Study On The Synthesis And Retention Effect Of Organosilicon-modified Phenol-formaldehyde Resin

Waste paper have been becoming one of the important material in papermaking industry for saving resource and reducing the cost. The retention of fiber fines and filling has been becoming more and more important to paper mills because of saving cost of production. The normal retention aids can not be made good use of their actions for recycled fiber because the poor characteristics of waste papers.Organosilicon polymer is a kind of organic macromolecule materials and the element silicon is contained in molecular structure. Organosilicon polymer has -Si-O-Si- bond and organic group branch bond, so it has double merits of organic and inorganic compounds. Some organosilicon oil can be used in papermaking industry, their molecular weight are from hundreds to thousands. They are often used in papermaking industry as resist—stickiness aids, flexible aids, waterproof aids, defoaming aids etc. Organosilicon polymer has also some excellent merit in wet end.Phenol-formaldehyde resin (PFR) is modified with octamethyl cyclotetrasiloxane D4 to synthesize organosilicon-modified phenol-formaldehyde resins (MPFR) under suitable conditions in this paper. The MPFR and polyethylene oxide (PEO) comprised a new binary retention system, which was used for deinked pulp of waste paper. The experimental results showed system could improve the retention and the physics property of paper.The sum total of study on the subject is contained as the follows:1. The Synthesis and influential factors of MPFR: The synthesis and capability modified phenol-formaldehyde resin were mostly influenced by the factors that include type of phenol-formaldehyde resin, the dosage of organosilicon, reaction times, reaction temperature, pH value of reaction mixture, mol ratio of reagents et al.2. The comparing of capability and the use of MPFR: Using the dynamic retention experiments of recycled newspaper pulps in which MPFR and PEO were added, we studied on the conditions of application of the MPFR and PEO system. It is found that effects of the retention system would be influenced a certain extent by the ratio between MPFR and PEO, dosages of retention aids, pH values of the pulp system, shearing force the system receiving and the action time of retention aids.3. The comparing of different retention systems and the effects of MPFR and PEO system to other agents: MPFR and PEO system was compared with other retention systems, such as cationic polyacrylamide (CPAM), phenol-formaldehyde resin and polyethylene oxide system, hydrocol system and compozil system. And the effect of retention of MPFR and PEO system was better than others for recycled newspaper pulp. The effect of MPFR and PEO system to other agents, for example sizing agent, strength agent and filling, were also studied.4. Studies on mechanisms of the MPFR and PEO retention system: The mechanism of the MPFR and PEO retention system was studied from several sides, such as the changes of electric potential of pulp, the changes of the granularities of fiber fines and adsorptions of fibers and filling to MPFR et al. It was shown that the functions of charge neutralization and joint action and complexation played important roles to retentions of fiber fines and filling.