The recently developed process for the removal of all lignins is being used at this time primarily to manufacture boards and storage containers used in archives, in conservation, and in museum-style framing.
Another major consideration in paper is its pH. A very small number of water molecules, HOH, occasionally break up and reform. During the breakup, a positively charged H ion and a negatively charged OH ion are formed. The Hs are acidic and the OHs are alkaline.
Chemistry 2018 HSC exam pack
Water has been assigned a pH value of 7, which represents equal concentrations of acid and alkali. If the concentration of H ions becomes greater than the number of OH ions, then the result is said to be acidic, and a lower number is assigned. A pH of 6, for example, is ten times more acidic than water, and a pH of 5 is ten times more acidic than 6, or one hundred times more acidic than water.
If the concentration of H ions becomes less than the concentration OH ions, the result is said to be alkaline and is assigned a higher number, such as 8, which is ten times less acidic than water or ten times more alkaline than water. The scale ranges from 1 to The more acidic a paper, the faster the cellulose will break down, resulting in a shorter lifespan.
Chemistry For Class 11 Previous Year Question Papers Download in
A number of factors can influence the pH of a paper. Residual acids from processing, rosin or alum sizing, fillers used to create bulk, oils used to make paper transparent, optical brighteners, atmospheric sulfur dioxide, and the presence of lignins can all result in a pH of 4. Recent study has shown that even the purest cotton papers will become slightly acidic, even though they left the mill at pH ranging between 6. Chemistry portal. In Lahre, Thomas ed.
Environmental Protection Agency. Retrieved 7 September Washington, D. October Institute of Quimica : 1— Tappi J. January CS1 maint: uses authors parameter link.
China clay Fiber crop Paper chemicals Papyrus Wood pulp. Authority control NDL : Categories : Papermaking Chemical processes Cellulose Pulp and paper industry. Hidden categories: CS1 maint: uses authors parameter Use dmy dates from September Wikipedia introduction cleanup from September All pages needing cleanup Articles covered by WikiProject Wikify from September All articles covered by WikiProject Wikify Articles needing additional references from September All articles needing additional references Articles with multiple maintenance issues Wikipedia articles with NDL identifiers.
Namespaces Article Talk. Views Read Edit View history.
Magnesium Carbonate. Calcium Hydroxide.
CBSE Class 10 Chemistry Solution,Notes,MCQ,Sample Questions
Magnesium Hydroxide. Abietic Acid. Makeup chemical in sulfate pulping chemical recovery Na 2 SO 4. Sodium Carbonate. An acid type cooking liquor chemical component sometimes used to neutralized residual chlorine in the pulp during the bleaching process. Sodium Hydrosulfite.
Na O Cl. Select to download H - chemistry papers, Select to download Int1 - chemistry papers, Select to download Int2 - chemistry papers, Marking Instructions for chemistry 18 papers found for chemistry, displaying all papers. Select to download NAH - chemistry instructions, Select to download NH - chemistry instructions, Select to download N5 - chemistry instructions, Select to download AH - chemistry instructions, Select to download H - chemistry instructions, Select to download Int1 - chemistry instructions, Select to download Int2 - chemistry instructions, Specimen and exemplar questions papers Specimen question papers are available for National 5, Higher and Advanced Higher qualifications.