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HEAT INDUCED YELLOWING - A SECONDARY PHENOMENON OF CHLORINE-FREE BLEACHING

Objective

The goal of YELLOW is to study the processes occurring in heat-induced discolouration of chlorine free bleached pulps.

It is intended to work out the relationships between the conditions under which pulps where bleached and their tendency to discolour during drying at high temperatures.

It is based on the analysis of the spectroscopic properties and structural changes of cellulose and residual lignin, e.g. the formation of functional groups and chromophores or changes in the degree of polymerization, corresponding to the process conditions.

The final achievement of YELLOW is to create effective countermeasures which will prevent or inhibit to said discolouration.

Otherwise, heat-induced yellowing which is a pronounced problem of the new bleaching technologies will become a serious obstacle to the introduction of
environmental-friendly chlorine free bleaching in the European pulp and paper enterprises at least, a large quality loss had to be accepted.

In this way YELLOW will enhance functional properties of papers made of such pulps as well as promote the application of chlorine free bleaching technologies on an European scale.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

DRESDEN UNIVERSITY OF TECHNOLOGY
Address
Pienner Strasse, 21 - 23
01737 Tharandt
Germany

Participants (3)

CENTRE TECHNIQUE DE L'INDUSTRIE DES PAPIERS, CARTONS ET CELLULOSES
France
Address
Domaine Universitaire - B.p. 251
38044 Grenoble
METSÄ-SERLA CHEMICALS OY
Finland
Address
Kaskinen Hill
64260 Kaskinen
THE FINNISH PULP AND PAPER RESEARCH INSTITUTE
Finland
Address
P.o. Box 70
02151 Espoo