SYNTHESIS AND APPLICATION OF ANIONIC ACRYLIC EMULSION USED AS PAPER WET-STRENGTH ADDITIVE

The anionic acrylate emulsion used as wet strength agent was synthesized by polymerization of butyl acrylate.(BA) as soft monomer, styrene (St) as hard monomer, sodium dodecyl sulfate (SDS) and dodecyl polyoxy ethylene (OP-10) as emulsifiers under nitrogen. Factors such as ratio of SDS to OP-10, total dosage of SDS and OP-10, dosage of initiator, type and dosage of functional monomers were investigated. The optimal conditions for polymerization were determined: the ratio of SDS to OP-10 was 1:2, total dosage was 8%; the dosage of initiator was 0.25 g, including 0.15 g in seeded polymerization process and 0.1 g in shell polymerization process; the functional monomer dosage was 7.5 g. Furthermore, the application of synthesized anionic polystyrene-butyl acrylate-methacrylic acid (APSBM) emulsion used as wet strength agent was also investigated. The results showed that the effect of single use of APSBM was not good, but simultaneous use of 0.3% APSBM and 0.7% PAE showed great improvement of wet strength to 38%, increased by 50% compared with single use of 1% PAE, also the folding endurance increased by 54.3% compared with 1% PAE. SEM photographs showed that blank paper had a loose structure with large interspace between fibers, and the appearance of paper treated with 0.7% PAE and 0.3% APSBM had a close crosslinking which could increase bonding strength between fibers, thus, improved the wet strength of paper.