High-Performance Castor Oil-Based Polyurethane Composites Reinforced by Birch Wood Fibers

Abstract

A new method for the preparation of coatings based on renewable biomaterials such as castor oil and birch flour is suggested in this study. The introduction of birch flour in a polyurethane matrix synthesized from castor oil and oligomeric methylene diphenyl diisocyanate (MDI) leads to a more than doubled value of tensile strength and almost doubled strength of adhesion to steel at 20 wt.% loading. The composite with such level loading has tensile strength equal to 7.1 MPa at an elongation at break of 31%, with an adhesion to steel of 3.71 MPa. Hence, the use of such level loading allows for an increase in tensile strength of 887.5% in comparison with that of polyurethane based on neat (as received) castor oil, leading to a decrease in the value of elongation at break. The adhesion to steel of these composites increases by 185.5% in comparison with starting polyurethane. FTIR and SEM studies identified the mechanism of the reinforcement effect of birch fibers. This reinforcement is based on the good wetting of birch fibers by polyurethane with the formation of chemical bonds between them, and the cellulose and lignin components of wood fillers. As a result, we obtained cheap bio-based coatings with acceptable mechanical and adhesion properties.

Access to Functionalized Polycarbonates Derived from Fatty Acid Esters via Catalytic ROCOP and Their Potential in Gel Formulations

“…Castor oil (CO) has received increasing attention in recent years due to its widespread availability for the production of polyurethane gels. − Within the field of art conservation, the demand for materials made from renewable sources is ever-growing and CO-based gels represent a good opportunity due to the availability of the oil and the biodegradability of its gels. In the last years, CO-based gels have been developed to find applications in the field of cleaning and conservation of artworks. − However, these materials often become fragile and unusable for restorers after the absorbance of organic solvents.…”

Performance of castor oil polyurethane resin in composite with the piassava fibers residue from the Amazon

“…In the 1700 to 1600 cm −1 range, the C=O stretching bond from carboxyl and acetyl ester groups is present in the hemicellulose structure. The hemicellulose peak at 1705 cm −1 was not detected in the untreated fiber spectrum [42][43][44] , indicating their relevant remotion promoted by the alkali treatment, as reported in Table 2.…”

Fully Bio-Based and Solvent-Free Polyester Polyol for Two-Component Polyurethane Coatings

“…In recent years, the potential replacement of fossil fuels to produce appropriate monomers using inexpensive and renewable starting materials, such as cellulose, starch, lignin, proteins, vegetable oils and fats, is increasingly being explored [1][2][3][4][5][6][7]. These biobased materials can be used to make bio-based polyester polyols, polyurethane dispersions, modified acrylic dispersions, polyacrylate polyols, polyurethanes, epoxy coatings, powder coatings, UV coatings and printing inks, architectural coatings, wood and plastic coatings, paper coatings, films and others [6,[8][9][10][11][12][13][14][15][16][17][18][19][20][21].…”