芳烃油用量对充油镍系BR性能的影响

EFFECT OF AROMATIC HYDROCARBON OIL CONTENT ON PROPERTIES OF OIL-EXTENDED BR WITH NICKEL CATALYST

用干式一步充油法制备了不同芳烃油填充量的高ML充油镍系顺丁橡胶。考察了充油胶的ML-油效应规律及充油量对其加工性能和物理机械性能的影响。结果认为,充油量为30～40份时充油胶的辊筒行为优于相应的基础胶和BR9000,ML-油效应规律趋于平稳。随充油量的增加,充油胶的耐热老化性提高,压缩生热降低,拉伸强度和300％定伸应力呈线性下降。充油量以35～40份为宜,此时拉伸强度保持率为90％±5％,综合性能较好。

The oil-extended BR has been commercially used in recent years . Its obvious advantage is to dilute rubberwith less expensive extender oil. In addition , the oil can improve the processability of the rubber .This enables the use of a higher molecular weight rubber, which ,in turn , yeilds mechanical properties similar or superior to those of a low molecular weight rubber without oil extension .The cis-l,4-polybutadiene rubber polymerized with nickel catalyst system (NiBR) was prepared in a 40L caldron by adding the regulator of molecular weight , obtaining cis-1,4 units more than 96% , intrinsic viscosity [η] 3 -5 dL/g .ML1+4100°C65 - 90. It was then mixed on a constant rate mill by adding aromatic hydrocarbon oil in the range of 10 -50 phr .The oil -effects of the oil-extended NiBR were investigated and stress was laid on the oil content on the processing and mechanical properties of oil-extended NiBR . Figure shows that the Mooney viscosity of oil -extended NiBR decreases with the increase of oil content , which is more obvious in the range of low content than in the range of high content .It is interesting to mention that the oil-extended NiBR with lower ML had a more distinct oil effect than that with higer ML , and itsquality might thus be controlled . It is also seen that the tensile strength , 300% modulus , Shore hardness , impact resilience , heat build-up and tear strength of the vulcanizates decrease with the increase of oil content , while the elongation at break increases .Table shows that the permanent set , wear resistance and heat aging resistance of the vulcanizates decreased with the increase of oil content .whereas the roll ability became better gradually . This is attributed to the fact that the extender oil plays a role in diluting the rubber molecules to weaken the force between the molecules .The results show that the roll ability of oil-extended BR is better than that of corresponding raw BR and BR 9000 when the oil content is 30 - 40 phr and the oil effect of Mooney viscosity tends to stableness ; and when the oil content is 35 - 40 phr , the retention of tensile strength of the vulcanizates is 90% ±5% and the vulcanizates possess good comprehensive properties .