Characterization of particleboards produced with Orange (Citrus sinensis L.) and Turkey oak (Quercus cerris L.) wood species using Modified Starch as adhesive

The continuing rise in raw material prices imposes the search for new raw materials with low economic competition. Generally, wood species utilized in particleboards (PBs) production are either softwoods like red fir, spruce and pine, or hardwoods like beech, poplar and birch. In recent years, several investigations into the potential advantages of using annual plants, fast-growing species and agricultural residues in the PBs production and on their performances as a raw material for PBs have been conducted. The present research focused on developing PBs produced with wood branches of Orange tree (Citrus sinensis L.) from crops and Turkey oak (Quercus cerris L.) wood residues from forest stand. Orange tree crops predominate the southern part of Italy, and Turkey oak forests are widespread along the Apennine mountain, especially in Basilicata Region. The management of both wood species produces a large amount of biomass often burned in the field or sometimes shredded and left into the soil to increase the organic matter, or used for energy purposes. Generally, PBs are manufactured with Urea-Formaldehyde (UF) as a binder, known as a toxic substance for human health. In this research Corn Starch modified with glutardialdehyde (MS) was promoted as a low environmental impact adhesive. PBs produced with orange and oak wood particles and using two types of adhesives, UF and MS, were compared and evaluated in terms of mechanical properties, such as modulus of elasticity (MOE), modulus of rupture (MOR), and internal bond strength (IB), and physical properties, such as thickness swelling (TS) and water absorption (WA). The obtained data were statistically analyzed using analysis of variance (ANOVA) and Duncan’s mean separation tests. All panels produced with UF adhesive showed good mechanical performances. Panels produced with the mixture of UF and MS showed acceptable MOE and IB values, complying with the minimum requirements of the standard EN 312:2004 for P2 panels type, namely non-structural panels including furniture for use in dry areas. TS values met also the requirement for P3 panels type intended for use in humid conditions, according to the standard EN 312:2004, but only in the case of the panels produced with UF adhesive. The use of MS has negatively affected the physical properties (TS and WA) and resistance to bending (MOR). However, the produced panels showed good performance for indoor applications, where dimensional stability is not a strict requirement.