TBIR改性BIIR/NR共混物的结构与性能

Structure and Properties of Brominated Butyl Rubber/Nature Rubber(BIIR/NR) Blends Modified with TBIR

研究了新型合成橡胶——高反式-1,4-丁二烯-异戊二烯共聚橡胶(TBIR)对全钢轮胎气密层并用橡胶——溴化丁基橡胶(BIIR)/天然橡胶(NR)(质量比70/30)的改性作用,探讨了BIIR/NR/TBIR共混物的交联密度、填料分散性及力学性能,特别是并用硫化胶的气密性及屈挠疲劳性能等.结果表明,与无定型的BIIR和NR相比,结晶性TBIR的引入提高了炭黑填充的BIIR/NR/TBIR混炼胶的强度和模量,且随着TBIR用量的增大,混炼胶中TBIR的结晶熔融峰更明显,混炼胶的强度与模量显著提高.硫化特性结果表明,随着TBIR用量的增大,BIIR/NR/TBIR共混物的硫化速率略有提高,交联密度略有降低;TBIR用量为10~30份(生胶总质量的10%~30%)时,BIIR/NR/TBIR硫化胶在机械性能基本保持不变的情况下,耐热氧老化性能提高10%以上,耐一级屈挠疲劳性能提升2~5倍,气密性提高17%.炭黑分散结果表明,经过动态疲劳实验BIIR/NR硫化胶中炭黑聚集体的平均粒径增大至11.5μm,明显大于BIIR/NR/TBIR硫化胶中炭黑聚集体的平均粒径.对含TBIR硫化胶在周期性应力应变过程中的结构演变及对耐疲劳裂纹引发性能的影响机制进行了探讨,结果表明,TBIR可改性BIIR或者BIIR/NR制备高抗裂口引发的全钢轮胎气密层材料.

As a new generation of synthetic rubber,trans-1,4-poly（butadiene-co-isoprene） copolymer rubber（TBIR） was used to modify brominated butyl rubber（BIIR）/nature rubber（NR） blends for high performance inner liner stocks in all steel radial truck tire,and the crosslinking density,filler dispersion,physical and mechanical properties including gas permeability and flexual fatigue resistance of the BIIR/NR/TBIR blends after crosslinking were studied in details. The results indicate that the carbon black filled BIIR/NR/TBIR compounds show increased green strength and modulus with increased TBIR content,and DSC curves prove the crystallizability of TBIR component in the compounds and the crystallization peaks from TBIR can still be detected in the BIIR/NR/TBIR vulcanizates. Blending TBIR with BIIR/NR,the optimum curing time（t90）and the crosslinking density of the compounds slightly reduced. The BIIR/NR/TBIR vulcanizates showed excellent properties,such as improved hot-air aging resistance（10% higher） and air barrier resistance（17% higher）,and greatly improved the 1 st-class crack resistance（2 to 5 times higher）. The mean size of the carbon black aggregates in BIIR/NR vulcanizate after fatigue test became larger than that in BIIR/NR/TBIR vulcanizates. Finally,the structure evaluation of the BIIR/NR/TBIR vulcanizates and its influences in the crack initiation resistance during the dynamic process with periodical stress and strain were discussed in details. TBIR is deemed as an ideal candidate to modify BIIR or BIIR/NR blends for truck tire inner liner stocks with higher crack initiation resistance without deteriorating of other properties.