Referring to the Complexity of AKD sizing problem, today it is mainly about the separation and analysis of AKD (unbound AKD) and AKD (bound AKD), and also a little bit about the separation analysis of AKD monomers and polymers.
First of all, it is stated that today’s material is mainly from Document 1, which was published in 2016 and is relatively new.
The above literature is an overview article with many highlights (see appendix), and the last sentence of the article deserves special attention, as it is written as: While AKD is used as commercial sing agent for more than six decades, studies on separation, extraction and decision and of different forms of AKD present in this paper, and their rols is needed to better understand the mechanism of AKD sizing, I think this sentence is more interesting, and it is apprppriate to put this sentence in the beginning or end of an article.
The drawings are only used to visualize the meaning of “tracking”
Let’s expand the narrative in four levels:
- Separation and analysis of unponsored AKD (UAKD).
The separation of UAKD is relatively simple, mainly using tetrahydrofuran (THF), hexane, isoanthropane, methyl butyl ether, chloroform, dichloromethane and other methods to extract paper or white water, then the extract is analyzed by gas chromatography, liquid chromatography-mass spectrometry, nuclear magnetic resonance spectrum, Fourier transformation infrared spectrum, potential titration and so on.
- The separation and analysis of AKD (BAKD)
For BAKD, the sample is first acidified (e.g. with hydrochloric acid) or alkalinized (e.g. with sodium carbonate) so that the ester bond between AKD and cellulose (or starch) is disconnected.Samples were then pumped with solvents such as tethydrofuran, hexane, isopane, toluene and acetone (also known as “hydrolycing extraction”),then gas chromatography, MRI spectrum, UV visible spectrum, liquid chromatography-mass spectrometry, Fourier transform infrared spectrum, and near-infrared spectrum
were used for analysis.
- The separation and analysis of AKD polymers
It is reported that AKD polymers themselves cannot be drawn directly, so other components in the sample need to be removed to obtain polymers, and then analyzed by Size Exclusion Chromatography (SEC), lysed gas chromatography-mass spectrometry, etc.
- AKD’s analysis
For AKD, its hydrolysing can be converted into fatty ketones and then analyzed using gas chromatography. However, using the principle of carbon dioxide produced in the process of AKD hydrolysing, the amount of carbon dioxide produced can be analyzed using the top air chromatography, and the amount of AKD can also be measured indirectly, which is the main idea of document 2. Document 2 also reviews two traditional methods of assays: iodine titration (iodine perchloride required) and potion titration (allowing AKD to react with axon, and then using chloric acid titration excess?
Simpler occasions (as in some modeled experiments) can also be used to measure the amount of AKD using ultraviolet visible spectroscopy
Disclaimer: If other test methods are found later, they will be added at any time.
References:
- Sunil Kumar, Vipul S. Chauhan, Swapan K. Chakrabarti.Separation and analysis techniques for bound and unbound alkyl ketene dimer (AKD) in paper: A review, Arabian Journal of Chemistry, 2016, 9, S1636-1642.
2.Ning Yan, Xiao-Fang Wan, Xin-Sheng Chai, Run-Quan Chen, Chun-Xia Chen. Determination of the content of alkyl ketene dimer in its latex by an ionic-liquid assisted headspace gas chromatography. Journal of Chromatography A, 2017, 1530, 19-22.
3.Lijun Wang, Lingzhi Luo, Jin Wang. Pretreatment to improve adsorption and effectiveness of wet end chemicals for a bleached chemithermomechanical pulp. TAPPI Journal, 2011, 8: 43-49.