Fakültesi Derg2016; 31: 1–10.
25.
TS EN 826. Thermal insulating products for building applications - determination of compression behaviour. Turkish Standards Institution, 2022.
26.
ASTM C1113/C1113M-09. Standard test method for thermal conductivity of refractories by hot wire (platinum resistance thermometer technique). Annual Book of ASTM Standards, 2024.
27.
MuthurajRLacosteCLacroixP, et al.Sustainable thermal insulation biocomposites from rice husk, wheat husk, wood fibers and textile waste fibers: elaboration and performances evaluation. Ind Crops Prod2019; 135: 238–245.
28.
Nor ArmanNSChenRSAhmadS. Review of state-of-the-art studies on the water absorption capacity of agricultural fiber-reinforced polymer composites for sustainable construction. Constr Build Mater2021; 302: 124174.
29.
KolakMNOltuluM. Investigation of physical, mechanical and thermal properties of hemp and camelina reinforced polymer composites. Constr Build Mater2025; 487: 142066.
30.
JannahMMariattiMAbu BakarA, et al.Effect of chemical surface modifications on the properties of woven banana-reinforced unsaturated polyester composites. J Reinf Plast Compos2009; 28: 1519–1532.
31.
YigaVALubwamaMOlupotPW. Thermal stability of NaOH modified rice husk fiber-reinforced polylactic acid composites: effect of rice husks and clay loading. Results Mater2023; 18: 100398.
32.
DaiYSunQWangW, et al.Utilizations of agricultural waste as adsorbent for the removal of contaminants: a review. Chemosphere2018; 211: 235–253.
33.
BarczewskiMSałasińskaKSzulcJ. Application of sunflower husk, hazelnut shell and walnut shell as waste agricultural fillers for epoxy-based composites: a study into mechanical behavior related to structural and rheological properties. Polym Test2019; 75: 1–11.
34.
SokolovskayaYGPodymovaNBKarabutovAA. Verification of the Kramers-Kronig relations between ultrasonic attenuation and phase velocity in a finite spectral range for CFRP composites. Ultrasonics2019; 95: 37–44.
35.
Ribeiro FilhoSLMThomasCDurãoLMP, et al.Ultrasonic pulse velocity and physical properties of hybrid composites: a statistical approach. Hybrid Adv2023; 2: 100024.
KolakMN. Utilization of Prangos ferulacea waste stems in polymer composites: effects on thermal insulation and mechanical performance. J Build Eng2025; 108: 112914.
38.
PolatH. Effect of filler-resin ratio on the physical, mechanical and durability properties of heavy aggregate-based polymer composites. Bull Mater Sci2025; 48: 46.
39.
YuXSunL. Strength, microstructure, and thermal conductivity of the insulation wallboards prepared with rice husk fiber and recycled concrete aggregates. PLoS One2018; 13: e0203527.
40.
MarquesBTadeuAAntónioJ, et al.Mechanical, thermal and acoustic behaviour of polymer-based composite materials produced with rice husk and expanded cork by-products. Constr Build Mater2020; 239: 117851.
41.
ÖzerNAcun ÖzgünlerS. Evaluation of performance on the wall sections of insulation materials used in construction. Uludağ Univ J Fac Eng2019; 24: 25–48.
42.
Rodríguez NeiraKCárdenas-RamírezJPRojas-HerreraCJ, et al.Assessment of elaboration and performance of rice husk-based thermal insulation material for building applications. Buildings2024; 14: 1720.
43.
KolakMNOltuluM. Investigation of mechanical and thermal properties of new type bio-composites containing camelina. Constr Build Mater2023; 362: 129779.
44.
HungALDPásztoryZ. An overview of factors influencing thermal conductivity of building insulation materials. J Build Eng2021; 44: 102604.
45.
KoruM. Determination of thermal conductivity of closed-cell insulation materials that depend on temperature and density. Arab J Sci Eng2016; 41: 4337–4346.
46.
PolatH.Experimental investigation of Prangos platychlaena boiss fiber‐reinforced polyester composites for thermal insulation and construction applications. Adv Eng Mater. 2025; 27(23): e202500540.
47.
LiuZLeiYZhangX, et al.Effect mechanism and simulation of voids on hygrothermal performances of composites. Polymers (Basel)2022; 14: 901.
