Retention is one of the key wet-end chemistry application on paper machine. It allows for incorporation into sheet structure all components of furnish despite of large differences in their sizes. Retention programs work through the flocculation of furnish elements and deliver additional benefit of increased drainage in the early phase of sheet formation. The relative importance of retention and drainage benefits changes between different grades of paper/board and with the basis weight of the product.
 
Retention programs allow to maintain desired yield of the operations and effective utilization of other additives. By doing this retention programs not only  impact overall process cost by reducing sewer losses but also allow reaching expected quality benefits by enabling performance of  functional additives like fillers, sizing, strength additives and dyes. Retaining small particles uniformly in the x-y plane and thickness (z-direction) of the paper allows to provide expected formation levels and reduce two-sidedness of the paper. Retention programs are sensitive to a number of wet end chemistry factors that we discussed in our first webinar – pH, conductivity, cationic demand. Knowledge of this material will be useful in understanding sources of variation, control strategies and process stabilization efforts. Proper selection and application of retentions programs is very important in managing their potential negative impact on formation.
 
In this webinar we will discuss retention fundamentals, retention additives, retention programs and their selection and retention program application. Throughout the presentation we will relate to  retention program stability and its impact on variety of sheet quality aspects.

Dr. Pruszynski (Przem) received his MSc and PhD from University of Poznan, Poland in the area of Physical Organic Chemistry in 1976. He taught for 12 years at this University. After moving to Canada in 1986 he continued research and teaching in Canada at Dalhousie University in Halifax, NS and later at University of Toronto. He started industrial part of the carrier at Dow Chemical Research in 1990 working in the Forest Product Group in Sarnia. Joined Nalco Canada in Burligton, Ontario in 1992 as a Group Leader in R&D. After moving to US he continued with Nalco as a Technical Director in Corporate Pulp and Paper Research. Recently he works as Global Technology Specialist bridging research and development with practical challenges of paper industry. Przem authored and co-authored close to 100 papers and conference contributions in many different areas. He holds 6 US patents in various areas of paper making. He holds 6 US patents in various areas of paper making. In 2008 he received Jasper Mardon Award for the best paper at APPITA Conference in Rotorua. Przem was invited to open 2010 Paper Conference in Guangzhou as a Keynote Speaker.