| A lot of new types of wet end chemicals emerge recent years, and better results attained in factual use. Because many phenomena occurred during the usage of chemicals in papermaking could not be explained well, it is necessary to study their intrinsical characteristics further so as to understand them will be do and why them will be do.Amphoteric polyacrylamide is a newly aid appeared at the few years ago, it has unexampled advantages over other one component aids.Polyacrylamide (PAM) is a general designation of a kind of homopolymer and copolymer of acrylamide (its molecular formula is CH2=CHCONH2) and its derivative.The product modality PAM are mainly divided into colloidal, powdery and emulsive, it can also be classified by its ions carried, i.e. non-ion, anion, cation and amphoteric ion.Amphoteric polyacrylamide is a multi-functional water soluble macromolecule material, and expected to be used in water processing, petroleum-drilling, mining, papermaking, fluid transportation, leather tanning etc.Firstly, copolymerization reaction is carried out with acrylamide, crylic acid monomer and cation monomer. Through adjusting the amount of oxidant, reductant and monomer concentration, at room temperature and pH around 6.4, a series of PAM of difference molecular weight were made with water-dissolvable polymeric method. Several factors affecting synthesizing of PAM were discussed, infrared spectrum and nuclear magnetic resonance hydrogen spectrum were applied to analyze the structure of synthesized amphoteric PAM,and compared with other PAM carrying different ion.Pulp slurry suspension is a complex multi-component system, it contents filler, starch and some other special chemical aids in addition to pulp fiber and fibril. So it is very important to understand wet end chemical characteristics of pulp slurry suspension.Secondly, factors influencing charge decay of pulp slurry suspension, such as stirring rate, pulp species, adding amount of polyelectrolyte, adding amount of cationic polymer etc. were discussed.Carboxyl contents in different pulp slurry suspension were measured and various factors affecting on content of pulp carboxyl were discussed.Specific surface and specific volume of different pulp were measured with fluid-permeability method and some affecting factors such as beating degree were taken into account.Thirdly, Britt Dynamic Drainage Jar which to evaluate retention and drainage in lab was used to seeing about the effect of amphoteric PAM and others chemical parameters' effect on first pass retention (FPR) were considered also.The effects of amphoteric PAM at different conditions on drainage operation of different pulp slurry suspension were studied and compared the impact with other PAM carrying cationic ion.The effects of pH and adding amount of amphoteric PAM on pulp slurry suspension charge were studied and probed briefly into the relationship between electric conductivity and CTR.Zeta potential and electric conductivity of different pulp slurry suspension and pulp slurry filtrate were measured respectively with MUETEK System Zeta Potential . SZP 04 and Model JS94 Zeta Potential and relationships of them were investigatedFinally, cases of retention and drainage adding different aids in different pulp slurry suspension were viewed at PHILIPS model XL30 environmental scanning electrical microscope (ESEM ) .Studies show that electric charge's affect carried by polyelectrolyte is the mainly retention and drainage mechanism of amphoteric PAM. Amphoteric PAM has a effect in pulp slurry system same as mucilage glue, they add bonding force among bonding point of fibre-fibre and fibre-fibril, in other words, amphoteric PAM takes effect as bridge and tache in the system. Subsequently, mechanical trap for fine particle take place when bonding of fibre to some extent and fibre mat formed. So, the retention and drainage mechanism of amphoteric PAM is integrate results on which all kinds of affecting factors effect, i.e. they have electric charge neutra...
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