Process & product complexity
Cellulose is an extremely versatile polymer which can be chemically converted into numerous products. However, it is a natural polymer and therefore subject to significant natural variation depending on the source. Many factors have an influence on the functionality of dissolving wood pulps, including: Wood source (softwood/ hardwood/ species; age, season, climate) Process type (chemistry of cooking and bleaching) Sheet structure (delivery package) Every dissolving wood pulp (DWP) type has unique performance characteristics based on the manufacturing 'history' of that type and a technical understanding of process influences on pulp reactivity is critical for DWP applications. Sappi says that the pulp from its largest DWP mill, Saiccor, is particularly reactive, with the expectation that the DWP produced at its recently commissioned mills, Ngodwana and Cloquet, will also have good reactivity, which makes it ideal for some end products and less so for others. We do not need here to go into all that. But the diagrams alongside help in understanding what is happening at each production stage. There are two primary sources for dissolving pulps – wood and cotton linters, though bamboo and even hemp can provide similar pulps. Comparing wood to cotton provides some insight into why wood is preferable, from an eco poin ? ?Y]??H?[? ??[??\?\? ??? \?????H?\ H [?\?????\?Y?YY?? ?? ? \?\?]X?\?? ?]\?[? ?? X?\?]X?[?H?X??H \?X?\?H? [?Y[? [??? ??\?????^[\K H ?\????H?X??H ZY[Y???H HX?\?H?[? [?\?HX?\?H?X[?[X[?Y?Y??\? ? ?[?H?] ?Y[???\?[? ?]?[? [Y\?[?H ?? X?]?H [? H?X??H ZY[Y???H ZH?[? [?Y ?]?? ??YY ? \?[???]Y??X?K ?\?H?\ H \?\?XZ[? H ?Y\????H H]X?[ \ \??[Z[ K H ??\??H ???????]X??\?\? [?[?[????\\?X?H??[? ?Y\?\? ??? ?[? ?????? ?Y??\?[?X] \?][? ?]\?\? ?[ ???XX?\? ????? Z?\? ??Y? H LL YX\?? ?X] \?H[??K\???\\?Y ?ZY? [???^?[ L?[? ??]\??]\??K
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