PLA as a hydrophobic coating material on kraft paper
In a new study, a facile solution casting method for coating poly lactic acid (PLA) on Kraft paper was developed to impart hydrophobicity and to use sustainable materials in the development of coated abrasive products.
The study investigated and explored the possible use of bio-based PLA as a barrier coating material on natural Kraft paper to fabricate coated abrasive products and to replace the conventional, non-biodegradable, synthetic polymer-based barrier coating materials.
PLA was coated on the Kraft paper using a solution coating process.The barrier properties of the PLA-treated Kraft paper were accordingly tested for application as a backing material in coated abrasive products. The concentration of PLA in solution was systematically increased from 5 wt% to 25 wt%. The coating thickness and coating weights were increased quantitatively with increasing solution concentrations.
The morphology of the coating was characterised using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), contact angle, and surface roughness measurements. The mechanical properties of the PLA coating applied Kraft paper were quantified by measuring the tensile strength, bursting strength, air porosity and Cobb value in order to find its suitability as coated abrasive product. The thermal analysis carried out using DSC scan indicated the semi-crystalline nature of PLA.
Superior overall barrier properties
The coating’s analysis for air and water resistance indicated that the air and water resistance increased with increase in PLA coating thickness. The data from different studies revealed that the PLA coating with a coating weight of 9 g m−2 appeared to be the most ideal concentration over the untreated or other lower PLA g m−2 treated backing materials and proved to possess superior overall barrier properties that are essentially needed for the fabrication of coated abrasive products.
The study has been published in Progress in Organic Coatings, Volume 145, August 2020.
