Effects of poly(diallyldimethylammonium chloride) addition on the curing kinetics of urea-formaldehyde adhesives for particleboards

Jaroslava Budinski-Simendic,Mladjan Popovic,Jasmina Popovic,Nevena Vukic,Milanka Djiporovic-Momcilovic,Ivana Gavrilovic-Grmusa,Ivan Ristic

doi:10.2298/hemind210914001p

Abstract

Addition of poly(diallyldimethylammonium chloride) (PDDA) on the performances of urea-formaldehyde (UF) adhesives was evaluated in this work. Three types of UF adhesives were prepared, one without PDDA addition, and two types with PDDA addition of 1 and 3 wt.% per dry UF adhesive mass. These UF adhesive systems were used for producing experimental particleboard panels. The addition of PDDA decreased the thickness swelling of the panel samples, while the internal bond of the particleboards increased significantly only at the highest PDDA content (3 wt.%). Differential scanning calorimetry (DSC) was applied to address the influence of PDDA on UF adhesive curing kinetics. DSC scans were performed in non-isothermal regimes using different heating rates (5, 10, and 20 ?C?min?1). The activation energy (Ea) of the curing reaction showed slightly lower values for the UF adhesive systems containing PDDA. However, the peak temperatures and enthalpy of reaction did not change significantly. The Kissinger-Akahira-Sunose and Friedman iso-conversional methods were applied to investigate the effects of PDDA addition on the UF adhesive curing process.

Highlights

Poly(diallyldimethylammonium chloride) (PDDA) is a positively charged linear polyelectrolyte (Fig. 1), which can be regarded as both the conducting and ion exchange polymer
The statistical evaluation of these results showed insignificant differences between the panel types, suggesting that the poly(diallyldimethylammonium chloride) (PDDA) addition did not influence these properties
The addition of PDDA into the UF adhesive showed positive effects concerning thickness swelling and internal bond strengths of experimental particleboards. Both of these properties were improved with the application of the higher PDDA content of 3 % per dry UF adhesive

Summary

INTRODUCTION

Poly(diallyldimethylammonium chloride) (PDDA) is a positively charged linear polyelectrolyte (Fig. 1), which can be regarded as both the conducting and ion exchange polymer It is often used in water purification and wastewater treatment, as a coagulation and flocculation agent, as well as in a papermaking process as a pitch control and sizing agent. It was interesting to investigate the ability of PDDA polymer to enhance the adhesion of wood particles in the process of particleboard production. Another goal of this work is to evaluate the effects of the PDDA addition on the curing reaction of urea-formaldehyde (UF) adhesives. The UF adhesive, itself, is still highly used as an adhesive in the wood-based panels industry, for the production of interior classes of particleboards and fibreboards

EXPERIMENTAL

RESULTS AND DISCUSSION

CONCLUSION