Plywood Production Research Articles

An organic-inorganic dual network built in fast-growing wood veneers to improve the flame retardant and mechanical properties of plywood

Fast-growing wood is widely used in plywood production due to its short growth cycle and low cost. However, its loose fiber structure, inferior material quality, and high flammability significantly limit the application range of plywood products and hinder high-value utilization. This paper reports a simple method for modifying fast-growing wood veneers. We modified phenolic resin with Mg(OH)₂@nano-silica composite particles and impregnated it into the veneers, constructing an organic-inorganic hybrid dual-network structure on both the surface and interior of the veneers. The plywood prepared from the modified veneers exhibited a bending strength of 115.6 MPa, a modulus of elasticity of 9.7 GPa, and a wet shear strength of 2.1 MPa, representing increases of 86.1%, 47.0%, and 90.9%, respectively, compared to plywood made from unmodified veneers. Additionally, the peak heat release rate decreased by 15.3%, and the ignition time was extended to 26 seconds. The uniformly distributed inorganic network effectively mitigated stress concentration and, together with the phenolic resin, formed an efficient thermal insulation layer, enhancing the flame retardancy of the material. This study offers a simple and effective treatment method for reinforcing fast-growing wood veneers, promoting the use of fast-growing wood in high-performance applications.

Improving Indoor Air Quality: Using Polymate-777A as a Formaldehyde Scavenger to Decrease Formaldehyde Emission in Plywood Panels

Indoor air quality is significantly impacted by volatile organic compounds, with formaldehyde being a prominent concern due to its emission from wood composite products. Formaldehyde emissions from wood composite products is a big concern for the environment and people's health. This study focused at how effective a product called Polymate-777A, the additive used as a formaldehyde scavenger is in reducing the formaldehyde emissions from plywood. This study investigates the efficacy of Polymate-777A, a formaldehyde scavenger, in reducing formaldehyde emissions from plywood panels. Through a series of controlled experiments, it was evaluated the impact of varying concentrations of Polymate-777A on formaldehyde release, utilizing standardized testing methods to quantify emissions. Results indicate that the incorporation of Polymate-777A significantly reduces formaldehyde levels, enhancing the safety and environmental sustainability of plywood products. The Results revels that when 1.5% or more Polymate-777A was used as scavenger for plywood manufacturing, the plywood met the emission standards set by Japan and Europe for formaldehyde emissions. This study suggests that using Polymate-777A could be a good way to reduce formaldehyde emissions from wood products, which would be better for the environment and people's health.

A lignin-first biorefinery by integrated deep eutectic solvents towards formaldehyde-free plywood adhesive and monomeric sugars

A profitable and sustainable biorefining process will facilitate its scale-up production. In this study, we combined the advantages of both organic acid-based DES and polyol-based DES into a new ternary DES basing on the lignin-first biorefinery to fractionate bamboo, directly obtained a superstrong lignin adhesive and improved enzymatic saccharification. This integrated DES could enhance the enzymatic saccharification yield to 100 % by substantial removals of lignin (76.25 %) and xylan (79.72 %). Remarkably, the obtained lignin was modified and stabilized by polyols during the fractionation, possessing a well-stabilized β-O-4 structure (as high as 42.66/100Ar), which showed excellent adhesion performance of dry and wet bonding strength (1.87/1.62 MPa), outperforming the commercial phenolic resin and urea resin for plywood production. The formation mechanism of the lignin adhesive was comprehensively studied and demonstrated to be the graft reactions induced by the diol hydroxyl tails onto the α position of lignin’s side chain via etherification. This work proved that the combination of organic acid and polyol-based DES is an ideal strategy to generate a formaldehyde-free plywood adhesive and digestible carbohydrates as coproducts.

The Potential Alternative Antibacterial Activity of Falcata (Falcataria Falcata) Leaf Methanolic Extract against Staphylococcus Aureus and Escherichia Coli

The Potential Alternative Antibacterial Activity Of Falcata (Falcataria falcata) Leaf Methanolic Extract Against Staphylococcus aureus And Escherichia coli  Laliefe B. Arnan; Katherine Joy S. Escueta; Nor Rashida P. Rashid; Elyca M. Tacbobo; Queenie Rose M. Tinoy  Degree: Bachelor of Science in Pharmacy  Thesis Adviser: Junnin Gay L. Garay, RPh, CPh, MS Pharm Falcata is a plant that can be found in the Philippines and is used for the production of wood veneer and plywood. While in Indonesia, it is used as traditional remedy for malaria (Budiarti et al. 2020). They belong to the Fabaceae family, a family known for having great antibacterial effects (Gamo et al. 2015). This study used a percolation extraction method and the percentage yield is calculated to determine the yield from the falcata extract. Disc diffusion method is used for susceptibility testing and determining the zone of inhibition for the different groups. The CLSI guidelines for Staphylococcus aureus and Escherichia coli will be used to determine the antibacterial effect of the extract, in terms of resistance, intermediate, and susceptible results. From the results, the percentage yield of the methanolic crude leaf extract of Falcataria falcata is 2.67%. Leaves from the Falcataria falcata plant were extracted and tested against bacteria. The extracts showed promise in inhibiting the growth of Staphylococcus aureus and Escherichia coli bacteria, with 75% concentration as being more effective. However, these bacteria showed some resistance to all extract concentrations: S. aureus (90% - resistant, 75% - intermediate, 50% - resistant, 25% - resistant); E. coli (90% - resistant, 75% - resistant, 50% - resistant, 25% - resistant). Further study is needed to determine the exact antibacterial properties of the plant.

The Influence of Various Modifications of Hazelnut Shell Flour as Potential Filler in Plywood Technology.

This study investigates the potential of utilizing hazelnut shells (HS) as an innovative filler in three-layer plywood technology, addressing the growing need for sustainable, high-performance materials. Traditional plywood production relies on adhesives enhanced with various fillers to improve physical, mechanical, and operational characteristics. This research explores using native, chemically modified, and activated carbon derived from hazelnut shells as fillers in urea-formaldehyde (UF) resin. The produced plywood's mechanical properties, water absorption, and formaldehyde emissions were thoroughly analyzed. Key findings demonstrate that incorporating 10 part by weight (pbw) native hazelnut shell flour significantly enhances the modulus of rupture (MOR) to 138.6 N mm-2 and modulus of elasticity (MOE) to 13,311 N mm-2. Chemically modified hazelnut shell flour achieves optimal results at 5 pbw, while activated carbon from hazelnut shells, even at 1 pbw, markedly improves bonding strength (2.79 N mm-2 referred to 0.81 N mm-2 for reference sample without filler added). Notably, activated carbon effectively reduces formaldehyde emissions (2.72 mg 100 g-1 oven dry panel referred to 3.32 mg 100 g-1 oven dry panel for reference samples with 10 pbw filler) and improves water resistance, indicating better further dimensional stability and lower environmental impact. The study also shows that excessive filler content negatively affects strength parameters, confirming the importance of optimizing filler concentration. These results highlight the potential of hazelnut shells as an eco-friendly alternative filler in plywood production, contributing to waste valorization and environmental sustainability. This study supports the practical application of hazelnut shell fillers, promoting a circular economy and reducing reliance on traditional, less sustainable materials, thus providing a valuable solution for the wood composite industry.

Utilization of Fibrous Mat Residues from Upholstered Furniture as Sustainable Fillers in Plywood Production.

Nonwoven upholstery fabric is a waste product which is mainly generated during upholstered furniture production. The polyester composition makes it problematic to recycle and reuse this product. This study examined the manufacturing process of nonwoven fabric-reinforced plywood composites and their selected mechanical and physical properties. Nonwoven fabric was integrated between veneers bound with urea-formaldehyde resin to improve standard layered composites' mechanical and physical properties. Several board variants were produced, differing in the position of the nonwoven layers in the composite structure. The composites were evaluated for modulus of rupture (MOR), modulus of elasticity (MOE), internal bond, and screw withdrawal resistance, among others. The results showed that the addition of nonwoven fabric significantly improved some properties, like internal bond and screw withdrawal resistance. Variants with strategically placed nonwoven layers showed the highest performance increases. The results underscore the potential of nonwoven fabric as an effective reinforcing material, offering a path to developing high-performance plywood composites suitable for demanding applications. Another environmental advantage is that the nonwoven fabric waste used in the tested plywood production has not been subjected to burning or landfilling but, through its incorporation into plywood structure, has positively contributed to the Carbon Capture and Storage (CCS) policy. The findings advocate for a circular economy approach, in which industrial waste is effectively repurposed, contributing to the development of green materials in the wood-based composite industry.

Introduction of aldehyde groups into surface of pine bark via Cannizzaro reaction to improve Urea-formaldehyde resin properties

Pine bark, a natural and renewable forest residue, was modified using a simple interfacial solid-phase chemical method to design a highly chemically reactive additive for urea-formaldehyde (UF) resin. The modification introduced carbonyl groups onto the bark surface during the glyoxal reaction at the bark-solid interface. Thermal properties, including curing temperatures, of UF, UFB, and UFGB were evaluated using DSC and DMA. Glyoxal modification of bark significantly influenced these properties, facilitating the crosslinking and curing of adhesives. Notably, plywood bonded with UFGB resin released approximately half as much formaldehyde (52.89 % less) compared to plywood bonded with UF resin, reducing from 1.38 to 0.65 mg/L. Additionally, the wet shear strength of plywood increased by 197.3 %, from 0.37 MPa to 1.10 MPa, exceeding the minimum requirement (0.7 MPa) defined by the China national standard (GB/T 17657–2013). The study presents a compelling case for the utilization of glyoxal-modified pine bark as a filler in UF adhesive for plywood manufacturing. The demonstrated improvements in plywood properties and formaldehyde emissions, along with the environmentally friendly nature of the approach, make it a promising avenue for sustainable plywood production. Further investigations into the underlying mechanisms and long-term performance are encouraged to solidify the potential of this technology.

The Effect of Hardwood Veneer Densification on Plywood Density, Surface Hardness, and Screw Withdrawal Capacity

Increasing environmental awareness and the carbon-storing capability of wood have amplified its relevance as a building material. The demand for high-quality wood species necessitates exploring alternative, underutilized wood sources due to limited forest areas and premium wood volume. Consequently, the veneer-based industry is considering lower-value hardwood species like grey alder (Alnus Incania), black alder (Alnus glutinosa), and aspen (Populus tremula) as substitutes for high-quality birch (Betula pendula). Initially less appealing due to their lower density and mechanical properties, these species show promise through densification, which enhances their density, strength, and hardness. This study aims to enhance plywood screw withdrawal capacity and surface hardness by densifying low-density wood species and using them in plywood face-veneer layers, or in all layers. The relationship between the wood density, surface hardness, and screw withdrawal capacity of plywood made of low-value species like aspen and black alder is examined. Experimental work with a pilot-scale veneer and plywood production line demonstrates improved surface hardness (65% and 93% for aspen and black alder, respectively) and screw withdrawal capacity (16% and 35% for aspen and black alder, respectively) in densified face veneer plywood. This research highlights the potential of densified low-value wood species to meet construction requirements, expanding their practical applications.

Pemberdayaan Ekonomi Perempuan melalui Usaha Mikro: Kasus Pembuatan Triplek di Desa Jerukgiling Kabupaten Kendal

This study examines microeconomic activities in the form of part-time plywood manufacturing in Jerukgiling Village, Kendal Regency, which has been running for two years and involves ten workers. Plywood production is carried out by housewives as an additional job after completing household chores and activities in the rice fields. With a price of Rp1,200 per sheet, plywood production provides additional income for families in the village. The raw materials for making plywood come from sengon and jagon wood, provided by Mr. Gunawan, a boss from Brayu Hamlet, Kertosari Village, Singorojo Subdistrict, Kendal District. The production process is carried out in a special place that is now available, unlike before when it was done in each house. Plywood is collected every day with a production quantity of 200-300 pieces, although payment is made at a later date. The study also found that working hours are flexible, with production activities extending into the evening. The health center routinely checks the health of the workers every month to ensure that their health conditions are maintained. The analysis concludes that this plywood-making business not only provides economic benefits, but also provides flexibility for housewives in carrying out their dual roles. The main resource person for this research was Mrs. Karomah, one of the workers, who provided a detailed description of the dynamics and challenges faced in running a plywood-making business while taking care of their children

Co-production of high-concentration fermentable sugar and lignin-based bio-adhesive from corncob residue via an enhanced enzymatic hydrolysis

Xylose plants (produce xylose from corncob through dilute acid treatment) generate a large amount of corncob residue (CCR), most of which are burned and lacked of valorization. Herein, to address this issue, CCR was directly used as starting material for high-solid loading enzymatic hydrolysis via a simple strategy by combining PFI homogenization (for sufficient mixing) with batch-feeding. A maximum glucose concentration of 187.1 g/L was achieved after the saccharification with a solid loading of 25 wt% and enzyme dosage of 10 FPU/g-CCR. Furthermore, the residue of enzymatic hydrolysis (REH) was directly used as a bio-adhesive for plywood production with both high dry (1.7 MPa) and wet (1.1 MPa) surface bonding strength (higher than the standard (0.7 MPa)), and the excellent adhesion was due to the interfacial crosslinking between the REH adhesive (containing lignin, free glucose, and nanosized fibers) and cell wall of woods. Compared with traditional reported adhesives, the REH bio-adhesive has advantages of formaldehyde-free, good moisture resistance, green process, relatively low cost and easy realization. This study presents a simple and effective strategy for better utilization of CCR, which also provides beneficial reference for the valorization of other kinds of lignocellulosic biomass.

Employing a mixture of fine-particle PKS, glycerol, and citric acid as an eco-friendly binder for plywood production from rubberwood (Hevea brasiliensis) veneer

Biomass-based adhesives, which are environmentally friendly and sustainable materials enabling low formaldehyde wood composites, have garnered interest. Therefore, palm kernel shells (PKS), available as industrial agricultural residue and rich in lignin, are mixed in form of fine particles with glycerol and citric acid, and tested as a candidate for binder in plywood production. The study focused on examining the effects of two factors: the quantity of adhesive used and the pressing temperature. Glycerol and citric acid are low-cost non-toxic chemicals that activate the functional groups and induce changes in the PKS component during hot pressing. Consequently, the mixtures with PKS as fine particles could cross-link with rubberwood veneer, forming a plywood panel with shear strength and bending strength that meet the requirements outlined in ISO 12466-2: part 2, and in Thai industrial standard (TIS 178-2549) for indoor use. The properties of plywood were primarily influenced by the pressing temperature rather than by the quantity of adhesive. Specifically, the temperatures 180 °C and 200 °C enhanced the extent to which the molten binder penetrated the rubberwood surface, consequently improving the mechanical properties and water resistance of the bonding.

Magnetically processed composite material for the production of plywood based on compacted aspen veneer (Populus tremula L.) and a complex binder with nanocrystalline cellulose

Magnetically processed composite material for the production of plywood based on compacted aspen veneer (Populus tremula L.) and a complex binder with nanocrystalline cellulose

Greenhouse gas Emissions Deployment (GED): A novel Lean method for mitigating greenhouse gas emissions in industrial environment

This paper presents a novel methodology specifically developed for measuring and reducing Greenhouse gas (GHG) emissions in production systems and logistics, named Greenhouse gas Emissions Deployment (GED). Thanks to its step-by-step procedure, it enables industries to systematically identify GHG emissions caused by organizational losses, ineffective usage losses, and design losses that need to be tracked and removed in order to operate in the most efficient and environmentally sustainable way. By customizing the Manufacturing Cost Deployment structured use of matrices, GED can detect losses, evaluate cause-effect relations, and support improvement prioritization. First, the losses affecting emissions are identified and their relationship is analysed to identify the underlying causes. Each causal loss is then evaluated according to the total amount of emissions it generates, which are also converted into appropriate economic terms. Finally, to select the correct improvement actions, a cost/benefit analysis is performed based on technical and economic factors that include both cash flows and the marketing impact on the end customer due to the commitment to sustainability. The proposed approach was applied to a major company operating in the plywood production sector in order to demonstrate its validity and effectiveness in production systems.

Modified Buckwheat Husk as a Filler for Urea-Formaldehyde Resin in Plywood Production.

The aim of the presented research was to determine the suitability of both non-modified and modified buckwheat husk (BH) as a filler for urea-formaldehyde adhesive in plywood production. The effect of two modification methods, acetylation and silanization, was investigated. Infrared spectroscopy outcomes confirmed that both acetylation and silanization of the filler had occurred. Based on the results, it was found that the introduction of BH had a significant effect on both the adhesive properties and the characteristics of the manufactured plywood. The application of non-modified husks led to a reduction in viscosity and an extension of the gelation time, and the produced plywood boards were characterized by reduced bonding quality and increased delamination. Modification of the husk surface by acetylation and silanization with 3-aminopropyltriethoxysilane contributed to the noticeable improvement in the resin properties. On the other hand, the improvement in plywood properties, consisting of the increase in bonding quality and reduced delamination, was observed only in the case of the silanized husk. Furthermore, the use of non-modified and acetylated husk did not significantly influence the formaldehyde emission. The reduction in the investigated emission of formaldehyde was observed only in the case of variants containing 15 and 20% of silanized buckwheat husk.

High-amylose starch-based gel as green adhesive for plywood: Adhesive property, water-resistance, and flame-retardancy

The escalating demand for environmentally sustainable and cost-effective adhesives in the wood processing and manufacturing sector has prompted exploration into innovative solutions. This study introduces a novel gel adhesive composed of chemically unmodified high-amylose starch (G70, with 68 % amylose content) with a minimal proportion of urea-formaldehyde (UF) (UF/starch = 1:10, w/w). This G70/UF gel demonstrates remarkable adhesive capabilities for wooden boards under both dry conditions (with a shear stress of 4.13 ± 0.12 MPa) and wet conditions (with a shear strength of 0.93 ± 0.07 MPa after 2 h of water soaking). The study unveils that the elevated amylose content in the starch, coupled with a meticulously controlled isothermal process during bonding, is crucial for these enhancements. Specifically, the robust cohesion of amylose chains expedites phase separation between starch and UF, while the isothermal process facilitates the migration and enrichment of UF molecules at the gel-board and gel-air interfaces. Lacking these mechanisms, conventional amylopectin-rich starch/UF gels (27 % amylose content) show minimal improvement. Moreover, the G70/UF gel showcases exceptional fire retardancy. In all, the G70/UF gel presents a promising alternative for plywood production, reducing reliance on unhealthy UF resin while offering satisfactory bonding resistance in diverse conditions and superior flame retardancy.

A facile strategy to fabricate low viscosity and high cold tack soy protein-based adhesive for particleboard production

The utilization of soy protein as a wood adhesive has been successfully implemented in the industrial production of plywood. However, it is still a significant challenge to directly utilize soy protein-based adhesive for the fabrication of particleboard owing to its high viscosity and low cold tack. In this study, polyvinyl acetate (PVAc) emulsion was used to modify soy protein-based adhesive to reduce its viscosity and enhance its cold tack. By incorporating a content of 30% PVAc emulsion, the viscosity of the adhesive was reduced to 880 mPa·s, which was much lower than the pure soy protein-based adhesive value. Simultaneously, the cold tack was significantly increased by nearly 500 times after the addition of PVAc. The obtained adhesives met the requirements for particleboard production. In addition, the internal bonding strength of the produced particleboard reached 0.7 MPa, significantly exceeding the requirements for P6-grade particleboards (≥ 0.40 MPa, GB/T4897–2015). Moreover, it exhibited no formaldehyde emissions, making it a high-quality particleboard suitable for furniture applications. This study successfully presents a soy protein-based adhesive suitable for particleboard production using a simple blending modification approach, thereby expanding the application scope of soy protein-based adhesives.

Predictive Modeling and Optimization of Plywood Drying: An Artificial Neural Network Approach

Introduction: This investigation delves into the optimization of the plywood drying process through the development of predictive models for output moisture content (MC_Out) and waviness. It focuses on bridging the gap in current methodologies by employing artificial neural networks (ANNs), optimized with genetic algorithms, to enhance prediction accuracy and process efficiency. Materials and Methods: A comprehensive experimental design was employed, analyzing the effects of three wood types (Doncel, Tamburo, and Zapote), two thickness levels, and three drying speeds on MC_Out and waviness. Data collected were subjected to both traditional statistical analysis and ANNs. The ANNs were fine-tuned through genetic algorithms, exploring different network architectures to achieve optimal predictive performance. Results: Statistical models revealed the significant influence of wood type, thickness, and drying speed on MC_Out and waviness, explaining 95.9% and 84.3% of the variations, respectively. The optimized ANN models, however, demonstrated superior accuracy, with the MC_Out model achieving fitted R-squared values of 0.940 and 0.757 for training and validation sets, respectively, thus outperforming traditional models in predicting drying outcomes. Discussion: The study underscores the effectiveness of ANNs in capturing complex nonlinear relationships within the plywood drying data, which traditional statistical models might not fully elucidate. The successful optimization of ANN architecture via genetic algorithms further highlights the potential of machine learning approaches in industrial applications, offering a more precise and reliable method for predicting drying process outcomes. Conclusion: The integration of artificial neural networks, optimized through genetic algorithms, represents a significant advancement in the predictive modeling of plywood drying processes. This approach not only offers enhanced prediction accuracy for key variables such as MC_Out and waviness but also paves the way for more efficient and controlled drying operations, ultimately contributing to the production of higher-quality plywood.

The Removal of Formaldehyde from Urea Formaldehyde Adhesive by Sodium Borohydride Treatment and Its Application in Plywood.

The global production of plywood is constantly increasing as its application in the furniture and interior decoration industry becomes more widespread. An urgent issue is how to decrease the formaldehyde released from plywood, considering its carcinogenic effect on humans and harm to the environment. Reducing the free formaldehyde content of the urea formaldehyde (UF) adhesives used in the preparation process is considered an effective method. Therefore, it is necessary to identify a new type of formaldehyde scavengers. Here, the strongly reducing substance sodium borohydride was used to reduce and degrade the free formaldehyde in UF adhesives, and its effects on the properties of the UF adhesive and plywood were studied. When 0.7% sodium borohydride was added to the UF adhesive with a molar ratio of formaldehyde to urea of 1.4:1, the free formaldehyde content of the UF resin decreased to 0.21%, which is 53% lower than that of the untreated control. Moreover, the formaldehyde released from the plywood was reduced to 0.81 mg/L, ~45% lower than that from the group. The bonding strength of the treated samples could reach ~1.1 MPa, which was only reduced by ~4% compared to that of the control. This study of removing formaldehyde from UF adhesive by reduction could provide a new approach for suppressing formaldehyde release from the final products.

Molded Plywood with Proportions of Beech Bark in Adhesive Mixtures: Production on an Industrial Scale.

Molded plywood is used for furniture components such as seats, backrests, or integral seat shells, and it must be durable and harmless to health. Molded plywood is made with urea-formaldehyde (UF) adhesives; therefore, the issue of the fillers used in them is important. The potential of using ground beech (Fagus sylvatica L.) bark as an eco-friendly additive in UF adhesives for molded plywood manufacturing was investigated in this work. Wheat flour was used as a reference filler. The beech bark (BB) level as a filler was 10%, a value verified under laboratory conditions. Nine-layer flat and molded plywood were produced under industrial conditions from beech veneers bonded with a UF adhesive mixture. The mechanical (bending strength and bonding quality) and physical (swelling and absorbency values after 2 and 24 h) properties of the industrially fabricated molded plywood were evaluated and compared with the European standard requirements (EN 310 and EN 314-2). The mechanical properties of the molded plywood with the addition of BB in the adhesive mixture were acceptable and met these standards' requirements. The positive effect of BB in the UF adhesive mixture on a reduction in formaldehyde emissions from the molded plywood was also confirmed. BB, considered to be wood-processing industry waste or a by-product, has significant potential to be used as a filler in UF resins for molded plywood production, providing an environmentally friendly, inexpensive solution for the industrial valorization of bark as a bio-based formaldehyde scavenger.

Effects of wheat flour levels on the thermal curing behavior of Urea–Formaldehyde and Phenol–Formaldehyde resins

Urea–formaldehyde (UF) and phenol–formaldehyde (PF) resins are the most prevalent adhesives in the manufacturing of wood composites, and they are cured by hot pressing to build a three-dimensional network structure in the composites. UF and PF resins are typically formulated with organic fillers like wheat flour to control viscosity and reduce costs in the commercial production of plywood. Although this formulation is well established, research on the effect of filler on the curing behavior of UF and PF resins has been insufficient. Therefore, this study used differential scanning calorimetry (DSC) to examine the influence of wheat flour as a filler in varying amounts on the thermal curing behavior of UF and PF resins. The results demonstrated that the viscosity and solid content of the UF and PF resins increased as the filler amount increased. In contrast, the gelation time, which reflected the curing speed of the resins, decreased as the filler content increased. Similarly, DSC results demonstrated that with increased filler amounts, the curing reaction of UF resins accelerated, as evidenced by a decrease in the apparent activation energy (Ea) determined using the Kissinger–Akahira–Sunose and Vyazovkin methods. However, in the case of PF resins, the average Ea increased and subsequently declined when 10% and 20% fillers were added. This demonstrated the complicated interaction between wheat flour and resins, particularly PF resins. Furthermore, the isothermal DSC curves reveal that the highest exothermic peaks of UF resins are observed at different isothermal temperatures as the filler amount increases. In contrast, PF resins maintain an isothermal temperature for the highest exothermic peaks across all filler levels. In addition, FTIR analysis suggested that wheat flour might contribute to the curing reaction of UF and PF resins.