Research And Applications Of Peptizers On Mastication In Natural Rubber

Mastication is an essential process in processing of natural rubber, while using peptizer can reduce the viscosity of NR quickly. This paper studied the effect of environment friendlychemical and physical peptizers on mastication and properties of natural rubber. The main contents were as follows:Firstly the effects of the dosage of peptizer DBD, temperature of mastication, rotor speed and mastication time on the mastication efficiency of natural rubber were investigated. Secondly the effects of RP66 and RP68 on energy consumption, Mooney viscosity, scorch and curing characteristics, physical and mechanical properties, rheological properties, dynamic viscoelasticity, swelling properties of NR compounds were studied and compared with A86 and SJ103. It was generally found that Mooney viscosity decreased, mobility and pseudoplastic increased with the increasing dosage of RP66 and RP68. The Mooney viscosity of NR compounds decreased by 12.5% and 18.6% when adding 0.2 phr RP66 as well as RP68. The scorch changed little, while the curing time shorten, the maximum and minimum elastic torque both declined. Shore hardness, tensile strength, elongation at break, tear strength and rebound of NR vulcanizates have declined, while 100% and 300% modulus changed little. RPA test showed that the Payne effect of NR compounds lower when adding the chemical peptizers, and the dispersion of filler was improved. Crosslinking density decreased. Dynamic mechanic analysis indicated that the glass transition temperature lower than control compound, at the meantime the wet skid resistance was improved.The application of unsaturated fatty acids RF50, RF60 and aryl zinc RF80 as physical peptizers in NR masticated were discussed. Physical peptizer reduce the viscosity through lubricantion without reducing the molecular weight of rubber. The results showed that energy consumption and Mooney viscosity of natural rubber peptized with physical peptizers declined. Scorch characteristic change little, the curing time extended, and the maximum and minimum elastic torque both declined. The modulus at 100% and 300%, tensile strength, shore hardness change little. RPA test indicated that the Payne effect of NR compounds lower when adding the physical peptizers, the dispersion of carbon black was improved. DMA test showed that the Tg of vulcanizates added RF50, RF60 and RF80 declined. The anti-reversion of physical peptizers were investigated, and it was found that they had a good improvement in anti-reversion of NR.