Selected Properties of Formaldehyde-Free Polymer-Straw Boards Made from Different Types of Thermoplastics and Different Kinds of Straw

Abstract

This research investigated the effects of different thermoplastics types and different kinds of straw on selected properties of polymer-straw boards. Polyethylene, polyethylene, and polystyrene of virgin and of recycled origin were used for bonding the boards. Three kinds of straw were used: rape (Brassica napus L. var. napus), triticale (Triticosecale Witt b m.), and rye (Secale L.). Five-layer polymer-straw boards were produced. The obtained boards differed in both the materials they were made of and the moisture content (7, 25, and 2% for the core, the middle, and the face layers, respectively), and 30% of straw particles were substituted with thermoplastics added to the face layers. It was found that properties of polymer-straw boards strongly depend on both the kind of straw and the type of polymer used. The best mechanical properties were obtained for rye straw and polystyrene or recycled polymers, whereas the best hydrophobic properties were observed for rape straw combined with recycled polyethylene or polypropylene. Although recycled polymers improved the hydrophobic properties of the boards, they impaired their mechanical properties in comparison with the reference ones. However, in terms of bending strength, they still met the requirements for heavy duty load-bearing boards for use in humid conditions (20 MPa for P7 boards according to EN 312).

Annual Plants and Thermoplastics in the Production of Polymer and Lignocellulose Boards

“…Mainly WPC is manufactured by methods used in the plastic industry. The exciting approach is flat pressing, which was used by numerous researchers [ 31 , 32 , 33 , 34 , 35 , 36 , 37 ]. The OSB or particleboard with polymer addition in inner layers was characterized by better physical properties, which maintained good mechanical properties.…”

“…In our previous research, we investigated the effect of various types of straw (rye, triticale, and rape) and various type of thermoplastics (HDPE, low-density polyethylene (LDPE), polystyrene (PS), and PP) on the properties of five-layer boards [ 31 ]. The results showed that the properties of the obtained boards strongly depended on both kinds of the polymer and straw used [ 31 ]. The research described by Mihai et al [ 38 , 39 ] indicated that triticale straw has great potential in the production of thermoplastic composites.…”

Effect of the Adhesive System on the Properties of Fiberboard Panels Bonded with Hydrolysis Lignin and Phenol-Formaldehyde Resin

“…The growing demand for eco-friendly wood-based panels with lower environmental footprints and reduced hazardous emissions of volatile organic compounds, such as free formaldehyde from the finished wood composites, have imposed new stricter regulations and requirements on both researchers and industrial practice, related to the development of sustainable, "green" composites [1][2][3][4][5]. The production of fiberboards, with an estimated global production of more than 104 million m 3 in 2020, is the second largest worldwide, surpassed only by the production of plywood [6].…”

Eco-Friendly Wood Composites: Design, Characterization and Applications

“…The harmful formaldehyde released from wood composites can be reduced by adding formaldehyde scavengers to conventional adhesive systems, through the surface treatment of finished wood composites, or by using novel biobased wood adhesives as environmentally friendly alternatives to traditional thermosetting resins [ 39 , 40 , 41 , 42 , 43 ]. Another alternative to formaldehyde-based adhesives is the manufacture of binderless wood-based panels, since wood represents a natural polymeric material abundant in lignocellulosic constituents, such as cellulose, hemicelluloses, and lignin [ 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 ].…”