Investigation Of The Effects Of Hydroxymethyl Lignin On Reinforcing NBR And Enhancing Adhesion Between Rubber And Brass-plated Steel Cord

Lignin, as a renewable natural polymer material, is mainly obtained from the extraction of the pulp waste liquid. In this paper, hydroxymethyl lignin/ butadiene-acrylonitrile rubber(NBR) latex co-precipitation rubber was choosed as the raw material due to the structure of hydroxymethyl lignin modified by formaldehyde similar to HRH adhesion system. The reinforcement of HL for NBR and the influence of HL on the adhesion between rubber and brass-plated steel cord were studied. The effect of hydroxymethyl lignin instead of HRH adhesion system on the adhesion between rubber and brass-plated steel cord using in steel wire weaving hose was investigated. And it is found that hydroxymethyl lignin can enhance the adhesion between between rubber and brass-plated steel cord, close to the effect of HRH adhesive system. On this basis, the effect of hydroxymethyl lignin/silica ratio on adhesion properties was also studied.The influence of hydroxymethyl lignin on reinforcing effect of rubber and adhesion properties was firstly investigated. The result showed that hydroxymethyl lignin could be good reinforcing NBR and has a very good dispersion in rubber. The tensile strength of NBR/hydroxymethyl lignin(100/100) vulcanizate reached 18.4MPa. H pull-out force increases with increasing of the hydroxymethyl lignin content. When the dosage is 100 phr, H pull-out force can achieve 135 N, which can explain hydroxymethyl lignin enhancing the adhesion between NBR and brass-plated steel cord. With the increase of hydroxymethyl lignin, modulus of the rubber matrix increases and adhesive failure occurred from the adhesive surface to rubber phase.Comparison hydroxymethyl lignin with HRH adhesion system showed that the reason is that hydroxymethyl lignin not only has good compatibility with NBR, but also has good affinity with the surface of brass-plated steel cord. The high reactive hydroxymethyl group of hydroxymethyl lignin, which is similar to benzodiazepines- formaldehyde resin, promotes the adhesion between rubber and brass-plated steel cord. The acidic surface of hydroxymethyl particle, which is similar to silica, prolongs the curing time of the rubber compound, guaranting the rubber vulcanization and adhesion interface formation taking place simultaneously. When the content of hydroxymethyl lignin is 30phr~40phr, the adhesion effect of hydroxymethyl is closed to HRH adhesion system.The effect of hydroxymethyl lignin/silica ratio on adhesion properties of NBR and other properties is also studied. The result showed that hydroxymethyl lignin could enhance the modulus of rubber matrix; silica could proplong the curing time of the rubber compound. The synergy between hydroxymethyl lignin and silica could enhance adhesion between rubber and brass-plated steel cord effectively.